Search results for "Conservation of energy"
showing 10 items of 12 documents
Dimensionless Stage-Discharge Relationship for a Non-Linear Water Reservoir: Theory and Experiments
2020
In the field of hydrology, stage&ndash
Marine reserves: size and age do matter
2008
Marine reserves are widely used throughout the world to prevent overfishing and conserve biodiversity, but uncertainties remain about their optimal design. The effects of marine reserves are heterogeneous. Despite theoretical findings, empirical studies have previously found no effect of size on the effectiveness of marine reserves in protecting commercial fish stocks. Using 58 datasets from 19 European marine reserves, we show that reserve size and age do matter: Increasing the size of the no-take zone increases the density of commercial fishes within the reserve compared with outside; whereas the size of the buffer zone has the opposite effect. Moreover, positive effects of marine reserve…
The Influence of Solar Power Plants on Microclimatic Conditions and the Biotic Community in Chilean Desert Environments
2016
The renewable energy sector is growing at a rapid pace in northern Chile and the solar energy potential is one of the best worldwide. Therefore, many types of solar power plant facilities are being built to take advantage of this renewable energy resource. Solar energy is considered a clean source of energy, but there are potential environmental effects of solar technology, such as landscape fragmentation, extinction of local biota, microclimate changes, among others. To be able to minimize environmental impacts of solar power plants, it is important to know what kind of environmental conditions solar power plants create. This study provides information about abiotic and biotic conditions i…
Partial self-consistency and analyticity in many-body perturbation theory: Particle number conservation and a generalized sum rule
2016
We consider a general class of approximations which guarantees the conservation of particle number in many-body perturbation theory. To do this we extend the concept of $\Phi$-derivability for the self-energy $\Sigma$ to a larger class of diagrammatic terms in which only some of the Green's function lines contain the fully dressed Green's function $G$. We call the corresponding approximations for $\Sigma$ partially $\Phi$-derivable. A special subclass of such approximations, which are gauge-invariant, is obtained by dressing loops in the diagrammatic expansion of $\Phi$ consistently with $G$. These approximations are number conserving but do not have to fulfill other conservation laws, such…
Municipal waste management in Sicily: practices and challenges.
2006
There are numerous problems yet to be solved in waste management and although efforts towards waste recovery and recycling have been made, landfills are still the most common method used in the EU and many other industrialised countries. Thermal disposal, particularly incineration, is a tested and viable alternative. In 2004, only 11% of the annual waste production of Italy was incinerated. Sicily, with over five million inhabitants, is the second largest region in Italy where waste management is now a critical problem. The use of landfills can no longer be considered a satisfactory environmental solution; therefore, new methods have to be chosen and waste-toenergy plants could provide an a…
Life cycle assessment of Italian citrus-based products. Sensitivity analysis and improvement scenarios
2009
Though many studies concern the agro-food sector in the EU and Italy, and its environmental impacts, literature is quite lacking in works regarding LCA application on citrus products. This paper represents one of the first studies on the environmental impacts of citrus products in order to suggest feasible strategies and actions to improve their environmental performance. In particular, it is part of a research aimed to estimate environmental burdens associated with the production of the following citrus-based products: essential oil, natural juice and concentrated juice from oranges and lemons. The life cycle assessment of these products, published in a previous paper, had highlighted sign…
Power Consumption Analysis of Operating Systems for Wireless Sensor Networks
2010
In this paper four wireless sensor network operating systems are compared in terms of power consumption. The analysis takes into account the most common operating systems-TinyOS v1.0, TinyOS v2.0, Mantis and Contiki-running on Tmote Sky and MICAz devices. With the objective of ensuring a fair evaluation, a benchmark composed of four applications has been developed, covering the most typical tasks that a Wireless Sensor Network performs. The results show the instant and average current consumption of the devices during the execution of these applications. The experimental measurements provide a good insight into the power mode in which the device components are running at every moment, and t…
Cogeneration from thermal treatment of selected municipal solid wastes. A stoichiometric model building for the case study on Palermo
2003
This paper aims to calculate the energetic and environmental effects of an integrated solid waste management system in Palermo, Italy. In particular, the thermal treatment of Municipal Solid Waste (MSW) with energy recovery is assessed. The current characterization at the local scale is taken into account. Two different options of collection are taken into account: (1) unselected wastes; and (2) sorted collection, according to the current Italian regulation. Combustion process is analyzed and the following features are calculated: (1) stoichiometric content of air and air excess; and (2) temperature and enthalpy of flue gases. Energy recovery is performed in the hypothesis of Hirn cycle bot…
Operative Gesichtspunkte bei der Diskussion des Weberschen Gesetzes
1977
The analysis of structures of argumentation in historical controversies is considered to be a basic contribution to the dynamics of theories. In this paper attention is drawn to the occurence of operational arguments in the history of physics. This is to be discussed especially in respect to the nineteenth-century debates on the consistency of Wilhelm Weber's electrodynamic law with the principle of conservation of energy.
Enseñanza de las ciencias : revista de investigación y experiencias didácticas
2021
Resumen basado en el de la publicación Resumen en inglés El tema de la energía es una parte muy importante de un curso de física, ya que proporciona un vínculo claro entre las diferentes secciones de física. Se analiza la enseñanza y el aprendizaje de la energía en el nivel secundario y se demuestra que los métodos tradicionales para enseñar energía: a) no consideran las ideas erróneas de los estudiantes, b) introducen la conservación de energía en mecánicas y termodinámicas, pero no aclaran si es un teorema o un principio, y c) no presentan la conservación de la energía como principio general de toda la física. Finalmente, se muestra un nuevo enfoque para la enseñanza de la energía. ESP