let f, g and h be non-empty graphs. the notation f → (g,h) means that if any edge of f is colored by red or blue, then either the red subgraph of f con- tains a graph g or the blue subgraph of f contains a graph h. a graph f (without isolated vertices) is called a ramsey (g,h)−minimal if f → (g,h) and for every e ∈ e(f), (f − e) 9 (g,h). the set of all ramsey (g,h)−minimal graphs is denoted by ...

this paper presents the results obtained from the life cycle assessment (lca) of the productionof sicilian artichokes (cynara scolymus) with the aim of reducing impacts, interpreting the results, suggesting possible improvements and enriching the sustainability knowledge already existing in the agro food field. artichokes represent one of the excellent italian agricultural products even if stil...

urban sinks accumulate phosphorus and other elements and may serve as sources of secondaryraw materials. this paper evaluates phosphorus sources based on their environmental impact. in a life cycleassessment (lca) the conventional production was used as a yardstick against which tomeasure the performanceof two recycling options: spreading of sewage sludge and phosphorus recovery from municipal ...

conceptual design of a waste heat recovery cycle is carried out in attempt to enhance the thermal efficiency of a steam power plant. in the recovery system, super-critical an co2 is employed as the working fluid operating in a brayton cycle. low grade heat rejected by the flue gases through the stack is used as the primary heat source, while a secondary heat exchanger utilizes the hot gases lea...

magnetic levitation (maglev) is amongst the most advanced technologies that are available to the transportation industries. it has already been noticed by decision makers in many countries around the globe. contrary to such high levels of interest, there are no practical algorithms available to the engineers and/or managers to assist them in analyzing economics of the maglev systems. therefore,...