Thermal-hydraulic separators unveiled

A key issue in the design of heating/cooling networks consists in attaining the hydraulic independence of the connected circuits while simultaneously providing the required flow rate of thermal fluid at the design temperature under different operation loads. In this respect, thermal- hydraulic separators offer a valid alternative over other devices used for the same service (as, e.g., heat exchangers, accumulation tanks or double-tee junctions), providing the opportunity to integrate the functions of de-gassing and of removal of solid debris in a single piece of equipment.The present numerical investigation improves the characterization and modelling of these devices. The major outcome of the proposed research is the improvement of the base model widely-used in the design of thermal-hydraulic networks encompassing thermal-hydraulic sep-arators. The proposed model accounts for the turbulent mixing within the device. Furthermore, we propose an original network representation of thermal-hydraulic separators, which supports the physical intuition about their internal flow patterns and can be integrated in thermal network solvers used for plant design and optimization. To the authors' best knowledge, this is the first numerical investigation accounting for the impact of the internal mesh strainer on the behaviour of the device

Rationalization and optimization of waste management and treatment in modern cruise ships

Here we report over possible optimizations onboard cruise ships in the management of glass, paper and cellulosic waste, ranging from simple rationalization of the materials' use (for glass and paper) to the recovery of some of the energy embedded in paper and other cellulosic waste. This latter option is investigated considering two possibilities: i) the recovery of thermal energy from incinerator's flue gas by means of an absorption plant, ii) the production of syngas to be directly fed to the ship engines. For each option, we calculated the achievable benefits in terms of reduced fuel consumption, avoided CO2 emissions and cost savings (evaluated on the basis of the avoided fuel consumption). Finally, on the basis of the previously calculated benefits, we defined three different scenarios, each including the rationalization of glass and paper waste management, topped by different combinations of thermal energy recovery/syngas production. We then evaluated these scenarios in terms of environmental and economic benefits. This analysis showed that even trivial approaches, as a simple rationalization of paper consumption, can allow consistent advantages over existing waste management policies; moreover, syngas generators for treating cellulosic waste emerged as very effective tools for lowering the environmental impact of modern cruise ships. Joining these two strategies allows notable savings in terms of fuel, CO2 emissions and ship operational costs, and could represent a path for sizably reducing the environmental footprint of cruise ships

Selection of a Suitable Waste to Energy Technology for Greater Beirut Area Using the Analytic Hierarchy Process

Waste to Energy (WtE) is becoming an interesting option for many countries as an effective waste management solution. The goal of this study is the selection of a suitable WtE technology for the treatment of municipal solid waste in Greater Beirut Area (GBA). In adopting a potential WtE technology for solid waste treatment in GBA, the protection of the environment and citizens health is mandatory, but it is also evident the pressing need for economically feasible new electrical energy sources. For a well and an efficient functioning of a WtE plant, an appropriate supply chain system of municipal solid waste should be guaranteed. The selection of a suitable WtE technology is a complex decision and to achieve the stated objective the Analytic Hierarchy Process (AHP) method was employed and experts in the waste management sector were consulted to formulate the model. AHP analysis was performed using SpiceLogic software. Results indicate that Composting is the best choice with a global score of 0.33, followed by Anaerobic Digestion which acquired 0.21 and Incineration ranked as the third preferred technology obtaining 0.14. A sensitivity analysis was conducted to ensure the results consistency, assessing the reliability of the experts’ judgments

Effetti della comunicazione sulla rappresentazione grafica infantile

ET` EVOLUTIV

Empathy in history. Understanding a past institution (ordeal) in children and young adults when description and rationale are provided.

A total of 150 students, from 8-9 to 25 years, were interviewed about ordeal1 in the Middle Ages, after reading a shorter and simplified version of a text used in previous research on this topic (e.g., Lee & Ashby, 2001). Unlike previous studies, at all ages nearly all students understood that ordeal involved the intervention of God, and was related to religious beliefs different from the present. With age, there was an increase in the number of students also referring to the backwardness of the Middle Ages, or stating that at least some Medieval peoples did not expect ordeal to be decisive about the guilt or innocence of an accused, using it instead to find a culprit in any case, or as a punishment or deterrent

Conceptions about the origin of species in Italian children who have, and have not, been taught about the topic

Investigations of people\u2019s understanding of the evolution of species have focused mainly on secondary school and university students. Very few investigations have taken into consideration younger students, and none have related children\u2019s ideas about the origin of species to formal instruction on this topic. To help fill this gap, the present study examines the effect of this instruction in elementary school children by comparing Italian second graders (n = 21; age = 7 years, 1 month, to 8 years, 7 months) with third graders (n = 18; age = 8 years, 1 month, to 9 years, 4 months) who had been taught about \u201cthe earth before humans\u201d for several months in keeping with the Italian National Syllabus for this grade level. Semistructured interviews were used to examine children\u2019s thoughts about speciation. The majority of second graders used a creationist framework, whereas most third graders used a mixed framework (referring to both creation and evolution) or an evolutionary framework. However, children did not know about the mechanism of evolution and considered it to be the result of the passage of time, the use and disuse of body parts, or the need to adapt to a changing environment, as suggested by their teacher and textbooks

Design and Assessment of an Innovative Thawing Equipment for the Professional Food Service

The need for faster, safer, and environmentally compatible thawing methods is perceived in different branches of food industry, as, e.g., in the fast-food sector. We investigate a prototype of jet-impingement, batch-process thawing machine, exploiting high-speed impact of heated atmospheric air onto food items. The results of combined experimental and numerical study show the promising potential of this technology beyond the expected increased thawing rate, especially when the proposed two-side arrangement of the jets is adopted. A series of thawing indicators are calculated and used to account for the thawing uniformity and the risk of bacterial proliferation. A computationally efficient two-stage model of the considered thawing process is conceived, which can be used for design and optimization