Search results for "Thermal"

Comparison of analytical methods and AI tools for material characterisation in hot forming

2002

Abstract Hot forming processes probably represent the most ancient of forming operations and what is more they are still today commonly used in modern mechanical industry in order to obtain sound parts, achieving large deformations with a limited required power. Hot metal forming operations are characterised by a large number of physical and thermal phenomena which have to be taken into account in order to model and design the processes themselves. Actually several thermally activated phenomena occur during the forming processes such as recovery, recrystallisation, grain growth, precipitation, allotropic transformations, etc. In this paper the comparison between an analytical method based o…

Graphene oxide surface functionalization of polymeric scaffolds for the recruitment and thermal ablation of tumor cells

2017

A geochemical traverse along the “Sperchios Basin e Evoikos Gulf” graben (Central Greece): Origin and evolution of the emitted fluids

2014

The studied area is a 130 km long fast spreading graben in Central Greece. Its complex geodynamical setting includes both the presence of a subduction slab at depth responsible for the recent (Quaternary) volcanic activity in the area and the western termination of a tectonic lineament of regional importance (the North-Anatolian fault). A high geothermal gradient is made evident by the presence of many thermal springs with temperatures from 19 to 82 C, that discharge along the normal faults bordering the graben. In the period 2004e2012, 58 gas and 69 water samples were collected and their chemical and isotopic analysis revealed a wide range of compositions. Two main groups of thermal waters…

Catalogue of the main gas manifestations in the Hellenic territory: a first step towards the estimation of the nationwide geogenic gas output

2015

Quantification of gaseous emissions in geological systems is an important branch because it is a major source of greenhouse gas to the atmospheric budget. Of geological environments, there are two different categories: the first category includes emissions of the predominant carbon dioxide (CO2), while the second includes emissions of the predominant methane (CH4). The Hellenic territory has a very complex geodynamic setting deriving from a long and complicated geological history. It is strongly characterized by intense seismic activity and enhanced geothermal gradient. This activity, with the contribution of an active volcanic arc, favours the existence of many cold and thermal gas manifes…

Catalogue of the main gas manifestation of Greece: a basis for nationwide estimations of gas hazard and total geogenic gas output

Estimation of CO2 release from thermal springs to the atmosphere

2019

Introduction Geodynamically active regions have long been recognized as areas of anomalous Earth degassing [Irwin and Barnes, 1980]. Areas found at plate boundaries are characterized by seismic, volcanic and geothermal activity as well as ore deposition. These processes are enhanced by the circulation of hydrothermal fluids in the crust, which transport volatiles from the deep crust or mantle to the surface [King, 1986]. Kerrick and Caldera, [1998], were the first to indicate the significant contribution of the CO2 degassing by extensional tectonic and hydrothermal activity in metamorphic belts during the Phanerozoic. Moreover, further studies concerning gas emissions from diffuse degassing…

New approach for synthesis of poly(ethylglyoxylate) using Maghnite-H + , an Algerian proton exchanged montmorillonite clay, as an eco-catalyst

2017

International audience; In this works, we have explored a new method for a green synthesis of poly(ethylglyoxylate) (PEtG). This method consists on using a montmorillonite clay called Maghnite-H+ as an eco-catalyst to replace triethylamine which is toxic. Cationic polymerization experiments are performed in bulk conditions at three temperatures (-40 degrees C, 25 degrees C, 80 degrees C) and in THF solutions at room temperature (25 degrees C). At 25 degrees C, an optimum ratio of 5 wt% of catalyst leads to molar masses up to 22000 g/mol in THF solutions. Polymerizations in bulk conditions lead to slightly lower masses than experiments conducted in THF solutions. However, bulk polymerization…

Extraction of thermal characteristics of surrounding geological layers of a geothermal heat exchanger by 3D numerical simulations

2016

Ground thermal conductivity and borehole thermal resistance are key parameters for the design of closed Ground-Source Heat Pump (GSHP) systems. The standard method to determine these parameters is the Thermal Response Test (TRT). This test analyses the ground thermal response to a constant heat power injection or extraction by measuring inlet and outlet temperatures of the fluid at the top of the borehole heat exchanger. These data are commonly evaluated by models considering the ground being homogeneous and isotropic. This approach estimates an effective ground thermal conductivity representing an average of the thermal conductivity of the different layers crossed by perforation. In order …

Efficiency improvement of a ground coupled heat pump system from energy management

2011

The installed capacity of an air conditioning system is usually higher than the average cooling or heating demand along the year. So, most of the time, the system is working under its actual capacity. In this contribution, we study the way to improve the efficiency of a ground coupled heat pump air conditioning system by adapting its produced thermal energy to the actual thermal demand. For this purpose, an air conditioning system composed by a ground coupled heat pump and a central fan coil linked to an office located in a cooling dominated area was simulated, and a new management strategy aiming to diminish electrical consumption was developed under the basic constraint that comfort requi…

Farbenwandel der Zahnhartgewebe als Zeichen thermischer Sch�digung

1985

Die menschlichen Hartgewebe lassen nach thermischer Schadigung gewisse Ruckschlusse auf Brandparameter zu. Neben morphologischer Destruktion ist an den Zahnhartgeweben ein Farbenwandel zu beobachten. Diese Form der Zustandsanderung von Schmelz, Dentin und Zement ist an 330 menschlichen extrahierten Zahnen unter definierten Zeit-und Temperaturintervallen studiert worden. Die Farbphanomene als Ergebnisse der Gluh- und Aufheizversuche sind mit Hilfe der DIN- und RAL-Farbregister ausgewertet worden. Am leichtesten last sich die Zementfarbe bestimmen, da markierende Belage oder Konkremente fehlen. Auserdem bleibt die Wurzelform relativ lange erhalten, wahrend die Zahnkronen zerfallen konnen. Die…