thermal behaviour

During the previous 2 years a new "HybridTPS" thermal protection system is under development at the NCSR "Demokritos" in Greece. The system exploits the synergy between a rigid, high refractoriness porous ceramic and a contained reinforced ablator as a heat-sink and is aimed at ...

PurposeThe paper aims to focus on airflow and heat transfer inside the human nasal cavity. The contribution of this work is the inertial analysis of the momentum and thermal stress of the cavity throughout the respiratory cycle.Design/methodology/approachBy means of computer tomography scans, an accurate three‐dimensional anatomical representation of the human nasal cavity was obtained. A three‐dimensional numerical model is presented in order to predict the time evolution of flow patterns during a quiet breathing cycle, covering inhalation and exhalation. An inertial analysis of the momentum and a detailed study of the thermal behaviour during the breathing cycle is carried out.FindingsHead loss, velocity and temperature values are in agreement with experimental results from previous studies. Based on these results, the influence of the inhalation and the exhalation on the flow pattern and air conditioning has been reviewed. Results suggest that the anterior and posterior turbinate...

The thermal behaviour of halloysite fully expanded with hydrazine-hydrate has been investigated in nitrogen atmosphere under dynamic heating and at a constant, pre-set decomposition rate of 0.15 mg min-1. Under controlled-rate thermal analysis (CRTA) conditions it was possible to resolve the closely overlapping decomposition stages and to distinguish between adsorbed and bonded reagent. Three types of bonded reagent could be

© 2018 Dr. Yalda SouraniThe Bakhtyari is one of the most important tribes in Iran, with a rich culture, which have lived a traditional lifestyle in the middle of the Zagros Mountains for centuries. While there has been a lot written about the Bakhtyaris’ history, society, economy, culture, customs and tradition, very little research has been done on their architecture and their environmental strategies. To fill this gap, my research is concerned with both practical engagements and technical analysis concerning their black tent and its environmental behaviour. This is organised in two parts: Part one documents the Bakhtyaris’ culture by means of their traditional summer settlements in the yeylaq and their climatic solutions. It outlines the theoretical implications of nomadic life in Iran, and the spatial distribution of nomads. I explain how the vast area of the Bakhtyaris’ land is allocated according to the structure of their society. As the main focus of my research is on the Bakh...

The nose geometry of a hard and brittle metal cutting tool is generally modified in order to avoid the premature failure due to fracture under tensile stresses. While most research findings point to a favourable mechanical load pattern, the possible influence of the shape of the geometry on the thermal fields and the consequent changes in the stressed state of the tool seem to have attained less attention. The present work aims at establishing the thermal behaviour of bevelled tools under varying geometrical and process parameters. Data generated from statistically designed experiments and quick-stop chip samples are coupled to conduct numerical investigations using a mixed finite and boundary element solution to obtain the temperature distribution in bevelled carbide inserts. Due consideration is given to the presence of the stagnation zone and its size and shape. While the cutting forces and temperatures increased owing to the blunt shape of the tool, the possible absence of tensi...

There is a strong trend in developing small satellites for different space missions (space science, communications, technology verification, earth observation, military applications, and others). For its correct development, the small satellite needs to run environmental tests, including a Thermal-Vacuum Test, which is executed in a Thermal-Vacuum. The ThermalVacuum Chambers are used to simulate as closely as possible the space environment conditions experienced by satellites in operation. These systems analyze satellite thermal behavior and functionalities to ensure mission success and survivability. Most of ThermalVacuum Chambers in several space research centers were originally designed to test large satellites. When testing small satellites in thermal-vacuum conditions, the available chambers in the market are usually oversized for small satellites, which usually increases testing costs complicating the mission development. Because of that, our multidisciplinary professionals te...

Concrete remains the most utilised construction material for building envelopes, which regulate the indoor temperature to achieve human thermal comfort. Often, the energy consumption for building performance appraisal is related to the thermal behaviour of building materials as heating, ventilation, and air conditioning systems all variously contribute to human comfort. Following the development of concrete technology, many types of concrete have been invented to serve several purposes in the construction industry. To clearly understand the concrete type tailored for the specifics of a construction project, the local climate, concrete mechanical properties, and concrete thermal behaviours should be primarily identified to achieve energy efficiency, which also suits the sustainability of global materials. This paper, therefore, reviews the modified concrete thermal behaviours in the tropical climate for more systematic city planning in order to achieve better energy efficiency. Urban...

Photovoltaic (PV) modules and solar thermal collectors are convectional solar systems that convert solar radiation into electricity and heat energy respectively. PV modules generate clean electricity and ideal for use in developing countries where human settlement is scattered in remote rural areas and no grid electricity is available. However, electrical conversion efficiency of commercial PV modules is still low (~20%) hence about 80% of the incoming solar energy is lost as waste heat which raises module temperature resulting into a reduction in its electrical efficiency. Hybrid photovoltaic/thermal (PV/T) solar collectors are innovative systems that generates heat and electricity simultaneously hence increases solar energy conversion efficiency of a PV module. A PV/T system is a PV module with a heat exchanger attached behind it for passing a colder fluid (usually air or water) for extracting useful heat and hence cooling the PV module. In the present work, a parametric model bas...

The improvement of the energy efficiency of buildings calls for the availability of tools for evaluating and simulating the thermal behaviour of buildings. These simulation tools generally need a complete input data set concerning the climatic conditions at a given location. In the most cases, this huge mass of data is very complex, so simple aggregation methods of the meteorological

Curing of diglycidyl ether of bisphenol-A (DGEBA) with phosphorus containing amide amines i.e. bis[3(3’-aminobenzamido phenyl)]methyl phosphine oxide (MB),bis[3(4’-aminobenzamido phenyl)]methyl phosphine oxide (PB), tris[3(3’-aminobenzamidophenyl)] phosphine oxide (MT) and tris[3(4’-aminobenzamido phenyl)] phosphine oxide (PT)and conventionally used curing agent 4,4’-diaminodiphenyl sulfone (D) was studied by DSC. The amines MB, PB, MT and PT were synthesised in the laboratory and were characterized by determining

This paper describes the thermal behaviour of blends of bisitaconimide (I) and bisnadimide (N) resins of similar structures. Bisitaconimides/bisnadimides based on 4,4'-diaminodiphenyl ether (E);2,2'-bis[4-(4-aminophenoxy)phenyl]propane (B); 1,3-bis(4-aminophenyl)benzene(R) and 1,4-bis(4-aminophenyl)benzene (H) were prepared and were designated as E-I/E-N; B-I/B-N; R-I/R-N and H-I/H-N respectively. Itaconimides had lower melting points and curing temperatures than that of corresponding nadimides. The blends of bisitaconimides and bisnadimides