Search Results

You are looking at 1 - 10 of 21 items for :

  • "heat capacity" x
  • Materials and Applied Sciences x
  • Refine by Access: All Content x
Clear All

(conductivity, specific heat capacity, thermal diffusivity, and effusivity) is important in simulation and control of various food processing operations ( Datta, 2007 ). The photopyroelectric method (PPE) is one of the applied techniques by which

Restricted access

Abstract

The rise in energy prices, the need to conserve energy and the pressure to protect the environment promote the development of innovative eco-friendly thermal insulating foams for building applications. In this quest, a rapid and accurate method to measure the thermal conductivity of new foams is required during the research and product development stage. Temperature-modulated differential scanning calorimetry (MDSC) provides thermal conductivity values from heat capacity measurements on cylindrical samples less than about 20 mg in weight. This method is the basis of the ASTM E1952 standard method “Thermal Conductivity and Thermal Diffusivity by Modulated Differential Scanning Calorimetry”. In this work, the MDSC and the ASTM E1952 test methods are applied to thermal insulating foams used in construction applications. Measurements on polystyrene, polyurethane, and polyisocyanurate insulations demonstrate that MDSC possesses excellent repeatability, but its application through ASTM E 1952 provides inaccurate thermal conductivity values. Two sources of errors were identified, 1) the use of nitrogen as a purge gas, and 2) the use of an equation that inaccurately relates the measured heat capacity to thermal conductivity. Methods around these difficulties exist, but they remain untested with insulating foams.

Restricted access

A numerical study of the thermodynamic properties of a superconducting quantum cylinder in a longitudinal magnetic field is carried out. Closed-form expressions for the critical temperature, the free energy, the heat capacity jump, and the magnetization difference between the superconducting and normal phases as functions of the nanotube parameters are obtained in limit cases.

Restricted access

. Fig. 2. Labtech BL20001 electronic compact scale The mass of each specimen was taken and recorded in grams, the specific heat capacity adopted for each

Open access

,835 Molar heat capacity J (mol −1 ·k −1 ) 24.2 0.466 24.44 Results

Open access

specific energy, J/kg; T is the temperature, K; μ is the dynamic viscosity, kg/(m/s), τ ¯ ij is the averaged Reynolds stress for components, c p is the heat capacity at constant pressure, J/(kg/K), λ is the thermal conductivity, W/(m/K); δ ij is the

Open access

]. (1) η t h = Q u Q s The useful energy gain transferred to the fluid is defined as represented in Eqs. (2) and (3) [ 16 ]. (2) Q u = m ˙ . C p . f l u i d . ( T f l u i d , o u t − T f l u i d , i n ) where C p . f l u i d is specific heat capacity

Open access

Thermal capacitance (J/°C −1 ) cp Specific heat capacity (J/kg −1 ·°C

Open access