Temperature Of Solid Material Research Articles

Measurement of Thermal expansion coefficient of solid Materials by double slit Interferometric method

Thermal expansion coefficient is a regular coefficient to describe the variation of geometric characteristics of matter under the action of thermal expansion and cold shrinkage effect, and it is an important index to measure the thermal stability of materials. A device for measuring the thermal expansion coefficient of solid materials by Yang’s double slit interferometric method with variable double slit spacing is mainly composed of laser, sliding Young double slit structure, temperature measuring and controlling instrument, shading tube, receiving device and solid material to be measured. The solid material is heated by ring heater, the temperature of solid material is displayed and controlled by temperature measuring and controlling instrument, and the change of stripe spacing is recorded by linear CCD image sensor. Compared with the traditional optical leverage method, this measuring device and method can significantly improve the accuracy of the measurement results and reduce the uncertainty of the measurement results.

The Role of Aeration Intensity, Temperature Regimes And Composting Mixture on Gaseous Emission During Composting

The aim of the work was to compare production of N2O during composting with different temperature regimes, different aeration intensity and different input mixture. Two different mixtures of organic material with three levels of aeration underwent the composting process in two temperature regimes. Mixture A contained woodchips, separated pig slurry, fresh grass and tree leaves. Mixture B contained woodchips, tree leaves, grass and urea to optimize C:N ratio. This experiment was carried out in specially designed 70 liter fermentors. Oxygen and nitrous oxide were monitored in the exhaust air as well as pH, NO3− and NH4+ and temperature of solid material. The mixture with urea additive showed high N2O production when kept under low temperature; when the same mixture was kept in higher temperature, production of NO2 was 3 fold lower. However, the mixture without urea addition kept in high temperature shows almost no N2O production. Production of N2O was highest when nitrates concentration increased. Production of N2O is perhaps a by-product of nitrification, but also other pathways may contribute.

Models for Predicting Thermal Performance of Packed Bed Energy Storage System for Solar Air Heaters - A Review

Packed bed is generally recommended for attaching with solar air heater in order to store thermal energy of hot air. For designing such a system under the given system and operating parameters, it is required to predict performance of the system by using mathematical models. In the present paper an attempt has been made to discuss mathematical models reported in the literature for predicting thermal performance of packed bed energy storage system for solar air heaters. The designer may be benefited from the consolidated information reported in the present paper. The continuous use of fossil fuels resulted energy crisis and environmental threat. It is felt that renewable energy sources are quite capable of meeting energy demand of today's world. The use of renewable energy sources for meeting energy needs can conserve the conventional energy sources for more number of decades. Among renewable energy sources solar energy is considered to be one of the most dominating energy source. It has many advantages like large potential, free of cost, available everywhere, environment friendly etc. However time dependent nature is the major disadvantage of solar energy. In order to overcome this disadvantage it is required to attach an energy storage system with the solar energy utilization system. With such a provision the stored energy can be utilized in the absence of solar radiation or under peak load conditions. In case of solar air heaters it is required to store thermal energy of flowing hot air. Packed bed is generally recommended for such an application. Packed bed consists of a container in which solid material elements having good heat capacity remain packed. The hot air flows from top to bottom of the bed to transfer heat energy. The rise in temperature of solid material takes place and energy can be retained by having properly insulated packed bed. The stored energy can be retrieved by making flow of cold air from bottom to top of the bed. The schematic of packed bed energy storage system for solar air heaters is shown in Fig. (1). The working of such a system is described in detail by Duffie and Beckman (1).