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<p>Mathematical modeling of heat transfer is a common method utilized in designing thermal processes for food, modeling degradation kinetics of microorganisms and nutrients, designing food processing equipment as well as for process optimization and for ensuring scale-up feasibility of a product. It is essential to have all the necessary components for modeling including the geometry, boundary conditions, initial temperature, and the temperature-dependent thermal properties. Getting temperature-dependent thermal properties of food product is difficult due to the lack of effective and efficient devices or techniques. To show the influence of temperature-dependent thermal properties, retort processing of potato soup was simulated using both temperature-dependent (dynamic) and fixed thermal properties. Three methods, TPCell, Choi-Okos predictive model and KD2 Pro, were used to determine the thermal conductivity at 25°C and 120°C for comparison. The proximate composition of the sample was determined for prediction of thermal properties with the Choi-Okos model. The accuracy of simulation was evaluated based on the temperature at the cold spot and corresponding sterilization value. Results suggested that using temperature-dependent thermal properties in heat transfer modeling increased the accuracy of the simulation. Simulation performed with temperature-dependent properties obtained from TPCell matched very closely with experimental heat penetration data. Additionally, the sensitivity of temperature-dependent thermal properties obtained from TPCell in detecting variation in product formulation was evaluated. Four variations of potato soup were prepared to compare their respective lethality value. Thermal conductivity, specific heat capacity and density of the potato soups were measured, and simulation was performed using the measured thermal properties and a scheduled process as boundary conditions. Thermal properties of food product changed with the formulation which affected the processing time to achieve minimum lethality value. A significant difference in thermal conductivities was seen for these potato soups causing the scheduled process to be only suitable for thermal processing of some formulations while others would be undercooked that could lead to food safety risk. Since the thermal conductivity measurements were sensitive in detecting the difference in the formulation, it can be used as a tool to select a formulation that can best suit the processing conditions of the heat penetration tests. The technique described can be used for any thermal processes in the food industry including pasteurization, retort, and aseptic processing. This application will be beneficial for the industry to pre-screen the iterations and only select formulation that suits the scheduled process for successful heat penetration trials and reduce trial costs.</p>

Below-ground effects during forest fires are some of the important issues forest managers consider when conducting prescribed fire programs. Heat transfer models in soil are needed to predict temperatures in soil during forest fires. Many of the heat transfer models in soil that include the effects of moisture are complex and in most cases do not have very good predictive abilities. Researchers believe that simple heat transfer models in soil that neglect the effects of moisture could have very good predictive abilities.<p>This study presents a one-dimensional numerical model of heat transfer in dry homogenous sand. Both constant and temperature dependent thermal properties of the sand were used in order to determine which had better predictive abilities. The constant thermal properties model was also extended to a model of two-layer dry soil. A computer code written in Fortran was used to generate results from the model. A number of experiments were conducted with dry sand to validate the model. A comparison of the numerical and experimental results indicated that the temperature dependent properties model had better predictive abilities than the constant properties model. The models were found to do a good job of predicting temperature profiles and depth of lethal heat penetration at heat fluxes indicative of forest fires.<p>Experiments were also conducted to determine the effect of moisture on temperature profiles and the depth of lethal heat penetration in sand and the effect of inorganics on the spread rate of smoldering combustion in peat moss. An experimental correlation of the effects of inorganic content on the spread rate of smoldering combustion in peat moss was developed. Additionally, laboratory methods of validating models of heat transfer in soil were developed with the aim of limiting the dependence on full scale testing. Specifically the use of the cone calorimeter for validating numerical models of heat transfer in soil and the responses of forest floor soil and laboratory created soil samples to heat input were compared. The results indicated that the laboratory created soil did a very good job of mimicking the heat response of the forest floor soil with a maximum difference in lethal heat penetration of 4%.

Below-ground effects during forest fires are some of the important issues forest managers consider when conducting prescribed fire programs. Heat transfer models in soil are needed to predict temperatures in soil during forest fires. Many of the heat transfer models in soil that include the effects of moisture are complex and in most cases do not have very good predictive abilities. Researchers believe that simple heat transfer models in soil that neglect the effects of moisture could have very good predictive abilities.<p>This study presents a one-dimensional numerical model of heat transfer in dry homogenous sand. Both constant and temperature dependent thermal properties of the sand were used in order to determine which had better predictive abilities. The constant thermal properties model was also extended to a model of two-layer dry soil. A computer code written in Fortran was used to generate results from the model. A number of experiments were conducted with dry sand to validate the model. A comparison of the numerical and experimental results indicated that the temperature dependent properties model had better predictive abilities than the constant properties model. The models were found to do a good job of predicting temperature profiles and depth of lethal heat penetration at heat fluxes indicative of forest fires.<p>Experiments were also conducted to determine the effect of moisture on temperature profiles and the depth of lethal heat penetration in sand and the effect of inorganics on the spread rate of smoldering combustion in peat moss. An experimental correlation of the effects of inorganic content on the spread rate of smoldering combustion in peat moss was developed. Additionally, laboratory methods of validating models of heat transfer in soil were developed with the aim of limiting the dependence on full scale testing. Specifically the use of the cone calorimeter for validating numerical models of heat transfer in soil and the responses of forest floor soil and laboratory created soil samples to heat input were compared. The results indicated that the laboratory created soil did a very good job of mimicking the heat response of the forest floor soil with a maximum difference in lethal heat penetration of 4%.

Charcoal broiling is becoming an increasingly popular method for cooking meat. Little scientific work has been done in this area. Information presently available on charcoal broiling consists of broad generalizations which have developed from trial and error testing. With the current interest in charcoal broiling, there is a need for more factual, scientific information as to the proper procedure. Cooking method affects palatability and nutritive value of meat. Chemical and physical changes occur during the cooking process and the reactions which take place are not fully known or understood. Each cooking method has a specific effect upon meat due to the rate of heat penetration and the reactions which take place during the cooking period. Broiling usually takes place at high temperature, making this method of cooking meat contrary to recommendations . Generally broiling is done with the thermostat set at 500 F . The heating element is constantly energized when turned on. Attempts are made to adjust to the desired temperature by varying the distance from the heat source. Cover et al. (1957) showed actual surface temperature of the broiler often fluctuated from the desired temperature. Preliminary testing in our laboratory showed that it was impossible to regulate heat at a constant temperature with an electric broiler.

This theses deals with a structural design comparison of heat insulations implementation in flat roofs in light of heat engineering. It also adverts to possible structural design in terms of heat insulations distribution in a flat roof. There are many materials options. I show the possibilities of material solution and also advantages and disadvantages of the single sealing materials at these layers. In the aplication part of this thesis I deal with possible concepts of insulation and solution for a specific roof of an older apartment house in Brno, where I conducted a constructive exploration. There was developed and evaluated a few options of solutions considering the heat insulator used. The following computational programs were used for the evaluations: TEPLO, AREA, CUBE 3D.

The subject of this diploma thesis is the elaboration of the building project of Polyfunkční dům Sokolská 5. In the course of the diploma thesis is elaborated a summary technical report, report of building site and drawings for individual stages. The implementation of the waterproofing of the base structure and the reinforced concrete monolithic skeleton are subject to technological regulations and control and test plans. In this work the object time and financial plan, the use of machines and mechanisms and health and safety at work are also solved. For the main building objects, an item budget and a detailed schedule are prepared. Part of this work is also the calculation of the heat transfer through the envelope of the building.