Effect of the chemical composition of fluid foods on the rate of fouling processing during sterilization / Efecto de la composición química de los alimentos líquidos sobre la tasa de procesamiento de la suciedad durante la esterilización

Background: This research was motivated by the determination of the sanitation schedule in the heat exchanger area for some products (milk, avocado juice, and orange juice), as well as the inconsistency of the results of previous studies related to the chemical composition of the fouling layer. Objectives: a) to test the effect of raw material composition on the chemical composition of the fouling layer. b) to test microbial growth's effect on fouling's chemical composition (protein). Methods: mathematical derivation of the formation process of Resistant Dirt Factor (Rd) in the form of an Equation; ANOVA was used to test the effect of the dependent variable (protein) and predictor (microbial). Results: a) The composition of the raw material strongly influences the chemical composition of the fouling layer; b) There is a strong effect between microbial growth and protein content as a fouling composition (p<0.05). Conclusion: A strong influence between microbial growth and the composition of the fouling layer (protein) can close the research gap related to the inconsistency of previous research results (fouling layer composition), so there is no prolonged debate

Antecedentes: Esta investigación fue motivada por la determinación del cronograma de sanitización en el área del intercambiador de calor para diferentes productos (leche, jugo de aguacate y jugo de naranja), así como la inconsistencia de los resultados de estudios previos relacionados con la composición química de la capa de suciedad. Objetivos: a) probar el efecto de la composición de la materia prima sobre la composición química de la capa de suciedad. b) probar el efecto del crecimiento microbiano en la composición química de la capa de suciedad (proteína). Método: etapas del proceso de formación del Factor de Suciedad Resistente (Rd) en forma de una ecuación; Se usó ANOVA para probar el efecto de la variable dependiente (proteína) y el predictor (microbiano). Resultados: a) La composición química de la capa de incrustación está fuertemente influenciada por la composición de la materia prima; b) Existe un fuerte efecto entre el crecimiento microbiano sobre el contenido de proteína como composición de ensuciamiento (p<0.05). Conclusión: Una fuerte influencia entre el crecimiento microbiano y la composición de la capa de incrustación (proteína) puede cerrar la brecha de investigación relacionada con la inconsistencia de los resultados de investigaciones anteriores (composición de la capa de incrustación) para que no haya un debate prolongado

Sustainable Energy Sources for the Future: A New Geothermal Heat Pump System for the Built Environment.

In the recent attempts to stimulate alternative energy sources for heating and cooling of buildings, emphasise has been put on utilisation of the ambient energy from ground source heat pump systems (GSHPs) and other renewable energy sources. Exploitation of renewable energy sources and particularly ground heat in buildings can significantly contribute towards reducing dependency on fossil fuels. Geothermal heat pumps (GSHPs), or direct expansion (DX) ground source heat pumps, are a highly efficient renewable energy technology, which uses the earth, groundwater or surface water as a heat source when operating in heating mode or as a heat sink when operating in a cooling mode. It is receiving increasing interest because of its potential to reduce primary energy consumption and thus reduce emissions of the greenhouse gases (GHGs). The main concept of this technology is that it utilises the lower temperature of the ground (approximately <32°C), which remains relatively stable throughout th e year, to provide space heating, cooling and domestic hot water inside the building area. The main goal of this study is to stimulate the uptake of the GSHPs. Recent attempts to stimulate alternative energy sources for heating and cooling of buildings has emphasised the utilisation of the ambient energy from ground source and other renewable energy sources. The purpose of this study, however, is to examine the means of reduction of energy consumption in buildings, identify GSHPs as an environmental friendly technology able to provide efficient utilisation of energy in the buildings sector, promote using GSHPs applications as an optimum means of heating and cooling, and to present typical applications and recent advances of the DX GSHPs. The study highlighted the potential energy saving that could be achieved through the use of ground energy sources. It also focuses on the optimisation and improvement of the operation conditions of the heat cycle and performance of the DX GSHP. It is concluded that the direct expansion of the GSHP, combined with the ground heat exchanger in foundation piles and the seasonal thermal energy storage from solar thermal collectors, is extendable to more comprehensive applications.

Rectal Temperature Maintenance Using a Heat Exchanger of Cardioplegic System in Cardiopulmonary Bypass Model for Rats / 대한흉부외과학회지

BACKGROUND: Small animal cardiopulmonary bypass (CPB) model would be a valuable tool for investigating pathophysiological and therapeutic strategies on bypass. The main advantages of a small animal model include the reduced cost and time, and the fact that it does not require a full scale operating environment. However the rat CPB models have a number of technical limitations. Effective maintenance and control of core temperature by a heat exchanger is among them. The purpose of this study is to comfirm the effect of rectal temperature maintenance using a heat exchanger of cardioplegia system in cardiopulmonary bypass model for rats. MATERIAL AND METHOD: The miniature circuit consisted of a reservoir, heat exchanger, membrane oxygenator, roller pump, and static priming volume was 40 cc. Ten male Sprague-Dawley rats (mean weight 530 gram) were divided into two groups, and heat exchanger (HE) group was subjected to CPB with HE from a cardioplegia system, and control group was subjected to CPB with warm water circulating around the reservoir. Partial CPB was conducted at a flow rate of 40 mg/kg/min for 20 min after venous cannulation (via the internal juglar vein) and arterial cannulation (via the femoral artery). Rectal temperature were measured after anesthetic induction, after cannulation, 5, 10, 15, 20 min after CPB. Arterial blood gas with hematocrit was also analysed, 5 and 15 min after CPB. RESULT: Rectal temperature change differed between the two groups (p<0.01). The temperatures of HE group were well maintained during CPB, whereas control group was under progressive hypothermia. Rectal temperature 20 min after CPB was 36.16+/-0.32 degrees C in the HE group and 34.22+/-0.36 degrees C in the control group. CONCLUSION: We comfirmed the effect of rectal temperature maintenance using a heat exchanger of cardioplegia system in cardiopulmonary bypass model for rats. This model would be a valuable tool for further use in hypothermic CPB experiment in rats.

Simulation Research on Performance of Condensing Heat Exchanger in Different Working Conditions / 航天医学与医学工程

Objective To provide a more accurate calculation method for design of condensing heat exchanger (CHX) through an in depth discussion about working conditions of the CHX commonly used in temperature and humidity control system of manned spacecraft.Methods With difference of the simplified configuration of CHX,a mathematical model was given.Specifically,the log-mean temperature difference (LMTD) method was used in dry conditions,while in wet conditions mass and energy conservation equations were used.The set of equations of the model were solved by using the shooting method provided by Matlab/Simulink program.Results The results of working conditions and the performance of heat transfer and dehumidification of CHX were determined.Analysis showed that the simulation model could evaluate performance of the CHX in different work conditions reasonably and the results were close to the physical phenomenon.Conclusion The simulation models are of significance for design and optimization of CHX both in manned spacecraft temperature and humidity control system and in aircraft environmental control system.