2 research outputs found
Forensic NMR metabolomics: one more arrow in the quiver
No full textIntroduction: NMR metabolomics is increasingly used in forensics, due to the possibility of investigating both endogenous metabolic profiles and exogenous molecules that may help to describe metabolic patterns and their modifications associated to specific conditions of forensic interest. Objectives: The aim of this work was to review the recent literature and depict the information provided by NMR metabolomics. Attention has been devoted to the identification of peculiar metabolic signatures and specific ante-mortem and post-mortem profiles or biomarkers related to different conditions of forensic concern, such as the identification of biological traces, the estimation of the time since death, and the exposure to drugs of abuse. Results and Conclusion: The results of the described studies highlight how forensics can benefit from NMR metabolomics by gaining additional information that may help to shed light in several forensic issues that still deserve to be further elucidated
Simulação semi-empírica de refrigeradores domésticos: [dissertação]
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnologico, Programa de Pós-graduação em Engenharia Mecânica, Florianópolis, 2009Neste trabalho desenvolveu-se um programa computacional para simular o comportamento de um refrigerador doméstico específico, operando tanto em regime permanente como transiente cíclico. O programa foi desenvolvido com base nos princípios fundamentais de conservação da massa, energia e quantidade de movimento. Parâmetros empíricos derivados de experimentos foram introduzidos nas equações fundamentais, como forma de diminuir a complexidade do modelo e fazê-lo reproduzir mais realisticamente as condições experimentais. A modelagem do programa foi realizada de natureza quase-transiente, o que significa que o sistema foi modelado em regime permanente e o gabinete em regime transiente. O modelo do sistema de refrigeração foi adaptado a partir de uma metodologia já existente na literatura. Já o modelo do gabinete tinha a função de estimar, com certa precisão, a carga térmica, a vazão de ar no interior dos compartimentos e suas inércias térmicas. Através das comparações realizadas mostrou-se que a estratégia adotada é capaz de reproduzir o consumo de energia do refrigerador com uma margem de erro de 10%. Embora os parâmetros empíricos foram modelados de forma específica ao objeto de estudo, o programa computacional foi também utilizado para verificar o impacto de alguns parâmetros de projeto sobre o desempenho do sistema. Finalmente, a análise de sensibilidade proposta mostrou que mediante a alteração de alguns parâmetros de projeto, o consumo de energia com o refrigerador em consideração poderia ser reduzido em 18,7%.In this work a computer program to simulate the thermodynamic performance of a specific household refrigerator, running both in steady-state and in cycling transient conditions, was developed. The computer program was developed based on the fundamentals principles of mass, energy and momentum conservation. Empirical parameters derived from experiments were included in the equations to reduce the model complexity and also to improve its performance. The refrigeration system was modeled in steady-state conditions while the cabinet was modeled following a transient approach. The entire model is therefore of a quasitransient nature. The refrigeration system model was adapted from a literature existing approach. Now, the cabinet model had the function to estimate the thermal load, the airflow and thermal capacitance with good accuracy. Through the comparisons carried out by the author it was shown that such a strategy is able to reproduce the energy consumption experimental data within an error band of ± 10%. Although the empirical parameters were modeled in specific way for the object of study, the model was also used to study the impact of some design parameters on the system performance. Finally, the proposed sensibility analysis showed that by changing some design parameters the refrigerator energy consumption can be reduced by 18.7%
