Análise das condições de utilização de permutadores de calor de modo a serem economicamente rentáveis

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Mecânica Perfil Energia, Refrigeração e ClimatizaçãoNeste trabalho pretende-se abordar alguns assuntos referentes à utilização de permutadores de calor em sistemas AVAC. Uma vez que os sistemas AVAC tratam o ar ambiente para depois o insuflar nos espaços climatizados, é importante abordar alguns componentes de psicrometria, como as propriedades psicrométricas e o diagrama psicrométrico. Posteriormente aborda-se a teoria dos permutadores de calor e apresenta -se os tipos mais utilizados em AVAC. A parte mais importante do trabalho consiste na criação de um algoritmo em Excel que permite, através da inserção de alguns dados, calcular a poupança anual obtida com a implementação de permutadores de calor e o tempo de amortização do investimento feito na aquisição do equipamento. Considerando o perfil de temperaturas horárias anuais de três cidades portuguesas (Bragança, Beja e Peniche), são feitos estudos,através do algoritmo, que permitem tirar algumas conclusões sobre a rentabilidade da utilização de PC em Portugal Continental. Finalmente, aborda-se um processo que possibilita uma melhoria da permuta de calor entre os caudais de ar presentes no PC e realiza-se um estudo para perceber qual o aumento da poupança anual com a aplicação do mesmo.Abstract: This work intends to address some issues concerning the use of heat exchangers in HVAC systems. It’s important to talk about psychrometric components like psychrometric properties and psychrometric chart once that the HVAC systems treat the dry air to inflate in the air-conditioning spaces. Later discusses the theory and the types of heat exchangers more used in HVAC. The most important part of this work consists in the creation of an algorithm in Excelthat allows, through the insertion of some data, calculate the annual savings achieved with the implementation of heat exchangers and the time of amortization of investment resulting from the acquisition of equipment. Considering the hourly temperature annualprofile of three Portuguese cities (Bragança, Beja e Peniche), some studies are made by means of this algorithm, which enables us to draw some conclusions about the profitability of using heat exchangers in Portugal Finally, we analyze a process that enables an improvement in the exchange of heat between the air flows inside the heat exchanger and performs a study to see the increase in annual savings due to the implementation of the process

Phytochemical study and evaluation of the antimicrobial activity and cytotoxicity of Cuscuta racemosa

Cuscuta racemosa Mart. is a parasitic plant of the Convolvulaceae family, used in popular medicine as an anti-inflammatory and a diuretic, for stomach and hepatic disorders, and for treating fresh wounds. This plant is popularly known as "cipó-chumbo" and "fios-de-ovos". In this study, it was chemically investigated and tested for its antimicrobial activity and cytotoxicity. The flavonoid and tannin content of the dried plant were 2.79% and 2.01%, respectively. Furthermore, the 4'-methoxyquercetin flavanoid compound was isolated from the ethanolic fraction. The minimum inhibiting concentration in the antimicrobial test was 2.0 mg/ml for Staphylococcus aureus, and a DL50 of 0.231 mg/mL was obtained in the cytotoxicity experiment. The fraction directed to alkaloids was able to eliminate 100% of the brine shrimp used for the test

Anti-Streptococcal activity of Brazilian Amazon Rain Forest plant extracts presents potential for preventive strategies against dental caries

Caries is a global public health problem, whose control requires the introduction of low-cost treatments, such as strong prevention strategies, minimally invasive techniques and chemical prevention agents. Nature plays an important role as a source of new antibacterial substances that can be used in the prevention of caries, and Brazil is the richest country in terms of biodiversity. OBJECTIVE: In this study, the disk diffusion method (DDM) was used to screen over 2,000 Brazilian Amazon plant extracts against Streptococcus mutans. MATERIAL AND METHODS: Seventeen active plant extracts were identified and fractionated. Extracts and their fractions, obtained by liquid-liquid partition, were tested in the DDM assay and in the microdilution broth assay (MBA) to determine their minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs). The extracts were also subjected to antioxidant analysis by thin layer chromatography. RESULTS: EB271, obtained from Casearia spruceana, showed significant activity against the bacterium in the DDM assay (20.67±0.52 mm), as did EB1129, obtained from Psychotria sp. (Rubiaceae) (15.04±2.29 mm). EB1493, obtained from Ipomoea alba, was the only extract to show strong activity against Streptococcus mutans (0.08 mg/mL<MIC<0.16 mg/mL; MBC=0.16 mg/mL) in the MBA. CONCLUSIONS: The active extracts, discovered in the Amazon rain forest, show potential as sources of new antibacterial agents for use as chemical coadjuvants in prevention strategies to treat caries

Alkaloids and biological activity of beribá (Annona hypoglauca)

ABSTRACT Annona hypoglauca Mart., Annonaceae, popularly known as &#8220;beribá&#8221;, was collected in flooded areas of the Amazonian Rain Forest. The crude extract obtained from this species was found to be cytotoxic against human cancer cells. Chemical information on A. hypoglauca is scarce. So, the present work aimed the isolation and identification of its alkaloids and to test their cytotoxic activity. Alkaloids were obtained from stem by acid&#8211;base partitioning and the remaining alkaloid-free extract was partitioned with organic solvents. Gas chromatography&#8211;mass spectrometry GC/MS analysis of total alkaloids allowed the identification of four aporphine alkaloids: actinodaphnine, anonaine, isoboldine and nornuciferine. Total alkaloids were fractionated by column chromatography and were purified by preparative thin-layer-chromatography, which allowed the isolation of two aporphine alkaloids, actinodaphnine and isoboldine, characterized by NMR and CG&#8211;MS analyses. This is the first report for the occurrence of actinodaphnine in Annona species. All the samples were tested in cytotoxic and antibacterial assays. Total alkaloid extract and its fractions showed antimicrobial activity against Staphylococcus aureus and Enterococcus faecalis. In the cytotoxicity assay, the crude extract showed a lethal effect against breast and colon cancer cells. Isoboldine-containing FA5 and actinodaphnine-containing FA6 showed activity against breast cancer cell line, while the alkaloid-free fractions did not show significant activity against cancer cell lines

Isolamento e avaliação da atividade biológica dos alcalóides majoritários de Tabernaemontana angulata Mart. ex Müll. Arg., Apocynaceae

"Isolation and evaluation of the biological activity related to the major alkaloids in Tabernaemontana angulata Mart. ex Mull Arg., Apocynaceae." Introducing-new chemotherapeutic agents is a, great demand. in the control of infections diseases.' Brazil is one of the richest countries in biodiversity and the Laboratorio de Extracao at UNIP has been collecting plants from. the Amazon and Atlantic Rain Forests with the aim of screening for new antibacterial and antitumor plant extracts. Previous studies demonstrated that the ethanol fraction obtained from the crude extract of Tabernaemontana angulata stems showed antibacterial activity against Staphylococcus aureus (ATCC 6538 in the microdilution broth assay. Two alkaloids were the major compounds in the active fraction, verified by thin layer chromatography analysis. In the present study, the total alkaloids were obtained from the crude extract and were fractionated by preparative thin layer chromatography for the isolation of the main components. The isolated. compounds were identified by GC/MS and (1)H-NMR as coronaridine,e and voacangine. The alkaloid fractions obtained from the isolation procedure were tested for antibacterial activity, but no activity was detected