Predicting Thermoelectric Power Plants Diesel/Heavy Fuel Oil Engine Fuel Consumption Using Univariate Forecasting and XGBoost Machine Learning Models

Monitoring and controlling thermoelectric power plants (TPPs) operational parameters have become essential to ensure system reliability, especially in emergencies. Due to system complexity, operating parameters control is often performed based on technical know-how and simplified analytical models that can result in limited observations. An alternative to this task is using time series forecasting methods that seek to generalize system characteristics based on past information. However, the analysis of these techniques on large diesel/HFO engines used in Brazilian power plants under the dispatch regime has not yet been well-explored. Therefore, given the complex characteristics of engine fuel consumption during power generation, this work aimed to investigate patterns generalization abilities when linear and nonlinear univariate forecasting models are used on a representative database related to an engine-driven generator used in a TPP located in Pernambuco, Brazil. Fuel consumption predictions based on artificial neural networks were directly compared to XGBoost regressor adaptation to perform this task as an alternative with lower computational cost. AR and ARIMA linear models were applied as a benchmark, and the PSO optimizer was used as an alternative during model adjustment. In summary, it was possible to observe that AR and ARIMA-PSO had similar performances in operations and lower error distributions during full-load power output with normal error frequency distribution of −0.03 ± 3.55 and 0.03 ± 3.78 kg/h, respectively. Despite their similarities, ARIMA-PSO achieved better adherence in capturing load adjustment periods. On the other hand, the nonlinear approaches NAR and XGBoost showed significantly better performance, achieving mean absolute error reductions of 42.37% and 30.30%, respectively, when compared with the best linear model. XGBoost modeling was 8.7 times computationally faster than NAR during training. The nonlinear models were better at capturing disturbances related to fuel consumption ramp, shut-down, and sudden fluctuations steps, despite being inferior in forecasting at full-load, especially XGBoost due to its high sensitivity with slight fuel consumption variations

Phytochemistry of the genus Selaginella (Selaginellaceae).

The Selaginellaceae family includes the single genus Selaginella, which is found worldwide and comprises approximately 700 to 750 species. A number of species have been traditionally used for medicinal purposes in the whole world, and the phytochemistry of some has been investigated. For this review, the search was carried out using Web of Sciences, Chemical Abstracts and the data bank NAPRALERT (acronym for NAtural PRoducts ALERT), updated to October 2012. The references found in the search were then studied in detail. This review refers to 32 species and 130 compounds isolated from plants of the genus Selaginella, which are classified in appropriate chemical groups. The compounds isolated have been identified belonging to the classes of alkaloids, benzenoids, carbohydrates, chromones, coumarins, flavonoids, lignans, oxygen heterocycle, phenylpropanoids, pigments, quinoids and steroids. Some aspects of bioactivity of the secondary metabolites produced are discussed. For this purpose 75 references were consulted. Key words: Selaginellaceae, Selaginella, phytochemistry, review

OBTAINING TEMPERATURE FIELDS AS A FUNCTION OF EFFICIENCY IN TIG WELDING BY NUMERICAL MODELING

The temperature field serves as the basis for predicting levels of residual stress in a welded joint. The aspects related to the mathematical modeling of complex welding procedures were pondered with the FEM: variations in the physical and mechanical properties of the materials as a function of the temperature, the transience and the speed of the welding process, the material phase transformations, the different mechanisms of heat exchange with the environment (convection and radiation), all them associated with a high level of nonlinearity. The heat source used in this analytical model for heat supply was the double ellipsoid model proposed by Goldak (2005), in which a 60 mm x 50 mm and 3 mm rectangular ASTM AH36 steel plate was used for the TIG process simulations. It was made a comparison of temperature fields for three different values of process efficiency (60%, 70% and 80%). The results showed many differences in the temperature fields following changes in the levels of residual stresses which will be determined in further studies

Avaliação do potencial das terras do município de Aliança - PE para uso com irrigação.

O presente estudo foi realizado com o objetivo de avaliar o potencial das terras para irrigação no município de Aliança (PE), Microrregião da Mata Setentrional, numa área de 274,78 km2. Para isso foi usado o ?sistema de avaliação da aptidão agrícola das terras e a metodologia de ?classes de terra para irrigação?. Inicialmente foram adquiridas cartas plani-altimétricas, escala 1:25.000 e com curvas de nível equidistantes em 10 metros, utilizadas como material básico. O município possuem 2.118 ha de terras para uso com irrigação e englobam áreas aráveis situadas em relevo plano e suave ondulado. A maioria das terras, 25.360 ha, tem fortes restrições ao uso com irrigação, tendo como principais limitações a profundidade do solo, a fertilidade, a declividade, a sodicidade e ou salinidade, a drenagem e o lençol freático elevado. Assim, deverá ser estabelecido um planejamento estratégico sobre a viabilidade de uso racional dos recursos naturais disponíveis

Georreferenciamento e banco de dados de árvores matrizes de espécies da caatinga.

Objetivou-se, georreferenciarno campo, os potenciais matrizeiros que fornecerãosementes para a propagação de espécies nativas, bem como a elaboração de um banco de dados com suas informações botânicas

Características físicas e morfológicas do sêmen de touros da raça nelore confinados e tratados com somatotrofina bovina recombinante (r-bST).

Edição dos resumos da 20. Reunião Anual da Sociedade Brasileira de Tecnologia de Embriões, Araxá, MG, agosto 2006

Progesterona plasmática e fertilidade de fêmeas caprinas submetidas à sincronização do estro com prostaglandina F2?.

Resumo: Avaliou-se a resposta ao protocolo de sincronização do estro com duas doses de prostaglandina F2 (22,5µg) intervaladas de 10 dias, por meio da mensuração da concentração de progesterona plasmática, bem como a taxa de concepção das cabras após a inseminação artificial, de acordo com as diferentes respostas obtidas. Utilizaram-se 23 fêmeas e dois reprodutores da raça Toggenburg. A mensuração da progesterona plasmática foi realizada no dia da primeira aplicação de PGF2? (D0), no D5, no dia da segunda aplicação de PGF2? (D10), no D15, no D20 e no D33. A resposta positiva à PGF2? foi determinada pela queda da concentração de progesterona a valores abaixo de 1,5ng/mL, mensurada nos dias cinco e 15. As fêmeas foram distribuídas em três grupos. O grupo I foi composto por fêmeas que responderam às duas aplicações; o grupo II por fêmeas que não responderam à primeira aplicação e responderam à segunda aplicação; e o grupo III por fêmeas que responderam à primeira aplicação e não responderam à segunda aplicação, foram inseminadas e não conceberam. A presença de um corpo lúteo funcional, no momento das aplicações, determinou a resposta ao protocolo. As diferentes respostas das fêmeas ao protocolo, grupo I e II, não influenciaram as taxas de concepção. Plasmatic progesterone and fertility of goats submitted at estrus synchronization with Prostaglandin F2?. Abstract: Plasmatic progesterone concentrations were evaluated during the synchronization protocol with two doses of 22.5µg of Prostaglandin F2?, 10-day interval, and the conception rate of females in accordance to the reply to the protocol. Twenty-three female goats and two sexually mature Toggenburg bucks were used. Blood was sampled on day 0 (1st PGF2? injection), and on the following days 5, 10 (2nd PGF2? injection), 15, 20, and 33. The positive reply to the PGF2? was determined when the progesterone concentrations fell to values below 1.5ng/mL at days 5 and 15. The females were divided in three groups: Group I: females that responded to the two PGF2? applications; Group II: females that responded only to the second application; Group III: females that responded the first application, did not respond to the second application, were inseminated but did not conceive. The presence of a functional corpus luteum at the moment of the applications determined the reply to the protocol. There was no difference in the conception rates between females that responded to the two PGF2? applications or responded only to the second application

Taxa de concepção de cabras inseminadas com sêmen caprino resfriado a 5°C, por 12 ou 24 horas, em meio diluidor à base de gema de ovo.

Avaliou-se a capacidade fecundante do sêmen caprino resfriado a 5°C, por 12 (TI) ou 24 horas (TII), em container especial. Para tanto, utilizaram-se 62 fêmeas e dois reprodutores (B1 e B2) da raça Toggenburg, distribuídos em um esquema fatorial 2x2 (dois reprodutores e dois períodos de estocagem do sêmen). Após a coleta, o sêmen foi diluído em Tris-frutose-gema de ovo a 2,5%, envasado em palhetas de 0,25mL, com 150x106 espermatozoides móveis e resfriado a 5oC. As fêmeas receberam duas doses de 22,5µg de PGF2a, em intervalos de 10 dias para a sincronização do estro. A partir da primeira aplicação de PGF2a, as fêmeas foram monitoradas para ocorrência de estro, três vezes ao dia. Realizou-se uma única inseminação, pela técnica de fixação da cérvice, 12 horas após o início do estro. A motilidade e o vigor, após 12 ou 24 horas de resfriamento, foram de 66,14±0,11% e 62,50±0,05%, e 3,46±0,61 e 3,27±0,50, respectivamente. Não houve influência (P>0,05) do reprodutor, nem do período de armazenamento do sêmen sobre a taxa de concepção das cabras, que foi de 49,1%. Conception rate of goats inseminated with semen cooled in egg yolk diluent at 5 degrees C, for 12 or 24 hours. Abstract: The fertilizing capacity of goat semen cooled in egg yolk diluent at 5 degrees C, for 12 or 24 hours was evaluated. Sixty-two Toggenburg does and two sexually mature Toggenburg bucks were used in a fatorial treatment combination (two bucks and two storage periods). The semen was diluted in 2.5% Tris-frutose-egg yolk; envased in 0.25mL plastic straws, with 150x10(6) mobile spermatozoa; and cooled at 5 degrees C for 12 or 24 hours. The females received two doses of 22.5 mu g of prostaglandine F2 alpha, at each 10-day intervals in order to synchronize the estrous. From the first PGF2 alpha injection, estrous occurrence was monitored three times per day. Only one insemination was used, using the cervix fixation method, 12 hours after the estrous onset. The means of motility and strength, 12 (TI) and 24 hours (TII) after semen cooling at 5 degrees C, were 66.14 +/- 0.11% and 62.50 +/- 0.05%, and 3.46 +/- 0.61 and 3.27 +/- 0.50, respectively. Neither the sire nor the period of semen influenced (P>0.05) the conception rate of the does, which was 49.1%