Navegando por Assunto "Temperatura"

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Acesso aberto (Open Access)
Análise do impacto das mudanças climáticas nas unidades de conservação dos manguezais amazônicos na Costa Atlântica Brasileira
(Universidade Federal do Pará, 2023-06-28) SOUSA, Marina Costa de; ANJOS, Luciano Jorge Serejo dos; http://lattes.cnpq.br/0244738999001686; https://orcid.org/0000-0002-3270-6679; SOUSA, Adriano Marlisom Leão de; http://lattes.cnpq.br/4371199443425884; https://orcid.org/0000-0002-2809-5318
The Amazonian mangroves are subject to various climate impacts, demanding conservation and adaptation actions. The objectives of this study are to assess the vulnerability of the Amazonian mangrove Protected Areas (PAs) to climate change, provide climate prediction data for the region, and analyze if the PAs are effectively fulfilling their role in protecting these ecosystems. To achieve these objectives, data from MapBiomas were used to delimit the mangrove area, data from the World Database on Protected Areas (WDPA) were used to identify the PAs within the mangroves, data from WorldClim were used to obtain information on mean annual temperature (BIO1) and accumulated precipitation (BIO12), and Above Ground Biomass (AGB) data were used. The processing was carried out using ArcGIS, QGIS, and RStudio software. The results revealed a trend of increasing temperature over time, while accumulated precipitation showed a decreasing trend across different scenarios and periods. These patterns indicate that protected mangroves may face a continuous increase in temperature and a reduction in precipitation by the end of the century. The higher temperature contributes to increased energy availability, playing a fundamental role in regulating evapotranspiration in mangrove forests. On the other hand, reduced precipitation has a negative impact on salinity, productivity, growth, and species diversity in mangroves. The study also assessed the PAs that protect mangrove forests in the Amazon region, along with Above Ground Biomass (AGB) representing the amount of carbon stored in trees. The results showed that 80.2% of the mangroves are included within PAs, with higher protection in the state of Maranhão, followed by Amapá and Pará. However, there was variation in AGB among the evaluated states, with an increase in Amapá and Pará and a decrease in Maranhão. It is crucial to implement more effective management and conservation measures to address the challenges posed by climate change in these coastal ecosystems.
Acesso aberto (Open Access)
Desenvolvimento de termocélulas nanoestruturadas do tipo em camadas e coplanar
(Universidade Federal do Pará, 2021-08-10) PINHEIRO, Paula Fabíola Pantoja; REIS, Marcos Allan Leite dos; http://lattes.cnpq.br/8252507933374637; https://orcid.org/0000-0003-2226-2653
Environmental problems accentuated by fires and fossil fuels reflect the need to develop more accurate environmental monitoring systems, as well as the reuse of waste heat in thermoelectric conversion in industrial processes. Thus, in this research, thermocells based on Buckypaper (BP) were developed in two arrangements: layered and coplanar. BP was produced by vacuum filtration of functionalized Carbon Nanotubes (f-CNTs) through a filter paper with 14 μm pores. Scanning Electron Microscopy showed a BP consisting of cellulose fibers impregnated with agglomerated f-CNTs. By measuring two-point, a BP tape (1.0 cm2) showed an electrical resistance of 0.92 kΩ at 300 K. When heated in the range of 300-337 K, the BP reduced on average 22.39% of its electrical resistance, characterized as a thermoresistor. In the layered thermocell, keeping the copper electrode at room temperature while the BP electrode (active area: 5.5 cm2 ) was thermally excited generated a thermoelectric power (α) of 26.33 mV/K for ΔT = 3.0 K. This result is superior to that reported in nanostructured thermoelectrochemical cells and is close to that obtained by commercial silicon. In the coplanar thermocell, the BP was connected between two copper electrodes that acted as hot and cold sides (cooled by a heatsink) and reached α = -0.06 mV/K for ΔT = 19 K. This result was inferior to that obtained for Bi2Te3 and superior to that obtained by a free-standing BP based on nitrogen-doped CNTs.
Acesso aberto (Open Access)
Estabilidade aeróbia, pH e dinâmica de desenvolvimento de microrganismos da cana-de-açúcar in natura hidrolisada com cal virgem
(Universidade Federal do Pará, 2011-04) DOMINGUES, Felipe Nogueira; OLIVEIRA, Mauro Dal Secco de; SIQUEIRA, Gustavo Rezende; ROTH, Anna Paula de Toledo Piza; SANTOS, Juliana dos; MOTA, Diego Azevedo
The objective of this work was to evaluate the effect of whitewash addition and the times after application on aerobic stability and growth of microorganisms (fungi and yeasts) in fresh sugarcane. It was used a completely randomized experimental design, with four replications. Aerobic stability (temperature) and the concentrations of yeast and fungus and pH were evaluated in a split-splot scheme with five doses of whitewash (0; 0.5; 1.0; 1.5 and 2.0%) and five times after treatment (0, 24, 48, 72 and 96 hours). There was a significant effect of doses of whitewash for all evaluated parameters. The sugarcane which was not treated with whitewash (0.0%) showed a break in stability at the shortest time interval. The pH values increased gradually according to the dose of whitewash applied and they decreased over time. There was a numerical increase on the counting of yeast until 72 hours after application of whitewash, regardless to the dose, and the values tended to stabilize in 96 hours after treatment. There was no significant effect of whitewash doses on fungi development. The use of whitewash is effective in yeast growth control and it also promotes aerobic stability in fresh sugar cane.
Acesso aberto (Open Access)
Identificação e caracterização das massas d´água da Plataforma Continental do Maranhão, durante os períodos seco (Novembro, 1997) e chuvoso (Junho 1999)
(Universidade Federal do Pará, 2007-10-26) PONTES, Paulo Henrique Parente; KAMPEL, Milton; http://lattes.cnpq.br/0063119667740811; EL-ROBRINI, Maâmar; http://lattes.cnpq.br/5707365981163429; https://orcid.org/0000-0001-7850-1217
The Maranhão Continental Shelf (MCS) between the mouths of Gurupi and Parnaíba rivers is 203 km wide on the occidental coast and 72 km from Tubarão Bay toward southeast. The Maranhão coast is distinct: there are Maranhenses Reentrances in the Northwest; the dunes coast in the eastern side, being separated by the Golfão Maranhense, where the Mearim river, whose discharge is about 770 m3/s, discharges its fresh water. Other small rivers like Gurupi, Maracaçumé, Turiaçu, Itapecuru and Parnaíba discharge fresh water on the shore. The parameters of temperature, salinity and density were used to identify and characterize the water masses during dry season (november, 1997) and rainy season (june, 1999) in order to study seasonal variability of the local water masses. Images of Sea SurfaceTemperature (SST) obtained from Advanced Very High Resolution Radiometer (AVHRR) from NOAA satellites were used to observe its variation and verify some oceanographic features. The time series of monthly averages of images from AVHRR Pathfinder of SST with 4 km resolution (from 1985 to 2001), obtained from Instituto Nacional de Pesquisas Espaciais (INPE), was used to study the temporal and spatial SST variability through the calculation of climatological mean and its monthly SST changes in three points of the MCS to see if there are substantial changes in the features of the MCS waters during El-Niño/La-Niña seasons, since those phenomena can provoke (or not) great changes in the superficial water masses and in the local circulation. During the dry season (1997), it was observed that only Tropical Water, which is a water mass occurred, proving that at this season the continental water does not act on the MCS. However, during rainy season (1999) there were Coastal Water, Mixture Water, Tropical Water and South Atlantic Central Water. The Coastal Water is a water mass that comes from the rivers that discharge in the MCS. Mixture Water is a mixture of oceanic and continental water. So the presence of these two masses in the MCS proves that continental water occurred in the field of study during that period. The MCS water masses have the following physical characteristics: (i) Tropical Water: salinity over 36, temperature between 26,6° and 28,7°C and density between 23 kg/m³ and 23,8 kg/m³, which during the dry season occurs since the surface until more than 60 m of depth, while during rainy season it only occurs 40 km from the coast, from the surface until deeper 60 m; (ii) Coastal Water: salinity under 33, temperature between 28° and 29,4°C and density between 19 kg/m³ and 21,4 kg/m³, it occurs along 10km from the coast being also found from the surface until 28 m; (iii) Mixture Water: has salinity values between 33 and 36, temperature between 25,8º and 28,75ºC and density between 21,8 kg/m3 and 23,8 kg/m3 , and can be observed until 60 km from the coast along surface until 60 m; (iv) South Atlantic Central Water has salinity between 35,6 and 36, temperature under 18ºC and density between 23,9 kg/m3 and 25,8 kg/m3 that can be found 31 km from the coast and over 50 m depth. In the MCS, the AVHRR/NOAA images has shown low variation the SST field over the MCS. In November, 1997 maximum SST variation was 2,5ºC (minimum of 27°C and maximum of 29,5ºC) almost the same data obtained in situ where the maximum of SST was 28,6°C and minimum of 27,1°C. In the images of june, 1999, the oscillation of this parameter was between 27° and 29°C, similar to the data obtained during the ocean cruse of the same year that were of 27,4°C (minimum) and 29,2ºC (maximum). The graphics of SST anomaly in three different geographical sites of the MCS show a slight SST anomaly oscillation during the 1997/98 El-Niño event. The SST anomaly is higher in the MCS during 1998, which is between this work’s oceanographic expeditions. Therefore there was no significant influence of this phenomenon on the water masses of the MCS temperature characteristics during the data acquisition period. The occurrence of different water masses in the MCS region is related mainly to the seasonality on the area of study, which presents larger estuarine influence during the rainy season and little or no influence during the dry period, as can be confirmed through the predominance of oceanic waters (Tropical Waters) during the dry period and the presence of coastal waters and mixture water in the rainy season, determining clearer water stratification.
Acesso aberto (Open Access)
Influence of temperature, concentration and shear rate on the rheological behavior of malay apple (Syzygium malaccense) juice
(Universidade Federal do Pará, 2016-06) SANTOS, Pedro Henrique; SILVA, Luiza Helena Meller da; RODRIGUES, Antonio Manoel da Cruz; SOUZA, José Antonio Ribeiro de
The aim of this study was to evaluate the rheological behavior of malay apple, a traditional Amazonian fruit with high bioactive properties, at different temperatures and soluble solids concentrations. The experiments were carried out in a Brookfield R/S Plus rheometer with concentric cylinders geometry. Power Law, Herschel-Bulkley, Mizrahi-Berk, and Sisko rheological models were fitted to the experimental data. The malay apple juice (pulp and skin) showed a pseudoplastic behavior for all temperatures and concentrations with flow behavior indexes lower than 1. The temperature effect on the samples’ apparent viscosity was analyzed by the Arrhenius equation. The activation energy increased with a decrease in the soluble solids concentration, showing that the lower the concentration, the greater the temperature influence on the apparent viscosity. The soluble solids effect was described by the exponential equation. The exponential factor increased with the temperature increasing, showing that the higher the temperature, the greater the effect of the soluble solids concentration on samples’ apparent viscosity. Finally, a triparametric mathematical model combining temperature, concentration, and shear rate was proposed aiming to evaluate its effects on the samples’ apparent viscosity and has accurately adjusted to the data with high correlation index R2.
Acesso aberto (Open Access)
Otimização da desidratação osmótica de filés de mapará (Hypophthalmus edentatus) através da metodologia de superfície de resposta
(2008-06) RIBEIRO, Suezilde da Conceição Amaral; PARK, Kil Jin; HUBINGER, Miriam Dupas; RIBEIRO, Carmelita de Fátima Amaral; ARAUJO, Eder Augusto Furtado; TOBINAGA, Satoshi
Osmotic dehydration of mapará fillets has been used as a pre-treatment before dehydration and refrigeration of food as a means of reducing product moisture content. The aim of this study was to optimize mass transfer occurring during osmotic dehydration of mapará using the response surface methodology. Osmotic dehydration was carried out following a 23 complete factorial design, with eight factorial, three central and six axial points, totalizing 17 assays, where the values of the dependent variables, weight loss (PP), water loss (PA), solid gain (GS), GS/PA and tiobarbituric acid (TBA), are a function of the independent variables, temperature, concentration of NaCl and immersion time. The statistic analysis, applied to the experimental data was carried out using the pure error and the residual SS. Applying the response surface methodology, the best condition of convergence of lower weight loss, greater water loss and lower salt gain corresponded to a sodium chloride concentration of 22%, temperature of 46 °C and time of 7 hours.
Acesso aberto (Open Access)
Regimes térmico e hídrico em solos sob ecossistemas naturais e área agrícola no Leste da Amazônia
(Universidade Federal do Pará, 2007-12-14) CARVALHO, Saulo Prado; SOUZA, José Ricardo Santos de; http://lattes.cnpq.br/2797414407717271
Soils temperature and moisture are variables whose knowledge is required to Determine the energy and water budgets in the biosphere. The thermal and hydric regimes of soils beneath each ecosystem, present considerable variations, according to their mineralogy, the local climate and vegetation. In this context, soil temperatures and moistures were measured under three ecosystems existing over the eastern portion of the Amazon Region, namely: native forest (Caxiuana's National Forest, 01° 42' 30" S and 51° 31' 45" W), pasture area (Soure, 00° 43' 25" S and 48° 30' 29" W) and cultivated area (Igarape-Acu, 01° 07' 59" S and 47° 36' 55" W). Field data at the forest and pasture sites were collected between December, 2001 and February, 2005; while at the cultivated area, the monitoring was limited to the August, 2003 to February, 2005, period. These observations of soil physical variables were analyzed taken into consideration the simultaneously measured meteorological variables such as the incoming solar radiation flux and pluviometric precipitation, which directly impacted the soil variables at each site selected for study. The soil temperatures were monitored by means of thermal sondes at 0.05, 0.2 and 0.5 m depths. Heat fluximeters, measured heat flux at 0.05 and 0.2 m depth levels. The upper 0.3 m soil layer bulk moisture was measured by double probe Time Domain Reflectometer (TDR) sondes at each site. Analyses were made, considering the soil responses during the local dry and rainy seasons at these three representative ecosystems of eastern Amazonia. Apparent thermal diffusivity estimates were made by the amplitude and phase methods, using the daily heating pulse propagation data in these soils. The results showed quite different values. However, the first approach seemed to be more reliable and suitable to numerical modeling. As expected, considering their small vegetation cover, the soil temperatures at the upper levels, presented larger variations at the pasture and cultivated sites. Unexpectedly, the temperatures at 0.5 m depth beneath the forest showed larger amplitude variations than at 0.2 and 0.05 m depths. The numerical modeling of time variations of temperature, as function of depth, for each soil was made through the harmonic method. The results showed that the first harmonic represented over 90% of the total variation of the observed daily pulse of temperature for the pasture and cultivated areas at 0.2 and 0.05 m depths. Similar performance of the modeling was observed for the forest at 0.05 and 0.20 m levels. The magnitude of heat fluxes beneath the pasture and cultivated sites reached values six times larger than those observed beneath the soil of the forest. The results also show that, for the upper 0.30 m layer of soils, the bulk moisture beneath the forest is larger than under the other ecosystems studied in this work. This result apparently is due to the forest's protection against the soils surface evaporation. An analysis of the seasonal and daily behavior of the soils temperature and moisture in response to the incoming solar radiation and precipitation are presented. Case studies of the rate of soil moisture losses after significant water recharge by precipitation events were also analyzed. Some estimates of daily water depletion and even, night recharge of moisture by rising water from lower layers to the 0.30 m layer were made. This work analyzed the largest time series of soil temperature and moisture data taken at high sampling rates, available so far, for eastern Amazonia. It was possible to characterize the differences of these physical variables regimes, beneath three important ecosystems in this Region. Further studies of the minerals and organic materials in these soils, as well as the foliar area and biomass indexes of their vegetation covers, would improve the comprehension of the regimes described in this work.
Acesso aberto (Open Access)
Relações econômica e climática na produção agrícola no leste do Pará.
(Universidade Federal do Pará, 2019-06-28) BAUTISTA LÉVANO, Diego Alonso; ROCHA, Edson José Paulino da; http://lattes.cnpq.br/2313369423727020
The present research related the average yields or productivity of the eight main crops located in municipalities in the east of Para. In the economic relation, it was worked with the dependent variable Gross agricultural value added (VAB.AGR) and the climatic relation was performed with the variables precipitation and temperature during 2002-2016. The selection of the eight crops was according to their percentage representation in the quantities produced during the study period. For this reason, the crops were divided into permanent (CP: banana, coconut palm, palm, and orange) and temporary (CT: sugar cane, cassava, corn, and soybean). The secondary data of the VAB.AGR, quantities produced (QP), average yields (Rm) or productivity and values of municipalities production were compiled in the portal of the Instituto Brasileiro de Geografia e Estatística (IBGE) and Produção Agrícola Mensal (PAM). Regarding the complexity of the climatic variables, the information of the Climate Prediction Center MORPHing technique (CMORPH) for the precipitations and the European Center for Medium-Range Weather Forecast (ECMWF) for the temperature data were researched and collected. The methodologies used were the Ordinary Least Squares (OLS) to know the level of association between the variables having as a dependent variable the GVA.AGR, as well as the Pearson Coefficient to know the degree of relationship between climatic variables and the QP and Rm. Finally, from the results obtained we can believe that the eight selected crops, at least one type of crop, is significant with the economic, and climatic development.
Acesso aberto (Open Access)
Rheological behavior of concentrated tucupi
(Universidade Federal do Pará, 2018-11) COSTA, Telma dos Santos; RODRIGUES, Antonio Manoel da Cruz; PENA, Rosinelson da Silva
Tucupi, which is widely enjoyed in the North region of Brazil, is a fermented liquid derived from cassava (Manihot esculenta Crantz) and has been taken abroad for its exotic characteristics. This study aimed to assess the rheological behavior of tucupi with 30, 35, and 40% solids and concentrated at 50, 70, and 90 °C. The rheological data were obtained at 25, 40, 60, and 80 °C with increasing and decreasing shear rates. Rheology at 25 °C indicated that the partial gelification of starch during concentration causes a decrease in the product’s viscosity and, if the concentration is carried out at a temperature that favors total starch gelification, the product’s viscosity increases. Concentrated tucupi behaved as a pseudoplastic fluid, but at 60 and 80 °C with increasing shear rates, the product behaved as a dilatant fluid. Hysteresis were observed in flow curves starting at 40 °C, which characterizes concentrated tucupi as a rheopectic fluid. The Ostwald-de Waele model predicted the product’s flow curves and an Arrhenius-like equation described the dependence of temperature on apparent viscosity for the rheological data obtained with increasing shear rates. The product’s activation energy (E a) values ranged from 16.86 to 25.23 kJ/mol as a function of concentration.
Acesso aberto (Open Access)
Variação interanual e sazonal das massas d’água sobre a Plataforma Continental Norte do Brasil
(Universidade Federal do Pará, 2021-12-20) MEDEIROS, Paula Renata Lobato de; ROSÁRIO, Renan Peixoto; http://lattes.cnpq.br/8003860457518342; https://orcid.org/0000-0003-2913-0514
This study aimed to analyze the spatial and temporal variability of water masses over the Northern Continental Shelf of Brazil (PCNB), relating it to local dynamics and freshwater inputs. The PCNB extends from Cape Orange to the Bay of São Marcos and is characterized as highly energetic, due to the combined action of the north current of Brazil (CNB), trade winds, waves, tides and the water discharge from the Amazon rivers and Pará. Temperature, salinity and density data for the interannual analysis were obtained from the Brazilian Navy's national database (BNDO), during six oceanographic cruises: Amasseds I, II and III, North Ocean I, MCT VII and CBO in different years: 1989, 1990, 2001, 2016 and for the seasonal analysis, five months of the Costa Norte Project were used: March, July, November, December 2018 and January 2019. The TS parameters were intended to characterize and identify the water masses that occurred on the platform over the years, as well as observe the existing interannual and seasonal variability. The PCNB showed large variations in TS over the years and periods analyzed, and it is possible to observe the occurrence of four types of water bodies interannually: Pluma Estuarina (PE), Coastal Water (AC), Central Water of the South Atlantic (ACAS) and Tropical Water (AT) and seasonally, five water bodies were identified as occurring: AF (front water), AC, AT, ACAS and Pluma etuarina (PE). From the analysis of the TS diagrams it was possible to identify a thermohaline index for the estuarine plume and its metrics over time, where it occurred in March - 2018 and January - 2019, and their respective thermohaline indices were 27.5 °C to 28 °C and 0 g/kg to 33 g/kg.