Resumo em Inglês:

ABSTRACT Although dry bulb temperature (T) is the environmental variable most commonly used to classify thermal comfort in pigs, environmental assessment ratios provide more accurate information. The objective of this study was to correlate the sound pressure levels (SPL) produced by piglet vocalization with the thermal environment observed during the nursery phase, and subsequently establish thermoneutrality ranges. The experiment was conducted on a pig farm where T, relative humidity (RH), and SPL data were recorded between 9 am-5 pm for 42 days. The association between SPL and T in nursery phase piglets was verified; for thermal comfort to be possible, SPLs were 56.3 to 60.3 dB. The SPLs were subsequently used in predictor equations of ratios, and thermal comfort ranges were 74.4-78.3 for temperature and humidity ratio (THI), and 71.6-75.8 for globe temperature and humidity ratio (BGHI). Although the SPL proved to be a convenient indicator of thermal comfort for the evaluation of pigs, further studies developed in different phases of the production system are required.

Resumo em Inglês:

ABSTRACT The objective of this research was to analyze the differences between the food behaviors observed under the factors of production environment, sex and lighting system, using stochastic tools of multivariate analysis. As for the thermal characteristics of the environment, air temperature (T, °C), enthalpy (H, kJ kg-1), and black globe temperature and humidity index (BGTHI) showed high positive correlation with each other and strong negative correlation with relative humidity (RH, %). The “male drinking” behavior was positively associated with thermal characteristics of the environment in the three periods of the day, that is, the act of drinking more water would be a way to alleviate thermal stress. Birds subjected to red LED showed a strong negative correlation with temperature associated with the “female drinking” behavior, in the afternoon period, according to the principal component analysis, which is justified by the orientation of the broiler house with its longitudinal axis in the NE/SW direction, so the sunlight directly hits the area where the drinker was located. Variation in body weight showed better response when the birds were exposed to a temperature of 27 °C, for the 5th week of the rearing cycle.

Resumo em Inglês:

ABSTRACT This study aimed to identify whether there is an association between types of storage and categories of commercialization and use of grains, group the types of storage with the categories of commercialization, and group static and dynamic capacities of the units in the state of Paraná, Brazil. The data were obtained from the Brazilian Registry System of Storage Units for the 2014/2015 season. The association between variables under study was carried out with the chi-square test of independence and correspondence analysis. The cluster analysis consisted of the unweighted pair group method with arithmetic mean and considered a measure of mixed dissimilarity obtained for sets composed of qualitative and quantitative variables. A significant association was observed between the type of silo battery with the grain usage characteristic and cooperatives that commercialize the grain for use in the domestic market (CICOOPT); between the bulk warehouse and cooperatives that commercialize the grain in the foreign market (CIECOOPT); and between the silo and grain sellers who commercialize the grain in the domestic market (CI). Most types of storage units were grouped in Group 1, with a predominance of the CI characteristic and small to medium size static and dynamic capacity.

Resumo em Inglês:

ABSTRACT The use of nanoparticles appears to be a feasible option for improving the quality of a range of wood-based products. Studies show that they can improve both the physical and mechanical properties of wood and wood-based products. This preliminary study aimed to analyze the influence of SiO2 nanoparticles on the physical and mechanical properties of wood particleboard. To this end that, panels were produced without the addition of SiO2 nanoparticles and with the addition of 4% by mass of the urea formaldehyde adhesive used for its production. The results showed that panels produced with the nanoparticles 42% reduction in thickness swelling of the panel. Therefore, the dimensional stability of the panels without decreasing mechanical properties, even when used in small proportions.

Resumo em Inglês:

ABSTRACT An adequate thermal environment in pig farming facilities is essential to ensure productivity and animal welfare. The objective of this study was to evaluate the behavior and performance of finishing pigs, subjected to climate-controlled environments and supplementary lighting. Twenty-seven pigs (3/4 Duroc, 1/4 Pietrain) were kept in pens with no climate control, pens with forced ventilation and pens with adiabatic evaporative cooling system, associated with 12 h of natural light, 12 h of natural light + 4 h of artificial light and 12 h of natural light + 6 h of artificial light. The experimental design was completely randomized, in a 3x3 factorial arrangement and the means were compared by Tukey test (p<0.05). Meteorological variables, temperature and relative humidity, were recorded and the zootechnical performance of the animals was evaluated by weight gain, feed intake and feed conversion. Behavioral analysis was performed using the frequency of ingestive and comfort behaviors (exploratory activities and social interactions). Better performance was found for animals subjected to evaporative cooling, and the program with supplementary lighting for 6 hours promoted better feed conversion. Pigs subjected to evaporative cooling showed higher frequency of comfort behaviors and higher frequency of ingestive activity, stimulated by better thermal conditions in the housing.

Resumo em Inglês:

ABSTRACT Photovoltaic pumping systems equipped with variable speed drive have been consolidated as an alternative for water supply in rural locations where energy services are unavailable. Such systems are of the direct connection type and, therefore, it is likely that their operation occurs in two situations: when energy is available and when the reservoir is full or the available energy is insufficient for pumping water. Thus, this study aimed to evaluate the shared use of a photovoltaic pumping system equipped with a variable speed drive and the motor load of the agricultural equipment (cassava grater). The tests were performed in the laboratory and subsequently in the field, where data of the grated cassava production was collected in periods when the solar radiation is insufficient to pump the water. The results indicate that water can be pumped at an irradiance higher than 375 W m-2, while the cassava grater can operate at an irradiance starting from 200 W m-2. Thus, we could conclude that the agricultural equipment can be used in a photovoltaic pumping system equipped with a variable speed drive in a complementary way such that, besides optimizing the use of energy, it adds a new functionality to the application through the use of agricultural equipment.

Resumo em Inglês:

ABSTRACT This study aimed to assess the anaerobic digestion response of laying hen manure with different inclusion levels of biochar in batch reactors as measured by physicochemical parameters, biogas production and digestate quality. Four levels of biochar inclusions (0, 2.5, 5.0 and 7.5%) were tested with 3 replicates each. Twelve two-liter anaerobic batch reactors were used for 86 days at 35°C. Substrate and digestate of each treatment were assessed for monitored parameters, biogas production and digestate quality. Increased levels (0, 2.5, 5.0 and 7.5%) of biochar were found to gradually reduce total ammonia nitrogen (1794.33, 140.84, 950.81 and 509.32 mg.L-1, respectively). Despite the positive effect of biochar to accelerate initial biogas production, its use at any inclusion rate did not contribute significantly to biogas production in terms of biogas yield or digestate quality as compared to control treatment.

Resumo em Inglês:

ABSTRACT Monitoring of large agricultural lands is often hampered by data collection logistics at field level. To solve such a problem, remote sensing techniques have been used to estimate vegetation indices, which can subsidize crop management decision-making. Therefore, this study aimed to select vegetation indices to detect variability in irrigated corn crops. Data were collected in São Desidério, Bahia State (Brazil), using an OLI sensor (Operational Land Imager) embedded to a Landsat-8 satellite platform. Five corn growing plots under central pivot irrigation were assessed. The following vegetation indices were tested: NDVI (Normalized Difference Vegetation Index), EVI (Enhanced Vegetation Index), SAVI (Soil Adjusted Vegetation Index), GNDVI (Green Normalized Difference Vegetation Index), SR (Simple Ratio), NDWI (Normalized Difference Water Index), and MSI (Moisture Stress Index). Among the tested indices, SR was more sensitive to high corn biomass, while GNDVI, NDVI, EVI, and SAVI were more sensitive to low values. Overall, all indices were found to be concordant with each other, with high correlations among them. Despite this, the use of a set of these indices is advisable since some respond better to certain peculiarities than others.

Resumo em Inglês:

ABSTRACT Regionalization is an important technique for estimating the flow of hydrographic sections with a lack of data. First, it is necessary to identify hydrologically homogeneous regions (HHRs), which are commonly validated via statistical analyses. Because this step is understood to be subjective, studies that contribute to a greater reliability in identifying regions are needed. In this context, the objective was to evaluate the inclusion of a physical analysis of the average regionalized flow rates as an aid to identify HHRs. The groupings were defined on the basis of geographical convenience methods and cluster analysis. For the assessment of regionalized flows, six statistical indices were used with a physical analysis that was performed via a comparison of the runoff coefficient to the spatial distribution of precipitation values. It was concluded that the physical analysis reduced the subjectivity in the identification of HHRs.

Resumo em Inglês:

ABSTRACT Important losses of dwarf cashew seedlings during the establishment of orchards in the Brazilian semiarid are related to the relatively short rainy season. This study aimed to evaluate biochar and hydrophilic polymer as soil amendments to increase water retention and reduce plant death in the first year. An experiment was conducted at the Curu Station, Paraipaba, CE, Brazil, using the clone BRS 226. The experimental design consisted of randomized blocks, with amounts of 0.5, 1.0, 2.0, and 4.0 kg of cashew wood biochar and 20, 40, 60, 80 g of hydrophilic polymer applied per pit, as well as a control treatment (no soil amendment). Seedlings were submitted to an irrigation regime to avoid water stress (5 L water seedling−1 when the tensiometer installed at a depth of 0.15 m reached 60 kPa). The variables of plant development number of leaves, plant height, stem diameter, and canopy diameter were evaluated up to 374 days after transplanting to the field. The analysis of variance showed no treatment effect on plant development. However, minimum water consumption was observed when 29.56 g of hydrophilic polymer was applied per pit, providing 100.0% seedling survival.

Resumo em Inglês:

ABSTRACT Operational conditions of mechanized harvesting can affect the quality of harvested sugarcane. Therefore, the aim of this study was to assess the influence of the displacement speed and cutting height on the quality of the raw material during the mechanized harvest of sugarcane. Vegetable losses were accounted for in the field by manual collection of the fractions left after harvest. Vegetable and mineral impurities were determined at the processing stage in the laboratory. Both the displacement speed and cutting height did not affect vegetable losses. However, the increase in vegetal impurities occurred at higher displacement speeds, whereas lower cutting heights resulted in higher amounts of mineral impurities.

Resumo em Inglês:

ABSTRACT The hydraulic remote control system allows the transfer of energy from the engine through a flow of hydraulic oil to engines and implements pulled by agricultural tractors, which can interfere with its energy and operational performance. This study aimed to evaluate the interference of the number of remote control valves in use on the operational and energy performance of an agricultural tractor, using a productivity management system. The experiment was conducted in a strip-plot design, with five replications and three treatments, which consisted of the number of remote control valves in use (1, 2, or 3), totaling 15 experimental units. The results were subjected to normality and homogeneity tests and analysis of variance, followed by the Tukey test when it was significant. The highest number of valves in use interfered with the operational speed, power and efficiency on the drawbar, specific fuel consumption, and engine thermal efficiency, thus reducing the energy and operational performance of the agricultural tractor.

Resumo em Inglês:

ABSTRACT Draft and energy requirements are the most important factors in the activities of farm machinery management owing to their role in matching the tractor with implements for different tillage operations. This study's aim was to model the draft and energy requirements of a moldboard plow based on two novel variables. The first was the soil texture index (STI), which was formed from the clay, sand, and silt contents with a range of 0.03–0.84. The second variable was the field working index (FWI), formed by combining the plow width, plowing speed, soil bulk density, soil moisture content, plowing depth, and tractor power into one dimensionless variable, which had a range of 7.17–82.45. The coefficient of determination (R2) values obtained using a testing dataset were found out to be 0.9134 for energy and 0.8602 for draft requirements. For the draft and energy requirements of the testing data points, the mean absolute errors between the measured values and the values predicted using the artificial neural networks (ANN) model were 0.99 kN and 2.39 kW·h/ha, respectively. Based on comparisons with other results reported using multiple linear regression, it was clear that the predictions by the proposed ANN model were very satisfactory.

Resumo em Inglês:

ABSTRACT This study aimed to obtain and evaluate thermodynamic properties and hygroscopic equilibrium isotherms of urunday seeds as a function of air relative humidity and temperature, as well as identify the best-fitted mathematical models for adsorption phenomenon. A static-gravimetric method was used to obtain hygroscopic equilibrium moisture content. Seeds were placed in airtight containers with different saturated saline solutions for relative humidity control. These were then kept in BOD incubator chambers at 10, 20, 30, and 40 °C. Hygroscopic equilibrium moisture content decreased as temperature increased, for the same water activity. The Sigma-Copace model best-fitted seed adsorption data for equilibrium water activity intervals between 0.1129 and 0.8232 (dry basis). Both vaporization latent-heat and differential sorption entropy increased with decreasing hygroscopic equilibrium moisture content. Adsorption process in urunday seeds was controlled by enthalpy.

Resumo em Inglês:

ABSTRACT One of the factors that hinder the usability of Cerrado fruits is their perishable nature, requiring industrial processing to ensure prolonged shelf life. This study aims to determine the optimal foaming agent for industrial processing of this fruit, and to evaluate the physicochemical characteristics and antioxidant activity of dried cagaita powder (Eugenia dysenterica DC) in foam layers at temperatures of 40, 50, 60, and 70 °C. The effectiveness of three foaming agents at various concentrations were tested, and suitable agents were identified based on a factorial analysis of density, expansion, and stability. The physicochemical characteristics of the powder, along with its vitamin A and C and total carotenoid content and antioxidant activity, were evaluated. Vitamin C levels and antioxidant activity decreased with increasing temperature, but were retained at levels significant enough to establish cagaita as an important source of this vitamin. Higher carotenoid and vitamin A concentrations were found in the powder prepared by drying at 60 and 70 °C. The foam layer drying process employed for processing cagaita pulp reported here proved suitable for maintaining desired physicochemical and bioactive qualities in the final powdered product.

Resumo em Inglês:

ABSTRACT Guava is a fruit that stands out for its aroma, intense flavor, vitamins, and minerals. Its availability as a powdered food enhances its commercial applications. This study aimed to evaluate mathematical models for adsorption isotherms and determine the properties and flowability of guava pulp powder obtained by foam-mat drying. The models of GAB, BET, Henderson and Oswin were fitted to determine the isotherms of powders with 4 and 8% albumin, at temperatures of 35°C and 45°C. The powders were evaluated by wall friction angle, flow index, apparent density, and particle microstructure analysis. The best fit to the isotherms was obtained by the GAB model. Wall friction angle ranged from 15.7 to 21.9° and from 13.6 to 20.4° for samples containing 4 and 8% albumin, respectively. Higher densities were observed in the powder containing 8% albumin. The powders were classified as easy flowing when the flow index was between 8.00 and 8.68. The presence of albumin in powders resulted in particles with less rough surfaces, less hygroscopicity, and improved flowability.

Resumo em Inglês:

ABSTRACT Pig farming stands out as an alternative for decentralized electrical energy production from the use of biogas energy. However, its use is still limited. Thus, this study aimed to estimate and map the biogas production, as well as determine the electric power originated by the use of biogas produced in covered lagoon biodigester from pig farms of different sizes in the state of Minas Gerais, Brazil. The research was based on data provided by the Instituto Mineiro de Agropecuária (IMA). Three forms of electric power were estimated, as follows: (i) total, (ii) current, and (iii) installed. They were estimated from the volume of manure generated at each development stage of the animals. The total electric power corresponded to 31 MW, while the current electric power was equal to 20 MW. The installed electric power was still low and corresponded to 35.4% of the current electric power. The results showed that 55% of the current electric power was concentrated in only two mesoregions (Triângulo Mineiro/Alto Paranaíba and Zona da Mata). Therefore, the use of biogas contributed to providing energy self-sufficiency in pig farms and the generation of decentralized electrical energy.

Resumo em Inglês:

ABSTRACT This study used spectral data integrated with the agrometeorological model by Doorenbos and Kassam to estimate soybean grain productivity in the state of Mato Grosso, Brazil. In the developed model, spectral data were used instead of meteorological data and biophysical parameters of the crop. For this purpose, the products of real and potential evapotranspiration (MOD16), normalized difference vegetation index – NDVI (MOD13Q1), and leaf area index (MOD15A2H) from the MODIS satellite were used, in addition to sunstroke data obtained by using the visible channel from the satellite GOES IMAGER. The results obtained showed that, with the proposed methodology, it was possible to follow the development of soybean cultivation throughout the cycle and to estimate production and productivity in the study area. Willmott's agreement index was 0.99 and 0.96 and Pearson's correlation coefficient was 0.99 and 0.84 for production and productivity, respectively.