Resumo em Inglês:

ABSTRACT Adobe is an efficient construction material for several reasons, such as its thermal comfort, sustainability, and lower energy cost, as well as the simplicity of its production and execution. However, challenges such as water absorption, capillarity, and compressive strength should be investigated to improve its physical and mechanical properties. “Synthetic termite saliva” (STS) is an excellent stabilizer with high cohesive and hydrophobic power. Therefore, the objective of this work was to evaluate the effects of STS incorporation into adobe, analyzing its physical, mechanical and thermal properties. Five treatments were studied: 0 (control); 0.1; 0.2; 0.4 and 0.8% STS by mass. These adobe samples were evaluated according to bulk density, linear shrinkage, capillarity, water absorption, thermal conductivity and compressive strength, according to Norma Técnica de Edificación (NTE) E0.80 testing using a new methodology. Linear shrinkage decreases from 2.7 to 1.91 cm with 0.4% STS. Capillarity decreases with the increasing amounts of STS. Water absorption decreased from 12.03 to 6.31% using 0.4% STS, and its mass was reduced from 779 to 19 grams. The thermal conductivity showed no differences between concentrations. The compressive strength was reduced but was still acceptable based on NTE E.080. The stabilization of the adobe using STS showed an improvement in its physical properties, mainly due to its hydrophobic power.

Resumo em Inglês:

ABSTRACT This research aims to improve the study about the stability of truss structures used in pivot irrigation, widely used due to the growing demand for food production, when submitted to wind effects. Specifically, it aims to verify the maximum wind speed supported by an irrigation center pivot structure when submitted to the load effects caused by wind gusts perpendicular to the equipment. In order to determine these forces and their effects on the irrigation equipment, computational numerical investigations were carried out using finite element bar models validated by measuring the natural frequency of the equipment in the field. A span was designed based on the existing standards in Brazil and the dynamic response of the structure was examined under the effects of wind gusts. Models of the Brazilian standard NBR 6123/88 for structures submitted to wind effects were used in this study. The studied irrigation equipment supports wind gusts of up to 115 km/h applied perpendicularly, with a duration of 3 s, before generating toppling.

Resumo em Inglês:

ABSTRACT In the production of glue-laminated timber (GLT), boards derived from planted forest wood with easy workability are glued on top of one another. The main objective of the present work was to evaluate the performance of paricá timber GLT beams (5 × 10 cm) on GLT. Three procedures were performed: (1) GLT beams (5 × 10 cm) were produced using natural lamellae without chemical preservatives; (2) the individual lamellae (2.5 × 5 cm) were chemically treated, and then glued together; and (3) the beams formed from the glued natural lamellae (5 × 10 cm) were treated chemically. The positions of lamellae on the beams were determined by their modulus of elasticity values (MOE), which were estimated by a non-destructive bending test with a three-point load. The analytical bends, determined by the homogenized section method, and the experimental bends, measured by the four-point bending test, were compared. The differences between the bends were statistically evaluated, and it was found that the experimental bend (21.65 mm) was less than the analytical bend (34.02 mm). There was no significant loss of shear strength or MOE. The axial strength of the chemically untreated beams (49.18 MPa) was significantly higher than that of the untreated beams fabricated from natural lamellae (40.48 MPa). The results indicate that the gluing of treated lamellae does not affect beam performance.

Resumo em Inglês:

ABSTRACT This study aimed to evaluate the effect of wood shaving bedding on pregnant sows under two housing conditions. Sixty-four animals were distributed into four treatments, each treatment included 54 sows split into three replicates. A 2 × 2 factorial design was used (two types of housing, collective pens (CP) and combined housing (cages + CP [CCP]); and two types of floor, concrete floor without wood shavings (CFWS-) and concrete floor with wood shavings (CFWS+), allowing establishing the following treatment combinations: CP+CFWS+, CP+CFWS-, CCP+CFWS+, and CCP+CFWS-. Animal behavior, body injuries, reproductive efficiency, and abiotic variables were evaluated. The sows kept on wood shaving bedding presented a higher frequency of standing postures (20.9% and 31.4% for CCP+CFWS- and CCCP+CFWS+ and 20.6% and 39.2% for CP+CFWS- and CP+CFWS+, respectively). The presence of bedding decreased the occurrence of oral stereotypies and the frequency of injuries in the head, neck/shoulder, and side (12.30% and 6.02% for CCP+CFWS- and CCCP+CFWS+, and 8.07% and 5.69% for CP+CFWS- and CP+CFWS+, respectively). The treatments had no effect on stillbirth rates and on the number of piglets born alive, and the number of mummified piglets was higher in CP+CFWS+ than in was in CCP+CFWS-. However, the presence of bedding changed animal activity and decreased the incidence of injuries.

Resumo em Inglês:

ABSTRACT Biofortified sweet potato (Ipomoea batatas) is one of the foods with the highest contributions of carotenoids in the diet, especially provitamin A carotenoids. Thus, this study aimed to analyze the drying kinetics of the biofortified sweet potato pulp using the Akaike (AIC) and Schwarz's Bayesian (BIC) information criteria for model selection, as well as determine the effective diffusion coefficient and activation energy under different drying conditions. The biofortified sweet potatoes were sliced into chips and submitted to drying in an air circulation oven at 1.0 m s−1 at temperatures of 45, 55, 65, and 75 °C until constant mass. The mathematical models Wang and Singh, Verma, Thompson, Page, Newton, Midilli et al., logarithmic, Henderson and Pabis, two-term exponential, two-term, diffusion approach, frequently used to predict the drying of vegetal products, were adjusted to the data. The Wang and Singh model was selected to represent the drying of the biofortified sweet potato pulp by exhibiting the best adjustment for most conditions. The AIC and BIC criteria were suitable for selecting the Wang and Singh model. The effective diffusion coefficient increased as drying air temperature increase and the activation energy for liquid diffusion was 29.18 kJ mol−1.

Resumo em Inglês:

ABSTRACT In radish production, the choice of proper genotypes and irrigation regime is of great importance to achieve success. In light of this, the current study aimed to evaluate the agronomic performance of a few radish genotypes under different irrigation strategies. The plants were grown in the city of Unaí - MG, in Brazil, under field conditions, and during two cycles, one of 40 days (from February 28 to April 8, 2015) and other of 51 days (from May 9 to June 28, 2015). The experimental design was a randomized block design in a split-plot arrangement with four replications. The treatments consisted of four irrigation strategies (50, 75, 100, and 125% of crop evapotranspiration - ETc) applied by a dripping irrigation system, while subplots consisted of three radish cultivars (Comet, Saxa, and Crimson Giant). We evaluated the following parameters: root system depth, leaf chlorophyll content, shoot fresh matter, diameter and length of tuberous root, number, and mass of commercial and non-commercial tuberous roots, and water use efficiency. All the radish genotypes showed no differences for agronomic characteristics. Under Brazilian Cerrado conditions, the most suitable irrigation strategy for radish crops is 100% of ETc.

Resumo em Inglês:

ABSTRACT One of the limitations to producing irrigated forages is setting suitable biometric parameters to establish the entrance of animals to grazing areas. Such parameters can be measured or even estimated. Estimates are advantageous for being practical and able to be used for grazing optimization. This study aimed to evaluate the correlation among growing degree-days (GDD), canopy height (CH), leaf area index (LAI), and number of cycle days (NCD) of Guinea grass (Panicum maximum cv. Mombaça) and Bermuda grass (Cynodon spp. Tifton 85) single cropped for one year and overseeded with black oat and ryegrass in the autumn-winter season. The study was carried out from February 2016 to February 2017, and forage crops were sprinkle irrigated. LAI and CH were measured twice a week, at intervals of 3 and 4 days. These parameters were correlated to GDD accumulation at each cutting cycle (CC). All the correlations showed high coefficients in linear fits. For spring-summer cycles, Guinea grass in exclusive cultivation showed the highest averages for CH and LAI, being 102.3 cm and 5.93, respectively. For autumn- winter cycles, when this grass was overseeded, it showed an LAI value similar to that when single cropped, which was of about 5.6. Yet single Bermuda grass presented lower values of LAI (one unit lower) and CH (16.4 cm lower) in the autumn-winter season when compared to that overseeded. The spring-summer cycles of Guinea grass had a duration of 24 days, after which no increase in leaf production was registered.

Resumo em Inglês:

ABSTRACT Maintaining homogeneity in the distribution of fungicidal sprays applied throughout the plant, minimizing the variation between the upper and lower third of the plant, is one of the main challenges for application technologies with regard to soybean crops. To increase the deposition and leaf coverage of sprayed compounds, especially in the middle and lower thirds of the plant, we developed and tested alternative assisted boom sprayer systems. In this study, three assisted boom sprayer systems (Vortex®, Dropleg®, and chain curtain) were evaluated, in addition to the conventional system, in terms of the deposition and coverage of the leaf surface they achieved in the upper, middle, and lower thirds of plants using the fluorescent tracer Helios SC 500™. The assisted boom sprayer systems allowed the sprayed mixture to be better distributed throughout the plant. With the conventional spray system (without assitance), the deposition in the upper third was approximately 26 times higher than that in the lower third, whereas with the use of the assisted boom sprayer systems, the difference in deposition between these thirds was 11 times higher. Among the evaluated systems, the Dropleg® system presented the lowest depositional variation, which was only 5.5 times higher in the upper than in the lower third, because of the increased deposition achieved in the lower third of the plant. Leaf coverage varied from 41% to 81% in the upper third, from 24% to 43% in the middle third, and from 4% to 13% in the lower third of the plant. Using the conventional spray system, the leaf surface coverage was approximately 13 times higher in the upper third than in the lower third of the plant, whereas with the use of the assisted boom sprayer systems, especially the Dropleg® system, this variation was reduced by 73%, and the coverage of the upper and lower thirds only differed by 3.5 times. Indeed, the Dropleg® system reached a leaf coverage of close to 13% in the lower third of the plant. The use of assisted boom sprayer systems improved the distribution of the mixture applied throughout the plant, reducing the differences among the thirds of the plant both in the levels of deposition and coverage of the leaf surfaces. The Dropleg® system increased the deposition and leaf coverage in the lower third of the plant the most, facilitating better distribution of the mixture.

Resumo em Inglês:

ABSTRACT Work in the field is characterized as unstructured because it is performed in inconvenient postures, without a fixed workstation, exposing the worker directly to the sun and other inclement weather. This may interfere in the health and the performance of the activity. The objective of this work was to characterize the environment of the agricultural microtractor operator, evaluating the thermal comfort during the activity in the municipality of Quixadá, CE. A model TC14 Super Yanmar Agritech microtractor, coupled to a rotary spindle, was used. For the measurements of the environmental variables, sensors and devices were installed on the operator and in the microtractor. The experimental design adopted the assumptions of statistical quality control. Fifteen collections were done daily at different times for three consecutive days. The data obtained were indices of thermal discomfort and thermography, both of which were analyzed by sequential graphs (run charts), control graph (Xbar-R chart), and scatter plot. At all rates, the work performed proved to be inadequate, exceeding the operator's capabilities and limitations. It was concluded that the activity performed by the microtractor operator is stressful. Measures should be taken to improve working conditions without affecting the operator's health.

Resumo em Inglês:

ABSTRACT Machine traffic and conventional tillage can cause structural degradation of the soil, affecting the physical attributes and, consequently, the production and longevity of the sugarcane field. The objective of this study was to evaluate the production components of sugarcane cultivars (RB965902, RB985476, RB966928, RB855156, RB975201, RB975242, RB036066 and RB855536) and physical attributes of a Dystroferric Red Latosol (Oxisol) under no-tillage and reduced-tillage systems. The experiment was conducted using a completely randomized experimental design in an 8 × 2 factorial arrangement, with four replicates. The soil attributes evaluated were density, total porosity, macroporosity, microporosity and penetration resistance. The production components evaluated were stalk length and diameter, number of tillers (NT), tons of cane per hectare (TCH), sucrose content (Pol), tons of sucrose per hectare (TPH), soluble solids content (Brix), total recoverable sugars (TRS) and plant fiber. Cultivars RB965902, RB966928, RB855156 and RB985476 have productivity and technological attributes that are superior to the other cultivars, whereas these are lower for RB036066 in both soil tillage systems. Cultivars RB966928, RB855156, RB975242 and RB855536 exhibited higher TCH and TPH in the no-tillage system, and all cultivars displayed equal or higher performances than those observed in the reduced-tillage system. In the no-tillage system, which exhibits lower penetration resistance values between wheel tracks and in the subsurface layer of the planting row (0.20–0.40 m), cultivars RB985476 and RB975242 had a higher NT, and RB855156 had higher stalk lengths and NT.

Resumo em Inglês:

ABSTRACT Brazil is the largest sugarcane producer worldwide. In mills, sugarcane crops are sprayed with agrochemicals using self-propelled, tractor-driven, and aerial hydraulic sprayers. As sugarcane spraying is regularly performed over extensive areas, the machinery to be used should be planned and dimensioned to ensure timely operations without overloading and at lower costs. Therefore, the current study aimed to analyze the operational and economic performances of different hydraulic sprayers to perform sugarcane crop control. As long as meeting our goal in field conditions would be difficult, we opted to develop a computational model, named as “TratoCana”, using a spreadsheet and programming language. The model was used to assess economic and operational factors by generating scenarios and analyzing probable routine errors. In short, the results evidenced that initial value and operation speed are factors with the strongest impact on the costs of self-propelled sprayers and tractor-sprayer sets. Yet, the aerial application was mostly affected by fuel costs and crop row lengths. Moreover, the larger the spray tank volume, the lower the costs.

Resumo em Inglês:

ABSTRACT The objective of this study was to evaluate the effect of the seed conditioning process on the sanitary quality of Panicum maximum ‘Mombasa’ seeds. The seeds were sampled before processing and after exiting the seed blower and sieves (discharge from the top and bottom sieves), first gravity separator (intermediate discharge), seed treatment equipment (dyeing the seeds of the intermediate discharge from the first separator), and second gravity separator (upper, intermediate, and lower discharge). Sanitary analysis was performed by the Blotter Test method with and without surface disinfestation of the seeds, which were incubated at 20 ± 2 °C, with a photoperiod of 12 h, for 7 d. The conditioning process increased the incidence of Fusarium sp. in the Mombasa grass seeds. In addition, Cladosporium sp. and Alternaria sp. were found in and on the surface of the seeds and, therefore, can be disseminated by the seed conditioning machines. The percentage of seeds with Alternaria sp. decreased after dyeing and after the top discharge of the second gravity separator stage.

Resumo em Inglês:

ABSTRACT Laser sensor applications associated with LiDAR (Light Detection and Ranging) technology on platforms allow the evaluation of crop and forest biomass in a non-invasive way. This study presents the development of a measurement system based on LiDAR technology aimed at the proposed assessment of the height of sugarcane plants during the pre-harvest period. A laser sensor, a GNSS (Global Navigation Satellite System) receiver, and an inertial unit compose the measurement system. The equipment was integrated with a computer for data acquisition and installed on an agricultural tractor platform. The GNSS receiver with a real-time kinematic signal was synchronized to the laser sensor to obtain the point cloud and to the inertial unit to evaluate the intensity of the vibration from platform oscillation. Data acquisition was carried about 10 days before sugarcane harvest. The developed steps of acquisition and data processing enabled the generation of point clouds with a density of about 2,000 points m−2 and the extraction of metrics related to the height of sugarcane plants. The influence of vibration in the dataset was more significant in one of the experimental fields due the high-amplitude spectral power observed.

Resumo em Inglês:

ABSTRACT This article explores decision analysis regarding Drop and Hook (D&H) transportation operations at sugarcane mills. By means of a case study, a combination of a discrete event simulation model and multi-attribute utility theory was used to evaluate different configurations for sugarcane delivery systems using internal, external, or no D&H systems. A D&H strategy maximises truck utilisation, as semi-trailers can be handled independently of the traction unit of the trucks, which makes the transport system more agile. For internal D&H systems the semi-trailer detaching/attaching point is located inside the mill site while for external D&H systems it is located outside, before the trucks’ weighbridge. Each configuration requires different infrastructure which affects the supply of sugarcane for milling. The case study was applied to a sugarcane mill of a corporation located in São Paulo State. By means of discrete simulation, we determined that eighteen D&H configurations were feasible. By using the swing weighting multi-criteria decision analysis (MCDA) method, we identified fleet cost as the most important factor, while configurations with external D&H systems showed the best utility values. For this case study, the best configuration is to use the external D&H strategy with 28 road trains (truck and two semi-trailers), 12 additional semi-trailer sets, and 6 tractor units.

Resumo em Inglês:

ABSTRACT Fertilization systems that allow higher sowing speeds have been used in areas of grain production, as well as the use of intercropping to improve soil physical quality and provide better soil cover. This study aimed to evaluate soil attributes and the initial corn development and intercropping (corn + velvet bean, corn + pigeonpea, and corn + bonavist bean) as a function of fertilization systems (pre-sowing and sowing). The experiment was conducted in an Oxisol in a randomized block design in the 2 × 3 factorial scheme, with four replications. The number of days for emergence, plant stand, intercropping dry matter, soil straw cover, soil straw permanence index, penetration resistance, soil moisture, soil density, degree of compaction, and total soil porosity were measured. The percentage of soil straw cover was affected by fertilization system, mainly by pre-sowing fertilization. Soil physical attributes were not affected by fertilization and intercropping systems, except total porosity, in the 0–0.10 m layer, which has a combined effect of factors. The initial corn development was not affected by fertilization and intercropping systems. Velvet bean presented the highest number of days for the emergence and lower dry matter.