Revista Engenharia na Agricultura - Reveng

Numerical simulation applied to milk cooling

2020-09-13T23:31:50-03:00

A model is a representation of a real system that can be analysed and yield predictions under different operating conditions. The aim of this study was to model a milk cooling tank that cools milk to 4 °C to preserve its quality after milking at the farm. The model was developed and simulated using the software Ansys for finite element analysis. The results from the simulations were compared to experimental data. The model simulated milk cooling in the tank with an error lower than 2%, which is considered acceptable for numerical simulations. In other words, the model satisfactorily represents the real system. Thus, alternatives can be directly tested in the computational model to improve and optimise the milk cooling process and to better use the system without actually implementing them in the real system.

Quality of soy bean grain stored in bag silo

2020-12-10T15:16:25-03:00

Because of the rise in the use of bag silo in the last harvests due to the lack of static capacity in Brazil, the storage of grain in type of structure is currently seen as a solution to our storage deficit. Thus, the importance of maintaining the quality of grains for commercialization in these systems is considered. The objective of this experiment was to evaluate the quality of soybean grain stored in a silo bag, in the region of Dourados, State of Mato Grosso do Sul, Brazilian Central-West. The experiment was carried out in a cooperative, where soybean grain stored in silo bag are collected. The product had been received, processed at the end of the summer harvest and previously stored in metallic silos, and then transferred to the silo bags upon reception of the winter harvest. Thus, soybeans with an average water content of 11% w.b. were packed in bags composed of high-density polyethylene and hermetically sealed over a total period of 125 days, with collections of data on temperature and air relative humidity and grain sampling every 40 days. The collected samples were subjected to plant classification and analyses of water content, water activity, protein, lipids and color parameters were also performed. Na average rise of 5° C was observed in the temperature and 14% for air relative humidity which resulted in the of moldy and fermented grains after 125 days in the bags. The storage period factor was significant (p <0.05) in the variables of water content, color and oil. It was concluded that for soybeans the storage period in hermetic bags influences the quality of the grains and the internal environmental conditions in these structures are influenced by the convective microcurrents observed in the different positions inside the silo bag.

Mechanical properties of cowpea beans at different moisture contents

2021-04-19T14:08:07-03:00

Cowpea production has gained considerable ground in Brazil. Cowpea grain undergo different types of pressure and may crack and break during processing and storage, thus, there is a need to classify the mechanical properties of the beans. Therefore, this study aimed to evaluate the influence of the moisture content of cowpea beans on the maximum compressive force for fixed deformation and determine the proportional modulus of deformity under compression. The cowpea cultivars Novaera and Tumucumaque were evaluated at different moisture contents (0.12; 0.15; 0.18; 0.20; and 0.23 decimal d.b.). The experiment was arranged in completely randomized design for each moisture content and 10 deformation rates were applied (0.02; 0.04; 0.06; 0.08; 0.10; 0.12; 0.14; 0.16; 0.18; and 0.20 mm). The compression force was assessed using a universal testing machine and the proportional deformation modulus was determined. Following, hardness and elasticity of cowpea beans ??as a function of the moisture content were established. The compressive force required to deform cowpea beans decreases with increasing moisture content: between 2 and 105 N (Tumucumaque) and between 2 to 97 N (Novaera). The proportional deformation modulus of cowpea increased as the moisture content and deformation reduced, ranging from 4.9 x 107 to 31.9 x 107 Pa (Tumucumaque) and from 5.9 x 107 to 42 x 107 Pa (Novaera).

Performance of hydraulic ram built with different volumes of air chamber

2020-10-14T01:46:04-03:00

To capture surface water and groundwater, in most cases, electrical or fuel energy is required to drive a motor pump. This work aims to evaluate and compare the hydraulic characteristics of a hydraulic ram built with different volumes of PVC air chambers, according to its efficiency and economy. The study was developed at the Federal Rural University of the Amazon. Calibrated tanks and a stopwatch were used to obtain the supply flow, wasted water and repression volume. Four treatments were performed with 25% (125 L), 50% (250 L), 75% (375 L) and 100% (500 L) of raw material. For treatments with different volumes of air chambers, PVC tubes of 10, 20, 30, 40 and 50 cm in length were used. The experiment was a completely randomized design, carrying out the analysis of variance, Pearson correlation coefficient and the Tukey test for comparison among averages. There is a strong tendency to increase the repression volume and wasted when the volume of the air chamber is increased. The 0.250 L air chamber presented relevant results. In addition, it was demonstrated that with the increase in the volume of the air chamber, there was an increase in performance.

Can portable analyzers be reliable for biogas characterization?

2020-12-28T23:06:50-03:00

Anaerobic digestion for treatment of swine wastewater is an attractive alternative, among other aspects, for the generation of biogas. This gas is composed predominantly of methane and can be converted into electrical and thermal energy. However, the knowledge of the biogas composition is of paramount importance, especially regarding the methane content due to its energetic properties. The alternatives for this determination usually require high cost and specialized technicians. Therefore, the search for simple and low cost alternative solutions and techniques can improve the biogas use as an energy source and favor energy sustainability in pig farming. The present study aimed to compare the results of the methane composition of a portable analyzer with that of a Gasboard gas analyzer. The biogas was collected and characterized in a full cycle swine farm from January to December 2019 in the municipality of Teixeiras (MG), Brazil. The methane composition values did not differ statistically for a 5% significance level between the evaluated methods. The use of the portable kit is a simple and low cost alternative in determining the methane content in biogas and can be used reliably.

Water balance estimate of beans using a dynamic systems model based on crop coefficient (Kc) variation

2021-01-07T11:23:52-03:00

The crop coefficient (Kc) is one of the most important parameters for studying the water balance, which aims to assess the relationship between growth and production dynamics and the management of water resources in irrigation systems. Thus, in this study, the effect of Kc variation on the water balance was evaluated throughout the bean crop cycle in Northeast Brazil, using a dynamic systems model. The effect of Kc variation scenarios on the water balance in the bean crop in Northeastern Brazil was simulated using the Vensim program. The soil water storage was used as state variable, input flow variable and outflow of water in the soil, and auxiliary variables that influence system flows were also considered. Thus, four simulation scenarios were performed changing values of the bean crop coefficient (Kc = 0.62; Kc = 0.72; Kc = 0.82; Kc = 0.92). The variation in soil water storage showed negative values in most phenological phases, showing significant differences between Kc conditions, depending mainly on the precipitation dynamics.

Phytoextraction and nutritional quality of forages cultivated in a constructed wetland system for wastewater treatment

2021-05-04T18:15:53-03:00

This study aimed to evaluate the effects of different concentrations of sodium on the phytoextraction of nutrients and nutritional quality of forages (P. purpureum Schum and C. dactylon Pers) grown in wetland system constructed for wastewater generated in cattle slaughterhouses (WGCS) treatment. The experiment was conducted in a randomized complete block design with three replications. The treatments were tested using 2 x 5 factorial scheme, as follows: two species of grass (P. purpureum Schum and C. dactylon Pers) and five concentrations of sodium in WGCS: 70, 100, 150, 200 and 250 mg L-1. The phytoextraction potential of nutrients and the nutritional quality of forages grown in pots simulating a wetland system constructed for WGCS with sodium concentrations were assessed in terms of the contents of the nutrients nitrogen, phosphorus, potassium, calcium, magnesium and sodium in leaf tissues. The accumulations of these nutrients in the produced forages were also evaluated. Both species presented different behaviors regarding their nutrient phytoextraction potentials. The nutritional quality was changed in the forages due to the cultivation in constructed wetlands. Forage C. dactylon Pers presented higher phytoextraction potential of sodium and potassium and P. purpureum Schum presented a higher nutritional quality.

Soybean yield in succession to single and intercropping corn and brachiaria and submitted to differents irrigation intervals

2021-01-20T08:01:14-03:00

The experiment was performed at a non-acclimatized protected screened environment. The objective of the study was to evaluate the influence predecessor crops of single and intercropping corn and brachiaria on soybean yield submitted to irrigation intervals. The experimental design adopted was in a split split-plot randomized block design with four repetitions. Two soil classes (dystroferric Red Latosol and dystrophic Red Latosol) were evaluated in the plots, three intervals between irrigations were used during the soybean flowering (each one day, two days and three days) in the subplots and three types straw in the crops autumn-winter (single corn, single brachiaria, intercropping corn and brachiaria) in the sub-subplots. The two soybean plants cultivated in polyethylene pots containing 20 liters of dystroferric Red Latosol or dystrophic Red Latosol corresponded to each repetition, according to the treatment. The irrigation intervals of three and two days, in dystroferric Red Latosol and dystrophic Red Latosol, respectively, with single brachiaria at the previous crop provided greater number and weight of pods, higher number of grains and higher soybean yield. Irrigation every three days with single corn at the previous crop in dystroferric Red Latosol and dystrophic Red Latosol, resulted in the lower soybean performance.

Evaluation of the performance of covered lagoon digester in terms of the solids loading

2020-12-18T19:17:27-03:00

The use of anaerobic digesters to convert residual biomass for energy use and nutrient recovery has been increasingly indicated by the operational simplicity and added value of the treatment by-products. However, the levels of solids present in the influents to be treated directly influence the operation and management of the system. Thus, the objective of the study was to evaluate the performance of covered lagoon digesters in terms of the solids loading in the swine wastewater treatment system. The study was performed in a farm located in Zona da Mata Mineira. The monitoring took place from September 2018 to August 2019. The influent flow of waste was estimated based on the analysis of monthly water consumption on the farm. The collection and sampling took place weekly, the influents and effuents were analyzed in terms of the solids loading of total solids (TS) and volatiles solids (VS). The mean total flow distributed to the two digesters was 102.3 m³.d-1, with a mean hydraulic retention time (HRT) of 24.5 days. The results ranged from 1.14 to 2.83% for TS at the start of treatment. In most of the monitored months, anaerobic digesters were being fed with organic overload in terms of VS, which consequently affected the efficiency of the system, which were 33.6% for TS and 39.5% for VS.

Assessment of water availability in the period of 100 years at the head of the São Francisco river basin, based on climate change scenarios

2021-04-13T09:13:31-03:00

In the last century, changes in climate trends have been observed around the planet, which have resulted in alterations in the hydrological cycle. Studies that take into account the impact of climate change on water availability are of great importance, especially in Brazil’s case, where water from rivers, beyond being destined for human consumption, animal watering and economic activities, has a great participation in electricity generation. This fact makes its energy matrix vulnerable to variations in the climate system. In this study, a flow analysis for the head of the São Francisco river basin was performed between 2010 and 2100, considering the precipitation data of the CCSM4 climate model presented in the Fifth Assessment Report (AR5) from the Intergovernmental Panel on Climate Change (IPCC). Projections of future flow were performed for the scenarios RCP4.5 and RCP8.5, based on the SMAP rain-flow model, followed by a comparative analysis with the present climate. In general, we can observe that the decades of 2010 to 2100 will be marked by the high levels of precipitation, interspersed by long droughts, in which the recorded flow will be lower than the Long Term Average (LTA) calculated for the basin. Therefore, new management strategies must be considered to maintain the multiple uses of the basin.

Modeling of technical, economic, environmental and ergonomic parameters of forestry machines in function of the quantity of days of the working scale

2021-02-18T10:02:28-03:00

Forest machine operators work on a long scale of work, which causes physical and psychological wear and consequently reduced productivity and increased fuel consumption. The objective of this research was to verify the influence of the number of days of the work schedule of harvester and forwarder operators in low-volume forest on technical, economic, environmental and ergonomic parameters. The research was performed in forest stands with an average wood volume of 0.10 m³ tree-1. In the first, second, third and fourth day of the work schedule, productivity, energy demand, production cost, carbon dioxide emission and the occurrence of fatigue in the operators were determined. The productivity values ??of harvester operators on the third and fourth days of the work schedule decreased by 2.62 and 7.74%, respectively, in relation to the average value of the first and second days. The productivity of forwarder operators was similar in the first three days of the work schedule, with a more marked reduction in the fourth day. The reduction in the number of days in the forest machine operators’ work schedule makes the operation more sustainable from a technical, economic, environmental and ergonomic point of view.

Performance of an agricultural engine using turbocharger and intercooler

2021-04-19T15:21:07-03:00

This paper aimed to evaluate the effects of air and fuel supercharging in an agricultural engine. The analyzed variables consisted of torque, power, and specific fuel consumption. Tests were carried out using a dynamometer through the power take-off of an agricultural tractor. The experiment was carried out at a laboratory in a completely randomized design arranged under a two-factorial scheme, with three replications. Six engine configurations (natural aspiration, natural aspiration + service, turbocharger, turbocharger + service, turbocharger + intercooler, and turbocharger + service + intercooler) and 10 engine speeds (1,200, 1,300, 1,400, 1,500, 1,600, 1,700, 1,800, 1,900, 2,000, and 2,100 rpm) were evaluated. The turbocharger alone did not increase engine torque and power. The increase in fuel flow enhanced engine performance for the evaluated configurations. Turbocharger + service and turbocharger + service + intercooler configurations reduced specific fuel consumption by up to 10% and increased torque and power by approximately 30% compared to the original configuration (natural aspiration).

Can Digger Blades Wear Affect the Quality of Peanut Digging?

2021-02-19T11:12:59-03:00

Brazilian peanut harvests have been fully mechanized and are divided into two operations, namely digging and gathering. In both operations, losses are observed, and it is essential to avoid losses to maintain adequate machine maintenance. In this study, we aimed to quantify the interference of the harvesting period (morning, afternoon, and night) and wear of the digger-inverter mechanism (blades) on the loss indexes during the dig operation. The experiment was conducted in a commercial field using worn and new blades to dig peanuts at three different periods of the day. Losses were quantified by measuring data at 20 points, which were separated by 20 m for each treatment. The shift work did not interfere with peanut losses. However, the blade condition exhibited a strong influence on increasing the losses. Peanut growers can increase profits by up to 22% by reducing digging losses solely by periodically changing blades.

Physiological quality of mechanically harvested chickpea seeds

2021-01-08T11:20:04-03:00

Our objective was to evaluate the occurrence of mechanical damage in chickpea seeds with the combination of two harvester speeds (2.5 and 3.5 km.h-1) and three adjustments for rotor rotation speeds (500, 700, and 850 rpm). Harvesting was carried out in a seed production field. Seeds were evaluated for purity, germination (G), first count (FC), germination speed index (GSI), hypochlorite, electrical conductivity, and tetrazolium tests. There was an effect of harvester speeds on seed physiological quality for the first count (FC), germination (G), germination speed index (GSI), especially when combining with high rotor rotation speed. In these cases, the speed of 2.5 km.h-1 resulted in lower values. This harvester speed also had worse results when combining with 850 rpm for purity and hypochlorite tests. The tetrazolium test was not efficient in identifying differences in seed quality. There was no significant interaction between harvester speeds and rotor rotation speeds for the conductivity test. Evaluating the harvester speed’s isolated effect (3.5 km.h-1), we identified problems in seed vigor due to the higher value of exudates in the electrical conductivity test. Low harvester speed (2.5 km.h-1) associated with high rotor rotation speeds (700 and 850 rpm) causes a reduction of the physical and physiological quality of seeds.