Search

The principal objective of agriculture is the production of a high yield of healthy crops. This yield may be improved by the automatic detection of diseases and the consequent reduction in the use of pesticides. A digital processing system for images was thus developed and used to identify lesions on the leaves of cotton plants. A collection of 60,659 images of sub-metric resolution showing samples of soil and both healthy and damaged leaves was obtained and processed with an algorithm for the extraction of texture from 102x102-pixel samples. Then they analyzed with a neuro-fuzzy classifier trained to discriminate the three types of regions (soil, healthy leaf, and lesioned leaf). The algorithm developed was able to recognize the three classes. It generated a great amount of information on recognition of background which was more consistent than leaf damage areas. Therefore, it surpassed the performance of areas of healthy leaves. A similar trend was found for sensitivity. The overall accuracy of the system was 71.2%, suggesting that the unbalanced data of the different classes had skewed the results of the algorithm, as the number of false positives for the less well represented classes was greater. The analysis of unbalance (F-Score) showed that, independent of the volume of data, the attributes of texture utilized yielded better results for the images containing areas of damage in relation to overall accuracy. Therefore, given the challenges involved in the automatic identification of lesions in agricultural crops, such as variations in illumination, color, and texture, as well as obstruction, overlapping, and complexity of the region of which the image was taken, the behavior of the model was deemed satisfactory. Given the hybrid nature of the model, it should contribute to the state of the art in the use of intelligent systems in agriculture. This algorithm is available at https://github.com/rafaeufg/Cotton-diseases

Chlorophyll content is a widely used parameter for nutritional status diagnosis in sugarcane. This study aimed to develop a predictive model of chlorophyll content in sugarcane seedlings using spectral imagery analysis within the electromagnetic spectrum visible range. The experiment was carried out in a split-plot design, with two fertilization rates and three sugarcane cultivars. For chlorophyll analysis, 144 leaves were collected from seedlings. Chlorophyll contents were extracted and measured by SPAD-502 meter. Spectral images within the range of 480 to 710 nm were analyzed using reflectance, absorbance (white source), and fluorescence (source at 405 and 470 nm) responses. Predictive models were developed using multivariate regression methods such as Principal Component Regression and Partial Least Squares Regression. We chose the best model through absorbance response using variable selection and the PLSR method (R2P = 0.718 and RMSEP = 7.665). The wavelengths of 480, 490, 500, 600, 630, and 640 nm were identified as the best for total chlorophyll content determination. The spectral image processing-based method can provide a chlorophyll measurement equivalent to SPAD, with the advantage of having a higher spatial coverage over the entire leaf area. Besides, it can also support automation of the chlorophyll measurement in greenhouses.

Background The San Francisco Valley region from Brazil is known worldwide for its fruit production and exportation, especially grapes and wines. The grapes have high quality not only due to the excellent morphological characteristics, but also to the pleasant taste of their fruits. Such features are obtained because of the climatic conditions present in the region. In addition to the favorable climate for grape cultivation, harvesting at the right time interferes with fruit properties. Results This work aims to define grape maturation stage of Syrah and Cabernet Sauvignon cultivars with the aid of deep-learning models. The idea of working with these algorithms came from the fact that the techniques commonly used to find the ideal harvesting point are invasive, expensive, and take a long time to get their results. In this work, convolutional neural networks were used in an image classification system, in which grape images were acquired, preprocessed, and classified based on their maturation stage. Images were acquired with varying illuminants that were considered as parameters of the classification models, as well as the different post-harvesting weeks. The best models achieved maturation classification accuracy of 93.41% and 72.66% for Syrah and Cabernet Sauvignon respectively. Conclusions It was possible to correctly classify wine grapes using computational intelligent algorithms with high accuracy, regarding the harvesting time, corroborating chemometric results. © 2020 Society of Chemical Industry.

Weeds interfere in agricultural production, causing a reduction in crop yields and quality. The identification of weed species and the level of infestation is very important for the definition of appropriate management strategies. This is especially true for sugarcane, which is widely produced around the world. The present study has sought to develop and evaluate the performance of the Bag-of-Features (BoF) approach for use as a tool to aid decision-making in weed management in sugarcane production. The support vector machine to build a mathematical model of rank consisted of 30553 25x25-pixel images. Statistical analysis demonstrated the efficacy of the proposed method in the identification and classification of crops and weeds, with an accuracy of 71.6% and a Kappa index of 0.43. Moreover, even under conditions of high weed density and large numbers of overlapping and/or occluded leaves, weeds could be distinguished from crops This study clearly shows that the system can provide important subsidies for the formulation of strategies for weed management, especially in sugarcane, for which the timing of weed control is crucial.

This work presents a remote sensing solution for sugarcane precision agriculture based on a drone-borne differential interferometric synthetic aperture radar (DlnSAR) operating in the P-, L-, and C-bands. With one flight pass, the system can estimate the soil moisture, the plantation height, and the above-ground biomass map; and predict the harvest date and the respective productivity. With two flight passes, it assesses the crop growth via differential interferometry. A new methodology dedicated to sugarcane plantation was developed based on the existing methodologies for soil moisture and biomass measurement. The image information from the three bands, plus the C-band InSAR and P-band DInSAR information, show immense potential for efficient and low-cost monitoring. The results validated the methodology in a large sugarcane mill.

This paper presents a high-accuracy single-pass drone-borne Interferometric Synthetic Aperture Radar System in the P-band (P-InSAR) for forest inventory, where ground and canopy heights are accurately determined. Full penetration is proven for a eucalyptus forest with a tree spacing of 2.5 m by 3.0 m, and the measured digital terrain accuracy is compared with well-known statistical models. Combining a C-band single-pass InSAR with P-InSAR, forest height is estimated with 5 % accuracy for forest inventory. Both surface and digital ground models are presented and compared with ground truth measurements.

Accurate, high-resolution maps of for crop growth monitoring are strongly needed by precision agriculture. The information source for such maps has been supplied by satellite-borne radars and optical sensors, and airborne and drone-borne optical sensors. This article presents a novel methodology for obtaining growth deficit maps with an accuracy down to 5 cm and a spatial resolution of 1 m, using differential synthetic aperture radar interferometry (DInSAR). Results are presented with measurements of a drone-borne DInSAR operating in three bands—P, L and C. The decorrelation time of L-band for coffee, sugar cane and corn, and the feasibility for growth deficit maps generation are discussed. A model is presented for evaluating the growth deficit of a corn crop in L-band, starting with 50 cm height. This work shows that the drone-borne DInSAR has potential as a complementary tool for precision agriculture.

The use of deep learning models to identify lesions on cotton leaves on the basis of images of the crop in the field is proposed in this article. Cultivated in most of the world, cotton is one of the economically most important agricultural crops. Its cultivation in tropical regions has made it the target of a wide spectrum of agricultural pests and diseases, and efficient solutions are required. Moreover, the symptoms of the main pests and diseases cannot be differentiated in the initial stages, and the correct identification of a lesion can be difficult for the producer. To help resolve the problem, the present research provides a solution based on deep learning in the screening of cotton leaves which makes it possible to monitor the health of the cotton crop and make better decisions for its management. With the learning models GoogleNet and Resnet50 using convolutional neural networks, a precision of 86.6% and 89.2%, respectively, was obtained. Compared with traditional approaches for the processing of images such as support vector machines (SVM), Closest k-neighbors (KNN), artificial neural networks (ANN) and neuro-fuzzy (NFC), the convolutional neural networks proved to be up to 25% more precise, suggesting that this method can contribute to a more rapid and reliable inspection of the plants growing in the field.

Synthetic Aperture Radar (SAR) has become a powerful remote sensing tool during the last 25 years. Most relevant products are three dimensional and projected on a cartographic system: topographic, thematic and change-detection maps. Starting with the requirements of precision agriculture, subsurface tomography, subsidence and cartography a low weight drone-borne SAR was designed. It operates in P, L and C-bands with cross-track (InSAR) and differential Interferometry (DInSAR). The requirements of the foreseen applications, concept, design, results and validation from regular surveys and ground truths are presented.

The challenges of modern agriculture have led to the development of localized management tools which allow the rationalization of the use and application of pesticides, a reduction in production costs and the optimization of agricultural processes. This study was carried out to develop an algorithm capable of orienting weed control in the management of a corn crop, using digital image analysis to identify the level of weed infestation in the field. The seeds of six species of weed were sown in an experimental plot of corn, and daily images were captured for 40 days for the evaluation of the level of weed infestation (low, intermediate or high). The algorithm developed was able to target information about the plants and soil accurately and discriminate the residual information as referring to either the culture or weeds. The proposed algorithm has achieved 90% accuracy in identifying the level of infestation from images already evaluated by experts. The results can thus be used as part of weed control strategy, with the incorporation of the geographic coordinates of the image making possible the construction of a map of the level of weed infestation in the different areas where the crop is growing.

Differential synthetic aperture radar interferometry (DInSAR) has been widely applied since the pioneering space-borne experiment in 1989, and subsequently with the launch of the ERS-1 program in 1992. The DInSAR technique is well assessed in the case of space-borne SAR data, whereas in the case of data acquired from aerial platforms, such as airplanes, helicopters, and drones, the effective application of this technique is still a challenging task, mainly due to the limited accuracy of the information provided by the navigation systems mounted onboard the platforms. The first airborne DInSAR results for measuring ground displacement appeared in 2003 using L- and X-bands. DInSAR displacement results with long correlation time in P-band were published in 2011. This letter presents a SAR system and, to the best of our knowledge, the first accuracy assessment of the DInSAR technique using a drone-borne SAR in L-band. A deformation map is shown, and the accuracy and resolution of the methodology are presented and discussed. In particular, we have obtained an accuracy better than 1 cm for the measurement of the observed ground displacement. It is in the same order as that achieved with space-borne systems in C- and X-bands and the airborne systems in X-band. However, compared to these systems, we use here a much longer wavelength. Moreover, compared to the satellite experiments available in the literature and aimed at assessing the accuracy of the DInSAR technique, we use only two flight tracks with low time decorrelation effects and not a big data stack, which helps in reducing the atmospheric effects.

The partial dehydration of grapes after harvest aimed at winemaking has been shown to be a process that brings increased concentration of sugar and phenolic compounds in the must, which affects the quality of the wines produced. However, the works developed so far have studied the process for temperatures up to a maximum of 25°C and air velocity lower than 1 m.s-1. This study aimed to analyze the physical-chemical changes concentration of total soluble solids (TSS) and phenolic compounds (PC) after partial dehydration of 'Syrah' grapes subjected to two treatments combining two temperatures and one air velocity (T1= 22.9°C/1.79 m.s-1 and T2 = 37.1°C/1.79 m.s-1) and relative humidity of 40%. The water loss of the grapes was approximately 14% and the drying process lasted between 34 and 68 h for treatments T2 and T1, respectively. We experimentally and statistically verified that the treatments promoted significant increase in TSS and PC; however, for PC at the temperature of 37.1°C, the increase accounted for approximately 27%, whereas, for the temperature of 22.9°C, it was only 12%. For TSS, the increase was on average 12.47±0.9% between both treatments. The results demonstrate that it is possible to moderately dry grapes, which consequently results in improvements in their chemical composition and can improve the quality of wine. Key words: Wine, polyphenols, soluble solids, drying, instrumentation.

The partial dehydration of grapes after harvest and aimed wine-making, has been shown to be a process that brings increased concentration of sugar and phenolic compounds in the must, which results in the quality of the wines produced. However, the works developed so far studied the process for temperatures up to a maximum of 25°C and air velocity less than 1 m.s-1. This study aimed to analyze the physical and chemical changes (concentration of total soluble solids (TSS) and phenolic compounds (CPC)) after partial dehydration of 'Niagara Rosada' grapes at the temperature subjected to two treatments combining two temperatures and one air velocity (T1= 22.9°C/1.79 m.s-1 and T2 = 37.1°C/1.79 m.s-1), and relative humidity of approximately 40%. The loss of water in the grapes was approximately 14% and the drying process lasted between 20 to 50 h for the treatments T1 and T2, respectively. We experimentally and statistically verified that the treatments promoted significant increase in TSS and CPC; however, for CPC at the temperature of 37.1°C, the increase accounted for approximately 29%, whereas, for the temperature of 22.9°C, it was only 5%. For TSS, the increase was on average 14.4 ± 3.9% between both treatments. Key words: Chaptalization, temperature, air velocity, winemaking.

A potência de sinal é um importante parâmetro a ser considerado em um projeto de implantação de rede de sensores sem fio no meio agrícola. Este trabalho tem como objetivo coletar dados de qualidade de sinal transmitido entre uma estação base e um nó sensor situado no interior de uma casa de vegetação, localizada no campo experimental da Faculdade de Engenharia Agrícola - UNICAMP, com o auxílio de ferramentas computacionais. Após a implantação do nó sensor foram realizados experimentos com vista a se verificar alcance e qualidade do sinal de acordo com sua potência. Através desses ensaios foi possível concluir que uma potência de sinal com valor de -12,2 dBm é suficiente para manter a transmissão entre a estação base e nó sensor. Testes também foram realizados com uma potência de sinal de -9,2 dBm e mostraram que a rede possuía qualidade classificada "muito alta" porém, através do teste de duração da bateria, nota-se que existe economia de energia ao se utilizar a potência de sinal de -12,2 dBm. Foi avaliada a influência que o valor da potência de sinal tem sobre a qualidade do sinal de transmissão e recepção, o gasto de bateria e o alcance do sinal. The signal strength is an important parameter to be considered in a project to establish network of wireless sensors in an agricultural environment. This work aims to collect quality data signals transmitted between a base station and a sensor node located inside a greenhouse, which is an experimental field located in the College of Agricultural Engineering - UNICAMP, with the help of computational tools. After sensor node deployment, experiments were performed in order to check range and signal quality. Through these experiments, it was concluded that a radiofrequency power value of -12.2 dBm is sufficient to maintain transmissions between base station and the sensor. Tests were also performed to a radiofrequency power of -9.2 dBm, and showed that the network had quality rated as "very high". However, by testing the battery life, it is noted that there is an energy saving when the radiofrequency power of -12.2 dBm is used. It was shown that the value of the signal strength has an influence on the quality of signal transmission and reception, battery depletion and signal range.

The spectral images used as an alternative to the quality nondestructive evaluation, can contribute to improve monitoring and control of variables involved in partial dehydrated grapes for production of juice and / or wine, with the product quality as goal. This study aimed to differentiate Benitaka variety grapes with different concentrations of soluble solids using spectral image of fluorescence. The grape samples come from to Vale do Sao Francisco-State of Bahia, and were forwarded to the Laboratory of Atomic Interactions-Institute of Physics of Sao Carlos, University of Sao Paulo. The treatments consisted by two (T1 and T2) being T1-fresh grapes (12.54 +/- 0.09 °Brix), and T2-partial dehydrated grapes (in forced air oven at T=65°C and RH=50%) (13.32 +/- 0.08°Brix). The fluorescence image system used consists in a scientific CCD camera, lens system, a variable optical filter, and illumination system with LEDs (UV-405 nm). The wavelengths spectrum used in this study were between 480 to 750 nm. The spectral calibration occurred through a principal component analysis (PCA) in Matlab, wherein principal components which represent most the data were selected, separating T1 e T2. To select the best wavelength was applied a linear regression forward a PCA model to image data. After the PCA implementation was possible to distinguish the different soluble solids values in grapes to T1 and T2, setting the best wavelengths were to 480; 493; 552; 568; 605; 645; 666; 690 and 715 nm. The applied technique can contribute to technological advancement in the non-destructive evaluation field and real-time in high added value products such as derivatives Viticulture.

Fruit and vegetable production has been growing significantly every year, in Brazil and worldwide. Therefore, the application of appropriate technologies requires constant improvement and technological investment, from harvest to commercialization. Particularly, packages are a significant part of post-harvest losses statistics for fresh fruit and vegetables; only 10 to 50% from the total yield are reported per year, depending on the country’s development, climate, cold chain employment, logistical aspects, and others. This study introduces the methodology of a packaging design project and discusses results of its application for design and optimization of mango (Mangifera indica L., ‘Tommy Atkins’) and banana (Musa cavendishii ‘Nanica’) packages, based on computer simulation and experimental validation. It was aimed to minimize material volume (reforestation wood - Pinnus ellioiti) by combining structural, thermal, ergonomic and geometric aspects, as effective areas and opening distribution. The Finite Element Method (FEM) was employed for optimization and structural dimensioning, allowing a material volume reduction of 83% for banana package and 67% for mango package. Due to the effective opening area distribution, the cooling time reduction of fruit, which were cooled by forced-air, was on average 50% as for packaging commercially utilized. The results of this study, as well as the methodology applied, may be employed for commercial purposes, such as for reforestation wood packages, provided these are watertight and non-reutilized, even for export markets. The methodology used combined computer and engineering tools, at an appropriate cost-benefit relationship among structural, geometric, thermal and ergonomic aspects.

A aplicação de técnicas de automação e controle em casas de vegetação teve início nos anos 50, com o controle da temperatura através de termostatos; desde então, as mudanças tecnológicas têm abarcado todos os aspectos que compõem o sistema, do projeto estrutural até aspectos relacionados à sustentabilidade. Dentre os parâmetros que devem ser controlados, a temperatura e umidade relativa do ar, a radiação solar, a concentração de CO2, a ventilação e a fertigação têm tido uma evolução significativa, dos quais se apresenta uma panorâmica através da revisão do estado da arte de trabalhos publicados nessas temáticas, nos últimos anos. Na atualidade, temas relacionados com a redução do impacto ao meio ambiente e a produção eficiente e com qualidade, estão levando as casas de vegetação ao caminho da Agricultura de Precisão.

RESUMO Descreve-se o software TERMICONT para a supervisao e controle de uma planta de secagem, monitorando a temperatura e umidade do ar, velocidade de rotacao do motor do ventilador e consumo de energia. A planta foi instrumentada com sensores de temperatura, umidade relativa e potencia ativa. O aplicativo foi desenvolvido em LabView 7.11, com interface homem-maquina de facil visualizacao, configuracao do tipo de controle, obtencao das curvas do sistema (malha aberta e fechada), para a modelagem matematica e estudo das estrategias de controle. O aplicativo podera ser usado como ferramenta de atuacao local e remota (Web Lab), controlando a vazao de ar e potencia da resistencia de aquecimento, aquisicao e armazenamento dos dados do processo. A planta sera disponibilizada para a realizacao de pesquisas em instrumentacao e controle de processos e servira de ferramenta didatica para o desenvolvimento de aulas praticas no curso de Engenharia Agricola. Palavras-chaves: Instrumentacao, Temperatura, Umidade, Vazao de Ar, Rotacao, Consumo de Energia.

The grapes dehydration to make wine, in controlled environment and with variance in temperature and humidity, began to be studied with greater emphasis recently for some grape varieties, due to the proven effects on the higher concentration of phenolic compounds and the positive change in aroma. This chapter focuses on process control in with particular emphasis in instrumentation, applied technologies and main quality results.

Este trabalho teve como objetivo desenvolver um estudo teórico através do modelo matemático de Fourier, em sua forma unidimensional e em coordenadas esféricas, o que é descrito por uma equação diferencial parcial linear de segunda ordem, para a obtenção das curvas e do tempo de resfriamento de frutas esféricas. Utilizou-se o Método das Diferenças Finitas (MDF) segundo o esquema implícito no ambiente computacional Matlab 6.1, analisando-se e comparando os principais resultados através do método de ajuste spline. O modelo matemático foi validado com dados experimentais do resfriamento de laranja Valência num sistema com ar forçado (Q = 1933 m³ h-1, e velocidade em torno de 1 m s-1), com temperatura inicial de 26,57 ºC e resfriada até 1 ºC. Os resultados teóricos obtidos com a simulação foram comparados com os encontrados com a aplicação de um modelo bidimensional desenvolvido em coordenadas esferoidais prolato, com o emprego do Método dos Volumes Finitos (MVF) implementado em Fortran 77. Os dois modelos e métodos aplicados mostram-se aptos para caracterizar o processo de resfriamento das frutas, principalmente em termos de valores práticos específicos, uma vez que geraram resíduos desprezíveis. Apesar destes resultados, o valor do coeficiente convectivo de transferência de calor foi significativamente diferente; tal variação mostra como este coeficiente é sensível a vários fatores do processo de resfriamento e, ainda, que se deve aprofundar as pesquisas para a determinação efetiva do valor do mesmo.The objective of this research was to conduct a study using the Fourier one-dimensional mathematical model, in spherical coordinates, which is described as a second order linear partial differential equation, in order to know the curves and the cooling time of spherical fruits. The implicit Finite Differences Method (FDM) implemented in the computational environment Matlab 6.1 was used, analysing and comparing the main results by the spline method. The validation of the mathematical model was carried out using experimental data of Valencia oranges inside a system with forced air (Q = 1933 m³ h-1 and air velocity around 1 m s-1), at the initial temperature of 26.57 ºC and cooled till 1 ºC. The theoretical results obtained in this way were compared with those obtained from the use of a two dimensional mathematical model, in spheroid prolato coordinates, using the Finite Volume Method (FVM) implemented in Fortran 77 code. Both of these model and methods were able to characterize the cooling process, mainly in terms of the practical specific values, once the residues can be disregarded. Although, the value of the convective heat transfer coefficient was significantly different; this variation shows how this coefficient is sensible to the assumptions of the cooling process and that this research must continue in order to determine its effective value.

Este trabalho apresenta um estudo para comparar o resfriamento rápido de laranja Valência (Citrus sinensis O.), com ar forçado e com água gelada. O sistema de resfriamento rápido com ar forçado operou com um fluxo de ar de 1.933m³/h (3 l/s por kg de produto resfriado), a uma temperatura de 1ºC e UR=88,4 ± 2,0%, com uma velocidade do ar em torno de 1m/s. Nos experimentos com água gelada foi utilizado um sistema de imersão, com uma capacidade de 0,23m³ de água a uma temperatura de aproximadamente 1ºC. Foi determinando o tempo meio e de sete oitavos do resfriamento, partindo das leituras de temperatura, perfazendo-se duas repetições em cada experimento. Os resultados mostraram que, o resfriamento do leito de frutas com ar forçado não é homogêneo, obtendo-se um tempo de sete oitavos do resfriamento que variaram de 107min a 170min, dependendo da posição do fruto no interior da embalagem. Já no sistema com água gelada, o resfriamento acontece uniformemente em todo em todo o leito de frutos, sendo o tempo médio de resfriamento de 57min.This work presents a study to compare the orange Valência (Citrus sinensis O.) cooling with forced-air cooling and hydrocooling. The forced-air cooling system operated with air flow of 1933m³/h, at 1ºC, RH= 88,4 ± 2,0% and air velocity around 1m/s. The experiments with immersion hydrocooling systems with capacity of 0,23m³ of water at 1ºC, approximately. The half-cooling time and seven-eighths cooling time, they are determinate with the temperature data, made two repetitions. The results showed that the cooling the bed fruits, with air cooling, is not homogeneous, and obtained cooling time average, between 107min and 170min, depending on the position the fruit in the package. In the hydrocooling system, the cooling of the bed fruits happens uniformly in the bed, with average cooling time of 57min.

Este trabalho apresenta as curvas de resfriamento de banana-prata (Musa balbisiana Colla) e os valores do tempo de meio e sete oitavos de resfriamento, partindo do cálculo da Taxa Adimensional de Temperatura. Os frutos foram resfriados num sistema com ar forçado a 7ºC, umidade relativa de 87,6±3,8%, e velocidade do ar entre 1 e 0,2 m/s. Aplicou-se um delineamento experimental inteiramente casualizado, usando um esquema fatorial 2x2 (dois fluxos de ar (fatores) e duas embalagens (níveis)), para um nível de significância de 10%. Os fluxos de ar foram 1.933 a 1.160 m³/h, e as embalagens se diferenciaram pela porcentagem de área de abertura disponível para a ventilação (40 e 3,2%). Foi constatada uma diferença significativa no tempo de resfriamento, tanto quando aplicadas as duas taxas de ar como quando usadas as duas embalagens. O menor tempo de resfriamento foi atingido no tratamento que combinou a maior taxa de ar (1.933 m³/h) com a embalagem de maior área de aberturas (40%). O maior tempo de resfriamento foi atingido no tratamento que combinou a menor taxa de ar (1160 m³/h) com a embalagem de 3,2% de área efetiva de abertura. Os resultados obtidos demonstram que o tempo de resfriamento depende, em grande medida, da taxa de ar e do tipo de embalagem usada. O tempo de resfriamento variou em média entre 117 a 555 min, dependendo do tratamento aplicado. Não se constatou diferença significativa nas perdas de massa entre os diferentes tratamentos. This work presents the cooling curves for bananas Prata, (Musa balbisiana Colla), and determinates half-cooling and seven-eight cooling times and the cooling rate. Bananas were kept in a cold room with a forced-air system at 7ºC and RH = 87.6±3.8%. The experiment was conducted in a 2x2 factorial design, to test the effects of two flow rates (factors) of air passing through the product, and two types of boxes (levels). The statistical analysis was performed at p

The sugarcane is one of the most important crops in Brazil, the world´s largest sugar producer and the second largest ethanol producer. The presence of weeds in the sugarcane plantation can cause losses up to 90% of the production, caused by the competition for light, water and nutrients, between the crop and the weeds. Usually sugarcane plantations occupy large fields, and due to this, the weeds control is mostly chemical, which is more practical and cheaper than mechanical control. In the chemical control, the dosage and type of herbicides has been calculated by sampling, which causes problems of waste and misapplication of herbicides, since the degree of infestation may be variant from one location to another, as well as the species presents in the plantation. In order to avoid unnecessary waste in the herbicides application, there are some studies about weed identification using images taken from satellites, solution that have proved to have the advantage of covering the whole plantation, solving the problems of sample surveying, nevertheless, this method its dependent of a high weed density to ensure a good pattern recognition and its affected by the influence of clouds in the imagery quality. This work proposes a system for weed identification based on pattern recognition in imagery taken from a Remotely Piloted Aircraft (RPA). The RPA is able to fly at low altitude, so it is possible to take images closer to the plants and make the weed identification even in low infestation levels. In an initial evaluation, the system reached an overall accuracy of 83.1% and kappa coefficient of 0.775, using k-Nearest Neighbors (kNN) classifier.

Agriculture plays a major role in the Brazilian economy so that actions such as reducing costs and improving the productive system are sought continuously. In the cultivation of sugarcane, the control of weeds is among the factors that increase the cost of production, since the weeds compete with the crop for water, nutrients and sunlight, and can compromise harvesting procedures. An automated system capable of distinguishing weed culture is a potential tool in the search for a more economical and sustainable agriculture. Such a system can be associated to equipment for spraying, or even for mapping the field infestation. In this paper, we propose a new approach for automatic classification of weeds and crop digital images. The aim is to assess whether a method based on the visual bag of words can properly discriminate six weeds and sugarcane, rate the classification and the time suitable for implementing real-time operations. In our experiments, we took into account only one descriptor for describing characteristics of the concerned plants. Analyses the results show that the method achieved 94 % hit rate, using a validation set of 149 test images. The processing time for each image is about 34 seconds, indicating the need the adjustment for consider its use in real-time operations. Nevertheless, the method proposed here constitutes an interesting alternative to the construction of functional maps of infestation which, eventually, can be considered in localized agricultural treatment.

This study aimed to verify the influence of partial dehydration of "Niagara Rosada" grape clusters in physicochemical quality of the pre- fermentation must. In Brazil, during the winemaking process it is common to need to adjust the grape must when the physicochemical characteristics of the raw material are insufficient to produce wines in accordance with the Brazilian legislation for classification of beverages, which establishes the minimum alcohol content of 8.6 % for the beverage to be considered wine. Therefore, given that the reduction in the water content of grape berries allows the concentration of chemical compounds present in its composition, especially the concentration of total soluble solids, we proceeded with the treatments that were formed by the combination of two temperatures (T1-37.1ºC and T2-22.9 ºC) two air speeds (S1: 1.79 m s-1 and S2: 3.21 m s-1) and a control (T0) that has not gone through the dehydration treatment. Analysis of pH, Total Titratable Acidity (TTA) were performed in mEq L-1, Total Soluble Solids (TSS) in ºBrix, water content on a dry basis and Concentration of Phenolic Compounds (CPC) in mg of gallic acid per 100g of must. The average comparison test identified statistically significant modifications for the adaptation of must for winemaking purposes, having the treatment with 22.9 ºC and air speed of 1.79 m s-1 shown the largest increase in the concentration of total soluble solids, followed by the second best result for concentration of phenolic compounds. Este estudo teve como objetivo verificar a influência da desidratação parcial de cachos de uva Niagara Rosada na qualidade físico-química do mosto pré-fermentativo. No Brasil, durante o processo de vinificação, é comum a necessidade de adequação do mosto de uvas quando as características físico-químicas da matéria-prima são insuficientes para a obtenção de vinhos em conformidade com a legislação brasileira para classificação de bebidas, a qual estabelece o teor alcoólico mínimo de 8,6% para que a bebida seja considerada vinho. Portanto, tendo em vista que a redução do teor de água das bagas da uva possibilita a concentração de compostos químicos presentes em sua composição, principalmente a concentração de sólidos solúveis totais, procedeu-se aos tratamentos que foram constituídos pela combinação de duas temperaturas (T1- 37,1 ºC e T2 - 22,9 ºC), duas velocidades de ar (V1- 1,79 m s-1 e V2-3,21 m s-1) e uma testemunha (T0), que não passou pelo tratamento de desidratação. Foram realizadas análises de pH, Acidez Total Titulável (ATT) em mEq L-1, Sólidos Solúveis Totais (SST) em ºBrix, teor de água em base seca e Concentração de Compostos Fenólicos (CCF) em mg de ácido gálico por 100 g de mosto. O teste de comparação de médias identificou modificações estatisticamente significativas para a adequação do mosto no intuito de vinificação, tendo o tratamento com 22,9 ºC e velocidade de ar de 1,79 m s-1 apresentado o maior incremento na concentração de sólidos solúveis totais, seguido do segundo melhor resultado para a concentração de compostos fenólicos.

Este trabalho apresenta um estudo com o qual se pretende comparar o resfriamento de laranja Valência (Citrus Sinensis Osbeck) em três sistemas: ar forçado, água gelada e em câmara de estocagem convencional. O sistema de resfriamento com ar forçado operou com um fluxo de ar de 1933 m³ h-1, a 1ºC e umidade relativa (UR) de 88,4% ± 2,0, com velocidade do ar em torno de 1 m s-1. Nos experimentos com água gelada foi utilizado um sistema de imersão, com capacidade de 0,23 m³ de água, a 1ºC. A câmara de resfriamento utilizada tinha capacidade de 2,90 J s-1. O tempo de meio e de sete oitavos do resfriamento foi determinado partindo-se das leituras da temperatura no centro dos frutos, com duas repetições. O resfriamento do leito de frutos com ar forçado não se mostrou homogêneo, obtendo-se tempos que variaram de 107 a 170 min, dependendo da posição do fruto no interior da embalagem. No sistema com água gelada o resfriamento acontece uniformemente em todo o leito de frutos, sendo o tempo médio de resfriamento de 57 min. Quando os frutos foram resfriados no sistema convencional, o tempo de resfriamento oscilou de 362 e 460 min, oito vezes maior que o obtido com água e três vezes maior com ar forçado.This work presents a study to compare the cooling of oranges with room cooling, forced-air cooling and hydrocooling systems of the Valência orange (Citrus Sinensis Osbeck). The forced-air cooling system operated with an air flow of 1933 m³ h-1, at 1ºC, relative humidity (RH) of 88.4% ± 2.0 and air velocity around 1 m s-1. In the experiments with cold water an immersion hydrocooling system with a capacity of 0.23 m³ of water was used at a temperature of 1ºC, approximately. The half cooling time and seven-eighths cooling time were determined from the temperature data, with two replications. The results showed that the cooling of the bed fruits with forced air is not homogeneous, obtaining a mean between 107 a 170 min, depending on the position of the fruit in the package. In the hydrocooling system, the cooling of the fruits occurs uniformly in the bed, with a mean cooling time of 57 min. In room cooling, the time of cooling was 362 and 460 min, eight times that of hydrocooling system and more than three times that of the forced air cooling time.

Neste trabalho apresenta-se um estudo numérico para a obtenção das curvas de resfriamento de laranja Valência, (Citrus sinensis O.) e banana prata (Mussa balbisiana Colla), em posições diferentes ao longo do leito e acondicionadas em embalagens com 40% de área efetiva de abertura. Os frutos foram resfriados num sistema de circulação com ar forçado (1.933m³/h), à temperatura de 1°C e 7°C, umidade relativa de 88,4 ± 2,0% e velocidade do ar em torno de 1m/s. Um modelo matemático bidimensional, em coordenadas esferoidais prolato, foi aplicado para predizer a condução de calor transiente dentro das frutas, assumindo-se condição de contorno convectiva na superfície do corpo. As equações geradas foram resolvidas numericamente pelo método de volumes finitos e o coeficiente convectivo de transferência de calor foi obtido aplicando o método de ajuste do erro quadrático mínimo, entre os dados experimentais e numéricos. A análise comparativa das curvas teóricas e experimentais mostrou uma concordância satisfatória, com valores de erro entre 5% e 7%. Notou-se que o coeficiente de transferência de calor varia com a posição dos frutos no leito e que o tempo de resfriamento apresenta uma variação de aproximadamente 38% entre os diferentes pontos. A distribuição espacial de temperatura no interior dos frutos, para três instantes de tempo, demonstrou a existência de um diferencial de temperatura entre o centro e a superfície de aproximadamente 30%. O modelo matemático prediz que a taxa de resfriamento nas bananas é muito mais alta nas pontas que nas outras regiões do fruto. O número de Bi e de Fo mostraram-se adequados e representativos do processo estudado, caracterizando adequadamente o resfriamento de corpos em qualquer relação de área/volume diferente.This paper presents a numerical study for obtaining cooling curves of orange Valência (Citrus sinensis O.) and banana Prata (Mussa Balbisiana Colla), in different positions along the bed and conditioned in package with 40% of effective opening area. The fruits were pre-cooled in a forced-air system (1.933m³/h), at 1°C and 7°C, RH= 88,4 ± 2,0% and air velocity around 1m/s. A two-dimensional mathematical model was applied, assuming prolate spheroid coordinate, to characterize the transient heat transfer process inside the fruits considering convective profile conditions at the surface of the body. The generated equations were numerically solved by finite-volume method. The convective heat transfer coefficients were obtained using the least square method by comparison between experimental and numerical data. The comparative analysis of the theoretical and experimental curves presented a satisfactory agreement, with error between 5% and 7%. It was noted that the convective heat transfer coefficient changes with the fruits position in the bed and cooling time present a variation of approximately 38% among the different points. The spatial distributions of temperature inside the fruits, for three times, demonstrate the existence of a temperature differential between the center and the surface of 30%, approximately. The model predicts that the cooling rate is in the extremes of the banana. The Bi and Fo numbers obtained represent very well the heat transfer process in the fruits under different relationships of volume/area.

A refrigeração é um excelente método para o armazenamento prolongado de produtos frescos. O uso de contêineres na agricultura é uma tecnologia simples e de fácil utilização que permite a manutenção da qualidade de produtos frescos, como frutas e hortaliças e a diminuição das perdas pós-colheita. Neste trabalho foram desenvolvidos uma série de experimentos com um contêiner frigorífico submetido a dois regimes de operação: vazio e com produto. Foram avaliadas as seguintes variáveis: temperatura, velocidade e umidade relativa do ar, além da pressão do sistema de refrigeração. Foi determinado o tempo de meio resfriamento de alface tipo americano (Latuca sativa L.), submetido a uma temperatura de 1ºC. Nas superfícies que recebem maior radiação solar o desvio da temperatura é de 1,5 ± 1ºC, com respeito às paredes que recebem menor radiação. A velocidade do ar variou de 2,1; 1,7 e 0,3 m/s, nos três planos estudados. O tempo de meio resfriamento da carga de alface variou entre 530 min (» 8 h), e 1.080 min (» 18 h), dependendo da posição das cabeças de alface no interior do contêiner. A umidade relativa do ar foi de 81-86% ± 1% e de 90-91 ± 1%, para o contêiner vazio e com carga, respectivamente.

The aim of this study was to perform an experimental study to evaluate the proper operation distance between the nodes of a wireless sensor network available on the market for different agricultural crops (maize, physic nut, eucalyptus). The experimental data of the network performance offers to farmers and researchers information that might be useful to the sizing and project of the wireless sensor networks in similar situations to those studied. The evaluation showed that the separation of the nodes depends on the type of culture and it is a critical factor to ensure the feasibility of using WSN. In the configuration used, sending packets every 2 seconds, the battery life was about four days. Therefore, the autonomy may be increased with a longer interval of time between sending packets. Um estudo experimental, visando a avaliar a distância de operação adequada entre os nós de uma rede de sensores sem fio disponível no mercado, foi realizado para diferentes cultivos agrícolas (milho, pinhão-paraguaio e eucalipto), buscando oferecer aos agricultores e pesquisadores dados experimentais do desempenho da rede, que possa good yield are environmental factors, which include high temperatures and high humidity within the facilities, causing stress to the animal and consequent decreased production (SOUSA, 2005).am ser úteis para ser considerados no dimensionamento e no projeto de redes de sensores sem fio em situações semelhantes às estudadas. A avaliação mostrou que a distância de separação dos nós depende do tipo de cultura e é um fator crítico para garantir a viabilidade do uso da RSSF. Na configuração usada, com envio de pacotes a cada 2 segundos, a autonomia da bateria foi de cerca de quatro dias. Portanto, a autonomia pode ser aumentada com um intervalo maior de tempo entre o envio de pacotes.

No Brasil, além da dificuldade na determinação do ponto ótimo de colheita, em muitos casos as características das cultivares de uvas utilizadas no processamento industrial causam a necessidade de adequação do produto, pois este é insuficiente para obter produtos conforme a resolução e principalmente com alto padrão de qualidade. Tendo em vista essa necessidade o objetivo deste estudo foi avaliar o efeito da secagem em dois níveis de temperatura na qualidade de uvas da cultivar “Niágara Rosada”. Como o principal objetivo da secagem é a redução do teor de líquidos no produto, os resultados encontrados revelam que embora a redução de líquidos tenha sido baixa, a temperatura interferiu significativamente no metabolismo dos compostos químicos das uvas, o que é comprovado pelas alterações na composição físico-química do produto, como aumento médio de 2,9 pontos na concentração de sólidos solúveis e de 328,7 no teor de compostos fenólicos, no entanto não houve diferença estatística nestes parâmetros para os níveis de temperatura avaliados.

As perdas de produtos hortícolas no Brasil são significativas e dentre as causas cita-se o uso de caixas inadequadas e ausência da cadeia do frio. Propõe-se um método de projeto de caixas, baseado em simulação computacional, otimização e validação experimental, minimizando o volume de madeira, associado a aspectos estruturais, ergonômicos e distribuição da área de aberturas. Foram projetados e construídos três protótipos de caixas (ripas retas com diferentes configurações e área efetiva de abertura de 54% e 36%). A eficiência do resfriamento de mangas variedade Tommy Atkins (Mangifera Indica L.), foi avaliada determinando o tempo de resfriamento, acondicionando as frutas nas caixas de madeira desenvolvidas e de papelão usadas comercialmente, resfriadas com ar forçado à temperatura de 6ºC e umidade relativa média de 85,4±2,1%. Foi aplicado o Método de Elementos Finitos, para dimensionamento e otimização estrutural do modelo com melhor comportamento durante o resfriamento. Todas as caixas de madeira foram submetidas a ensaios de vibração, por duas horas (freqüência de 20 Hz). Não houve diferença significativa no tempo de resfriamento das frutas nas caixas de madeira (38,00±1,70 min), no entanto houve diferença significativa nas caixas de papelão (82,74±29,58 min). O modelo submetido à otimização estrutural (6% área efetiva e duas ripas laterais) teve diminuição de volume de 60% e 83% de redução da seção transversal das colunas, com relação às condições iniciais. Não houve incidência de danos de mecânicos nas frutas após a vibração. A simulação computacional e estrutural pode ser ferramenta de apoio para desenvolver projetos de caixas, com grande aproximação, atendendo a critérios geométricos, ergonômicos e térmicos. Losses of horticulture product in Brazil are significant and among the main causes are the use of inappropriate boxes and the absence of a cold chain. A project for boxes is proposed, based on computer simulations, optimization and experimental validation, trying to minimize the amount of wood associated with structural and ergonomic aspects and the effective area of the openings. Three box prototypes were designed and built using straight laths with different configurations and areas of openings (54% and 36%). The cooling efficiency of Tommy Atkins mango (Mangifera Indica L.) was evaluated by determining the cooling time for fruit packed in the wood models and packed in the commercially used cardboard boxes, submitted to cooling in a forced-air system, at a temperature of 6ºC and average relative humidity of 85.4±2.1%. The Finite Element Method was applied, for the dimensioning and structural optimization of the model with the best behavior in relation to cooling. All wooden boxes with fruit underwent vibration testing for two hours (20 Hz). There was no significant difference in average cooling time in the wooden boxes (36.08±1.44 min); however, the difference was significant in comparison to the cardboard boxes (82.63±29.64 min). In the model chosen for structural optimization (36% effective area of openings and two side laths), the reduction in total volume of material was 60% and 83% in the cross section of the columns. There was no indication of mechanical damage in the fruit after undergoing the vibration test. Computer simulations and structural study may be used as a support tool for developing projects for boxes, with geometric, ergonomic and thermal criteria.

Este trabalho propõe um método de projeto de embalagem para produtos hortícolas, buscando uma otimização integrada dos aspectos geométricos, estruturais e térmicos, ligados à facilitação do resfriamento e armazenamento refrigerado. Para o dimensionamento e otimização estrutural, foi utilizado o Método dos Elementos Finitos implementado pelo programa ANSYS, obtendo-se oito modelos virtuais de embalagens, com 10% e 14% de área efetiva de aberturas e geometria quadrada, retangular e circular. Para o desenvolvimento dos experimentos, que avaliaram a relação da área de aberturas com o tempo de sete-oitavos de resfriamento, foram construídos protótipos de tábuas de madeira (Pinnus elliotti) de reflorestamento. Nas embalagens, foram acondicionados aproximadamente 13 kg de banana variedade Nanica (Musa cavendishii, cultivar nanica), resfriada num túnel de ar forçado (vazão de ar de 0,32 m³ s-1, temperatura de 8,0±1,2ºC e umidade relativa de 84,5±2,6%). O tempo de resfriamento também foi comparado com aquele obtido quando a mesma quantidade de frutas foi resfriada em embalagens de papelão (2,5% de área efetiva de abertura) e madeira (18% de área efetiva de abertura). Os resultados demonstraram que, entre os protótipos propostos, não houve diferença significativa no tempo de resfriamento dos frutos acondicionados nas embalagens desenvolvidas, sendo o tempo médio de resfriamento de 40,71±2,81 min. Na comparação com as embalagens de papelão e madeira, houve diferenças significativas, sendo que as embalagens comerciais tiveram tempos de resfriamento de 1,25 e 2 vezes maiores. Concluiu-se que a simulação estrutural computacional, aliada a algoritmos de otimização, além de procedimentos experimentais ligados à cadeia do frio, são recursos promissores no auxílio de projetos para embalagens de transporte de produtos hortícolas. This study proposes a methodology for designing boxes for agricultural products based on computational simulation and experimental validation, seeking the integrated optimization of geometric, structural and thermal aspects associated with cooling and refrigerated storage. The Finite Element Method was used for structural dimensioning and optimization. It was implemented using the ANSYS program, obtaining eight virtual models with 10% and 14% of effective opening area with square, rectangular or circular geometry. In order to develop the experiments that evaluated the relation between effective opening area and seven-eighths cooling time, the prototypes were built using reforestation wood (Pinnus elliotti). Approximately 13 kg of bananas (Musa cavendishii cultivar nanica) were packed in the boxes and cooled in a forced-air tunnel (air flow of 0.32 m³ s-1, temperature of 8.0±1.2ºC and relative humidity of 84.5±2.6%). Cooling time was also compared with the one obtained when the same amount of bananas was cooled in the boxes used to transport and store bananas commercially (cardboard box with 2% of effective opening area and a wooden box called " torito" with 18% of effective opening area). The results showed no significant differences in cooling time of bananas packed in boxes with circular, square and rectangular opening, with average cooling time of 40.71±2.81 min. However, when compared with cardboard and torito boxes, there was a significant difference in cooling time of 1.25 to 2 times the time obtained with wooden boxes. In the structural optimization of the EC-60 box (twelve 60 mm in diameter side orifices and 10% of effective opening area); material volume was reduced in 67.3% in relation to the project initial conditions. In compression tests, the box rupture occurred at loads between 5.4 kN and 8.1 kN, values 3 to 4 times heavier than the imposed project condition (2.0 kN). The computational simulation with optimization algorithms associated with cooling time experiments are promising resources to help in the box design for transporting products.

In slaughterhouses, the operations that occur are heavily dependent on electricity . This study aimed to diagnose, analyze and propose solutions that lead to the rational use of electricity, without interfering, or maintain, the quality of the final product on the production lines of a broiler slaughterhouse. The work was carried through in a slaughterhouse of broilers, located in Sao Paulo, in the period of 2004 to 2008 . It was found that the compressors responsible for maintaining cold the refrigerated environment showed the highest consumption of electricity in the fridge, representing 97% of total consumption . It was observed that in none of the evaluated electric motors the power factor reaches the value recommended by ANEEL, and that possibly the energy efficiency indicators can be optimized . It was concluded that there are failures in electric energy use, demonstrating the need to implement an action plan that aims the conservation and rational use of energy and consequent reduction in production cost of chicken meat. Keywords: Electrical Energy Consumption, Indicators, Rational Use, Slaughterhouse. DIAGNOSIS OF THE USE OF ELECTRIC ENERGY IN A CHICKEN SLAUGHTERHOUSE RESUMO: Nos matadouros , as operacoes que ocorrem sao altamente dependentes da eletricidade. Este estudo teve como objetivo diagnosticar, a nalisar e propor solucoes que levem ao uso racional de energia eletrica, sem interferir, e manter, a qualidade do produto final nas linhas de producao de frangos de corte matadouro. O trabalho foi realizado em um matadouro de frangos de corte , localizada em Sao Paulo, no periodo de 2004 a 2008. Verificou-se que os compressores responsaveis pela manutencao da frio do ambiente refrigerado apresentaram o maior consumo de electricidade no frigorifico , o que representa 97 % do consumo total. Foi observado que em nenhum dos motores eletricos avaliados o fator de potencia atinge o valor recomendado pela ANEEL, e que , possivelmente, os indicadores de eficiencia energetica pode ser otimizado. Concluiu-se que existem falhas no uso da energia eletrica , demonstrando a necessidade de implementar um plano de acao que visa a conservacao e uso racional de energia e consequente reducao do custo de producao de carne de frango . Palavras-chave: Consumo de Energia Eletrica , Indicadores, Uso Racional , Matadouro .

Se presenta un modelo matematico tridimensional transitorio aplicado al fenomeno de difusion de calor y materia con reduccion de volumen en el interior de solidos paralelepipedos. El modelo se ha aplicado al proceso de secado de ladrillos ceramicos. Se uso el metodo de los volumenes finitos considerando propiedades termicas y mecanicas constantes y una condicion de contorno convectiva en la superficie del material. El modelo fue utilizado para estudiar el proceso de secado de un ladrillo de ceramica a temperaturas de 60 y 80oC y en con humedades relativas del aire de 10,07 y 4,66%. Los resultados numericos de contenido de humedad, temperatura y reduccion de volumen, fueron comparados con datos experimentales para determinar los coeficientes de transporte. Se pudo concluir que: el fenomeno de reduccion de volumen tiene dos periodos y afecta considerablemente la velocidad de secado del solido, asi como la distribucion del contenido de humedad en el interior del mismo.

The cooling of fruits and vegetables in hydrocooling system can be a suitable technique. This work aimed to define cooling time for fruits and vegetables of different sizes, presenting practical indexes that could be used to estimate cooling time for produce with similar characteristics. Fruits (orange melon-Cucumis melo, mango-Mangifera indica, guava-Psidium guajava, orange-Citrus sinensis Osbeck, plum-Prunus domestica, lime-Citrus limon, and acerola-Prunus cerasus) and vegetables (cucumber-Cucumis sativus, carrot-Daucus carota, and green bean-Phaseolus vulgaris), were cooled in a hydrocooling system at 1°C. The volume of fruits and vegetables ranged between 8.18 cm³ and 1,150.35 cm³, and between 13.06 cm³ and 438.4 cm³, respectively. Cooling time varied proportionally to produce volume (from 8.5 to 124 min for fruits, and from 1.5 to 55 min, for vegetables). The relationship between volume and time needed to cool fruits (from 1.03 min cm-3 to 0.107 min cm-3) and vegetables (from 0.06 min cm-3 to 0.12 min cm-3) is an index that could be used to estimate cooling time for fruits and vegetables with similar dimensions as those presented in this work.

Este trabalho apresenta um estudo para comparar o resfriamento rápido de laranja Valência (Citrus sinensis O.), com ar forçado e com água gelada. O sistema de resfriamento rápido com ar forçado operou com um fluxo de ar de 1.933m³/h (3 l/s por kg de produto resfriado), a uma temperatura de 1ºC e UR=88,4 ± 2,0%, com uma velocidade do ar em torno de 1m/s. Nos experimentos com água gelada foi utilizado um sistema de imersão, com uma capacidade de 0,23m³ de água a uma temperatura de aproximadamente 1ºC. Foi determinando o tempo meio e de sete oitavos do resfriamento, partindo das leituras de temperatura, perfazendo-se duas repetições em cada experimento. Os resultados mostraram que, o resfriamento do leito de frutas com ar forçado não é homogêneo, obtendo-se um tempo de sete oitavos do resfriamento que variaram de 107min a 170min, dependendo da posição do fruto no interior da embalagem. Já no sistema com água gelada, o resfriamento acontece uniformemente em todo em todo o leito de frutos, sendo o tempo médio de resfriamento de 57min. This work presents a study to compare the orange Valência (Citrus sinensis O.) cooling with forced-air cooling and hydrocooling. The forced-air cooling system operated with air flow of 1933m³/h, at 1ºC, RH= 88,4 ± 2,0% and air velocity around 1m/s. The experiments with immersion hydrocooling systems with capacity of 0,23m³ of water at 1ºC, approximately. The half-cooling time and seven-eighths cooling time, they are determinate with the temperature data, made two repetitions. The results showed that the cooling the bed fruits, with air cooling, is not homogeneous, and obtained cooling time average, between 107min and 170min, depending on the position the fruit in the package. In the hydrocooling system, the cooling of the bed fruits happens uniformly in the bed, with average cooling time of 57min.

Este trabalho apresenta um estudo para determinar os custos do resfriamento de laranja Valência (Citrus Sinensis Osbeck) num sistema com ar forçado (Ta=1ºC e UR=88,4±2,0%) e numa câmara convencional. Os frutos foram resfriados condicionados em dois tipos de embalagens, com área efetiva de abertura de 3,5% e 40%. O custo total anual foi determinado com o cálculo dos custos fixos e variáveis da instalação, e o custo total de resfriamento, baseado na quantidade de frutos que podem ser resfriados em cada sistema, num mesmo período. Comprovou-se que o custo de resfriamento chega a ser de 20% a 40% menor quando os frutos são resfriados no sistema com ar forçado, se comparado com o custo quando os frutos foram resfriados no sistema convencional. This paper presents study of the cooling cost of Valencia orange in a forced-air system and room cooling (Ta=1ºC and RH = 88,4±2,0%).The fruits was conditioned in two package with 3,5% and 40% of opening effective area. The annual total cost was determined with the fixed and variable costs of the installation and the cooling total costs with the quantity of cooling products in the each system for the same period. The cooling total cost is the 40 to 20% smaller, if compared with the cost when the fruits cooling in the conventional room.