Research

17 pages, 6218 KiB

Open AccessArticle

A Simulation and Experiment of the Flow Fluctuation Characteristics of a Fertilizer Distribution Apparatus with a Screw from the Perspective of the Force Chain

by Mengqiang Zhang, Hao Niu, Yuchen Han, Yi Zhi, Tianhao Yuan, Hong Zhang, Yichuan He, Zhihui Tang and Haipeng Lan

Appl. Sci. 2024, 14(3), 1122; https://doi.org/10.3390/app14031122 - 29 Jan 2024

Viewed by 472

Abstract

To investigate the causes of flow fluctuations in a worm-type distributor during the fertilization process, this study employed the discrete element method to simulate the fertilization process. The analysis focused on the influences of force chain evolution on particle flow fluctuations and the [...] Read more.

To investigate the causes of flow fluctuations in a worm-type distributor during the fertilization process, this study employed the discrete element method to simulate the fertilization process. The analysis focused on the influences of force chain evolution on particle flow fluctuations and the effects of the rotational speed. The results indicate that the flow fluctuations in the worm-type distributor are not solely attributed to its helical structure but are closely associated with the evolution of force chains within the particle systems. Furthermore, a one-to-one correspondence between the flow fluctuations and force-chain evolution exists. The rotational speed was found to exert significant influences on the axial and circumferential distributions of the force chains. As the rotational speed increases, the coefficient of variation (CV) of the axial distribution of the force chains gradually decreases. Meanwhile, the uniformity index (UI) of the circumferential distribution of the force chains initially increases and then decreases. In the context of a worm-type distributor, the axial distribution of force chains emerges as the dominant influencing factor for flow fluctuations. For the specific worm-type distributor model chosen in this study, the minimum flow fluctuations were observed at a rotational speed of 80 rpm. These research findings offer valuable insights into understanding the flow fluctuations of worm-type distributors and provide references for further exploration in this field. Full article

(This article belongs to the Special Issue Advances in Technology Applied in Agricultural Engineering)

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14 pages, 5847 KiB

Open AccessArticle

Advanced Preprocessing Technique for Tomato Imagery in Gravimetric Analysis Applied to Robotic Harvesting

by Nail Beisekenov and Hideo Hasegawa

Appl. Sci. 2024, 14(2), 511; https://doi.org/10.3390/app14020511 - 06 Jan 2024

Viewed by 960

Abstract

In this study, we improve the efficiency of automated tomato harvesting by integrating deep learning into state-of-the-art image processing techniques, which improves the accuracy and efficiency of detection algorithms for robotic systems. We develop a hybrid model that combines convolutional neural networks’ dual [...] Read more.

In this study, we improve the efficiency of automated tomato harvesting by integrating deep learning into state-of-the-art image processing techniques, which improves the accuracy and efficiency of detection algorithms for robotic systems. We develop a hybrid model that combines convolutional neural networks’ dual two-dimensional matrices for classification and part affinity fields. We use data augmentation to improve the robustness of the model and reduce overfitting. Additionally, we apply transfer learning to solve the challenging problem of improving the accuracy of identifying a tomato’s center of gravity. When tested on 2260 diverse images, our model achieved a recognition accuracy of 96.4%, thus significantly outperforming existing algorithms. This high accuracy, which is specific to the environmental conditions and tomato varieties used, demonstrates the adaptability of the model to real-world agricultural conditions. Our results represent a significant advancement in the field of agricultural autotomization by demonstrating an algorithm that not only identifies ripe tomatoes for robotic harvesting with high accuracy, but also adapts to various agricultural conditions. This algorithm should reduce manual labor in agriculture and offer a more efficient and scalable approach for the future agricultural industry. Full article

(This article belongs to the Special Issue Advances in Technology Applied in Agricultural Engineering)

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17 pages, 10076 KiB

Open AccessArticle

Design and Experiment of an Electric Control Spiral-Pushing Feed Mechanism for Field Fertilizer Applicator

by Guoqiang Dun, Xingpeng Wu, Xinxin Ji and Yuhan Wei

Appl. Sci. 2023, 13(23), 12628; https://doi.org/10.3390/app132312628 - 23 Nov 2023

Viewed by 712

Abstract

Due to the unique structural characteristics of the traditional spiral fertilizer applicator, the instantaneous filling coefficient cannot be determined, which is not conducive to achieving precise control of the fertilizer discharge rate. Therefore, a spiral-pushing fertilizer applicator has been designed. By using a [...] Read more.

Due to the unique structural characteristics of the traditional spiral fertilizer applicator, the instantaneous filling coefficient cannot be determined, which is not conducive to achieving precise control of the fertilizer discharge rate. Therefore, a spiral-pushing fertilizer applicator has been designed. By using a structure of variable diameter and variable spiral pitch to squeeze fertilizer gradually, precise control of the fertilizer discharge is achieved. The study analyzes the effects of screw pitch, screw diameter, and rotational speed on the filling coefficient; it uses spiral pitch elongation percentage, spiral diameter elongation percentage, and rotational speed as experimental factors, and filling coefficient and particle axial velocity coefficient as experimental indicators. Through quadratic orthogonal rotation combination design experiments, the fertilizer discharge performance of the spiral-pushing fertilizer applicator was optimized. The experimental results indicate that for the filling coefficient, x₁x₂ has an extremely significant impact, while for the axial velocity coefficient of particles, x₁ and x₃ have an extremely significant impact. When the rotational speed x₃ is 30 r/min, the optimized spiral pitch elongation percentage x₁ is 189.82–200%, the spiral diameter elongation percentage x₂ is 102.75–106.76, the filling coefficient is greater than 95%, and the particle axial velocity coefficient is less than 10%, achieving the best fertilizer discharge performance. An electrically controlled fertilizer discharge system was also designed, and bench tests were conducted on it. The results show that the average deviation between the fertilizer discharge performance of the spiral-pushing fertilizer applicator driven by the electrically controlled fertilizer discharge system and the preset value is 2.14%. This proves that, when the fertilizer demand changes, the fertilizer discharge flow can be adjusted through the electrically controlled fertilizer discharge system to achieve precise fertilization. This study provides a reference for the design of spiral fertilizer applicators. Full article

(This article belongs to the Special Issue Advances in Technology Applied in Agricultural Engineering)

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15 pages, 6572 KiB

Open AccessArticle

Eco-Design and Additive Manufacturing of an Innovative Double-Casing Pedometer for Oestrus Detection in Dairy Cow

by Simona Maria Carmela Porto, Michele Calì and Marco Bonfanti

Appl. Sci. 2023, 13(21), 11725; https://doi.org/10.3390/app132111725 - 26 Oct 2023

Viewed by 1045

Abstract

The analysis of motor activity has been revealed to be essential for monitoring dairy cows’ behavior, with the main aim of identifying the onset of oestrus in time. Pedometers used for oestrus detection have a current average working life on the market of [...] Read more.

The analysis of motor activity has been revealed to be essential for monitoring dairy cows’ behavior, with the main aim of identifying the onset of oestrus in time. Pedometers used for oestrus detection have a current average working life on the market of about 5 years. At the end of that period, devices are disposed of, posing a relevant question regarding environmental sustainability. The present work proposed a method to achieve an eco-design of pedometers compliant with the guidelines of the Green Deal. Specifically, a new thermo-plastic organic compound made of polyamide 66 reinforced with organic hemp fibers (trade name SDS Nylon) was adopted. The feasibility, benefits, and performance of this material were assessed with a major emphasis on strength, lightweight, and surface finish. The material in addition to ensuring adequate chemical and mechanical resistance is biocompatible and recyclable. It assures better animal welfare and reduces both environmental impacts and management costs for farmers. Other innovations introduced in this study consisted of the adoption of a double casing. An external case was conceived with a protective function of the measurement system and fixed to a cow’s foreleg by an easy anchor system. An internal case was specifically designed to house the electronic components and to be moved from one cow to another after the pregnancy diagnosis. The solutions proposed in this research will contribute to guaranteeing pedometers a longer lifetime and better recyclability than existing commercial ones, consequently limiting the environmental load derived from their disposal. Full article

(This article belongs to the Special Issue Advances in Technology Applied in Agricultural Engineering)

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17 pages, 18682 KiB

Open AccessArticle

A Study of Apple Orchards Extraction in the Zhaotong Region Based on Sentinel Images and Improved Spectral Angle Features

by Jingming Lu, Weiwei Song, Xiaoqing Zuo, Daming Zhu and Qunlan Wei

Appl. Sci. 2023, 13(20), 11194; https://doi.org/10.3390/app132011194 - 11 Oct 2023

Viewed by 804

Abstract

Zhaotong City in Yunnan Province is one of the largest apple growing bases in China. However, the terrain of Zhaotong City is complicated, and the rainy weather is more frequent, which brings difficulties to the identification of apple orchards by remote sensing. In [...] Read more.

Zhaotong City in Yunnan Province is one of the largest apple growing bases in China. However, the terrain of Zhaotong City is complicated, and the rainy weather is more frequent, which brings difficulties to the identification of apple orchards by remote sensing. In this paper, an improved spectral angle feature is proposed by combining the Spectral Angle Mapper and Sentinel-1 data. Based on the Google Earth Engine and Sentinel image, a random forest classifier was used to extract apple orchards in the Ganhe Reservoir area, Zhaoyang District, Zhaotong City, which provides a theoretical basis for extracting the spatial distribution and sustainable development of the local apple industry. The classification results show that the improved spectral angle characteristics can improve the overall accuracy and F1 score of apple orchards. The RGB band combined with NDVI, GLCM, and improved spectral angle features obtained the most favorable results, and the F1 score and overall accuracy were 88.89% and 84.44%, respectively, which proved the reliability of the method in identifying apple orchards in Zhaotong City. Full article

(This article belongs to the Special Issue Advances in Technology Applied in Agricultural Engineering)

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22 pages, 6479 KiB

Open AccessArticle

Contributions to the Process of Calibrating Corn Seeds Using a Calibrator with Cylindrical Sieves

by Iuliana Găgeanu, Gabriel Gheorghe, Cătălin Persu, Nicolae-Valentin Vlăduț, Dan Cujbescu, Mihai Gabriel Matache, Iulian Voicea, George-Cătălin Ion, Ana-Maria Tăbărașu, Sorin Petruț Boruz and Lorena-Diana Popa

Appl. Sci. 2023, 13(17), 9927; https://doi.org/10.3390/app13179927 - 02 Sep 2023

Viewed by 779

Abstract

This paper presents theoretical and experimental research on the process of calibrating corn seeds using a specialized equipment with cylindrical sieves, studying the influence of process parameters and corn seed particularities on the quality of the calibration work. The research took into consideration [...] Read more.

This paper presents theoretical and experimental research on the process of calibrating corn seeds using a specialized equipment with cylindrical sieves, studying the influence of process parameters and corn seed particularities on the quality of the calibration work. The research took into consideration corn seed characteristics, namely, their dimensions (length, width, and thickness) and weight, determining the influence of process parameters—the contact point between the seed and the cylindrical sieve, the influence of the length of the sieve, and the sieve’s revolution speed on the separation process. The experiments for determining the influence of these parameters on the calibration process were conducted on a calibrating equipment with cylindrical sieves using three different corn hybrids. It was noticed from the experiments that, overall, the revolution speed had the most important effect on the calibration process, with sieve length also affecting the process, but to a lesser degree. Seed calibration efficiency was best at the smallest revolution speed (33 rot/min) and decreased when the revolution speed increased up to 49 rot/min for all corn hybrids tested. The number of calibrated seeds decreased in the second part of the cylindrical sieve. Seed thickness influenced the process, in the respect that seeds smaller than 4.8 mm passed through the first third of the sieve and those with a thickness between 4.8 and 5 mm passed through the other two thirds of the sieve length. Full article

(This article belongs to the Special Issue Advances in Technology Applied in Agricultural Engineering)

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20 pages, 6613 KiB

Open AccessArticle

Spatial, Temporal, and Vertical Variability of Ambient Environmental Conditions in Chinese Solar Greenhouses during Winter

by Md Nasim Reza, Md Nafiul Islam, Md Zafar Iqbal, Md Shaha Nur Kabir, Milon Chowdhury, Md Ashrafuzzaman Gulandaz, Mohammod Ali, Moon-Ki Jang and Sun-Ok Chung

Appl. Sci. 2023, 13(17), 9835; https://doi.org/10.3390/app13179835 - 30 Aug 2023

Cited by 2 | Viewed by 851

Abstract

The monitoring and control of environmental conditions are crucial as they influence crop quality and yield in Chinese solar greenhouses (CSGs). The objectives of this study were to assess the spatial, temporal, and vertical variability of major environmental parameters in CSGs during winter [...] Read more.

The monitoring and control of environmental conditions are crucial as they influence crop quality and yield in Chinese solar greenhouses (CSGs). The objectives of this study were to assess the spatial, temporal, and vertical variability of major environmental parameters in CSGs during winter and to provide greenhouse climate/microclimate characteristics in order to facilitate the monitoring and control of greenhouse environmental conditions. A wireless sensor network (WSN) was deployed in two CSGs: one with crops and one without. Sensors were placed at different locations inside and outside the greenhouses, and the air temperature, humidity, CO₂ concentration, light intensity, solar radiation, and wind conditions were measured and analyzed. Significant variability in the spatial, temporal, and vertical distribution of environmental factors was observed in both greenhouses. The average minimum and maximum temperatures and humidity inside the CSG with crops were 9.96 °C (4:00 h) and 24.5 °C (12:00 h), and 32.6% (12:00 h) and 92.1% (5:00 h), respectively. The temperature difference was 2.2 °C between layers in the CSG without crops and 1.4 °C between layers in the CSG with crops. The CO₂ concentration in the different layers inside the CSG with crops was highest at night. The average maximum light intensity inside the CSG with crops was 32,660.19 lx, 36,618.12 lx, and 40,660.48 lx (12:00 h to 13:00 h) in the bottom, middle, and top layers, respectively. Sensor positioning in the greenhouse was evaluated by considering the sensors’ data variability. The findings of this study could aid in the development of a better monitoring and control system for CSG’s microclimate during winter. More research is needed on greenhouse microclimate control systems based on this variability analysis, which could improve crop quality and yield in greenhouses. Full article

(This article belongs to the Special Issue Advances in Technology Applied in Agricultural Engineering)

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20 pages, 1441 KiB

Open AccessArticle

Crop Prediction Model Using Machine Learning Algorithms

by Ersin Elbasi, Chamseddine Zaki, Ahmet E. Topcu, Wiem Abdelbaki, Aymen I. Zreikat, Elda Cina, Ahmed Shdefat and Louai Saker

Appl. Sci. 2023, 13(16), 9288; https://doi.org/10.3390/app13169288 - 16 Aug 2023

Cited by 12 | Viewed by 18773

Abstract

Machine learning applications are having a great impact on the global economy by transforming the data processing method and decision making. Agriculture is one of the fields where the impact is significant, considering the global crisis for food supply. This research investigates the [...] Read more.

Machine learning applications are having a great impact on the global economy by transforming the data processing method and decision making. Agriculture is one of the fields where the impact is significant, considering the global crisis for food supply. This research investigates the potential benefits of integrating machine learning algorithms in modern agriculture. The main focus of these algorithms is to help optimize crop production and reduce waste through informed decisions regarding planting, watering, and harvesting crops. This paper includes a discussion on the current state of machine learning in agriculture, highlighting key challenges and opportunities, and presents experimental results that demonstrate the impact of changing labels on the accuracy of data analysis algorithms. The findings recommend that by analyzing wide-ranging data collected from farms, incorporating online IoT sensor data that were obtained in a real-time manner, farmers can make more informed verdicts about factors that affect crop growth. Eventually, integrating these technologies can transform modern agriculture by increasing crop yields while minimizing waste. Fifteen different algorithms have been considered to evaluate the most appropriate algorithms to use in agriculture, and a new feature combination scheme-enhanced algorithm is presented. The results show that we can achieve a classification accuracy of 99.59% using the Bayes Net algorithm and 99.46% using Naïve Bayes Classifier and Hoeffding Tree algorithms. These results will indicate an increase in production rates and reduce the effective cost for the farms, leading to more resilient infrastructure and sustainable environments. Moreover, the findings we obtained in this study can also help future farmers detect diseases early, increase crop production efficiency, and reduce prices when the world is experiencing food shortages. Full article

(This article belongs to the Special Issue Advances in Technology Applied in Agricultural Engineering)

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20 pages, 2714 KiB

Open AccessArticle

Combined Effects of Different LED Light Recipes and Slow-Release Fertilizers on Baby Leaf Lettuce Growth for Vertical Farming: Modeling through DoE

by Francesco Barbieri, Silvia Barbi, Alessandro Bertacchini and Monia Montorsi

Appl. Sci. 2023, 13(15), 8687; https://doi.org/10.3390/app13158687 - 27 Jul 2023

Cited by 1 | Viewed by 1026

Abstract

The modern agriculture system based on open-field crops requires a lot of energy and resources in terms of soil, water, and chemicals. Vertical farming (VF) systems could be a viable alternative for some types of cultivation that are receiving interest thanks to their [...] Read more.

The modern agriculture system based on open-field crops requires a lot of energy and resources in terms of soil, water, and chemicals. Vertical farming (VF) systems could be a viable alternative for some types of cultivation that are receiving interest thanks to their high modularity, optimized water and nutrients use, and LEDs employment as an energy-efficient light source. However, VF design and installation are expensive and require well-tailored optimization depending on the specific crop to increase its competitiveness. This work analyzed the effects of different combinations of NPK (nitrogen-phosphorus-potassium) slow-release fertilizers and LED-based light recipes on the growth of baby leaf lettuce (Lactuca sativa L.), taking advantage of the Design of Experiments (DoE) methodology. The type of slow-release fertilizer, its quantity measured as the number of aggregates from 0 to 6, and the type of light recipe were considered as input factors, and their possible influence on the growth of lettuce (in terms of morphological parameters) in a controlled indoor farming system was measured. Results suggest that using higher fertilizer inputs equal to six aggregates leads to an increase of average leaf area equal to 46% (from 13.00 cm² to 19.00 cm²), while the fresh weight of lettuce increases by 65% (from 1.79 g to 2.96 g). However, the height of plants also depends on the combination of the light recipes. In particular, the separate coupling of higher inputs of two fertilizers and light recipes leads to an increase in the height of lettuce equal to 33% (from 6.00 cm to 8.00 cm). Full article

(This article belongs to the Special Issue Advances in Technology Applied in Agricultural Engineering)

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17 pages, 8842 KiB

Open AccessArticle

Experimental Design and Validation of an Adjustable Straw Guide Structure for a Grain Combine Harvester Thresher Based on a Material Movement Model

by Luofa Wu, Daogen Chen, Xieqing Xu and Yanqi Wu

Appl. Sci. 2023, 13(14), 8476; https://doi.org/10.3390/app13148476 - 22 Jul 2023

Viewed by 1150

Abstract

The threshing device is the core component of the grain combine harvester, and the straw guide board plays an important role in the threshing device. In the past, the guiding structure of the threshing device could not optimize the working performance of the [...] Read more.

The threshing device is the core component of the grain combine harvester, and the straw guide board plays an important role in the threshing device. In the past, the guiding structure of the threshing device could not optimize the working performance of the machine by adjusting the spiral angle. In this study, an adjustable straw guide board was designed, and the movement model of the straw on the straw guide board was analyzed. The response surface method was used to perform field experiments, and the experimental data were analyzed using quadratic polynomial regression. The results show that the drum rotation speed, operating speed, and spiral angle of the straw guide board have significant effects on the percentage of loss rate (PLR), percentage of impurities rate (PIR), and percentage of broken rate (PBR). Further optimization analysis showed that the predicted values of the PLR, PIR, and PBR were 1.18%, 0.72%, and 0.54%, respectively, whereas the experimental verification values were 1.26%, 0.73%, and 0.61%, respectively. The absolute errors between the experimental and predicted values were very small; however, the optimized field test verified values decreased by 8.31%, 50.04%, and 60.30%, respectively, which indicates that the optimized harvester had better operation quality. Full article

(This article belongs to the Special Issue Advances in Technology Applied in Agricultural Engineering)

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13 pages, 1851 KiB

Open AccessArticle

Study on Low Temperature Drying Characteristics of Chicken Manure in a Humid Environment

by Xuanyang Li, Xiangtao Kang, Lei Xi, Qi Dou and Zhifang Shi

Appl. Sci. 2023, 13(13), 7957; https://doi.org/10.3390/app13137957 - 07 Jul 2023

Cited by 1 | Viewed by 840

Abstract

Drying chicken manure with exhaust air from a chicken house is a new manure management method developed in recent years. The majority of the heat for this drying method comes from the waste heat of ventilation in a poultry house or ambient air, [...] Read more.

Drying chicken manure with exhaust air from a chicken house is a new manure management method developed in recent years. The majority of the heat for this drying method comes from the waste heat of ventilation in a poultry house or ambient air, so the drying process is carried out at a low temperature. When met with continuous rain or when the wet curtain in the chicken house is turned on, the relative humidity of the exhaust air from the chicken house will rise to high levels, and the drying process will be under the condition of high relative humidity. In order to explore the low-temperature drying characteristics of chicken manure in a humid environment, drying experiments were carried out in an experimental cross-flow drying system. The experiment mainly studied the effect of process parameters such as drying temperature, air velocity, and manure layer thickness on the low-temperature drying characteristics of chicken manure in a humid environment. The results showed that the low-temperature drying process of chicken manure in a humid environment only had a falling rate period, with no accelerated or constant rate period. Additionally, five common thin-layer drying models (Lewis model, Page model, Henderson and Pabis model, Wang and Singh model, and Exponential model) were applied to simulate the performance of the manure drying process. The exponential model was considered to be more suitable for describing the low temperature drying process in a humid environment, and the effective diffusivity changed between 6.37 × 10⁻⁷ and 2.17 × 10⁻⁶ m²/h. Full article

(This article belongs to the Special Issue Advances in Technology Applied in Agricultural Engineering)

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19 pages, 12971 KiB

Open AccessArticle

Remote Sensing for Sustainable Pistachio Cultivation and Improved Quality Traits Evaluation through Thermal and Non-Thermal UAV Vegetation Indices

by Raquel Martínez-Peña, Sergio Vélez, Rubén Vacas, Hugo Martín and Sara Álvarez

Appl. Sci. 2023, 13(13), 7716; https://doi.org/10.3390/app13137716 - 29 Jun 2023

Cited by 6 | Viewed by 1316

Abstract

Pistachio (Pistacia vera L.) has earned recognition as a significant crop due to its unique nutrient composition and its adaptability to the growing threat of climate change. Consequently, the utilization of remote sensing techniques for non-invasive pistachio monitoring has become critically important. [...] Read more.

Pistachio (Pistacia vera L.) has earned recognition as a significant crop due to its unique nutrient composition and its adaptability to the growing threat of climate change. Consequently, the utilization of remote sensing techniques for non-invasive pistachio monitoring has become critically important. This research was conducted in two pistachio orchards located in Spain, aiming to assess the effectiveness of vegetation indices (VIs) in estimating nut yield and quality under various irrigation conditions. To this end, high-resolution multispectral and thermal imagery were gathered using a Micasense ALTUM sensor carried by a DJI Inspire 2 drone in order to calculate the NDRE (normalized difference red edge index), GNDVI (green normalized difference vegetation index), NDVI (normalized difference vegetation index), and CWSI (crop water stress index). Each orchard underwent two flights at distinct growth stages, totaling four flights. In June, NDRE-carbohydrates (r = 0.78) and CWSI-oleic (r = 0.77) showed the highest correlations, while in September, CWSI-carbohydrates (r = 0.62) and NDVI-iron (r = 0.54) Despite NDVI’s limitations due to saturation effects, all VIs had significant yield and quality correlations, with GNDVI proving most effective in both flights. CWSI correlated considerably on both dates in terms of several quality parameters (carbohydrate percentage, magnesium, iron, and fatty acids, namely palmitoyl, stearic, oleic, and linoleic), surpassing non-thermal indices. Finally, it is important to consider the impact of environmental factors, such as the location of the sun, when interpreting the CWSI, as it modifies the temperature distribution pattern within the canopy. This study supports the viability of remote sensing and vegetation indices as potential tools for enhancing the management of pistachio orchards. Full article

(This article belongs to the Special Issue Advances in Technology Applied in Agricultural Engineering)

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14 pages, 3146 KiB

Open AccessArticle

Experimental Study on the Degradation of Acaricides on the Surface of Kumquat Cuimi by Nonthermal Air Plasma

by Si Qin, Shuo Chen, Xiaonan Wang, Yuanfu Zang, Zifeng Wang and Jie Wei

Appl. Sci. 2023, 13(13), 7560; https://doi.org/10.3390/app13137560 - 27 Jun 2023

Viewed by 602

Abstract

Nonthermal air plasma, which can be generated by air discharge, contains large amounts of reactive oxygen species (ROS), reactive nitrogen species (RNS) and high-energy particles. The ROS and RNS have strong oxidizing properties, and the high-energy particles can break chemical bonds in organic [...] Read more.

Nonthermal air plasma, which can be generated by air discharge, contains large amounts of reactive oxygen species (ROS), reactive nitrogen species (RNS) and high-energy particles. The ROS and RNS have strong oxidizing properties, and the high-energy particles can break chemical bonds in organic compounds, a process which can be used to degrade organic matter such as pesticides. In the present study, the effects of nonthermal air plasma on the degradation of several pesticides were investigated. An air plasma processing system was designed and constructed to produce nonthermal air plasma and to degrade five commonly used acaricides, namely, avermectin, bifenazate, spirodiclofen, etoxazole, and lufenuron, during the production of kumquat cuimi. The experimental results showed that nonthermal air plasma could degrade all the acaricides on the surface of the kumquat cuimi effectively. After 20 min of plasma treatment, the residues of avermectin, bifenazate, spirodiclofen, etoxazole and lufenuron on the surface of the kumquat cuimi were reduced by 80.67%, 79.52%, 62.40%, 48.93% and 23.11%, respectively. Further analysis indicated that the primary chemical bonds, hydrophobicity, and the pH value of the plasma-activated water can all affect the efficiency of pesticide degradation. Full article

(This article belongs to the Special Issue Advances in Technology Applied in Agricultural Engineering)

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14 pages, 3588 KiB

Open AccessArticle

Calibrating of a Simulation Model to Predict the Flexural Capacity of Pre-Stressed Concrete Beams

by Jesús Montero, Jorge Cervera-Gascó, Carlos Gilarranz and Santiago Laserna

Appl. Sci. 2023, 13(13), 7477; https://doi.org/10.3390/app13137477 - 25 Jun 2023

Viewed by 732

Abstract

Simulation models based on finite elements are currently indispensable tools for predicting the structural behavior of both reinforced and pre-stressed concrete elements. This work develops a simulation model of structural linear elements of pre-stressed concrete, using the finite element method (FEM). The main [...] Read more.

Simulation models based on finite elements are currently indispensable tools for predicting the structural behavior of both reinforced and pre-stressed concrete elements. This work develops a simulation model of structural linear elements of pre-stressed concrete, using the finite element method (FEM). The main aim was to calibrate the model to predict the flexural capacity of structural elements, and so be able to undertake a double optimization through the design and the resistant behavior of the elements. Different flexural experiments were conducted in laboratory conditions on real concrete elements of different types (pre-stressed joist and tubular pre-stressed joist). In parallel, the same structural elements were analyzed by MEF simulation to calibrate the model to the real experiments. FEM analysis was performed using the ATENA software developed by Červenka Consulting (Czech Republic), especially recommended for the analysis of structural concrete elements using non-linear methods. The model was calibrated using the results obtained in real load test experiments obtained in a loading frame of 500 kN capacity. The calibration analysis shows a good fit of the results to the actual test experiments, obtaining average errors of 6% in the analysis–experiment comparison. The results of the simulation suggest that to obtain the optimum strength levels for the different typologies analyzed, it is essential to control the pre-stressing losses in the manufacturing process of the joist. The flexural capacity of all elements can be increased by around 20–30% when the real pre-stressing losses are fitted to the theoretical ones estimated. Full article

(This article belongs to the Special Issue Advances in Technology Applied in Agricultural Engineering)

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13 pages, 2686 KiB

Open AccessArticle

Textile Physical Barriers: An Assessment of the Prison Effect as a Design Criterion to Increase the Porosity without Loss of Efficacy

by Antonio J. Álvarez and Rocío M. Oliva

Appl. Sci. 2023, 13(10), 6254; https://doi.org/10.3390/app13106254 - 19 May 2023

Viewed by 751

Abstract

Insect-proof screens are a physical method of crop protection against pests whose use is widespread. The hole size must be optimized since too small holes give rise to poorly porous textiles that cause a significant reduction in the permeability of the textiles to [...] Read more.

Insect-proof screens are a physical method of crop protection against pests whose use is widespread. The hole size must be optimized since too small holes give rise to poorly porous textiles that cause a significant reduction in the permeability of the textiles to air. A common design strategy is to use a rectangular-hole geometry with the aim of limiting the hole width to prevent insect entry and increasing the hole length to increase the hole surface. However, the validity of this approach has not been tested, and indications suggest that it may not be offering the expected results. The results obtained discredit this widely accepted design criterion since they show that, while the hole width is maintained, protective screens lose efficacy as the hole length increases at least in the range of values considered. It is not possible to find an explanation for these results by considering the hole geometry from a two-dimensional point of view. However, when considering the spatial arrangement of the threads, it is understood that the passage surface for the insects is larger than that considered in the orthogonal projection images and that as the hole length increases, the efficacy of the textiles decreases. Full article

(This article belongs to the Special Issue Advances in Technology Applied in Agricultural Engineering)

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21 pages, 5268 KiB

Open AccessArticle

Optimization of Glulam Regular Double-Tapered Beams for Agroforestry Constructions

by María Simón-Portela, José Ramón Villar-García, Desirée Rodríguez-Robles and Pablo Vidal-López

Appl. Sci. 2023, 13(9), 5731; https://doi.org/10.3390/app13095731 - 06 May 2023

Viewed by 2417

Abstract

This paper addresses the lack of attention paid by the scientific community to the optimization of timber structures, specifically in the context of large-span agro-industrial constructions. The study focuses on the optimization of a three-dimensional roof composed of GL32h glulam regular double-tapered beams [...] Read more.

This paper addresses the lack of attention paid by the scientific community to the optimization of timber structures, specifically in the context of large-span agro-industrial constructions. The study focuses on the optimization of a three-dimensional roof composed of GL32h glulam regular double-tapered beams and purlins. Firstly, MATLAB was employed to develop a calculation software and then run the proposed optimization model based on genetic algorithms, in order to optimize the different geometries of the construction elements based on cost, as well as the optimum arrangement of the purlins and the number of beams. Moreover, statistical analyses were carried out on more than 200 optimization data points to uncover the influence of different variables in the optimization process. It was found that the snow load and span have a significant influence on the prediction of the height and width of beams and purlins, as well as the purlin spacing; while, as expected, the roof length also influences the optimal number of beams. All these findings could promote the use of timber structures; thus, achieving more sustainable and efficient construction practices. Full article

(This article belongs to the Special Issue Advances in Technology Applied in Agricultural Engineering)

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18 pages, 3732 KiB

Open AccessArticle

Optimal Design and Experiment of Corn-Overlapped Strip Fertilizer Spreader

by Guoqiang Dun, Ning Mao, Xinxin Ji, Fuli Zhang and Wenyi Ji

Appl. Sci. 2023, 13(4), 2559; https://doi.org/10.3390/app13042559 - 16 Feb 2023

Cited by 4 | Viewed by 1825

Abstract

As the complex terrain in hilly areas is not conducive to corn mid-tillage precision fertilization, a corn-overlapped strip fertilizer spreader was designed without an external power source. By configuring a passive overlapping spreading method with a three-branch split chamber structure, the uniform spreading [...] Read more.

As the complex terrain in hilly areas is not conducive to corn mid-tillage precision fertilization, a corn-overlapped strip fertilizer spreader was designed without an external power source. By configuring a passive overlapping spreading method with a three-branch split chamber structure, the uniform spreading of fertilizer in strips was achieved. A horizontal and vertical movement model of fertilizer spreading was developed to determine the angle of the fertilizer extending tube, the width of fattening small plates, and the height of the fertilizer spread as the main factors affecting the fertilizer distribution pattern. The single-factor ternary orthogonal rotational combination response surface simulation test was carried out with pendulum angle, width, and height as test factors and the transversal fertilizer uniformity coefficient and longitudinal fertilizer uniformity coefficient as test indicators. The test results showed that the pendulum angle, height, and width had significant effects (p < 0.05) on the transversal fertilizer uniformity coefficient, and the pendulum angle and width had a considerable impact (p < 0.05) on the longitudinal fertilizer uniformity coefficient. In the optimal combination of parameters, swing angle 52°, height 400 mm, and width 50 mm operation, the coefficients of uniformity of both the transversal fertilizer uniformity coefficient and longitudinal fertilizer uniformity coefficient were less than 0.15%. A verification test was carried out under the optimal combination of parameters for the simulation tests with the simulation conditions as the standard. The test results were consistent with the simulation results within the error range. The deviation values of the transversal fertilizer uniformity coefficient and longitudinal fertilizer uniformity coefficient were 8.11% and 9.01%, respectively. The corn-overlapped strip fertilizer spreader was able to complete the fertilizer spreading operation smoothly. This study provides evidence for further optimizing the performance of the corn mid-tillage fertilizer applicator. Full article

(This article belongs to the Special Issue Advances in Technology Applied in Agricultural Engineering)

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15 pages, 3689 KiB

Open AccessArticle

Experimental Study of the Effect of Ultrasound on the Freezing Process of Bo Chinh Ginseng

by Minh-Hieu Ngo, Hay Nguyen, The-Bao Nguyen, Thanh-Dat Le and Quang-Huy Le

Appl. Sci. 2023, 13(1), 408; https://doi.org/10.3390/app13010408 - 28 Dec 2022

Cited by 2 | Viewed by 1399

Abstract

The main purpose of this study was to select the appropriate ultrasound parameters that support the freezing process of Bo Chinh ginseng. This process involves placing Bo Chinh ginseng in an open-air environment and ensuring that the transducer does not come into contact [...] Read more.

The main purpose of this study was to select the appropriate ultrasound parameters that support the freezing process of Bo Chinh ginseng. This process involves placing Bo Chinh ginseng in an open-air environment and ensuring that the transducer does not come into contact with the material. The research results show that the ultrasound power, ultrasound irradiation temperature and intermittency ratio all affect the freezing time, nucleation temperature, color and microstructure of the materials. When the ultrasound continuously operated during the freezing process, at a frequency of 20 kHz, there was a 29.1% reduction in the freezing time at a power level of 100 W as compared to freezing without the help of ultrasound irradiation. The irradiation temperature and nucleation temperature have a linear relationship (

y = - 0.35 x - 0.93

) which can help to control the nucleation temperature, thereby changing the ice crystal size. Ultrasound-assisted freezing at a 0.6 intermittency ratio had the shortest freezing time. The microstructure of the material changed after ultrasound-assisted freezing and many microchannels and holes were generated. When frozen at a wave rate of 0.4, the microchannels that were created in the material effectively supported the process of water drainage in the drying sublimation stage. At the same time, ultrasound irradiation did not affect the color of the post-freezing material when compared to the color of the frozen material that did not undergo ultrasound irradiation. Full article

(This article belongs to the Special Issue Advances in Technology Applied in Agricultural Engineering)

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