Template-Type: ReDIF-Article 1.0 Author-Name: Adebayo Olasunkanmi Salau Author-Workplace-Name: Department of Agricultural and Environmental Engineering, Faculty of Technology, Obafemi Awolowo University, Ile-Ife, Nigeria Author-Name: Babatunde Sunday Ogunsina Author-Workplace-Name: Department of Agricultural and Environmental Engineering, Faculty of Technology, Obafemi Awolowo University, Ile-Ife, Nigeria Author-Name: Adewale Waliu Adebayo Author-Workplace-Name: Department of Agricultural and Environmental Engineering, Faculty of Technology, Obafemi Awolowo University, Ile-Ife, Nigeria Author-Name: Adekunle Felix Okunade Author-Workplace-Name: Department of Agricultural and Environmental Engineering, Faculty of Technology, Obafemi Awolowo University, Ile-Ife, Nigeria Title: Thin layer drying characteristics of alligator pepper, ginger and turmeric Abstract: The delightful pungency, aromatic compounds and phytochemicals in some spices make them indispensable in local food systems and native medicine, hence, driving a robust market in many parts of the world. The understanding of their drying characteristics is very important for processing and adding value, and a thin layer drying study is a proven method for achieving this. In this study, changes in the moisture content, moisture ratio, drying rate and effective diffusivity of alligator peppers, ginger and turmeric were investigated at three drying temperatures 50, 60, and 70 °C following standard procedures. Five models were proposed to simulate the drying process. Non-linear regression was used to establish the coefficient of determination (R2), sum of square error (SSE) and root mean square error (RMSE) for each model to determine the model of the best fit. The Page model gave the best fit for ginger while the logarithmic model was best fitted for alligator peppers and turmeric. The effective diffusivity ranged from 1.79-3.08 × 10-9, 8.44-9.74 × 10-9, and 4.06-6.49 × 10-9 m2.s-1 for alligator peppers, ginger and turmeric, respectively. The activation energy ranged from 16.5-22 kJ.mol-1.K-1 for the three spices. These findings promise improvement in the drying, processing and handling of spices, thereby boosting the obtainable income from the value chain. Keywords: activation energy, effective moisture diffusivity, model fitting, moisture ratio Journal: Research in Agricultural Engineering Pages: 1-8 Volume: 69 Issue: 1 Year: 2023 DOI: 10.17221/71/2021-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/71/2021-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-202301-0001.txt Handle: RePEc:caa:jnlrae:v:69:y:2023:i:1:id:71-2021-RAE Template-Type: ReDIF-Article 1.0 Author-Name: Okechukwu Oduma Author-Name: Precious Ehiomogue Author-Workplace-Name: Department of Agricultural and Bioresources Engineering, Michael Okpara University of Agriculture, Umudike, Nigeria Author-Name: Dilibe Ifanyi Ntunde Author-Workplace-Name: Department of Mechanical Engineering, Michael Okpara University of Agriculture, Umudike, Nigeria Title: Model development and optimisation of the disc plough efficiency on loamy-sand soil in South-East Nigeria Abstract: This study was conducted to model and optimise the efficiency of a disc plough on loamy-sand soil in South-East Nigeria to aid farmers to examine and choose the right ploughing implement based on the soil type for an effective and bountiful production. The operational speed and cutting depth were taken as factors for the study of the plough efficiency. The results revealed that the highest field efficiency of 80% was noted when the plough worked at the cutting depth of 30 cm and a speed of 5 km.h-1 while the lowest efficiency of 68.10% was achieved at a speed of 9 km.h-1 and a depth of 10 cm. The quadratic model was significant for the response (P < 0.05). The results indicated that the coefficient of determination (R2) was 0.98, which specified the high correlation among the factors. The predicted R2 (0.76) was consistent with the adjusted R2 of 0.96. The adequacy precision of 24.89 showed a suitable indicator and that the model could navigate the design space. The optimum field efficiency and the desirability of 77.50% and 1.00 were, respectively, obtained at an optimum speed of 7 km.h-1 and a cutting depth of 30 cm. Farmers can, however, assess and select the implements with the aid of the developed model. Keywords: depth, farmers, implement, selection, speed Journal: Research in Agricultural Engineering Pages: 9-17 Volume: 69 Issue: 1 Year: 2023 DOI: 10.17221/72/2021-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/72/2021-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-202301-0002.txt Handle: RePEc:caa:jnlrae:v:69:y:2023:i:1:id:72-2021-RAE Template-Type: ReDIF-Article 1.0 Author-Name: Michal Jůza Author-Workplace-Name: Department of Agricultural Machines, Faculty of Engineering, Czech University of Life Sciences Prague, Prague, Czech Republic Author-Name: Petr Heřmánek Author-Workplace-Name: Department of Agricultural Machines, Faculty of Engineering, Czech University of Life Sciences Prague, Prague, Czech Republic Title: Influence of the excavator hydraulic system efficiency on the productivity Abstract: This paper presents the experimental research of factors influencing the UDS 214 excavator efficiency. The hydraulic oil flow rate is measured in hydraulic circuits for controlling the moving of the bucket of the UDS 214 ex­cavator. From the measured values, the total power losses of the individual hydraulic circuits and their efficiencies are evaluated by calculations and measurements. Furthermore, the times of the excavator cycles during a soil excavation and loading of the transport vehicle were measured. From the measured operating cycle times of the excavator, the average value of the operating cycle time was evaluated and, from this average time, the theoretical performance and the operating performance of the given excavator in the given operational states were calculated. Then, at the end of the paper, the individual calculated power losses as well as the efficiencies of the hydraulic circuits for controlling the moves of the excavator are evaluated. According to the findings, the swing hydraulic circuit of the excavator, which has the second highest power loss of 5.926 kW and its percentage in the average tested cycle time of the excavator is 48%, seems to be a suitable hydraulic circuit for the innovation. Keywords: flow rate, hydraulic circuit, power loss, pressure loss, pressure Journal: Research in Agricultural Engineering Pages: 18-27 Volume: 69 Issue: 1 Year: 2023 DOI: 10.17221/77/2021-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/77/2021-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-202301-0003.txt Handle: RePEc:caa:jnlrae:v:69:y:2023:i:1:id:77-2021-RAE Template-Type: ReDIF-Article 1.0 Author-Name: Tomáš Pícha Author-Name: Stanislava Papežová Title: Dielectric properties of materials for 3D printing at high frequencies Abstract: 3D printing is widely used method. In the term of developing of components for electronic devices, it is important to provide the good physical properties of the used dielectric. The main parameters are optional and stable value of the relative permittivity and the minimum dielectric losses of the material. The paper is focused on testing of loss factor and relative permittivity of following materials: polylactic acid (PLA, in two dye modifications), polyethylene terephthalateglycol (PET- G) and acrylonitrile butadiene styrene (ABS) in the frequency range of 1-100 MHz. It was proven, that the values of permittivity of the tested materials were 2.9-4.2 and loss factor 0.8-4%. Concerning relative permittivity, the tendency to mild linear drop of relation was observed by increasing frequency, especially expressed in PLA materials. In loss factor, PLA materials displayed increasing values with increasing frequency, whereas the declining curve was observed in PET-G. Absolute value of ABS loss factor varied between 0.9-1.5%. The reasonable influence of added dyes was found out. Keywords: ABS, fused deposition modelling (FDM), loss factor, PET-G, PLA, relative permittivity Journal: Research in Agricultural Engineering Pages: 28-35 Volume: 69 Issue: 1 Year: 2023 DOI: 10.17221/10/2022-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/10/2022-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-202301-0004.txt Handle: RePEc:caa:jnlrae:v:69:y:2023:i:1:id:10-2022-RAE Template-Type: ReDIF-Article 1.0 Author-Name: Christos Dimitrios Papanikolaou Author-Workplace-Name: Department of Agriculture, Crop Science and Rural Environment, Laboratory of Agricultural Hydraulics, University of Thessaly, Volos, Greece Author-Name: Maria Andreas Sakellariou-Makrantonaki Author-Workplace-Name: Department of Agriculture, Crop Science and Rural Environment, Laboratory of Agricultural Hydraulics, University of Thessaly, Volos, Greece Title: Estimation of corn coefficients with vegetation indices using multispectral camera and drone Abstract: Optimum irrigation scheduling and new technologies are the key to the successful practice of modern agriculture and natural resources, such as water management. Α three-year research project was conducted at Velestino, Magnesia, Greece. The aim was to study whether vegetation indices can be used to estimate the crop coefficients of corn in order to apply an intelligent method of irrigation using drones in the future. The normalised difference vegetation index (NDVI), the soil-adjusted vegetation index (SAVI), the renormalised difference vegetation index (RDVI) and a new index [difference infrared - green vegetation index (DIGVI)] were calculated using multispectral photos from a camera adapted to a drone. Three different methods were applied to calculate the crop coefficients: (i) the water balance and the FAO Penman-Monteith reference evapotranspiration, (ii) the climatic data, (iii) the vegetation indices. The irrigation dose covered 100% of the crop water needs according to the soil moisture measurements and the single crop coefficient values. The statistical analysis and the simple linear regression method showed that the corn crop coefficients can be estimated when these indices are used as independent variables. Keywords: crop monitoring, modern irrigation, reference evapotranspiration, remote sensing, spectral indices Journal: Research in Agricultural Engineering Pages: 36-47 Volume: 69 Issue: 1 Year: 2023 DOI: 10.17221/19/2022-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/19/2022-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-202301-0005.txt Handle: RePEc:caa:jnlrae:v:69:y:2023:i:1:id:19-2022-RAE Template-Type: ReDIF-Article 1.0 Author-Name: Natesan Kapilan Author-Name: Vijay Kumar Patil Title: Development and evaluation of a low-cost evaporative cooling system for agricultural product storage Abstract: Agricultural products are highly perishable and, hence, we need to preserve these products after harvest. India is an agricultural country and, thus, the post-harvest storage of perishable agricultural products is important to reduce the gap between the demand and supply. Cold storage technologies have been developed and are used in India; however, these technologies are not popular in rural and remote areas due to the higher initial cost and the electrical energy requirement. Therefore, a number of low-cost technologies have been developed and, among these technologies, the evaporative cooling technology is gaining in popularity due to its simple design and lower initial cost. In this work, we have developed and tested a solar photovoltaic (PV) powered evaporative cooling system and used coconut coir as the cooling medium and compared the results with celdex pad. From this work, we observed that this system is an economical and efficient in reducing the temperature and increasing the relative humidity for the storage of agricultural products. Keywords: agricultural products, evaporative system, performance, preservation, renewable energy Journal: Research in Agricultural Engineering Pages: 48-53 Volume: 69 Issue: 1 Year: 2023 DOI: 10.17221/41/2021-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/41/2021-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-202301-0006.txt Handle: RePEc:caa:jnlrae:v:69:y:2023:i:1:id:41-2021-RAE