Energy saving is an important issue for greenhouse farming. Natural and sustainable energy sources are critical to energy conservation. In this study, greenhouse heating and cooling technology was developed using a heat pump system that used surplus air thermal energy (SATE) and underground water thermal energy (UWTE) as heat sources. The greenhouse system was operated during February and March 2012. The SATE and UWTE system was successfully utilized for heating. Temperature control between desired set-points was also achieved. The heat pump system performed at average COP of 3.25 and 2.84 in February and March, respectively. In conclusion, greenhouse energy conservation was achieved by utilizing SATE and UWTE.
The objective of this research was to develop an autonomous picking robot system for greenhouse-grown tomatoes, which consists of four major components: the end-effector, machine vision, robot carrier, and control system. The graphical programming language LabVIEW ver. 7.1 was employed to develop the image processing and control system. The experimental results showed the success rates of the integrated picking were 94.83 %, 91.83 %, and 89.63 %, respectively. The average picking time needs about 35.96 s/sample, with a throughput of 100.1 samples/h. Consequently, an autonomous picking robot system was successfully developed and it needs to be further tested for real tomato picking operations in greenhouses in the future.
A novel continuous-flow polymerase chain reaction (PCR) chip has been analyzed. It operates by cycling a prepared sample within three temperature zones. Two temperature zones are controlled by two thermal controllers and the other is controlled by the flow rate of the fluid inside a cooling channel under a glass chip. The chip system consists of the reaction PDMS chip, a cover glass chip, a cooling channel, and is equipped with cartridge heaters and thermocouples for temperature control. Commercial software is utilized to determine the chip materials that are responsible for creating the denaturation, annealing and extension temperature zones within the chip. Therefore we utilize this chip to perform PCR experiments. Results show that DNA templates are amplified successfully.
A serious problem in Japanese agriculture is the aging and shortage of farm laborers. Agricultural robots are expected to solve or alleviate this problem, as well as provide additional information about agricultural products. In this research, we focus on machine vision for an asparagus harvesting robot. Although TV cameras are often used for machine vision in harvesting robots, it is difficult to use them in direct sunlight, due to fluctuations in illumination intensity and color temperature effects of sunlight. So a laser sensor was used. This sensor detected asparagus spears based on their distance from sensor and their length. Total success rate of detection was 75 % of asparagus spears and 71 % of parent asparagus.
In this study iPLS regression was used to select the efficient spectral regions and variables to develop a calibration model for L-ascorbic acid (L-AA) determination using FTIR-ATR terahertz (THz) spectroscopy. The objectives of using iPLS were to improve the prediction performance of L-AA determination and to show mapping of contribution of high and low frequency in determining L-AA. The result obtained by iPLS model with 5 PLS factors was superior than that of full-spectrum PLS model with 10 PLS factors when 7 spectral regions and 70 variables were selected. Prediction performance of L-AA can be improved by using iPLS model with higher ratio prediction to deviation (RPD) value.
The usefulness of a ground-based sensor embedded on tractor for monitoring the growth of winter wheat using a two plant nutrition active sensors (CropSpec) and RTK-GPS was investigated in this study. In order to consider the reliability of the results, the winter wheat was cultivated in farm land of Hokkaido University. Four levels of N fertilizer were applied to make differences in crop conditions, and growth information was acquired at four growth stages. A strong correlation (R2 > 0.70) for Nitrogen Sufficiency Index (S1 value) and ground truth data was found in the second stage of data collection. Also, a strong relationship (R2 > 0.90) between in-season estimation (INSE) of S1 value and other vegetation indices acquired using a spectroradiometer as a passive sensor demonstrated good performance of CropSpec. However, for diagnosis of crop growth condition for variable rate application, use of the S1 value without elimination of different measurement times is recommended.
The spatial and temporal variability of root-water uptake from the soil remain unclear due to the limitations of the measuring method and subsequently difficult in attempting to accurately model the soil-plant-atmosphere system. In this study, an experimental setup was designed to collect the data needed to develop a more realistic plant water uptake model using a modified subsurface irrigation system that allows the change of soil moisture content. The plant uptake response was determined from evapotranspiration, water consumption and soil moisture content at different soil depths. A plant water uptake model was reviewed and an extension of this model was proposed for the modified subsurface irrigation system. Preliminary investigation was performed using the experimental data and the results were essential.
This microwave-driven vehicle receives microwave power from a system with a magnetron and a parabolic antenna. Running paths, vehicle power consumption, turning angle, and the parabolic antenna depression angle were measured to assess the transmitting system orientation control. The system detects the vehicle position and turns the parabolic antenna to the vehicle. However, the maximum rotation speed of the transmitter turntable was 8.04° /s for a 2 m distance. The transmitter can follow the vehicle at speeds up to 0.14 m/s, but the maximum vehicle speed was 0.26 m/s with the microwave power supply. The low microwave electricity reception efficiency (ca. 5 %) was nevertheless higher than in earlier experiments using a horn antenna instead of a parabolic antenna.
The objective of this paper was to provide the development of on-the-go soil sensor for rice transplanter, particularly from a perspective of precision agriculture applications. Ultrasonic sensor, electrodes and platinum resistance thermometer were employed for topsoil depth (TD) and apparent electrical conductivity (ECa) measurement. Soil fertility value (SFV) defined as new soil parameter, which consisted of ECa / TD. The results of field test revealed that the developed equipments could measure the TD (R2 = 0.999), and the SFV had a strong relationship with measured EC (R2 = 0.937).