A very small (0.021 kg) grain yield sensor, comprising an octagonal ring load cell and an impact plate was developed for easily mounting onto grain combines used in East Asian countries. During the interval when the sensor is receiving no impact from the grain, the signals are averaged to determine the instantaneous zero-point; thus the sensor compensates for its own long-term drift. The sensor was mounted on a two-row jidatsu combine, and the weight of grain in the grain tank was estimated in the field experiment. The relative error in the validation without compensation was 19%, whereas that with the compensation decreased to 1.5%. The recommendable range of the threshold for detecting the impact was 0.5 to 4 times the root-mean squared average of the output without throughput of grain.
The influence of day temperature (DT) and night temperature (NT) on the stem elongation rate (SER) in chrysanthemum was investigated. SER in the light period was small and almost the same under all DIF conditions, in contrast, SER in the dark period was enhanced as DIF increased. When DT changed with a constant NT, SER in the light period was not statistically changed and SER in the dark period increased as DT increased. On the other hand, when NT varied with a constant DT, SER in the light and dark periods showed little change. From these results, it became clear that DT strongly influenced SER during subsequent nights in chrysanthemum.
As basic research to develop a machine vision system to detect rotten mandarin orange, the extraction and identification of fluorescent substances contained in rotten parts of mandarin orange were conducted, and the excitation and fluorescence wavelengths of the substance were determined. Although it has been reported that damaged orange fruit skins are often fluoresced by UV light, it was suggested that fluorescent substances exist not only in the rotten parts of skins but also the normal parts of skins from this research. The fluorescent substances were extracted from 1kg of mandarin peel, and NMR analysis and mass spectrometry were conducted. From this experiment, it was found that the fluorescent substance was quite possibly heptamethylflavone and that the excitation and fluorescent wavelengths of one of the substances were 360 to 375nm and 530 to 550nm, respectively.
Dutch style greenhouse for tomato production has become popular recently in many countries while cluster tomatoes have gained popularity among consumers. To improve harvest efficiency of the cluster tomatoes in large scale Dutch production systems, it is desirable to replace manual labor with automated machines. In this paper, a machine vision system developed for autonomous tomato fruit cluster harvesting is described. Since the difficulty of recognizing the grasping point depended on exposure of plant parts and on robot access angle, acquired images were classified into three groups. The research results show a 73% success rate in automatically locating grasping points for the robotic end-effector on main stems of the cluster tomatoes that can be visually identified by human eyes.
A new method is proposed for soil improvement of salt-affected soils in regions where a sufficient amount of rainfall occurs in summer. The subsoil is made coarse by soil sintering, and the capillarity from groundwater is cut off. In this paper, basic experiments of soil sintering were conducted, based on the thermophysical properties of the salt-affected soils reported in previous papers. The results show that when the soil layer is deep, a long time is required for complete sintering. For instance, the time for the temperature at the 0.04 m in depth to reach maximum (960°C ) was 278 hr. This is fundamental fault of soils whose thermal conductivity (800°C) is small (e.g., 0.1 Wm-1K-1) and thermal diffusivity (800°C) is also small (e.g., 1.19×10-7 m2s-1). The soil should be dry as much as possible when sintering. If the soil water content decreased to 8.7% d.b. (dry) from 26.6% d.b. (wet), the required heating time to reach 960°C at the soil surface was saved to about 200 s from about 500 s.
We investigated the pattern of stem elongation in response to temperatures in the light and dark periods in 6 bedding plants and 2 potted plants. The plants that responded well to different day and night conditions (DIF) could be classified into 2 groups. In the first group comprising plants Northpole and Verbena, the stem elongated mainly in the light period, and in the second group comprising plants chrysanthemum and Habotan, the stem elongated mainly in the dark period. Moreover, in the case of Zinnia, which exhibited an opposite reaction to DIF, stem elongation was observed in the dark period as the temperature increased. In the case of French marigold, Snapdragon, and Stock, which were not affected by DIF, stem elongation was not observed even when the temperature in the light and dark periods was varied.