Takahisa Nishizu

Identification of Fluorescent Substance in Mandarin Orange Skin for Machine Vision System to Detect Rotten Citrus Fruits

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.

A Machine Vision System for Tomato Cluster Harvesting Robot

Abstract 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.

Helmholtz resonance technique for measuring liquid volumes under micro-gravity conditions

The Helmholtz resonance technique has been investigated for measuring liquid volumes under micro-gravity conditions. We proposed a theoretical model of the Helmholtz resonance phenomenon induced in a closed container, and carried out a micro-gravity experiment to confirm the applicability of the measurement technique using water as a test liquid. A swept frequency signal was added to a loudspeaker, and together, a microphone and the loudspeaker picked up the sound of the Helmholtz resonance. The liquid volume was calculated from the Helmholtz resonance frequency using an equation derived from the theoretical model. The liquid volume obtained from the micro-gravity experiment agreed well with the liquid volume obtained under terrestrial conditions. Thus, it was confirmed that the Helmholtz resonance technique was applicable for measuring liquid volume under micro-gravity conditions.

Liquid volume measurement for cryogen under microgravity condition

A Helmholtz resonance technique was employed as an effective technique for measuring volumes of cryogenic propellants in orbit. A closed-type resonator was developed and experiments that measured the volume of liquid nitrogen in micro-gravity conditions during parabolic flights were conducted. A loudspeaker installed in the resonator was driven by a swept sound from 249.5 to 649.5 Hz, and the response of the electrical impedance was analyzed by the maximum entropy method to determine the resonant frequency every 743 ms. The resonant frequencies obtained under the micro-gravity conditions agree with the data obtained under normal gravity conditions.

Determination of Egg Freshness and Internal Quality Measurement Using Image Analysis

Egg quality indices are related with freshness, size of air chamber, loss of weight, and viscosity of the yolk and the protein. However, since the described quality parameters require measured in a destructive way, it is not suitable to inspect the egg quality with complete enumeration. Therefore, this study was performed to investigate the potential of image analysis method for evaluation of internal egg quality. Samples of 90 fresh eggs were collected immediately after laying and stored up to 24 days. Five eggs were randomly drawn from each storage condition (packing vs unpacking) at a regular interval and loss of weight, specific gravity and size of air chamber were measured. The image analysis for nondestructive measurement of size of air chamber was also studied. Results showed that the egg weight and gravity gradually decreased with increasing of storage days, while the size of air chamber linear increased caused by evaporation of water through the shell. A relationship a between conventional method and the image analysis method for measuring the size of air chamber was developed with the correlation coefficient of 0.928. The new finding implied that image analysis might provide a useful nondestructive tool to assess internal egg quality.

Airflow resistance measurement for a layer of granular material based on the Helmholtz resonance phenomenon

A Helmholtz resonance technique was employed to predict the airflow resistance of layers of granular materials, namely glass beads, brown rice, soybean, adzuki beans, and corn kernels. Each granular sample was placed on the tube mouth of an open-type Helmholtz resonator. The resonant frequency was determined by measuring the electric impedance of a loudspeaker that was installed in the resonator and driven by a chirp signal linearly sweeping from 90 to 220 Hz for 6.0 s. For a changing sample layer thickness, the resonant frequency was measured, and the specific airflow resistance was calculated by measuring the static pressure drop required for N2 gas to flow through the layer at a constant velocity of 0.042 m/s. When the thickness of the layer was fixed, the Helmholtz resonant frequency decreased as the specific airflow resistance increased, regardless of the kind of granular material. Graphical Abstract A method of measuring the airflow resistance of a grain layer using an open-type Helmholtz resonator was proposed. The Helmholtz resonant frequency decreased as the specific airflow resistance increased, regardless of the kind of granular material.

Classification of the Stem Elongation Pattern in Ornamental Plants under Different Day and Night Temperature Conditions

Abstract 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.

A consideration on afterripening management of kiwifruits based on relation between fruit density and sugar content

A high precision non-destructive measurement technique for early kiwifruit sugar content estimation was proposed. Sugar contents of matured kiwifruits were estimated at harvest when the fruits were still immature. By estimating density of the immature fruit, starch content can be determined that was found closely related to sugar content of the fruit when it is fully matured. The fruit density was calculated from weight and volume information of the fruit. Considering the fact that the range of densities of kiwifruit is very narrow (about 1.02~1.06g/cm3), the measurement of volume requires high accuracy. In this study, the volume of about 2000 kiwifruits at harvest was measured with a Helmholtz acoustic resonance method that offered good correlation with a reference method with R2=0.9254, SEP=0.0019g/cm3. The fruit weight was measured with an electronic scale. The relationship between the fruit density at harvest and sugar content following ethylene treatment was also verified. The proposed system can be used for precision grading of kiwifruit quality based on prediction of sugar contents.

Effects of Dual Modification with Succinylation and Annealing on Physicochemical, Thermal and Morphological Properties of Corn Starch

The objective of this study was to investigate the effects of annealing, succinylation, and a dual modification process (succinylation–annealing) on the physicochemical, thermal, and morphological properties of corn starch. Specifically, the properties of interest were the water-binding capacity (WBC), swelling power, paste clarity, solubility, pasting properties, stability ratio, and thermal and morphological characteristics. The dual modification process increased the physicochemical properties (WBC, swelling power, peak viscosity, and paste clarity) and increased the gelatinization temperature and gelatinization enthalpy (∆H), but had no effect on the morphological properties and X-ray diffraction patterns. A comparison of samples, made using each of the processes, showed that dual modification increased the stability ratio (more stable viscosity under thermal and shear stress), which was 0.69 for dual modified starch, compared with 0.64, 0.58 and 0.44 for native, succinylated, and annealed starches, respectively. The findings of the present study are of potential use in the food industry.

Kinetic Analysis of Freeze-Thaw Stability of Mayonnaise

Kinetic analysis was used to study the destabilization of mayonnaise by focusing on the fat crystals. Mayonnaise prepared from rapeseed oil and soybean oil was stored at temperatures ranging from −20 to −40 °C. The destabilization kinetic parameters were measured by observing oil separation over time. The destabilization rate constant, kd, increased with decreasing temperature. The highest value of kd was 1.28 × 10−3 min−1 at −40 °C for rapeseed oil mayonnaise (RoM) and the lowest was 1.95 × 10−6 min−1 at −20 °C for soybean oil mayonnaise (SoM). At each temperature, the kd value in RoM was higher than that in SoM. However, the order of destabilization, n, followed no specific pattern. The crystallization rate constant, Kc, and Avrami constant, n, were calculated using microscopic images of the fat crystals. The increase in crystallization kinetic parameters with decreasing temperature revealed changes in crystal behavior. Both the destabilization rate constant, kd, and the crystallization rate constant, Kc, depended on the temperature. This temperature dependency behavior showed a correlation between kd and Kc, suggesting that the destabilization rate depended on the rate of growth of fat crystals during the freeze-thawing of mayonnaise.