Itsuo Yamaura

Discussing reflecting model of yarn

Purpose – This paper deals with the reflecting rays of yarn.Design/methodology/approach – The modeling, assuming that the fibers are arranged around the surface of elliptic yarn and reflecting rays of yarn are consisted of reflecting rays of fibers, is established using mathematical method. We can get a distributional curve of reflecting rays by this method.Findings – It was found that because resolution was an important parameter in measurement equipment, the result of modeling must be filtered. It gives fundamental theory for selecting resolution and we also provide other useful value for selecting equipment of image processing. Resolution is an important parameter for measurement equipment. We have provided the minimum resolution for yarn. When we do image processing for yarn, we can get correct information of yarn by image processing with the minimum resolution and over.Research limitations/implications – The result using different measurement equipment does not show the same result, therefore, the mo...

Vector locus of an equivalent radius of the root in growing plants

Tree planting on arid land is taken up as one of the measures against global warming prevention. It is important for the tree planting to grasp growth state of the root after planting. To monitor the root advancement, a method measuring electric ground impedance of the root has been presented. By this method, we can know the growth state without digging the soil. To estimate the value of impedance, we introduce a concept of an equivalent radius. In this method, the value of ground impedance is converted to a radius of the disk electrode that has the same value as the object. Moreover, ground impedance of the root is indicated as complex number, which consists of resistance and capacity components of the root. The equivalent radius is also expressed by complex number. We propose the method indicating the change of equivalent radius as growing of the root by means of vector locus. It is demonstrated by the experiments on sunflower and kenaf during one summer that the present method is useful for estimating the growth state of the plant root.

An estimation method of ground resistance of trees growing in different lands

It is important to monitor the growing state of tree roots without digging the soil away from the bottom of the tree. Electrical ground resistance of tree roots indicates the grade of the growing state. The better roots advanced in the ground, the smaller the value of ground resistance becomes. However, ground resistance of the tree is modified by resistivity of the soil. If the growing state of roots is the same in trees growing in different lands, the value of ground resistance of each tree shows different values according to soil resistivity where trees are growing. This disables the comparison of the growth level between different lands, and complicates the estimation of results. In order to make comparison possible between the two without the effect of soil resistivity, the value of ground resistance of the tree is converted to that of a metal disk electrode. Here, if we know the soil resistivity, a radius of the disk becomes to be known. This disk radius is called equivalent radius that can indicate the growth level according to its value regardless of soil resistivity. Using the equivalent radius, we can estimate the growth level of plants growing in different lands evenly. Measured equivalent radii and the ratios to their butt radius of objective trees in West Australia, Hawaii Island, and Japan are summarized in figures.

A measurement method of grounding impedance of a tree

This paper describes a method for measuring the grounding impedance of a tree. Electrode impedance of an electrode using for connection between the measurement circuit and the tree, brings serious error in the measurement. To avoid the effect of the electrode impedance, the four-electrode method known in the impedance measurement methodology, is newly introduced. The hybrid method of the four-electrode method and usual grounding impedance measurement method makes it possible to measure grounding impedance of the tree directly. The experiments of the measurement were conveyed for three materials, zelkova tree, cherry tree, and silk-tree with the girth of 1.7-2.0 meters. Obtained values of impedance were 60-100 O in absolute one, and they showed slight capacitive reactance. It is concluded that the presented method is available for the measurement of grounding impedance of the tree.

An Evaluation Method of Ground Resistance of a Tree.

It is important to monitor the growing state of tree roots without digging the soil away from the bottom of the tree. Ground resistance of tree roots indicates the grade of the growing state. However, ground resistance of the tree is modified by resistivity of the soil. This disables the comparison of the growth level of trees in different places. In order to make the comparison possible among them without influence of soil resistivity, the value of ground resistance of the tree is converted to that of a metal disk electrode. If we know the soil resistivity, a radius of the disk becomes to be known. This disk radius is called the equivalent radius. Using the equivalent radius, we can estimate the growth level of trees growing in different places evenly. The results of field studies on some trees are shown.

Simultaneous measurement of the botanical tissue impedance and the electrode impedance by the multi-electrode method

We provide a multi-electrode method for measuring the bulk impedance of botanical tissues and electrode impedance used in the measurement, simultaneously. By stabbing many electrodes in the object along the circumference of the columnar body, the bulk impedance and impedance of electrodes can be measured. The impedance of the botanical body can be estimated when the number of electrodes is infinite. The experimental results applied to Japanese radish showed the usefulness of the proposed method.