A Study on the Bandwidth Reduction of the Stiffness Matrix of a Framed Structure

How to give the numerical number for joints of a framed structure in order to reduce the bandwidth of its stiffness matrix, has been studied and a number of methods have been proposed already. Though the minimum bandwidth is wholly governed by the connectivity relationship between joints, only a few studies have taken that fact into the consideration. The connectivity relationship of a framed structure can be sufficiently shown by the use of a linear graph, which is composed of nodes and lines. Its characteristics can be understood by introducing the concept of graph theory. In this paper, the authors propose a graphical method to obtain the minimum bandwidth of tree structures. This is a kind of statically determinate system including no closed path, by the application of some definitions in graph theory. By use of the this sequential file method, all the nodal sequences are efficiently filed along the longest nodal sequence among the graph. The number of rows of filed nodal sequences present the bandwidth of the original structure

Structural Analysis and Design of Rigid Frames Based on Plastic Theorem

This paper is concerned with the plastic analysis and the design problems of multistory rigid frames by use of the linear programming technique. The objective of this work is to develop the plastic analysis and design of rigid frames, paying attention to the graph theory, and to reduce the computer core size and also to save the execution time by using a decomposition technique. A few examples are presented to illustrate the method proposed here

An Application of Network-Topological Concepts to the Design of Framed Structures

In accordance with the increasing necessity of the rational design of structures, the optimum design method has been developed during the last two decades. The optimum design method eventually depends on two different bases by using digital computers. One refers to the mathematical programming, while the other refers to the structural analysis to be suitable for digital computations. There exist, however, many difficulties in their direct applications to the optimum design. Numerical results occasionally converge poorly and more calculation time is required as the number of design variables increases. Thus, a particular treatment which can decrease the number of design variables is necessary for the design of real large structures. In this paper, the authors propose the piecewise design, which is based on the concepts of Kron's Tearing and Interconnecting Method, in order to decrease the number of design variables. Also, the optimal geometric configuration, which has been scarcely considered in most studies, is discussed with the aid of the topological treatment

A Network-Topological Study on Statical Analysis of Rigid Framed Structure

After the studies of G.H. Kron, who applied the network theory to structural analysis, many investigations in this field were done. They are the analysis by analogy of framed structures to electrical circuits, and the purpose of these studies is to establish the effective formulations of framed structural analysis, with respect to the Network-Topological properties of structures which are suited to the numerical analysis by use of the digital computer which requires systematic notation- and calculation methods. In the network-topological analysis of electrical circuits, there are two basic different methods, i.e. “Node Method” and “Mesh Method”. As a variation of “Node Method”, the “Tree Method” exists. In the structural analysis, the two basic methods are already formulated as “Displacement Method” and “Force Method” respectively, but the last one is not used. When these methods are used for the analysis of large structures by use of computer, there arise many problems, which are the problems of the capacity of the computer and also that of calculation-time. To decrease the difficulties of these problems, the method of tearing and interconnecting of the structure is used. In this paper, a tearing and interconnecting method by an information, which is got from Incidence Matrix, is presented. And the application of Tree Method in the problems of electric circuits to the structural analysis and a tearing and interconnecting method for it by successive application of the Housholder's formula is also considered

Studies of Mint Breeding III : Induced Polyploid of Japanese Mint (Mentha arvensis L. var. piperascens MAL.) by the colchicine method.

1.日本薄荷｢赤茎｣の幼苗の生長点をコルヒチン処理して人為倍数体植物を育成した.その処理個体の自殖による第2代植物3個体について形態並びに生理的形質の調査と核学的観察を試み,母本,日本薄荷のそれと比較した. 2.育成倍数体は細胞,組織,器官において巨大性を示したが,生育が遅れ,開花初は9月末乃至10月初で,母本,日本薄荷より約1ヶ月遅れた｡3.母本,日本薄荷は 2n=96,MIで48IIを示し,成熟分裂は正常,4分子の形成にも異常はなかつた.育成倍数体は2n=192,n=96でMIには2価染色体の他に8～14個の4価染色体が認められ,そのmodeは10であつた.併し核分裂に異常なく,正常な4分子を形成した. 4.成熟分裂及び4分子形成が正常であるにかかわらず,完全に発育した葯中の稔性花粉の割合は,母本,育成倍数体共に50～60%で大差なかつた.併し完全葯の出現頻度は,倍数体では母本に比べて非常に少かつた.受精率も母本に比べて低かつた. 5.育成倍数体の種子の発芽率は,母本,日本薄荷のそれと大差なかつたが,発芽には約3倍の日数を要した. 6.薄荷属は12を基本染色体数とする.日本薄荷は8倍体,而も種々の点から異質8倍体と推定する理由がある.従つて筆者等の育成した倍数体薄荷は16倍体と考えられる. 7.育成倍数体茎葉の精油含有率及び精油中の遊離メントール含有率は,これを直ちに利用出来る程の高い価を示さなかつた.併し此の方法による育種の可能性は十分に認められた

大麦うどんこ病菌(Erysiphe graminis DC. f. sp. hordei)の地理的分化

Fifteen cultures of barley powdery mildew fungus (Erysiphe graminis DC. f. sp. hordei) isolated in different regions of the world were inoculated to 120 barley varieties. Infection scores varied among the cultures and barley varieties, and their interactions were observed. Principal component analysis of the infection scores revealed that the cultures could be classified into three groups by first and second components (contributing 40.2% and 15.6% of the total variance, respectively), and that two Japanese cultures could be distinguished from the others isolated in Europe and North America. This indicates that the fungus is geographically differentiated in the reaction of the barley varieties to the cultures. Furthermore, East Asian barley varieties differed from European ones in their reactions to the culltures, while barley varieties from regions between East Asia and Europe showed a large genetic diversity in their reactions.オオムギは世界的に広く栽培され、形態的・生理的特性を支配する遺伝子が地理的に規則性をもって分布している。そこで、本研究ではオオムギに罹病するオオムギうどんこ病菌の地理的分化を知るために、世界の異なる地域から採集した15菌系をオオムギ120品種に接種し、それらの反応を調査した。病原性は菌系によって、また、感受性はオオムギ品種によって著しく異なり、菌系と品種との相互作用が認められた。そこで、15菌系に対する120品種の反応を肉眼観察によって、8階級に分け、その値を主成分分析法によって解析した。第1主成分と第2主成分で全体の分散の55％以上を説明することが可能であり、これらの菌系は第1および第2主成分によって3群に分類することができた。供試した菌系についてみると、日本の3菌系のうち2株系は他のものと明らかに異なり、残りの1菌系はイスラエルや欧米の菌系と類似していた。さらに、欧米の菌系は2群に細分することができた。このことから、うどんこ病菌にも地理的な分化が生じているとみることができる。さらに、オオムギ品種をうどんこ病菌系に対する反応から分類してみると、東アジアの品種は欧州のものと明らかに異なり、オオムギの起源地である西南アジアの品種は極めて多様性に富んでいた