49 research outputs found
The developmental process of flood shoals based on observations in Toufutsu lake, Japan
Recently, the flood tidal sand bars have been developed at the entrance channel of Toufutsu Lake located along Okhotsk Sea in Hokkaido, and they affect flood control, inland water fisheries in lake, and so forth. In this study, we aimed to reveal the developmental process of sand bars by observations, which are velocity observation, water level observation, bed material investigation and video monitoring. Followings were major accomplishments of this study. (1) The maximum magnitude of reverse velocity at St.400 in the entrance channel during the periods of flood-tide was faster than that of normal velocity during the periods of ebb-tide. (2) The relationship between velocity at SP400 and friction velocity at SP400 during the periods of flood-tide is different from that during the periods of ebb-tide. (3) The\ud
flood tidal sand bars at the entrance channel of Toufutsu Lake were developed by not only sea waves, but also adverse tidal current in the spring-tide
Groundwater management based on monitoring of land subsidence and groundwater levels in the Kanto Groundwater Basin, Central Japan
Over 40 million people live on and exploit the groundwater resources of the
Kanto Plain. The Plain encompasses metropolitan Tokyo and much of Chiba
Prefecture. Useable groundwater extends to the base of the Kanto Plain, some
2500 to 3000 m below sea level. Much of the Kanto Plain surface is at sea
level. By the early 1970s, with increasing urbanization and industrial
expansion, local overdraft of groundwater resources caused major ground
subsidence and damage to commercial and residential structures as well as to
local and regional infrastructure. Parts of the lowlands around Tokyo
subsided to 4.0 m below sea level; particularly affected were the suburbs of
Funabashi and Gyotoku in western Chiba. In the southern Kanto Plain,
regulations, mainly by local government and later by regional agencies, led
to installation of about 500 monitoring wells and almost 5000 bench marks by
the 1990's. Many of them are still working with new monitoring system.
Long-term monitoring is important. The monitoring systems are costly, but the
resulting data provide continuous measurement of the "health" of the Kanto
Groundwater Basin, and thus permit sustainable use of the groundwater
resource
Performance Analysis of 6 Slot 8 Pole Permanent Magnet Linear Motor
Currently, palm oil is the mostconsumedvegetable oilin the world. Therefore, an increment in its productivity is essential to ensure its sustainability in the market. One option is through the mechanization of the tools used to harvest it. In this paper, the design of the actuator for mechanized oil palm harvesting tools was discussed. A 3 phase permanent magnet linear motor with a 6 slot 8 pole structure topology known as 3PhSTLOA was used as the actuator structure. The structure of 3PhSTLOA has been optimized. The aim of the optimization is to allow the 3PhSTLOA to produce at least 200 N of average thrust at a total weight of under 2.0 kg. As a result of optimizing the 3PhSTLOA produced about 202 N of average thrust at 1.8 kg of its total weight. The performance of 3PhSTLOA is then compared with the previous type of actuator in mechanized harvesting tools
Entropy and equilibrium state of free market models
Many recent models of trade dynamics use the simple idea of wealth exchanges
among economic agents in order to obtain a stable or equilibrium distribution
of wealth among the agents. In particular, a plain analogy compares the wealth
in a society with the energy in a physical system, and the trade between agents
to the energy exchange between molecules during collisions. In physical
systems, the energy exchange among molecules leads to a state of equipartition
of the energy and to an equilibrium situation where the entropy is a maximum.
On the other hand, in the majority of exchange models, the system converges to
a very unequal condensed state, where one or a few agents concentrate all the
wealth of the society while the wide majority of agents shares zero or almost
zero fraction of the wealth. So, in those economic systems a minimum entropy
state is attained. We propose here an analytical model where we investigate the
effects of a particular class of economic exchanges that minimize the entropy.
By solving the model we discuss the conditions that can drive the system to a
state of minimum entropy, as well as the mechanisms to recover a kind of
equipartition of wealth
Large-scale structure of a nation-wide production network
Production in an economy is a set of firms' activities as suppliers and
customers; a firm buys goods from other firms, puts value added and sells
products to others in a giant network of production. Empirical study is lacking
despite the fact that the structure of the production network is important to
understand and make models for many aspects of dynamics in economy. We study a
nation-wide production network comprising a million firms and millions of
supplier-customer links by using recent statistical methods developed in
physics. We show in the empirical analysis scale-free degree distribution,
disassortativity, correlation of degree to firm-size, and community structure
having sectoral and regional modules. Since suppliers usually provide credit to
their customers, who supply it to theirs in turn, each link is actually a
creditor-debtor relationship. We also study chains of failures or bankruptcies
that take place along those links in the network, and corresponding
avalanche-size distribution.Comment: 17 pages with 8 figures; revised section VI and references adde
Diachronous beginnings of the Anthropocene: The lower bounding surface of anthropogenic deposits
Successful treatment of activated occult hepatitis B in a non-responder chronic hepatitis C patient
Boolean Dynamics with Random Couplings
This paper reviews a class of generic dissipative dynamical systems called
N-K models. In these models, the dynamics of N elements, defined as Boolean
variables, develop step by step, clocked by a discrete time variable. Each of
the N Boolean elements at a given time is given a value which depends upon K
elements in the previous time step.
We review the work of many authors on the behavior of the models, looking
particularly at the structure and lengths of their cycles, the sizes of their
basins of attraction, and the flow of information through the systems. In the
limit of infinite N, there is a phase transition between a chaotic and an
ordered phase, with a critical phase in between.
We argue that the behavior of this system depends significantly on the
topology of the network connections. If the elements are placed upon a lattice
with dimension d, the system shows correlations related to the standard
percolation or directed percolation phase transition on such a lattice. On the
other hand, a very different behavior is seen in the Kauffman net in which all
spins are equally likely to be coupled to a given spin. In this situation,
coupling loops are mostly suppressed, and the behavior of the system is much
more like that of a mean field theory.
We also describe possible applications of the models to, for example, genetic
networks, cell differentiation, evolution, democracy in social systems and
neural networks.Comment: 69 pages, 16 figures, Submitted to Springer Applied Mathematical
Sciences Serie
Constitution of an Approximate Equation of Demagnetizing Factors for Cylinder Using Multiple Regression Analysis
An approximate equation is constituted for a cylinder as a function of the aspect ratio of its length to diameter and its normalized axial position. In order to create reference points for the approximate equation, the demagnetizing factor distribution of the cylinder, which has several ratios in a uniform applied field, is computed using a finite element method. From the results of the computations, an approximate equation at an arbitrary Z value along the axial direction of the cylinder is constituted from a multiple regression analysis.ArticleJournal of the Japan Society of Applied Electromagnetics and Mechanics. 17(3):449-452 (2009)journal articl