An application of interpretive structural modelling to analyse preference structure in multiobjective dynamic environmental-economic systems†

This paper applies ISM (interpretive structural modelling) to analyse preference structure in a multiobjective problem of a dynamic environmental-economic model, and terms this method IPSM (interpretive preference structural modelling). Multi-objectives in the model include minimizing social cost of pollution, and maximizing total consumption in a planning interval. IPSM analyses decision-maker's preference relations (mental model) among many Pareto-optimal solutions of the multiobjective systems under the interactive cooperation between the decision-maker and the model-builder, and extracts the decision-maker's preference structure as a hierarchical directed graph, where the vertices of the graph correspond to the Pareto-optimal solutions and the directed edges correspond to the preference relations. An interesting economic interpretation for a preferred solution is discussed in terms of the economic interpretation of the discrete minimum principle.     

Diagnosis Criterion of Abnormality of Transformer Winding by Frequency Response Analysis (FRA)

Frequency response analysis (FRA) is a powerful technique to detect internal abnormalities within power transformers. However, diagnosis criteria of power transformers by FRA have not been fully established yet. In this paper, a new evaluation method of degree of identification between two transfer functions is proposed. In the proposed method, a frequency window is employed and cross‐correlation factor is calculated with moving the window. Furthermore, the proposed method is applied to transfer functions of real transformers with or without some abnormalities. Based on this discussion, objective criteria for diagnosis of abnormalities of transformer windings by FRA are proposed. The proposed criteria are based on a few data of transformers with some abnormalities. Therefore, the proposed criteria are tentative and they would be improved by accumulation of further data.     

Phase Equilibrium in the System CrO2-Cr2O3

The CrO₂-Cr, O₃ equilibrium curve has been determined up to 35 kbars and 1400° C with a piston-cylinder apparatus. The phases were determined by magnetic, X-ray, and microscopic examination. The phase boundary can be represented by a straight line log P versus 1/T plot, where log P = 5.3 - 1400/ T. These results can be extrapolated to agree reasonably well with the results of previous investigations using gas pressure techniques.     

Phase Equilibrium in the System MgO-H2O at High Temperatures and Very High Pressures

Phase equilibrium in the system MgO-H₂O was investigated from 500° to 1450° C at 5 to 40 kbars by a quenching technique using a piston-cylinder apparatus. Brucite decomposed to periclase plus vapor at 810° and 10 kbars, 945° and 20 kbars, 1000° and 32 kbars, and 975°C and 40 kbars. The slope of the decomposition P-T curve became steeper with increasing pressure, infinite at 32^- kbars and 1000C, and then negative above 32 kbars. The extrapolation of this curve to lower pressures agrees well with data of other workers who used hydrothermal techniques.     

A THEORETICAL STUDY ON ADAPTIVE QUALITY CONTROL SYSTEMS

This paper is a study of an adaptive quality control system from a viewpoint of quality goal. The main purpose is to introduce a conceptual framework for setting up quality goals which are in accordance with the external environment and internal capacity of quality control systems. We apply a mathematical general systems approach.

The results of our paper are summarized as follows:

1)As important decision-making in adaptive QCS, the decision-making for estimalion of fitness and examination of attainability are proposed and formalized mathematically.

2)A refinement process is formalized in which models are revised according to the changes of market.

3)Basic steps for setting quality goals are obtained which are based on the above formalization.     

Crystallization of Hexagonal BaNb2O6

Pure hexagonal BaNb₂O₆ crystallizes at 640° to 700°C from an amorphous material prepared by simultaneous hydrolysis of barium and niobium alkoxides. The structure is characterized by layer networks of NbO₆ octahedra. Crystallization isotherms are described by the Avrami equation In (1—f) = -ktⁿ with n=2; the activation energy is 268 kJ-mol-'. Hexagonal BaNb₂O₆ transforms to the ortho-rhombic modification one at 12.50° to 1310°C.     

水栽过滤法去除地表水中氮磷的运行特性及机理

采用水耕植物过滤法(Hydroponic Bio-filter Method,HBFM)净化富营养化地表水的试验表明,在水力负荷为3.0 m3/(m2·d)的条件下,对TN、TP的年均去除率分别为16.8%、30.8%,年均去除速率分别为1.0、0.1g/(m2·d);通过底泥沉积去除的氮、磷分别占系统氮、磷总去除量的62.2%和75.9%,是去除TN、TP的最主要途径.HBFM的最佳水力负荷为3.0～4.0m3/(m2·d).西洋菜剪割强度影响植物的吸收速率,每次剪割长度不得超过10 cm,每月1次的收割频率不影响系统对氮磷的去除效果.     

Semiconducting Bodies in the Family of Barium Titanates

The anomalous resistivity-temperature characteristics found in semiconducting barium titanates were studied in relation to their composition. The resistivity and impedance characteristics and the crystal structures were investigated for different compositions in the systems (Ba, -Sr) (Ti, Sn)O₃, (Ba, Ca, Sr)TiO₃) (Ba, Pb)TiO₃, Ba-(Ti, Zr)O₃, and Ba(Ti, Si)O₃ doped with 0.1 mole % of Ce and also in the system (Ba, Mg, Ce) TiO₃. Bodies whose compositions were quite different from BaTiO₃ could not be semiconducting. The resistivity anomaly in each semiconducting body showed a good correlation with the crystal transition.     

Electrical and mechanical properties of ZrO2(2Y)/TiN composites and laminates made from these materials

High density composites with the compositions of ZrO₂(2Y):TiN=40:60 and 70:30 mol% have been fabricated by hot isostatic pressing for 2 h at 1500°C and 196 MPa. The electrical resistivities (ρ) of the two composites are very different; showing metallic behaviour in the first case and insulating behaviour in the latter case. These properties are highly dependent on the sample texture. Laminated materials with compositions of ZrO₂(2Y)/TiN=(40:60)/(70:30)/(40:60) mol% have been prepared by hot isostatic pressing. The electrical resistivities in the perpendicular and parallel to the interface directions have been determined to be ρ⊥≈1×109 and ρ∥≈ 1×10^-6 Ωm, respectively. A residual stress of as much as ≈ 150 MPa is induced in the interfaces. The fracture toughness is greatly affected by the residual stress. This revised version was published online in November 2006 with corrections to the Cover Date.