摘要:

The safety of structures is described and estimated by the probability of failure of the structures. The optimum structure is defined as the structure consisting of members possessing approximately equal values of the probability of failure. A computer program which can calculate, iteratively, the probability of failure of the individual members as well as of the whole structure for the spaced frame structure is generated herein. The weakest link model is assumed to be available both for statically determinate and statically indeterminate structures. The dead load, seismic load and the strength of material are considered to be log‐normally distributed random variables. By changing the cross‐sectional area of the members, the probability of failure of individual members can be kept to a certain pre‐decided value, for example, 10–5. An example of the design of a space frame is presented. All the wide‐flange cross sections are selected from the AISC design manual.

ISSN:0253-3839    

DOI:10.1080/02533839.1984.9676757

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

ISSN:0253-3839    

DOI:10.1080/02533839.1984.9676758

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Acidic ferric ion, an effective and important oxidizing agent for mineral leaching, is usually produced by direct dissolution of the corresponding salts into the solution or can be prepared in‐situ or in separate aerated batch reactors by chemical oxidation of iron sulfide through a number of different processes. The purpose of this paper is to present the idea and the results of generating the useful ferric leaching medium by bacterial oxidation of pyrite under the commercial leaching conditions in an underground copper mine. The information presented deals mainly with factors promoting the continuous oxidation of pyrite by iron‐oxidizing bacteria and the related factors influencing the extraction of copper from the enargite. This is the first attempt to produce a ferric leaching medium in an underground mine by a microbiological process. The generation technology and engineering layout are also discussed.

ISSN:0253-3839    

DOI:10.1080/02533839.1984.9676759

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The characteristics of crystallization in a batch Couette flow crystallizer are modeled by population balance, mass and energy equations. The effective and powerful method of Legendre polynomials is employed to transform the partial differential equation of population balance into a series of ordinary differential equations of Legendre series expansion coefficients. Optimization theory is applied to find the minimum coefficient of variations, which accounts for the uniformity of crystal‐size distribution within the crystallizer. The results are obtained by the Runge‐Kutta‐Gill computational method and are explained by the physical significance of the growth and nucleation phenomena.

ISSN:0253-3839    

DOI:10.1080/02533839.1984.9676760

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Al‐7 w/o Ni alloys were unidirectionally solidified at different solidification rates (R) and thermal gradients (GL). Al3Ni whisker morphology is discussed in terms of solidification parameters and also correlated with alloy strength. For a given thermal gradient (GL=17°C/cm), low solidification rates give rise to large whisker spacing (λ) and size (d), maintaining the constant value ofλ/dbetween 2.0 and 2.3. Interrupted growth of Al3Ni whiskers along the solidification direction causes a reduction inλ/das compared with that for continuous whiskers (λ/d=2.8). Tensile strength for continuous fiber strengthened composites is calculated to be 33.6 kg/mm2, whereas the experimental value ranges from 18 to 19 kg/mm2. A considereable decrease in strength is attributed to theGL/Rbeing much smaller (10°C.hr/cm2) than the theoretical value (300°C.hr/cm2). Longer Al3Ni whiskers due to lower solidification rates can be explained by the interface precipitation model proposed by Honeycombe and Davenport.

ISSN:0253-3839    

DOI:10.1080/02533839.1984.9676761

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

ISSN:0253-3839    

DOI:10.1080/02533839.1984.9676762

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

A microprocessor‐based electrohydraulic servo system has been constructed and tested. It is implemented with an 8‐bit single‐chip microcomputer to control a hydraulic motor. The control algorithm is based on variable structure control principles. The experimental results show that the system is under good control and possesses a great potential for electrohydraulic servo control.

ISSN:0253-3839    

DOI:10.1080/02533839.1984.9676763

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

ISSN:0253-3839    

DOI:10.1080/02533839.1984.9676764

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

A computational algorithm is proposed for catalyst pellets or reactors experiencing concentration‐dependent deactivation. In the integration of the deactivation equation in each time interval, the concentration of poison, reactant or/and product is considered to be a constant. The value of concentration is recalculated from the mass balance equation before integrating the deactivation equation. By such an approach, the number of equations is reduced; thus a two‐dimensional problem can be converted to a single‐dimensional one.

ISSN:0253-3839    

DOI:10.1080/02533839.1984.9676765

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

ISSN:0253-3839    

DOI:10.1080/02533839.1984.9676756

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor