ORIGINAL_ARTICLE
Determination of Permeability of Concrete to Chloride Ions by Rapid Test Procedures
Methods which can be used to assess the chloride permeability of various types of concrete in a relatively short time are described. An electrical potential from 60-80 volt DC is applied either between a chloride solution ponded on a slab surface and the top of rebar mat, or between two faces at a core taken from a structure. The amount of chloride and sum of the electrical current which passes through the specimen during the test period are used to predict the permeability of the concrete. Results compare favorably with values determined in long-term ponding on similar concretes.
https://www.ije.ir/article_71085_c754979464987af7129bc27242994e97.pdf
1993-11-01
125
132
corrosion
Concrete
Chloride
Diffusion
Permeability
Electrical Potential
R.
Dehghanian
dehghani@cc.iut.ac.ir
1
Elecrtical and Computer Enginnering, Isfahan University of Technology
AUTHOR
ORIGINAL_ARTICLE
A Self-Consistent Technique for the Construction and Evaluation of the Three-Parameter Corresponding States Principles
A self-consistent approach for the evaluation of the existing three-parameter corresponding states principles of non-polar fluids and the calculation of the corresponding states parameters is presented. This self consistent approach is based upon the assumption that the contribution of the third parameter to the thermophysical properties is much smaller than the contributions of the first two parameters which are generally the molecular energy and length parameters, e/k and s. Based on this self- consistent approach several existing three-parameter corresponding states principles of non-polar fluids are evaluated. It is shown that the three-parameter corresponding states principle based on the two-and three-body intermolecular potential parameters effectively satisfies the requirements of the present selfconsistent technique. The corresponding states principle parameters of normal hydrocarbons are calculated through the present technique and they are reported here.
https://www.ije.ir/article_71086_ee28c2772d71782b4a0ded6695697d58.pdf
1993-11-01
133
146
self
Consistent Technique
Three
Parameter Corresponding States Principles
Lennard Jones (n
m)
Triple Interaction
Reduced Temperature and Pressure
potential function
M.
Edalat
medalat@ut.ac.ir
1
Chemical & Petroleum Engineering, University of Tehran
AUTHOR
ORIGINAL_ARTICLE
Taxonomy of Global Air Transport
Data from the United Nations and the International Civil Aviation Organization Information Systems were used as a base for characterizing, classifying and comparing air transport demand and supply features of 156 countries. Relevant data from 1980 were chosen to reflect five sets of characteristics namely, air transport, 50cm-economic status, population demography, geographical and environmental features, and political features. The resulting 123 variables were assessed for accuracy and reliability and subjected to correlation and factor analysis to screen and identify key characteristics reflecting air transport potentials. This led to a suitable basis for grouping countries to allow peer comparison based on composite indices. The resulting homogeneous clusters of countries provided a better than heretofore available framework for the evaluation of differences and similarities between national consumption and supply of air transport services. Regression models were developed for each peer group of countries to evaluate air transport potential, allowing a basis for more confidence in economy-of-scale decisions.
https://www.ije.ir/article_71087_9e6398e5cfb4f1e83b79ac4f1a769140.pdf
1993-11-01
147
158
Air transport
peer groups
regression analysis
Aviation System
M.
Vaziri
manouchehrvaziri@yahoo.com
1
Civil Engineering, Sharif University of Technology
AUTHOR
ORIGINAL_ARTICLE
A General Boundary-Integral Formulation for Zoned Three-Dimensional Media
A new boundary-integral formulation is proposed to analyze the heat transfer in zoned three-dimensional geometries. The proposed formulation couples the boundary formula, the gradient of the boundary formula, and the exterior formula. An advantage of this formulation over the traditional methods is that any linear condition at the interface between subdomains may be incorporated into the formulation at the outset. In addition, the new method provides a sparse and well-conditioned matrix of coefficients with a minimum number of equations.
https://www.ije.ir/article_71088_2ece7576bb7630b80a45bfbf48036675.pdf
1993-11-01
159
168
Boundary
Integral
Exterior formula
Three
Dimensional Media
heat transfer
M.
Rezayat
hasnomail@ije.ir
1
Structural Dynamics Research Corporation, Milford, Ohio, USA
AUTHOR
ORIGINAL_ARTICLE
On the Displacement-Stress Continuous Finite Elements
For the analysis of composite media, three different compatible and mixed finite element formulations are presented which apriori enforce the continuity of stresses as well as displacements at the element interfaces. The formulations are applied for the analysis of hi-material interfaces in two problems often encountered in the field of orthopaedic biomechanics, that is the fixation analysis in the cemented tibial implants and that in the push-out tests with attached interface. The results reveal that, in contrast to the conventional displacement-based finite element method which yields very significant stress discontinuities, the new techniques predict interface stresses that are both continuous and accurate.
https://www.ije.ir/article_71089_7088cf07f19e3ab8d182698b5fed314f.pdf
1993-11-01
169
178
Finite elements
interface
Bi
Material
Stress
Continuity
constraints
A.
Shirazi-Adl
hasnomail@ije.ir
1
Mechanical Engineering, Ecole Polytechnique Fédérale de Lausanne
AUTHOR
ORIGINAL_ARTICLE
Reinforced Concrete Columns in Torsion (RESEARCH NOTE).
ACT does not suggest any regulations for columns under torsion. However, by all means, the number of such columns used in steel and concrete structures is abundant. In this paper, using the results of laboratory tests on 35 square and rectangular columns with intermediate slender ratios, relations for determination of torsional strengths of reinforced concrete under axial compression have been developed. Compatibility of this relation with laboratory results has been examined.
https://www.ije.ir/article_71090_3f14a0ab444e0216a3bab7cd2799562e.pdf
1993-11-01
179
185
reinforced concrete
Columns
Torsion
S.
Daniali
hasnomail@ije.ir
1
Civil Engineering, Lamar University of Beaumont
AUTHOR
F.
Irani
irani_fe@yahoo.com
2
Civil Engineering, Ferdowsi University of Mashhad
AUTHOR