- TITLE:
MODELLING, RESEARCH AND OPTIMIZATION OF CARBIDIC AUSTEMPERED DUCTILE IRON DURING ABRASION AND DRY FRICTION
- AUTHOR(S):
V. Todorov, G. V. Duncheva, M. Atanasova, G. Rashev
- ABSTRACT:
This article presents the outcomes from experimental investigation of the wear resistance of specimens made of carbidic austempered ductile iron (CADI) which are isothermally hardened in the fields of upper and lower bainite. The specimens are subjected of abrasive wear and dry friction. A mathematical modeling of the experimental results has been carried out. A regression analysis and analysis of variance (ANOVA) have been fulfiled using QStatLab package. On the basic of the regression models obtained, three single-purpose optimization tasks have been solved in order to determined the maximum wear resistance of CADI.
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MODELLING, RESEARCH AND OPTIMIZATION OF CARBIDIC AUSTEMPERED DUCTILE IRON DURING ABRASION AND DRY FRICTION
- TITLE:
MODELLING, RESEARCH AND OPTIMIZATION OF MECHANICAL PROPERTIES OF CARBIDIC AUSTEMPERED DUCTILE IRON
- AUTHOR(S):
G. V. Duncheva, V. Todorov, M. Atanasova, G. Rashev
- ABSTRACT:
An object of this study is the effect of the carbide phase quantity and austempering temperature on the mechanical properties of samples made of carbidic austempered ductile iron (CADI). Analysis of variance and regression analysis have been carried out on the basis of experimental data obtained. On the basis of regression models obtained, three multi- objective optimization tasks have been set out solved.
Thus, the optimal values of liquid carbide phase and austempering temperature of CADI have been established.
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MODELLING, RESEARCH AND OPTIMIZATION OF MECHANICAL PROPERTIES OF CARBIDIC AUSTEMPERED DUCTILE IRON
- TITLE:
PERFORMANCE EVALUATION OF WIRE COIL INSERTS IN TURBULENT TUBE FLOW – CRITICAL REVIEW
- AUTHOR(S):
P. Bonev, V. M. Petkov
- ABSTRACT:
There are different kinds of inserts employed in the heat exchanger tubes such as helical/twisted tapes, coil wires, ribs/fins/baffles, and winglets. This paper presents performance evaluation of some wire coil inserts, using a simple evaluation criterion to assess the possible energy benefit. Wire coil inserts, classical and modified, with different geometrical parameters in the ranges: / 0.06 0.12e D , / 1.8 33.0p e , with working fluids as air or water in the range 5 Re (0.4 1.2) 10 have been taken into consideration.
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PERFORMANCE EVALUATION OF WIRE COIL INSERTS IN TURBULENT TUBE FLOW – CRITICAL REVIEW
- TITLE:
BALANCING THE INERTIA FORCES OF SINGLE CYLINDER HYPOCYCLOIDAL RECIPROCATING MACHINES
- AUTHOR(S):
V. Enchev
- ABSTRACT:
The purpose of this article is to determine the inertia forces of reciprocating moving masses of single cylinder hypocycloidal reciprocating machines and to present opportunities for their balance. Balancing of the rotating masses in the mechanism is possible by known methods with counterweights. Unbalanced inertia force of reciprocating moving masses of the piston and the point mass of the rod remains. This force can’t be ignored in high-speed compressors. On the other hand it is significant difficulty to balance this force and
requires deeper study to find ways to eliminate or limit its impact.
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BALANCING THE INERTIA FORCES OF SINGLE CYLINDER HYPOCYCLOIDAL RECIPROCATING MACHINES
- TITLE:
STIFFNESS FACTOR FORMATION UNDER STRUCTURAL CIRCUIT SYNTHESIS OF INDUSTRIAL ROBOTS WIRE-FRAME ARRANGEMENTS
- AUTHOR(S):
Alrefo Ibrahim F.S.
- ABSTRACT:
It is suggested that the best solutions during the structural circuit synthesis of wireframe arrangements for industrial robots with and without the mechanisms of parallel structure are chosen on account of the integrated stiffness index based on the relative stiffness factor (where the round rod of the same cross section and length is taken as a rating criterion) and stiffness instability factor within a manipulated object travelling area.
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STIFFNESS FACTOR FORMATION UNDER STRUCTURAL CIRCUIT SYNTHESIS OF INDUSTRIAL ROBOTS WIRE-FRAME ARRANGEMENTS
