Volume 2 : Issue 2, June 2013

Table of Contents, 30 June 2013

Research Title/
Graphical Abstract

Article Information/


Investigation of the Effect of Temperature decreasing on Properties of Metals

Original Research, B5

Mohammadi Ch.

Sci. J. Mech. Ind. Eng., 2(2): 18-22, 2013

ABSTRACT: Before we consider how low temperatures affect the engineering properties 'of specific metals and alloys, we should review the general effects of low temperature upon the properties of metals. As the temperature is lowered, the hardness, yield strength, tensile strength, modulus of elasticity, and fatigue resistance of almost all metals and alloys increase.
Key Words:
Temperature, Metals, Fracture


Study the Preparation Methods and Properties of Ferromagnetic Bronze-Iron Composites

Original Research, B6

Tiro R., Chakin M.

Sci. J. Mech. Ind. Eng., 2(2): 23-25, 2013

ABSTRACT: A combination of powder metallurgy and wire drawing techniques was used to prepare composite materials consisting of fine iron fibers in a 5% Sn bronze matrix. In addition to being ferromagnetic, the materials have excellent mechanical properties and corrosion resistance. Property data are re-ported on alloys containing 2.0, 5.6, 9.9, and 14.3 vol % Fe. The 9.9 vol % Fe alloy, after 99.9% reduction in area, has a coercive force of 320Ω, a remnant induction of 1800 G, and a hysteresis loop squareness, Ir/Is=0.85. The tensile strength of the same alloy is 156000 psi (1077 MN/m2) and its corrosion rate in a solution of 5% NaCI in H20 is not measurably different from the bronze matrix material. The magnetic and mechanical properties are easily controlled by varying the amount of cold working. The magnetic properties attained are within the range of applicability for magnetic recording, and with modest improvements in properties, the alloys could be used in other applications for hard magnetic materials.
Key words:
Ferromagnetic, Bronze, Iron, Composites


The effect of Sulfur and Phosphorus in Low Alloy Steel Welds

Original Research, B7

Chuang L., Woo S.
Sci. J. Mech. Ind. Eng.
, 2(2): 26-28, 2013

ABSTRACT: The purpose of this study was to exchange information on techniques and special apparatus used for measuring weld ability of alloys. Emphasis was on methods, techniques and interpretation of data rather than on specific results. Although solicitation of several techniques was made, all but one of the submissions involved the Gleeble device and this one submission was withdrawn before the time of the session.
Key words:
Sulfur, Phosphorus, Steel, Weld


 The Efficiency Change and the Relationship with Reform Using DEA Model and Malmquist Index

Original Research, B8

Hosseini M H., Hasanpour J., Sazvar A.
Sci. J. Mech. Ind. Eng., 2(2): 29-38, 2013

ABSTRACT: The study uses the technical efficiency and the mathematical model data envelopment analysis (DEA) in an attempt to analyze the performance the Iranian thermal power plant. The DEA is a nonlinear programming technique designed to calculate technical efficiency achieved by decision-making units. Total factor productivity (TFP) change for common set of thermal power plants operating from 2002 to 2008 was examined using a Malmquist productivity index using prowess database. The TFP was divided into efficiency change (caching up phenomena) and technical change (innovations). Improvement in productivity, efficiency change, and technical change was confirmed in Iranian power plants between 2002 and 2008; therefore, the results enable TAVANIR Co. to monitor and spot changes in productivity of its thermal units. In addition, the agents can utilize the result to build their efficiency profile as a function of their competitors. They also can find recommendations for improvement of inefficiency. Given the trend of privatization in Iran’s power generation market, the results confirmed improvement in efficiency and productivity of thermal power plants in the country. Furthermore, a relationship was found between the restructuring and enhancing productivity.
Data envelopment analysis (DEA), Malmquist productivity index, Efficiency changes, reform, Thermal Power Plants