Influence of cold-rolling reduction on retained austenite texture in cold-rolled and intercritically annealed TRIP-assisted steel

The newly developed multiphase transformation-induced plasticity (TRIP) steels are of interest for industrial applications because of their excellent combination of high strength and ductility. Their performance can be successfully controlled by designing an optimum balance in the volume fractions of ferrite, bainite and retained austenite. The characteristics of the retained austenite are considered to be the main key to achieving the desired final properties. Against this background, the effects of retained austenite characteristics, such as volume fraction, carbon concentration, size and shape, on the behaviour of TRIP steels have been studied. The crystallographic orientation of the retained austenite was measured by electron backscattered diffraction (EBSD). The effect of initial cold-rolling reduction on the microtexture development of the retained austenite was studied on an aluminium-containing TRIP steel. The results show that, by increasing the cold-rolling reduction before the final austempering, the main components of the face-centred cubic phase, i.e. copper, brass and Goss, dominate the texture of the retained austenite. In contrast, the copper and Goss components of the retained austenite are absent in the texture of lightly deformed sheets. The features of the preferred orientation of the retained austenite are discussed and explained in terms of the annealing texture of the recrystallized ferrite and bainite

Finite-Temperature Properties of Ba(Zr,Ti)O3_3 Relaxors From First Principles

A first-principles-based technique is developed to investigate properties of Ba(Zr,Ti)O$_3$ relaxor ferroelectrics as a function of temperature. The use of this scheme provides answers to important, unresolved and/or controversial questions, such as: what do the different critical temperatures usually found in relaxors correspond to? Do polar nanoregions really exist in relaxors? If yes, do they only form inside chemically-ordered regions? Is it necessary that antiferroelectricity develops in order for the relaxor behavior to occur? Are random fields and random strains really the mechanisms responsible for relaxor behavior? If not, what are these mechanisms? These {\it ab-initio-based} calculations also leads to a deep microscopic insight into relaxors.Comment: 3 figures + Supplemen

Benthic invertebrates in the shrimp ponds in Tiab area

In order to study the quantity and quality evaluation of benthic invertebrates in shrimp ponds belonging to Persian Prawn Co., in Tiab area (Hormozgan province), sampling of sediments were carried out every other 14 days, from August 18 to October 27, 1998, during the period of shrimp culture. Sediments were sampled from three different point of 9 ponds by grab (Van Veen 0.02 m^2) for identification macrofauna, meiofauna, grain size and measurement of total organic matter. Macrofauna benthic were few and were found only in three ponds. Three groups of meiofauna including: Nematoda, Naplius and copepoda were distinguished. Their abundance was increased during main shrimp culturing period and was decreased at the end of it. Silt was the main part of soil in most ponds

Investigating the potential for using a simple water reaction turbine for power production from low head hydro resources

In this analysis the simple reaction water turbine known as Barker’s Mill is revisited. The major geometrical and operational parameters have been identified and, using principles of conservation of mass, momentum and energy, the governing equations have been developed for the ideal case of there being no frictional losses. The solutions of the resulting equations are offered in a non-dimensional form. It is shown that the maximum torque produced by the machine is developed when the turbine is stationary. At this point the net output power is zero. As the load torque is decreased the turbine rotates and power is produced. Furthermore, because of a centrifugal pumping effect, the mass flow rate of water through the turbine increases during acceleration. Further decrease in the load torque is accompanied by increases of speed, output power, water mass flow rate and efficiency. It is shown that when the load torque is reduced towards half the value of the torque at the stationary condition, water mass flow rate, rotational speed and output power tend towards infinity. Under this condition the efficiency of the machine approaches unity. The non-dimensional characteristics of the idealized turbine are used to investigate the general characteristics of the machine and to explore its application for production of power from water reservoirs with low heads. Theoretical analysis of a simple reaction turbine is presented including consideration of the fluid frictional losses for a practical situation. A practical turbine will never run away towards infinite speed and the maximum power and efficiency of such a turbine will depend on the fluid frictional losses. Here a new factor is defined, representing the overall fluid frictional losses within the turbine. Finally this paper presents briefly the experimental performance results for two simple reaction water turbine prototypes. The two turbine prototypes under investigation have rotor diameters Ø0.24 m and Ø0.12 m respectively. The two turbine models were tested under supply heads ranging from 1 m to 4 m. The simple reaction water turbine can operate under very low hydro-static head with high energy conversion efficiency. This type of turbine exhibits prominent self-pumping ability at high rotational speeds. Under low head to achieve high rotational speeds the turbine diameter should be very small and this limits the volumetric capacity and hence the power generation capacity of such a turbine. Consequently the practical applications of this turbine would be limited to micro-hydro power generation. The split pipe design of the reaction turbine tested is easy to manufacture and it has been shown to have overall energy conversion efficiency of approximately 50% even under low heads

Investigate the potential of using trilateral flash cycle for combined desalination and power generation integrated with salinity gradient solar ponds

This paper examines the concept of using the trilateral flash cycle for combined desalination and power generation from salinity gradient solar ponds in the salt affected areas of Australia. Firstly causes of the high salinity in the ground waters of northern Victoria, Australia are discussed. Existing salinity mitigation schemes are introduced and the integration of solar ponds with those schemes is discussed. Further the basic working principle of the combined desalination and power generation system is discussed followed by discussion of the governing equation and thermodynamics used in the desalination and power generation process. Experimental setup and the test results are briefly explained to give an idea of the performance of the present system. Later it is shown how a combined desalination and power generation system can be coupled with a solar pond for fresh water production and power generation. Following the introduction of this concept the preliminary design is presented for a demonstration of a combined desalination and power plant coupled with a solar pond of 10000 m2 surface area and a depth of 3 m located in the northern region of Victoria. The performance, including fresh water output, power output and efficiency of the proposed plant operating in northern Victoria is analysed and the results are discussed

Modeling of Individual and Organizational Factors Affecting Traumatic Occupational Injuries Based on the Structural Equation Modeling: A Case Study in Large Construction Industries

Background: Individual and organizational factors are the factors influencing traumatic occupational injuries. Objectives: The aim of the present study was the short path analysis of the severity of occupational injuries based on individual and organizational factors. Materials and Methods: The present cross-sectional analytical study was implemented on traumatic occupational injuries within a ten-year timeframe in 13 large Iranian construction industries. Modeling and data analysis were done using the structural equation modeling (SEM) approach and the IBM SPSS AMOS statistical software version 22.0, respectively. Results: The mean age and working experience of the injured workers were 28.03 ± 5.33 and 4.53 ± 3.82 years, respectively. The portions of construction and installation activities of traumatic occupational injuries were 64.4% and 18.1%, respectively. The SEM findings showed that the individual, organizational and accident type factors significantly were considered as effective factors on occupational injuries’ severity (P < 0.05). Conclusions: Path analysis of occupational injuries based on the SEM reveals that individual and organizational factors and their indicator variables are very influential on the severity of traumatic occupational injuries. So, these should be considered to reduce occupational accidents’ severity in large construction industries