Activation energy for static recrystallization estimated in this work of 281kJ/mol is in excellent agreement with previously reported data (both experimental and mdeled) and indicates that difusion of Nb in austenite is most probably the rate controlling process

The influence of vanadium and nitrogen on microstructure and mechanical properties of medium-carbon

steels has been studied by means of metallography and mechanical testing. Vanadium addition to the low

nitrogen steel suppresses the formation of ferrite–pearlite following the low reheating temperatures and microstructure

consists of bainitic sheaves. Increasing nitrogen at the same vanadium level promotes the acicular

ferrite formation. For high reheating temperatures, dominantly acicular ferrite structure in both the low

nitrogen and the high nitrogen vanadium steels is obtained. The results suggest that vanadium in solid solution

promotes the formation of bainite. The effect of nitrogen is related to the precipitation of VN particles in

austenite with high potency for intragranular nucleation of acicular ferrite and to the precipitation of V(C, N)

particles in ferrite with high potency for precipitation strengthening. Addition of both vanadium and nitrogen

considerably increases the strength level, while CVN20 impact energy increases on changing the microstructure

from bainitic ferrite to the fine ferrite–pearlite and acicular ferrite.

The rapid growth of advanced robots has given researchers unprecedented opportunities to explore and discover new fields of research where robots can be used to assist humans in their daily life. There are many applications that use robots and automation in different aspects of life such as industry, medical, domestic machines and etc. In this paper, the work has been devoted for the use of robotics and robots in cleaning process. The window cleaning robot is one of the robots that have emerged in recent decay. This robot can be used in homes, offices and large buildings. The main target is to design a robot that can clean glass windows efficiently and rapidly even in dangerous and hazardous places. The robot will be controlled using the Programmable Logic Controller PLC. The motion will generated by three servo motors.

The influence of vanadium and nitrogen on microstructure and mechanical properties of

medium-carbon steels has been studied by means of metallography and mechanical testing.

Vanadium addition to the low nitrogen steel suppresses the formation of ferrite-pearlite following

the low reheating temperatures and microstructure consists of bainitic sheaves. Increasing nitrogen

at the same vanadium level promotes the acicular ferrite formation. For high reheating temperatures,

dominantly acicular ferrite structure in both the low nitrogen and the high nitrogen vanadium steels

is obtained. The results suggest that vanadium in solid solution promotes the formation of bainite,

whereas the effect of nitrogen is related to the precipitation of VN particles in austenite with high

potency for intragranular nucleation of acicular ferrite and to the precipitation of V(C,N) particles in

ferrite with high potency for precipitation strengthening. Addition of both vanadium and nitrogen

considerably increases the strength level, while CVN20 impact energy increases on changing the

microstructure from bainitic ferrite to the fine ferrite-pearlite and acicular ferrite.

The induction motor is the most common driver in industry and has been previously proposed as a means of inferring the condition of an entire equipment train, predominantly through the measurement and processing of power supply parameters. This has obvious advantages in terms of being non-intrusive or remote, less costly to apply and improved safety. This paper describes the use of the induction motor current to identify and quantify a number of common faults seeded on a two-stage reciprocating compressor. An analysis of the compressor working cycle leads to current signal the components that are sensitive to the common faults seeded to compressor system, and second- and third-order signal processing tools are used to analyse the current signals. It is shown that the developed diagnostic features: the bispectral peak value from the amplitude modulation bispectrum and the kurtosis from the current gives rise to reliable fault classification results. The low feature values can differentiate the belt looseness from other fault cases and valve leakage and inter-cooler leakage can be separated easily using two linear classifiers. This work provides a novel approach to the analysis stator current data for the diagnosis of motor drive faults

Adaptive control systems have been studied for many years. There are many types of adaptive control algorithms, one of which is the reference model technique. In this paper, the work has been devoted for the use of model reference adaptive control system (MRAC). The MRAC algorithm with parameters adaptation was developed and applied for control of the DC motor drive. The algorithm is based on the gradient technique with parameter adaptation. The controller can significantly improve system behavior and force the system to follow the reference model and minimize the error between the model and plant output.

In this paper a data compression technique using double transforms is proposed. The compression ability of any transform or a combination of transforms is evaluated by the error in the reconstructed data and/or its fast implementation. This investigation concerns the reduction in the computational requirements for data compression without increasing, significantly, the error in reconstruction. The double transform approach is based on the transformation of input data using WHT, rejecting some of the spectral components, converting the spectrum from WHT domain into DCT domain, and then inverse transform using DCT. In the experimental part of this paper, several contours extracted from 2D images, using the FCCE method for contour extraction, ware used. It is shown that the proposed technique reduces the number of multiplication operations, comparing with DCT. In addition, the compression process does not require any multiplications at the transmitting end, thus can be used for real time compression applications.

Experiments were performed to investigate the diffusion ignition process that occurs when hot inert gas (Argon or Nitrogen) is injected into the stoichiometric propane-oxygen mixture at the test section. Detonation wave initiated by spark plug in the driver section in stoichiometric acetylene-oxygen mixture at P = 0.5 bar and room temperature, propagates as incident shock wave in the driven section through inert gas after bursting the diaphragm separating the sections. At the end of driver section the inert gas is heated behind the reflected shock wave and then injected into the test section with the stoichiometric propane-oxygen mixture through the hole of 8 or 11.2 mm in diameter. The results of experiments indicate that ignition occurs when the static enthalpy of injected mass of inert gas exceeds some critical value. The induction time and the adiabatic temperature after reaction of mixed inert gas and Propane-oxygen mixture were determined with the use of CHEMKIN II software [1] for different values of mixing volume ratio.

A definition of thermophysiological parameters of the Specific Anthropomorphic Mannequin (SAM) CAD model material is proposed in this paper to calculate the temperaturerise in the head of cellular handset users. The SAM materials have the electrical and thermal parameters based on the averaged properties of a heterogeneous High-Resolution European Female Head (HR-EFH) with twenty five different tissues. The specific absorption rate (SAR) and the temperature-rise in the SAM because of the exposure to radiation of different handset models, i.e., candy-bar with external antenna and candy-bar with internal antenna, are calculated in the GSM900 and GSM1800 using a FDTD-based platform. The computations were also carried out applying HR-EFH for comparison.

A thorough investigation into the effect of the hand-hold position on the electromagnetic (EM) wave interaction of a clamshell-type cellular handset and a human is presented in this paper. A FDTD-based platform, SEMCAD-X, is used to achieve the simulations, where two semi-realistic handset models of different external-antenna attachment positions (left and rightside) are designed with the most parts configuration and operating at different GSM-frequency standards (GSM-900, GSM-1800/DCS, and UMTS/IMT-2000). Moreover, homogeneous and heterogeneous CAD models are used to simulate the user’s head, whereas, a homogeneous model with three different tissues is designed to simulate the user’s hand-hold. The antenna performance, as well as, the specific absorption rate (SAR) in tissues are both examined for different (42) possible cases, where several antenna/hand positions are considered in simulation.