The main goal of the current paper is focused to investigate the effect of isothermal heat treatment

temperature and time on microstructure and strength in a medium carbon vanadium titanium free micro

alloyed steel. Isothermal heat treatment was carried out in the temperature range 350 to 600 C° at

different holding times varying from 2s to 1200s followed by water quenching. Samples were

investigated using optical microscope (OM) and scanning electron microscopy (SEM) paired with

energy dispersive spectroscopy (EDS) and by compressive testing using a servo-hydraulic testing

machine. The results show that, the final microstructure of samples held at high temperatures (550 and

600°C) consists of polygonal intra-granularly nucleated ferrite idiomorphs, combined with grain

boundary ferrite and pearlite were produced and followed by retained austenite that transformed to

martensite upon quenching (incomplete transformation phenomenon). At intermediate temperatures

(450 and 500 °C) an interlocked acicular ferrite (AF) microstructure is produced, hence acicular ferrite

becomes prevalent in the microstructure at (450 °C). The microstructure after the heat treatment at

500°C consists coarse nonpolygonal ferrite grains separated by pearlite colonies. However, at low

temperatures (400 and 350°C), the final microstructure of the samples held at 350°C consists of

bainitic sheaves, where the sheave of parallel acicular ferrite plates, similar to bainitic sheaves but

intra-granularly nucleated were observed, which called in some references as sheaf type acicular ferrite

for samples isothermally treated at 400°C. Yield stress was determined by compression testing on samples

with final Microstructure, the results show that, the observed change in the microstructure is related by a

marked decrease of compressive yield strength, approximately from 1000 to 700 MPa.

For Arabic letters recognition, we achieve three of pattern recognition approaches namely gray level co-occurrence matrix (GLCM), local binary pattern recognition (LBP) and artificial neural network (ANN) and compare between them to result best performance. Two of these methods level co-occurrence matrix and local binary pattern recognition are used for feature extraction whereas in artificial neural network (ANN) we use the intensity values of pixels for input of the neural network. Two classifiers are used, the K-Nearest Neighbor classifier (KNN) for the LBP, GLCM and neural network classifier for (ANN) artificial neural network. Also, we evaluate the results by using leave one person out approach, fold classification and leave one out.

this paper derives extended three-stage recursive identification algorithm of MISO for (CARARMA) systems. Based on The decomposition technique, four subsystems are obtained and the parameters of each subsystem are identified. Some model validation methods are computed to measure the model value and Akaike’s Final Prediction Error Criterion (FPE) is used to verify the selection of system order. The algorithm has a high computational efficiency because the covariance matrices dimensions become small in each subsystem. Finally, this algorithm effectiveness is demonstrated in simulation example.

Jamal Abdul-Nasser is a major trunk road that divides Sebha city into two semi-equal parts. It connects almost all districts with different activities and services in the center of the city. Alongside Jamal Abdul-Nasser Street, exist various types of activities: administrative, educational, commercial, public services and some other activities. Due to its importance, the street carries out the densest traffic movement within the city. This paper tries to study and analyze traffic movement at five intersections on Jamal Abdul-Nasser Street: (1) Al-Nahdha; (2) Khaled IbnAl-Walid; (3) Al-Khotoot; (4) Al-Tijari Bank; (5) Al-Zeraie Bank. Selection of the pre-mentioned intersections referred to their importance as converging points to various important activities and land uses. Data required for the study purposes include intersection characteristics, traffic flow characteristics and traffic composition pattern. The results reveal the significance of taking care of the geometric and regulatory aspects that enable the intersections to perform well with regard the smoothness of traffic flow.

Isothermal transformation characteristics of a medium carbon Ti-V microalloyed steel were

investigated using light microscopy, scanning electron microscopy (SEM) equipped with energy

dispersive spectroscopy (EDS), and by uniaxial compressive testing. Samples austenitized on 1100 C

were isothermally treated in the range from 350 to 600 C and subsequently water quenched. The

final microstructure of the samples held at 350 C consisted of bainitic sheaves and had compressive

yield strength, approximately from 1000 MPa, which is attributed to high dislocation density of

low bainite. At 400 and 450 C, acicular ferrite became prevalent in the microstructure. It was also

formed by a displacive mechanism, but the dislocation density was lower, leading to a decrease of

compressive yield strength to approximately 700 MPa. The microstructure after the heat treatment at

500 C consisted of coarse non-polygonal ferrite grains separated by pearlite colonies, principally

dislocation free grains, so that the compressive YS reached a minimum value of about 700 MPa. The

microstructure of the samples heat-treated at 550 and 600 C consisted of pearlite and both grain

boundary and intragranular ferrite, alongside with some martensite. After 600 s, austenite became

stable and transformed to martensite after water quenching. Therefore, the presence of martensite

increased the compressive YS to approx. 800 MPa.

This work is focused on nucleation stages during isothermal austenite decomposition in two medium carbon Vanadium Ti / Ti free micro alloyed steels. Isothermal treatment was carried out in the temperature range 350 to 600οC. Metallographic evaluation using optical and scanning electron microscopy (SEM) enabled determination of the nucleation onset phases of isothermally decomposed austenite. Mainly three phases are found to be relevant to this initiation stage of transformation: first is related to grain boundary nucleated ferrite (GBF), second is related to intra-granularly nucleated ferrite (IGF) and the third to pearlite (P). GBF and IGF are divided into the high temperature and the low temperature segments as consequence of either displacive or diffusion nature of transformation. Addition of titanium to V – micro alloyed steel in this work seems to be balanced by a slightly higher C and Mn content, leading to limited effect on nucleation stage of austenite decomposition. The results show that during continuous cooling, onset of pearlite phase can take place. It occurs at temperatures ≥ 500 C°, followed by an incomplete reaction phenomenon. The main characteristics of pearlite is always nucleated on the surface between proeutectoid ferrite and austenite. Incubation time for onset of pearlite decrease with decrease of temperature.