The demand for economical steels has increased over past years. Steels are expected to have as lean chemistry as

possible and to be easier to fabricate. At the same time they are expected to have properties at least equal to steels which

are being substituted. These demands have been, at least in part, met by V microalloyed medium carbon forging steels

in order to substitute traditional quenched and tempered (Q+T) steels. In spite of some lower toughness, V microalloyed

medium carbon forging steels broaden its application due to considerable energy save by eliminating the heat treatment

from the production route. During continuous cooling, dominantly acicular ferrite microstructure is formed. Main

characteristics of acicular ferrite are intragranular nucleation and strongly disorganized microstructure with a larger

ability to deflect cracks. Acicular ferrite is, therefore, widely recognized to be a desirable microstructure due to good

mechanical properties [5]. On the other hand, generally, data related to isothermal decomposition seems to be lacking.

Therefore, the aim of the present study is to clarify the influence of transformation temperature and time on austenite

isothermal decomposition in V-microalloyed forging steels.

The role of technology is becoming more and more important in the different aspects of our life, and its role in ELT is no exception. An example of the application of technology in ELT is email, which is considered one of the most effective tools of communication nowadays. The paper investigates the application of email in thesis supervision in Libya taking the Department of English at the University of Zawia and its counterpart in the School of Languages at the Libyan Academy as examples. The aim is to shed light on the situation and determine to what extent Libyan supervisors and supervisees benefit from email as one of the modern technological tools in facilitating their work. Another aim is to try to specify the problems they face in this respect in order to find better ways that may help in dealing with them. To fulfill these aims, two questionnaires were designed; one for supervisors and the other for supervisees. These questionnaires sought answers to the main research question: To what extent do supervisors and supervisees use email in their communication with each other and for what purpose. The results show that half of the participating supervisors do not use email in their supervision. Similarly, half of the supervisees investigated were found not to be using email to communicate with their supervisors mainly because their supervisors were not willing to use it. One of the possible reasons for not using email by supervisors is that they are technophobes because they lack knowledge and experience in using technology and thus they are not aware of its importance and usefulness amongst other reasons 

In this study, the production of ethylene and hydrogen is studied via the thermal cracking of ethylene in an ethylene plant based in Libya. During the process of thermal cracking, a mix of naphtha and steam is input into tubes that are directed to the naphtha main line. The utilization of steam is generally used because of the partial removal of coke which has undesirable effects on the process. The coke accumulation on the coils, or tubes, result in a decrease in pressure and also reduction in the yields produced. In this work, the naphtha thermal cracking process is both designed and solved numerically. A thorough comparison of the design results and the data extracted from the experiment reveal that the design may predict the overall process precisely. Also, the direct effects of CO2 are studied with regard to the accumulation of coke. Based on the results of two separate scenarios, the process of thermal cracking with the CO2 is beneficial to the overall process due to the higher yield of ethylene and propylene, and less accumulation of coke, and, in turn, less thickness on the coils inside the furnace. The results from the simulation show that the run time, or run length, of the furnace with the addition of CO2 becomes almost two times as the run time with adding steam. Based on these results, this study has proven to be worthy to explore, and the addition of CO2 has been observed to have noticeably positive results on the thermal cracking process.

This paper presents an application of a condition-monitoring system (CMS) based on a polynomial regression model (PRM) to study the influence of heat loss on a wind generator’s temperatures. Monitoring the wind generator temperatures is a significant for efficient operation, and plays a key role in an effective CMS. Many techniques, including prediction models can be utilized to reliably forecast a wind generator’s temperature during operation and avoid the occurrence of a failure. PRMs are widely used in situations when the relationship between the response and the independent variables are curve-linear. These techniques can be used to construct a normal behavior model of an electrical generator’s temperatures based on recorded data. Many independent variables affect a generator’s temperature; however, the degree of influence of each independent variable on the response is dissimilar. In many situations, adding a new independent variable to the model may cause unsatisfactory results ;therefore, the selection of the variables should be very accurate. A generator’s heat loss can be considered a significant independent variable that greatly influences the wind generator with respect to the other variables. A generator’s heat loss can be estimated in intervals by analyzing the exchange in the heat between the hot and cold fluid through the heat exchangers of wind generators. A case study built on data collected from actual measurements demonstrates the adequacy of the proposed model. 

Abstract

Fuel flexibility will drive the energy demand in the near future. The use of different syngas compositions from various sources will play a major role in the global fuel mix. CO2 in the blends will also be added as a mechanism to improve carbon capture and storage technologies. However, this can trigger instabilities such as thermoacoustics, flashback, autoignition and blowoff. In terms of blowoff, the phenomenon is still not entirely understood. This project presents a series of experiments to determine the behaviour and impact on the blowoff process at various swirl numbers, nozzle geometries and gas compositions. The Central Recirculation Zone was analyzed just before blowoff. The results show how the strength and size of the recirculation zones are highly influenced by these parameters. However, it seems that the CRZ dimensions/strength does not play an important role in the blowoff, whilst the composition of the mixture shows high correlation. Nevertheless, the CRZ intensity using these compositions can increase residence time, important for combustion improvement of other blends.

The objectives of this study (baseline study, n = 20) were to implement Matlab procedures for quantifying selected static balance variables, establish baseline data of selected variables which characterize static balance activities in a population of healthy young adult males, and to examine any trial effects on these variables. The results indicated that the implementation of Matlab procedures for quantifying selected static balance variables was practical and enabled baseline data to be established for selected variables. There was no significant trial effect. Recommendations were made for suitable tests to be used in later studies. Specifically it was found that one foot-tiptoes tests either in static balance is too challenging for most participants in normal circumstances. A one foot-flat eyes open test was considered to be representative and challenging for static balance.

This study is aimed at investigating the interactive effect of reaction variables on the composition and octane number of reformat in catalytic naphtha reforming gasoline fuel. The relationship between aromatization activity and RON, with three reaction variables, namely temperature (480–510 °C), total pressure (10–30 bar) and space velocity LHSV (1.2–1.8 h⁻¹) were presented as empirical mathematical models. Experiments were performed based on the central composite rotatable design and analyzed using response surface methodology (RSM) and canonical analysis. First, the equation models are used to predict RON and aromatization activity as responses. Second, the regression analysis of RON and aromatization activity equations is obtained from the output of these developed models. Finally, the RSM is used to optimize these regression empirical models. R ² = 88.5 % for RON and 80.5 for the aromatization activity showed that RSM models fitted well with the observed data and considered to be accurate and available for predicting responses. The temperature and total pressure are the most effective variables as a linear (X 1 , X 2) terms and have a significant role in the responses. Numerical results also revealed that the maximum predicted RON of 105 was attained at optimum reaction temperature of 515 °C, operating pressure of 17 bar and LHSV of 2.0 h⁻¹.