Due to the increase in the number of failures in the wind turbine generators, the condition monitoring system plays a significant role in overcoming the negative effects resulting from the difficult operation conditions. Mechanical and electrical properties can be combined to detect the faults coming from wind turbine generators by analyzing their behavior under different (normal and abnormal) operation conditions. Studying the trend and effect of the electrical torque pulsations on wind turbine generators under different conditions allows for a proper condition monitoring. In this paper, different methodology has been adopted to develop a proper condition monitoring system on the wind generators by evaluating the generator electrical torque based on mechanical torque and taking into account the acceleration torque, which has not been considered in previous work. Using the electric torque with respect to the rotor angular speed of the generator, when it is running under different operation conditions, indicates the generator health, which is the main methodology of the proposed work. A case study, which is based upon collected data from actual measurements, is presented in this work in order to demonstrate the adequacy of the proposed model.

Due to the increase in the failures of the wind generators, Condition Monitoring System (CMS) plays a significant role in overcoming these failures resulting from the harsh operation conditions. The mechanical, thermal, and electrical analyses can be utilized to detect the faults, which are coming from the wind generators by monitoring the changes in their characteristics under different (normal and abnormal) operation conditions. Observing the trend of the electrical torque pulsations of the wind generators under different conditions is beneficial to perform proper condition monitoring. In this paper, different methodology has been adopted to implement a proper condition monitoring system on the wind generators by evaluating the generator electrical torque based on the mechanical and the acceleration torque. Then, in order to specify the generator faults, the trend of the electrical torque with respect to the rotor angular speed of the wind generator under different operation conditions is analyzed. Further, the rate of change in the generator temperature is considered as well as an indicator to define the health of the wind generators with respect to the induced electrical torque, because of the negative effect of the elevated generator temperature on the induced electrical torque. Case study, which is based upon collected data from actual measurements, is presented in this work in order to demonstrate the adequacy of the proposed model.

Purpose – The purpose of this paper is to investigate quality factors that are absolutely essential for successful implementation of total quality management (TQM) in Libyan oil and gas companies (LOGCs). Design/methodology/approach – In all, 11 quality factors with 42 elements were identified to develop a questionnaire to carry out the survey in order to identify the quality factors that are seen by LOGCs to be critical to the success of TQM implementation. In total, 45 questionnaires were provided by hand to quality-related managers from the Libyan oil and gas sector. A total of 42 were returned sufficiently completed, that gave us a response rate of approximately 93.33 per cent. Findings – The empirical analysis demonstrates several key findings: the analysis indicated that 24 quality factors are found to be critical and absolutely essential for successful TQM implementation. These factors classify into three levels of criticality. All of the factors were found to be supported by similar studies and cited literatures. Research limitations/implications – The research is subject to the normal limitations of survey research. The study is using perceptual data provided by quality managers and engineers which may not provide clear picture. It may be suitable to consider gathering information from various stakeholders such as employees, customers, suppliers and even competitors. However, this can be overcome using multiple methods to collect data in future studies. Interestingly, the findings here may be generalisable outside Libya, i.e. South Mediterranean countries. Practical implications – LOGCs should consider TQM as an innovative tool for improving business performance in today’s competitive environment. The findings suggest that the TQM critical success factors should be implemented completely as a whole package rather than on a fragmented basis to get the full potential of the TQM. Originality/value – The study investigate the critical quality factors for successful TQM implementation which will direct an organisation towards business excellence and enhancing success of TQM practices in the oil and gas sector. Very few studies have been performed to investigate and understand this issue. Therefore, the research can make a useful contribution

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.

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.

Compiler writers have developed various techniques, such as constant folding, subexpression elimination, loop transformation and vectorization, to help compilers in code optimization for performance improvement. Yet, they have been far less successful in developing techniques or cost models that compilers can rely on to simplify parallel programming and tune the performance of parallel applications automatically. This paper is the first of two-phase study to develop an analytical model that can be used to estimate the cost for sequential and parallel execution of array expressions on multicore architectures. While this paper discuss the possibility of developing a cost model to estimate the sequential execution of array expressions on a single CPU, the second part of the investigation shall focus on developing a model to estimate parallel execution of arrays on multicore platforms. The model presented in this paper is expected to be used by programming language compilers as complement component with the other model to estimate and subsequently decide whether to parallelize individual array expressions or not. The preliminary results which are presented here show that this model can give a satisfactory evaluation and high-precision estimation for the cost of executing a regular array expression on a single core processor.

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.

Abstract—this work reports on a high speed flexible automation system based on Cartesian multi-axis coordinate system linear step motor developed, in the target application as a multi-use robot system. The task of this work is to constructs an interactive multimedia page for study and researches the principle’s work of drive of direct action linear step motor, Development the mathematical model and implementation of a closed loop control, based MATLAB/SIMULINK, Study the static and dynamic characteristics of the motor movement which is restricted to the trajectories accessible through the given commands.