The present paper involves a detailed evaluation of specific steroid biomarkers by gas chromatography– mass spectrometry (GC–MS) and GC-metastable reaction monitoring (MRM) analyses of several crude oils and source rocks from the East Sirte Basin. 24-Norcholestanes, dinosteranes, 4a-methyl-24-ethylcholestanes and triaromatic steroids have been identified in both source-rocks and crude oils of the East Sirte Basin. Diatoms, dinoflagellates (including those potentially associated with corals) and/or their direct ancestors are amongst the proposed sources of these biomarkers. These biomarker parameters have been used to establish a Mesozoic oil–source correlation of the East Sirte Basin. Hydropyrolysis of an extant coral extract revealed a similar distribution (although immature) of dinosteranes and 4a-methyl-24-ethylcholestanes also observed in the Sirte oils and source-rocks. This is consistent with the presence of dinoflagellates present during the deposition of the Mesozoic aged East Sirte Basin Formations. A good data correlation for the rock extracts revealed a similar distribution of 3,24-dimethyl triaromatic steroids, 3-methyl-24-ethylcholestanes, 4-methyl-24-ethylcholestanes and 2-methyl-24-ethylcholestanes observed in one of the oil families and associated source-rocks for the East Sirte Basin.

This paper presents a method of generating realistic electricity load profile data for the UK domestic buildings. The domestic space features have been investigated excluding the heating and hot water systems. A questionnaire survey was conducted and the feedback were collected from a number of occupants at different intervals of times on daily bases in order to establish the probabilistic record of the estimated use of electrical appliances. The model concept of this study also considers the results of previous investigations such as that available in public reports and statistics as input data elements to predict the global domestic energy consumption. In addition, the daily load profile from individual dwelling to community can be predicted using this method. The result of the present method was compared to available published data and has shown reasonable agreement.

Abstract:

Voltage instability problems in power system are an important issue that should be taken into consideration during the planning and operation stages of modern power system networks. The system operators always need to know how far the power systems from voltage collapse in order to apply suitable actions to avoid unexpected results. This paper propose a review of some static voltage stability inddices found in the literature to study voltage collapse reveals that various analytical tools based on different concept to predict voltage collapse phenomena. These static voltage stability indices present reliable information about the closeness of the power system to voltage collapse and indentification of the weakest bus, line and area in the power network. A number of static voltage stability indices have been proposed in the literature, but in this only four of them will be considered. The effectiveness of these indices is demonstrated through studies in IEEE 14 bus reliability test system. The results are discussed and key conclusion presented.

A numerical simulation of a two-stage reciprocating compressor has replicated the operations of the compressor under various conditions for the development of diagnostic features for predictive condition monitoring. The simulation involves the development of a mathematical model of five different physical processes: speed–torque characteristics of an induction motor, cylinder pressure variation, crankshaft rotational motion, flow characteristics through valves and vibration of the valve plates. Modelling both valve leakage and valve spring deterioration has also been achieved. The simulation was implemented in a MATLAB environment for an efficient numerical solution and ease of result presentation. For normal operating conditions, the simulated results are in good agreement with the test results for cylinder pressure waveforms and crankshaft instantaneous angular speed (IAS). It has been found that both the IAS 

Historically, applications for traditional phenolic resin/polyurethane materials are limited due to the inherently weak thermal stability of urethane-phenolic linkage and slow reaction rate. A novel concept has been developed to produce phenolic resin/polyurethane copolymers ...

The unique features of polybenzoxazines make them attractive for a wide range of applications. The characteristics of polybenzoxazines such as excellent dimensional stability, lower surface energy, higher Tg, and lower moisture absorption are attributed to the stable intramolecular hydrogen bonding in their network structure. The features make polybenzoxazines excellent candidates for the applications that require near zero shrinkage and high dimensional stability. Polybenzoxazines are formed by the autocatalytic polymerization of benzoxazine monomers. Polybenzoxazines are well known as a new class of thermoset polymers used for high performance applications. They provide the characteristic properties found in phenolic resins, such as high thermal stability, excellent electrical properties, good mechanical properties, and better flame retardancy. Furthermore, they have the advantages …

 This study is a comparison between English and Arabic vowels. First a description and classification of vowels in the two languages is given. Then the two sets of vowels are contrasted to find which vowels are similar and which are not. Finally, the set of similar sounds are analysed acoustically to find out to what extent they are similar. This is done by recording two sets of words containing these vowels and measuring their formants and duration. The findings show that although these sounds are similar in some aspects, Arab learners of English do not replace English vowels with their Arabic counterparts but, instead they try to reach the target sounds even though they are not completely successful in achieving their goal. 

In the introduction of this paper the aims, the subject and its importance are briefly stated. However, the paper consists of two main parts. The first part deals with the segmental phonology of Tripolitanian Arabic and this includes classification of both vowels and consonants and relevant features such allophonic variation, length, geminating and clusters. The second part, on the other hand, deals with the suprasegmental level of the dialect and in which its syllable structure and stress pattern are discussed. In the conclusion, the findings of the research are summarised and some recommendations for further research are given.