The development and implementation of condition monitoring system become very important for wind industry with the increasing number of failures in wind turbine generators due to over temperature especially in offshore wind turbines where higher maintenance costs than onshore wind farms have to be paid due to their farthest locations. Monitoring the wind generators temperatures is significant and plays a remarkable role in an effective condition monitoring system. Moreover, they can be easily measured and recorded automatically by the Supervisory Control and Data Acquisition (SCADA) which gives more clarification about their behavior trend. An unexpected increase in component temperature may indicate overload, poor lubrication, or possibly ineffective passive or active cooling. Many techniques are used to reliably predict generator's temperatures to avoid occurrence of failures in wind turbine generators. Multiple Linear Regression Model (MLRM) is a model that can be used to construct the normal operating model for the wind turbine generator temperature and then at each time step the model is used to predict the generator temperature by measuring the correlation between the observed values and the predicted values of criterion variables. Then standard errors of the estimate can be found. The standard error of the estimate indicates how close the actual observations fall to the predicted values on the regression line. In this paper, a new condition-monitoring method based on applying Multiple Linear Regression Model for a wind turbine generator is proposed. The technique is used to construct the normal behavior model of an electrical generator temperatures based on the historical generator temperatures data. Case study built on a data collected from actual measurements demonstrates the adequacy of the proposed model.

Current and future applications of small gas turbine engines annular type combustors have requirements presenting difficult disputes to the combustor designer. Reduced cost and fuel consumption and improved durability and reliability as well as higher temperatures and pressures for such application are forecast. Coupled with these performance requirements; irrespective of the engine size; is the demand to control the pollutant emissions, namely the oxides of nitrogen, carbon monoxide, smoke and unburned hydrocarbons. These technical and environmental challenges have made the design of small size combustion system a very hard task. Thus, the main target of this work is to generalize a calculation method of annular type combustors for small gas turbine engines that enables to understand the fundamental concepts of the coupled processes and to identify the proper procedure that formulate and solve the problems in combustion fields in as much simplified and accurate manner as possible. The combustion chamber in task is designed with central vaporizing unit and to deliver 516.3 KW of power. The geometrical constraints are 142 mm & 140 mm overall length and casing diameter, respectively, while the airflow rate is 0.8 kg/sec and the fuel flow rate is 0.012 kg/sec. The relevant design equations are programmed by using MathCAD language for ease and speed up of the calculation process.

Network layer indications are not readily available upon a link change; therefore, general dependes on the network layer may introduce unnecessary delays due to network layer signaling for a simple link layer handover. If information could be gathered at link layer to determine the need for network layer signaling, then both the delay and signaling load could be really improved over the current standards of Mobile IP.

This paper presents a Cross-layer decision on two layer network and link layers to improve the performance of Enhanced Mobile IP (E-Mobile IP) handover in which reducing packet loss and latency during handover process.

Abstract

This paper is conducted to compare the determinants of profitability of the domestic and foreign Islamic banks operating in Malaysia. The Generalized Least Square (GLS) is employed with unbalanced panel data on seventeen Islamic banks, using quarterly data for the period of 2007 to 2010. In order to find out the differences in the profitability determinants, the sample of banks is divided into two sub-samples (domestic and foreign). The results reveal that domestic Islamic banks are more profitable than foreign Islamic banks. The results also show that the profitability determinants of domestic banks are different from those of foreign banks. The overhead expenses, loans, efficiency, gross domestic product growth rate and bank size have a significant effect in determining banks’ profitability, in which case applicable to the domestic banks only. In turn, the gross domestic product per capita has a significant effect in determining banks’ profitability of only the foreign banks. The study finds that, deposits, capital and reserves, inflation and banks’ age have a significant effect in determining banks’ profitability of both domestic and foreign banks. Meanwhile, liquidity and concentration are not able to explain the variability of domestic and foreign Islamic banks’ profitability. The findings indicate that the profitability of domestic banks is affected by the global financial crisis while, the profitability of foreign banks is not affected.

In this work, in addition to the 16-corrugation that have been tested, three more models with same dimensions and different corrugation density have been tested too. 18-corrugation, 20-corrugation, and 22-corrugation (RCCT-18, RCCT-20, and RCCT-22) have been investigated. Here, it is wise to mention that all corrugations have the same shape and dimensions. Moreover, 22 corrugations were found the maximum number of corrugations that can be fabricated in the tube circumference. In other words it was impossible to fabricate a tube with more than 22-corrugations at that certain diameter, since all tested composite tubes have the same length and diameter at all testing phases. Results show that corrugation density has an influence on the performance of composite shells as an energy absorber. It has been found that as corrugation density increases, total energy absorption increases.

Today the use of composite materials in different kinds of applications is accelerating rapidly. Composite materials have become common engineering materials and are designed and manufactured for various application. This paper involves an experimental program including testing the capabilities of hybrid material s (composite and metallic materials) as an energy absorber. The method of approach has been to fabricate and test a series of specimens. The specimens have cylindrical shape; they are fabricated using hand lay-up technique. Hybrid specimens involve two subtypes: metallic cylinder surrounded by three layers of composite cylinder referred as M/C, and three layers of composite cylinder form the internal part surrounded by metallic cylinder referred as C/M (Fig.1). Hybrid model are subjected to lateral quasi static compression load.

• Pavement distress is an indication of pavement layer deterioration. There are many types of deterioration; however, rutting, defined as the permanent deformation forming longitudinal surface depressions in the wheel paths, is one of the most important kinds of distress that affect the safety and the ride quality of flexible pavement. The main objective of this study was to develop an empirical pavement rutting model for the wet freeze zone, which is one of the four long term pavement performance (LTPP) climate zones, to predict the depth of pavement rutting on granular bases. Using the LTPP database, the study aimed at a better understanding of the pavement rutting phenomena and the factors that may affect pavement rutting. Multiple regression analysis was performed to develop a flexible pavement rutting model. The proposed model was developed based on the relationship between the response variable rut depth and predictor variables of traffic loads, structural number, Marshall stiffness, air voids in the total mix, and voids in the mineral aggregate. It was found that traffic loads was the predominant factor that have a significant effect on pavement rutting, which agrees with the existing literature, as well as engineering knowledge and practice. Following the traffic loads, structural number was the most significant secondary factor, followed by percent of voids in the total mix, voids in the mineral aggregate, and Marshall stiffness.

Cutting samples (n = 93) from the Sirte, Tagrifet, Rakb, Rachmat, Bahi Formations of Upper Cretaceous and Nubian Formation (Lower Cretaceous) derived from eleven wells (6C1-59, 6J1-59, 6R1-59, KK1-65, OO2-65, M1-51, KK1-65, B-96, B-95, B-99, E1-NC-59) locate in the Amal, Gialo, Nafoora, and Sarir Fields present in East Sirte Basin were analysed in the aim of their organic geochemical evaluation. A bulk geochemical parameters and evaluation of specific biomarkers by chromatography-mass spectrometry (GC-MS) implemented to find out a diversity of interbedded non-marine lithofacies including sandstones, siltstones, shales and conglomerates. Such rocks are good source and contain fair to good contented of organic matter passing in the course of very good, in which the excellent source rocks have organic carbon richness (TOC) reached to 5.16 wt%. The studied samples are ranged from gas to oil-prone organic matter (OM) of hydrogen index (HI) ranged between 115 - 702 mg HC/g TOC, related with gas prone (OM) of (HI) <150 and most beds contain oil-prone organic matter of (HI) > 300, associated with oxygen index (OI): 3 - 309 mg CO2/g TOC indicate that organic matter is dominated by Type II/III kerogen. The maturity of these source rocks is variations ranges from mature to post-mature-oil window in the Sirte and Rachmat Formations, as inferred from the production index (PI: 0.07 - 1.55) and Tmax and Ro% data (Tmax: 425 - 440/Ro%: 0.46 - 1.38) and early to mid-stage maturities for the other formations. Low PI in some samples seems to imply that the most of the hydrocarbons have expelled and migrated from the rocks. Biomarker ratios of individual hydrocarbons in rock extracts (n = 21), were also used in order to investigate the samples’ thermal maturity and palaeo depositional conditions. Pristine/Phytane ratios of 0.65 - 1.25 and dibenzothiophene to phenanthrene (DBT/P) ratios of 0.04 - 0.47 indicated Anoxic and suboxic conditions of depositional source rock. The origin of OM of the studied samples attributed to a marine algal source as indicated from the dominated by the C27 and co-dominant C28 homologues sterane in molecular composition distributions. The marine shale and carbonate lithofacies of rock samples were also indicated by high C19TT/C23TT ratio and low relative abundance of C24TeT/C23TT, consistent with their interpreted marine affinity. An organic geochemical evaluation pointed out that the Sirte Shale formation (Campanian/Turonian) is the main source rock in this petroleum area.