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Characterisation of Ring Testing in the Design of Offshore Oil Transportation Systems
Get PDFThe manufacturing procedure qualification tests (MPQT) of offshore pipelines projects has recently started to rely on ring collapse tests, which consist in testing a short section (50 mm) of a full scale joint. This approach is capable of providing valuable insight into the collapse behaviour of offshore pipelines and has practical, financial and logistic benefits.Detailed analytical and numerical work has been carried out in order to understand the collapse mechanisms and the influence of several parameters, like geometry, material strength and seal friction, on the collapse behaviour has been investigated.It is found that the shape of the initial imperfection and the seal friction can both affect the collapse and produce a variation in the value of the collapsing pressure
Physical-Chemical Properties of Water-in-Diesel Fuel Emulsions
Get PDFThe addition of water dispersed phase into the diesel continuous phase will lead to the formation of water-in-diesel (W/D) emulsion, which significantly reduces the pollution level of NOx and particulate matters in the diesel engines. Small amount, 0.2% by volume, of surfactant material was necessary in the preparation of a stable W/D emulsion. The study of the physical and chemical properties of stable W/D emulsions is important to understand the flow behavior characteristics of these emulsions. Pure diesel fuel and three samples of W/D emulsions (10%, 20% and 30% by volume water) were examined in this study. The following properties are measured according to the corresponding ASTM standards for the pure diesel and its emulsions with 10%, 20% and 30% water: heating value, pour point, flash point, distillation data, density, viscosity, calculated cetane index, total acid number, and sulfur content. The addition of water in the emulsion caused a drop in the calorific value, final boiling point, cetane index, total acid number, and sulfur content. Increasing the water also increased the pour point, flash point, and density
Photoinduced Phenomena in Thermally Evaporated a-Gex Se90-x Sb10 Thin Films
Get PDFAmorphous Gex Se90-x Sb10 thin films were prepared by thermal evaporation under vacuum onto glass substrates. Reflectance and transmittance were measured in the wavelength range 190-900nm. The optical properties of the as deposited and UV-irradiated films at different exposure times were reported. The compositional dependence of the optical constants (absorption coefficient, the non-direct optical gap Eg, refractive index (n), and the extinction coefficient (k) were evaluated and discussed in terms of the Ge content and the chemical bond network model
Development of Artificial Neural Network Models for Biogas Production from Co-Digestion of Leachate and Pineapple Peel
Get PDFThe processes of anaerobic digestion and co-digestion are complicated and the development of computational models that are capable of simulation and prediction of anaerobic digester performances can assist in the operation of the anaerobic digestion processes and the optimization for methane production. The artificial neural network approach is considered to be an appropriate and uncomplicated modelling approach for anaerobic digestion applications. This study developed neural network models to predict the outcomes of anaerobic co-digestion of leachate with pineapple peel using experimental data. The multilayered feed forward neural network model proposed was capable of predicting the outcomes of biogas production from the anaerobic co-digestion processes with a mean squared error for validation of 2.67 x 10-2 and a R value for validation of 0.9942. The approach was found to be effective, flexible and versatile in coping with the non-linear relationships using available information
Cost Analysis of Water Purification Methods in India
Get PDFIn this work, cost analysis of commonly used RO method, Ultra-Violet method and the new Pressure Cooker method is performed. These methods studied here relate to the production of potable water which meets the World Health Organization (WHO) standards. The advantages of the use of the Pressure Cooker method over the two other methods for undeveloped countries are explained.The results show that not only the Pressure Cooker method is most economical but also is very versatile as far as its use in rural India or other under-developed countries are concerned
Assessment of Municipal Solid Waste Clay Liner System Using Consolidation Test
Get PDFThe present study has been carried out to provide landfill clay liner soil with admixture microsilica in different proportions. The geoenvironmental and physico-chemical characteristics were carried out to characterize the clay mixed with definite portion of microsilica in mass ratio. An experimental investigation was performed to determine the effect of clay and microsilica consolidation of leachate. The microsilica- clay composites were mixed in ratios of 0:100, 1:10 and 1:20 and experiment carried out with leachate as the permeation liquid. The quantitative reductions in coefficient of permeability increase in the effective stress for the all ratios. The chemical reaction of water and soil are lower than that in the leachate. In real field the leachate as permeation liquid after construction of liners, is retained by adding microsilica in clay liner system. 1:10 ratio of microsilica-clay composites was found to be more suitable municipal solid waste leachate as permeating liquid
The World's Largest Anomalies of Electrical Conductivity and their Nature - A Review
Get PDFGeoelectrical parameters, structure and geologic-tectonic position of a number of largest anomalies of electrical conductivity on different continents of the planet Earth are analyzed against the background of published and some new experimental data. Criteria of dividing nomalies into fluid and electronically conducting varieties, and their relation with mineral deposits are considered. In Memory of Sergey Kuli
A Study on the Effect of Solar Fraction on the Environmental Performance of Solar Air-Conditioning by an Adsorption Chiller
Get PDFSolar air-conditioning (AC) is a sustainable air-conditioning system but a back-up heater is needed because a solar AC has intermittent output. This study presents the effect of ratio of heat delivered by solar to the total heat delivered to an adsorption chiller (solar fraction) on the environmental performance of a solar AC system. This AC system need covers cooling demand for an office building in Malaysia. Cooling demand of the building was simulated using well-known building energy analysis software, Equest. Flat-plate collectors and an adsorption chiller were the main component of the solar AC system. Flat-plate collecters were simulated using another software, Watsun, and the adsorption chiller was based on the author simulation model that is comparable with other studies. Environmental performance was analyzed by emission ratio of a boiler and power plants. Solar fraction of 0.33, 0.74 and 0.98 were studied. It was found that solar AC by an adsorption chiller can cover the cooling demand of the office building throughout the year. It was also found that a gas fired boiler is a better auxiliary heater than an electric heater because of the direct conversion of heat from fuel. Less emissions is emited at higher SF compared to conventional AC for all cases of back-up heater. A solar AC must has solar fraction higher than 74% to ensure it emits less emissions than a conventional AC system
CFD Benchmark Tests for Indoor Environmental Problems: Part 1 Isothermal/Non-Isothermal Flow in 2D and 3D Room Model
Get PDFCommercially available Computational Fluid Dynamics (CFD) software have been applied in indoor environmental design in recent years, but the prediction accuracy depends on an understanding of fluid dynamics fundamentals, in setting appropriate boundary and numerical conditions. This study aims to provide practical modelling information related to prediction accuracy and problematic areas in CFD applications in air conditioning and ventilation, through a series of benchmark tests and reported the results. Six commercial CFD codes were evaluated while two benchmark test cases were performed on isothermal/non-isothermal flow in 2D and 3D room models. The influence of mesh design, and turbulence models showed that using a standard k-ε model on a coarse mesh could provide sufficiently accurate results for practical purposes, by reducing the relaxation coefficient. Evaluation using different CFD programs on a non-isothermal room airflow showed different performances in predicting temperature distributions. The OpenFOAM code showed the closest matching results between three codes tests
Semi-Emperical Model to Determine Liquid Velocity and Pressure Loss of Two-Phase Flow in A Horizontal Bend–Part I (Stratified Flow)
Get PDFThe objectives of this study are to conduct a thorough literature review on the subject of multiphase flow through bends and to develop and evaluate a semi-empirical model to determine liquid velocity and pressure loss during stratified gas-liquid flow in a horizontal bend. The model is based on incorporating the momentum balance equations of both phases (air and water). Extensive experiments were carried out to acquire data using air and water in a 0.05 m diameter horizontal pipe simulator with an intermediate bend of 0.5 m radius of curvature.The results show that due to the disturbance nature of the two-phase flow in general, it is quite convenient to describe the pressure drop in terms of the energy loss. It was also found that stratified flow does not cause a significant change in the energy during the flow along the bend traverse due to its stable nature. The semi-empirical model developed for predicting the superficial water velocity during stratified flow shows an acceptable agreement with the experimental data.The work presented in this paper may help flow assurance, production, pipeline and process engineers to have reliable design and operations through counting for the losses caused by such components