Burst Test Simulation of Corroded Pipelines

Pipelines are the safest and reliable way for oil and gas transmission. Failures due to corrosion defects are of major concern in maintaining pipeline integrity. A number of solutions have been developed for the assessment of remaining strength of corroded pipelines. Methods of assessing the corrosion metal loss defects have been available for decades, for instance the ASME B31G method. ASME B31G and Recommended Practice DNV-RP-F101 are the available coded methods that are used as reference codes for corroded pipelines. They provide guidelines for evaluating the remaining strength of corroded pipelines subjected to internal pressure loading and combined with longitudinal compressive stresses for single defect, multiple defects and etc. In this project, a corroded pipe will be simulated using ANSYS Software. The Finite Element Analysis (FEA) simulations will be conducted for various idealized geometry of the corrosion defects subjected to internal pressure loading only. The results from the simulations will then be compared to the coded methods; ASME B31G, DNV-RP-F101 and the experimental results. The Maximum Allowable Burst Pressure (Pb) and the best approach for evaluating the remaining strength of corroded pipelines will be determined from the simulation

Large-Area Synthesis and Growth Mechanism of Graphene by Chemical Vapor Deposition

There has been continuous progress in the development of different synthesis methods to readily produce graphene at a lower cost. Compared with the other methods, chemical vapor deposition (CVD) is an effective and powerful method of producing graphene and has attracted increased attention during the last decade. In this way, we can obtain good uniformity with a multitude of domains, excellent quality, and large scale of the produced graphene. Meanwhile, it is also helping for large-area synthesis of single-crystal graphene. In the CVD method, precursors are typically absorbed on the surface followed by pyrolytic decomposition, which leads to the generation of absorption sites on the surface and promotes the growth of continuous thin films

Size-dependent calcium carbonate precipitation induced microbiologically in aerobic granules

Calcium and ash accumulation in aerobic granules treating organic wastewater was investigated systematically in this study. It was found that ash content of granular sludge reached 43% at stable state of reactor operation with calcium carbonate precipitation as the main cause. Since granular sludge in the reactor at the steady state was the mixture of granules with different sizes, granules in the reactor on operation days 90, 120 and 150, respectively, were sorted into 10 categories by size to study the inorganic substances. It was found that calcium was selectively enriched in granules and the precipitation of calcium carbonate was just dependent on granule size instead of operation duration at the steady state. More calcium carbonate was precipitated in bigger aerobic granules, but both calcium and ash contents reached stable values when granule size was bigger than 700 ?m. Analysis by X-ray diffractometer disclosed that aragonite was the only polymorph of calcium carbonate detected in aerobic granules with size bigger than 300 ?m. Scanning electron microscope revealed clearly for the first time that bundles of needle shaped aragonite was embedded in extracellular polymeric substances of aerobic granules. A mechanism on calcium carbonate precipitation was proposed to deepen the understanding of biomineralization

Synthesis of Carbon Nanotubes by Catalytic Chemical Vapor Deposition

As a new carbon material in the twenty-first century, carbon nanotubes (CNTs) have excellent optical, electrical, magnetic, thermal, chemical, and mechanical properties. There are many synthesis methods to produce CNTs. Compared with other methods, chemical vapor deposition (CVD) is the most effective method that has broad prospects for large-scale control of CNTs in recent years due to its simple equipment, simple operation, and lower cost. In order to gain a comprehensive understanding of the controlling parameters about the formation of CNTs, this chapter reviews the latest progress in the preparation of CNTs by CVD from three of the most important influencing factors: carbon sources, catalysts, and substrates. Among them, the catalyst is the most influential factor for the morphology, structure, and properties of CNTs. It should be pointed out that many growth factors can control the particle size distribution, composition, and structure of the catalysts, such as catalyst substrate, metal transition components added, calcination temperature, etc