Including the influence of waves in the overall slope stability analysis of rubble mound breakwaters

An offshore breakwater is designed for the construction of a LNG-terminal. For the slope stability analysis of the rubble mound breakwater the existing and the extreme wave climate are considered. Pore water pressure variations exist in the breakwater and its permeable foundation. A wave trough combined with the moment of maximum wave run-up results in a decrease and increase of the pore water pressure, respectively. Therefore, the wave actions have on overall effect on the slope stability of the breakwater. To include the wave actions in the slope stability analysis a simplified method is used. For the slope stability analysis, a specific piezometric line is determined. This piezometric line consists of a wave profile and the profile of wave run-up. The slope stability analysis are performed with GEO-SLOPE/W 2007. For the geotechnical design of the breakwater load cases of extreme and normal waves combined with, respectively, extreme and normal water levels are analysed. All the load cases which included the wave actions result in lower stability safety factors than the load cases with only still water levels. Therefore the wave actions are the determining load case for the geotechnical stability of the breakwater and it should be studied in detail

Streamlining Digital Modeling and Building Information Modelling (BIM) Uses for the Oil and Gas Projects

The oil and gas industry is a technology-driven industry. Over the last two decades, it has heavily made use of digital modeling and associated technologies (DMAT) to enhance its commercial capability. Meanwhile, the Building Information Modelling (BIM) has grown at an exponential rate in the built environment sector. It is not only a digital representation of physical and functional characteristics of a facility, but it has also made an impact on the management processes of building project lifecycle. It is apparent that there are many similarities between BIM and DMAT usability in the aspect of physical modeling and functionality. The aim of this study is to streamline the usage of both DMAT and BIM whilst discovering valuable practices for performance improvement in the oil and gas projects. To achieve this, 28 BIM guidelines, 83 DMAT academic publications and 101 DMAT vendor case studies were selected for review. The findings uncover (a) 38 BIM uses; (b) 32 DMAT uses and; (c) 36 both DMAT and BIM uses. The synergy between DMAT and BIM uses would render insightful references into managing efficient oil and gas’s projects. It also helps project stakeholders to recognise future investment or potential development areas of BIM and DMAT uses in their projects

Idiopathic multifocal choroiditis

Idiopathic multifocal choroiditis (MFC) and/or punctate inner choroidopathy (PIC) describe a chronic progressive bilateral inflammatory chorioretinopathy that predominantly affect healthy myopic white women with no known associated systemic or ocular diseases. The principal sites of involvement are the retinal pigment epithelium (RPE) and outer retinal spaces; the choroid is not affected during the active phase of the disease. Idiopathic MFC with atrophy is a recently described variant. Although there is no generally accepted standard treatment, anti-inflammatory and anti-VEGF (vascular endothelial growth factor) agents are necessary in the acute stage to control the inflammation and choroidal neovascularization (CNV)

The ghost solid methods for the elastic–plastic solid–solid interface and the ϑ-criterion

Two variants of the Ghost Solid Method (GSM), namely the Original GSM (OGSM) and Modified GSM (MGSM), are proposed for the elastic–plastic solid–solid interactions in a Lagrangian framework. It is shown that the OGSM is highly problem related and can lead to large numerical errors under certain material combinations or in the presence of the wave propagation through the solid–solid interface. The ϑ-criterion, previously developed for the elastic–elastic solid–solid interactions [1], has been applied to the OGSM for the elastic–plastic interactions. It is shown that this criterion can successfully detect the onset of these large errors. Moreover, it is shown that it can be used to determine the reliability of the results obtained using the OGSM. The MGSM has been shown to be able to remove the large numerical errors that would normally arise due to the OGSM. Next, the extension of the two variants of the GSM, to two-dimensional settings, is presented for two idealized interface conditions, namely the no-slip condition, and the perfect-slip conditions. Numerous numerical experiments are provided attesting to the effectiveness and viability of the GSMs, for simulating wave propagation at the elastic–plastic solid–solid interface. The applicability of the ϑ-criterion is also studied in the numerical experiments

Integrated Oil-Field Management: From Well Placement and Planning to Production Scheduling

Integrated management can benefit oil-field development and exploitation tremendously. It involves holistic decisions on the order, placement, timing, capacities, and allocations of new well drillings and surface facilities such as manifolds, surface centers, and their interconnections, along with well production/injection profiles. These decisions have profound long-term impacts on field productivity; however, the dynamic nature of oil reservoirs makes them strongly intertwined and highly complex. Hence, a dynamic, holistic, and integrated approach is necessary. Most existing well placement studies ignore surface effects and drilling-rig availability and assume that all wells are opened simultaneously at the beginning of the production horizon. In this work, we extend our previous study [Tavallali Ind. Eng. Chem. Res. 2014, 53 (27), 11033] and develop a mixed integer nonlinear programming (MINLP) approach for addressing such limiting assumptions. We develop a revised outer-approximation algorithm involving two multiperiod, nonconvex MINLPs and several local search strategies. Numerical results for a literature example show significant improvement in the net present value for oil-field development

Preconcentration and Determination of Zinc and Lead Ions by a Combination of Cloud Point Extraction and Flame Atomic Absorption Spectrometry

The phase-separation phenomenon of non-ionic surfactants occurring in aqueous solution was used for the extraction of lead(II) and zinc(II). After complexation with 3-[(4-bromophenyl) (1-H-inden-3-yl)methyl]-1 H-indene (BPIMI), the analytes were quantitatively extracted to a phase rich in Triton X-114 after centrifugation. Methanol acidified with 1 mol/L HNO(3) was added to the surfactant rich phase prior to its analysis by flame atomic absorption spectrometry (FAAS). The concentration of bis((1H-benzo [d] imidazol-2y)ethyl)sulfane, Triton X-114, pH and amount of surfactant were all optimized. Detection limits (3 SDb/m) of 2.5 and 1.6 ng/mL for Pb(2+) and Zn(2+) along with preconcentration factors of 30 and an enrichment factor of 32 and 48 for Pb(2+) and Zn(2+) ions were obtained, respectively. The proposed cloud point extraction was been successfully applied for the determination of these ions in real samples with complicated matrices such as food and soil samples, with high efficiency