Tangguh Project: In-Service Buckling Design of Offshore Pipelines With Major Uncertainties on Soil Characterization and Seabed Mobility

2021 ◽  
Author(s):  
Sabrina Bughi ◽  
Luigi Foschi ◽  
Lorenzo Marchionni ◽  
Roberta Vichi ◽  
Yansa Zulkarnain
Keyword(s):  
Structural Integrity ◽  
Mitigation Measures ◽  
Soil Characterization ◽  
Operating Life ◽  
Lateral Buckling ◽  
Natural Sand ◽  
Pull Out ◽  
Pipeline Route ◽  
The Impact ◽  
Soil Pipe

Abstract This paper is based on the experience made during the design and installation of an offshore pipeline recently completed in Indonesia, where a 24” subsea production pipeline (16km long in 70m water depth) was found susceptible during design to lateral buckling. Buckling is a well understood phenomenon. However, this project was characterized by major uncertainties mainly driven by soil characterization, soil zonation, soil-pipe interaction, seabed mobility and seabed liquefaction. These uncertainties have played a key role in the in-service buckling design. In particular, extreme pipeline embedment scenarios ranging from fully exposed to fully covered (due to natural sand transportation) were accounted with a significant impact on soil-pipe interaction. To limit the development of excessive strain within the acceptance criteria, a mitigation strategy based on interacting planned buckles has been adopted installing three Buckle Initiators (BI) along the pipeline route. During design great efforts have been spent with the aim to demonstrate the robustness of the proposed solution. 3-D FEM simulations with ABAQUS have been performed taking into account the pipeline route including route curves and the sea bottom profile and the buckle initiators with their main geometries. All uncertainties have been considered following a deterministic approach. The impact of environmental and accidental loads due to a potential trawl-gear interaction were assessed as well. The pipeline susceptibility to lateral and/or upheaval buckling along the sandwave areas has been analyzed as well in order to evaluate the need of mitigation measures suitable to freeze the pipeline configuration during the operating life. Finally, once the lateral buckling design philosophy was established, the cyclic expansion and walking behavior of the pipeline were assessed to verify the pipeline structural integrity at buckles, route curve pull-out and the accumulative pipeline expansion at spools. This paper presents all main engineering aspects faced during design and first feedbacks from field after the pipeline installation.

Lateral Buckling Behaviour of Snake-Lay Pipeline With Vertical Support at Crown

2013 ◽  
Author(s):  
N. Raveendra Reddy
Keyword(s):  
Structural Integrity ◽  
High Pressures ◽  
Large Diameter ◽  
Compressive Force ◽  
Mitigation Measures ◽  
Potential Hazard ◽  
Lateral Buckling ◽  
Axial Compressive Force ◽  
Euler Buckling ◽  
Reliable Solution

Most hydrocarbon pipelines installed recently in the Middle East operate at relatively high pressures and temperatures: maximum inlet operating temperatures >90°C and pressures >135 barg. These pipelines are susceptible to Euler buckling from high axial compressive force induced in the pipeline by the temperature and pressure. Any uncontrolled lateral buckling is a potential hazard for a pipeline’s structural integrity, especially when all compressive force is released at one point and excessive feed-in occurs. Possible mitigation measures include lateral restraint by rock dumping or trenching, or midline spools. Another possibility is to induce the pipeline to buckle in a controlled manner, perhaps at several locations, rather than allowing it to suffer an uncontrolled, large buckle at one location only. This is known as buckle initiation. “Snake-lay” and “Vertical Imperfection” are two methods that have been implemented successfully to initiate controlled buckling. “Buoyancy” is another method, but is yet to be implemented. Snake-lay is a relatively reliable solution but, depending on pipe-soil interaction, sometimes requires a very short radius to initiate the buckle. Installing large diameter pipelines with short radii may invite other problems such as pipeline instability during laying, or may require additional counteracting measures to maintain the specified lay radius. The lay radius can be increased with additional sleepers at the crown of the snake-lay, with a well-defined low friction factor between the pipeline and the support. This paper discusses the behavior of snake-lay pipeline with and without vertical sleeper supports at the crown of the pipeline, and demonstrates what effects supporting the pipeline at the crown will have on the buckling mechanism and the pipeline integrity.

Effect of Specimen Length on Structural and Sealability Evaluation of Tubular Connections in HPHT and Thermal Wells

2021 ◽  
Author(s):  
Jueren Xie
Keyword(s):  
Structural Integrity ◽  
Lateral Buckling ◽  
Specimen Length ◽  
Element Analysis ◽  
Evaluation Program ◽  
Current Test ◽  
Industry Standards ◽  
Test Component ◽  
Connection Design ◽  
The Impact

Abstract Premium connection designs are typically evaluated and qualified to broadly adopted industry standards, such as ISO 13679 (2019) and API RP 5C5 (2017) procedures for testing casing and tubing connection in High Pressure and High Temperature (HPHT) wells up to temperatures of 180°C, and ISO/PAS 12835 (2013) for testing casing connection in thermal wells that experience temperatures from 180°C to 350°C. The primary focus of these qualification protocols is to evaluate the sealing capacity and structural integrity of the candidate connection design under loads representative of the conditions that the connection will experience through the well's life cycle. The test specimens consist of the coupling and the pipe segments on both sides of the coupling. While it may be desirable to evaluate test specimens with lengths equal to that of the field product to capture the temperature, pressure and mechanical loads on the specimen, it is advantageous to limit the length for purposes including handling and controlling the size and cost of the evaluation program. It has been observed that the test results can be affected by the specimen length, so the proper selection of specimen length is a key aspect of these evaluation programs. Current test protocols provide the requirement of a minimum unsupported length for allowing the tests to simulate the strain localization condition. On the other hand, if the unsupported length exceeds a critical value, the test specimens may experience lateral buckling, and preventing buckling adds complexity and cost to the test program. No guidelines have been given in the protocols on the maximum pup length requirement for preventing lateral buckling. Therefore, a better understanding of the impact of specimen length is warranted in order to achieve more reliable and accurate results from the testing program. This paper presents an investigation of the effect of specimen length on the structural integrity and sealability of premium connections based on Finite Element Analysis (FEA). Parametric FEA was completed to determine the impact of specimen length for several sizes of a generic premium connection design under API RP 5C5 (2017) HPHT well and ISO/PAS 12835 (2013) thermal well conditions. Based on the analysis results, recommendations are made to improve and enhance the guidelines for identifying a suitable specimen length for the test component of an evaluation program.

Assessing and mitigating risks to bridges from large wood using satellite imagery

2022 ◽  
pp. 1-21
Author(s):  
D. Panici ◽  
P. Kripakaran
Keyword(s):  
At Risk ◽  
Satellite Imagery ◽  
Structural Integrity ◽  
Rapid Assessment ◽  
Mitigation Measures ◽  
Bridge Structure ◽  
Large Wood ◽  
Impact Forces ◽  
Significant Damage ◽  
The Impact

The transport and accumulation of floating large wood (LW) debris at bridges can pose a major risk to their structural integrity. The impact forces arising from collisions of LW can cause significant damage to piers, and accumulations can constrict the flow and exacerbate scour at piers and abutments. Furthermore, LW accumulations increase afflux upstream of bridges, heightening flood risk for adjoining areas. Consequently, there is a need for a practical and rapid approach to identify bridges prone to LW-related hazards and to prevent the formation of LW accumulations. This paper proposes an approach based on satellite imagery to (i) quantify the risk of LW at a bridge structure and (ii) locate a LW-trapping system upstream of the identified vulnerable bridges to dramatically reduce risks of LW-related damage. This methodology is applied to major rivers in Devon (UK). 26 bridges were identified as at risk to LW with the majority prone to LW jams. Furthermore, satellite imagery was used to identify 12 locations for the potential installation of LW trapping systems for bridge protection. The results reported in this paper show that satellite imagery is a powerful tool for the rapid assessment and plan of mitigation measures for bridges at risk to LW.

Characterizing the effectiveness of COVID-19 mitigation measures: A data-centric approach (Preprint)

2020 ◽  
Author(s):  
Lukman Olagoke ◽  
Ahmet E. Topcu
Keyword(s):  
Control Measure ◽  
Control Measures ◽  
World Health ◽  
Mitigation Measures ◽  
Effective Control ◽  
The World ◽  
Decision Making Processes ◽  
And Performance ◽  
Health Organization ◽  
The Impact

BACKGROUND COVID-19 represents a serious threat to both national health and economic systems. To curb this pandemic, the World Health Organization (WHO) issued a series of COVID-19 public safety guidelines. Different countries around the world initiated different measures in line with the WHO guidelines to mitigate and investigate the spread of COVID-19 in their territories. OBJECTIVE The aim of this paper is to quantitatively evaluate the effectiveness of these control measures using a data-centric approach. METHODS We begin with a simple text analysis of coronavirus-related articles and show that reports on similar outbreaks in the past strongly proposed similar control measures. This reaffirms the fact that these control measures are in order. Subsequently, we propose a simple performance statistic that quantifies general performance and performance under the different measures that were initiated. A density based clustering of based on performance statistic was carried out to group countries based on performance. RESULTS The performance statistic helps evaluate quantitatively the impact of COVID-19 control measures. Countries tend show variability in performance under different control measures. The performance statistic has negative correlation with cases of death which is a useful characteristics for COVID-19 control measure performance analysis. A web-based time-line visualization that enables comparison of performances and cases across continents and subregions is presented. CONCLUSIONS The performance metric is relevant for the analysis of the impact of COVID-19 control measures. This can help caregivers and policymakers identify effective control measures and reduce cases of death due to COVID-19. The interactive web visualizer provides easily digested and quick feedback to augment decision-making processes in the COVID-19 response measures evaluation. CLINICALTRIAL Not Applicable

scholarly journals Potential and limitations of finite element modelling in assessing structural integrity of coralline algae under future global change

2015 ◽  
Vol 12 (19) ◽  
pp. 5871-5883 ◽  
Author(s):  
L. A. Melbourne ◽  
J. Griffin ◽  
D. N. Schmidt ◽  
E. J. Rayfield
Keyword(s):  
Climate Change ◽  
Finite Element ◽  
Structural Integrity ◽  
Geometric Model ◽  
Algal Growth ◽  
Coralline Algae ◽  
Rocky Shores ◽  
Element Analysis ◽  
Scan Data ◽  
The Impact

Abstract. Coralline algae are important habitat formers found on all rocky shores. While the impact of future ocean acidification on the physiological performance of the species has been well studied, little research has focused on potential changes in structural integrity in response to climate change. A previous study using 2-D Finite Element Analysis (FEA) suggested increased vulnerability to fracture (by wave action or boring) in algae grown under high CO2 conditions. To assess how realistically 2-D simplified models represent structural performance, a series of increasingly biologically accurate 3-D FE models that represent different aspects of coralline algal growth were developed. Simplified geometric 3-D models of the genus Lithothamnion were compared to models created from computed tomography (CT) scan data of the same genus. The biologically accurate model and the simplified geometric model representing individual cells had similar average stresses and stress distributions, emphasising the importance of the cell walls in dissipating the stress throughout the structure. In contrast models without the accurate representation of the cell geometry resulted in larger stress and strain results. Our more complex 3-D model reiterated the potential of climate change to diminish the structural integrity of the organism. This suggests that under future environmental conditions the weakening of the coralline algal skeleton along with increased external pressures (wave and bioerosion) may negatively influence the ability for coralline algae to maintain a habitat able to sustain high levels of biodiversity.

scholarly journals Detection of Unknown DDoS Attacks with Deep Learning and Gaussian Mixture Model

2021 ◽  
Vol 11 (11) ◽  
pp. 5213
Author(s):  
Chin-Shiuh Shieh ◽  
Wan-Wei Lin ◽  
Thanh-Tuan Nguyen ◽  
Chi-Hong Chen ◽  
Mong-Fong Horng ◽  
...  
Keyword(s):  
Deep Learning ◽  
Gaussian Mixture Model ◽  
Mixture Model ◽  
Denial Of Service ◽  
Gaussian Mixture ◽  
Mitigation Measures ◽  
Distribution Model ◽  
Ddos Attacks ◽  
Open Set ◽  
The Impact

DDoS (Distributed Denial of Service) attacks have become a pressing threat to the security and integrity of computer networks and information systems, which are indispensable infrastructures of modern times. The detection of DDoS attacks is a challenging issue before any mitigation measures can be taken. ML/DL (Machine Learning/Deep Learning) has been applied to the detection of DDoS attacks with satisfactory achievement. However, full-scale success is still beyond reach due to an inherent problem with ML/DL-based systems—the so-called Open Set Recognition (OSR) problem. This is a problem where an ML/DL-based system fails to deal with new instances not drawn from the distribution model of the training data. This problem is particularly profound in detecting DDoS attacks since DDoS attacks’ technology keeps evolving and has changing traffic characteristics. This study investigates the impact of the OSR problem on the detection of DDoS attacks. In response to this problem, we propose a new DDoS detection framework featuring Bi-Directional Long Short-Term Memory (BI-LSTM), a Gaussian Mixture Model (GMM), and incremental learning. Unknown traffic captured by the GMM are subject to discrimination and labeling by traffic engineers, and then fed back to the framework as additional training samples. Using the data sets CIC-IDS2017 and CIC-DDoS2019 for training, testing, and evaluation, experiment results show that the proposed BI-LSTM-GMM can achieve recall, precision, and accuracy up to 94%. Experiments reveal that the proposed framework can be a promising solution to the detection of unknown DDoS attacks.

scholarly journals Codon harmonization reduces amino acid misincorporation in bacterially expressed P. falciparum proteins and improves their immunogenicity

AMB Express ◽  
2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Neeraja Punde ◽  
Jennifer Kooken ◽  
Dagmar Leary ◽  
Patricia M. Legler ◽  
Evelina Angov
Keyword(s):  
Protein Structure ◽  
Amino Acid ◽  
Codon Usage ◽  
Dna Sequences ◽  
Structural Integrity ◽  
Host Cells ◽  
Loss Of Function ◽  
Species Specific ◽  
And Function ◽  
The Impact

Abstract Codon usage frequency influences protein structure and function. The frequency with which codons are used potentially impacts primary, secondary and tertiary protein structure. Poor expression, loss of function, insolubility, or truncation can result from species-specific differences in codon usage. “Codon harmonization” more closely aligns native codon usage frequencies with those of the expression host particularly within putative inter-domain segments where slower rates of translation may play a role in protein folding. Heterologous expression of Plasmodium falciparum genes in Escherichia coli has been a challenge due to their AT-rich codon bias and the highly repetitive DNA sequences. Here, codon harmonization was applied to the malarial antigen, CelTOS (Cell-traversal protein for ookinetes and sporozoites). CelTOS is a highly conserved P. falciparum protein involved in cellular traversal through mosquito and vertebrate host cells. It reversibly refolds after thermal denaturation making it a desirable malarial vaccine candidate. Protein expressed in E. coli from a codon harmonized sequence of P. falciparum CelTOS (CH-PfCelTOS) was compared with protein expressed from the native codon sequence (N-PfCelTOS) to assess the impact of codon usage on protein expression levels, solubility, yield, stability, structural integrity, recognition with CelTOS-specific mAbs and immunogenicity in mice. While the translated proteins were expected to be identical, the translated products produced from the codon-harmonized sequence differed in helical content and showed a smaller distribution of polypeptides in mass spectra indicating lower heterogeneity of the codon harmonized version and fewer amino acid misincorporations. Substitutions of hydrophobic-to-hydrophobic amino acid were observed more commonly than any other. CH-PfCelTOS induced significantly higher antibody levels compared with N-PfCelTOS; however, no significant differences in either IFN-γ or IL-4 cellular responses were detected between the two antigens.

scholarly journals Effect of Lipopolysaccharides (LPS) and Lipoteichoic acid (LTA) on the Inflammatory Response in Rumen Epithelial Cells (REC) and the Impact of LPS on Claw Explants

Animals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 2058
Author(s):  
Nicole Reisinger ◽  
Dominik Wendner ◽  
Nora Schauerhuber ◽  
Elisabeth Mayer
Keyword(s):  
Epithelial Cells ◽  
Inflammatory Response ◽  
Structural Integrity ◽  
Animal Health ◽  
Lipoteichoic Acid ◽  
Local Inflammatory Response ◽  
Tissue Integrity ◽  
Separation Force ◽  
The Impact ◽  
Rumen Epithelial Cells

Endotoxins play a crucial role in ruminant health due to their deleterious effects on animal health. The study aimed to evaluate whether LPS and LTA can induce an inflammatory response in rumen epithelial cells. For this purpose, epithelial cells isolated from rumen tissue (RECs) were stimulated with LPS and LTA for 1, 2, 4, and 24 h. Thereafter, the expression of selected genes of the LPS and LTA pathway and inflammatory response were evaluated. Furthermore, it was assessed whether LPS affects inflammatory response and structural integrity of claw explants. Therefore, claw explants were incubated with LPS for 4 h to assess the expression of selected genes and for 24 h to evaluate tissue integrity via separation force. LPS strongly affected the expression of genes related to inflammation (NFkB, TNF-α, IL1B, IL6, CXCL8, MMP9) in RECs. LTA induced a delayed and weaker inflammatory response than LPS. In claw explants, LPS affected tissue integrity, as there was a concentration-dependent decrease of separation force. Incubation time had a strong effect on inflammatory genes in claw explants. Our data suggest that endotoxins can induce a local inflammatory response in the rumen epithelium. Furthermore, translocation of LPS might negatively impact claw health.

Assessing the Preparedness of Healthcare Facilities for Disasters and Emergencies in Damghan, Iran

2021 ◽  
pp. 1-7
Author(s):  
Behrad Pourmohammadi ◽  
Ahad Heydari ◽  
Farin Fatemi ◽  
Ali Modarresi
Keyword(s):  
Health Care ◽  
Cross Sectional Study ◽  
Health Care Facilities ◽  
Mitigation Measures ◽  
Health Staff ◽  
Cross Sectional ◽  
Healthcare Facilities ◽  
Wide Range ◽  
Care Facilities ◽  
The Impact

Abstract Objectives: Iran is exposed to a wide range of natural and man-made hazards. Health-care facilities can play a significant role in providing life-saving measures in the minutes and hours immediately following the impact or exposure. The aim of this study was to determine the preparedness of health-care facilities in disasters and emergencies. Methods: This cross-sectional study was conducted in Damghan, Semnan Province, in 2019. The samples consisted of all the 11 health-care facilities located in Damghan County. A developed checklist was used to collect the data, including 272 questions in 4 sections: understanding threatening hazards, functional, structural, and nonstructural vulnerability of health-care facilities. The data were analyzed using SPSS 21. Results: The results revealed that the health-care facilities were exposed to 22 different natural and man-made hazards throughout the county. The total level of preparedness of the health-care centers under assessment was 45.8%. The average functional, structural, and nonstructural vulnerability was assessed at 49.3%, 31.6%, and 56.4%, respectively. Conclusions: Conducting mitigation measures is necessary for promoting the functional and structural preparedness. Disaster educational programs and exercises are recommended among the health staff in health-care facilities.

GEOPHYSICAL MONITORING: NEW OPPORTUNITIES TO PRESERVE ARCHITECTURAL MONUMENTS AND GREEN DESIGN IN URBAN AREAS

2020 ◽  
Author(s):  
Zakhar Slepak
Keyword(s):  
Urban Areas ◽  
Negative Impact ◽  
Technical Condition ◽  
Green Design ◽  
World Heritage Site ◽  
Mitigation Measures ◽  
Operating Life ◽  
Geophysical Monitoring ◽  
Railway Systems ◽  
Geological Processes

A new geophysical prospecting technique developed by the author was effectively applied for these purposes in 1994–2005 within the architectural complex of the Kazan Kremlin, a UNESCO World Heritage Site. The author has developed and successfully employed a unique gravity monitoring technique consisting in independent measurements at set points and at certain time intervals in the architectural complex of the Kazan Kremlin. The results of the geophysical monitoring and geodetic surveys conducted in open areas and inside architectural monuments offer new opportunities in preserving ancient buildings. Because geophysical monitoring can identify the negative impact of active geological processes on foundations of buildings, mitigation measures can be taken in timely manner. However, because the Kazan Kremlin is a state historical and architectural museum reserve, another objective is to maintain its exterior and renovate its green design. The above technology can also be used to analyze the technical condition of high-rise buildings, industrial facilities, underground railway systems and other structures, and significantly prolong their operating life.

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