Troubleshooting System Integrity

For fast track pipeline projects the need for costly installation vessels and sophisticated materials for rigid pipeline water injection systems, have made flexible pipelines a competitive alternative. They can be installed with less costly construction vessels, provide a competitive lead time and a corrosion resistant compliant material. Flexible pipelines have relative high axial stiffness and low non-linear bending stiffness which is a challenge to model correctly with FE for in-place analyses of pipelines. Whilst some FE programs can model the non-linear bending behaviour of a flexible pipeline at a given pressure, current FE tools do not include the effect of increased bending resistance as the system is pressurized. Therefore, a 3D FE model in ANSYS was developed to simulate the decoupled axial and nonlinear bending behaviour of a flexible, including the bend stiffening effect for increasing pressure. A description of the model is given in this paper. It will be demonstrated how the FE model can be used to simulate the 3D nonlinear catenary behaviour of an high pressure flexible pipeline tied into a manifold during pressurization. Due to high manifold hub loads during pressurization it is essential that such a model is capable of capturing all effects during pressurization to achieve an acceptable confidence level of the system integrity. It is also described how the FE model is used for upheaval buckling design, capturing non-linearities and load history effects that can reduce the conservatism in the design.

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Plant Foods Rich in Antioxidants and Human Cognition: A Systematic Review

Antioxidants ◽

10.3390/antiox10050714 ◽

2021 ◽

Vol 10 (5) ◽

pp. 714

Author(s):

Luciana Baroni ◽

Anna Rita Sarni ◽

Cristina Zuliani

Keyword(s):

Young Adult ◽

Human Cognition ◽

Cognitive Assessments ◽

Cross Sectional ◽

Cognitive Domains ◽

Plant Foods ◽

Beneficial Effects ◽

System Integrity ◽

Plant Antioxidants ◽

The Impact

Oxidative stress can compromise central nervous system integrity, thereby affecting cognitive ability. Consumption of plant foods rich in antioxidants could thereby protect cognition. We systematically reviewed the literature exploring the effects of antioxidant-rich plant foods on cognition. Thirty-one studies were included: 21 intervention, 4 cross-sectional (one with a cohort in prospective observation as well), and 6 prospective studies. Subjects belonged to various age classes (young, adult, and elderly). Some subjects examined were healthy, some had mild cognitive impairment (MCI), and some others were demented. Despite the different plant foods and the cognitive assessments used, the results can be summarized as follows: 7 studies reported a significant improvement in all cognitive domains examined; 19 found significant improvements only in some cognitive areas, or only for some food subsets; and 5 showed no significant improvement or no effectiveness. The impact of dietary plant antioxidants on cognition appears promising: most of the examined studies showed associations with significant beneficial effects on cognitive functions—in some cases global or only in some specific domains. There was typically an acute, preventive, or therapeutic effect in young, adult, and elderly people, whether they were healthy, demented, or affected by MCI. Their effects, however, are not attributable only to anti-oxidation.

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Remote attestation to dynamic system properties: Towards providing complete system integrity evidence

2009 IEEE/IFIP International Conference on Dependable Systems & Networks ◽

10.1109/dsn.2009.5270348 ◽

2009 ◽

Cited By ~ 58

Author(s):

Chongkyung Kil ◽

Emre C. Sezer ◽

Ahmed M. Azab ◽

Peng Ning ◽

Xiaolan Zhang

Keyword(s):

Dynamic System ◽

Complete System ◽

Remote Attestation ◽

System Integrity ◽

System Properties

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Protocol Design for Free Space Optical (FSO) Communication

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.738-739.1178 ◽

2015 ◽

Vol 738-739 ◽

pp. 1178-1184

Author(s):

Ru Hai Guo ◽

Chang Shun Liu ◽

Heng Kun Wang ◽

Jin Wu ◽

Jun Feng Chong

Keyword(s):

Free Space ◽

Data Stream ◽

Great Influence ◽

Exception Handling ◽

Free Space Optical ◽

System Integrity ◽

Serial Data ◽

Fpga Chip ◽

Signal Channel ◽

Wired Communication

A new transceiving protocol is designed for an FSO communication system, and it’s discussed from the transmitting protocol and the receiving protocol. Different from wired communication, a FSO system modulates the data on a narrow beam of laser transmitting through the free space or the atmosphere, and the protocol is optimized for terrestrial FSO links. Due to the complex composition and activity of the atmosphere, this signal channel brings in great influence on the transmitting laser in it. The function of the receiving protocol includes filtering and synchronizing the input serial data stream, paralleling the serial data stream, decoding the input data, error checking, and exception handling and interfacing the outer receiver with a parallel port. The transceiving protocol could be programmed into a single FPGA chip to improve system integrity and reduce the system cost. We also test the hardware platform and communication protocol and give the waveform. The experiment and Simulation prove that the protocol presented can work well at a certain bit rate scale.

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An Experimental Investigation of the Dynamics of a Loosely Supported Tube Array

Volume 4: Fluid-Structure Interaction ◽

10.1115/pvp2017-65898 ◽

2017 ◽

Cited By ~ 1

Author(s):

Amro Elhelaly ◽

Marwan Hassan ◽

Atef Mohany ◽

Soha Moussa

Keyword(s):

Experimental Investigation ◽

Impact Force ◽

Cross Flow ◽

Open Loop ◽

Diameter Ratio ◽

Force Level ◽

Steam Generators ◽

Flow Induced Vibration ◽

System Integrity ◽

Tube Bundles

The integrity of tube bundles is very important especially when dealing with high-risk applications such as nuclear steam generators. A major issue to system integrity is the flow-induced vibration (FIV). FIV is manifested through several mechanisms including the most severe mechanism; fluidelastic instability (FEI). Tube vibration can be constrained by using tube supports. However, clearances between the tube and their support are required to allow for thermal expansion and for other manufacturing considerations. The clearance between tubes may allow frequent impact and friction between tube and support. This in turn may cause fatigue and wear at support and potential for catastrophic tube failure. This study aims to investigate the dynamics of loosely supported tube array subjected to cross-flow. The work is performed experimentally in an open-loop wind tunnel to address this issue. A loosely-supported single flexible tube in both triangle and square arrays subjected to cross-flow with a pitch-to-diameter ratio of 1.5 and 1.733, respectively were considered. The effect of the flow approach angle, as well as the support clearance on the tube response, are investigated. In addition, the parameters that affect tube wear such as impact force level are presented.

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Mechanical Qualification of Dynamic Deep Water Power Cable

Volume 4: Pipeline and Riser Technology ◽

10.1115/omae2011-49945 ◽

2011 ◽

Cited By ~ 1

Author(s):

Roger Slora ◽

Stian Karlsen ◽

Per Arne Osborg

Keyword(s):

Water Depth ◽

Deep Water ◽

Failure Modes ◽

Electrical Power ◽

Oil And Gas Industry ◽

Electrical Heating ◽

Power Cable ◽

Water Power ◽

System Integrity ◽

Water Depths

There is an increasing demand for subsea electrical power transmission in the oil- and gas industry. Electrical power is mainly required for subsea pumps, compressors and for direct electrical heating of pipelines. The majority of subsea processing equipment is installed at water depths less than 1000 meters. However, projects located offshore Africa, Brazil and in the Gulf of Mexico are reported to be in water depths down to 3000 meters. Hence, Nexans initiated a development programme to qualify a dynamic deep water power cable. The qualification programme was based on DNV-RP-A203. An overall project plan, consisting of feasibility study, concept selection and pre-engineering was outlined as defined in DNV-OSS-401. An armoured three-phase power cable concept assumed suspended from a semi-submersible vessel at 3000 m water depth was selected as qualification basis. As proven cable technology was selected, the overall qualification scope is classified as class 2 according to DNV-RP-A203. Presumed high conductor stress at 3000 m water depth made basis for the identified failure modes. An optimised prototype cable, with the aim of reducing the failure mode risks, was designed based on extensive testing and analyses of various test cables. Analyses confirmed that the prototype cable will withstand the extreme loads and fatigue damage during a service life of 30 years with good margins. The system integrity, consisting of prototype cable and end terminations, was verified by means of tension tests. The electrical integrity was intact after tensioning to 2040 kN, which corresponds to 13 000 m static water depth. A full scale flex test of the prototype cable verified the extreme and fatigue analyses. Hence, the prototype cable is qualified for 3000 m water depth.

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