Quantitative safety assessment of pressure control failure in a deep underground large scale cryogenic installation

2016 ◽  
Vol 151 ◽  
pp. 60-75 ◽  
Author(s):  
E.C. Marcoulaki ◽  
A.G. Venetsanos ◽  
I.A. Papazoglou
Keyword(s):  
Safety Assessment ◽  
Large Scale ◽  
Pressure Control ◽  
Control Failure ◽  
Deep Underground ◽  
Quantitative Safety Assessment

scholarly journals Development and Validation of a Post-Earthquake Safety Assessment System for High-Rise Buildings Using Acceleration Measurements

Mathematics ◽  
2021 ◽  
Vol 9 (15) ◽  
pp. 1758
Author(s):  
Koji Tsuchimoto ◽  
Yasutaka Narazaki ◽  
Billie F. Spencer
Keyword(s):  
Safety Assessment ◽  
Large Scale ◽  
Model Updating ◽  
Safety Evaluation ◽  
Assessment System ◽  
Shaking Table ◽  
Structural Safety ◽  
High Rise ◽  
Steel Building ◽  
Earthquake Safety

After a major seismic event, structural safety inspections by qualified experts are required prior to reoccupying a building and resuming operation. Such manual inspections are generally performed by teams of two or more experts and are time consuming, labor intensive, subjective in nature, and potentially put the lives of the inspectors in danger. The authors reported previously on the system for a rapid post-earthquake safety assessment of buildings using sparse acceleration data. The proposed framework was demonstrated using simulation of a five-story steel building modeled with three-dimensional nonlinear analysis subjected to historical earthquakes. The results confirmed the potential of the proposed approach for rapid safety evaluation of buildings after seismic events. However, experimental validation on large-scale structures is required prior to field implementation. Moreover, an extension to the assessment of high-rise buildings, such as those commonly used for residences and offices in modern cities, is needed. To this end, a 1/3-scale 18-story experimental steel building tested on the shaking table at E-Defense in Japan is considered. The importance of online model updating of the linear building model used to calculate the Damage Sensitive Features (DSFs) during the operation is also discussed. Experimental results confirm the efficacy of the proposed approach for rapid post-earthquake safety evaluation for high-rise buildings. Finally, a cost-benefit analysis with respect to the number of sensors used is presented.

Mathematical Approaches in Functional Safety Assessment for E/E/PE Safety-Related Software

2021 ◽  
pp. 2150043
Author(s):  
Shinji Inoue ◽  
Takaji Fujiwara ◽  
Shigeru Yamada
Keyword(s):  
Software Reliability ◽  
Safety Assessment ◽  
Assessment Method ◽  
Functional Safety ◽  
Reliability Modeling ◽  
Software Failure ◽  
Safety Integrity Level ◽  
Iec 61508 ◽  
Systematic Failure ◽  
Quantitative Safety Assessment

Safety integrity level (SIL)-based functional safety assessment is widely required in designing safety functions and checking their validity of electrical/electronic/programmable electronic (E/E/PE) safety-related systems after being issued IEC 61508 in 2010. For the hardware of E/E/PE safety-related systems, quantitative functional safety assessment based on target failure measures is needed for deciding or allocating the level of SIL. On the other hand, IEC 61508 does not provide any quantitative safety assessment method for allocating SIL for the software of E/E/PE safety-related systems because the software failure is treated as a systematic failure in IEC 61508. We discuss the needfulness of quantitative safety assessment for software of E/E/PE safety-related systems and propose mathematical fundamentals for conducting quantitative SIL-based safety assessment for the software of E/E/PE safety-related systems by applying the notion of software reliability modeling and assessment technologies. We show numerical examples for explaining how to use our approaches.

scholarly journals Large-Scale Molecular Dynamics Simulations Reveal New Insights Into the Phase Transition Mechanisms in MIL-53(Al)

2021 ◽  
Vol 9 ◽  
Author(s):  
Sander Vandenhaute ◽  
Sven M. J. Rogge ◽  
Veronique Van Speybroeck
Keyword(s):  
Large Scale ◽  
Pressure Control ◽  
Layer By Layer ◽  
Major Step ◽  
Transition Mechanism ◽  
External Pressures ◽  
Pressure Regime ◽  
Dynamics Simulations ◽  
Experimental Crystal ◽  
External Stimuli

Soft porous crystals have the ability to undergo large structural transformations upon exposure to external stimuli while maintaining their long-range structural order, and the size of the crystal plays an important role in this flexible behavior. Computational modeling has the potential to unravel mechanistic details of these phase transitions, provided that the models are representative for experimental crystal sizes and allow for spatially disordered phenomena to occur. Here, we take a major step forward and enable simulations of metal-organic frameworks containing more than a million atoms. This is achieved by exploiting the massive parallelism of state-of-the-art GPUs using the OpenMM software package, for which we developed a new pressure control algorithm that allows for fully anisotropic unit cell fluctuations. As a proof of concept, we study the transition mechanism in MIL-53(Al) under various external pressures. In the lower pressure regime, a layer-by-layer mechanism is observed, while at higher pressures, the transition is initiated at discrete nucleation points and temporarily induces various domains in both the open and closed pore phases. The presented workflow opens the possibility to deduce transition mechanism diagrams for soft porous crystals in terms of the crystal size and the strength of the external stimulus.

Safety assessment method of steel protective structure against large-scale debris flow

2021 ◽  
pp. 204141962110595
Author(s):  
Hiroshi Kokuryo ◽  
Toshiyuki Horiguchi ◽  
Nobutaka Ishikawa
Keyword(s):  
Debris Flow ◽  
Safety Assessment ◽  
Large Scale ◽  
Assessment Method ◽  
Load Level ◽  
Energy Constant ◽  
Level Ii ◽  
Load Carrying ◽  
Torrential Rainfall ◽  
Protective Structures

Recently, steel pipe open type protective structures (steel open dams) have been damaged because of large-scale debris flow resulting from torrential rainfall based on abnormal climate. This article proposes a safety assessment method for the load-carrying capacity of a steel open dam against large-scale debris flow load (level II load) using the energy constant law. First, the safety assessment method of steel open dams is proposed that the ultimate strength must be larger than the required strength against the level II load, which is determined by using the energy constant law. Second, the load-carrying capacities of three types of steel open dams with different structural shapes against the front and eccentric debris flow loadings are investigated by a push-over analysis. Finally, the safety assessments on load-carrying capacities against the front and eccentric debris flow loading are confirmed and the strength reduction by the eccentric loading is examined for three steel open dams.

scholarly journals Evaluation of Shrimp Waste Valorization Combining Computer-Aided Simulation and Numerical Descriptive Inherent Safety Technique (NuDIST)

2020 ◽  
Vol 10 (15) ◽  
pp. 5339 ◽  
Author(s):  
Antonio Zuorro ◽  
Daylisney Cassiani-Cassiani ◽  
Demmy A. Meza-González ◽  
Kariana Andrea Moreno-Sader ◽  
Ángel Darío González-Delgado
Keyword(s):  
Safety Assessment ◽  
Large Scale ◽  
Scale Production ◽  
Heat Of Reaction ◽  
Inherent Safety ◽  
Process Safety ◽  
Waste Valorization ◽  
Large Scale Production ◽  
Safety Technique ◽  
Shrimp Wastes

Nowadays, inherently safer designs are considered as key priorities to prevent or mitigate serious incidents with devastating consequences. The need for process safety assessment during early design phases has motivated the development of several contributions related to computer-aided assessment methodologies to measure the inherent safety of chemical processes. In this work, the large-scale production of chitosan from shrimp wastes was evaluated from a process safety point of view using the numerical descriptive inherent safety technique (NuDIST). To this end, simulation of the chitosan production was performed using Aspen Plus ® to obtain extended mass and energy balances. The assessment of all the chemicals involved within the process was carried out for the following safety parameters: explosivity (EXP), flammability (FL), and toxicity (TOX). The safety assessment of the process included the parameters of temperature (T), pressure (P), and heat of reaction (HR). The maximum chemical safety score was estimated in 171.01 with ethanol as the main contributor to the parameters of explosivity and flammability. The score associated with operating data was calculated at 209.20 and heat of reaction reported to be the most affecting parameter. The NuDIST score was estimated at 380.20. This NuDIST value revealed the low hazards associated with the handling of substances such as shrimp wastes, chitosan, and water, as well as the non-extreme temperature and pressure conditions. In general, the large-scale production of chitosan from shrimp shells was shown to be an inherently safe alternative of waste valorization.

scholarly journals Adaptive water distribution networks with dynamically reconfigurable topology

2014 ◽  
Vol 16 (6) ◽  
pp. 1280-1301 ◽  
Author(s):  
Robert Wright ◽  
Ivan Stoianov ◽  
Panos Parpas ◽  
Kevin Henderson ◽  
John King
Keyword(s):  
High Speed ◽  
Water Distribution ◽  
Large Scale ◽  
Pressure Control ◽  
Distribution Networks ◽  
Water Distribution Networks ◽  
Incident Management ◽  
Major Drawback ◽  
Dynamically Reconfigurable ◽  
Minimum Night Flow

This paper presents a novel concept of adaptive water distribution networks with dynamically reconfigurable topology for optimal pressure control, leakage management and improved system resilience. The implementation of District Meter Areas (DMAs) has greatly assisted water utilities in reducing leakage. DMAs segregate water networks into small areas, the flow in and out of each area is monitored and thresholds are derived from the minimum night flow to trigger the leak localization. A major drawback of the DMA approach is the reduced redundancy in network connectivity which has a severe impact on network resilience, incident management and water quality deterioration. The presented approach for adaptively reconfigurable networks integrates the benefits of DMAs for managing leakage with the advantages of large-scale looped networks for increased redundancy in connectivity, reliability and resilience. Self-powered multi-function network controllers are designed and integrated with novel telemetry tools for high-speed time-synchronized monitoring of the dynamic hydraulic conditions. A computationally efficient and robust optimization method based on sequential convex programming is developed and applied for the dynamic topology reconfiguration and pressure control of water distribution networks. An investigation is carried out using an operational network to evaluate the implementation and benefits of the proposed method.

Numerical Analysis of a Large-Scale Hydraulic Wind Farm With Integrated Hydraulic Energy Storage

2016 ◽  
Author(s):  
Daniel Buhagiar ◽  
Tonio Sant
Keyword(s):  
Wind Turbine ◽  
Output Power ◽  
Large Scale ◽  
Wind Farm ◽  
Wind Farms ◽  
Strong Relationship ◽  
Pressure Control ◽  
Open Loop ◽  
Offshore Wind ◽  
Pipeline Network

Offshore wind farms are presently facing numerous technical challenges that are affecting their viability. High failure rates of expensive nacelle-based electronics and gearboxes are particularly problematic. On-going research is investigating the possibility of shifting to a seawater-based hydraulic power transmission, whereby wind turbines pressurise seawater that is transmitted across a high-pressure pipeline network. A 9-turbine hydraulic wind farm with three different configurations is simulated in the present work and a previously developed method for open-loop pressure control of a single turbine has been adapted for this multiple-turbine scenario. A conceptual quasi-constant-pressure accumulator is also included in the model. This system is directly integrated within each hydraulic wind turbine and it allows the output power from the wind farm to be scheduled on an hourly basis. The shift in control methodology when integrating storage is illustrated in the present work. Simulation results indicate a strong relationship between hydraulic performance attributes and the specific wind turbine array layout. The beneficial effects of storage can also be observed, particularly in smoothing the output power and rendering it more useable. Finally, the energy yields from 24-hour simulations of the 9-turbine wind farms are calculated. Integrated storage leads to a slight increase in yield since it eliminates bursts of high flow, which induce higher frictional losses in the pipeline network.

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