Relevant bibliographies by topics / 1-safe nets

Academic literature on the topic '1-safe nets'

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Published: 9 March 2023
Last updated: 10 March 2023

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Journal articles on the topic "1-safe nets"

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Cheng, Allan, Javier Esparza, and Jens Palsberg. "Complexity results for 1-safe nets." Theoretical Computer Science 147, no. 1-2 (August 1995): 117–36. http://dx.doi.org/10.1016/0304-3975(94)00231-7.

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Chalopin, Jérémie, and Victor Chepoi. "1-Safe Petri Nets and Special Cube Complexes." ACM Transactions on Computational Logic 20, no. 3 (July 16, 2019): 1–49. http://dx.doi.org/10.1145/3322095.

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Marchese, Ugo, Martin Gaillard, Anna Pellat, Stylianos Tzedakis, Einas Abou Ali, Anthony Dohan, Maxime Barat, Philippe Soyer, David Fuks, and Romain Coriat. "Multimodal Management of Grade 1 and 2 Pancreatic Neuroendocrine Tumors." Cancers 14, no. 2 (January 15, 2022): 433. http://dx.doi.org/10.3390/cancers14020433.

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Pancreatic neuroendocrine tumors (p-NETs) are rare tumors with a recent growing incidence. In the 2017 WHO classification, p-NETs are classified into well-differentiated (i.e., p-NETs grade 1 to 3) and poorly differentiated neuroendocrine carcinomas (i.e., p-NECs). P-NETs G1 and G2 are often non-functioning tumors, of which the prognosis depends on the metastatic status. In the localized setting, p-NETs should be surgically managed, as no benefit for adjuvant chemotherapy has been demonstrated. Parenchymal sparing resection, including both duodenum and pancreas, are safe procedures in selected patients with reduced endocrine and exocrine long-term dysfunction. When the p-NET is benign or borderline malignant, this surgical option is associated with low rates of severe postoperative morbidity and in-hospital mortality. This narrative review offers comments, tips, and tricks from reviewing the available literature on these different options in order to clarify their indications. We also sum up the overall current data on p-NETs G1 and G2 management.
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Abbes, Samy. "Toward uniform random generation in 1-safe Petri nets." Electronic Notes in Discrete Mathematics 59 (June 2017): 3–17. http://dx.doi.org/10.1016/j.endm.2017.05.002.

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Mishra, P. K. "Lower and upper bounds of shortest paths in reachability graphs." International Journal of Mathematics and Mathematical Sciences 2004, no. 57 (2004): 3023–36. http://dx.doi.org/10.1155/s0161171204403378.

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We prove the following property for safe marked graphs, safe conflict-free Petri nets, and live and safe extended free-choice Petri nets. We prove the following three results. If the Petri net is a marked graph, then the length of the shortest path is at most(|T|−1)⋅|T|/2. If the Petri net is conflict free, then the length of the shortest path is at most(|T|+1)⋅|T|/2. If the petrinet is live and extended free choice, then the length of the shortest path is at most|T|⋅|T+1|⋅|T+2|/6, whereTis the set of transitions of the net.
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Męski, Artur, Wojciech Penczek, and Agata Półrola. "BDD-based Bounded Model Checking for Temporal Properties of 1-Safe Petri Nets." Fundamenta Informaticae 109, no. 3 (2011): 305–21. http://dx.doi.org/10.3233/fi-2011-513.

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Singh, Gajendra Pratap, Sujit Kumar Singh, and Madhuri Jha. "Existence of Forbidden Digraphs for Crisp Boolean Petri Nets." International Journal of Mathematical, Engineering and Management Sciences 5, no. 1 (November 1, 2019): 83–95. http://dx.doi.org/10.33889/ijmems.2020.5.1.008.

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Boolean Petri net (BPN) and Crisp Boolean Petri net (CBPN) is a well-studied graph model since 2010 which has several applications in mathematical modeling of complex or tricky networks. Modeling any network with Petri net which can generate binary numbers as marking vectors in its reachability tree is still has much uses. In CBPN with a minimum number of transition and minimum number of steps of reachability tree, minimal execution time to run the machine has not been noted till date, thus it’s necessary to sort out this problem. Possibly it may occur due to some forbidden structure which hinders any 1-safe Petri net to be a CBPN. In this paper, we present some forbidden digraphs whose presence interrupts the generation of binary n-vectors exactly once. Any 1-safe Petri net is not a CBPN if it contains any of the subnet induced to the four forbidden structures discussed in this paper.
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Hawa, Fadi, Zeyad Sako, Than Nguyen, Andrew T. Catanzaro, Eugene Zolotarevsky, Angela N. Bartley, and Naresh T. Gunaratnam. "The band and slough technique is effective for management of diminutive type 1 gastric and duodenal neuroendocrine tumors." Endoscopy International Open 08, no. 06 (May 25, 2020): E717—E721. http://dx.doi.org/10.1055/a-1119-6698.

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Abstract Background and study aims Endoscopic resection is recommended as initial treatment for early-stage gastric and duodenal neuroendocrine tumors (G-NETs and D-NETs). However, it can cause serious adverse events. We aimed to evaluate the efficacy and safety of the band and slough (BAS) technique as a novel and less aggressive endoscopic therapy for management of such tumors.Four patients, three diagnosed with < 10-mm D-NET and one with 10-mm type I G-NET, were treated with the BAS technique without endoscopic resection. Initial follow-up endoscopy at 3 months was done to assess for residual tumor. Subsequent endoscopic surveillance was performed. After one session of banding, all patients achieved complete remission at 3-month follow-up. No tumor recurrence was detected on repeat biopsy at 12-month surveillance endoscopy. None of the patients developed any adverse events including bleeding or perforation.The BAS technique may prove to be a safe and effective endoscopic therapy for diminutive, non-metastatic type 1 G-NETs and D-NETs. Studies of larger scale and longer follow-up periods are needed to corroborate these findings.
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Czaja, Ludwik. "Extensions of Elementary Cause-Effect Structures." Fundamenta Informaticae 179, no. 2 (March 10, 2021): 93–111. http://dx.doi.org/10.3233/fi-2021-2016.

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Cause-effect structures are objects of a formal system devised for modeling, testing and verifying properties of tasks, where parallel execution of actions is the most characteristic feature. This is an algebraic system called a quasi-semiring. In this paper elementary cause-effect structures, a system behaviourally equivalent to 1-safe Petri nets, are extended by the following features: weighted edges, multi-valued nodes having capacities (counterpart of place/transition Petri nets), inhibitors and a model of time. The extensions are accomplished by modifying the notion of state and semantics, but leaving unchanged structure of the quasi-semiring expressions.
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Heljanko, Keijo. "Using Logic Programs with Stable Model Semantics to Solve Deadlock and Reachability Problems for 1-Safe Petri Nets." Fundamenta Informaticae 37, no. 3 (1999): 247–68. http://dx.doi.org/10.3233/fi-1999-37304.

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Dissertations / Theses on the topic "1-safe nets"

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MASCHERONI, MARCO. "Hypernets: a class of hierarchical petri nets." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2011. http://hdl.handle.net/10281/19228.

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The interest of this thesis is on modeling systems of mobile agents, systems composed of several open and autonomous components which can interact and move inside one or more environments. Several proposal for modeling mobility have been introduced. They can be roughly divided in two categories: Petri net based formalisms, and process algebra based formalisms. In this thesis, Petri net formalisms will mostly be considered, with particular care to formalisms which use the nets-within-nets paradigm. In models compliant to this paradigm the tokens of a Petri net can be nets themselves. Since systems of mobile agents exhibit a nesting structure, it seems natural to use this paradigm. In particular, the focus of this dissertation is on the hypernet model, whose main characteristic is that it has a limited state space, characteristic that make it suitable to be analyzed using well known Petri net techniques. The thesis topics range from theoretical aspects of the model to more practical issues. From a theoretical point of view an extension of the model is introduced. It is proved that this extension preserves all the good properties of the basic model. It is also studied how to apply the well known unfolding technique to this model. From a practical point of view is is shown how the nets-within nets paradigm can be used to model systems based on the Grid infrastructure. Moreover, a tool which allow to draw and to analyze an hypernet is discussed.
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Book chapters on the topic "1-safe nets"

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Best, Eike, and Harro Wimmel. "Reducing k-Safe Petri Nets to Pomset-Equivalent 1-Safe Petri Nets." In Lecture Notes in Computer Science, 63–82. Berlin, Heidelberg: Springer Berlin Heidelberg, 2000. http://dx.doi.org/10.1007/3-540-44988-4_6.

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Cheng, Allan, Javier Esparza, and Jens Palsberg. "Complexity results for 1-safe nets." In Lecture Notes in Computer Science, 326–37. Berlin, Heidelberg: Springer Berlin Heidelberg, 1993. http://dx.doi.org/10.1007/3-540-57529-4_66.

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Lodaya, Kamal, D. Ranganayakulu, and K. Rangarajan. "Hierarchical Structure of 1-Safe Petri Nets." In Advances in Computing Science – ASIAN 2003. Progamming Languages and Distributed Computation Programming Languages and Distributed Computation, 173–87. Berlin, Heidelberg: Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-540-40965-6_12.

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Praveen, M., and Kamal Lodaya. "Parameterized Complexity Results for 1-safe Petri Nets." In CONCUR 2011 – Concurrency Theory, 358–72. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-23217-6_24.

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Heljanko, Keijo. "Using Logic Programs with Stable Model Semantics to Solve Deadlock and Reachability Problems for 1-Safe Petri Nets." In Tools and Algorithms for the Construction and Analysis of Systems, 240–54. Berlin, Heidelberg: Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/3-540-49059-0_17.

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Sharkey, Amanda J. C., Noel E. Sharkey, and Gopinath O. Chandroth. "Neural Nets and Diversity." In Safe Comp 95, 375–89. London: Springer London, 1995. http://dx.doi.org/10.1007/978-1-4471-3054-3_25.

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Górski, Janusz, Jan Magott, and Andrzej Wardziński. "Modeling Fault Trees Using Petri Nets." In Safe Comp 95, 90–100. London: Springer London, 1995. http://dx.doi.org/10.1007/978-1-4471-3054-3_7.

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Shumba, Jenny, Symphorosa Rembe, Toyin Adewumi, Henry Chinhara, Sibangani Shumba, and Cosmas Maphosa. "Maintaining Safety Nets and Peace for Children and Youth at Risk." In Cultivating a Culture of Nonviolence in Early Childhood Development Centers and Schools, 82–100. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-7476-7.ch005.

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A safe school environment is conducive for learning at all levels of education. However, schools sometimes enroll children who are generally at risk due to various factors. The chapter discussed how schools and early childhood centers (ECD) can maintain safety and peace for children and youths in their care. By virtue of their age, young children are a population at risk as they depend on adults for their sustenance. A safe environment for children entails physical safety, mental health, social security, and nutrition. The chapter focused on safety nets, strategies/models of maintaining safety, peace projects for children and youths, description of children at risk, stakeholders in maintaining safety, risk factors affecting children and youths. It presents Bronfenbrenner's ecological systems theory that informs the role of systems surrounding the child in maintaining safety nets and peace. The chapter proffers a model that can be adopted to maintain safety nets and peace.
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Lemcke, Jens, Andreas Friesen, and Tirdad Rahmani. "Validating Component-Based Implementations of Business Processes." In Electronic Business Interoperability, 124–51. IGI Global, 2011. http://dx.doi.org/10.4018/978-1-60960-485-1.ch007.

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This chapter provides a formal specification of non-atomic, relaxed action refinement suited for component-based business process engineering. Engineering a business process involves multiple process models created by different people on different levels of abstractions. Keeping the models consistent during the engineering procedure—refinement validation—is one objective of this chapter. In component-based software engineering, the lowest abstraction of a business process is mapped on existing components that have a description of their behaviors. Checking the consistency of process and component behavior—grounding validation—is the second objective. Both refinement and grounding validation increase the robustness of business process implementations and the productivity of process engineers. Technically, the specification given in this chapter is in terms of deadlock analysis in safe Petri nets. The evaluation of this straight-forward implementation underlines the exponential complexity of deadlock analysis in safe Petri nets. For use cases with more than 30 activities per process or heavy parallelism, optimized implementations are needed.
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Ciufudean, Calin. "A New Formalism for Diagnosis and Safe Development of Information Systems." In Advances in IT Personnel and Project Management, 206–28. IGI Global, 2016. http://dx.doi.org/10.4018/978-1-4666-9688-4.ch012.

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Failure diagnosis in large and complex information systems (LCIS) is a critical task due to respect the safe development of these systems. A discrete event system (DES) approach to the problem of failure diagnosis of LCIS is presented in this chapter. A classic solution to solve DES's diagnosis is a stochastic Petri nets. Unfortunately, the solution of a stochastic Petri net is severely restricted by the size of its underlying Markov chain. On the other hand, it has been shown that foraging behavior of ant colonies can give rise to the shortest path, which will reduce the state explosion of stochastic Petri net. Therefore, a new model of stochastic Petri net, based on foraging behavior of real ant colonies is introduced in this paper. This model can contribute to the diagnosis, the performance analysis and design of information systems.
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Conference papers on the topic "1-safe nets"

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Jourdan, Guy-Vincent, and Gregor V. Bochmann. "On Testing 1-Safe Petri Nets." In 2009 Third IEEE International Symposium on Theoretical Aspects of Software Engineering (TASE). IEEE, 2009. http://dx.doi.org/10.1109/tase.2009.20.

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He, Kevin X., and Michael D. Lemmon. "Validation of liveness for 1-safe hybrid Petri nets using network unfolding." In 1999 European Control Conference (ECC). IEEE, 1999. http://dx.doi.org/10.23919/ecc.1999.7099843.

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Kansal, Sangita, Gajendra Pratap Singh, and Mukti Acharya. "A Disconnected 1-Safe Petri Net Whose Reachability Tree Is Homomorphic to a Complete Boolean Lattice." In 2011 International Conference on Process Automation, Control and Computing (PACC). IEEE, 2011. http://dx.doi.org/10.1109/pacc.2011.5979037.

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Young, Garry G., and Jason Remer. "Subsequent License Renewal in the U.S." In ASME 2015 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/pvp2015-45586.

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As of January 2015, the NRC has renewed the operating licenses for 75 nuclear units, allowing for up to 60 years of safe operation. In addition, the NRC has license renewal applications under review for 19 units and 5 additional units have announced plans to submit applications over the next few years. This brings the total of renewed licenses and plans for renewal to almost 100% of the operating nuclear units in the U.S. At the end of 2014 there were 38 nuclear plants that had operated for more than 40 years and are eligible to seek a second license renewal (or 38% of the operating units). [1] Although some nuclear plant owners have shutdown operation recently and others have announced plans to shutdown before reaching 60 years, the majority are keeping the option open for long term operation beyond 60 years. NRC and the U.S. nuclear industry have made significant progress in preparing the way for second license renewal applications. For example, in October 2014, 7 nuclear units were identified as the leading candidates for subsequent license renewal in a New York Times news article. This paper presents the status of the issues being addressed for possible applications for second license renewals for up to 80 years of operation.
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Al Ali, Eman, Ravi Srinivas, Jawwad Kaleem, Ganank Srivastava, and Mostafa Shehata. "A Multi-Layered Strategy to Manage Foaming in Ultra-Sour Gas Sweetening Units." In ADIPEC. SPE, 2022. http://dx.doi.org/10.2118/211268-ms.

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Abstract Foaming is a major operational occurrence seen in gas sweetening units; causing production losses, off-spec product, solvent losses, equipment corrosion and excessive consumption of anti- foam chemicals. Foaming can therefore shutdown an entire unit if mismanaged. This paper details a multi-layered bulletproof strategy to manage foaming while operating and designing ultra-sour gas sweetening units. Process simulation models of an operational amine unit at ADNOC Sour Gas (ASG) were built to showcase the positive impacts of each of these recommendations on the performance of the unit. This multi-pronged guideline that adds a safety-net around the upstream separation equipment, sour feed gas, lean amine, and absorber include: (1) Internal modifications to the upstream feed gas separator; (2) Fail-safe design practice around feed separator; (3) Recalculation & modification to the conventional 5 degC temperature approach rule for the lean solvent & (4) Robust differential pressure measurement across absorber. The above recommendations demonstrated a CAPEX and OPEX saving of US$ 25 MM and US$ 0.6 MMPA respectively to ASG. In addition, reduction in process upsets and pressure drops in the gas circuit generated production related revenues of &gt; US$ 2 million/yr.
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Hardy, Robert, and Neha Vijh. "Accelerating the Path to Net Zero with Blue Hydrogen: A Route to Achieving Best-In-Class Environmental Performance and Economics." In ADIPEC. SPE, 2022. http://dx.doi.org/10.2118/210888-ms.

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Abstract Most major economies around the world have committed to meeting ambitious net zero targets by 2050. As a versatile, clean and safe energy carrier, hydrogen is expected to play a crucial role in the transition to net zero. Large-scale, economic production of low carbon hydrogen is essential for the mass decarbonisation process, and this is especially true for hard-to-abate sectors such as the steel, cement and chemical industries, as well as dispatchable power, domestic heating and transport. To accelerate the energy transition, Johnson Matthey (JM) has developed a unique carbon capture and storage (CCS)-enabled hydrogen production process that economically delivers very low carbon intensity hydrogen, commonly known as ‘blue’ hydrogen. The flowsheet combines a gas-heated reformer (GHR) and autothermal reformer (ATR), and provides a more energy efficient process than both conventional steam methane reforming (SMR) and flowsheets that deploy a stand-alone ATR, ultimately resulting in a higher hydrogen yield and reducing natural gas consumption. JM's GHR-ATR blue hydrogen technology makes decarbonisation via CCS easier and cheaper than using an SMR. By delivering a CO2 capture rate of over 95%, the technology provides significant benefits compared with SMR and alternative ATR technologies. Compared with conventional SMR, JM's GHR-ATR blue hydrogen technology demonstrates: Natural gas consumption – 10% lowerCO2 produced – 10% lessCapital cost for the CO2 capture system – 75% lower Use of JM's unique GHR-ATR blue hydrogen technology will future-proof and de-risk projects by minimising the impact of rising feedstock, CO2 transmission and storage costs, as well as potential governmental schemes for carbon taxation. This process will enable hard-to-abate sectors to reduce Scope 1 and Scope 2 emissions by decarbonising their operations, accelerate the energy transition by producing clean hydrogen for consumers, ensure the viability of the plant for the future, and demonstrate commitment to sustainability. JM's GHR-ATR blue hydrogen technology has been selected for deployment by HyNet North-West, the United Kingdom's first low carbon hydrogen plant. The 300 MW plant is expected to be built in the UK in 2026 (pending the final investment decision), and will provide hydrogen to industrial and eventually domestic customers.
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Chevalier, Marc, Peter James, and Nicholas Underwood. "Establishing AMR Structural Integrity Codes and Standards for UK GDA (EASICS): Overview of Activities to Provide Guidance for the UK Generic Design Assessment Process for High Temperature Advanced Modular Reactors." In ASME 2020 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/pvp2020-21721.

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Abstract The UK government has committed to achieving “net-zero” carbon emissions by 2050. Nuclear power is expected to play an important role in this undertaking. Therefore delivering new safe and cost efficient nuclear technologies is seen as essential by both the UK Government and industry. Included in these new nuclear technology are small modular Generation VI reactors, referred to as Advanced Modular Reactors (AMRs). It has previously been identified that there is currently no clear route to demonstrating the structural integrity of such high temperature reactors to the UK regulator, with known short falls in the available codes and standards. Therefore EDF, Rolls-Royce and the National Nuclear Laboratory have collaborated to deliver the “Establishing AMR Structural Integrity Codes and Standards for UK GDA” (EASICS) project (part funded by the UK Government). This project looks to provide guidance on how existing design codes (such as RCC-MRx and ASME Section III Division 5) and assessment methodologies (such as R5 and R6) can be used to demonstrate the integrity of design within a UK regulatory framework. In addition, the project looks to make technological advancements in a number of key areas to address some known shortfalls in the available design codes and standards. These include 1) probabilistic design, 2) thin section defect tolerance and 3) creep-fatigue behaviour. This paper provides a summary of the current findings and an overview of the planned activities regarding Codes and Standards aspects of the project. This includes a review of the challenges within a UK regulatory framework for high temperature plant, key differences between available high temperature design codes and assessment methodologies, operational experience of high temperature nuclear reactors and key shortfalls in the available codes and standards. It will finally provide a description of what the final EASICS guidance document will be expected to contain when delivered in 2021.
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Alizadeh, Hassan, Simon J. Lewis, Christopher Gill, S. Hossain, David J. Smith, and Christopher E. Truman. "Measurement and Prediction of the Residual Stress Field in an Autogenously Welded Stainless Steel Plate." In ASME 2008 Pressure Vessels and Piping Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/pvp2008-61341.

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There has been a concerted effort over recent years to develop and refine finite element models of welds in order to predict residual stresses. These residual stresses are required to ever improved accuracies in order to provide continued confidence in the safe operation of ageing plant. Not only have computing hardware and software developed at a rapid rate, but guidelines for weld modelling ‘best practice’ have started to be documented. In order to validate and verify weld modelling procedures, test specimens are required which may be subjected to a suite of residual stress measurement techniques in order to allow comparison and ‘benchmarking’ of the numerical predictions. An abundance of such test specimens have been developed over the last few years. These are typically studied via large multi-national ‘round robins’ and results used to fine tune methodologies. A specific example is the NeT ‘bead on plate’ specimen [1, 2] which considered a single weld bead on an austenitic stainless steel plate. Whilst the major thrust worldwide now is to fabricate and study test specimens more representative of real plant, by considering larger specimens, many weld passes, different materials (including ferritic steels and their associated phase change during welding), the research presented in this paper considers an even simpler test specimen. Thus, an autogenous (no filler material) weld on a stainless steel plate is considered. There were two principal motivations for this work. Firstly, numerical and experimental results were required to validate analytical models of welding induced residual stresses. These analytical models [3] are currently under development but, to date, have been formulated only for parent material. Secondly, the lessons learned on weld modelling from previous studies were desired to be tested on the simplest test specimen available.
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Tatli, Emre, Sung Jin Lee, Jun Liao, and Paolo Ferroni. "Assessment of Passive Cooling Capability of the Westinghouse Lead Fast Reactor Under Station Blackout Conditions." In 2022 29th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/icone29-91821.

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Abstract Westinghouse is developing its next generation of high-capacity nuclear power plants with the Westinghouse Lead-cooled Fast Reactor (LFR) (Ref. 1). The Westinghouse LFR is a pool-type 950 MWt (∼450 MWe Net) passively safe modular construction plant that contains all the primary system components within the reactor vessel, including the reactor coolant pumps (RCPs) and the primary heat exchangers (PHEs). Similar to the Westinghouse AP1000® Pressurized Water Reactor design, the Westinghouse LFR design incorporates passive cooling capability primarily through its Passive Heat Removal System (PHRS). During accidents, the PHRS allows decay heat to be transferred from the core to a pool of water surrounding the guard vessel, which transitions to long-term air cooling upon water depletion. All of this takes place without operator action or need for moving parts or power supply. Overall, when combined with natural circulation of liquid lead inside of the reactor vessel, this passive system fully relies on natural circulation, thermal radiation and boiling mechanisms to transport decay heat from the core to the atmosphere. In this study, complementary Computational Fluid Dynamics (CFD) and system code analyses were performed to assess the passive cooling ability of the Westinghouse LFR design during station blackout (SBO) conditions. The postulated scenario examined in this study is the longer-term phase of the SBO event, with the RCPs and PHEs assumed to be inactive and the water inventory in the pool exterior to the guard vessel fully depleted, thus relying purely on air cooling as the ultimate heat sink. The CFD analysis was conducted with Siemens STAR-CCM+ code using, as domain, the primary lead pool and with boundary conditions provided by the containment code GOTHIC. The CFD analyses provided high fidelity resolution of the three-dimensional natural circulation flow patterns formed throughout the reactor vessel. The results of the study not only provided confirmation of the passive cooling capability of the Westinghouse LFR design during an SBO event, but also provided granular input for vessel structural analysis activities accounting for thermal gradients developed during an SBO event.
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Verdult, Michiel, Raymond Marchee, and Guus Hommel. "Ductile Failure Limit State Design of High Strength Steel Tension Members With Large Stress Concentrations." In ASME 2011 30th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2011. http://dx.doi.org/10.1115/omae2011-49228.

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The ultimate limit state of structural tension members with stress concentrations due to geometrical (non-welding related) stress raisers is investigated. Examples of such members are pad eyes, brackets etc. The influence of the application of high strength steels (up to S690) is taken into account. The focus lies on members with a predominant static loading regime. Such members frequently occur in the marine environment as parts of lifting appliances and handling systems or as a structural detail of equipment foundations, located outside the fatigue-prone regions of the hull girder. Typically, design stresses at the stress concentration approach the yield limit of the material. Common yield criteria cannot be applied to such peak stresses, due to the small margin between design and yield. Usually, the strength integrity is based on the nominal stresses in the critical cross section. Goal of the study is to determine the ductile failure limit with a method suited for design purposes. This would enable an ultimate limit state design approach and improve the structural safety philosophy. Main question is how the post yield behavior up to failure of a notched section is influenced by the stress gradient and the properties of the high strength materials. For this purpose, the applicability of two damage models based on the work of Rice & Tracey [8] (void growth model) and Bonora [1] (damage mechanics) is studied. In combination with elastoplastic finite element analysis these models enable the prediction of local ductile crack initiation. Calculations are performed on slender tensile members with a geometrical stress raiser, assuming a range of structural steel qualities and using a static loading regime. The results are verified using small scale laboratory tests. It is shown that isolated (non-redundant) tensile members with stress raisers feature a static ductile failure mode similar to that of uniform tensile specimen. Their failure loads can be determined as the product of the material’s tensile strength and the net section area, in the same way as for uniformly stressed members. These findings are valid up to S690 materials and clear the path to a safe and sound application of such materials based on an ultimate limit state approach. It was found that the ultimate limit state is governing design for higher strength steel members with a relatively low stress concentration. A severe stress raiser may be beneficial for efficient design of high strength members, since it allows a design stress in the notch up to yield without compromising the safety up to failure. Damage calculations were found superfluous for isolated member ultimate limit state design. Damage results, however, compare well with the failure mode observed. This is useful for the design of highly stressed notches in details which are surrounded by a large main structure, providing a huge reserve strength capacity. For these so-called embedded stress raisers an ultimate load approach is not possible due to the absence of a critical cross section. Damage mechanics can then be applied to determine a failure point in terms of stress and strain, allowing an ultimate limit state design for these stress peaks as well.
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Reports on the topic "1-safe nets"

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Lamarque, Hugh, and Hannah Brown. Key Considerations: Cross-Border Dynamics Between Uganda and Kenya in the Context of the Outbreak of Ebola, 2022. Institute of Development Studies, December 2022. http://dx.doi.org/10.19088/sshap.2022.043.

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Abstract:
This brief summarises key considerations concerning cross-border dynamics between Uganda and Kenya in the context of the outbreak of Ebola (Sudan Virus Disease, SVD) in Uganda. It is part of a series focusing on at-risk border areas between Uganda and four high priority neighbouring countries: Kenya; Rwanda; Tanzania, and South Sudan. The outbreak began in Mubende District, Uganda on 19 September 2022, approximately 340km from the Kenyan border. At the time of writing (December 2022), the outbreak had spread to eight Ugandan districts, including two in the Kampala metropolitan area. Kampala is a transport hub, with a population over 3.6 million. While the global risk from SVD remains low according to the World Health Organization (WHO), its presence in the Ugandan capital has significantly heightened the risk to regional neighbours. Kenya is categorised as a priority level 1 country, following a case in Jinja on the road between Kampala and the Kenyan border, on 13 November 2022. A total of 23 suspected cases were tested in Kenya up to 1 December 2022, all with negative results. To date, no case of SVD has been imported into the country from Uganda. This brief provides details about cross-border relations between the two states, the political and economic dynamics likely to influence these, and the specific areas and actors most at risk. The brief is based on a rapid review of existing published and grey literature, news reports, previous ethnographic research in Kenya and Uganda, and informal discussions with colleagues from the International Organisation for Migration, UNICEF, UNDP, Save the Children, the Kenyan Red Cross Society, the Kenyan Ministry of Health (MoH) and Ministry of Livestock, Agriculture and Fisheries in Kenya, and the Safe Water and AIDS project in Kisumu. It was requested by the Collective Service, written by Hugh Lamarque (University of Edinburgh) and Hannah Brown (Durham University) and supported by Olivia Tulloch (Anthrologica). It was further reviewed by colleagues from Anthrologica, the Institute of Development Studies, and the Collective Service. This brief is the responsibility of SSHAP.
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