Calibration of Design Conditions Based on Long Term Top Tension for Catenary Risers

2012 ◽  
Author(s):  
Fernando Jorge Mendes de Sousa ◽  
Luís Volnei Sudati Sagrilo ◽  
Edison Castro Prates de Lima ◽  
Arnaldo Papaleo
Keyword(s):  
Loading Conditions ◽  
Computational Costs ◽  
Extreme Response ◽  
Vessel Response ◽  
Riser Design ◽  
Extreme Responses ◽  
The Way

Response based approaches are not common in riser design. Due to the high computational costs associated to these methodologies, it is usual to replace the calculation of extreme long term responses by the calculation of responses to a few number of artificial sea states, supposed extreme. However, this hypothesis may not always be applicable. The extreme response of a riser is influenced by several factors. For instance, vessel response motions resonance can occur for waves of periods lower than the ones associated to the desired long term period. In this way, this work has two main objectives. The first is to propose a computationally feasible methodology to calculate long term extreme responses; the second is to calibrate loading conditions, based on the long term responses, to be used when designing catenary risers. The parameter selected to represent the response is the centenary (100y) riser top tension. The utilization of the proposed methodology is illustrated by a case study where three possible positions for a turret in a FPSO hull were compared. The obtained results indicate that this methodology can contribute to substantial changes in the way risers are designed, focusing on the response instead of on the occurrence of extreme sea states.

FROM LONG-TERM PATTERNS OF SEASONAL HUNGER TO CHANGING EXPERIENCES OF EVERYDAY POVERTY: NORTHEASTERN GHANA C. 1930–2000

2006 ◽  
Vol 47 (2) ◽  
pp. 181-205 ◽  
Author(s):  
JÉRÔME DESTOMBES
Keyword(s):  
Statistical Evidence ◽  
West African ◽  
Anthropometric Data ◽  
Poor Diet ◽  
John Hunter ◽  
History Of ◽  
The 1960S ◽  
The Way

This article is a West African case-study of the nutritional history of everyday poverty. It draws on unusually rich statistical evidence collected in northeastern Ghana. In the 1930s, pioneer colonial surveys revealed that seasonal poor diet was pervasive, by contrast with undernourishment. They pave the way for constructing a new set of anthropometric data in Nangodi, a savanna polity where John Hunter completed a classic study of seasonal hunger in the 1960s. A re-survey of the same sections and lineages c. 2000, during a full agricultural cycle, shows a significant improvement in nutritional statuses, notably for women.

Short and Long Term Extreme Reliability Analysis Applied to Floating Wind Turbine Design

2011 ◽  
Author(s):  
Timothe´e Perdrizet ◽  
Daniel Averbuch
Keyword(s):  
Wind Turbine ◽  
International Energy Agency ◽  
Energy Agency ◽  
Floating Wind Turbine ◽  
Extreme Response ◽  
Short And Long Term ◽  
Turbine Design ◽  
Wave Induced

This paper describes and exemplifies an efficient methodology to assess, jointly and in a single calculation, the short and long terms failure probabilities associated to the extreme response of a floating wind turbine, subjected to wind and wave induced loads. This method is applied to the realistic case study OC3-Hywind used in phase IV of the IEA (International Energy Agency) Annex XXIII Offshore Code Comparison Collaboration. The key point of the procedure, derived from the outcrossing approach, consists in computing the mean of the outcrossing rate of the floating wind turbine response in the failure domain over both the short term variables and the ergodic variables defining long term parameters.

scholarly journals Structural Safety Assessment of Marine Operations From a Long-Term Perspective: A Case Study of Offshore Wind Turbine Blade Installation

2019 ◽  
Author(s):  
Amrit Shankar Verma ◽  
Zhen Gao ◽  
Zhiyu Jiang ◽  
Zhengru Ren ◽  
Nils Petter Vedvik
Keyword(s):  
Failure Probability ◽  
Safety Assessment ◽  
Routine Activity ◽  
Structural Safety ◽  
Offshore Wind Turbine ◽  
Structural Failure ◽  
Blade Root ◽  
Extreme Response

Abstract A marine operation is a complex non-routine activity of limited duration carried out in offshore environment. Due to safety reasons, these operations are normally performed within specific sea state limits, which are derived from numerical modelling and analysis of hazardous events. In view of the uncertainties in the assessment of structural responses under stochastic environmental conditions, these limiting curves correspond to a target structural failure probability recommended in offshore standards (for example, 10−4 per operation as specified by DNV-GL). However, one of the main limitations is that these curves do not reflect site-specific safety assessment. The current paper presents a novel methodology for assessing the structural safety level of marine operations from a long-term perspective. The methodology includes estimation of extreme response distribution under all possible operational sea states (i.e. the operational domain under the limiting sea states) for a given offshore site and is compared to the response limit to obtain an average failure probability. A case study is also presented for a blade root mating process onto preassembled hub using a jack-up crane vessel and risk of impact between root and hub is considered critical. Global time-domain simulations are performed using multibody dynamics, and extreme value distributions for impact velocities are derived for different wind-wave conditions. The allowable impact velocity between the blade root and the hub is determined by an explicit finite element analysis of the damage at the blade root. Finally, the average failure probabilities considering the operational domain are obtained for four different European offshore sites and are compared to the target level of structural failure probability considered for the limiting sea states.

scholarly journals How is Supply Chain Visibility Affecting SME's Operating in International Supply Chains?

2021 ◽  
Author(s):  
◽  
Gordon Kenneth Smart
Keyword(s):  
Supply Chain ◽  
Supply Chains ◽  
Risk Sharing ◽  
Negative Consequences ◽  
Positive Attribute ◽  
Shared Goals ◽  
The Way

<p>Supply chain visibility is generally seen as a positive attribute for individual supply chain partners and the supply chain as a whole. There is limited research on how increasing levels of supply chain visibility can impact individual organizations, particularly smaller entities (SME's). This paper uses an Australasian SME (Orion) as a case study to investigate how increasing visibility is affecting them and the way they operate within international supply chains.  The results indicate that increasing visibility can pose significant challenges and potentially negative consequences for smaller organizations. In addition to the extra resources required and complexity for the SME itself, diverging expectations and a lack of trust between supply partners can negatively impact on supply chain relations and long term supply chain innovation.  Within the supply chains Orion operates, increasing visibility does not appear to be leading to improvements in collaboration, risk sharing or shared goals. Viewed through the lens of Michael Porter's five forces model Orion is in a precarious environment, although there remain options for increased visibility to be used to Orion's advantage.</p>

Long Term Failure Probability Calculation Method Applied to Riser Design

2008 ◽  
Author(s):  
Timothe´e Perdrizet ◽  
Daniel Averbuch
Keyword(s):  
Failure Probability ◽  
Sea State ◽  
Reliability Method ◽  
Extreme Response ◽  
Probability Calculation ◽  
Riser Design ◽  
The Mean ◽  
Time Invariant ◽  
Wave Induced

A time efficient methodology is described to evaluate the non linear extreme response of a riser connected to a FPSO subjected to wave induced loads in a stationary sea state. It is extended to cover all sea states and thus to assess the long term failure probability of the riser. The short term procedure is based on a classic time variant reliability method. It uses an approximation of the mean outcrossing rate, which is computed with the time invariant reliability method FORM (First Order Reliability Method).

scholarly journals How is Supply Chain Visibility Affecting SME's Operating in International Supply Chains?

2021 ◽  
Author(s):  
◽  
Gordon Kenneth Smart
Keyword(s):  
Supply Chain ◽  
Supply Chains ◽  
Risk Sharing ◽  
Negative Consequences ◽  
Positive Attribute ◽  
Shared Goals ◽  
The Way

<p>Supply chain visibility is generally seen as a positive attribute for individual supply chain partners and the supply chain as a whole. There is limited research on how increasing levels of supply chain visibility can impact individual organizations, particularly smaller entities (SME's). This paper uses an Australasian SME (Orion) as a case study to investigate how increasing visibility is affecting them and the way they operate within international supply chains.  The results indicate that increasing visibility can pose significant challenges and potentially negative consequences for smaller organizations. In addition to the extra resources required and complexity for the SME itself, diverging expectations and a lack of trust between supply partners can negatively impact on supply chain relations and long term supply chain innovation.  Within the supply chains Orion operates, increasing visibility does not appear to be leading to improvements in collaboration, risk sharing or shared goals. Viewed through the lens of Michael Porter's five forces model Orion is in a precarious environment, although there remain options for increased visibility to be used to Orion's advantage.</p>

scholarly journals ‘We … galloped hard and straight over some big stone gaps’: Freedom of the Hunt for Elite Women in Ireland, 1860-1914

2021 ◽  
Vol 7 (1) ◽  
pp. 18-34
Author(s):  
Maeve ORiordan
Keyword(s):  
Physical Activity ◽  
Social Class ◽  
Contemporary Fiction ◽  
Men And Women ◽  
Cross Country ◽  
Stone Walls ◽  
The Way

Hunting was an elite social pastime accessible to both men and women, of the correct social class, throughout the period 1860-1914. Female involvement in this sport preceded their widespread involvement in other sports and pastimes such as tennis and cycling. This article explores the contradictions inherent in women’s involvement in this masculine sport. The sport demanded that participants display contemporary masculine characteristics of bravery, strength, and independence, and yet it was open to both married and unmarried women of the gentry and ascendancy class in Ireland. The sport was a dangerous one, and considerable skill was demanded of all participants. However, daughters of hunting families were not persuaded against joining the hunt, and were instead encouraged to display the necessary skill and competitiveness to ride a horse side-saddle cross-country at speed; jumping stone walls and banks along the way. It was the norm for women to wear adapted dress modelled on masculine hunting attire, however this dress did not diminish their perceived femininity, and was perceived by some in hunting circles as the most alluring form of female dress. The article explores the numbers of women involved in the sport during the period utilising both contemporary fiction and directories. It also provides a case study of one woman’s experience as she partook of the hunt while also battling long term ill health; challenging the contemporary notion of women as inherently weak and unable for rigorous physical activity.

Long-term extreme buffeting response of long-span bridges considering uncertain turbulence parameters

2021 ◽  
Author(s):  
Tor Martin Lystad ◽  
Aksel Fenerci ◽  
Ole Øiseth
Keyword(s):  
Short Term ◽  
Long Span Bridges ◽  
Buffeting Response ◽  
Long Span ◽  
Long Span Bridge ◽  
Extreme Response ◽  
Current Design ◽  
Extreme Responses ◽  
Turbulence Parameters

<p>Long-term extreme response analyses are recognized as the most accurate way to predict the extreme responses of marine structures excited by stochastic environmental loading. In wind engineering for long-span bridges this approach has not become the standard method to estimate the extreme responses. Instead, the design value is often estimated as the expected extreme response from a short-term storm described by an N-year return period mean wind velocity.</p><p>In this study, the long-term extreme buffeting response of a long-span bridge is investigated, and the uncertainty of the turbulent wind field is described by a probabilistic model. The results indicate that the current design practice may introduce significant uncertainty to the buffeting load effects used in design, when the variability in the turbulence parameters as well as the uncertainty of the short-term extreme response is neglected.</p>

scholarly journals Banco Canaima en la encrucijada. La nueva era Estratégica

1993 ◽  
pp. 98-124
Author(s):  
Elvis Zavatti ◽  
Keyword(s):  
Banking Sector ◽  
Financial System ◽  
Foreign Competition ◽  
New Strategy ◽  
The Face ◽  
The Way

This case study develops the decision that must be made by the directors of a Venezuelan bank, Banco Canaima, in an unsophisticated market with a small number of competitors in the face of a reform of the financial system. It discusses what new strategy will be in the short, medium and long term and what direction the company should take: continue to grow or consolidate, as well as the concrete actions that would be taken in each case to implement the chosen strategy and to face the changes in the financial system and the increase of local and foreign competition. The purpose of this case study is to teach students the different obstacles that stand in the way of planning to change an organization’s strategy. Finally, marketing concepts may also be applicable to the activities of the banking sector.

Caregivers' Perceptions of Speech-Language Pathologist Talk About Child Language and Literacy Disorders

2020 ◽  
Vol 29 (4) ◽  
pp. 2049-2067
Author(s):  
Karmen L. Porter ◽  
Janna B. Oetting ◽  
Loretta Pecchioni
Keyword(s):  
Language And Literacy ◽  
Collective Case Study ◽  
Study Approach ◽  
School Aged Children ◽  
Speech Language Pathologist ◽  
Therapy Goals ◽  
Semistructured Interviews ◽  
Types Of Information

Purpose This study examined caregiver perceptions of their child's language and literacy disorder as influenced by communications with their speech-language pathologist. Method The participants were 12 caregivers of 10 school-aged children with language and literacy disorders. Employing qualitative methods, a collective case study approach was utilized in which the caregiver(s) of each child represented one case. The data came from semistructured interviews, codes emerged directly from the caregivers' responses during the interviews, and multiple coding passes using ATLAS.ti software were made until themes were evident. These themes were then further validated by conducting clinical file reviews and follow-up interviews with the caregivers. Results Caregivers' comments focused on the types of information received or not received, as well as the clarity of the information. This included information regarding their child's diagnosis, the long-term consequences of their child's disorder, and the connection between language and reading. Although caregivers were adept at describing their child's difficulties and therapy goals/objectives, their comments indicated that they struggled to understand their child's disorder in a way that was meaningful to them and their child. Conclusions The findings showed the value caregivers place on receiving clear and timely diagnostic information, as well as the complexity associated with caregivers' understanding of language and literacy disorders. The findings are discussed in terms of changes that could be made in clinical practice to better support children with language and literacy disorders and their families.

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