A Case Study - Life Extension of Offshore Bridge Bearings

2021 ◽  
Author(s):  
Ahmed Abdelkhalek ◽  
Govindavilas Sudhesh ◽  
Anjan Sarkar ◽  
Mohammed Eissa
Keyword(s):  
Cost Savings ◽  
Holistic Approach ◽  
Life Extension ◽  
Case Scenario ◽  
Worst Case ◽  
Maintenance And Repair ◽  
Seasonal Monitoring ◽  
The Impact ◽  
Bridge Bearings

Abstract Structural bearings of 47 offshore platform-link bridges with average age of 40 years were inspected and recommended for replacements due to their poor condition. Replacement of bridge bearings involves major risk and production interruptions given the structural modifications, and critical piping and E&I disconnections required for safe jacking-lifting activities required during the process. This paper presents the approach adopted to assure the integrity of the bridges and extend their lives without the need to replace the bearings. The approach employed failure mode and effect analysis to identifying and narrowing down areas that need focused efforts while tackling the problem. Scenario based structural assessments were carried out to examine the impact of the level of movement-allowing bearings functionality on the integrity of the bridge and its supporting structures; identify critical locations to be targeted during focused inspections; and establish envelopes for monitoring thermal expansion and contraction of the bridges. Guidelines were developed and implemented for integrated inspection-maintenance and repair campaign, which aimed to tackle corrosion issues and to install movement-monitoring indicators. Indicator seasonal monitoring is employed to establish the functionality of bearings on the long-term. The what-if structural assessments revealed that even in the worst-case scenario (in which the bearing are completely jammed) the option of local strengthening of the bridge and its supporting elements is more attractive than bearing replacement. The integrated inspection-maintenance and repair campaigns revealed that excessive corrosion levels observed from historic visual inspections on external non-critical bearing components (e.g: guide plates, angles, etc.) is not indicative of the condition of the internal load-bearing components (pedestals) which experienced much lower corrosion levels. The seasonal monitoring of bridge movements revealed that the 40+ years old Teflon pads are still functional and allow the bridges expansion and contraction. The developed holistic approach enabled demonstration of the fitness for service of the bearings, and provided means for assuring their long-term performance through monitoring. The results assured safety, integrity and delivered significant cost savings through aversion brownfield modifications, and production loss associated with bridge jacking and bearing replacement operations.

scholarly journals Modello di stima dei costi sanitari e della capacity delle terapie intensive in Italia nel trattamento di pazienti affetti da COVID-19: valutazione dell’impatto di remdesivir

ABOUTOPEN ◽  
2020 ◽  
Vol 7 (1) ◽  
pp. 95-102
Author(s):  
Matteo Ruggeri ◽  
Alessandro Signorini ◽  
Carlo Drago ◽  
Francesco Rosiello ◽  
Marco Marchetti
Keyword(s):  
Intensive Care ◽  
Cost Savings ◽  
Sensitivity Analyses ◽  
Low Flow ◽  
Base Case ◽  
Negative Effects ◽  
Case Scenario ◽  
Worst Case ◽  
Scarce Resources ◽  
The Impact

Introduction: Coronavirus disease 2019 (COVID-19) is caused by a severe acute respiratory syndrome coronavirus 2, which is a human coronavirus responsible for a pandemic. Direct interventions, i.e. physical distancing and use of protective devices, can prevent or limit contagions, however, it is also required to evaluate the optimization of limited resources, such as the Intensive Care Unit (ICU). For this purpose, it is relevant to estimate the impact of therapeutic solutions that reduce the probability that the patient transits to ICU in symptomatic subjects and in need of hospitalization. The therapeutic solutions allow a more rapid recovery of the patient and save scarce resources that can be used in the treatment of other patients. Methods: A forecasting model is designed to estimate the impact of one therapeutic solution, i.e. the antiretroviral Remdesivir, on both the capacity of intensive care and the healthcare costs for hospitals when managing the current emergency. A base case is presented as well as a best and a worst case scenario deriving from the sensitivity analyses. Results: The introduction of Remdesivir in patients receiving low-flow oxygen therapy with the purpose of reducing ICU accesses and deaths leads to 431 million euros cost savings and avoids 17,150 hospitalizations in intensive care and 6,923 deaths. In the best case, 294 million euros savings are estimated, whilst in the worst case the model estimates a saving of 512 million euros. Conclusions: Remdesivir has the potential to reduce the negative effects of the Coronavirus disease, improving patient conditions and reducing death tolls, and can also save scarce healthcare resources during this pandemic, resulting in a shorter hospital stay and fewer ICU admissions.

scholarly journals SPATIOTEMPORAL VISUALIZATION OF TSUNAMI WAVES USING KML ON GOOGLE EARTH

2017 ◽  
Vol XLII-2/W7 ◽  
pp. 1291-1299 ◽  
Author(s):  
H. Mohammadi ◽  
M. R. Delavar ◽  
M. A. Sharifi ◽  
M. D. Pirooz
Keyword(s):  
Decision Making ◽  
Disaster Management ◽  
Google Earth ◽  
Disaster Mitigation ◽  
Case Scenario ◽  
Worst Case ◽  
Tsunami Waves ◽  
Spatiotemporal Visualization ◽  
Virtual Globes ◽  
The Impact

Disaster risk is a function of hazard and vulnerability. Risk is defined as the expected losses, including lives, personal injuries, property damages, and economic disruptions, due to a particular hazard for a given area and time period. Risk assessment is one of the key elements of a natural disaster management strategy as it allows for better disaster mitigation and preparation. It provides input for informed decision making, and increases risk awareness among decision makers and other stakeholders. Virtual globes such as Google Earth can be used as a visualization tool. Proper spatiotemporal graphical representations of the concerned risk significantly reduces the amount of effort to visualize the impact of the risk and improves the efficiency of the decision-making process to mitigate the impact of the risk. The spatiotemporal visualization of tsunami waves for disaster management process is an attractive topic in geosciences to assist investigation of areas at tsunami risk. In this paper, a method for coupling virtual globes with tsunami wave arrival time models is presented. In this process we have shown 2D+Time of tsunami waves for propagation and inundation of tsunami waves, both coastal line deformation, and the flooded areas. In addition, the worst case scenario of tsunami on Chabahar port derived from tsunami modelling is also presented using KML on google earth.

scholarly journals Imported dengue in Spain: a nationwide analysis with predictive time series analyses

2019 ◽  
Vol 26 (8) ◽  
Author(s):  
Lidia Redondo-Bravo ◽  
Claudia Ruiz-Huerta ◽  
Diana Gomez-Barroso ◽  
María José Sierra-Moros ◽  
Agustín Benito ◽  
...  
Keyword(s):  
Time Series ◽  
Control Measures ◽  
Severe Dengue ◽  
Vector Surveillance ◽  
Case Scenario ◽  
Worst Case ◽  
Temporal Behaviour ◽  
The Impact ◽  
Near Future ◽  
Local Transmission

Abstract Background Of febrile illnesses in Europe, dengue is second only to malaria as a cause of travellers being hospitalized. Local transmission has been reported in several European countries, including Spain. This study assesses the evolution of dengue-related admissions in Spain in terms of time, geographical distribution and individuals’ common characteristics; it also creates a predictive model to evaluate the risk of local transmission. Methods This is a retrospective study using the Hospital Discharge Records Database from 1997 to 2016. We calculated hospitalization rates and described clinical characteristics. Spatial distribution and temporal behaviour were also assessed, and a predictive time series model was created to estimate expected cases in the near future. Figures for resident foreign population, Spanish residents’ trips to endemic regions and the expansion of Aedes albopictus were also evaluated. Results A total of 588 dengue-related admissions were recorded: 49.6% were women, and the mean age was 34.3 years. One person died (0.2%), 82% presented with mild-to-moderate dengue and 7–8% with severe dengue. We observed a trend of steady and consistent increase in incidence (P < 0.05), in parallel with the increase in trips to dengue-endemic regions. Most admissions occurred during the summer, showing significant seasonality with 3-year peaks. We also found important regional differences. According to the predictive time series analysis, a continuing increase in imported dengue incidence can be expected in the near future, which, in the worst case scenario (upper 95% confidence interval), would mean an increase of 65% by 2025. Conclusion We present a nationwide study based on hospital, immigration, travel and entomological data. The constant increase in dengue-related hospitalizations, in combination with wider vector distribution, could imply a higher risk of autochthonous dengue transmission in the years to come. Strengthening the human and vector surveillance systems is a necessity, as are improvements in control measures, in the education of the general public and in fostering their collaboration in order to reduce the impact of imported dengue and to prevent the occurrence of autochthonous cases.

Assembly System Configuration Design for Reconfigurability Under Uncertain Production Evolution

2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Zhengqian Jiang ◽  
Hui Wang ◽  
Maxim A. Dulebenets ◽  
Junayed Pasha
Keyword(s):  
System Throughput ◽  
Assembly System ◽  
Configuration Design ◽  
System Configuration ◽  
Case Scenario ◽  
Worst Case ◽  
Design Evolution ◽  
Product Evolution ◽  
Concurrent Optimization ◽  
The Impact

Assembly system configuration determines the topological arrangement of stations with defined logical material flow among them. The design of assembly system configuration involves (1) subassembly planning that defines subassembly tasks and between-task material flows and (2) workload balancing that determines the task-station assignments. The assembly system configuration should be flexibly changed and updated to cope with product design evolution and updating. However, the uncertainty in future product evolution poses significant challenges to the assembly system configuration design since the higher cost can be incurred if the assembly line suitable for future products is very different from that for the current products. The major challenges include (1) the estimation of reconfiguration cost, (2) unavailability of probability values for possible scenarios of product evolution, and (3) consideration of the impact of the subassembly planning on the task-station assignments. To address these challenges, this paper formulates a concurrent optimization problem to design the assembly system configuration by jointly determining the subassembly planning and task-station assignments considering uncertain product evolution. A new assembly hierarchy similarity model is proposed to estimate the reconfiguration effort by comparing the commonalities among different subassembly plans of current and potential future product designs. The assembly system configuration is chosen by maximizing both assembly hierarchy similarity and assembly system throughput under the worst-case scenario. A case study motivated by real-world scenarios demonstrates the applicability of the proposed method including scenario analysis.

The Impact of Flexbarrier Ingress on Flexlok Stress

2009 ◽  
Author(s):  
Jing Lu ◽  
Frank Ma ◽  
Zhimin Tan ◽  
Terry Sheldrake
Keyword(s):  
Internal Pressure ◽  
Structural Function ◽  
Analysis Model ◽  
Flexible Pipe ◽  
Case Scenario ◽  
Element Analysis ◽  
Worst Case ◽  
Ongoing Research ◽  
Nominal Size ◽  
The Impact

An unbonded flexible pipe typically consists of multiple metallic and thermoplastic layers, where each layer is designed to provide a specific structural function. The burst resistance against the internal pressure in an unbonded flexible pipe is provided mainly by its Flexlok layer. The Flexlok is made by helically-wound steel wires, with neighbouring wires interlocking each other. Beneath the Flexlok is the Flexbarrier, a polymer layer, acting as the boundary for conveyed fluids. The internal pressure is passed onto the Flexlok through the Flexbarrier layer. Under internal pressure, the Flexbarrier can creep into the gaps between Flexlok wires. Theoretically, the polymer material ingress could reduce the flexibility of the Flexlok due to premature lock-up between Flexlok wires and subsequently increase the stress levels. This study presents a 3D finite element analysis model developed to quantify the stress elevation in the Flexlok wire, caused by the Flexbarrier layer ingress. In terms of Flexlok gap size distribution, both nominal and worst case scenarios are studied. In the nominal scenario, the Flexlok gap sizes are evenly distributed. In the worst case scenario, the Flexlok gap is assumed to be completely closed at one position while the gaps at the neighbouring positions are twice the nominal size. Flexbarrier ingress with different temperatures is also studied. Conclusions are obtained by analyzing the simulation results. The work presented is part of an ongoing research and development project.

scholarly journals Impact of Xylella fastidiosa subspecies pauca in European olives

2020 ◽  
Vol 117 (17) ◽  
pp. 9250-9259 ◽  
Author(s):  
Kevin Schneider ◽  
Wopke van der Werf ◽  
Martina Cendoya ◽  
Monique Mourits ◽  
Juan A. Navas-Cortés ◽  
...  
Keyword(s):  
Xylella Fastidiosa ◽  
Plant Diseases ◽  
Disease Spread ◽  
Economic Damage ◽  
Climatic Suitability ◽  
Case Scenario ◽  
Worst Case ◽  
Ongoing Research ◽  
Phytosanitary Measures ◽  
The Impact

Xylella fastidiosa is the causal agent of plant diseases that cause massive economic damage. In 2013, a strain of the bacterium was, for the first time, detected in the European territory (Italy), causing the Olive Quick Decline Syndrome. We simulate future spread of the disease based on climatic-suitability modeling and radial expansion of the invaded territory. An economic model is developed to compute impact based on discounted foregone profits and losses in investment. The model projects impact for Italy, Greece, and Spain, as these countries account for around 95% of the European olive oil production. Climatic suitability modeling indicates that, depending on the suitability threshold, 95.5 to 98.9%, 99.2 to 99.8%, and 84.6 to 99.1% of the national areas of production fall into suitable territory in Italy, Greece, and Spain, respectively. For Italy, across the considered rates of radial range expansion the potential economic impact over 50 y ranges from 1.9 billion to 5.2 billion Euros for the economic worst-case scenario, in which production ceases after orchards die off. If replanting with resistant varieties is feasible, the impact ranges from 0.6 billion to 1.6 billion Euros. Depending on whether replanting is feasible, between 0.5 billion and 1.3 billion Euros can be saved over the course of 50 y if disease spread is reduced from 5.18 to 1.1 km per year. The analysis stresses the necessity to strengthen the ongoing research on cultivar resistance traits and application of phytosanitary measures, including vector control and inoculum suppression, by removing host plants.

scholarly journals Lossless WDM PON Photonic Integrated Receivers Including SOAs

2019 ◽  
Vol 9 (12) ◽  
pp. 2457 ◽  
Author(s):  
Goki ◽  
Imran ◽  
Porzi ◽  
Toccafondo ◽  
Fresi ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Wavelength Division Multiplexing ◽  
Flip Chip ◽  
Optical Network ◽  
Silicon On Insulator ◽  
Passive Optical Network ◽  
Case Scenario ◽  
Worst Case ◽  
The Impact ◽  
Wdm Transmission

The role of a semiconductor optical amplifier (SOA) for amplifying downstream traffic at optical network terminals (ONT) within a silicon-photonics integrated receiver in a high capacity passive optical network (PON) is investigated. The nearly traveling wave SOA effects are evaluated by considering fabrication and link loss constraints through numerical analysis and experimental validation. The impact of hybrid integration of a SOA chip on a silicon on insulator (SOI) photonic chip using the flip chip bonding technique on SOA design is evaluated through numerical analysis of a multi section cavity model. The performance of the proposed ONT receiver design employing twin parallel SOAs is evaluated experimentally on a 32 × 25 Gb/s OOK WDM transmission system considering cross gain modulation (XGM) and amplified spontaneous emission (ASE) constraints. The XGM impact is evaluated through 32 channel wavelength division multiplexing (WDM) transmission and a likely PON worst case scenario of high channel power difference (~10 dB) between adjacent channels. The impact of ASE is evaluated through the worst-case polarization condition, i.e., when all of the signal is coupled to only one. Successful transmission was achieved in both worst-case conditions with limited impact on performance. SOA results indicate that a maximum residual facet reflectivity of 4 × 10−4 for the chip-bonded device can lead to a power penalty below 2 dB in a polarization-diversity twin SOAs receiver.

Development of a Robust Design of a Wet Etched Co-integrated Pressure Sensor

2011 ◽  
Vol 1299 ◽  
Author(s):  
Wolfgang Schreiber-Prillwitz ◽  
Mikko Saukoski ◽  
Gerhard Chmiel ◽  
Reinhart Job
Keyword(s):  
Robust Design ◽  
Pressure Sensor ◽  
Electrical Signal ◽  
Strong Impact ◽  
Front Side ◽  
Case Scenario ◽  
Worst Case ◽  
Scale Range ◽  
Alignment Errors ◽  
The Impact

ABSTRACTThe performance of a co-integrated silicon pressure sensor for the 1-bar full scale range was optimized. A gain in signal of ca. 5% was calculated and verified by optimizing the piezoresis-tors position on the membrane. The influence of alignment errors between the backside cavity mask and the positions of the piezoresistors on the membrane’s front side were calculated. De-pending on the asymmetry, a maximal electrical signal deviation of 1% was found. The impact of underetching effects (KOH) at the backside mask on electrical signals was also analyzed. Un-deretching has a certain range, alters the membrane size, and has a strong impact on sensor per-formances. In a worst case scenario signal variations caused by underetching could be finally reduced from 15% to 4%.

Lithological controls on soil formation rates and the implications for soil sustainability

2020 ◽  
Author(s):  
Daniel Evans ◽  
John Quinton ◽  
Andrew Tye ◽  
Angel Rodes ◽  
Jessica Davies ◽  
...  
Keyword(s):  
Soil Erosion ◽  
Soil Formation ◽  
Case Scenario ◽  
Worst Case ◽  
Radionuclide Analysis ◽  
Rock Types ◽  
Soil Sustainability ◽  
The Uk ◽  
The Impact ◽  
Cosmogenic Radionuclide

<p>Soils deliver multiple ecosystem services and their long-term sustainability is fundamentally determined by the rates at which they form and erode. Our knowledge and understanding of soil formation is not commensurate with that of soil erosion, but developments in cosmogenic radionuclide analysis have enabled soil scientists to more accurately constrain the rates at which soils form from bedrock. To date, all three major rock types – igneous, sedimentary and metamorphic lithologies – have been examined in such work. Soil formation rates have been measured and compared between these rock types but the impact of rock characteristics such as mineralogy or porosity on soil formation rates has seldom been explored. In this UK-based study, we addressed this knowledge gap by using cosmogenic radionuclide analysis to investigate whether the lithological variability of sandstone governs pedogenesis. Soil formation rates from two arable hillslopes underlain by different types of arenite sandstone were calculated. Rates ranged from 0.090 to 0.193 mm yr<sup>-1</sup> and although the sandstones differed in porosity, no significant differences in soil formation rates were found between them. On the contrary, these rates significantly differed from those measured at two other sandstone-based sites in the UK, and with the rates compiled in global inventory of cosmogenic studies on sandstone-based soils. We suggest that this is due to the absence of matrix and the greater porosities exhibited at our UK sites in comparison to the matrix-abundant, less porous wackes that have been studied previously. We then used soil formation rates to calculate first-order soil lifespans for both of our hillslopes. In a worst case scenario, the lifespan of the A horizon at one of our sites could be eroded in less than 40 years, with bedrock exposure occurring in less than 190 years.  This underlines the urgency required in ameliorating rates of soil erosion. However, we also demonstrate the importance of measuring soil erosion and formation in parallel, at the site of interest, rather than calculating a mean rate from the literature, as we demonstrate soil formation rates can vary significantly among variants of the same rock type.</p><p> </p>

scholarly journals Paradoxes of Poweshiek Skipperling (Oarisma poweshiek) (Lepidoptera: Hesperiidae): Abundance Patterns and Management of a Highly Imperiled Prairie Species

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Ann B. Swengel ◽  
Scott R. Swengel
Keyword(s):  
Tallgrass Prairie ◽  
Fire Management ◽  
First Year ◽  
Case Scenario ◽  
Worst Case ◽  
Abundance Patterns ◽  
In Fire ◽  
Percent Unit ◽  
Oarisma Poweshiek

Although Oarisma poweshiek sometimes occurred in localized abundance, its known range is centered on the highly decimated northern tallgrass prairie of North America. To aid its conservation, we analyze surveys from 1988 to 1997 of populations no longer being found. While we recorded 2403 individuals at 20 sites, five sites had 87% of individuals, while 12 sites had only 2% of individuals. Most surveys during O. poweshiek flight had zero individuals recorded. In peak vegetative characteristics for O. poweshiek, fire management had the highest mean abundance but the lowest median abundance and lowest percent occurrence compared to idling and haying. Mean abundance was by far the lowest in the first year postfire compared to longer since fire. Median abundance and percent unit surveys where O. poweshiek was found indicated higher abundances the longer since fire. Although this skipper occasionally exhibited super-recoveries after fire, the median result in fire-managed occupied sites was zero. In a few years, abundance appeared synchronized across many sites, either low (1993, 1997) or high (1994-1995). It is only through a constant focus on avoiding the worst-case scenario that the rare best-case scenario of long-term population persistence appears possible for O. poweshiek.

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