Recent Advances in the Prediction and Mitigation of Flow Induced Pulsations in Flexible Risers and Flowlines

2019 ◽  
Author(s):  
S. P. C. Belfroid ◽  
N. González Díez ◽  
H. Korst
Keyword(s):  
Flow Velocity ◽  
Large Scale ◽  
Cyclic Stress ◽  
Test Methods ◽  
Ongoing Research ◽  
Recent Advances ◽  
Large Pressure ◽  
Flexible Risers ◽  
Onset Velocity ◽  
Acoustic Standing Waves

Abstract Flow-induced pulsations in flexible risers and flowlines (FLIP) has been the subject of ongoing research roughly over the last two decades. This phenomenon, also called singing, can cause high vibration and cyclic stress levels in the attached up- and downstream pipe systems, thereby imposing serious limitations on the flowrates through the pipes. FLIP occurs when the flow velocity along the flexible is above a certain onset flow velocity. Large pressure pulsations can appear as a result of a feedback loop mechanism established between vortex shedding at the inner cavities and longitudinal acoustic standing waves. Since FLIP is recommended to be avoided in all cases, the main focus of the research has been to understand the phenomenon and build models to predict the onset velocity. An overview of the experiences in the behavior and prediction of onset data on a large number of field cases is given. Recent advances on the theory and prediction of the onset and behavior of flow induced pulsations are discussed. This ranges from new advanced test methods for acoustic source allocation to full large scale experiments. In addition, new and upcoming anti-FLIP technologies as well as possible mitigation actions available to operators are discussed, by introducing recent field experiences as well as large scale tests.

Konkurrenz zwischen Stieleiche und Buche auf Lothar-Sturmflächen | Competition between pedunculate oak and European beech on Lothar windthrow areas

2009 ◽  
Vol 160 (5) ◽  
pp. 114-123 ◽  
Author(s):  
Daniel Otto ◽  
Sven Wagner ◽  
Peter Brang
Keyword(s):  
Large Scale ◽  
Early Stage ◽  
Tree Height ◽  
European Beech ◽  
Threshold Value ◽  
Test Methods ◽  
Permanent Plots ◽  
Pedunculate Oak ◽  
Competitive Pressure ◽  
Competition Index

The competitive pressure of naturally regenerated European beech (Fagus sylvatica) saplings on planted pedunculate oak (Quercus robur) was investigated on two 1.8 ha permanent plots near Habsburg and Murten (Switzerland). The plots were established with the aim to test methods of artificial oak regeneration after large-scale windthrow. On both plots, 80 oaks exposed to varying levels of competitive pressure from at most 10 neighbouring beech trees were selected. The height of each oak as well as stem and branch diameters were measured. The competitive pressure was assessed using Schütz's competition index, which is based on relative tree height, crown overlap and distance from competing neighbours. Oak trees growing without or with only slight competition from beech were equally tall, while oaks exposed to moderate to strong competition were smaller. A threshold value for the competition index was found above which oak height decreased strongly. The stem and branch diameters of the oaks started to decrease even if the competition from beech was slight, and decreased much further with more competition. The oak stems started to become more slender even with only slight competition from beech. On the moderately acid beech sites studied here, beech grow taller faster than oak. Thus where beech is competing with oak and the aim is to maintain the oak, competitive pressure on the oak must be reduced at an early stage. The degree of the intervention should, however, take the individual competitive interaction into account, with more intervention if the competition is strong.

Withdrawn: A New Secret Sharing Scheme of Large-scale Electronic Voting

2019 ◽  
Vol 12 ◽  
Author(s):  
Ting Liu ◽  
Zhe Cui ◽  
Hongquan Pu ◽  
Jintao Rao
Keyword(s):  
Secret Sharing ◽  
Large Scale ◽  
Electronic Voting ◽  
Secret Sharing Scheme ◽  
Technical Errors ◽  
Electronic Engineering ◽  
Sharing Scheme ◽  
Recent Advances ◽  
Copyright Permission ◽  
Legal Right

The article for the journal Recent Advances in Electrical and Electronic Engineering has been withdrawn on the request of the authors due to some technical errors in the article. Bentham Science apologizes to the readers of the journal for any inconvenience this may cause. BENTHAM SCIENCE DISCLAIMER: It is a condition of publication that manuscripts submitted to this journal have not been published and will not be simultaneously submitted or published elsewhere. Furthermore, any data, illustration, structure or table that has been published elsewhere must be reported, and copyright permission for reproduction must be obtained. Plagiarism is strictly forbidden, and by submitting the article for publication the authors agree that the publishers have the legal right to take appropriate action against the authors, if plagiarism or fabricated information is discovered. By submitting a manuscript the authors agree that the copyright of their article is transferred to the publishers if and when the article is accepted for publication.

scholarly journals Diagnosis of tuberculosis in wildlife: a systematic review

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Jobin Thomas ◽  
Ana Balseiro ◽  
Christian Gortázar ◽  
María A. Risalde
Keyword(s):  
Systematic Review ◽  
Test Performance ◽  
Diagnostic Tests ◽  
Large Scale ◽  
Diagnostic Techniques ◽  
Review Literature ◽  
Meat Industry ◽  
Post Mortem ◽  
Serological Tests ◽  
Ongoing Research

AbstractAnimal tuberculosis (TB) is a multi-host disease caused by members of the Mycobacterium tuberculosis complex (MTC). Due to its impact on economy, sanitary standards of milk and meat industry, public health and conservation, TB control is an actively ongoing research subject. Several wildlife species are involved in the maintenance and transmission of TB, so that new approaches to wildlife TB diagnosis have gained relevance in recent years. Diagnosis is a paramount step for screening, epidemiological investigation, as well as for ensuring the success of control strategies such as vaccination trials. This is the first review that systematically addresses data available for the diagnosis of TB in wildlife following the Preferred Reporting Items of Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The article also gives an overview of the factors related to host, environment, sampling, and diagnostic techniques which can affect test performance. After three screenings, 124 articles were considered for systematic review. Literature indicates that post-mortem examination and culture are useful methods for disease surveillance, but immunological diagnostic tests based on cellular and humoral immune response detection are gaining importance in wildlife TB diagnosis. Among them, serological tests are especially useful in wildlife because they are relatively inexpensive and easy to perform, facilitate large-scale surveillance and can be used both ante- and post-mortem. Currently available studies assessed test performance mostly in cervids, European badgers, wild suids and wild bovids. Research to improve diagnostic tests for wildlife TB diagnosis is still needed in order to reach accurate, rapid and cost-effective diagnostic techniques adequate to a broad range of target species and consistent over space and time to allow proper disease monitoring.

scholarly journals Evaluation of recent advances in recommender systems on Arabic content

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Mehdi Srifi ◽  
Ahmed Oussous ◽  
Ayoub Ait Lahcen ◽  
Salma Mouline
Keyword(s):  
Recommender Systems ◽  
High Performance ◽  
Large Scale ◽  
State Of The Art ◽  
Experimental Results ◽  
Recent Advances ◽  
Research Gap ◽  
Text Preprocessing

AbstractVarious recommender systems (RSs) have been developed over recent years, and many of them have concentrated on English content. Thus, the majority of RSs from the literature were compared on English content. However, the research investigations about RSs when using contents in other languages such as Arabic are minimal. The researchers still neglect the field of Arabic RSs. Therefore, we aim through this study to fill this research gap by leveraging the benefit of recent advances in the English RSs field. Our main goal is to investigate recent RSs in an Arabic context. For that, we firstly selected five state-of-the-art RSs devoted originally to English content, and then we empirically evaluated their performance on Arabic content. As a result of this work, we first build four publicly available large-scale Arabic datasets for recommendation purposes. Second, various text preprocessing techniques have been provided for preparing the constructed datasets. Third, our investigation derived well-argued conclusions about the usage of modern RSs in the Arabic context. The experimental results proved that these systems ensure high performance when applied to Arabic content.

scholarly journals Measurement of flow velocity profiles in tank structures using the prototype device OCM Pro LR

2011 ◽  
Vol 64 (1) ◽  
pp. 263-270 ◽  
Author(s):  
K. Klepiszewski ◽  
M. Teufel ◽  
S. Seiffert ◽  
E. Henry
Keyword(s):  
Flow Velocity ◽  
Large Scale ◽  
Fluid Dynamic ◽  
Waste Water Treatment ◽  
Transport Processes ◽  
Treatment Efficiency ◽  
Cleaning Efficiency ◽  
Cfd Modelling ◽  
Ultrasonic Signals ◽  
Cfd Models

Generally, studies investigating the treatment efficiency of tank structures for storm water or waste water treatment observe pollutant flows in connection with conditions of hydraulic loading. Further investigations evaluate internal processes in tank structures using computational fluid dynamic (CFD) modelling or lab scale tests. As flow paths inside of tank structures have a considerable influence on the treatment efficiency, flow velocity profile (FVP) measurements can provide a possibility to calibrate CFD models and contribute to a better understanding of pollutant transport processes in these structures. This study focuses on tests carried out with the prototype FVP measurement device OCM Pro LR by NIVUS in a sedimentation tank with combined sewer overflow (CSO) situated in Petange, Luxembourg. The OCM Pro LR measurement system analyses the echo of ultrasonic signals of different flow depths to get a detailed FVP. A comparison of flow velocity measured by OCM Pro LR with a vane measurement showed good conformity. The FVPs measured by OCM Pro LR point out shortcut flows within the tank structure during CSO events, which could cause a reduction of the cleaning efficiency of the structure. The results prove the applicability of FVP measurements in large-scale structures.

Development of a Reproducible Method of Formulating and Testing Drilling Fluids

1969 ◽  
Vol 9 (04) ◽  
pp. 403-411 ◽  
Author(s):  
B.K. Sinha ◽  
Harvey T. Kennedy
Keyword(s):  
Large Scale ◽  
Drilling Fluid ◽  
Flow Characteristics ◽  
Field Testing ◽  
Test Methods ◽  
Water Evaporation ◽  
Fluid Loss ◽  
Drilling Fluids ◽  
Testing Procedures ◽  
Asymptotic Values

Abstract Recommendations are made for obtaining consistent and reproducible test data on drilling fluids having identical composition. Previously, such a procedure has been difficult to accomplish even when the fluids were mixed in similar equipment. A survey of work in this area indicates that previous methods have been unsatisfactory because previous methods have been unsatisfactory because (1) the muds are extremely sensitive to the duration and violence of agitation during a normal mixing routine, and (2) gelling of the muds occurs before the properties can reach constant values. This gelling is caused by water evaporation resulting from the increase in temperature associated with the agitation. The work shows that these problems largely can be overcome by (1) agitating the constituents of the drilling fluid more vigorously, (2) maintaining a fairly constant temperature, and(3) Protecting the fluid from evaporation. When these steps are followed, the fluid properties approach asymptotic values that do not change by prolonged or accelerated agitation or by aging for a month. The time required to reach asymptotic values or a stabilized state is from 2 to 6 hours and is a function of the mud composition. Introduction Preparation of drilling fluids in the laboratory to determine their suitability to meet specific drilling requirements or to serve as a base fluid to evaluate the effectiveness of thinners, dispersants or other additives normally begins with combining measured quantities of the constituents and stirring them for a short time in a low-speed mixer. This is done to obtain a uniform mixture and to hydrate clays. Then the fluid is further agitated in a higher-speed device (Hamilton Beach mixer or Waring blender) to disperse more thoroughly and clay particles The biggest obstacle in the laboratory investigation of drilling fluids has been the lack of a method of producing a mixture by which reproducible results of the measured properties could be obtained. Numerous investigators have encountered this difficulty. Prior to 1929, density was the only property of mud that customarily was measured. The use of Wyoming bentonite on a large scale after 1929 was mainly responsible for the development of more elaborate testing procedures and for the application of the principles of colloid chemistry to the drilling fluids. Ambrose and Loomis in 1931 were among the first to recognize the plastic flow characteristics of drilling fluids, although Bingham in 1916 had observed The same phenomenon with dilute clay suspensions. Marsh introduced the Marsh funnel for field testing in 1931. By this time, non-Newtonian characteristics of drilling fluids were established. The Stormer and MacMichael viscometers were used to study the rheological properties of the fluids. In the 1930's and early 1940's, the work conducted by several investigators contributed toward a better understanding of drilling fluids. In the mid 1930's, fluid-loss and the associated mud-cake-forming properties of drilling fluids were recognized as important to the behavior of these fluids. The other properties of drilling fluids, including gel strength, pH, and sand content soon were recognized. In 1937, API published its first recommended procedure for test methods. Since that time, these procedures have been revised periodically. The latest edition, RP-13B, was published in 1961 However, in spite of the recognized need for a method of mixing that provides drilling fluids with stabilized properties, no such method previously has been described. SPEJ P. 403

scholarly journals Redefining the political moment

2011 ◽  
Vol 3 (2) ◽  
pp. 72-89 ◽  
Author(s):  
James Arvanitakis
Keyword(s):  
Large Scale ◽  
Political Action ◽  
The Political ◽  
Ongoing Research ◽  
The Public ◽  
Political Processes ◽  
John Howard ◽  
Conservative Media ◽  
Definition Of ◽  
War Protest

On 16 February 2003, more than half a million people gathered in Sydney, Australia, as part of a global anti-war protest aimed at stopping the impending invasion of Iraq by the then US Administration. It is difficult to estimate how many millions marched on the coordinated protest, but it was by far the largest mobilization of a generation. Walking and chanting on the streets of Sydney that day, it seemed that a political moment was upon us. In a culture that rarely embraces large scale activism, millions around Australian demanded to be heard. The message was clear: if you do not hear us, we would be willing to bring down a government. The invasion went ahead, however, with the then Australian government, under the leadership of John Howard, being one of the loudest and staunchest supporters of the Bush Administrations drive to war. Within 18 months, anti-war activists struggled to have a few hundred participants take part in anti-Iraq war rallies, and the Howard Government was comfortably re-elected for another term. The political moment had come and gone, with both social commentators and many members of the public looking for a reason. While the conservative media was often the focus of analysis, this paper argues that in a time of late capitalism, the political moment is hollowed out by ‘Politics’ itself. That is to say, that formal political processes (or ‘Politics’) undermine the political practices that people participate in everyday (or ‘politics’). Drawing on an ongoing research project focusing on democracy and young people, I discuss how the concept of ’politics‘ has been destabilised and subsequently, the political moment has been displaced. This displacement has led to a re-definition of ‘political action’ and, I argue, the emergence of a different type of everyday politics.

scholarly journals Fluids of the Future

2021 ◽  
Vol 7 ◽  
Author(s):  
Thomas H. Edwards ◽  
Guillaume L. Hoareau
Keyword(s):  
Acute Care ◽  
Fluid Resuscitation ◽  
Large Scale ◽  
Large Temperature ◽  
Ongoing Research ◽  
Military Research ◽  
Animal Data ◽  
Life Saving ◽  
The Future ◽  
Significant Burden

Fluids are a vital tool in the armament of acute care clinicians in both civilian and military resuscitation. We now better understand complications from inappropriate resuscitation with currently available fluids; however, fluid resuscitation undeniably remains a life-saving intervention. Military research has driven the most significant advances in the field of fluid resuscitation and is currently leading the search for the fluids of the future. The veterinary community, much like our civilian human counterparts, should expect the fluid of the future to be the fruit of military research. The fluids of the future not only are expected to improve patient outcomes but also be field expedient. Those fluids should be compatible with military environments or natural disaster environments. For decades, military personnel and disaster responders have faced the peculiar demands of austere environments, prolonged field care, and delayed evacuation. Large scale natural disasters present field limitations often similar to those encountered in the battlefield. The fluids of the future should, therefore, have a long shelf-life, a small footprint, and be resistant to large temperature swings, for instance. Traumatic brain injury and hemorrhagic shock are the leading causes of preventable death for military casualties and a significant burden in civilian populations. The military and civilian health systems are focusing efforts on field-expedient fluids that will be specifically relevant for the management of those conditions. Fluids are expected to be compatible with blood products, increase oxygen-carrying capabilities, promote hemostasis, and be easy to administer in the prehospital setting, to match the broad spectrum of current acute care challenges, such as sepsis and severe systemic inflammation. This article will review historical military and civilian contributions to current resuscitation strategies, describe the expectations for the fluids of the future, and describe select ongoing research efforts with a review of current animal data.

scholarly journals Towards empathetic autism research: Developing an autism-specific Research Passport

2020 ◽  
Author(s):  
Maria Ashworth ◽  
Laura Crane ◽  
Robyn Steward ◽  
Melissa Bovis ◽  
Liz Pellicano
Keyword(s):  
Large Scale ◽  
Preliminary Evaluation ◽  
Research Projects ◽  
Community Members ◽  
Ongoing Research ◽  
Negative Experiences ◽  
Autism Research ◽  
Iterative Design ◽  
Large Scale Testing ◽  
Autistic Adults

Despite a dramatic increase in the amount of autism research taking place, autistic adults often report negative experiences of participating in such research. In other areas where community members report dissatisfaction (e.g., healthcare, criminal justice), ‘passports’ or ‘toolkits’ have been developed. In the current project, we created a Research Passport that could be used by autistic adults and autism researchers when engaging in research. Using a participatory framework, we designed and developed a Research Passport via an iterative design process. First, focus groups with autistic adults (n=9) and autism researchers (n=6) were used to elicit initial ideas for a Research Passport. Findings showed that the Research Passport (1) was perceived to be a useful idea, but not a panacea for all issues in autism research, (2) needed to be universal and flexible, and (3) could have a broad remit (e.g., to record scores on commonly-used standardized tasks that could, with permission, be shared with different researchers). Next, a preliminary evaluation of a prototype Research Passport was conducted via usability testing in three ongoing research projects. Nine autistic participants provided feedback (via a survey), as did three researchers (via interviews). We identified three themes from these data, highlighting how the Research Passport: (1) promoted positive participant-researcher relationships, (2) provided a structure and framework to support existing practices, and (3) needed to be adapted slightly to facilitate usability and manage expectations. Overall, the Research Passport was perceived to be useful in promoting empathetic autism research. Further design and large-scale testing are warranted.

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