Experimental and Numerical Investigation of Dynamic Positioning in Level Ice

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Ivan Metrikin ◽  
Sofien Kerkeni ◽  
Peter Jochmann ◽  
Sveinung Løset
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Positioning ◽  
Public And Private ◽  
The Public ◽  
Six Degrees Of Freedom ◽  
Deep Waters ◽  
Ice Conditions ◽  
Level Ice ◽  
Ice Floes ◽  
Novel Model

Offshore operations in ice-covered waters are drawing considerable interest from both the public and private sectors. Such operations may require vessels to keep position during various activities, such as lifting, installation, crew change, evacuation, and possibly drilling. In deep waters, mooring solutions become uneconomical and, therefore, dynamic positioning (DP) systems are attractive. However, global loads from drifting sea ice can be challenging for stationkeeping operations of DP vessels. To address this challenge, the current paper investigates DP in level ice conditions using experimental and numerical approaches. The experimental part describes a set of ice model tests which were performed at the large ice tank of the Hamburg Ship Model Basin (HSVA) in the summer and autumn of 2012. Experimental design, instrumentation, methods, and results are presented and discussed. The numerical part presents a novel model for simulating DP operations in level ice, which treats both the vessel and the ice floes as separate independent bodies with six degrees-of-freedom. The fracture of level ice is calculated on-the-fly based on numerical solution of the ice material failure equations, i.e., the breaking patterns of the ice are not precalculated. The numerical model is connected to a DP controller and the two systems interchange data dynamically and work in a closed-loop. The structures of the models, as well as the physical and mathematical assumptions, are discussed in the paper. Finally, several ice basin experiments are reproduced in the numerical simulator, and the results of the physical and numerical tests are compared and discussed.

Experimental and Numerical Investigation of Dynamic Positioning in Level Ice

2013 ◽  
Author(s):  
Ivan Metrikin ◽  
Sofien Kerkeni ◽  
Peter Jochmann ◽  
Sveinung Løset
Keyword(s):  
Dynamic Positioning ◽  
Public And Private ◽  
The Public ◽  
Numerical Tests ◽  
Deep Waters ◽  
Pack Ice ◽  
Level Ice ◽  
Ice Floes ◽  
Novel Model ◽  
Ice Model

Offshore operations in ice-covered waters are drawing considerable interest from both the public and private sectors. Such operations may involve a requirement for vessels to keep position during various activities, e.g. lifting, installation, crew change, evacuation, and possibly drilling. In deep waters, mooring solutions become uneconomical and therefore dynamic positioning (DP) systems are attractive. However, the ice environment is highly variable with ice features ranging from mild pack ice to pressure ridges and icebergs. This paper focuses on level ice as one of the primary ice types for DP operations in cold waters. The paper presents two major contributions: experimental and numerical. The experimental part is devoted to the description of ice model tests performed at the large ice tank of the Hamburg Ship Model Basin (HSVA) in the summer and autumn of 2012. Experimental design, instrumentation, methods and results are presented and discussed. The numerical part presents a novel model for simulating DP operations in level ice. In the modelling, the vessel and the ice floes are treated as separate independent bodies with 6DOF. The fracture of level ice is calculated on-the-fly based on numerical solution of the ice material failure equations, i.e. the breaking pattern is not pre-calculated. The numerical model is connected to the DP controller and the two systems interchange data dynamically and work in a closed loop. The structures of the models as well as the physical and mathematical assumptions are discussed in the paper. Furthermore, several ice basin experiments are reproduced in the numerical simulation and the results of the physical and numerical tests are compared. To the best of the authors’ knowledge, both accurate ice basin tests of DP in level ice and high fidelity simulations of such experiments are novel and have not been published previously.

Ice Tank Testing of a Surface Buoy for Arctic Conditions

2008 ◽  
Author(s):  
Oddgeir Dalane ◽  
Ove Tobias Gudmestad ◽  
Sveinung Lo̸set ◽  
Jo̸rgen Amdahl ◽  
Tor Erik Hilde`n ◽  
...  
Keyword(s):  
Test Results ◽  
Floating Structures ◽  
Deep Waters ◽  
Ice Drift ◽  
Arctic Conditions ◽  
Ice Conditions ◽  
Level Ice ◽  
Ridged Ice ◽  
Ice Forces ◽  
Multiyear Ice

A moored Shallow Draught Buoy (SDB) for potential operations in Arctic waters was tested during the summer of 2006 in the model laboratory basin at the Hamburg Ship Model Basin (HSVA) in Hamburg. The conceptual design of this buoy was based on the design of the Kulluk exploration vessel which operated in the Beaufort Sea in the 1980’s and early 1990’s. The concept was tested in ice conditions representing level ice, multiyear ice and ridged ice, where the ice thickness, ice drift velocity and flexural strength were varied in the different test runs. Moored structures are believed to be favourable in deep waters with ice present, but there exist insufficient information and data about the actions on and behaviour of moored floating structures in ice to support this. The purpose of the present paper is to evaluate the model test results and look at the dynamic ice loading and response of the structure. The ice forces on the structure were calculated from the structure’s response and response power density spectra were used to evaluate the periodic forces and displacements. Based on the analysis of the test data, an increased understanding of the behaviour of the surface buoy is presented.

scholarly journals Numerical Simulation of Ship Oil Spill in Arctic Icy Waters

2020 ◽  
Vol 10 (4) ◽  
pp. 1394
Author(s):  
Wei Li ◽  
Xiao Liang ◽  
Jianguo Lin ◽  
Ping Guo ◽  
Qiang Ma ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Oil Spill ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Oil Film ◽  
Six Degrees Of Freedom ◽  
Oil Dispersant ◽  
Surface Method ◽  
Water Conditions ◽  
Ice Floes

This paper presents a three-dimensional numerical simulation model of an oil spill for application in emergency treatment methods under icy water conditions. The combined effects of wind, wave, current and ice implemented in our model correspond to Arctic Ocean conditions. A discrete element method combined with an overset grid was adopted to track the trajectory movements of oil film with medium-density ice floes and simulate the flow field of moving ice of large displacement in six degrees of freedom (6DOF). The probability of oil spill area extensions were estimated by a response surface method (RSM). Results showed reduced risk of pollution in icy water conditions and greater drift action of oil film. Accordingly, the spraying location and quantity of oil-dispersant could be rapidly specified.

CONSUMO DE ALIMENTOS PROCESSADOS E ULTRAPROCESSADOS POR ESCOLARES DE ARROIO DO TIGRE, RS

2018 ◽  
Vol 7 (1) ◽  
pp. 157-164
Author(s):  
Rubiane Inara Wagner ◽  
Patrícia Molz ◽  
Camila Schreiner Pereira
Keyword(s):  
Public School ◽  
Nutritional Status ◽  
Private School ◽  
Food Habits ◽  
Cross Sectional Study ◽  
School Students ◽  
Cross Sectional ◽  
Public And Private ◽  
The Public ◽  
Cereal Bars

O objetivo deste estudo foi comparar a frequência do consumo de alimentos processados e ultraprocessados e verificar a associação entre estado nutricional por adolescentes do ensino público e privado do município de Arroio do Tigre, RS. Trata-se de um estudo transversal realizado com adolescentes, com idade entre 10 e 15 anos, de uma escola pública e uma privada de Arroio do Tigre, RS. O estado nutricional foi avaliado pelo índice de massa corporal. Aplicou-se um questionário de frequência alimentar contendo alimentos processados e ultraprocessados. A amostra foi composta por 64 adolescentes com idade média de 12,03±1,15 anos, sendo 53,1% da escola pública. A maioria dos adolescentes encontravam-se eutróficos (p=0,343), e quando comparado com o consumo de alimentos processados e ultraprocessados, a maioria dos escolares eutróficos relataram maior frequência no consumo de balas e chicletes (50,0%) e barra de cereais (51,0%), de 1 a 3 vezes por semana (p=0,004; p=0,029, respectivamente). Houve também uma maior frequência de consumo de alimentos processados e ultraprocessados como pizza (73,5%; p0,001), refrigerante (58,8%; p=0,036) e biscoito recheado (58,8%; p=0,008) entre 1 a 3 vezes por semana na escola pública em comparação a escola privada. O consumo de suco de pacote (p=0,013) foi relatado não ser consumido pela maioria dos alunos da escola particular em comparação a escola pública. Os dados encontrados evidenciam um consumo expressivo de alimentos processados e ultraprocessados pelos adolescentes de ambas as escolas, destacando alimentos com alto teor de açúcar e sódio.Palavras-chave: Hábitos alimentares. Adolescentes. Alimentos industrializados. ABSTRACT: The objective of this study was to compare the frequency of consumption of processed and ultraprocessed foods and to verify the association between nutritional status by adolescents from public and private schools in the municipality of Arroio do Tigre, RS. This was a cross-sectional study conducted with adolescents, aged 10 to 15 years, from a public school and a private school in Arroio do Tigre, RS. Nutritional status was assessed by body mass index. A food frequency questionnaire containing processed and ultraprocessed foods was applied. The sample consisted of 64 adolescents with a mean age of 12.03±1.15 years, 53.1% of the public school. Most of the adolescents were eutrophic (p=0.343), and when compared to the consumption of processed and ultraprocessed foods, most eutrophic schoolchildren reported a higher frequency of bullets and chewing gum (50.0%) and cereal bars (51.0%), 1 to 3 times per week (p=0.004, p=0.029, respectively). There was also a higher frequency of consumption of processed and ultraprocessed foods such as pizza (73.5%, p0.001), refrigerant (58.8%, p=0.036) and stuffed biscuit (58.8%, p=0.008) between 1 to 3 times a week in public school compared to private school. Consumption of packet juice (p=0.013) was reported not to be consumed by the majority of private school students compared to public school. Conclusion: The data found evidenced an expressive consumption of processed and ultraprocessed foods by the adolescents of both schools, highlighting foods with high sugar and sodium content.Keywords: Food Habits. Adolescents. Industrialized Foods.

Listening for the “Still Small Voice” of Mendelssohn’s Domestic Elijah

2015 ◽  
Vol 32 (1) ◽  
pp. 40-77
Author(s):  
Peter Mercer-Taylor
Keyword(s):  
Second Phase ◽  
Divine Presence ◽  
Final Phase ◽  
Public And Private ◽  
The Public ◽  
The Third ◽  
Interpretive Approach ◽  
Will To Live ◽  
Three Phases

The notion that there might be autobiographical, or personally confessional, registers at work in Mendelssohn’s 1846 Elijah has long been established, with three interpretive approaches prevailing: the first, famously advanced by Prince Albert, compares Mendelssohn’s own artistic achievements with Elijah’s prophetic ones; the second, in Eric Werner’s dramatic formulation, discerns in the aria “It is enough” a confession of Mendelssohn’s own “weakening will to live”; the third portrays Elijah as a testimonial on Mendelssohn’s relationship to the Judaism of his birth and/or to the Christianity of his youth and adulthood. This article explores a fourth, essentially untested, interpretive approach: the possibility that Mendelssohn crafts from Elijah’s story a heartfelt affirmation of domesticity, an expression of his growing fascination with retiring to a quiet existence in the bosom of his family. The argument unfolds in three phases. In the first, the focus is on that climactic passage in Elijah’s Second Part in which God is revealed to the prophet in the “still small voice.” The turn from divine absence to divine presence is articulated through two clear and powerful recollections of music that Elijah had sung in the oratorio’s First Part, a move that has the potential to reconfigure our evaluation of his role in the public and private spheres in those earlier passages. The second phase turns to Elijah’s own brief sojourn into the domestic realm, the widow’s scene, paying particular attention to the motivations that may have underlain the substantial revisions to the scene that took place between the Birmingham premiere and the London premiere the following year. The final phase explores the possibility that the widow and her son, the “surrogate family” in the oratorio, do not disappear after the widow’s scene, but linger on as “para-characters” with crucial roles in the unfolding drama.

The Noise Abatement Campaign in Industrializing Japan, 1923–37

Resonance ◽  
2020 ◽  
Vol 1 (3) ◽  
pp. 298-327
Author(s):  
Shuhei Hosokawa
Keyword(s):  
Public Opinion ◽  
Legal Regulation ◽  
Public Realm ◽  
Political Responsibility ◽  
Noise Abatement ◽  
Public And Private ◽  
The Public ◽  
Causal Responsibility ◽  
Kanto Earthquake ◽  
Definition Of

Drawing on Karin Bijsterveld’s triple definition of noise as ownership, political responsibility, and causal responsibility, this article traces how modern Japan problematized noise, and how noise represented both the aspirational discourse of Western civilization and the experiential nuisance accompanying rapid changes in living conditions in 1920s Japan. Primarily based on newspaper archives, the analysis will approach the problematic of noise as it was manifested in different ways in the public and private realms. In the public realm, the mid-1920s marked a turning point due to the reconstruction work after the Great Kantô Earthquake (1923) and the spread of the use of radios, phonographs, and loudspeakers. Within a few years, public opinion against noise had been formed by a coalition of journalists, police, the judiciary, engineers, academics, and municipal officials. This section will also address the legal regulation of noise and its failure; because public opinion was “owned” by middle-class (sub)urbanites, factory noises in downtown areas were hardly included in noise abatement discourse. Around 1930, the sounds of radios became a social problem, but the police and the courts hesitated to intervene in a “private” conflict, partly because they valued radio as a tool for encouraging nationalist mobilization and transmitting announcements from above. In sum, this article investigates the diverse contexts in which noise was perceived and interpreted as such, as noise became an integral part of modern life in early 20th-century Japan.

The public and the private: reconfiguring the interrelationship during a civil act

2019 ◽  
pp. 53-69
Author(s):  
Natalia Kostenko
Keyword(s):  
Public Sphere ◽  
Public Space ◽  
Rapid Development ◽  
Online Communication ◽  
Decisive Role ◽  
Physical Interaction ◽  
Bare Life ◽  
Public And Private ◽  
The Public ◽  
The Public Sphere

The subject matter of research interest here is the movement of sociological reflection concerning the interplay of public and private realms in social, political and individual life. The focus is on the boundary constructs embodying publicity, which are, first of all, classical models of the space of appearance for free citizens of the polis (H. Arendt) and the public sphere organised by communicative rationality (Ju. Habermas). Alternative patterns are present in modern ideas pertaining to the significance of biological component in public space in the context of biopolitics (M. Foucault), “inclusive exclusion of bare life” (G. Agamben), as well as performativity of corporeal and linguistic experience related to the right to participate in civil acts such as popular assembly (J. Butler), where the established distinctions between the public and the private are levelled, and the interrelationship of these two realms becomes reconfigured. Once the new media have come into play, both the structure and nature of the public sphere becomes modified. What assumes a decisive role is people’s physical interaction with online communication gadgets, which instantly connect information networks along various trajectories. However, the rapid development of information technology produces particular risks related to the control of communications industry, leaving both public and private realms unprotected and deforming them. This also urges us to rethink the issue of congruence of the two ideas such as transparency of societies and security.

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