Damping Characteristics of Heave Plates Attached to Spar Hull

2012 ◽  
Author(s):  
Nimmy Thankom Philip ◽  
S. Nallayarasu ◽  
S. K. Bhattacharyya
Keyword(s):  
Damping Ratio ◽  
Added Mass ◽  
Offshore Structures ◽  
Viscous Damping ◽  
Wave Excitation ◽  
Damping Characteristics ◽  
Hydrodynamic Response ◽  
Key Factor ◽  
The Relationship ◽  
Insight Into

Damping elements are used in ships and offshore structures as response reduction devices for maintaining the hydrodynamic response within acceptable limits. The use of such elements so far has been based on past experience or using empirical based design approach. An investigation of the wave excitation forces acting on these structures with and without damping elements may give an insight into the damping effects of such elements. Also understanding the flow pattern and the magnitude of flow variation around these elements may be useful to improve the design methods. In the present study, measurement of damping forces and response were carried out to establish the relationship between wave frequency amplitude and damping ratio. It was observed that the damping varies with wave period non-linearly and linearly with wave height. Also it was observed that increase in added mass combined with viscous damping is a key factor for the effectiveness of heave plates in reducing motion response of spar platforms. Of the various configurations tested, the spar with double heave plate at the bottom has higher damping compared to other configurations.

TECHNOLOGY AND ECONOMIC DEVELOPMENT: A LITERATURE REVIEW

2012 ◽  
Vol 09 (05) ◽  
pp. 1250033 ◽  
Author(s):  
HARM-JAN STEENHUIS ◽  
ERIK J. DE BRUIJN
Keyword(s):  
Economic Development ◽  
Literature Review ◽  
Technology Management ◽  
Management Of Technology ◽  
Key Factor ◽  
Technology And Economy ◽  
The Relationship ◽  
Insight Into

Technology is considered as a key factor for economic development. Many authors in the field of technology management mention this impact on economic development as a motivator for their technology oriented study. What is this relationship between technology and economic development? In most studies, the relationship between technology and economy remains implicit. The purpose of this paper is to explore the relationship between technology and the economy. Four literature streams are discussed which each provide insight into this relationship. The paper contributes to the management of technology field by summarizing different views that relate to technology and economy.

scholarly journals Displacement Transmissibility Characteristics of Harmonically Base Excited Damper Isolators with Mixed Viscous Damping

2013 ◽  
Vol 20 (5) ◽  
pp. 921-931 ◽  
Author(s):  
Xiaojuan Sun ◽  
Jianrun Zhang
Keyword(s):  
Damping Ratio ◽  
Harmonic Balance Method ◽  
Nonlinear Damping ◽  
Viscous Damping ◽  
Damping Force ◽  
Response Characteristics ◽  
Damping Characteristics ◽  
Linear Damping ◽  
Frequency Ratios ◽  
Good Agreement

The viscous damping force in the mixed form asfd(x˙)=c1x˙+c2|x˙|x˙can well describe damping characteristics of isolators and dampers in many cases. In this paper, performance characteristics of single-degree-of-freedom (SDOF) linear-stiffness isolators with mixed and piecewise mixed viscous damping are analytically examined under harmonic base excitation. Based on the first-order harmonic balance method (HBM), both relative and absolute displacement transmissibility expressions with the equivalent linear damping coefficient (ELDC) are given. And the analytical calculations show good agreement with the numerical results. Also, the influence of nonlinear damping on the response characteristics is investigated by comparing the transmissibility of linear and nonlinear systems. The resonant frequency always shifts to a lower value as the nonlinear damping component of the forcefd(x˙)=c1x˙+c2|x˙|x˙becomes stronger, and when the damping ratio in the corresponding linear model is relatively high, the relative transmissibility decreases at frequencies higher than the resonance frequency of the corresponding linear damping system and the absolute one increases for the frequency ratios above2. Finally, the displacement transmissibility of a nonlinear isolator with piecewise mixed viscous damping is discussed and the process shows research similarity with the non-piecewise case.

Influence of Tip Clearance on the Hydrodynamic Damping Characteristics of a Hydrofoil

2021 ◽  
Vol 143 (6) ◽  
Author(s):  
Yongshun Zeng ◽  
Zhifeng Yao ◽  
Shijie Zhang ◽  
Fujun Wang ◽  
Ruofu Xiao
Keyword(s):  
Damping Ratio ◽  
Added Mass ◽  
Tip Clearance ◽  
Damping Characteristics ◽  
Hydrodynamic Damping ◽  
Hydraulic Machines ◽  
Bending Mode ◽  
Fluid Load ◽  
Vortex Shedding Frequency ◽  
Work Done

Abstract Tip clearance in hydraulic machines may complicate the fluid–structure interaction (FSI) effects. In this investigation, a mode-based approach (modal work) is evaluated and employed to quantitatively predict the added mass, added stiffness, and hydrodynamic damping ratio, in relation to the first-order bending mode of a vibrating hydrofoil. The investigated relative tip clearance ranges from 0.067% to 2% of the span length. The predicted vortex shedding frequency, natural frequency, and hydrodynamic damping ratio of the hydrofoil are in good agreement with the previously published experimental results, with relative deviations within 9.92%, 6.97%, and 11.23%, respectively. Simulation results show that the added mass, added stiffness, and hydrodynamic damping ratio increase inversely as the tip clearance increases. In particular, as the relative tip clearance increases from 0.067% to 2%, the added mass in still water, the added stiffness, and hydrodynamic damping ratio at a velocity of 10 m/s decrease by 18.66%, 9.36%, and 27.99%, respectively. As the tip clearance increases, the inversely increased pressure difference between the upper and lower surfaces of the vibrating hydrofoil is the main reason for the inversely increased hydrodynamic damping ratio. This is due to the energy leakages via the tip clearance region increase as the tip clearance increases, which may cause less fluid force to resist the vibration of the hydrofoil, resulting in less negative modal work done by the fluid load on the hydrofoil.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

On Metaphysics and the Political: A Polemics of Reading Baudelaire in the 1930s

2019 ◽  
Vol 58 (2) ◽  
pp. 249-259
Author(s):  
Joseph Acquisto
Keyword(s):  
Twentieth Century ◽  
Political Crisis ◽  
The Political ◽  
Modern Poetry ◽  
Progressive Politics ◽  
The World ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

This essay examines a polemic between two Baudelaire critics of the 1930s, Jean Cassou and Benjamin Fondane, which centered on the relationship of poetry to progressive politics and metaphysics. I argue that a return to Baudelaire's poetry can yield insight into what seems like an impasse in Cassou and Fondane. Baudelaire provides the possibility of realigning metaphysics and politics so that poetry has the potential to become the space in which we can begin to think the two of them together, as opposed to seeing them in unresolvable tension. Or rather, the tension that Baudelaire animates between the two allows us a new way of thinking about the role of esthetics in moments of political crisis. We can in some ways see Baudelaire as responding, avant la lettre, to two of his early twentieth-century readers who correctly perceived his work as the space that breathes a new urgency into the questions of how modern poetry relates to the world from which it springs and in which it intervenes.

The Annual Reports of the Prison Commissioners for Scotland and Religion, 1903–1931

2019 ◽  
Vol 48 (1) ◽  
pp. 83-101
Author(s):  
Cameron McKay
Keyword(s):  
Annual Report ◽  
Annual Reports ◽  
Individual Choice ◽  
Drinking Habits ◽  
Parental Neglect ◽  
Late Nineteenth ◽  
Causes Of Crime ◽  
Criminological Theories ◽  
The Relationship ◽  
Insight Into

During the late nineteenth and early twentieth century penologists began to explore the possibility that environment and upbringing, as opposed to individual choice, were the causes criminality. The Prison Commissioners for Scotland, the devolved body who administered prisons north of the border, were not immune to this wider trend. Smith has argued that from the 1890s onwards the Commissioners began to accept that criminality was caused by social problems, namely alcoholism, but also parental neglect, poor education and poverty. In their efforts to test these new criminological theories, the Commissioners began to make more careful enquiries into the backgrounds of their charges. From 1896 to 1931 the Commissioners interviewed a sample of prisoners each year and included the findings in their annual report. Although the main focus of these interviews was on the upbringing and drinking habits of prisoners; by the 1900s the Commissioners seem to have added irreligion to the growing list of etiological causes of crime, and from 1903 onwards prisoners were asked to give details on their religious habits. Although it is debateable how much the Prison Commissioners revealed about the relationship between religion and crime, they did however provide a useful insight into the religiosity of the average prisoner.

The Relationship between Seeker and Spiritual Guide as portrayed in contemporary Western Sufi Autobiographies

2011 ◽  
Vol 5 (2) ◽  
pp. 297-332
Author(s):  
Kate Zebiri
Keyword(s):  
Life Writing ◽  
New Age ◽  
The Self ◽  
Individual Autonomy ◽  
Religious Authority ◽  
The Face ◽  
The Relationship ◽  
Insight Into ◽  
Continuity And Discontinuity

This article aims to explore the Shaykh-mur?d (disciple) or teacher-pupil relationship as portrayed in Western Sufi life writing in recent decades, observing elements of continuity and discontinuity with classical Sufism. Additionally, it traces the influence on the texts of certain developments in religiosity in contemporary Western societies, especially New Age understandings of religious authority. Studying these works will provide an insight into the diversity of expressions of contemporary Sufism, while shedding light on a phenomenon which seems to fly in the face of contemporary social and religious trends which deemphasize external authority and promote the authority of the self or individual autonomy.

Empathy as moderator of gender differences in Chinese insurance agents' business ethical sensitivity

2017 ◽  
Vol 45 (6) ◽  
pp. 1029-1042 ◽  
Author(s):  
Na Zhang ◽  
Jian Zhang ◽  
Jing Wang
Keyword(s):  
Gender Differences ◽  
Business Ethics ◽  
Research Field ◽  
Ethical Sensitivity ◽  
Men And Women ◽  
Insurance Agents ◽  
Factors Associated ◽  
Ethics Research ◽  
The Relationship ◽  
Insight Into

To expand the business ethics research field, and to increase society's understanding of Chinese insurance agents' business ethics, we investigated how gender differences are related to agents' business ethical sensitivity and whether or not these relationships are moderated by empathy. Through a regression analysis of the factors associated with the business ethical sensitivity of 417 Chinese insurance agents, we found that gender played an important role in affecting business ethical sensitivity, and empathy significantly affected business ethical sensitivity. Furthermore, empathy had a moderating effect on the relationship between gender and business ethical sensitivity. Both men and women with strong empathy scored high on business ethical sensitivity; however, men with strong empathy had higher levels of business ethical sensitivity than did women with little empathy. The findings add to the literature by providing insight into the mechanisms responsible for the benefits of empathy in increasing business ethical sensitivity.

AI Narratives

2020 ◽  
Keyword(s):  
Artificial Intelligence ◽  
New Technologies ◽  
Ancient Greece ◽  
Historical Overview ◽  
Intelligent Machines ◽  
Narrative History ◽  
History Of ◽  
Imaginative Thinking ◽  
The Relationship ◽  
Insight Into

This book is the first to examine the history of imaginative thinking about intelligent machines. As real artificial intelligence (AI) begins to touch on all aspects of our lives, this long narrative history shapes how the technology is developed, deployed, and regulated. It is therefore a crucial social and ethical issue. Part I of this book provides a historical overview from ancient Greece to the start of modernity. These chapters explore the revealing prehistory of key concerns of contemporary AI discourse, from the nature of mind and creativity to issues of power and rights, from the tension between fascination and ambivalence to investigations into artificial voices and technophobia. Part II focuses on the twentieth and twenty-first centuries in which a greater density of narratives emerged alongside rapid developments in AI technology. These chapters reveal not only how AI narratives have consistently been entangled with the emergence of real robotics and AI, but also how they offer a rich source of insight into how we might live with these revolutionary machines. Through their close textual engagements, these chapters explore the relationship between imaginative narratives and contemporary debates about AI’s social, ethical, and philosophical consequences, including questions of dehumanization, automation, anthropomorphization, cybernetics, cyberpunk, immortality, slavery, and governance. The contributions, from leading humanities and social science scholars, show that narratives about AI offer a crucial epistemic site for exploring contemporary debates about these powerful new technologies.

Die klingende Ferne; Walter Braunfels’ Opera Die Vögel after Aristophanes’ Birds

2019 ◽  
Vol 11 (3) ◽  
pp. 355-371
Author(s):  
Michael Ewans
Keyword(s):  
Central Theme ◽  
Spiritual Values ◽  
Greek Comedy ◽  
Human Understanding ◽  
The Relationship ◽  
Insight Into

Abstract This article explores the opera Die Vögel (1920) by Walter Braunfels (1882–1954), and its reception of Aristophanes' Birds. The Introduction is substantial, as the work is little known. It is followed by an Overview of each of the two Acts, which discusses in Act I the relationship to Aristophanes (Braunfels discarded the second half of the original Greek comedy and struck out on a completely new path). Then the article analyses the development during Act II of insight into die klingende Ferne (‘the music of far away') by Hopeful, who is the principal human character in Braunfels' adaptation. It is shown that Hopeful's quest for spiritual values almost beyond human understanding is the central theme of the opera; the superiority of the life of birds, which Aristophanes treats humorously in the two parabaseis, is taken seriously in Braunfels' mystical second Act.

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