The Nonlinear Roll Damping of a FPSO Hull

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Allan C. de Oliveira ◽  
Antonio Carlos Fernandes
Keyword(s):  
Nonlinear Damping ◽  
Challenging Problem ◽  
Roll Damping ◽  
Ship Hulls ◽  
Damping Behavior ◽  
Industry Standards ◽  
Long Time ◽  
Technological Developments ◽  
Traditional Approaches ◽  
The 19Th Century

The ship-rolling problem is a subject that has been studied for a long time. Since Froude's time (in the 19th century) to nowadays, this subject was revisited several times in order to adjust the theory to changes in ship hulls, dimensions, materials, appendages, etc. On the other hand, ship analysis technological resources, including both experimental techniques and computational capacity (that did not exist in Froude's time), have also amazingly improved. But despite all those technological developments, the assessment of the nonlinear roll damping of some types of hulls still is a challenging problem. The floating production storage and offloading (FPSO) hull fitted with larger bilge keels, for instance, has behaved in such a way that it is impossible to obtain results from nowadays industry standards via decaying tests. This paper discusses an alternative way to assess the nonlinear damping behavior of FPSO hulls with large bilge keels. Since it is fairly easy to perform decaying tests, the paper also proposes an alternative way to analyze the FPSO properties through this kind of testing by grouping multiple results instead of using only a single test. This artifice brought improvements, such as an increased agreement between the alternative model and the experimental data. The paper also compares the more traditional approaches with the alternative method and finally shows the latter's applicability.

An Alternative to Model the Non-Linear Roll Damping of a FPSO Hull

2010 ◽  
Author(s):  
Allan C. de Oliveira ◽  
Antonio Carlos Fernandes
Keyword(s):  
Technological Development ◽  
Standard Theory ◽  
Viscous Effects ◽  
Roll Damping ◽  
Ship Hulls ◽  
Linear Behavior ◽  
Non Linear ◽  
Long Time ◽  
Xix Century ◽  
Ship Rolling

The ship rolling problem is a subject that has been studied from a long time. From Froude (in the XIX century) to nowadays, this problem was revisited several times in order to adjust the theory to the changes in ship hulls, dimensions, materials, appendages and others. On the other hand, the ship analysis resources technologies including both the experimental techniques and the computational capacity (that not exist in Froude’s time) also have amazingly increased. Although all this technological apparatus, that allows testing a model for several conditions a large number of times, the standard way to estimate the non linear roll damping have not been significantly modified (since Froude’s time!). As a result, some ship applications (as a FPSO, for instance) that require more effective roll suppressor appendages have evidenced behaviors that are not in accordance with the ship industry methodology to predict them. The roll standard theory for ship rolling is, however, a well established theory, based on a solid knowledge about viscous effects in fluids. Hence the question is would it be possible to use all the technological development to get a better approach and estimative of roll damping? This paper will discuss how this may be possible, showing an alternative method to estimate the roll damping and testing for a FPSO with strong non-linear behavior observed in model tests suggesting among other thing alternative ways to perform model testing.

Rancang Bangun Sistem Komunikasi Data Antara Mikrokontroller Atmega8 Dengan Arduino Pada Mesin Roaster Coffe Digital

2020 ◽  
Vol 3 (2) ◽  
pp. 103-113
Author(s):  
Rachmad Ikhsan ◽  
Effendi Effendi
Keyword(s):  
Temperature Sensor ◽  
Data Communication ◽  
Test Results ◽  
Industry Standards ◽  
Long Time ◽  
Roasting Time

Roasting coffee manually is widely applied by coffee producers. This process takes a very long time and is less efficient in terms of productivity for industry standards. This machine  is equipped with a thermocouple sensor as a temperature sensor that will measure the temperature in the roasting cylinder, then equipped with a timer as a reminder of roasting time that ranges from 15 minutes at a temperature of 200 degrees Celsius, this machine  is also equipped with android as a timer controller on the coffee roaster machine. This machine is also equipped with a microcontroller and Bluetooth as a media transmitter and data receiver. From the test results obtained data that Bluetooth can be used for data communication between the microcontroller and Android with a distance of 30 meters in the room, and 12 meters outside the room. If it exceeds that distance, then Bluetooth will not respond back

Centroceras gasparrinii subsp. minor subsp. nov. (Ceramiaceae, Rhodophyta) in the North Adriatic Sea (Mediterranean): molecular and morphological characterization

Phytotaxa ◽  
2019 ◽  
Vol 415 (4) ◽  
pp. 233-239
Author(s):  
MARION A. WOLF ◽  
ALESSANDRO BUOSI ◽  
ABDUL-SALAM F. JUHMANI ◽  
ADRIANO SFRISO
Keyword(s):  
Morphological Characterization ◽  
Type Locality ◽  
Correct Identification ◽  
Cortical Cells ◽  
Western Atlantic ◽  
Gland Cells ◽  
The North ◽  
Red Algal ◽  
Long Time ◽  
The 19Th Century

Centroceras Kützing is a small red algal genus with 18 currently accepted species (Guiry & Guiry 2019), characterized by simple filamentous thalli with erect axes arising from a prostrate system and di-trichotomous branching (Hommersand 1963). The characters used to distinguish species are primarily cortical filament morphology: shape and number of the acropetal cortical cells, shape of gland cells, and shape of spines (Won et al. 2009). The generitype C. clavulatum (C. Agardh) Montagne has been viewed for a long time as a highly variable and cosmopolitan species (Hommersand 1963). Molecular and detailed morphological analyses brought Barros-Barreto et al. (2006) to report that C. clavulatum may consist of a species complex and Won et al. (2009) confirmed this hypothesis identifying eight taxonomic entities phylogenetically segregated from genuine C. clavulatum. Seven of these entities were assigned to the following species: C. gasparrinii (Meneghini) Kützing, C. hommersandii Won, T.O. Cho & Fredericq, C. hyalacanthum Kützing, C. micracanthum Kützing, C. natalensis Won, T.O. Cho & Fredericq, C. rodmanii Won, T.O. Cho & Fredericq, and C. tetrachotomum Won, T.O. Cho & Fredericq, (Won et al. 2009). Centroceras gasparrinii, C. hyalacanthum, and C. micracanthum are three western Atlantic species listed as synonyms of C. clavulatum since the middle of the 19th century and resurrected from the ‘C. clavulatum complex’ by Won et al. (2009). In particular, two of these taxa were described from specimens of the Mediterranean Sea: C. gasparrinii (as Ceramium gasparrinii Meneghini, type locality Palermo, Italy) and C. micracanthum (reported with the synonym Centroceras leptacanthum Kützing, type locality Genoa, Italy). Therefore, the numerous Mediterranean records of C. clavulatum (e.g., Gómez Garreta et al. 2001; Verlaque 2001; Sfriso & Curiel 2007; Taşkýn et al. 2013) most probably belong to one of these two species and have to be re-examined for a correct identification and to understand the spatial distribution of the different taxa (Tsiamis et al. 2010). For this reason, in the last years in Greece (Tsiamis et al. 2010), Spain (Gallardo et al. 2016) and Morocco (Hassoun et al. 2018) accurate sampling and morphological analyses of specimens previously identified as C. clavulatum were conducted to determine their correct taxonomic identities. In all cases the recognized species was C. gasparrinii, which can be distinguished morphologically from the other ones previously known as C. clavulatum by the presence of ovoid gland cells and ovoid terminal acropetal cortical cells (Won et al. 2009). As reported by Tsiamis et al. (2010), Greek samples differed from those described by Won et al. (2009), in the smaller number of periaxial cells (10–12 against 13–19).

scholarly journals Stochastic Inverse Identification of Nonlinear Roll Damping Moment of a Ship Moving at Nonzero-Forward Speeds

2012 ◽  
Vol 2012 ◽  
pp. 1-22 ◽  
Author(s):  
S. L. Han ◽  
Takeshi Kinoshita
Keyword(s):  
Nonlinear Damping ◽  
Rolling Motion ◽  
Forward Speed ◽  
Roll Damping ◽  
Nonparametric Approach ◽  
Nonlinear Responses ◽  
Different Types ◽  
Experimental Trials ◽  
And Control ◽  
Ship Rolling

The nonlinear responses of ship rolling motion characterized by a roll damping moment are of great interest to naval architects and ocean engineers. Modeling and identification of the nonlinear damping moment are essential to incorporate the inherent nonlinearity in design, analysis, and control of a ship. A stochastic nonparametric approach for identification of nonlinear damping in the general mechanical system has been presented in the literature (Han and Kinoshits 2012). The method has been also applied to identification of the nonlinear damping moment of a ship at zero-forward speed (Han and Kinoshits 2013). In the presence of forward speed, however, the characteristic of roll damping moment of a ship is significantly changed due to the lift effect. In this paper, the stochastic inverse method is applied to identification of the nonlinear damping moment of a ship moving at nonzero-forward speed. The workability and validity of the method are verified with laboratory tests under controlled conditions. In experimental trials, two different types of ship rolling motion are considered: time-dependent transient motion and frequency-dependent periodic motion. It is shown that this method enables the inherent nonlinearity in damping moment to be estimated, including its reliability analysis.

Wave Pressure Distributions Along the Midship Transverse Section of a VLCC

2008 ◽  
Author(s):  
Zhi Shu ◽  
Torgeir Moan
Keyword(s):  
Transverse Section ◽  
Roll Damping ◽  
Wave Pressure ◽  
Ship Hulls ◽  
Pressure Distributions ◽  
The Difference ◽  
Hydrodynamic Code ◽  
Long Term Prediction ◽  
External Wave

The external wave pressure distributions along the transverse section in the midship region of a VLCC are evaluated in this paper. The commercial hydrodynamic code WASIM issued by DnV has been adopted to perform the hydrodynamic computation. The ship hulls have been discretized with coarser and finer mesh to investigate the effect of panel size on the hydrodynamic pressures. It is found that the difference between these two mesh finenesses is small. It is also found that the roll damping has a significant influence on the wave pressure of vessel especially in beam sea. A sensitivity analysis is carried out in the sense of assessing the influence of the roll damping on the wave pressure. Finally, the long term prediction of the wave pressure has been compared for different roll damping values.

An Efficient Weighted Residual Time Integration Family

2021 ◽  
pp. 2150106
Author(s):  
Mohammad Rezaiee-Pajand ◽  
S. A. H. Esfehani ◽  
H. Ehsanmanesh
Keyword(s):  
Degrees Of Freedom ◽  
Time Integration ◽  
Nonlinear Damping ◽  
Implicit Methods ◽  
New Family ◽  
Error Analyses ◽  
Damping Behavior ◽  
The Family ◽  
New Strategy ◽  
Time Integration Methods

A new family of time integration methods is formulated. The recommended technique is useful and robust for the loads with large variations and the systems with nonlinear damping behavior. It is also applicable for the structures with lots of degrees of freedom, and can handle general nonlinear dynamic systems. By comparing the presented scheme with the fourth-order Runge–Kutta and the Newmark algorithms, it is concluded that the new strategy is more stable. The authors’ formulations have good results on amplitude decay and dispersion error analyses. Moreover, the family orders of accuracy are [Formula: see text] and [Formula: see text] for even and odd values of [Formula: see text], respectively. Findings demonstrate the superiority of the new family compared to explicit and implicit methods and dissipative and non-dissipative algorithms.

scholarly journals Crisis phenomena in Central Asian direction development of Russian foreign trade in the Orenburg direction in the 1st quarter of the 19th century

2017 ◽  
Vol 6 (2) ◽  
pp. 132-135
Author(s):  
Sergey Valentinovich Lyubichankovskiy
Keyword(s):  
Foreign Trade ◽  
Central Asia ◽  
19Th Century ◽  
Orenburg Region ◽  
Central Asian ◽  
Russian State ◽  
Long Time ◽  
Special Rules ◽  
The Russian Empire ◽  
The 19Th Century

The paper contains analysis of development tendencies of the Russian Empire foreign trade with Central Asian khanates in the first quarter of the 19th century. The authors found that the Russian State didnt pay much attention to the Asian customs policy in this direction for a long time. It was due to the fact that the trade with Central Asian khanates was of exchange and caravan character. The author came to the conclusion that the heads of the Orenburg Region - military and civil governors - made great efforts to change that situation and made special rules for the foreign trade development in the Orenburg Region. It promoted commodity turnover increase. The author proved that in the first quarter of the 19th century the most important element of Central Asian trade development crisis in the Orenburg direction was the fact that merchants from Central Asia dominated Russian merchants in the numerical ratio. However, the ministry of finance and E.F. Kankrin refused to forbid Central Asian merchants to trade at internal Russian fairs as it would result in stagnation in trade and would make prices for goods higher. This problem for the first quarter of the 19th century couldnt be solved as it was connected with the geopolitical status quo existing in the region. It only started to get solutions with an active military advance of Russia to Central Asia in the second half of the 19th century.

scholarly journals Recognition of two great contemporaries

Muzikologija ◽  
2015 ◽  
pp. 147-157
Author(s):  
Melita Milin
Keyword(s):  
19Th Century ◽  
Sigmund Freud ◽  
Academic Career ◽  
Common Denominator ◽  
Professional Goals ◽  
Long Time ◽  
The Common ◽  
The 19Th Century

The common denominator in the careers of two contemporaries and great men, citizens of Austria-Hungary - Leos Jan?cek and Sigmund Freud - was that, in spite of their status as outsiders, they managed to achieve well-deserved recognition. Both non-Germans, they had to surmount a number of obstacles in order to attain their professional goals. The Slavophile Jan?cek dreamed for a long time of success in Prague, which came at last in 1916, two years before a triumph in Vienna. Freud had serious difficulties in his academic career because of the strengthening of racial prejudices and national hatred which were especially marked at the end of the 19th century. After the dissolution of the Empire things changed for the better for the composer, whose works got an excellent reception in Austria and Germany, whereas the psychiatrist had to leave Vienna after the Anschluss.

Biobanking and Privacy Law in Brazil

2015 ◽  
Vol 43 (4) ◽  
pp. 714-725
Author(s):  
Sueli Gandolfi Dallari ◽  
Felipe Angel Bocchi Castellaro ◽  
Iara Coelho Zito Guerriero
Keyword(s):  
Ethical Dilemmas ◽  
Genomic Research ◽  
Research Subjects ◽  
The Sustainable Development ◽  
Privacy Law ◽  
Long Time ◽  
Technological Developments ◽  
Scientific Significance ◽  
Population Scale ◽  
Human Biological Material

Recent scientific and technological developments have promoted the emergence of biobanks on a population scale. Although the storage of human biological material has taken place for a long time, it is only recently that biobanks have acquired a broader scientific significance, especially for genomic research. The increase in biobanks creates many ethical dilemmas, such as the protection of privacy, and creates the need for a new regulatory framework, which must enable the sustainable development of biobanks while also protecting the rights of research subjects and biobank participants.

Psychogenic causes of somatic symptoms in gynecology and obstetrics, psychoanalysis and psychotherapy

1926 ◽  
Vol 22 (11) ◽  
pp. 1283-1289
Author(s):  
B. S. Tarlo
Keyword(s):  
19Th Century ◽  
Somatic Symptoms ◽  
Gynecology And Obstetrics ◽  
Long Time ◽  
The Rich ◽  
Cellular Pathology ◽  
The 19Th Century

The localistic view of the origin and treatment of diseases, which for a long time prevailed in medicine, particularly in gynecology, especially became firmly established in the second half of the 19th century, when Virchow's cellular pathology, looking for sedes morborum in organs, took over the general medical thought. The brilliant development of surgery, which coincided with the triumphant march of bacteriology, antiseptics and asepsis, did not prompt a reassessment of this view of the essence of disease. Soon, however, a reaction to Virchow's cellular pathology rose. The rich results of serology and gematology, studies on immunity, etc., were difficult to reconcile with the old basic views of pathology. The doctrine of internal secretion and the doctrine of constitutions (Martius) contributed even more to the turn in the views on the essence of diseases.

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