bluuebunny/crossref_metadata_2025 huggingface dataset:
Antioxidant enzyme activities and DNA damage in children with type 1 diabetes mellitus after 12 weeks of exercise
Authors: Woo J , Yeo NH , Shin KO , Lee H‐J , Yoo J , Kang S
Published: February 2010

Objective:  The objectives of this study are to assess the effects of a low‐intensity exercise training which is not risky for children with type 1 diabetes mellitus (T1DM) on the antioxidant enzyme activities and oxidative stresses compared with healthy controls.

Patients and methods:  We studied 10 boys with T1DM (11.21 ± 0.97 age) and 10 age‐matched healthy controls (11.90 ± 1.85 age) during the 12 weeks of moderate intensity aerobic exercise. Measurements included peak oxygen uptake, body composition, blood lipid profiles, glycated haemoglobin (HbA1c), oxidized low density lipoprotein (ox‐LDL), 8‐hydroxy‐2′‐deoxyguanosine, superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities.

Results:  In T1DM patients, the baseline diastolic blood pressure and HbA1c were higher than that in controls (p < 0.05), while the GPx level was lower. The training‐induced DNA damage peak was higher in T1DM patients than in controls (p < 0.05), and exercise improved both SOD and GPx levels.

Conclusion:  Although our exercise programme increase antioxidant enzyme activities, the results of the study demonstrate that low‐intensity aerobic exercise training programme performed over 12 weeks may accelerate adverse effects of antioxidant defence capacity in children with T1DM. Therefore, the future studies should be performed to clarify much more the relationship to exercise and antioxidant capacity in children with T1DM.
Family stress and BMI in young children
Authors: Stenhammar C , Olsson GM , Bahmanyar S , Hulting A‐L , Wettergren B , Edlund B , Montgomery SM
Published: February 2010

Aim:  The aim of this study was to investigate if family stress and parental attachment style are associated with body mass index (BMI) in young children, and identify possible explanations.

Methods:  A cross‐sectional survey with a two‐stage design was used. Parents of 873 children participated. They completed a demographic questionnaire, the Swedish Parenthood Stress Questionnaire (SPSQ), the Relationship Questionnaire (RQ) and reported their children’s television‐viewing habits (as a marker of physical activity). Children’s height, weight and BMI were obtained from a general population‐based register, BASTA. Associations with over‐ and underweight in children were assessed using multiple logistic regression analysis.

Results:  Family stress indicated by SPSQ‐score was associated with suboptimal BMI. Maternal, but not paternal, SPSQ‐stress score was statistically significantly associated with overweight and underweight, with adjusted odds ratios (and 95% confidence interval) of 4.61 (3.11–6.84; p < 0.001) and 3.08 (1.64–5.81; p < 0.001) respectively. Associations between childhood BMI and parental attachment style were identified, but were not independent of maternal SPSQ‐score.

Conclusion:  Our findings support a role for family stress in development of both overweight and underweight among young children. This is likely to be attributed to behavioural mechanisms but a more direct metabolic influence of stress could also be involved.
Long‐term effects of cutting frequency and liming on soil chemical properties, biomass production and plant species composition of Lolio‐Cynosuretum grassland after the cessation of fertilizer application
Authors: Hejcman Michal , Schellberg Jürgen , Pavlů Vilém
Published: February 2010

Question: Is there any effect of cutting frequency and liming on P and K availability in the soil, biomass production and plant species composition after cessation of fertilizer application?

Location: Eifel Mountains, SW Germany.

Methods: The long‐term Grassland Extensification and Nutrient Depletion Experiment was established on a fertilized and mown pasture (Lolio‐Cynosuretum) in 1993. Treatments were: (1) two cuts per year without liming, (2) two cuts with liming, (3) four cuts without liming, (4) four cuts with liming and (5) continued intensive mowing as the control.

Results: From 1993 to 2006, the plant available P concentration in the soil decreased substantially, whereas K concentration decreased only slightly. Biomass production decreased from 7 to 5 t DM ha−1. These trends were affected by cessation of NPK fertilizer application but not by cutting frequency or liming. In 2007, substantial differences in species composition between the control and the two‐cut and four‐cut treatments were recorded, whereas liming had no effect. Higher species richness was recorded in cut treatments compared to the control, but no effects of cutting frequency or liming were observed. Ellenberg indicator values indicated that soil nutrients influenced changes in species composition only marginally.

Conclusions: The decrease in productivity and available soil P and K in favor of species richness was not achieved to any greater extent by four cuts than by two cuts, or by lime application. Although species richness slightly increased, we conclude that the restoration of low productive grasslands cannot be achieved by cutting management.
Optimization of culture conditions for plant regeneration ofPanicumspp. through somatic embryogenesis
Authors: Seo Mi‐Suk , Takahara Manabu , Takamizo Tadashi
Published: February 2010

We developed a rapid and efficient shoot regeneration system forPanicumspp. by adjusting the regeneration medium and studying the responses of different genotypes and the influence of explant types (mature seed, immature embryo and shoot apex). We usedPanicum meyerianum(Nees) andPanicum longijubatum(Stapf) which were shown to perform well, to select the optimal medium for shoot regeneration. The highest frequency of shoot regeneration was obtained on Murashige and Skoog medium supplemented with 30 g L−1maltose and 1 mg L−1N‐phenyl‐N′‐[(1,2,3‐thidiazol‐5‐yl) urea]. The callus formed green spots after 1 week of culture and showed primary green shoots after 2 weeks. In this system, the calli derived from mature seed of ninePanicumgenotypes showed large variation in shoot regeneration ability: from 0 to 69.9% in the frequency of shoot formation and from 0 to 8.4 in the number of shoots per callus. Guineagrass (Panicum maximumJacq.) showed no ability and switchgrass (Panicum virgatumL.) showed low ability to regenerate from mature seed‐derived calli; however, both were able to be regenerated from immature embryos and calli derived from shoot apices. We developed an efficient protocol for high shoot regeneration of variousPanicumgenotypes which provides a foundation for efficient tissue culture and genetic improvement ofPanicum.
Bushmeat Hunting Alters Recruitment of Large‐seeded Plant Species in Central Africa
Authors: Vanthomme Hadrien , Bellé Boris , Forget Pierre‐Michel
Published: February 2010

We investigated the effect of local hunting on plant recruitment at the community level in the Ngotto Forest, Central African Republic. It is the first study of this kind in the afrotropics. To compare our results with previous studies conducted in the neotropics, we used the protocol proposed byNuñez‐Iturri and Howe. We compared animal relative abundances and seed length, density and diversity of seedlings at two sites with contrasting anthropogenic pressures: one with low hunting pressure (LH) and one with high hunting pressure (HH). Furthermore, we investigated how density and diversity of recruitment vary with seed length in the two sites. Both sites exhibit similar soil, climate and tree species composition, and have never been logged. Large mammals (frugivores and herbivores) were extirpated from HH and relative abundance of medium‐sized frugivores drastically decreased in HH compared with LH. In HH, diversity of seedlings was reduced compared with LH, especially for large‐seeded plant species dispersed by large game mammals. The approach used in this study shows promising perspectives to investigate the effects of human disturbances on the regeneration of tropical forests. Furthermore, in the afrotropical context of a lack of data on plant–animal ecological relationships, seed length appears to be a good predictor of the strength of the deficit of plant recruitment due to large mammal extirpation because of hunting. Thus, more efforts are needed to study the ecological roles of large‐seeded plants in order to better understand the effects of their disappearance on tropical forest resilience.
On Integrating Groundwater Transport Models with Wireless Sensor Networks
Authors: Barnhart Kevin , Urteaga Iñigo , Han Qi , Jayasumana Anura , Illangasekare Tissa
Published: February 2010

The emerging technology of wireless sensor networks (WSNs) is an integrated, distributed, wireless network of sensing devices. It has the potential to monitor dynamic hydrological and environmental processes more effectively than traditional monitoring and data acquisition techniques by providing environmental information at greater spatial and temporal resolutions. Furthermore, due to continuing high‐performance computing development, these data may be introduced into increasingly robust and complex numerical models; for instance, the parameters of subsurface transport simulators may be automatically updated. Early field deployments and laboratory experiments conducted using in situ sensor technology and WSNs indicated significant fundamental issues concerning sensor and network hardware reliability—suggesting that investigations should first be conducted in controlled environments before field deployment. A first step in this validation process involves evaluating the predictive capability of a computational advection‐dispersion transport model when incorporating concentration data from a WSN simulation. Data quality is a major concern, especially when sensor readings are automatically fed into data assimilation procedures. The appropriate employment of an independent WSN fault detection service can ensure that erroneous data (e.g., missing or anomalous values) do not mislead the model. Parameter estimation regularization techniques may then deal with remaining data noise. The primary purpose of this study is to determine the suitability of WSNs (and other in situ data delivery technologies) for use in contaminant transport modeling applications by conducting research in a realistic simulative environment.
High Purge Volume Sampling—A New Paradigm for Subslab Soil Gas Monitoring
Authors: McAlary Todd A. , Nicholson Paul J. , Yik Lee K. , Bertrand David M. , Thrupp Gordon
Published: February 2010

Subslab soil gas sampling and analysis is a common line of evidence for assessing human health risks associated with subsurface vapor intrusion to indoor air for volatile organic compounds; however, conventional subslab sampling methods have generated data that show substantial spatial and temporal variability, which often makes the interpretation difficult. A new method of monitoring has been developed and tested that is based on a concept of integrating samples over a large volume of soil gas extracted from beneath the floor slab of a building to provide a spatially averaged subslab concentration. Regular field screening is also conducted to assess the trend of concentration as a function of the volume removed to provide insight into the spatial distribution of vapors at progressive distances away from the point of extraction. This approach minimizes the risk of failing to identify the areas of elevated soil vapor concentrations that may exist between discrete sample locations, and can provide information covering large buildings with fewer holes drilled through the floor. The new method also involves monitoring the extraction flow rate and transient vacuum response for mathematical analysis to help interpret the vapor concentration data and to support an optimal design for any subslab venting system that may be needed.
The prevalence of oilseed rape hypersensitivity in a mixed cereal farming population
Authors: Trinidade A. , Kumar S. , Haji M. , Shakeel M. , Leong P.
Published: February 2010

Clin. Otolaryngol. 2010, 35, 13–17.

Background:  Oilseed rape production is widespread in cereal growing areas. Many patients attending our clinics for seasonal allergy claim that they are allergic to it.

Aim:  To determine the prevalence of oilseed rape allergy in our population.

Population:  General population within a mixed cereal farming area attending a rhinology and allergy clinic in a district general hospital, UK.

Methods & materials:  Retrospective chart analysis. The results of 1475 consecutive patients who underwent skin prick allergy testing over a 2‐year period (January 2003–December 2005) and of 640 consecutive patients over a 1‐year period (September 2008–September 2009) were analysed and compared.

Results:  Allergy to house dust mite was found to be most common (n = 526, 25%) followed by grass pollen (n = 519, 24%) and cereals (n = 429, 20%). Oilseed rape hypersensitivity was relatively uncommon, comprising only 2% of the population tested (n = 28).

Conclusion:  Oilseed rape does not cause significant allergy, even in areas of high production. It is likely that those patients exhibiting oilseed rape allergy may in fact be symptomatic due to the effect of other allergens, acting either synergistically with the oilseed rape allergen, or more likely, in spite of it.
Psychological aspects of adductor spasmodic dysphonia: a prospective population controlled questionnaire study
Authors: Kaptein A.A. , Hughes B.M. , Scharloo M. , Hondebrink N. , Langeveld T.P.M.
Published: February 2010

Clin. Otolaryngol. 2010, 35, 31–38.

Objective:  To examine psychosocial concomitants, illness perceptions, and treatment perceptions in patients with adductor spasmodic dysphonia.

Design:  Prospective controlled cohort study.

Setting:  A tertiary care facility.

Participants:  Forty‐nine out‐patients (38 women, 11 men; average age of 52 years) with adductor spasmodic dysphonia completed a battery of reliable and validated psychometric assessment instruments. Control patients’ data were derived from scores in questionnaires by samples in the formal Manuals of the questionnaires used.

Main outcome measures:  Psychosocial functioning, illness perceptions, and treatment perceptions.

Results:  Scores on psychosocial measures were elevated in male patients especially, indicating levels of psychological morbidity significantly above those seen in the general population. Assessments of illness perceptions and treatment perceptions indicated that patients perceive that they have a very low degree of control over the disorder, and experience a high emotional impact from it. Voice Handicap Index scores illustrated substantial degrees of perceived handicap.

Conclusions:  Adductor spasmodic dysphonia is associated with significant negative psychosocial concomitants, coupled with low perceived control over the condition. Future research should elucidate the implications of illness perceptions and treatment perceptions for the biopsychosocial care of persons with adductor spasmodic dysphonia in order to improve self‐management and enhance quality of life.
Use of UV‐A Energy for Photosynthesis in the Red Macroalga Gracilaria lemaneiformis
Authors: Xu Juntian , Gao Kunshan
Published: February 2010

UV radiation is known to inhibit photosynthetically active radiation (PAR)‐driven photosynthesis; however, moderate levels of UV‐A have been shown to enhance photosynthesis and growth rates of some algae. Here, we have shown that UV‐A alone could drive photosynthetic utilization of bicarbonate in the red alga Gracilaria lemaneiformis as evidenced in either O2 evolution or carbon fixation as well as pH drift. Addition of UV‐B inhibited the apparent photosynthetic efficiency, raised the photosynthetic compensation point and photosynthesis‐saturating irradiance level, but did not significantly affect the maximal rate of photosynthetic O2 evolution. The electron transport inhibitor, DCMU, inhibited the photosynthesis completely, reflecting that energy of UV‐A was transferred in the same way as that of PAR. Inorganic carbon acquisition for photosynthesis under UV alone was inhibited by the inhibitors of carbonic anhydrase. The results provided the evidence that G. lemaneiformis can use UV‐A efficiently to drive photosynthesis based on the utilization of bicarbonate, which could contribute significantly to the enhanced photosynthesis in the presence of UV‐A observed under reduced levels of solar radiation.
Synergistic Effect of Ultrasound and Thiazone–PEG 400 on Human Skin Optical Clearing In Vivo
Authors: Zhong Huiqing , Guo Zhouyi , Wei Huajiang , Guo Long , Wang Chuanxing , He Yonghong , Xiong Honglian , Liu Songhao
Published: February 2010

In this paper, we propose a new physical method in combination with mixed solution of thiazone and polyethylene glycol 400 (thiazone PEG 400 solution) penetration into tissue to assess the skin optical clearing. Four treatments were performed: (1) control group (C); (2) polyethylene glycol 400 (PEG400); (3) 0.25% thiazone (0.25%T); (4) 0.25% thiazone and 5‐min ultrasound (0.25%T/SP). The diffuse reflectance spectra and imaging depth of human skin in vivo at different times were measured by spectroscopy and optical coherence tomography (OCT). The optical clearing efficacy of skin was qualitatively and quantitatively analyzed. The results showed that the diffuse reflectance at 540 nm of samples at 10 min after being treated by 0.25%T/SP decreased by approximately 15.51%, whereas, 0.46%, 4.73% and 5.75% were received in C, PEG400 and 0.25%T, respectively. And at 60 min, the decrease in diffuse reflectance of samples in 0.25%T/SP is about 2.22‐fold, 1.20‐fold compared with that of the samples in PEG 400 and 0.25%T, at 540 nm, respectively. Simultaneously, 0.25%T/SP results in 41.33% increase in OCT 1/e light penetration depth after 60 min. There was a significant difference in the optical clearing effect on skin between ultrasound‐mixed solution of thiazone in combination with PEG 400 and the mixed solution (P < 0.05).
Risk Indicators for Major Hazards on Offshore Installations
Authors: Vinnem Jan Erik
Published: February 2010

The Petroleum Safety Authority Norway took in 1999 the initiative to develop an approach in order to assess trends and status for the risk levels in the Norwegian offshore petroleum industry, covering major hazards, as well as occupational hazards, health hazards and risk perception, HES culture, motivation and communication. The results are expressed on a national level as well on an installation level, where appropriate. Lagging as well as leading indicators are used. There are individual indicators for a number of barrier elements, including fire and gas detection, a number of safety valves, active fire protection and mustering of personnel. Lessons learned from the project are discussed followed by a discussion of how these lessons may be utilised by individual companies to develop risk indicators for individual installations as well as company wide indicators.
A Generalized Mathematical Procedure for Ship Motion Stability Analysis
Authors: Emmanuel- Douglas Ibiba
Published: February 2010

The challenges of providing safe and high performance marine vehicles present strict and often conflicting constraints that require rational and holistic analysis methodologies to obtain efficient design solutions. This paper presents a mathematical framework for stability analysis, which is one of the key elements in the design and operation of ships and floating bodies that still require considerable improvement. The method is based on the application of the Lyapunov stability analysis concept, which has been highly successful in some other engineering and scientific disciplines. The paper presents the fundamental concepts on the applicability of the Lyapunov method to ship motions stability analysis. Governing mathematical models are derived from first principles and interpreted in the context of geometrical and physical interrelationships. The analytical models are primarily developed for the generalized case of non-linear forced non-conservative systems and simplified by linearization in the case of coupled motion for detailed analysis and characterization of stability conditions and domain. The concept of “motion boundedness” is introduced to satisfy requirements of the Lyapunov method to ship motions subjected to continuous excitations. The analysis leads to some valuable deductions and insight that would be useful in the formulation of stability criteria for ships and marine vehicles in general. The most significant contribution is the possibility of explicit determination of geometric and hydrostatics/hydrodynamics parameters that govern ship stability characteristics.
New Evaluation on Ship Strength From the Viewpoint of Stranded Casualties in Coastal Areas Under Rough Weather
Authors: Sasa Kenji , Incecik Atilla
Published: February 2010

It is important to study the safety of “the refugee of harbour” from the viewpoint of port planning. Recently, accidents of stranded vessels which resulted in breaking of the ship hull become very serious in the port operation and the coastal environment. However, these problems have not even been discussed among the coastal engineering and shipbuilding communities. In this study, we summarize the importance of this point by showing the statistic of casualties. Then, the strength of ship hulls is calculated using the strip theory and the basic dynamics of material, when ships are designed to navigate in the ocean. Since the results of calculations cannot explain the reasons for the incidents which resulted in breaking of the ship hull, the possibility of the high stress levels due to cracks is also considered to explain the reasons for these casulties. The results of the predictions can explain that the breaking of the stranded ship hulls may be caused by the high stresses due to cracks on the ship hull. Therefore, in the future the safety of coastal areas outside harbours should be considered by predicting the motions of anchored ships and the fracture mechanics of the ship hull in detail.
CFD Simulation of Wave Run-Up on a Semi-Submersible and Comparison With Experiment
Authors: Iwanowski Bogdan , Lefranc Marc , Wemmenhove Rik
Published: February 2010

Use of CFD tools for industrial offshore applications is a common practice nowadays. So is the need for validation of such tools against experimental results. This paper presents one of the CFD tools, ComFLOW, which solves Navier-Stokes equations and employs an improved Volume of Fluid (iVOF) method to find temporary location of fluid’s free surface. The code is used to simulate flow around a semi-submersible offshore platform due to an incoming regular wave. In particular, wave run-up on the semi’s columns and under-deck fluid impact phenomena are investigated on high-accuracy computational grids with number of cells being in range of 10 millions. Results of numerical simulations are compared with experimental data and focus is on local fluid flow details in immediate vicinity of the platform. Wave run-up on the platform’s columns and fluid pressures at various locations, including under-deck impact, are reported and verified against the experiment for a range of incoming wave heights.
Standardized Risk Models for Formal Safety Assessment of Maritime Transportation
Authors: Vanem Erik , Puisa Romanas , Skjong Rolf
Published: February 2010

The overall purpose of maritime safety regulations is to establish minimum requirements in order to ensure that at least a prescribed level of safety can be maintained. The purpose of Formal Safety Assessment is to evaluate current safety regulations by estimating the average risk levels that may be associated with these minimum requirements, averaged over i.a. time, space and a population of ships, and possibly to recommend improved regulations. In this paper, a standardized structure for conceptual risk models of the most critical accident scenarios pertaining to shipping is proposed. Based on these risk models, detailed event tree models may be developed for particular shiptypes and applications in a straightforward and consistent manner. Such standardized risk models will also facilitate development and integration of software tools and other partial risk models as parts of the overall risk model. The standardized risk models developed in this paper include the risk to life (crew and passengers where applicable), as well as the risk of accidental pollution and financial accident cost related to loss of ship and cargo. There are several benefits from having standardized risk models for use in Formal Safety Assessments. Obviously, standardized risk models, if commonly accepted, will ease the workload of future Formal Safety Assessment applications in that new risk models will not need to be developed on a case by case basis. Improved consistency, comparability and transparency may be achieved which will also ease the evaluation and validation of risk analyses and recommendations from future Formal Safety Assessments.
Identification of Spudcan Fixity for a Jack-Up Rig
Authors: Thanh T. N. , Koh C. G. , Choo Y. S.
Published: February 2010

To estimate soil stiffness parameters under spudcan foundations and assess the performance of a jack-up rig, a strategy for identifying spudcan fixity of a jack-up rig based on the measured acceleration responses is developed. The finite element model of a jack-up rig is set up, in which the interaction of soil and a spudcan foundation is modeled as a system of horizontal, vertical, and rotational elastic springs. The ‘measured’ acceleration responses along each leg is archived by simulating the jack-up under a selected storm loading in the North sea, including random wave, current and wind loadings. The random wave loading is calculated using JONSWAP water surface elevation spectrum in conjunction with Morison’s equation. The spudcan fixity of a jack-up rig is effectively identified using an improved genetic algorithm (GA) method. The identification strategy proposed works by matching the time histories of the measured accelerations up with those of the numerical simulated accelerations through an objective function in GA. The results indicate that the soil stiffness parameters under spudcan foundations are exactly identified in noise free case. Error less than 1.2% in identified rotational and vertical spring stiffnesses of interest is archived with the worst case of 10% noise and only two acceleration measurements at hull. In addition, it is observed that the vertical and rotational stiffness parameters are more accurately identified than the horizontal one. The identified stiffness values of spudcan fixity help to enhance the understanding of jack-up foundation behavior and improve the operational envelop for a specific jack-up design. With full-scale measurements of environmental conditions and dynamic responses of a jack-up rig, this strategy can be employed to verify recent findings on the conservatism of predicting soil stiffness parameters.
Nonlinear Coupling of Unstable Ship Motions in Head Seas: Bifurcation Analysis and Erosion of Safe Basin
Authors: Neves Marcelo A. S. , Vivanco Jerver E. M. , Rodri´guez Claudio A.
Published: February 2010

Parametric rolling in head seas may lead to large roll angles in few cycles with substantial coupling of this mode with heave and pitch. The present paper investigates in depth the essential dynamical characteristics governing the complex coupling of the three modes at the first region of instability of the limits of stability. Bifurcation diagrams and Poincare´ mappings are employed to investigate the appearance of intermittence, multistability and chaos associated with increased values of wave amplitude. Erosion of the safe basin of the coupled system for some sea conditions is also addressed.
Wave-Induced Motions of Gas Cat: A Novel Catamaran for Gas Processing and Offloading
Authors: Thomas Giles , Ford Alexandra , Kibby Landon , Binns Jonathan , Finnie Ian , Kavanagh Neil
Published: February 2010

The preliminary development of the novel concept of using a large catamaran, known as Gas Cat, as a floating natural gas processing and offloading facility is outlined. The proposed system is based on two ship-shaped hulls joined by a spanning superstructure. For off-loading purposes a carrier may dock with or be tethered to the catamaran. A concept design has been developed based on two retrofitted VLCCs allowing for the processing and storage of 1 million bbls of condensate and approximately 240,000 m3 of LNG. A key aspect of the development of this concept is the accurate estimation of the motions of the catamaran in a variety of operational scenarios. Model experiments were conducted in the Model Test Basin of the Australian Maritime College using a 1:78 scale model of two full-form hulls converted into a catamaran configuration. Tests were conducted in head, beam and oblique seas for two hull spacings and a range of wave heights. The experimental results show that, for the range of wave conditions tested, good linearity of the motions can be expected with respect to wave height. An increase in demihull separation was found to significantly reduce the sway, heave and roll motions in beam seas. However a change in demihull separation had little influence on the motions in oblique seas. A change in heading angle from head seas to beam seas significantly increased the sway, heave and roll motions whilst reducing pitch motions. Bow quartering seas was seen to be the worst heading angle for yaw. The results from the experiments allowed the expected motions of the Gas Cat to be determined in extreme weather conditions.
Framework of Ubiquitous Sensor Network for the Crack Monitoring of Offshore Structures
Authors: Lee Kyung-ho , Kim Kyung-su , Han Young-soo , Lee Jung-min , Choi Si-young , Kim Chung-hyun
Published: February 2010

According to climate change, design paradigm for Marine structure is being changed too. Many researches and practices are carried out countermeasures for climate change after extensive damage from TSUNAMI and Hurricane Katrina. And some of these activities are interest on fatigue crack problem. There are only few ways to prevent Marine structure’s fatigue failure as yet. Most one is applying safety factor to structural strength, another one is carry out fatigue status observation by naked eyes. But those ways have some problems about measuring accuracy and observing continuability. Also Carrying out Marine structure design depend on experiences about structural strength has possibility of in-efficiency. And it might not deal with structural safety ensuring by climate changing immediately. According to weather condition and observing location, it even should be impossible to continue monitoring. As previously stated, to improve problems of structural fatigue life monitoring system, this paper introduce convergence technology based on Ubiquitous network system through analyzing system requirements and developing system framework. Also we make a prototype and carry out test to confirm possibility of fatigue strength prediction system based on Ubiquitous sensor network applying to Marine structure.
Computational Method to Assess the Residual Stresses of Thick Plate Joined by Two-Pole Tandem EGW in Marine Vessels
Authors: Lee Jang Hyun , Hwang Se Yun , Yang Yong Sik
Published: February 2010

Shear strakes or deck plates of large container carrier and FPSO vessels are joined by ultra-thick plates whose thickness is more than 60mm. Traditionally FCAW (Flux-Core Arc Welding) has been used to join the ultra-thick plates. However, FCAW has been replaced with EGW (Electro-Gas Welding) since the welding efficiency of EGW is higher than that of FCAW. Two-pole EGW has been applied to vertical position welding by several shipyards. EGW requires one or two layers of bead whereas FCAW requires more than 20 layers of weld bead in thick welding. However it uses higher heat input than FCAW. Therefore high welding residual stresses are generated by EGW. It is known that the high residual stress may shorten the fatigue strength of the joined structure. The residual stress should be investigated when EGW is applied to the thick plate joining. Present study explains a computational method to analyze the residual stress of EGW in the thick plates. Based upon the FEA (finite element analysis), both profile and level of the residual stresses are studied for EH40 TMCP (Thermo-Mechanical Control Process) steel plates with thickness of 80mm. Also, peculiar stresses of butt joint specimens are measured by X-ray diffraction method to assure the results of the FEA model.
Simulation of Behavior of Fatigue Cracks: A Complete Industrial Process on a Typical Connection in a FPSO
Authors: Serror Michelle , Marchal Nicolas
Published: February 2010

To assess FPSO condition, it is necessary to adjust the inspection process and the inspection planning in accordance with the safety target. Crack propagation may be a leading criterion for designing inspection planning and repair planning. In order to realistically anticipate the possible propagation of either cracks not detected during inspection or cracks initiated after this inspection, a joint research project between three French companies (Nexter Systems, CETIM, and Bureau Veritas) has been carried out to obtain improved approach. This approach involves various steps of fatigue crack behavior leading to failure. This paper presents a part of this research dedicated to the development of tools applicable to FPSO structural assessment. This method takes into account the analysis of simultaneous crack propagation. It involves interaction between these cracks. This technique avoids successive re-meshing all along the crack path. Multi-crack initiations are calculated using a multi-axial fatigue damage criterion based on a local approach. A Line Spring Method coupled with a fitted structural stiffness condensation method is used to calculate the stress intensity factors, with a view to determine the crack propagation rate. This method allows monitoring the redistribution of the stresses generated by crack opening. This approach has been then validated on a welded mock-up, which was designed to provide several crack locations in different zones of the structure. An extended instrumentation of this welded structure has allowed tests to check accurately crack initiations and to follow crack propagation. The results are in good agreement with calculation predictions. This approach is now used to assess fatigue crack propagation in a FPSO. An example is provided on a welded connection between bracket and longitudinal stiffener, on the transverse bulkhead where a propagation of four cracks has been followed. This analysis shows an important gain in the fatigue life span prediction versus current fracture mechanics analysis. This gain is mainly due to a better interaction analysis between local cracked area and global structural behavior.
Safety Assessment of Ship Launching Based on Airbags With the Nonlinear Rigidity of Airbags Being Considered
Authors: Ren Huilong , Li Chenfeng , Feng Guoqing , Liu Xiaobo , Zhang Jian
Published: February 2010

Launching based on airbags is an important method of ship launching. However, there has not a scientific method for quantitative assessment on the strength of hull structure and safety of airbags at present. With the increases of tonnage of ships launching on airbags, this problem becomes increasingly apparent and important. With the nonlinear rigidity of air-bags and force equilibrium conditions of ship-hull beam being considered during launching, a method based on full ship FEA was put forward to assess the strength of ship structure and the safety of airbags in this paper. The main contents are as follows: Considering nonlinear rigidity of airbags, a calculation method of rigidity of airbags was studied; Based on the elastic launching calculation, a method of calculating ship motion and force on ship hull was studied with the nonlinear rigidity of elastic foundation being considered; Based on the above condition of ship motions and forces, the stress of hull structure and the force on airbags are calculated by full ship FEA; The safety of a real ship launching based on airbags was assessed, based on the comparison of the results with references, the safety of ship launching by airbags and the reliability of the calculation method in this paper are verified.
Development of a Inclining Test Procedure Applicable to Semi Floating Production Units Moored on Location
Authors: Nogueira Se´rgio
Published: February 2010

The constant modifications that are done aboard floating units have direct impact on the safety requirements regarding stability. With few exceptions these modifications imply on onboard construction (e. g. process plant upgrade), and the correspondent rise of light ship weight. The consequence will be a negative effect on stability, and because the semi submersible has a very low stability margin, a reduction of the capacity for future modifications that will probably be necessary as well as the ability to deballast to lower drafts. According the Rules applicable the modification of the light ship weight that surpasses a defined limit must be checked through an Inclining Test that can only be executed with the unit in sheltered waters. For a Floating Production Unit (FPU) this test is unfeasible because of the operational procedure (the need to disconnect anchor lines and risers, tow and reconnect) and the production downtime. The alternative is to negotiate with the regulatory bodies a penalty for the light ship modifications that imply in a further reduction on the range of stability and the correspondent capacity of the unit the undergo further and necessary modifications. The motivation of this work is to develop an Inclining Test procedure that can be applied to semi submersible floating production units moored on location, without the need to tow to sheltered waters, which will yield results as accurate as the ones obtained through the conventional Inclining Test, and also accepted by the main Classification Societies. To achieve this it is necessary to first determine the accuracy of the conventional Inclining Test accepted by the Classifications Societies by means of a detailed statistical analysis. Then innovations are proposed in the instruments used to measure de physical parameters, the hydrostatic relation between moment and angle, and the test procedure itself with much better accuracy compared to the conventional procedure. Reliable and tested computational tools are developed to model risers and mooring line forces to determine their effect, and statistical tools are proposed to filter wind and wave influence. The result is an acceptable alternative to the conventional Inclining Test that is consistent with the stability rules that apply, permits a reliable determination of the main stability parameters, reduction on the penalties and consequently further and most necessary modifications aboard. This work is based on the author’s thesis for a Masters Degree at COPPE/UFRJ, currently underway at the Graduate Engineering Project Coordination at Rio de Janeiro Federal University.
Risk Based Multi-Objective Simulation of Ship Main Engine Systems
Authors: Baliwangi Lahar , Artana Ketut Buda , Ishida Kenji
Published: February 2010

The research is to understand the behavior of components and systems under various operational conditions, and with various maintenance policies. Therefore, this research is expected to give policy options to management. And further, inform the likely impacts of those options. This research presents a flexible system to simulate the effect of these factors to a system its reliability, operation and the maintenance costs. The model studied consists of failure rate, time to maintain, decision to maintain (or not), degree of how good the maintenance is done, the effect on component after maintenance, the maintenance cost, and the operation cost. A case study of main engine system with its support systems is presented using previous works data. Dynamic risk is presented in this work. It makes it possible to figure more frequently updated risk; therefore, it is easier for the management to modify or to mitigate the possible risk. The simulation shows predictive results for a given scenario of system configuration, operation and maintenance decision in simulating dynamic risk. In addition, this paper is addressed to provide a user friendly tool to simulate the system risk under some designed decisions both operation condition and maintenance policy. The result of a better understanding of system behavior and the risk depend on operation and maintenance policy is expected.
Hydroelastic Response of a Circular Plate in Waves Using Scaled Boundary FEM
Authors: Song Hao , Tao Longbin
Published: February 2010

In this paper, the hydroelastic response of a circular plate excited by plane incident waves is studied using the scaled boundary finite-element method (SBFEM), a novel semi-analytical approach with the combined advantages of both finite-element and boundary-element methods. The governing sixth-order partial differential equation is decomposed into three Helmholtz-type equations and solved semi-analytically by matching the boundary conditions at the edge of the plate. Discretising only the circumference of the plate, the current SBFEM model exhibits excellent computational accuracy and efficiency. The technique can be extended to solve more complex wave-structure interaction problems resulting in direct engineering applications.
Long-Term Statistical Analysis of Typhoon Wave Heights With Poisson-Maximum Entropy Distribution
Authors: Dong Sheng , Liu Wei , Zhang Lizhen , Guedes Soares C.
Published: February 2010

Using the maximum typhoon wave height series observed at Nakagusukuwan Observation Station in Japan, a novel compound distribution, Poisson-maximum entropy distribution, is proposed to calculate typhoon wave height return values. In this paper, both the Annual Maximum method and Peak Over Threshold method are adopted for long-term wave height analysis. Calculation results by Peak Over Threshold method show that the choice of threshold slightly affects the return values of wave height under the same long statistical series. For a relatively short sample by the Peak Over Threshold method, the estimation accuracy is still higher under the condition that the maximum typhoon wave height is included in the statistical sample.
Typhoon Storm Surge Intensity Grade Classification in Qingdao Area
Authors: Dong Sheng , Fan Dunqiu , Shi Xiang , Guedes Soares C.
Published: February 2010

Serious storm surge disasters are frequently caused by the higher tidal level and concomitant huge wave heights toward shoreline. In order to make up the defects of the warning level, which cannot thoroughly describes the magnitude of storm surge, a Poisson Bi-variate Lognormal Distribution (PBLD) is presented to predict typhoon surge intensity. The PBLD model can take account of the joint distribution of bi-variate extreme environmental conditions as well as the typhoon frequency. On the basis of observed tidal level and simultaneously occurred wave height series that are sampled from typhoon processes in Qingdao coastal area of China since 1949, the return periods of typhoon surge are estimated. A new criterion is put forward to classify intensity grade of disaster-induced typhoon surges. Practical cases indicate that the new criterion is clear in probability concept, easy to operate, and fits to the calculation of typhoon surge intensity. The procedure with the proposed statistical model will be a reference for the disaster mitigation in the other coastal area influenced by typhoons.
Structural Response of a Multi-Hinged Articulated Offshore Tower Under Seismic Excitation
Authors: Hasan Syed Danish , Islam Nazrul , Moin Khalid
Published: February 2010

Articulated towers are the compliant offshore structures that are designed with high degree of compliancy in horizontal direction and to remain relatively stiff in vertical direction. The nonlinear effects due to large displacements, large rotations and high environmental forces are of prime importance in the analysis. This paper investigates the structural response of a 580 m high multi-hinged articulated tower under different seismic sea environment in a water depth of 545 m. The articulated tower is represented as an upright flexible pendulum supported on the sea-bed by a mass-less rotational spring of zero stiffness while the top of it rigidly supports a deck in the air; a concentrated mass above still water level (SWL). For computation of seismic loads, the tower is idealized as a “stick” model of finite elements with masses lumped at the nodes. The earthquake response is carried out by time history analysis using real sets of Californian earthquakes. Disturbed water particle kinematics due to seismic shaking of sea bed is taken into consideration. Nonlinear dynamic equation of motion is formulated using Lagrangian approach. The approach is based on energy principle that relates the kinetic energy, potential energy and work of the system in terms of rotational degree-of-freedom. The solution to the equation of motion is obtained by Newmark-β scheme in the time domain that counters the nonlinearities associated with the system in an iterative fashion. It is observed that with the increase in water depth, additional hinges are required to compensate the increased bending moment due to additional earthquake loads. Analysis results are compared and presented in the form of time-histories and PSDFs of various responses along with combined responses due to horizontal and vertical component of ground motion using direct sum and SRSS method.
Analysis of Barriers in Marine Operations on Offshore Oil Installations
Authors: Skogdalen Jon Espen , Haugen Stein , Heldal Frode , Holo Birger , Okstad Eivind , Steen Sunniva A. , Vinnem Jan Erik
Published: February 2010

The project Risk Modeling – Integration of Organizational, Human and Technical factors is developing a model for quantifying barrier performance related to major risk hazards (OMT-model). The model combines knowledge relating to organizational, human and technical aspects, and is developed in close relationship between research centers, universities and offshore operators. The OMT-model has been tested for process leakages on onshore plants with good results. The same methodology has been used to identify the risk influence factors (RIF) — or Performance Shaping Factors — related to marine operations. One of the main risk contributors in a quantified risk analysis (QRA) is collision between FPSO and shuttle tanker and the method is used on this case. QRAs together with data from the yearly project “Trends in Risk Level” performed by the Petroleum Safety Authority in Norway, incident and accident investigations, operating procedures and expert judgment form the basis for identifying the RIFs and the results are summarized in this paper. By controlling the RIFs and accompanying identified root causes the probability and consequences of a hazard or accident will be largely reduced compared with the present situation.
Cryogenic Fluid Flow in the Insulation Wall of the Cargo Containment System
Authors: Park Bum Jin , Lee Hee Bum , Rhee Shin Hyung , Bae Jun Hong , Lee Kyung Won , Jeong Wang Jo , An Sang Jun
Published: February 2010

The cargo containment system (CCS) for ships carrying cryogenic fluid consists of at least two levels of barriers and insulation layers. It is because, even though there is a small amount of leak through the primary barrier, the liquid tight secondary barrier blocks further leakage of the cryogenic fluid. However, once the secondary barrier is damaged, it is highly possible that the leaked cryogenic fluid flows through the flat joint made of glass wool and reaches the inner hull of the ship. The primary objective of the present study is to investigate the influence of the damage extent in the secondary barrier on the amount of leaked cryogenic fluid reaching the inner hull and the temperature distribution there. Simulation results using a computational fluid dynamics tool were compared with the experimental data for the leaked cryogenic fluid flow and evaporation in the secondary insulation layer.