bluuebunny/crossref_metadata_2025 huggingface dataset:
Teratogenic potential of pholedrine: A sympathomimetic vasoconstrictive drug – A population‐based case‐control study
Authors: Bánhidy Ferenc , Ács Nándor , Puhó Erzsébet H. , Czeizel Andrew E.
Published: February 2010

Pholedrine was a frequently used drug for the treatment of severe hypotension in some countries, including Hungary. The possible teratogenic effect of pholedrine was not checked; therefore; the birth outcomes, particularly congenital abnormalities (CAs), of infants born to women treated with pholedrine during pregnancy, and pregnancy complications were evaluated in the population‐based large dataset of the Hungarian Case‐Control Surveillance System of Congenital Abnormalities. Cases with CA and their matched controls without CA born to mothers with pholedrine use during pregnancy were compared. Of 22 

843 cases and 38 151 controls, 768 (3.4%) and 1509 (4.0%) were born to mothers with pholedrine treatment, respectively (adjusted odds ratios [OR] with 95% CI: 0.9, 0.8–1.0). There was no higher risk for any CA group in the offspring of mothers who used pholedrine during the second and/or third month of pregnancy (i.e. the critical period of most major CA). The mean gestational week at delivery and birthweight was similar in newborns of women with or without pholedrine treatment during pregnancy. The pattern of pregnancy complications was characteristic (lower incidence of preeclampsia/eclampsia, while higher incidence of severe nausea/vomiting and anemia), explained mainly by the underlying maternal hypotension. In conclusion, pholedrine treatment in pregnant women was not associated with a higher risk for CA or other adverse birth outcomes, such as preterm birth or low birthweight. The knowledge of the teratogenic potential of pholedrine may contribute to the evaluation of other sympathomimetic drugs.
Effect of water stress on ten forage grasses native or introduced to Iran
Authors: Bahrani Mohammad Jafar , Bahrami Hossein , Haghighi Ali Akbar Kamgar
Published: February 2010

Water stress is one of the most limiting factors in crop and forage production in semi‐arid and arid regions. In a greenhouse experiment, ten forage grass species native or introduced to Iran were tested under imposed water stress. The experiment followed a 10 (species) × 3 (soil moisture) factorial design in four randomized blocks. The grass species were desert wheatgrass (Agropyron desertorum [Fisch] Schult.), tall wheatgrass (A. elongatum Host Beavu.), smooth bromegrass (Bromus inermis Leyss.), orchardgrass (Dactylis glomerata L.), June wildrye (Elymus junceus Fisch.), tall fescue (Festuca arundinacea Schreb.), perennial ryegrass (Lolium prenne L.), blue panicum (Panicum antidotale Retz.), large canarygrass (Phalaris tuberosa L.) and mountain wildrye (Secale montaneum Guss.). These species were grown in pots at three levels of moisture (23% [control], 17% [moderate] and 14% [severe] on the dry soil weight basis). Increased water stress decreased total water use in all grass species and tended to decrease plant height, leaf water potential, leaf area, water‐use efficiency and root dry weight in all or most species, with varying degrees of reduction among the species. On the contrary, water stress generally had no effects on the root : shoot ratio of the grasses. Based on the reduction in total dry matter production under the two stress levels, tall wheatgrass and smooth bromegrass were the most drought‐tolerant species, while orchardgrass was the most susceptible species.
Effect of adding lactic acid bacteria and molasses on fermentation quality and in vitro ruminal digestion of total mixed ration silage prepared with whole crop rice
Authors: Cao Yang , Takahashi Toshiyoshi , Horiguchi Ken‐ichi , Yoshida Norio
Published: February 2010

This study examined the effects of molasses (M) and lactic acid bacteria (LAB) on the quality of total mixed ration (TMR) silages prepared with whole crop rice (WCR) and tofu cake (TC). Chemical composition, organic acids, and in vitro ruminal digestion were determined. Silages were prepared using a small‐scale system of silage fermentation. Treatments included control silage without additive, or with M (4% fresh matter basis), LAB (5 mg kg−1 fresh mater basis, Lactobacillus plantarum Chikuso‐1), and M+LAB. After 60 days of fermentation, there were no notable differences in chemical composition among treatments. The four silages were of good quality with low pH and NH3‐N, and high lactic acid (LA) and V‐scores. Both LAB and M+LAB silages had more (P = 0.005) LA contents than the control and M silages. Addition of LAB tended to decrease (P = 0.065) ruminal methane production after 6 h in vitro incubation, although DM digestibility, total volatile fatty acids, and the molar concentrations of acetic acid, isovaleric acid, valeric acid, propionic acid, and the acetic : propionic acid ratio were not affected, whereas butyric acid was higher (P = 0.008) with the control than with the other silages. Our results suggest that adding LAB increased the LA content of TMR silage and tended to decrease ruminal methane production, while adding M did not significantly increase the LA content of TMR silage and tended to increase ruminal methane production in vitro.
Automatic Delineation of Capture Zones for Pump and Treat Systems: A Case Study in Piedmont, Italy
Authors: Tosco Tiziana , Di Molfetta Antonio , Sethi Rajandrea
Published: February 2010

The design of a pump and treat (P&T) system for the hydraulic control of a contaminated plume in a confined aquifer is presented here. Being the system designed for the emergency containment of a nonaqueous phase liquid plume, the evaluation of the system’s short‐term efficiency was considered an important issue. For this reason, both time‐related and ultimate capture zones were defined. They were traced using the automatic protection area (APA) model, a capture‐zone delineation tool based on a hybrid forward‐backward particle tracking algorithm, that provides an automatic post‐processing encirclement of capture zones. Two simple indexes are here proposed for the evaluation of the performance of the hydraulic barrier, that is, the efficacy and efficiency indexes, calculated from the capture areas provided by APA. The discharge rates of the wells were dimensioned applying the APA algorithm, maximizing efficacy and efficiency of the barrier. Results proved both visually (via plotting of capture zones) and numerically (via calculation of the indexes) that the P&T system can provide a complete capture of the contaminated area and minimizes the volume of extracted water. Consequently, the APA algorithm was proved to be a useful tool in capture zone delineation. As a future perspective, it could be coupled with the real‐time measurement of pumping rates and water levels and be implemented as a part of a tuning tool for the management of the hydraulic barrier.
Spatial Variation in MTBE Biodegradation Activity of Aquifer Solids Samples Collected in the Vicinity of a Flow‐Through Aerobic Biobarrier
Authors: Lesser Luis E. , Johnson Paul C. , Spinnler Gerard E. , Bruce Cristin L. , Salanitro Joseph P.
Published: February 2010

The spatial variation in methyl tert‐butyl ether (MTBE) biodegradation activity of aquifer solids samples collected in the vicinity of a flow‐through aerobic biobarrier was assessed through use of standard laboratory microcosms. These were prepared by collecting soil cores at a range of locations and depths along different flow paths through the biobarrier. Sections of core samples were placed in sealed bottles with MTBE‐free groundwater from the site. The groundwater was filtered to remove microbes, and sparged with O2. The initial MTBE concentration in the microcosms was adjusted to about 1 mg/L. Biodegradation activity was characterized by the magnitude of MTBE concentration reductions occurred over 4 weeks relative to control microcosms. Sampling locations and depths were selected to allow investigation of relationships between MTBEdegrading activity and dissolved oxygen (DO) concentration, MTBE, soil type, and initial microbial conditions (biostimulated vs. bioaugmented). The results suggest a relatively wide‐spread presence of MTBE‐degrading microbial consortia, with varying levels of MTBE‐degrading activity. Significant changes in activity were observed over 0.3‐m vertical distances in the same location; for example, cores from the most upgradient sampling locations contained sections with no discernible MTBEbiodegradation over 4 weeks, as well as sections that achieved order‐of‐magnitude MTBE concentration reductions within 2 weeks. None of those cores, however, achieved MTBE biodegradation to nondetect levels (<0.005 mg/L), as was observed in some cores from downgradient locations. Cores from the bioaugmented regions had the highest frequency of MTBE biodegradation to nondetect levels among their sections suggesting a direct effect of the inoculum and its distribution when it was implanted. Most cores with no activity were associated with the upgradient, low‐DO, and high‐MTBE concentration field environments, but low‐DO field environments also yielded MTBE‐degrading samples. There were no other clear correlations between MTBE‐degrading activity in the microcosms and the local field environment conditions at the time of sampling.
Probing the α‐Helical Structural Stability of Stapled p53 Peptides: Molecular Dynamics Simulations and Analysis
Authors: Guo Zuojun , Mohanty Udayan , Noehre Justin , Sawyer Tomi K. , Sherman Woody , Krilov Goran
Published: February 2010

Reactivation of the p53 cell apoptosis pathway through inhibition of the p53‐hDM2 interaction is a viable approach to suppress tumor growth in many human cancers and stabilization of the helical structure of synthetic p53 analogs via a hydrocarbon cross‐link (staple) has been found to lead to increased potency and inhibition of protein–protein binding (J. Am. Chem. Soc. 129: 5298). However, details of the structure and dynamic stability of the stapled peptides are not well understood. Here, we use extensive all‐atom molecular dynamics simulations to study a series of stapled α‐helical peptides over a range of temperatures in solution. The peptides are found to exhibit substantial variations in predicted α‐helical propensities that are in good agreement with the experimental observations. In addition, we find significant variation in local structural flexibility of the peptides with the position of the linker, which appears to be more closely related to the observed differences in activity than the absolute α‐helical stability. These simulations provide new insights into the design of α‐helical stapled peptides and the development of potent inhibitors of α‐helical protein–protein interfaces.
Rehabilitation of olfaction post‐laryngectomy: a randomised control trial comparing clinician assisted versus a home practice approach
Authors: Ward E. , Coleman A. , Van As‐Brooks C. , Kerle S.
Published: February 2010

Clin. Otolaryngol. 2010, 35, 39–45.

Objectives:  To determine (i) the prevalence of impaired olfaction in a group of individuals post‐laryngectomy, and (ii) whether intensive, clinician‐supported training of the Nasal Airflow Inducing Manoeuvre (NAIM) was more effective at improving olfactory acuity than intensive, home practice over a 6‐week period.

Designs:  Cohort study followed by a randomised control trial of two treatments over a 6‐week period with a 3‐month review.

Participants:  Olfactory acuity was evaluated in 43 laryngectomy patients. Results revealed 95% had impaired olfactory acuity (anosmic or hyposmic). From this group 40 eligible participants with reduced olfactory acuity were then randomly assigned into either the clinician‐supported or home practice treatment group.

Main outcome measures:  Olfactory acuity and functional impact measures relating to olfactory acuity (participation restriction, wellbeing/distress).

Results:  Although olfactory acuity significantly improved in both treatment groups following 6 weeks of therapy, results indicated significantly greater improvement in the clinician‐assisted group immediately post‐treatment. By 3 months, post‐treatment effects were maintained. Both modes of treatment improved levels of patient wellbeing, however, only the clinician‐assisted mode made a significant positive effect on levels of perceived participation restriction.

Conclusion:  Reduced olfactory acuity is prevalent post‐laryngectomy. Olfactory acuity can be significantly improved using either 6 weeks of clinician‐assisted or home practice using the NAIM manoeuvre, although the current data suggest that intensive clinician‐assisted treatment can assist patients to improve more rapidly and have a positive impact on functional state.
The incidence of epiglottic cysts in a cohort of adults with acute epiglottitis
Authors: Yoon T.M. , Choi J.O. , Lim S.C. , Lee J.K.
Published: February 2010

Clin. Otolaryngol. 2010, 35, 18–24.

Objective:  To evaluate the effects of a coexisting epiglottic cyst on the clinical course and airway management of acute epiglottitis in adults. A review of the airway risk factors were studied in adults with acute epiglottitis in South Korea from 1997 to 2009.

Design:  Retrospective chart review.

Setting:  Academic tertiary care referral medical center.

Participants:  The study included 117 adult patients that were diagnosed with acute epiglottitis laryngoscopically over a period of 12 years. Two distinct groups were identified: one with acute epiglottitis associated with an infected epiglottic cyst (n = 29, 25%) and the other with acute epiglotittis without a cyst (n = 88, 75%).

Main outcome measures:  Patient background data, clinical manifestations, laboratory data, airway management, outcomes, and recurrence were recorded.

Results:  Eight (28%) out of 29 patients with an infected epiglottic cyst required airway intervention compared to the four (5%) out of 88 patients without a cyst. The difference between the two groups was statistically significant (P = 0.001). Five out of six patients with recurrent acute epiglottitis had a coexisting epiglottic cyst. The recurrence of acute epiglottitis in patients with a cyst was significantly more frequent (P = 0.003). Twelve patients (10%) required airway intervention. There was no mortality found in this study. Logistic regression analysis showed that an older age, dyspnoea, a high pulse rate, and the presence of an epiglottic cyst were associated with an increased risk for airway obstruction.

Conclusions:  The results of this study showed that a pre‐existing epiglottic cyst might be associated with a suppurative infection of the supraglottis. Infected epiglottic cysts increased the risk for airway obstruction and recurrence of acute epiglottitis.
The role of psychological distress in laryngopharyngeal reflux patients: a prospective questionnaire study
Authors: Shin K.‐S. , Tae K. , Jeong J.‐H. , Jeong S.‐W. , Kim K.‐R. , Park C.‐W. , Park Y.‐C.
Published: February 2010

Clin. Otolaryngol. 2010, 35, 25–30.

Objectives:  To determine the role of psychological distress in laryngopharyngeal reflux patients and evaluate the correlation between symptoms, laryngeal signs, pH monitoring results and psychological profile.

Design:  Prospective study.

Setting:  Hanyang University Hospital, a university teaching hospital and tertiary referral center.

Participants:  One hundred and six patients who were diagnosed with laryngopharyngeal reflux by 24‐h ambulatory double probe pH monitoring and 119 healthy controls visiting our health promotion center from January 2006 to June 2007.

Main outcome measures:  The psychological profile of laryngopharyngeal reflux patients measured by the Symptom Checklist‐90‐Revised questionnaire were evaluated and compared with those of healthy controls. The correlation between reflux symptom index, reflux finding score, parameters of pH monitoring and the Symptom Checklist‐90‐Revised profiles were also evaluated.

Results:  On the Symptom Checklist‐90‐Revised questionnaire, the total mean T‐scores of the nine symptom dimensions and three global indices of the laryngopharyngeal reflux patients were all below 50. The Global Severity Index, which indicates overall psychological distress, was normal in all of the patients. On comparison with the control group, no statistically significant difference was noted in the psychological profile except on the Somatisation scale where laryngopharyngeal reflux patients showed significantly higher scores. Reflux symptom index showed significant positive correlation with the number of reflux episodes, percentage of time which pH fell below 4 in total positions, and DeMeester score of the upper probe. The nine symptom dimensions and three global indices of Symptom Checklist‐90‐Revised questionnaire did not show any correlation with reflux symptom index, reflux finding score and the parameters of the 24‐h ambulatory double probe pH monitoring.

Conclusions:  Laryngopharyngeal reflux patients did not demonstrate any significant level of psychological distress and their symptom severity showed significant positive correlation with reflux severity.
Association of Acenaphthoporphyrins with Liposomes for the Photodynamic Treatment of Leishmaniasis
Authors: Gardner Daniel M. , Taylor Viviana M. , Cedeño David L. , Padhee Shruti , Robledo Sara M. , Jones Marjorie A. , Lash Timothy D. , Vélez Iván D.
Published: February 2010

Acenaphthoporphyrins are potential photosensitizers for photodynamic therapy, but their hydrophobicity limits their potential. Liposomes have been widely investigated as delivery vehicles that can transport hydrophobic drugs in biological systems. Here we study the association of acenaphthoporphyrins with liposomes made up of dimyristoyl phosphatidylcholine (DMPC), and to liposomes made up of a mixture of DMPC, cholesterol (Chol) and distearoyl phosphatidylglycerol (DSPG) in a 2:1:0.8 molar ratio to evaluate how liposome composition affects association constants. In liposomes consisting only of DMPC, the smaller monoacenaphthoporphyrin had the largest association constant of 5.5 × 104 m−1 while the larger adj‐diacenaphthoporphyrin and opp‐diacenaphthoporphyrin (ODP) had smaller association constants at 1.8 × 104 and 1.5 × 104 m−1, respectively. The addition of liposomal Chol and DSPG has little effect on the magnitudes of the association constants. Polarization studies show that the acenaphthoporphyrins are driven far into the lipid bilayer to minimize polar–nonpolar interactions. Confocal microscopy confirms that the DMPC liposomes transport the porphyrins into promastigotes of Leishmania tarentolae. The compounds associated with DMPC:Chol:DSPG liposomes are effective in vitro against axenic and intracellular amastigotes of the pathogenic Leishmania panamensis. The effectiveness of the compounds is enhanced upon exposure of cultures to visible light.
Saproxylic parasitoid (Hymenoptera, Ichneumonoidea) communities in managed boreal forest landscapes
Authors: STENBACKA FREDRIK , HJÄLTÉN JOAKIM , HILSZCZAŃSKI JACEK , BALL JOHN P. , GIBB HELOISE , JOHANSSON THERESE , PETTERSSON ROGER B. , DANELL KJELL
Published: February 2010

Abstract.  1. Species of higher trophic levels are predicted to be more vulnerable to disturbances (e.g. by forestry) than their prey because of low population densities, extreme specialisation and reliance on intact trophic chains.

2. The aim of this study was to acquire some much‐needed basic information on saproxylic parasitoids in boreal forest landscapes. To obtain reliable estimates of species richness, abundance, assemblage composition and host associations of saproxylic parasitoids in different stand types (clear‐cuts, mature managed forests and old‐growth reserves), we used two different methods (emergence traps and window traps).

3. Window traps caught more species and gave a better measure of the species pool in different stand types, while emergence traps were more suitable for detailed analyses concerning substrate requirements, hatching periods and to some extent host choice.

4. The general distribution pattern revealed no significant differences in species richness among stand types, but parasitoid assemblages were affected by forest successional stage. Idiobionts, dominated by Ontsira antica and Bracon obscurator, preferred clear‐cuts over forested sites, while koinobionts, especially Cosmophorus regius, were more common in mature forests and reserves. We conclude that the stand types studied were complementary in assemblage composition, but that none held a complete assemblage of saproxylic parasitoids and we suggest that a range of successional stages be retained to help conserve the entire parasitoid community.
The role of Loop F in the activation of the GABA receptor
Authors: Khatri Alpa , Weiss David S.
Published: February 2010

Functional studies of the ligand gated ion channel family (nicotinic acetylcholine, serotonin Type 3, glycine and GABA receptors) along with the crystal structure of the acetylcholine binding protein (AChBP) and molecular dynamics simulations of the nAChR structure have resulted in a structural model in which the agonist‐binding pocket comprises six loops (A–F) contributed by adjacent subunits. It is presumed that the binding of agonist results in a local structural rearrangement that is then transduced to the gate, causing the pore to open. Efforts are underway to better define the specific roles of the six binding loops. Several studies have suggested Loop F may play a direct role in linking the structural rearrangement within the binding pocket to the gate, although other investigations have indicated Loop F may be crucial for locking the agonist molecule into the binding site. This review will focus on the controversy surrounding the role of Loop F during GABA receptor activation.
The Transient Response of Imperfect Thin-Walled Stiffened Cylindrical Shell Exposed to Side-On Underwater Explosion
Authors: Hsu Ching-Yu , Jen Chan-Yung
Published: February 2010

The thin-walled stiffened cylindrical shells are usually applied in a submarine which takes the external pressure load, or in a boiler, pressure vessel or pipeline system which takes the internal pressure load. The thin-walled stiffened cylindrical shells under hydrodynamic loading are very sensitive to geometrical imperfections. This study is investigating an imperfect thin-walled stiffened cylindrical shell (out-of-round ratio is ψ = 2%) at a depth of 50m below the water level to see how it withstands sideward TNT 782 kg underwater explosion loading so as to understand its structural transient response. ABAQUS finite element software is used as an analysis tool in the current study, meanwhile, during the analysis process, the Fluid-Structure Interaction (FSI) condition is employed. The structural transient response results of stress and displacement time history of the imperfect thin-walled stiffened cylindrical shell can be used as a reference for the anti-underwater explosion analysis and design of future submersible vehicles, pressure hulls or related structural designs.
Wave-In-Deck Load on a Jacket Platform, CFD-Derived Pressures and Non-Linear Structural Response
Authors: Iwanowski Bogdan , Gladso̸ Rune , Lefranc Marc
Published: February 2010

The paper presents an industrial application of CFD and non-linear structural response codes in offshore technology. A Wave-In-Deck load due to an extreme wave, acting on a jacket platform, is studied numerically. Particular attention is given to details of local flow and local non-linear dynamical response of the structure. A very detailed FEM model of the platform deck structure, composed of shell elements, is embedded into a non body-conforming CFD grid of computational cells. The applied CFD code is a Navier-Stokes equation solver with an improved Volume of Fluid (iVOF) method employed to displace and re-construct fluid’s free surface and uses a simple, Cartesian grid. The two computational grids, FEM and CFD, are independent. The challenge of a direct mapping of CFD-derived fluid pressures onto structural FEM shell elements is addressed. Then the non-linear dynamical response of the structure is found in time domain. The employed CFD code is ComFLOW while the FEM part is handled by the well-known commercial program LS-DYNA. The composed approach utilizes both robustness of VOF-based methods in tracking of the fluid’s free surface and reliability of FEM structural codes such as LS-DYNA.
Residual Strength of a FPSO Vessel After Collision Damages
Authors: Russo M. , Renaud F. , Steen E. , Kippenes J. , Oma N.
Published: February 2010

Because of the larger sizes of modern service vessels, a collision between one of these units and a FPSO may cause severe damages which can threaten the FPSO’s overall hull girder capacity to withstand the operational and environmental loads. The present work addresses these issues by investigating the global residual strength of the hull girder after representative collision damages. The impact on global strength from effects such as the variation in the still water and wave loads due to the flooded condition, local water pressure and top side loads have been evaluated.
Parameter Optimization of Vibration Control System in Multiple DOF Structures
Authors: Li Guixi , Ma Rujian , Luo Xiaobing
Published: February 2010

The parameter optimization and optimal vibration control effects of the multiple tuned mass damper system are studied in this paper by establishing the dynamic model of the multi-mode control of the multi-degree-of-freedom structure and vibration control system. The transfer functions and dynamic magnification factors of the multi-mode control of the multi-degrees-of-freedom structure and vibration control system are derived at first. Then parameter optimization study of the vibration control system was performed, where the minimum of the dynamic magnification factor is used as the optimal objective. Furthermore, the optimal vibration control effects of single mode control and multi-mode control are studied. The application examples are finally given and indicated that this method has the characteristics of better suitability and high accurate.
FPSO and TLWP Interacting at a Reduced Distance for Dry Tree Completion System
Authors: Malta Edgard B. , Rampazzo Fabiano P. , Cruz Roberto E. , de Oliveira Allan C. , Nishimoto Kazuo
Published: February 2010

Nowadays, an offshore industry challenge is developing a floating system with production, storage and offloading capabilities together with a dry tree system reducing costs and maintenance. A solution could be two offshore units working at the same area. The system consists of a unit with dry completion, like a well head platform with drilling and workover facilities, and other capable to produce the oil and gas, and storage them. A better option is to have both units coupled making them work as one. By doing this, it could be reduced the radius of the mooring line footprint and the risk of clashing between the lines and shuttle tankers. The dimensions of the unit with the dry tree could be decreased because some facilities could be allocated at the large unit with storage capacity. The main goal of this paper is show the viability of this innovative system composed by two offshore units. A Tension Leg Wellhead Platform (TLWP) and a Floating Production Storage and Offloading (FPSO) coupled by synthetic ropes and non-symmetrical mooring system. Some comparisons were done between the numerical results from Numerical Offshore Tank (TPN) and physical tests carried out in NMRI (National Maritime Research Institute - JAPAN). The model scale of 1:100 and the numerical model was set up with similar main properties and equivalent lines stiffness. The models were exposed to extreme wave conditions for some incidences. Besides that, regular wave and current analyses were generated as well.
Vibration Load Identification of Offshore Platforms Based on Neural Network
Authors: Ma Rujian , Li Guixi , Lin Jianshan
Published: February 2010

The vibration load identification was performed in this paper, where the neural network is introduced in order to overcome the disadvantages of the commonly used method. The first step is to establish a finite element model of the platform using ANSYS software. The training data of neural network is obtained by applying simulation to get response at the identification point of the model. The neural network model of the platform is then set up. The network is trained until the convergence state by using the above data. Finally, the vibration load identification for W12-1 oil production platform is performed using the method, where the measured response data are inputted to the trained network and the identification loads of the platform are obtained. The results indicate that there are more advantages of the method as compared with commonly used load identification method when used for such large and complex structures as offshore platforms and the identification accuracy of the method is satisfactory.
Float-Over at High Air Gap Design and Issues
Authors: Cholley Jean-Marc , Delage B. , Cahay M.
Published: February 2010

There is a long history of successful deck installation by float-over deck method: it has been in use as an effective installation method since the seventies. The concept offers the advantage of significant savings in transportation and installation cost by minimizing the installation time and offshore hook-up and eliminating the need for a heavy lift derrick barge. The method was developed for, and has found wide applicability to deck requiring a relatively low air gap. To allow the float-over method to be extended to harsher environmental areas, several new solutions, which are applicable to platforms requiring air gaps of 20m (66ft) or more, have been developed. This paper describes the technologies used today for deck installation at high air gap and analyzes the strength, weaknesses, opportunities and threats of each of these float-over technologies by an overview of the main issues related to: - Installation concept (Ballasting vs. elevating system). - Transportation method. - Environmental conditions. The design, fabrication and operation of the different solutions will be discussed in this paper. To allow the float-over method to be safely extended to more remote exposed field location understanding the issues associated with the different designs presented in this paper will become important.
Study on Judgment Criterion for Cancellation of Ferries Due to Ship Motion and Coastal Wave Data
Authors: Terada Daisuke , Sasa Kenji
Published: February 2010

In this study, from the viewpoint of ship safety and cargo management, examination of a criterion of judgment of ferry cancellation is carried out, based on both observed ship motion when encountering a typhoon and on coastal wave data at that time. Ship motion was observed using a 5,000GT-type ferryboat. As the wave data, coastal waves that were recorded with Nationwide Ocean Wave information network for Ports and HArbourS (NOWPHAS) instead of the encounter waves that are very difficult to measure are used. These data are analyzed by Spectral Analysis based on Auto Regressive (AR) modeling procedure, and the characteristics are analyzed in detail. Moreover, numerical reproductions of ship motion based on observed coastal waves are performed, and some future problems with respect to the decision on the criterion of judging of ferry cancellation are considered.
Modal Identification Applied to Dynamic Positioning
Authors: Santiago Alexandre A. , Costa Ramon R. , Fernandes Antonio C.
Published: February 2010

This work addresses the dynamic positioning response with respect to the environmental disturbances caused by wave, wind, and current effects. Concerning the first and second order wave effects, only the latter may be rejected by the closed loop system. On the other hand, the rejection of first order oscillatory motion causes the so called propeller control signal modulation, which means an earlier and more intensive mechanical wear and tear and higher fuel consumption. The fundamental issue in the dynamic positioning design consists of minimizing the propulsion modulation by filtering out this first order wave effect, which contaminates the controller input measurement. It is worth to mention that the wave spectrum is time varying, with an autocorrelation time of about three hours. This non-stationary behavior has led the work to develop a filtering algorithm which is adaptive with respect to the time varying sea state condition. Therefore, it is highly desirable that the dynamic positioning control system be robust, by having an adaptive behavior with respect to the environmental disturbances and by tracking the wave spectrum parameters. This paper presents a novel algorithm for tracking the modal frequency of the surge, sway, and yaw response spectra, which automatically tunes the first order wave effect filter of a DP system. The proposed name for the technique is modal identification applied to dynamic positioning.
Experimental Investigation of Local Scour Around a Submerged Vertical Circular Cylinder in Steady Currents
Authors: Zhao Ming , Cheng Liang , Zang Zhipeng
Published: February 2010

Local scour around a submerged vertical circular cylinder in steady currents was studied by laboratory experiments. The experiments were conducted under live-bed scour conditions. Only one median sediment size of d50 = 0.40 mm was used in the experiments with a uniformity parameter of d85/d15 = 1.42. In some of the tests, time-developments of scour depth at the stagnation point of the cylinder were measured using the conductivity scour probes. Three-dimensional (3D) seabed topography around each model cylinder was measured using a laser profiler developed at University of Western Australia. The experimental results showed that the scour depth increased with an increase in cylinder height. The development rate of scour depth increases if Shields parameter increases.
A New Double Barrier Tank for Transportation and Storage of LNG
Authors: Bergan Pa˚l G. , Bakken Ka˚re , Sele Arne , Sipila¨ Ari , Russo Massimiliano , Notaro Gabriele
Published: February 2010

There is presently a growing demand for natural gas as a relatively clean energy resource. Major gas reservoirs are often located far away from the major consumer markets; the need for safe end efficient transport across the oceans is growing rapidly. The preferred way of storing and transporting gas from gas fields that are not connected with pipe lines is by way of cooling down the gas to liquid state (LNG), storing it in insulated tanks, transporting it onboard ships, and unloading it at terminals. Recently there has also been an interest in offshore production of LNG onboard fixed or floating platforms or on floating production ships. Good technical solutions for storage of LNG has been available for decades, but there has recently been a growing need for tanks that are suited for transportation very large ships as well as suited for offshore storage and capable of dealing with partial degrees of filling during dynamic, floating conditions. The paper describes an entirely new concept for prismatic LNG containments that is scalable and thereby suited for small as well as very large tanks, it can effectively deal with the sloshing problem during partial filling and dynamic conditions, it has a double barrier for safety, and it is self carrying without need for lateral support structures. The paper describes the conceptual ideas on which this tank is based and outlines some of the structural principles ensuring a safe design. More specifically, this performance is demonstrated through examples of analyses performed. Results from numerical analyses are presented and discussed. The safety concept and the overall performance this new tank concepts meets the requirements specified in IMO’s gas code and has been accepted as an independent tank type A according to IMO International Gas Code.
Assessment of Cryogenic Fatigue Strength of MARK-III LNG Carrier Insulation System
Authors: Kim Myung Hyun , Kil Yoon Pyo , Chun Min Sung , Suh Yong Suk , Kim Wha Soo , Noh Byung Jae , Lee Jae Myung , Yoon Jang Ho , Kim Min Soo , Urm Hang Sub
Published: February 2010

The importance of dynamic strength characteristics of LNG cargo containment system, various research efforts including dry-drop and wet-drop tests as well as sloshing test have been carried out by GTT, shipyards, oil companies, universities as well as classification societies. However, no explicit consideration with regard to the structural performance of insulation system toward the cryogenic environment is yet given. Besides only limited information regarding experimental procedure and analysis results is shared among stakeholders, and it acts as obstacles for the development of consistent CCS (Cargo Containment System) design criteria in an effective manner. Demand for LNG carriers with increased capacity requires further development of the design technology for LNG cargo tanks to meet the safety requirements due to the larger size LNG tanks. In this study, a systematic experimental research is required for the assessment of fatigue strength at cryogenic environment as well as impact strength of insulation system. The different sized mastic support has been adopted to compare the cryogenic fatigue performance. One of the main challenges in this work is to generalize the test results for use in case of other mastic support sizes. The aim of the study is to investigate the typical failure mode and obtain the S-N data under cryogenic fatigue loading. This study will be used as a fundamental study for the cryogenic fatigue assessment for the LNGC insulation system as well as a design guideline. The fatigue tests of Mark-III insulation system are carried out at room temperature and cryogenic temperature, and considered sloshing effect (R = −10). The load levels have been determined based on ultimate strength of reinforced polyurethane foam 12.2bar.
Analysis on Low Frequency Heave, Roll and Pitch Motions of a Deepwater Semisubmersible
Authors: Xiao Longfei , Yang Jianmin , Yang Lijun , Lu Haining
Published: February 2010

Low frequency heave, roll and pitch motions of a semisubmersible should be evaluated carefully, since the air gap and the drilling operation are affected directly. A drilling semisubmersible in operating and survival conditions is investigated numerically and experimentally. Results of RAOs, power spectrums and statistic values are presented and analyzed. Viscous forces are significant for roll and pitch but negligible for heave. The natural periods of roll and pitch are relatively large and low frequency response exists due to excitations by the second order wave drift force. By comparison with the wave frequency response, the low frequency roll and pitch are dominative in operating condition and the same magnitude in survival condition. For heave motion, the low frequency response doesn’t exist in survival storm with long wave periods and exists obviously in operational storm with short wave periods. The effect of wind spectrum is small for heave but very significant for roll and pitch. The low frequency roll and pitch in wind spectrum are much larger than ones in steady wind. It indicated that the resonant roll and pitch induced by the slowly varying wind drift force are much larger than ones induced by the wave drift force.
WindFloat: A Floating Foundation for Offshore Wind Turbines—Part III: Structural Analysis
Authors: Aubault Alexia , Cermelli Christian , Roddier Dominique
Published: February 2010

WindFloat is a floating foundation for large offshore wind turbines. This paper describes the structural engineering that was performed as part of the feasibility study conducted for qualification of the technology. Specifically, the preliminary scantling is described and the strength and fatigue analysis methodologies are explained, focusing on the following aspects: • the coupling between the wind turbine and the hull; • the interface between the hydrodynamic loading and the structural response. Prior to reading this manuscript, the reader is strongly encouraged to read the related paper, which focuses on the design basis for the WindFloat, and explores the requirements that must be addressed by the design teams in this new field. An additional paper in this series describes the hydrodynamic analysis and experimental validations.
Comparison Between a Fatigue Model for Voyage Planning and Measurements of a Container Vessel
Authors: Mao Wengang , Ringsberg Jonas W. , Rychlik Igor , Storhaug Gaute
Published: February 2010

This paper presents results from an ongoing research project which aims at developing a numerical tool for route planning of container ships. The objective with the tool is to be able to schedule a route that causes minimum fatigue damage to a vessel before it leaves port. Therefore a new simple fatigue estimation model, only using encountered significant wave height, is proposed for predicting fatigue accumulation of a vessel during a voyage. The formulation of the model is developed based on narrow-band approximation. The significant response height hs, is shown to have a linear relationship with its encountered significant wave height Hs. The zero up-crossing response frequency fz, is represented as the corresponding encountered wave frequency and is expressed as a function of Hs. The capacity and accuracy of the model is illustrated by application on one container vessel’s fatigue damage accumulation, for different voyages, operating in the North Atlantic during 2008. For this vessel, all the necessary data needed in the fatigue model, and for verification of it, was obtained by measurements. The results from the proposed fatigue model are compared with the well-known and accurate rain-flow estimation. The conclusion is that the estimations made using the current fatigue model agree well with the rain-flow method for almost all of the voyages.
Model Studies on Spar Platform With 5MW Wind Turbine
Authors: Seebai T. , Sundaravadivelu R. , Vendhan C. P.
Published: February 2010

This paper presents the model study on the spar platform designed to support 5MW wind turbine in 300m water depth. The diameter of the Spar is 16m, draft is 90m and freeboard is 10m. A 1:100 scale model of the spar is studied in the wave basin. The effect of circular disc of diameter 24m at the bottom of the spar on the heave and surge at the top of the wind tower is reported for the wave height of about 6m and wave period in the range of 6s to 28s, whereas the prototype wave period range is from 6s to 18s.
Effects of Welding Residual Stresses on High Tensile Steel Plate Ultimate Strength: Nonlinear Finite Element Method Investigations
Authors: Paik Jeom Kee , Sohn Jung Min
Published: February 2010

The primary objective of the present paper is to examine the effects of welding residual stresses on ultimate strength of high tensile steel plates under axial compression in terms of their magnitude and pattern. The ANSYS nonlinear finite element method is employed for the purpose. The secondary objective of the present paper is to study a nonlinear finite element method modeling technique for welded plate structures with residual stresses. Three levels of residual stresses, namely slight, average and severe levels are considered. As another important parameter of influence on the plate ultimate strength, the plate thickness is also varied in the numerical computations to examine their role and trend. Important insights and conclusions developed from the present study are documented.
On Buckling Collapse of a Fusion-Welded Aluminum-Stiffened Plate Structure: Experimental and Numerical Studies
Authors: Paik Jeom Kee , Kim Bong Ju , Sohn Jung Min , Kim Sung Hoon , Jeong Jae Min , Park June Seok
Published: February 2010

The primary objective of the present paper is to experimentally examine buckling collapse characteristics of fusion welded aluminum-stiffened plate structures under axial compression until and after the ultimate limit state is reached. The secondary objective of the paper is to study a nonlinear finite element method modeling technique for computing the ultimate strength behavior of welded aluminum structures. A set of aluminum-stiffened plate structures fabricated by gas metal arc welding (GMAW) is studied. The test structure is equivalent to a full scale deck structure of an 80m long high speed vessel. Plate part of the structures is made of 5383-H116 aluminum alloy while extruded stiffeners are made of 5083-H112 aluminum alloy. Welding induced initial imperfections such as plate initial deflection, column type global initial deflection of stiffeners, sideways initial distortion of stiffeners, welding residual stresses, and softening in the heat-affected zone are measured. The ANSYS nonlinear finite element method is employed for the numerical computations of the test structure’s ultimate strength behavior by a comparison with experimental data. Insights and conclusions developed from the present study are documented.
The Analysis of Mooring Systems of a Drillship
Authors: Ma Gang , Sun Liping , Wang Hongwei
Published: February 2010

In this paper the mooring system of a drill ship is analyzed which is designed for South China Sea in 1500 meters depth. The analyses of the mooring lines have been developed based on the theories dealing with slender structure and cables, so the elastic rod theory is used. Elastic rod theory is developed for the analysis of line dynamics. The governing equations of mooring lines and risers are treated in the global coordinate system without transforming the coordinate system. The hydrodynamic forces on the lines together with the strain and the stress of the structures caused by geometric nonlinearity are considered. The model of the rods allows for a small elongation, and permits large deflections and finite rotations. The rods are of elasticity and arbitrary configuration, with kind of loads and tension variation along its length acting on it, including the motion of rod, hydrodynamic force resulted from the external fluid and gravity. The fluid in the riser is considered for riser analysis, and the support of the sea bottom is presented for mooring line analysis. Finite element method is used to discrete mooring lines and risers, and lines dynamic analysis is executed with time integration method. A program is developed, and its validation is checked by comparison of numerical results to exact solutions for a nonlinear, static problem. Both static analysis and dynamic analysis of the whole system are done to ensure the mooring system of the drilling ship on 1500m depth can successfully applied.
Reliability Analysis of Compliant Offshore Tower Under Earthquake Loads
Authors: Hasan Syed Danish , Islam Nazrul , Moin Khalid
Published: February 2010

Articulated offshore tower with universal joints in the intermediate level leads to a multi-hinged configuration that can be used for a variety of deep water application. They are flexibly linked to the sea-bed by a universal joint and comply with the oscillatory environmental loads causing large fluctuating seismic demands at the articulating joints. This paper investigates the dynamic response and the reliability assessment of articulated joint (s) of such structures under seismic sea environment. The analysis includes the influence of sea bed shaking on the water-particle kinematics by using Californian earthquakes. The sea state is characterized by DNV version of Pierson Moskowitz spectrum. The dynamic equation of motion is derived using Lagrangian approach, taking into the account the nonlinearities associated with structure and loads. A limit-state function for seismic demand for a universal joint has been derived. Using the derived limit-state function and the responses obtained after time-domain seismic analysis, reliability assessment of the articulated joint has been carried out, using efficient MPP-based probabilistic methods. Design point, important for probabilistic design of articulated joint, located on the failure surface has been worked out. Stochastic sensitivity analysis has been performed to assess the relative importance of design parameter on the stochastic response of articulated joint.