bluuebunny/crossref_metadata_2025 huggingface dataset:
Is fat content of human milk decreased by infusion?
Authors: Igawa Mio , Murase Masahiko , Mizuno Katsumi , Itabashi Kazuo
Published: November 2013

Background

Human milk (HM) is the optimum nutrition for preterm infants. Previous studies showed that tube infusion decreased the fat content in thawed HM. The aim of this study was to determine if freezing–thawing is the main reason for decrease of fat content. In neonatal intensive care units, thawed HM is used in general, therefore the aim of this study was to investigate fat loss during tube infusion with regard to changes in tube size, material, and infusion rate.

Methods

First, pre‐infusion and post‐infusion fat content was measured in 15 fresh HM, 10 thawed HM and 6 formula samples. We compared post‐infusion and pre‐infusion fat content as well as the percent decrease in fat concentration among fresh HM, thawed HM and formula samples. Second, we measured the fat content of 160 thawed HM samples infused via four different diameters (3–6 Fr), two types of material (DEHP‐free and PVC‐free), and two infusion rates (30 or 60 min). We compared the percent decrease in fat concentration among four different tube sizes, between DEHP‐free and PVC‐free tubes, and between 30 and 60 min infusion durations.

Results

Post‐infusion fat content was significantly decreased compared to before infusion in thawed HM and fresh HM but not in formula. Given that thawed HM resulted in larger decrease in fat content, we performed a second experiment and found no difference regarding differing size, materials or infusion rate.

Conclusions

There was a far greater decrease in the post‐infusion fat content of thawed HM compared to fresh HM under all test conditions.
Molecular diagnosis of mitochondrial respiratory chain disorders in Japan: Focusing on mitochondrial DNA depletion syndrome
Authors: Yamazaki Taro , Murayama Kei , Compton Alison G , Sugiana Canny , Harashima Hiroko , Amemiya Shin , Ajima Masami , Tsuruoka Tomoko , Fujinami Ayako , Kawachi Emi , Kurashige Yoshiko , Matsushita Kenshi , Wakiguchi Hiroshi , Mori Masato , Iwasa Hiroyasu , Okazaki Yasushi , Thorburn David R , Ohtake Akira
Published: November 2013

Background

Although mitochondrial respiratory chain disorders (MRCD) are one of the most common congenital metabolic diseases, there is no cumulative data on enzymatic diagnosis and clinical manifestation for MRCD in Japan and Asia.

Methods

We evaluated 675 Japanese patients having profound lactic acidemia, or patients having symptoms or signs of multiple‐organ origin simultaneously without lactic acidemia on respiratory chain enzyme activity assay and blue native polyacrylamide gel electrophoresis. Quantitative polymerase chain reaction was used to diagnose mitochondrial DNA depletion syndrome (MTDPS). Mutation analysis of several genes responsible for MTDPS was also performed.

Results

A total of 232 patients were diagnosed with a probable or definite MRCD. MRCD are common, afflicting one in every several thousand people in Japan. More than one in 10 of the patients diagnosed lacked lactic acidemia. A subsequent analysis of the causative genes of MTDPS identified novel mutations in six of the patients. A 335 bp deletion in deoxyguanosine kinase (DGUOK; g.11692_12026del335 (p.A48fsX90)) was noted in two unrelated families, and may therefore be a common mutation in Japanese people. The proportion of all patients with MTDPS, and particularly those with recessive DNA polymerase γ (POLG) mutations, appears to be lower in Japan than in other studies. This is most likely due to the relatively high prevalence of ancient European POLG mutations in Caucasian populations. No other significant differences were identified in a comparison of the enzymatic diagnoses, disease classifications or prognoses in Japanese and Caucasian patients with MRCD.

Conclusion

MTDPS and other MRCD are common, but serious, diseases that occur across all races.
Variance Estimation and Asymptotic Confidence Bands for the Mean Estimator of Sampled Functional Data with High Entropy Unequal Probability Sampling Designs
Authors: Cardot Hervé , Goga Camelia , Lardin Pauline
Published: November 2013

For fixed size sampling designs with high entropy, it is well known that the variance of the Horvitz–Thompson estimator can be approximated by the Hájek formula. The interest of this asymptotic variance approximation is that it only involves the first order inclusion probabilities of the statistical units. We extend this variance formula when the variable under study is functional, and we prove, under general conditions on the regularity of the individual trajectories and the sampling design, that we can get a uniformly convergent estimator of the variance function of the Horvitz–Thompson estimator of the mean function. Rates of convergence to the true variance function are given for the rejective sampling. We deduce, under conditions on the entropy of the sampling design, that it is possible to build confidence bands whose coverage is asymptotically the desired one via simulation of Gaussian processes with variance function given by the Hájek formula. Finally, the accuracy of the proposed variance estimator is evaluated on samples of electricity consumption data measured every half an hour over a period of 1 week.
Histological skin morphology enhancement base on molecular hyperspectral imaging technology
Authors: Li Q. , Sun Z. , Wang Y. , Liu H. , Guo F. , Zhu J.
Published: November 2013

Background

Most traditional skin histological analysis methods are based on the light microscopy images, which can only provide limited information and low contrast results for pathology evaluation. Molecular hyperspectral imaging technology can provide both spatial and spectral information of skin sections, which is a new method for histological skin analysis.

Methods

The molecular hyperspectral imaging system was developed by coupling an acousto‐optic tunable filters adapter to microscopy and the molecular hyperspectral images were analyzed by home‐written software with image processing algorithms. Then, the histological structures in skin sections were investigated in several locations to evaluate the potential application of the molecular hyperspectral imaging technique to dermatology.

Results

Molecular hyperspectral images of skin sections were obtained. Single‐band images, false color images, virtual 3D surface view images, and color‐coded spectral clustering results were produced to highlight the skin structures for histological evaluation.

Conclusion

Unlike traditional histological analysis with light microscopy, the molecular hyperspectral imaging technology can enhance the visualization of skin structures using their spectral signatures and their gray values. This technology has potential for the diagnosis and histopathologic characterization of different kind of skin cells.
Japanese Causatives are Not Relevant To Lexical Integrity
Authors: Ackema Peter
Published: November 2013

Productive Japanese causative verbs appear to form a problem for the idea that the relation between morphology and syntax is characterised by lexical integrity, meaning that the internal structure of complex words is opaque to syntax. This is because such causatives show behaviour that indicates the verb and the causative morpheme head separate syntactic clauses underlyingly, so their structure must be syntactically transparent, but nevertheless the combination of verb and causative morpheme seems to be a morphological complex. In this paper I argue that, given a modular architecture of grammar, the module in which verb and causative morpheme might be argued to be a complex word is morpho‐phonology, which is not the module to which lexical integrity pertains. In the module to which this does pertain, morpho‐syntax, the productive causative morpheme is a free morpheme, rather than an affix, at all levels of representation. The construction is therefore not relevant to the question of whether or not lexical integrity holds. The paper concludes with a discussion of the relationship between the productive causative and the ‘lexical’ causative, which arguably does involve a morphological complex in morpho‐syntax as well as morpho‐phonology. It is argued that the occurrence of the same morpheme in syntactic causatives and some lexical causatives does not imperil its status as a free morpheme in the syntactic causative.
An in vitro system for the rapid functional characterization of genes involved in carotenoid biosynthesis and accumulation
Authors: Bai Chao , Rivera Sol M. , Medina Vicente , Alves Rui , Vilaprinyo Ester , Sorribas Albert , Canela Ramon , Capell Teresa , Sandmann Gerhard , Christou Paul , Zhu Changfu
Published: November 2013

We have developed an assay based on rice embryogenic callus for rapid functional characterization of metabolic genes. We validated the assay using a selection of well‐characterized genes with known functions in the carotenoid biosynthesis pathway, allowing rapid visual screening of callus phenotypes based on tissue color. We then used the system to identify the functions of two uncharacterized genes: a chemically synthesized β–carotene ketolase gene optimized for maize codon usage, and a wild‐type Arabidopsis thaliana ortholog of the cauliflower Orange gene. In contrast to previous reports (Lopez, A.B., Van Eck, J., Conlin, B.J., Paolillo, D.J., O'Neill, J. and Li, L. () J. Exp. Bot. 59, 213–223; Lu, S., Van Eck, J., Zhou, X., Lopez, A.B., O'Halloran, D.M., Cosman, K.M., Conlin, B.J., Paolillo, D.J., Garvin, D.F., Vrebalov, J., Kochian, L.V., Küpper, H., Earle, E.D., Cao, J. and Li, L. () Plant Cell 18, 3594–3605), we found that the wild‐type Orange allele was sufficient to induce chromoplast differentiation. We also found that chromoplast differentiation was induced by increasing the availability of precursors and thus driving flux through the pathway, even in the absence of Orange. Remarkably, we found that diverse endosperm‐specific promoters were highly active in rice callus despite their restricted activity in mature plants. Our callus system provides a unique opportunity to predict the effect of metabolic engineering in complex pathways, and provides a starting point for quantitative modeling and the rational design of engineering strategies using synthetic biology. We discuss the impact of our data on analysis and engineering of the carotenoid biosynthesis pathway.
ABC1K1/PGR6 kinase: a regulatory link between photosynthetic activity and chloroplast metabolism
Authors: Martinis Jacopo , Glauser Gaétan , Valimareanu Sergiu , Stettler Michaela , Zeeman Samuel C. , Yamamoto Hiroshi , Shikanai Toshiharu , Kessler Felix
Published: November 2013

Arabidopsis proton gradient regulation (pgr) mutants have high chlorophyll fluorescence and reduced non‐photochemical quenching (NPQ) caused by defects in photosynthetic electron transport. Here, we identify PGR6 as the chloroplast lipid droplet (plastoglobule, PG) kinase ABC1K1 (activity of bc1 complex kinase 1). The members of the ABC1/ADCK/UbiB family of atypical kinases regulate ubiquinone synthesis in bacteria and mitochondria, and impact various metabolic pathways in plant chloroplasts. Here, we demonstrate that abc1k1 has a unique photosynthetic and metabolic phenotype that is distinct from that of the abc1k3 homolog. The abc1k1/pgr6 single mutant is specifically deficient in the electron carrier plastoquinone, as well as in β–carotene and the xanthophyll lutein, and is defective in membrane antioxidant tocopherol metabolism. After 2 days of continuous high light stress, abc1k1/pgr6 plants suffer extensive photosynthetic and metabolic perturbations, strongly affecting carbohydrate metabolism. Remarkably, however, the mutant acclimates to high light after 7 days together with a recovery of carotenoid levels and a drastic alteration in the starch‐to‐sucrose ratio. Moreover, ABC1K1 behaves as an active kinase and phosphorylates VTE1, a key enzyme of tocopherol (vitamin E) metabolism in vitro. Our results indicate that the ABC1K1 kinase constitutes a new type of regulatory link between photosynthetic activity and chloroplast metabolism.
EVALUATION OF DIAPHRAGMATIC MOTION IN NORMAL AND DIAPHRAGMATIC PARALYZED DOGS USING M‐MODE ULTRASONOGRAPHY
Authors: Choi Mihyun , Lee Namsoon , Kim Ahyoung , Keh Seoyeon , Lee Jinsoo , Kim Hyunwook , Choi Mincheol
Published: November 2013

Diagnosis of unilateral diaphragmatic paralysis in dogs is currently based on fluoroscopic detection of unequal movement between the crura. Bilateral paralysis may be more difficult to confirm with fluoroscopy because diaphragmatic movement is sometimes produced by compensatory abdominal muscle contractions. The purpose of this study was to develop a new method to evaluate diaphragmatic movement using M‐mode ultrasonography and to describe findings for normal and diaphragmatic paralyzed dogs. Fifty‐five clinically normal dogs and two dogs with diaphragmatic paralysis were recruited. Thoracic radiographs were acquired for all dogs and fluoroscopy studies were also acquired for clinically affected dogs. Two observers independently measured diaphragmatic direction of motion and amplitude of excursion using M‐mode ultrasonography for dogs meeting study inclusion criteria. Eight of the clinically normal dogs were excluded due to abnormal thoracic radiographic findings. For the remaining normal dogs, the lower limit values of diaphragmatic excursion were 2.85–2.98 mm during normal breathing. One dog with bilateral diaphragmatic paralysis showed paradoxical movement of both crura at the end of inspiration. One dog with unilateral diaphragmatic paralysis had diaphragmatic excursion values of 2.00 ± 0.42 mm on the left side and 4.05 ± 1.48 mm on the right side. The difference between left and right diaphragmatic excursion values was 55%. Findings indicated that M‐mode ultrasonography is a relatively simple and objective method for measuring diaphragmatic movement in dogs. Future studies are needed in a larger number of dogs with diaphragmatic paralysis to determine the diagnostic sensitivity of this promising new technique.
Risk-Based Operations Assessment of a Multilayered Vessel Under Cyclic Loading Conditions
Authors: Zhao Mingxin , Parkinson Richard
Published: November 2013

Operational risks have been evaluated for a multilayered vessel through the fitness-for-service (FFS) assessment. The vessel has been in service for more than four decades and is subjected to cyclic mechanical and thermal loads during normal operations. Leakage has been found over the years by inspections, which led to safety concerns for continued operation. FFS assessment was used to evaluate the condition of the vessel to determine if the vessel was fit for continued operation and the associated risks for a catastrophic type failure or burst of all layers of the vessel. Finite element analysis and fatigue evaluation, with associated partial probability, were conducted for the assessment. The operational risks were evaluated on the combined basis of FFS assessment results, failure modes, and field inspection findings. It was concluded that, despite of the problems found during inspections, risks for the catastrophic type failure of the multilayered vessel are very low and continued operation with appropriate monitoring and maintenance is recommended.
“Adult” Robot Enabled Learning Process in High Precision Assembly Automation
Authors: Cheng Hongtai , Chen Heping
Published: November 2013

Typical robot teaching performed by operators in industrial robot applications increases the operational cost and reduces the manufacturing efficiency. In this paper, an “adult” robot enabled learning method is proposed to solve such teaching problem. This method uses an “adult” robot with advanced sensing and decision-making capabilities to teach “child” robots in manufacturing automation. A Markov Decision Process (MDP) which aims to correct the “child” robot's tool position is formulated and solved using Q-Learning. The proposed algorithm was tested using a mobile robot platform with an in-hand camera (adult) to teach an industrial robot (child) to perform a high accuracy peg-in-hole process. The experimental results demonstrate very robust and stable performance. Because the calibration between the “adult” and “child” robots is eliminated, the flexibility of the proposed method is greatly increased. Hence it can be easily applied in industrial applications where a robot with limited sensing capabilities is installed.
Using Hydrogen as Gas Turbine Fuel: Premixed Versus Diffusive Flame Combustors
Authors: Gazzani Matteo , Chiesa Paolo , Martelli Emanuele , Sigali Stefano , Brunetti Iarno
Published: November 2013

This work aims at estimating the efficiency gain resulting from using lean premixed combustors in hydrogen-fired combined cycles with respect to diffusive flame combustors with significant inert dilution to limit NOx emissions. The analysis is carried out by considering a hydrogen-fired, specifically tailored gas turbine whose features are representative of a state-of-the-art natural gas–fired F-class gas turbine. The comparison between diffusion flame and lean premixed combustion is carried out considering nitrogen and steam as diluents, as well as different stoichiometric flame temperatures and pressure drops. Results show that the adoption of lean premixed combustors allows us to significantly reduce the efficiency decay resulting from inert dilution. Combined cycle efficiency slightly reduces from 58.5%–57.9% when combustor pressure drops vary in the range 3%–10%. Such efficiency values are comparatively higher than those achieved by diffusive flame combustor with inert dilution. Finally, the study investigated the effects of decreasing the maximum operating blade temperature so as to cope with possible degradation mechanisms induced by hydrogen combustion.
A General Approach for Rectified Mass Diffusion of Gas Bubbles in Liquids Under Acoustic Excitation
Authors: Zhang Yuning , Li Shengcai
Published: November 2013

Rectified mass diffusion serves as an important mechanism for dissolution or growth of gas bubbles under acoustic excitation with many applications in acoustical, chemical and biomedical engineering. In this paper, a general approach for predicting rectified mass diffusion phenomenon is proposed based on the equation of bubble motion with liquid compressibility. Nonuniform pressure inside gas bubbles is considered in the approach through employing a well-established framework relating with thermal effects during gas bubble oscillations. Energy dissipation mechanisms (i.e., viscous, thermal, and acoustic dissipation) and surface tension are also included in the approach. Comparing with previous analytical investigations, present approach mainly improves the predictions of rectified mass diffusion in the regions far above resonance and regions with frequencies megahertz and above. Mechanisms for the improvements are shown and discussed together with valid regions and limitations of present approach.
Mixing and Heat Transfer Enhancement in Microchannels Containing Converging-Diverging Passages
Authors: Yong J. Q. , Teo C. J.
Published: November 2013

Fully-developed flow and heat transfer in periodic converging-diverging channels with rectangular cross sections are studied using computational fluid dynamics (CFD) simulations for Reynolds numbers ranging from 50 to 200. Experimental laser sheet flow visualizations have also been utilized with the aid of an enlarged transparent Perspex model, which serves as a form of secondary verification of the CFD results. The CFD investigations focus on two principal configurations of converging-diverging channels, namely the constant curvature and sinusoidal converging-diverging channel. Heat transfer simulations have been carried out under constant wall temperature conditions using liquid water as the coolant. It is found that due to the fluid mixing arising from a pair of recirculating vortices in the converging-diverging channels, the heat transfer performance is always significantly more superior to that of straight channels with the same average cross sections; at the same time the pressure drop penalty of the converging-diverging channels can be much smaller than the heat transfer enhancement. The effects of channel aspect ratio and amplitude of the converging-diverging profiles have been systematically investigated. The results show that for a steady flow, the flow pattern is generally characterized by the formation of a pair of symmetrical recirculating vortices in the two furrows of the converging-diverging channel. Both the optimal aspect ratio and channel amplitude are being presented with the support of CFD analyses. Experimental flow visualizations have also been utilized and it was found that the experimental results agrees favorably with the CFD results. The present study shows that these converging-diverging channels have prominent advantages over straight channels. The most superior configuration considered in this paper has been found to yield an improvement of up to 60% in terms of the overall thermal-hydraulic performance compared to microchannels with straight walls, thus serving as promising candidates for incorporation into efficient heat transfer devices.
A Case Study: Construction of Bucket Foundations for Jackup Ships
Authors: Qiu Gang , Hamann Thorben , Grabe Jürgen , Hein Christian , Howe Robert
Published: November 2013

Jackup ships are built to transport wind turbines foundation between offshore logistics center and the installation site. It require sufficiently stable seabed next to quay walls. Otherwise jackup processes may reduce the stability of the quay wall and remained footprints of the legs could induce unsafe jackup procedures in the future. Foundations have been planned to improve the strength of seabed in front of the quay wall. The numerical analyses of the penetration/extraction processes of the legs into/out of the foundations were presented in OMAE2011-49928 to study the bearing capacity of two foundation designs (open-ended cylinder and bucket foundation).

In consequence of the numerical studies, the bucket foundation was selected and was improved by reduction the height of the foundations and adjust the inclination of the inner wall to reduce the construction costs. Four bucket foundations have been built in Bremerhaven, Germany. This paper provided of a resume of design, construction and set-up process. The penetration and extraction processes of the jackup legs were tested the results were compared with the numerical predictions.
Reliability Based Deep Water Spool Piece Design
Authors: Juluri Naresh , Dib Elie , el-Gebaly Sherif , Cooper Philip
Published: November 2013

Long spools are often required to absorb the end expansion of deep water high pressure and high temperature flowlines. These spools typically have significant metrology and fabrication tolerances. Metrology and spool fabrication tolerances lead to misalignments at the connector hub face. Residual loads then arise from spool deformation due to the installation forces that are required to match-up the connector faces.

It is a current industry practice to design the spools for multiple independent tolerances at extreme limits in all directions. Previous project experience shows that the Algebraic Sum (AS) combination of multiple independent tolerances at extreme limits may result in large spools where the probability of occurrence of these tolerances at extreme limits is quite low.

The use of less conservative SRSS (square root of sum of squares) combination has been suggested in this paper as an alternative to the Algebraic Sum combination. Due to the large number of misalignment components, the probability of exceeding the loads in the spool and at the connector obtained by the SRSS method is small and is within the applicable failure probabilities defined in DNV-OS-F101. The SRSS method is demonstrated in this paper by using a Monte Carlo simulation.

Five different spools have been analysed to demonstrate the suitability of using SRSS misalignments when the spools are designed to DNV-OS-F101. The spools considered include 10″, 16″ and 20″ outside diameter spools to represent different sizes at different loading combinations. Maximum bending moments in the spool and maximum moments at the connector have been considered to check the SRSS feasibility. The results indicate that it is acceptable to use SRSS misalignments as an alternative to AS misalignments. Considering SRSS misalignments in preference to AS leads to reduced spool size and reduced loadings on connectors.
Dynamic Analysis of Aquaculture Fish Cages in Irregular Waves
Authors: Li Li , Fu Shixiao , Li Runpei
Published: November 2013

The aquaculture fish cage encounters random waves in the open sea. Understandings of their dynamic behaviors are important for design of the deepwater fish cages. In this paper, the hydrodynamic responses of a gravity-typed fish cage in irregular waves are studied based on FEM and Morison equations. The floating collar and the bottom ring are modeled by beam elements. Net lines are modeled by truss elements. Hydrodynamic forces are calculated by a modified Morison equation taking the relative motion between the fluid and structure members into account. The displacement responses characters (time history and spectrum) of the fish cage floating collar in random waves are investigated. The response results show some similarities between fish cage in regular waves and irregular waves. Both rigid body motions and flexible structural deformations can be seen of the floating collar and the whole fish cage. The net volume changes with time in irregular wave and also high frequency responses caused by the structural deformation are observed.
Water Injection, Polymer Injection and Polymer Alternating Water Injection for Enhanced Oil Recovery: A Laboratory Study
Authors: Zampieri Marcelo F. , Moreno Rosangela B. Z. L.
Published: November 2013

Developing an efficient methodology for oil recovery is extremely important in this commodity industry, which may indeed lead to wide spread profitability. In the conventional water injection method, oil displacement occurs by mechanical behavior between fluids. Nevertheless, depending on mobility ratio, a huge quantity of injected water is necessary. Polymer injection aims to increase water viscosity and improve the water/oil mobility ratio, thus improving sweep efficiency. The alternating banks of polymer and water injection appear as an option for the suitable fields. By doing so, the bank serves as an economic alternative, as injecting polymer solution is an expensive process.

The main objective of this study is to analyze and comparison of the efficiency of water injection, polymer injection and polymer alternate water injection. For this purpose, tests were carried out offset in core samples of sandstones using paraffin oil, saline solution and polymer and were obtained the recovery factor and water-oil ratio for each method. The obtained results for the continuous polymer injection and alternating polymer and water injection were promising in relation to the conventional water injection, aiming to anticipate the oil production and to improve the water management with the reduction of injected and produced water volumes.
Investigation of the Effects on Benjamin-Feir Instability by Uniform Currents
Authors: Ma Yuxiang , Dong Guohai , Ma Xiaozhou
Published: November 2013

Systematic experiments focusing on the evolution of wave trains with initially sidebands on uniform currents are carried out in a physical wave-current flume (65m long, 2m wide and 1.8m deep). Wave trains with different initial steepness and perturbed sidebands are generated to propagate on currents with velocity in the range −0.1 < U/c < 0.1 (U is the current velocity, c is the phase velocity of the carrier wave in quiescent water). The experimental results demonstrate that following currents can suppress the modulational instability and reduce the onset criterion. However, opposing currents have the contrary effect. In addition, the estimated experimental initial growth rates of the sidebands are close to the result predicted by the current modified cubic nonlinear Schrödinger equation of Gerber. Furthermore, the development of instability of waves on opposing currents tends to occur in a continuous frequency band rather than in some discrete frequencies.
A Method for Modeling of Floating Vertical Axis Wind Turbine
Authors: Wang Kai , Moan Torgeir , Hansen Martin Otto Laver
Published: November 2013

It is of interest to investigate the potential advantages of floating vertical axis wind turbine (FVAWT) due to its economical installation and maintenance. A novel 5MW vertical axis wind turbine concept with a Darrieus rotor mounted on a semi-submersible support structure is proposed in this paper. In order to assess the technical and economic feasibility of this novel concept, a comprehensive simulation tool for modeling of the floating vertical axis wind turbine is needed.

This work presents the development of a coupled method for modeling of the dynamics of a floating vertical axis wind turbine. This integrated dynamic model takes into account the wind inflow, aerodynamics, hydrodynamics, structural dynamics (wind turbine, floating platform and the mooring lines) and a generator control. This approach calculates dynamic equilibrium at each time step and takes account of the interaction between the rotor dynamics, platform motion and mooring dynamics. Verification of this method is made through model-to-model comparisons. Finally, some dynamic response results for the platform motion are presented as an example for application of this method.
Investigation of the 2nd Generation of Intact Stability Criteria for Ships Vulnerable to Parametric Rolling in Following Seas
Authors: Krüger Stefan , Hatecke Hannes , Billerbeck Heike , Bruns Anna , Kluwe Florian
Published: November 2013

The existing IMO intact stability criteria (IS-Code 2008) do not generally provide sufficient safety against dynamic stability failures such as parametric rolling for modern ships. Therefore, new stability criteria have been developed by IMO / SLF. These so-called Second Generation Stability Criteria shall ensure sufficient dynamic stability. The criteria are structured in a three level approach, where the first level consists of quite simple formulae. If a ship does not pass the first level, it is assumed that the ship is vulnerable to the phenomenon addressed, and the second level of criteria shall then be applied. This level consists of computations which are a little more complex, but they still treat the problems addressed in a strongly simplified manner. If now the ship does not pass the second level, a third level shall be applied to ensure that the ship can be designed and operated safely. This third level consists of direct calculation methods which shall be applied, however no criteria or procedures have yet been developed for this third level. We have applied the level 1 and level 2 criteria to a reference ship where a direct stability assessment has been performed during the design. The results showed extremely large scatter in the required GM-values of the criteria, and none of the criteria showed GM values roughly comparable to the direct assessment. The paper shows why the application of the criteria is challenging for the design of RoRo-ships and why a third level (direct assessment) is urgently required before the first two levels are put into force. Some conclusions are also drawn for the possible treatment of the new criteria in a stability booklet.
A Comparison Between Full RANSE and Coupled RANSE-BEM Approaches in Ship Propulsion Performance Prediction
Authors: Queutey Patrick , Deng Gan Bo , Guilmineau Emmanuel , Salvatore Francesco
Published: November 2013

The paper compares the development of the coupling between a viscous Reynolds-averaged Navier-Stokes (RANSE) method and an inviscid Boundary Element method (BEM) with application to the prediction of the propulsive performance of a propelled ship. The BEM computational model is implemented into the PRO-INS code developed by CNR-INSEAN. It is based on a boundary integral formulation for marine propellers in arbitrary onset non-cavitating and cavitating flow conditions. The RANSE approach is based on the unstructured finite-volume flow solver ISIS-CFD. An essential feature for full RANSE simulations with the ISIS-CFD code developed by ECN-CNRS is in the use of a sliding grid technique to simulate the real propeller rotating behind a ship hull. The STREAMLINE tanker and propeller are proposed as validation test case. Full RANSE simulations are performed for design speed only, while hybrid RANSE/BEM self-propulsion computations are performed for a speed range. Both computations are compared with experimental data and show good agreement for ship resistance and for propeller thrust and torque.
Modelling and Analysis of a Semi-Submersible Wind Turbine With a Central Tower With Emphasis on the Brace System
Authors: Luan Chenyu , Gao Zhen , Moan Torgeir
Published: November 2013

This paper deals with analysis of the OC4 DeepCWind semi-submersible wind turbine, which is provided by NREL through the OC4 project. This concept is a three-column semi-submersible supporting a 5 MW wind turbine on an additional central column.

The fact that the semi-submersible floater needs a large water line restoring moment to achieve sufficient stability and the control of the cost based on the steel weight make the design of braces and pontoons very challenging. Effective methods are needed to check the strength of the brace system based on the response forces and moments in the braces under different design environmental conditions, while the floating wind turbine is needed to be considered as an aero-hydro-servo-elastic system.

A novel modeling methodology based on the code Simo/Riflex is introduced in this paper. Simo/Riflex is a state-of-the-art code that can account for the coupling effect between rigid body motions and slender structures (e.g. mooring lines, braces and blades) in the time-domain. Simo/Riflex can be combined with Aerodyn, which is a state-of-the-art aerodynamic code, to model the floating wind turbine as an aero-hydro-servo-elastic system, as well as be combined with simplified aerodynamic codes (e.g.TDHMILL) to improve the efficiency of the numerical simulation.

The novel modeling method can give the forces and moments in the brace system of the floater under hydrodynamic and aerodynamic loads in the time-domain. In order to get the structural response of the braces, the side columns and the central supporting column are modeled as independent rigid bodies in Simo while the braces are modeled by beam elements in Riflex. Master and slave relationship is applied at the joints in between of the columns and braces.

As an application example, the novel modeling method based on the code Simo/Riflex+TDHMILL, which is capable of modeling the floating wind turbine as an aero-hydro-elastic system, has been used to carry out Ultimate Limit State (ULS) design check for the brace system of the OC4 DeepCWind semi-submersible wind turbine based on relevant standards, i.e. NORSOK N00-3, NORSOK N-004, IEC61400-1, IEC61400-3.

The modeling method can also be used by other codes which have similar features as Simo/Riflex.
Point Absorber Design for a Combined Wind and Wave Energy Converter on a Tension-Leg Support Structure
Authors: Bachynski Erin E. , Moan Torgeir
Published: November 2013

A combined wind and wave energy extraction device is studied, consisting of a single column tension leg platform (TLP) which supports a 5MW wind turbine (WT) and 3 point absorber wave energy converters (WECs). Two variations of the WECs are considered: one that is constrained to purely heave motion relative to the TLP hull, and a hinged device which moves in coupled surge and pitch as well as heave. The effects of both types of WECs on the WT power takeoff; on structural loads in the turbine tower and blades, WEC supporting structure, and tendons; and on the platform motions are examined for operational and 50-year extreme environmental conditions.
The Research on Bulk System Transfer Ability of CPOE-16 Jack-Up
Authors: Zeng Ji , Chen Gang , Zhu Kuichen , Mo Jian , Li Chenfeng
Published: November 2013

Bulk transfer systems are part of very important bulk material transferring systems used on drilling rigs, and mainly provide and transfer pulverous material for offshore drilling rigs. The authors use the continuity equation of fluid flow, Bernoulli equation, Theory of energy loss, and gas-solid two phase flow theory to evaluate the bulk transfer ability of the bulk system for the CPOE-16 Jack-up, and to optimize the bulk piping layout, elbow radius and elbow quantity. These research results have been applied to the CPOE-16 Jack-up and have proven that implementation of these results can be effective.
Dynamic Response of Axially Loaded Plates With Intermediate Fixities to Transient Hydrodynamic Impact Loads
Authors: Datta N. , Siddiqui Md. Atif
Published: November 2013

A dynamic analysis of axially loaded plates with intermediate fixities is presented. The underwater part of a craft is modeled as a lightly damped flexible plate, which rises out of the water and slams against it at a large vertical velocity. This causes highly localized hydrodynamic impact pressure moving at high velocities across the plate, setting it into high-frequency vibrations. The natural frequencies of the plate depend on the slenderness ratio, aspect ratio, axial load, and end fixities. The end fixities depend on the quality of welding, and type of bracketing. Normal mode summation method is used to analyze the vibratory response, which is generated for various impact speeds, deadrise angles, end fixities, axial loads, aspect ratios, and slenderness ratios. A parametric study is done to predict the location, instant, and magnitude of the maximum dynamic stresses on the structure. The hydrodynamic pressure is assumed to act on the equilibrium position of the plate, i.e. one-way coupling of the fluid and the structure is studied. The primary aim is to study the time-varying dynamic stress configurations and draw conclusions leading to sound structural designs.
Experimental Study on Flow Around Circular Cylinders With Low Aspect Ratio
Authors: Gonçalves Rodolfo T. , Rosetti Guilherme F. , Franzini Guilherme R. , Fujarra André L. C.
Published: November 2013

Experiments were carried out in a recirculating water channel regarding the flow around stationary circular cylinders with low aspect ratio piercing the water free surface. Eight different aspect ratios were tested, namely L/D = 0.1, 0.2, 0.3, 0.5, 0.75, 1.0, 1.5 and 2.0; this range corresponds to aspect ratio related to circular offshore systems, such as spar and monocolumn platforms. Force was measured using a six degree-of-freedom load cell and Strouhal number is inferred through the transverse force fluctuation frequency. The range of Reynolds number covers 10,000 < Re < 50,000. PIV measurements were performed in some aspect ratio cases, namely 0.3, 0.5, 1.0 and 2.0 for Reynolds number equal to 43,000. The results showed a decrease in drag force coefficients with decreasing aspect ratio, as well as a decrease in Strouhal number with decreasing aspect ratio. The PIV showed the existence of an arch-type vortex originated in the cylinder free end.
Experimental Investigation of VIM Characteristics on Column Type Floater in Super Critical Reynolds Number
Authors: Fujiwara Toshifumi , Saito Masakatsu , Maeda Katsuya , Sato Hiroshi , Ishida Kei
Published: November 2013

In Japan, floating wind turbine facilities are planned to be set in the offshore, where bottom-mounted type’s one is not feasible, to generate natural resource electricity. One of the ways for application is that the facilities are mounted on a column type floater to keep buoyancy and stability in the sea that is called as Spar type. At that time, the characteristic of VIM, i.e. Vortex Induced Motion, on the column type floater is concerned about to maintain mooring safety of the wind turbine.

VIM characteristic on the column type floater was investigated using a huge experimental model in supper critical Reynolds number at the large towing tank in the National Maritime Research Institute, Japan.

The results of the experiment were compared with ones of a small similar figure model under critical Reynolds number, and VIM amplitudes against reduced velocity parameter are clearly understood. The amplitude distribution relating to duration time for large VIM amplitude is also investigated to assess the effect on fatigue damage of mooring lines. These unique and precious results have important role for making the safety guideline on mooring requirement on a column type floater.
Dynamic Response Analysis of a Floating Offshore Wind Turbine During Severe Typhoon Event
Authors: Utsunomiya Tomoaki , Sato Iku , Yoshida Shigeo , Ookubo Hiroshi , Ishida Shigesuke
Published: November 2013

In this paper, dynamic response analysis of a Floating Offshore Wind Turbine (FOWT) with Spar-type floating foundation is presented. The FOWT mounts a 100kW down-wind turbine, and is grid-connected. It was launched at sea on 9th June 2012, and moored on 11th for the purpose of the demonstration experiment. During the experiment, the FOWT was attacked by severe typhoon events twice. Among them, Sanba (international designation: 1216) was the strongest tropical cyclone worldwide in 2012. The central atmospheric pressure was 940 hPa when it was close to the FOWT, and the maximum significant wave height of 9.5m was recorded at the site. In this paper, the dynamic responses of the platform motion, the stresses at the tower sections and the chain tensions during the typhoon event, Sanba (1216), have been analyzed, and compared with the measured data. Through the comparison, validation of the numerical simulation tool (Adams with SparDyn developed by the authors) has been made.
Evaluations of a Ship Evacuation Maneuver From Tsunami Attack
Authors: Kobayashi Ei-ichi , Yurugi Kouhei , Koshimura Shunichi
Published: November 2013

Huge earthquakes have occurred continuously for at least 1000 years along the Nankai Trough, which is located in the Pacific Ocean off Shikoku Island, Japan. There is great concern over the possible occurrence of huge earthquakes, named Toukai, Tonankai, and Nankai earthquakes, along this trough. A tsunami generated by an earthquake in a coastal area not only raises the sea level, but also creates strong horizontal flows in bays. Any ships in the area are subject to these strong lateral flows. Since these phenomena can make a ship’s movement uncontrollable, subject piers to tremendous forces, slam ships into breakwaters, and set vessels adrift and ground them, it is very important to understand them and the resulting movement of a ship, and to consider possible countermeasures. It is particularly urgent to evaluate the effects of a tsunami on ships carrying hazardous materials, such as VLCCs (Very Large Crude Carriers), sailing near the coast or moored to a jetty, and to consider and evaluate ways of countering these effects. From this viewpoint, basic analyses of a VLCC’s movement resulting from a tsunami are carried out, and then countermeasures for avoiding this motion are investigated. First, this paper describes mathematical models of a tsunami flow and the maneuvers of sailing and moored ships. Next, computer simulations of the evacuation maneuvers of a ship at berth to avoid the effects of a tsunami are discussed. Finally, the paper reports additional simulations of the lateral motion of a ship moored at anchor when a tsunami hits.
Estimation of Wave Transmission Through Flushing Culverts in Breakwaters
Authors: Katsardi Vasiliki , Tsoukala Vasiliki K. , Belibassakis Konstantinos A.
Published: November 2013

In the present paper a Coupled-Mode System Model is used for the numerical simulation of wave transmission through flushing culverts. Numerical results are presented for waves propagating over regions with submerged breakwaters, simulating flushing culverts that are never perfectly filled with water. These are compared with a series of 64 experiments, for different wave conditions and/or geometrical characteristics of the openings. The present numerical approach has given good comparisons with more than the 50% of the experimental data. Deviations were observed when simulating steeper waves and/or narrower culverts, enabling the identification of the cases where the increased effects of nonlinearity, the generation of higher harmonics and 3D effects are important and should be taken into account. Nevertheless, the present model can be used as a useful starting tool in calculating efficiently the effectiveness of a flushing culvert in terms of maintaining water quality in a harbor basin.
Scour Assessment and Measurements for Pile-Supported Wind Turbine Foundations
Authors: Stuyts Bruno , Cathie David , Xie Yi
Published: November 2013

With the rapid development of offshore wind energy in Europe, a large number of piled structures are being installed. In areas with sandy seabed conditions, erosion of sediment by the actions of wave and current can negatively influence foundation capacity. An accurate prediction model of scour around the piles is therefore required. Well-accepted scour prediction methods exist; both for the equilibrium scour depth and the time scale of scour [1] around single piles. These standard formulas have been combined with metocean data and a hindcasting model to calculate the expected scour depth around piles of wind turbine tripod foundations. Other causes of scour, such as pile-pile interaction, effect of proximity of structural members to the seabed, and seabed mobility were also assessed in order to determine the amount of global scour to be considered. The scour predictions were compared to measurements taken at an offshore wind turbine foundation at Park Alpha Ventus (PAV) in the German North Sea [2]. The data showed very good agreement with the measured scour around the piles. Both the equilibrium scour depth and time scale of scour were well predicted using the hindcasting model. The measured scour below the central column of the tripod structure exceeded expectations; this is believed to be due to a pumping effect during storm episodes. Finally, the effect of scour on the vertical effective stress around the tripod piles was assessed with a finite element model. Local scour had an important effect while scour below the centre of the structure had a much more limited effect. Considering the combined effects of multiple pile interaction, scour below the central column, and making an allowance for seabed mobility, an equivalent global scour depth for pile capacity calculations was established.
Development of an Economic and Efficient Installation Vessel for Tidal Stream Energy Converter Arrays
Authors: Nicholls-Lee Rachel , Hindley Simon , Parkinson Richard
Published: November 2013

In order for tidal stream technology to develop into a viable and cost effective energy solution, the overall cost of tidal array installation, operations and maintenance must be driven down. The key issues which drive the cost are the time required to conduct operations and susceptibility to weather risk coupled with the expense of marine assets.

Current vessels have limited operational windows due to weather and tidal constraints, which result in considerable cumulative costs due to high charges for such vessels. The marine renewable industry is currently reliant on vessels of opportunity from the offshore oil and gas sector; which, while sufficient for single device demonstration deployments, are not viable for array installations. De-coupling the tidal sector from this market place offers the opportunity to reduce the volatility of vessel day rates.

This paper presents the concept design of an efficient and economic, fit for purpose installation vessel for tidal stream energy converters. The vessel has good dynamic positioning capabilities for operation in strong tidal currents thus broadening the operational window. The environmental impact of the vessel is reduced when compared to existing vessels. A key criterion throughout the design process is minimizing the cost of the vessel to tidal turbine site developers.