bluuebunny/crossref_metadata_2025 huggingface dataset:
Pollination and sterility in horseradish
Authors: Walters S. Alan , Bernhardt Peter , Joseph Michael , Miller Allison J.
Published: October 2016

Horseradish (Armoracia rusticana, Brassicaceae) is a crop that seldom produces viable seed and is propagated exclusively via vegetative (or clonal) procedures for commercial production. Male sterility and self‐incompatibility (SI) have been suspected as possible mechanisms underlying sterility in horseradish. Therefore, greenhouse and laboratory analyses were conducted to assess pollen viability, pollen recognition in pistils, and to quantify success in self‐ and cross‐pollination events using various horseradish clones. Pollen viability was high (98–100%); consequently, male sterility was an unlikely explanation for low seed set. Self‐pollination in some horseradish clones produced seed, although most clones showed some level of SI. Significant numbers of pollen tubes were found in ovaries of self‐compatible (SC) individuals soon after stigmas were saturated with pollen; furthermore, between three and six ovules with pollen tubes were found in the micropyle which correlates with the number of seed typically found in mature fruits from outcrossed or SC individuals. The results of this study suggest variation in the breeding system of horseradish, as some clones exhibit complete SC, while other clones are SI that recognize and reject self‐pollen.
Identification of novel alleles from wild barley for the improvement of alpha‐amylase and related malt quality traits
Authors: Cu Suong T. , March Timothy J. , Degner Sophia , Eglinton Jason K.
Published: October 2016

Germplasms consisting of 64 wild barley accessions (Hordeum vulgare ssp. spontaneum) were examined for polymorphisms in α‐amylase using both isoelectric focusing (IEF) and thermostability assays. Wide variation was found for the high pI α‐amylase with 20 IEF band patterns identified. Enzyme activity and thermostability assays showed large differences among α‐amylase isoenzymes. Two wild accessions Tel‐Shoket CPI 77146‐32 and Afiq CPI 77128‐41 showed superior enzyme activity and thermostability compared with commercial varieties such as ‘Baudin’, ‘Flagship’ or ‘Navigator’. The functionality of the Tel‐Shoket allele was validated in backcross lines with ‘Flagship’ as the recurrent parent. The Tel‐Shoket allele at the amy1 locus increased α‐amylase thermostability at 75°C by 8.4% and α‐amylase activity in kilned malt by 18.7%. The introgression of the wild allele also led to significant improvements in fermentability, hot water extract and viscosity. Gene sequencing showed that there are three single nucleotide polymorphisms in the Tel‐Shoket amy1 sequence, which can be used as diagnostic markers for the selection of this allele in breeding programmes.
The Photostabilizing Effect of Grape Seed Extract on Three Common Sunscreen Absorbers
Authors: Martincigh Bice S. , Ollengo Moses A.
Published: October 2016

The photostabilizing ability of grape seed extract on three common sunscreen absorbers, 2‐ethylhexyl‐p‐methoxycinnamate (EHMC), benzophenone‐3 (BP3) and tert‐butylmethoxy dibenzoylmethane (BMDBM), was investigated. Samples were exposed to simulated solar radiation and monitored by spectrophotometric and chromatographic methods. The chemical composition of the grape seed extract was determined by GC‐MS and HPLC‐MS, and the major secondary metabolites were found to be epicatechin and catechin. Exposure of the extract to UV radiation increased the UV absorption capacity of the extract. All sunscreens showed an improved photostability in the extract. The inherent photo‐instability of BMDBM when exposed to UV radiation was almost eliminated in the presence of grape seed extract. A mixture of all three sunscreens in the extract showed very high photostability and a red shift covering the entire UVB and UVA regions, thereby improving the broad‐spectrum protection. The incorporation of grape seed extract in sunscreen and other cosmetic formulations for topical application boosts photoprotection by stabilizing the UV filters and enhancing broad‐spectrum coverage. This in turn helps in reducing the amounts of absorbers and other additives incorporated in a sunscreen product and consequently lowers the risk of an unprecedented buildup of photoproducts whose toxicities are currently unknown.
Evaluation of follicular growth and tissue viability in vitrified/warmed domestic dog ovaries after in vitro culture
Authors: Ackermann CL , Asa CS , Krisher R , Bauman K , Casey S , Lopes MD
Published: October 2016

Contents

Cryopreservation of gametes is an important tool to preserve fertility, but for most species, including domestic dogs, data regarding ovarian tissue cryopreservation are limited. We aimed to evaluate the follicular and tissue viability and follicular growth after in vitro culture of domestic dog ovarian cortical slices cryopreserved by vitrification. Ovarian cortex was obtained from ten pairs of ovaries from domestic dogs using two methods (A and B), one for each ovary from the same bitch. At least four slices for each method were obtained from each ovary, one was processed for histology and the other three were vitrified. When the vitrified slices were warmed, one slice from each method was processed for histology and the remaining two slices were cultured in vitro for 7 days, after which they were processed for histological evaluation. Density of follicles in fresh samples was similar for both methods. For Method A, density of secondary follicles decreased, while the density of primordial follicles was maintained throughout the process. For Method B, density of primary follicles decreased after 7 days of incubation, but density of secondary follicles increased, confirming follicular growth in Method B. Overall, there were no differences between Methods A and B in follicular integrity after incubation. Fresh samples showed better arterial, venous and follicle preservation, followed by vitrified–warmed samples, but no differences were observed between methods. In conclusion, the methodology used to isolate the ovarian cortex may affect tissue and follicle viability as well as follicular development during in vitro culture.
Additive Manufacturing Integrated Energy—Enabling Innovative Solutions for Buildings of the Future
Authors: Biswas Kaushik , Rose James , Eikevik Leif , Guerguis Maged , Enquist Philip , Lee Brian , Love Lonnie , Green Johney , Jackson Roderick
Published: October 2016

The additive manufacturing integrated energy (AMIE) demonstration utilized three-dimensional (3D) printing as an enabling technology in the pursuit of construction methods that use less material, create less waste, and require less energy to build and operate. Developed by Oak Ridge National Laboratory (ORNL) in collaboration with the Governor's Chair for Energy and Urbanism, a research partnership of the University of Tennessee (UT) and ORNL led by Skidmore, Owings & Merrill LLP (SOM), AMIE embodies a suite of innovations demonstrating a transformative future for designing, constructing, and operating buildings. Subsequent, independent UT College of Architecture and Design studios taught in collaboration with SOM professionals also explored forms and shapes based on biological systems that naturally integrate structure and enclosure. AMIE, a compact microdwelling developed by ORNL research scientists and SOM designers, incorporates next-generation modified atmosphere insulation (MAI), self-shading windows, and the ability to produce, store, and share solar power with a paired hybrid vehicle. It establishes for the first time, a platform for investigating solutions integrating the energy systems in buildings, vehicles, and the power grid. The project was built with broad-based support from local industry and national material suppliers. Designed and constructed in a span of only 9 months, AMIE 1.0 serves as an example of the rapid innovation that can be accomplished when research, design, academic, and industrial partners work in collaboration toward the common goal of a more sustainable and resilient built environment.
Multiscale Strain as a Predictor of Impact-Induced Fissuring in Articular Cartilage
Authors: Henak Corinne R. , Bartell Lena R. , Cohen Itai , Bonassar Lawrence J.
Published: October 2016

Mechanical damage is central to both initiation and progression of osteoarthritis (OA). However, specific causal links between mechanics and cartilage damage are incompletely understood, which results in an inability to predict failure. The lack of understanding is primarily due to the difficulty in simultaneously resolving the high rates and small length scales relevant to the problem and in correlating such measurements to the resulting fissures. This study leveraged microscopy and high-speed imaging to resolve mechanics on the previously unexamined time and length scales of interest in cartilage damage, and used those mechanics to develop predictive models. The specific objectives of this study were to: first, quantify bulk and local mechanics during impact-induced fissuring; second, develop predictive models of fissuring based on bulk mechanics and local strain; and third, evaluate the accuracy of these models in predicting fissures. To achieve these three objectives, bovine tibial cartilage was impacted using a custom spring-loaded device mounted on an inverted microscope. The occurrence of fissures was modulated by varying impact energy. For the first objective, during impact, deformation was captured at 10,000 frames per second and bulk and local mechanics were analyzed. For the second objective, data from samples impacted with a 1.2 mm diameter rod were fit to logistic regression functions, creating models of fissure probability based on bulk and local mechanics. Finally, for the third objective, data from samples impacted with a 0.8 mm diameter rod were used to test the accuracy of model predictions. This study provides a direct comparison between bulk and local mechanical thresholds for the prediction of fissures in cartilage samples, and demonstrates that local mechanics provide more accurate predictions of local failure than bulk mechanics provide. Bulk mechanics were accurate predictors of fissure for the entire sample cohort, but poor predictors of fissure for individual samples. Local strain fields were highly heterogeneous and significant differences were determined between fissured and intact samples, indicating the presence of damage thresholds. In particular, first principal strain rate and maximum shear strain were the best predictors of local failure, as determined by concordance statistics. These data provide an important step in establishing causal links between local mechanics and cartilage damage; ultimately, data such as these can be used to link macro- and micro-scale mechanics and thereby predict mechanically mediated disease on a subject-specific basis.
A Three-Dimensional Diffusion Filtering Model Establishment and Analysis for Point Cloud Intensity Noise
Authors: Zhang Yi , Lyu Xiuqin
Published: October 2016

To improve the quality of point cloud data, as well as maintain edge and detail information in the course of filtering intensity data, a three-dimensional (3D) diffusion filtering equation based on the general principle of diffusion filtering is established in this paper. Moreover, we derive theoretical formulas for the scale parameter and maximum iteration number and achieve self-adaptive denoising, fine control of the point cloud filtering, and accurate prediction of the diffusion convergence. Through experiments with three types of typical point cloud intensity data, the theoretical formulas for the scale parameter and iteration number are verified. Comparative experiments with point cloud data of different types show that the 3D diffusion filtering method has significant denoising and edge-preserving abilities. Compared with the traditional median filtering algorithm, the signal-to-noise ratio (SNR) of the point cloud after filtering is increased by an average of 10% and above, with a maximum value of 40% and above.
Verification of Length Scale Effects on Solution Accuracy of Hybrid RANS-LES Methods
Authors: Kumar Gaurav , Gopalan Harish , Chandar Dominic , Nguyen Vinh-Tan , De Ashoke
Published: October 2016

Hybrid RANS-LES methods are gaining popularity for the simulation of the complex bluff body flows at high Reynolds numbers due to their reduced computational cost and good accuracy. A number of such methods have been proposed in the literature. Each of these methods have enjoyed varying degree of success for different applications. One of the most important parameter which determines the switching between near-wall RANS region and off-body LES region is the length scale parameter. This parameter can be grid based or physics based and numerous choices exist for defining this parameter. This study proposes to investigate the effect of this parameter on the size of the RANS and LES regions and also on the solution accuracy. Four test problems are chosen covering attached, mildly separated and massively separated flow regimes. Results will help us to identify length scale definitions to be used for different flow scenarios.
Experimental Study of Compositional Factor on Asphaltene Deposition for Heavy Crude Oil Dilution in Offshore Production and Transportation
Authors: Jing Jiaqiang , Wu Cheng , Chen Xiaoshuang , Chen Junwen , Lu Ping , Hu Anlin
Published: October 2016

Heavy oil dilution has been widely used in the oil production and transportation due to its high efficiency in viscosity and drag reduction, and great convenience in operation. The composition of the heavy oil will change while being mixed with some diluents, thus the stability of the asphaltene in the heavy oil might be destroyed, which leads to a tremendous threat to the safe and economic operation of the production and transportation system. The asphaltene contents of eight onshore and offshore oil samples were measured using n-heptane and toluene, then the asphaltene deposition onset points of the oils diluted with n-alkanes (n-C7) were evaluated using viscosity methods. The reliability of the asphaltene deposition predicted by the refractive index of the diluted oils was verified, and meanwhile the impacts of n-C5, n-C7 and n-C8 on the asphaltene precipitation behavior were measured and analyzed. And then the status of the asphaltene deposition, suspending particle distribution and adhesion of the heavy oil diluted with diesel in the stainless wire mesh located in the visible loop pipe layout was investigated. The studied results demonstrate that the asphaltene deposition onset point has no direct relation to its content, and those of the eight diluted oils ranged from 15% to 30% at 70 °C. The onset point prediction method was verified to be reliable because it is based on that the critical solubility parameter and the square root of the diluent molar volume in the Asphaltene-Instability-Trend (ASIST) curve present a good linear relation. The relationship between the refractive index of the diluted oil and its asphaltene deposition onset point depends on the light oil type, and the smaller its carbon number, the more serious the asphaltene deposition in its diluted oil. The reasonable amount of a light oil blended with a heavy oil should well consider the light oil source, its economy and the asphaltene deposition risk at the same time.
The Transient Temperature Prediction in the Deepwater Riserless Well
Authors: Feng Ming , Teodoriu Catalin , Schubert Jerome
Published: October 2016

The offshore wells are subject to hostile environments of such areas as the North Sea, GOM and the high arctic. The strong loop ocean currents and induced eddies can pose significant problems for deep-water well.

Broadly divided ocean currents, surface currents, bottom currents and vertical currents, interact with the deep water well structures as one of environmental forces.

One of the engineering challenges in deep water drilling is temperature gradient. In the past the temperature in the wellbore was ignored and an isothermal system was assumed because no practical means existed to determine the well bore temperature profile. But the fact is that the negative thermal gradient exists between surface to seafloor and it becomes positive below the seafloor. The extreme values could be as low as 40°F and as high as 150∼200°F.

In addition to low temperature condition, the significant heat exchange also occurs for high temperature and geothermal reservoirs. The universal matrix form of implicit finite differential equations is introduced to predict the temperature profile of the fluid in the well and near-wellbore formation. This paper is to combine various factors together to derive a solver for the transient temperature modeling during the dirculation of riserless drilling, which can be the basis to describe the near-wellbore well stability under geo-thermal stress and predict the annular pressure during HPHT injection or production, which can also be used to including but not limited to the dynamic temperature profile and bottom-hole temperature, improving cementing program design, casing thermal stresses to be determined.
Investigation of Well Production Mechanism in Heavy Oil Reservoirs Underlain by Strong Bottom Water
Authors: Qin Wenting , Wojtanowicz Andrew K. , Luo Pingya
Published: October 2016

Low recovery factor is identified as the main problem encountered in the heavy oil production from a strong bottom-water-drive reservoir. Unlike for conventional oils, where the expected recovery from such reservoirs could be very high — in excess of 50 percent, the expected recovery factor in heavy oil water-driven reservoirs is less than 20 percent. In this study, a qualitative analysis of the well productivity mechanisms specific for heavy oil reservoirs with bottom water is provided. The objective is to understand what make the production of heavy oil different to that of lighter oils, identify the mechanism that mostly hamper the well’s productivity and recovery efficiency.

Many believe the by-passed oil due to water coning is the major cause of low ultimate oil recovery in heavy oils underlain by strong bottom water. However, in this paper, we identify another important parameter affecting recovery efficiency in such reservoirs, which hasn’t been recognized by others and its effect on recovery process is significant. The mathematic modeling and numerical study lead to a new finding: due to the aquifer’s influence on pressure response in reservoir, a no-flow boundary at xi is established, where xi is often much smaller than that of the actual reservoir size xe. The oil out to the distance xi is immobile and become bypassed oil, which accounts for large amount of the OOIP. Even the water coning can be effective controlled; the ultimate oil recovery factor will not be improved significantly if the small mobilized oil zone can’t be enlarged. An analytical solution is derived in this paper to calculate the actual drainage radius. The validity of this analytical solution is confirmed by numerical simulation runs.
Analysis of Wave Energy Sources in the North Atlantic Waters in View of Design Challenges
Authors: Taboada Jose V. , Lemu Hirpa G.
Published: October 2016

This paper describes a wave energy analysis of North Atlantic waters and provides an overview of the available resources. The analysis was conducted using a scatter diagram data combined with wave statistics and empirical parameters given by wave height and periods. Such an overview is instrumental for modelling of wave energy sources, design of wave energy converter (WEC) devices and determination of locations of the devices. Previous survey of wave energy resources widely focused on determination of the reliability on installations of WECs. Though the renewable energy source that can be utilized from the waves is huge, the innovative work in design and development of WECs is insignificant and the available technologies still require further optimization. Furthermore, the wave potential of North Atlantic waters is not sufficiently studied and documented. Closer review of the literature also shows that wave energy conversion technology, compared with other conversion machines of renewable energy sources such as wind energy and solar energy, seems still immature and most of the research and development efforts in this direction are limited in scope. The design of energy converters is also highly dictated by the wave energy resource intensity distribution, which varies from North to South hemisphere. The immaturity of the technology can be attributed to several factors. Since there are a number of uncertainties on the accuracy of wave data, the design, location and installation of WECs face a number of challenges in terms of their service life, structural performance and topological configuration. As a result, collection and assessment of wave characteristics and the wave state conditions data serve as key inputs for development of robust, reliable, operable and affordable wave energy converters. The fact that a number of variables are involved in wave distribution characteristics and the extraction of wave power, treating these variables in the design process imposes immense challenges for the design optimization and hence the optimum energy conversion. The conversion machines are expected to extract as high wave energy as possible while their structural performance is ensured. The study reported in this paper is to analyse wave data over several years of return periods with a detailed validation for wave statistics and wave power. The analysis is intended to contribute in better understanding of the wave characteristics with influencing parameters that can serve as design optimization parameters. A method is proposed to conduct a survey and analysis of the available wave energy resources and the potential at cited locations. The paper concludes that wave energy data accuracy is the baseline for project scoping, coastal and offshore design, and environmental impact assessments.
Direction Drilling Measurement Errors Caused by Drilling Fluid Constituents
Authors: Pattarini Giorgio , Rawlins Sheldon , Saasen Arild , Amundsen Per Amund , Poedjono Benny
Published: October 2016

Materials in drilling muds are known to sometimes distort the geomagnetic field at the location of the Measurement While Drilling (MWD) tool magnetometers that are used to measure the azimuth of well path. This distortion or shielding effect can contribute to substantial errors in determination of azimuth while drilling deviated wells and with significant well displacements, these errors may result in missing the target of a long deviated section in the range of 1–200m; and thus impact on the overall productivity expectation of the well.

The article describes significant shielding effects observed while drilling long wells. The criteria for acceptance of the surveys were not met and resultantly, an alternative survey source had to be obtained with resulted in increased cost and time to the client. A number of measures were implemented to eliminate this shielding effect.

The effects of drilling fluid contamination by magnetic materials are calculated, and a method to evaluate the magnetic properties of the drilling fluid is proposed. The effect of taking measurements with the pumps on versus off is quantified.
Predicted Ice Accretion on Horizontal Surfaces of Marine Vessels and Offshore Structures in Arctic Regions
Authors: Dehghani-Sanij Alireza , Muzychka Yuri S. , Naterer Greg F.
Published: October 2016

Sea spray icing is one of the most significant problems for the operation of marine vessels and offshore structures in Arctic regions. This phenomenon affects the stability of marine vessels and offshore structures, and also the safety of human activities onboard. In this paper, a new predictive icing model for large horizontal surfaces of a marine vessel is developed. To obtain the total flux of sea spray during the icing process, both wind spray and wave spray are considered. By applying heat, mass and salt concentration balances, the freezing fraction, temperature distribution, ice layer and water film thicknesses are determined. Moreover, the effects of different parameters on the freezing fractions at various air temperatures are investigated. The results indicate that air temperature, wind velocity, vessel speed, spray water salinity, height from the water surface, and angle between the vessel heading and wind/wave direction are major parameters in the growth rate of the ice. This theoretical method provides a reasonably accurate and simple way for predicting the sea spray icing phenomena on marine vessels and offshore structures.
Assessment Procedures for Mechanical Securing Components of LNG Cargo Containment System With Potential Damages
Authors: Cho Sung-In , Hwang Jung-Oh , Bang Chang-Seon , Bae Jun-Hong
Published: October 2016

This research has been performed to evaluate the structural integrity of the LNG cargo containment system. The structural integrity under vibrational loading and hull deflection was evaluated for damaged and undamaged systems. The test Mock-ups had been constructed for vibrational loading tests and hull deflection tests to compare the system behaviors under the damaged and the undamaged conditions. The damaged Mock-up was constructed with particular damages at the mechanical joints of the top and the bottom boards. The damages of the joints were applied at the designated points, which were selected based on the FEM analysis that compares the stress levels for the various damaged systems.

The static tests were performed when the bottom board and the top board was installed, respectively. The visual inspection had been performed to compare the structural integrity of the damaged and the undamaged system during and after the tests. The vibrational loading tests had also been performed to compare the fatigue performance of both the damaged and the undamaged system. Endurance tests were performed for both vertical and lateral directions based on the results of resonance search tests. The specimens were vibrated at the resonant frequencies determined to most seriously affect the structural integrity. Abnormality of the acceleration time history had been monitored during the endurance tests and the acceleration level at the beginning of the test was compared with the level at the end of the test. After the endurance tests, the structural integrity of both systems had been thoroughly investigated by visual inspection.
Research on the Uncertainty Analysis in CFD Simulation of the Dredging Dustpan
Authors: Lu Yu , Hu Ankang , Chang Xin
Published: October 2016

The main focus of this paper is on the uncertainty analysis methodology and procedure in CFD recommended by 22nd ITTC and the benchmark database for the verification and validation of the results of dredging dustpan’s inlet and outlet cross-section velocity ratio coefficient viur. Compared with the previous uncertainty analysis of CFD focused on the fluid grid-convergence in the steady flow, which is less to consider other factors that may affect the accuracy of the results of numerical simulation, this study compensates for this deficiency and implements the grid-convergence and time-step-size-convergence studies respectively by using three types of grids and time step sizes with refinement ratio under the condition of unsteady flow. Through confirming the validity of CFD uncertainty analysis, the agreement between the numerical simulation correction values from the grid-convergence and time-step-size-convergence and the benchmark test data is found to be quite satisfactory. The results obtained in this study have shown that it is indispensable to carry out the time-step-size-convergence studies for CFD uncertainty analysis during the unsteady flow calculation because the numerical simulation errors respectively caused by the grid and time-step-size in the convergence study have the same order of magnitude. In further the present study of simultaneously conducting both grid-convergence and time-step-size-convergence is demonstrated efficient and effective in the CFD uncertainty analysis.
Subsea Wellhead Fatigue Analysis With Focus on Thermal Conditions
Authors: Cantinelli Sevillano Lucas , De Andrade Jesus , Stanko Milan , Sangesland Sigbjørn
Published: October 2016

The structural integrity of subsea wellhead systems has to be maintained during the life cycle of a well and is of concern when frequent intervention and workover operations are performed to extend its service lifetime. Recent efforts have been made to improve and standardize methods for modeling wellhead fatigue-related loads and expected service life. Nevertheless, no comprehensive study of thermal loads and their implications on wellhead fatigue calculation has been published so far. This paper addresses the significance of thermal-related loads on wellhead fatigue damage assessment during the drilling phase of a subsea satellite well.

Subsea wells are exposed to dynamic loads during drilling operations that are transmitted to the wellhead through the marine riser, which may reduce their functionality over time. The wellhead housing is located on top of a shoulder in the conductor housing. As a result, forces on the wellhead datum are transferred between the wellhead housing, casing strings, the template and soil. The way in which forces are exerted on the different wellhead structural components is strongly dependent on factors such as wellhead design, soil support, cement level and bonding between conductor and surface casing.

To investigate the effects of thermal loading, numerical analyses have been performed based on the finite element method. First, the temperature profiles along the wellbore were estimated during the drilling operation, given the circulation of drilling fluids. Temperature data at selected moments were input to a 3-D structural local analysis of the wellhead. Then, its response to imposed mechanical and thermal loads was investigated. A beam proxy model of the wellhead was established and coupled to the global riser analysis, including the marine riser subject to environmental loading and the corresponding top-end vessel motion, which gave the load history on the wellhead according to the environmental loading. Local and global analysis results combined yielded the fatigue damage incurred in the wellhead during the drilling operation.

Four different top of cement configurations for the surface casing were considered in the study. It was found that the induced thermal variation on the wellhead may lead to significant variation in the numerical estimation of fatigue damage rates during a drilling operation. The results indicate that the impact of thermal loading is strongly dependent on the cement level.
Study on Distribution Law and Stationarity of Global Ice Loads Registered in Experiments in Ice Tank
Authors: Dobrodeev Aleksei , Zvyagin Petr , Sazonov Kirill
Published: October 2016

Being confident in ice loads time series distribution law is extremely important for analysis, as well as for performing simulations. Strong autocorrelation, which usually exist in registered data, obstructs making outcomes on process distribution. Furthermore, at the moment there are only cautious suggestions exist about connection of ice loads distribution law with size and shape of structure or its fragment.

In the paper new results about distribution law of ice loads time series, which were registered in experiments with indenters and models of offshore structures in Krylov State Research Center ice tank (St. Petersburg), are presented. Experiments with four thin indenters were taken in consideration. Also results of tests on process’ variance and means constancy for mentioned time series are presented. Such analysis was performed using methods and software, developed in St. Petersburg State Polytechnic University and Krylov State Research Center.

As a result, hypotheses on ice loads stationarity are tested. Results are discussed.
Experimental Determination of the Ultimate Strength of Box Girder Specimens
Authors: Lindemann Thomas , Kaeding Patrick , Backhaus Eldor
Published: October 2016

The Finite Element Method (FEM) is a feasible tool to perform progressive collapse analyses of large structural systems. Despite enormous developments in finite element formulations and computer technologies the results of structural analyses should be validated against experimental results. In this paper the collapse behaviour of two identical box girder specimens is determined experimentally for the load case of pure longitudinal bending. The specimens are composed of stiffened plate panels and connected at either ends to a loading structure. Within a 4-point bending test a constant bending moment is applied to each specimen to determine the collapse behaviour even in the post-ultimate strength range. The results of the experimental determination of the ultimate strength are presented for the box girder specimens. To simulate the collapse behaviour a finite element model is used and validated against experimental results.
Numerical Analysis of Gas Leakage Problem Based on Improved Gas Storage Vessel Leakage Model
Authors: Sun Liping , Wan Zhiqiang , Ai Shangmao , Li Jiaji
Published: October 2016

The gas leakage accidents always lead to great damages in the process of off-shore oil and gas treatment, consisting of health, wealth and environment losses. When leakage happens, the leakage duration, leak amount and other corresponding parameters are very important on the topic of emergency reaction and decision. The leaking process is complex and cumbersome, so the solving of the leakage problem could be quite difficult. On this point view, a specific and direct solution is given to the leakage problem on the basis of the leakage theory in this paper. According to the improved gas storage vessel leakage model, the mathematical differential method and discretization method are conducted to calculate the result of gaseous container leakage of any kind, consisting of leakage duration, leak amount, residual amount of gas and the residual pressure in the container. There are two probable flowing state of gas during the leakage. So, there is a requirement for different solving methods and principles for gas leakage in different flowing states. There is also calculation for residual amount of gas and residual gas pressure in the container at any given time point. The MATLAB program language is conducted to design the specific computing program and finish the GUI achievement of the program according to the fixed calculative methods and parameters concerned. Carry out the calculation of a fictive leakage problem with the designed MATLAB program, and get the result. It shows that the computing program comes to good leakage result, and the program can also result in acceptable outcome at any chosen time point on the issue of calculating residual amount and residual pressure of gas in the container. The computing program can solve the leakage problem veritably to some degree.
Risk Evaluation of Explosion in FPSO Based on Failure Model and Effect Analysis
Authors: Sun Liping , Niu Zhiyou , Ma Gang , Li Yang
Published: October 2016

As large offshore drilling facility, Floating Production Storage and Offloading (FPSO) faces with the risk of oil & gas leakage and subsequent effects (e.g. fire and explosion). In order to assess FPSO gas leakage and subsequent chain effects risk scientifically, a FPSO topsides is analyzed, and Failure Model and Effect Analysis (FMEA) method is applied to find out which equipment has high Risk Priority Number (RPN). The results show that gas washing pry of FPSO in operation phase has high RPN and needs significant attention. In this paper, CFD-model of FPSO topsides is established based on computational fluid dynamics (CFD) theory. The leak rate of gas with specified hole diameter is calculated based on appropriate leak source model according to the actual operating conditions of gas washing pry. Then based on the simulation results diffusion behavior is analyzed, as well as distribution law of gas and the hazardous area of gas of gas washing pry under the leakage conditions. Furthermore, one explosion model is selected, and then damaging over-pressure of explosion on each equipment surface and the variation trend and influence scope of explosion over-pressure are derived to evaluate personnel and equipment risk. Targeted technical measures will be put forward to reduce risk.
Wave Response of Closed Flexible Bags
Authors: Lader Pål , Fredriksson David W. , Volent Zsolt , DeCew Jud , Rosten Trond , Strand Ida M.
Published: October 2016

Recent environmental considerations, as salmon lice, escape of farmed fish and release of nutrients, have prompted the aquaculture industry to consider the use of closed fish production systems. The use of such systems is considered as one potential way of expanding the salmon production in Norway.

To better understand the response in waves of such bags, experiments were conducted with a series of 1:30 scaled models of closed flexible bags. The bags and floater were moored in a wave tank and subjected to series of regular waves (wave period between 0.5 and 1.5s and wave steepness 1/15, 1/30 and 1/60). Three different geometries were investigated; cylindrical, spherical and elliptical, and the models was both tested deflated (70% filling level) and inflated (100% filling level). Incident waves were measured together with the horizontal and vertical motion of the floater in two points (front and aft). Visual observations of the response were also done using cameras.

The main finding from the experiments were that a deflated bag was more wave compliant than an inflated bag, and that the integrity (whether water entered or left the bag over the floater) was challenged for the inflated bags even for smaller waves (identified as wave condition B (1.0m<H<1.9m) in Norwegian Standard NS 9415). A deflated bag is significantly more seaworthy than an inflated bag when it comes to integrity and motion of the floater.
Pressure Load on Rigid Structure Induced by Double Underwater Explosions
Authors: Han Rui , Zhang Aman , Wang Shiping
Published: October 2016

Underwater explosion is a severe threat to nearby ocean structures, such as underwater construction, floating vessels. The pressure load produced by underwater explosion of explosives consists of shock wave load and the explosion bubble pulsation pressure load. After the detonation, there will be a shock wave propagating radially outwards and it’s followed by a large oscillating bubble. The shock wave has the first damaging effect on adjacent structures. Then, the collapse and high-speed jet of oscillating bubbles will cause the second damage to structures. When there are double explosive sources near a rigid structure, the mutual superposition of shock waves and the interaction between two bubbles may improve the explosive damage. If the distance between one explosive source and the rigid structure is fixed, the damage force produced by double underwater explosions is related to many factors, like the detonation time difference and the distance between two explosive sources. At first, the pressure field in single explosive source case is numerically simulated by using the AUTODYN in this paper. Next, pressure fields of underwater explosion detonated by double sources at the same time and with time difference are calculated, respectively. The flow fields in double explosive sources case are compared with that in single explosive source case. The effect of the detonation time difference and the distance between explosive sources on the damage force is investigated and analysed in detail.
Transient Response of Coated Submersible Hull to Deep Underwater Explosion
Authors: Yin Caiyu , Jin Zeyu , Chen Yong , Hua Hongxing
Published: October 2016

Underwater explosion (UNDEX) can severely damage warships and submarines, so improving shock resistance ability of such weapons is of great importance. However, studies on enhancing shock resistance ability of submerged structures are limited. In this paper, the shock mitigation effects of cellular cladding coated on the submersible hull subjected to combined loads of hydrostatic pressure and shock wave are analyzed. First, one-dimensional analytical model is proposed to reveal the shock mitigation mechanism of cellular claddings. The pressure at fluid-structure interface and the thickness of cellular foam needed to fully dissipate shock energy are obtained. Then, the finite element method is employed to investigate the transient response of bare/coated submersible hull subjected to UNDEX. The results indicate that the cellular cladding coated on the pressure hull is very effective on reducing hull deformation, velocity and acceleration response if the cladding is not fully densified. Otherwise, the stress enhancement appears when the cladding is fully densified prematurely, which will weaken the shock mitigation effects. The research results are useful in designing surface shields for submersible hull so as to enhance its resistance to underwater shock damage.
A Data Mining Approach to Identify Maneuvers in Ship In-Service Measurements
Authors: Abbasi Hoseini Afshin , Steen Sverre
Published: October 2016

An increasing number of ships are equipped with vessel monitoring systems logging ship data during normal operation. We developed a framework for multivariate time series data mining to extract the information of vessel behavior from an in-service dataset. The approach is established on unsupervised data clustering using Self-Organizing Map (SOM), K-means, and k-Nearest Neighbors Search (K-NNS) for searching specific maneuvers. The results are based on ship monitoring data of NTNU’s research vessel, Gunnerus. It is shown that this approach is effective to detect prior unknown ship states with acceptable accuracy. The framework proposed and the results of this work can be of interest to those involved in ship administration, marine traffic flow engineering, ship maneuvering studies and assessment of ship design.
Inherent Strain Method for Residual Stress Measurement and Welding Distortion Prediction
Authors: Ma Ninshu , Nakacho Keiji , Ohta Takahiko , Ogawa Naoki , Maekawa Akira , Huang Hui , Murakawa Hidekazu
Published: October 2016

Inherent strain method was employed to measure the distribution of three dimensional welding residual stresses in several multi-pass welded joints of thick pipes and thick cladded plates. Since a function expression approach to the distribution of inherent strains was developed, the measuring efficiency for three dimensional internal welding residual stresses in complicated welded joints was improved a lot. The residual stresses measured by inherent strain method were compared with the high cost stress release method and neutron diffraction method. Furthermore, inherent deformation parameters, which are defined by integrated values of inherent strains on transverse sections, were used for the fast prediction of welding distortion in assembling structures. Based the predicted welding distortion, its mitigation methods such as tack welding and jig constraint were discussed.
Verification of Class B S-N Curve for Fatigue Design of Forged Steel Connectors
Authors: Zhang Y.-H. , Maddox S. J. , Manteghi S.
Published: October 2016

The fatigue design of forged steel connectors in steel catenary risers (SCRs) is commonly based on the BS 7608 Class B S-N curve, which was derived from longitudinal butt weld data. However, there is very little direct support for this. Therefore, its validity was checked by performing a fatigue test programme involving strip specimens extracted from actual forged J-lay connectors. The effects of stress ratio and surface roughness on fatigue strength were investigated. On the basis of these test results, together with available published data obtained from specimens or structural components that failed in plain steel, the Class B S-N curve was verified. The method was particularly conservative for low stress ratios in the high-cycle regime and a procedure based on the use of the Goodman diagram was devised for correcting the Class B curve for mean stress. Surface roughness in the range investigated, between 3.2 and 8.1μm in Ra, had little effect on the fatigue performance of the forged steel.
The Effect of Different Methods of Simulating Water Particle Kinematics on the 100-Year Responses
Authors: Mohd Zaki N. I. , Abu Husain M. K. , Abdullah Shuhaimy N. , Najafian G.
Published: October 2016

Linear random wave theory (LRWT) is frequently used to simulate water particle kinematics at different nodes of an offshore structure from a reference surface elevation record. However, it is well known that LRWT leads to water particle kinematics with exaggerated high-frequency components in the vicinity of mean water level (MWL). A number of empirical techniques have been suggested to provide a more realistic representation of near surface wave kinematics. The empirical techniques popular in the offshore industry include Wheeler stretching, linear extrapolation, delta stretching, and vertical stretching. Each of these methods is intended to calculate sensible kinematics above the MWL, yet they have been found to differ from one another in the results yielded. In this paper, two new methods of simulating water particle kinematics are introduced. In this study, the values of 100-year responses derived from different methods of simulating wave kinematics are compared.
Towards Numerical Simulation and Model Test Verifications for an Analytical Model of Tubular Member Under Lateral Impact Scenario
Authors: Hu Zhiqiang , Jiang Chao , Liu Kun
Published: October 2016

Tubular member of jacket platform has the possibility of being struck by the service ship under a lateral impact scenario. An analytical theoretical method has been proposed to predict the structural deformation and the resistance force. This paper addresses a study on the verifications for this analytical method, through numerical simulation and model test methods. The analytical method was proposed based on a new structural sectional deformation mode, which considers both of the local denting and global bending deformation. The analytical method is briefly introduced. The verification work includes three steps. Firstly, a model test was conducted, on purpose of obtaining the structural deformation and the resistance force under the lateral impact scenario when a model tubular member was struck by a wedge hammer. In the test, the tubular member was fixed at both ends and the wedge hammer hit at its middle position. A high speed camera was used to record the instantaneous motion track of the hammer, and with the motion track data, the striking force and the indentation can be obtained. Then, a curve of impact force vs. indentation in time series was got. Secondly, the numerical simulations were conducted to simulate the corresponding impact scenario. The code LS_DYNA was used. The curve of impact force vs. indentation was also obtained. Finally, a comparison study was made, to verify the accuracy of the analytical theoretical model, and it is proved that the curves match well. Furthermore, four more cases were conducted by numerical simulations, to assess the feasibility of the analytical method on prototype scantling using for the tubular member of jacket platform.