bluuebunny/crossref_metadata_2025 huggingface dataset:
The Symbiotic Ideology: Stewardship, Husbandry, and Dominion in Beef Production
Authors: Ellis Colter
Published: November 2013

Social studies of agriculture tend to overlook the micro and symbolic interactions that structure relationships among agriculturalists, the environment, and animals raised as commodities. In this study, I use ethnographic methods and in‐depth interviews with conventional beef producers to understand their perceptions of the environment and the nonhuman animals they raise. Central themes in this setting are the ethics of stewardship and husbandry. I seek to understand how these values are constructed and used interactionally. I argue that stewardship and husbandry help describe a process of co‐constitution that binds together ranchers, cattle, and the natural environment. The analysis engages actor‐network theory by emphasizing nonhuman activeness and draws from symbolic interaction and cultural sociology to show how people interpret the actions of nonhumans. The findings show that ranchers frame their relationships with cattle and the environment as symbiotic and work to understand the interests of the nonhuman as complementary to production. I introduce the termsymbiotic ideologyto show the way this approach mystifies power dynamics embedded in the ethic of dominion.
Tidal signature recorded in burrow fill
Authors: Wetzel Andreas , Carmona Noelia , Ponce Juan
Published: November 2013

The arrangement of sediment couplets preserved in Thalassinoides shafts suggests that tides regulated the passive filling of these trace fossils and, thus, represent tubular tidalites. The thickness variation in individual layers and couplets implies a mixed diurnal, semi‐diurnal tidal signature where packages of either thick‐layered or thin‐layered couplets alternate. Calcarenitic sediment accumulated when tidal current velocity was too high to allow deposition of mud, whereas a marly mud layer is interpreted to have formed during more tranquil times of a tidal cycle (in particular, low‐tide slack water). The tidal record within the burrows covers a few weeks and the corresponding spring–neap cycles. The fill of the Thalassinoides shafts is the only known record to decipher the tidal signature from otherwise totally bioturbated sediments. These deposits accumulated in a lower‐shoreface to upper‐offshore setting during the late Miocene on a shallow shelf extending from the Atlantic Ocean to the west into northern Patagonia. The fill of all investigated burrows started around spring tide and, thus, the behaviour of the burrow producers – probably crustaceans – is speculated to have been affected by tides or the high water level because all studied burrows became abandoned around the same period of a tidal cycle.
Illuminating a Resilient Rural Culture in Twentieth Century Y Fro Gymraeg Using Bourdieu's Bearn
Authors: Baker Sally , Brown Brian J. , Williams Emyr
Published: November 2013

This article uses Bourdieu's analysis of peasant life in the Bearn to illuminate a changing but resilient rural culture in mid‐twentieth century Wales. Rather than finding their culture and language eroded by economic and social change, Welsh speaking participants in this biographical study used the education system to build upon their existing cultural capital previously cultivated through religious and informal civic institutions. A distinctive habitus enabled exchange of locally acquired cultural capital for the symbolic capital of qualifications, in the face of declines in the farming and quarrying industries and consequent loss of employment opportunities. Anglicising influences of upward social mobility were counteracted by Welsh language activism, combined with a sense that Wales was heir to a tradition of Bards and scholars. This helped maintain the illusio that ‘Welsh culture’ was a game worth playing. Unlike peasant life in the Bearn, this story is of transformation rather than demise.
Experimental and numerical analysis of soft tissue stiffness measurement using manual indentation device – significance of indentation geometry and soft tissue thickness
Authors: Iivarinen J. T. , Korhonen R. K. , Jurvelin J. S.
Published: November 2013

Background

Indentation techniques haves been applied to measure stiffness of human soft tissues. Tissue properties and geometry of the indentation instrument control the measured response.

Methods

Mechanical roles of different soft tissues were characterized to understand the performance of the indentation instrument. An optimal instrument design was investigated. Experimental indentations in forearm of human subjects (N = 11) were conducted. Based on peripheral quantitative computed tomography imaging, a finite element (FE) model for indentation was created. The model response was matched with the experimental data.

Results

Optimized values for the elastic modulus of skin and adipose tissue were 130.2 and 2.5 kPa, respectively. The simulated indentation response was 3.9 ± 1.2 (mean ± SD) and 4.9 ± 2.0 times more sensitive to changes in the elastic modulus of the skin than to changes in the elastic modulus of adipose tissue and muscle, respectively. Skin thickness affected sensitivity of the instrument to detect changes in stiffness of the underlying tissues.

Conclusion

Finite element modeling provides a feasible method to quantitatively evaluate the geometrical aspects and the sensitivity of an indentation measurement device. Systematically, the skin predominantly controlled the indentation response regardless of the indenter geometry or variations in the volume of different soft tissues.
Oblique oceanic opening and passive margin irregularity, as inherited in the Zagros fold‐and‐thrust belt
Authors: Navabpour Payman , Barrier Eric , McQuillan Harry
Published: November 2013

The Zagros fold‐and‐thrust belt of SW Iran represents deformation of the former Arabian passive margin since Permian–Triassic opening of the Neo‐Tethys ocean. The Zagros belt is characterized by a present‐day structural salient‐recess setting inherited from past marginal embayment‐promontory geometry, which was involved in discontinuous ophiolite obduction and diachronous continental collision. We examine outcrop‐scale Mesozoic extensional brittle tectonics, preserved as syn‐depositional normal faults within the folded strata, in terms of stress tensor inversion. The result is then integrated with belt‐scale isopach, seismic and topographical data to delineate the geometry of a major irregularity along the passive margin originating from oblique oceanic opening. The implication of this configuration within the tectonic framework of oceanic closure is discussed.
Dam‐to‐offspring transmission and persistence ofStaphylococcus pseudintermediusclones within dog families
Authors: Paul Narayan C. , Damborg Peter , Guardabassi Luca
Published: November 2013

Background

Staphylococcus pseudintermediusis an opportunistic pathogen that causes mainly skin infections in dogs. Although vertical transmission ofS. pseudintermediusstrains from dam to offspring has been reported, the persistence of the dam's strains in offspring over long periods of time is virtually unknown.

Hypothesis/Objectives

The aim of this study was to investigate to what extentS. pseudintermediusclones resident on the dam may be transmitted to and persist in offspring.

Animals

A total of 18 dogs and 50 of their offspring, which had been separated from their mother for between 1 month and 9 years, were enrolled in the study.

Methods

Mouth and perineal swabs taken from all dogs were subjected to selective enrichment and plating on blood agar. PresumptiveS. pseudintermediuscolonies were confirmed by a species‐specificPCRand typed by pulsed‐field gel electrophoresis.

Results

Staphylococcus pseudintermediuswas isolated from both the dam and at least one offspring in 12 of the 18 dog families. Pulsed‐field gel electrophoresis confirmed carriage of indistinguishable or closely related strains in the dam and offspring within four families, despite the fact that they had lived separately for between 2 and 48 months before sampling.

Conclusions and clinical importance

Our results indicate thatS. pseudintermediusclones that are transmitted from the dam to the puppies around birth may persist in the offspring for long periods of time. The study contributes to the current understanding of the mechanisms of spread ofS. pseudintermediusin dogs and highlights the need for research to elucidate the role of bacterial and host genetic factors in colonization.
IMAGING DIAGNOSIS—AN ATYPICAL PRESENTATION OF DIFFUSE IDIOPATHIC SKELETAL HYPEROSTOSIS (DISH) IN A DOG
Authors: Ciepluch Michael F. , da Costa Ronaldo C. , Russell Duncan
Published: November 2013

A 10‐year‐old female spayed Dalmatian was evaluated for progressive cervical scoliosis and stiffness. This imaging report describes the imaging and postmortem findings for this patient. A diagnosis of an atypical manifestation of diffuse idiopathic skeletal hyperostosis (DISH) was made based on imaging and additional diagnostics. This report serves to increase awareness of DISH in the veterinary community, as well as to describe a unique presentation of the disease with atypical lesion distribution and severity. In addition, this report contrasts the pathophysiology and imaging characteristics of DISH with spondylosis deformans, which can appear comparable radiographically.
Phage and MLVA Typing of Salmonella Enteritidis Isolated from Layers and Humans in Belgium from 2000–2010, A Period in which Vaccination of Laying Hens was Introduced
Authors: Dewaele I. , Heyndrickx M. , Rasschaert G. , Bertrand S. , Wildemauwe C. , Wattiau P. , Imberechts H. , Herman L. , Ducatelle R. , Van Weyenberg S. , De Reu K.
Published: November 2013

The aim of the study was to characterize isolates of Salmonella enterica serovar Enteritidis (S. Enteritidis) obtained from humans and layer farms in Belgium collected during 2000–2010. Three periods were compared, namely (i) before implementation of vaccination (2000–2004), (ii) during voluntary vaccination (2005–2006) and (iii) during implementation of the national control program (NCP) for Salmonella including mandatory vaccination against S. Enteritidis (2007–2010). The characteristics compared across time periods were distributions of phage type and multiple‐locus variable number tandem‐repeat assay (MLVA). While PT4 and PT21 were predominantly isolated in Belgium in layers and humans before 2007, a significant reduction of those PTs was observed in both populations in the period 2007–2010. The relative proportion of PT4b, PT21c and PT6c was found to have increased considerably in the layer population since 2007. In the human population, PT8, PT1 and the group of ‘other’ PTs were more frequently isolated compared to the previous periods. When comparing the proportion of the predominant MLVA types Q2 and U2, no significant difference was found between the layer and human population in the three periods and between periods within each category (layer and human). A significant difference in isolate distribution among MLVA clusters I and II was found between human and layer isolates recovered during Period 3 and in the human population between Period 1 and 3. Results suggest that the association between S. Enteritidis in layers and the occurrence of the pathogen in humans changed since implementation of the NCP in 2007.
A Simulink®-Based Building Load-Ground Source Heat Pump Model Used to Assess Short-and Long-Term Heat Pump and Ground Loop Performance
Authors: Gaspredes Jonathan L. , Masada Glenn. Y. , Moon Tess. J.
Published: November 2013

An integrated building load-ground source heat pump model is developed to capture short-term (30 s) and long-term (10–20 yr) performance of ground source heat pumps with vertical boreholes. The model takes advantage of the built-in computation and organization functions of the simulink®/matlab environment to couple the component building load, heat pump, and ground loop models at every time step. The building load model uses the HAMBASE thermal program and is applicable to residential and commercial buildings. The heat pump model uses manufacturer data and sensible heat corrections to accurately model heat pump operation across a wide range of input conditions. The ground loop model is a combination of Hellstrom's borehole tube model, Eskillson's long-term (>10 yr) g-function ground model and the one-dimensional, short-term (<5 min) numerical ground model by Xu. Fifteen year simulation results for a base case residential house are presented to illustrate the integrated model's ability to predict a wide range of time responses and to illustrate a limiting ground loop sizing criterion that reveals the slow degradation in system performance due ground heating effects. Simulations with varying borehole lengths also illustrate the sensitivity of ground loop sizing on the system's thermal and economic performances. The work emphasizes the importance of proper borehole sizing, design, and placement especially in cooling-dominated climates, where the unbalance of heat loads to the ground cause slowly rising ground temperatures.
A Detailed Derivation of the Velocity-Dependent Inertia Forces in the Floating Frame of Reference Formulation
Authors: Sherif Karim , Nachbagauer Karin
Published: November 2013

In the case of complex multibody systems, an efficient and time-saving computation of the equations of motion is essential; in particular, concerning the inertia forces. When using the floating frame of reference formulation for modeling a multibody system, the inertia forces, which include velocity-dependent forces, depend nonlinearly on the system state and, therefore, have to be updated in each time step of the dynamic simulation. Since the emphasis of the present investigation is on the efficient computation of the velocity-dependent inertia forces as along with a fast simulation of multibody systems, a detailed derivation of the latter forces for the case of a general rotational parameterization is given. It has to be emphasized that the present investigations revealed a simpler representation of the velocity-dependent inertia forces compared to results presented in the literature. In contrast to the formulas presented in the literature, the presented formulas do not depend on the type of utilized rotational parameterization or on any associated assumptions.
Study on the Influence of Current Collector on the Sudden Deterioration of Solid Oxide Fuel Cell Anode Performance
Authors: Jiao Zhenjun , Shikazono Naoki
Published: November 2013

The influence of current collector on the sudden deterioration phenomena of conventional nickel-yttria-stabilized zirconia composite solid oxide fuel cell (SOFC) anodes operated in hydrogen with high humidity concentration is investigated. Current collectors of different materials have been tested within different conditions. It is found that the loss of contact between current collector mesh and the top surface of an anode cause the sudden deterioration of the anode. Platinum and gold current collector meshes have been proven to lead to the sudden deterioration of an anode in short time operation in high humidity conditions in conventional SOFC operation temperatures.
Design and Balance-of-Plant of a Demonstration Plant With a Solid Oxide Fuel Cell Fed by Biogas From Waste-Water and Exhaust Carbon Recycling for Algae Growth
Authors: Gandiglio Marta , Lanzini Andrea , Santarelli Massimo , Leone Pierluigi
Published: November 2013

The design and balance-of-plant of a novel anaerobic digestion (AD) biogas solid oxide fuel cell (SOFC) plant is assessed. Biogas from waste-water treatment plant is the fuel feeding the SOFC system. Simultaneous multigeneration of electricity, heat and a fuel (algae, in our case) via exhaust carbon recycling is accomplished in the proposed plant configuration. CO2 capture from the SOFC anode exhaust is carried out through an oxy-combustion reactor that completes the oxidation of spent fuel still available downstream of the fuel cell. The captured CO2, after water condensation, is thus fed to an array of photo-bioreactors where C biofixation in algae is achieved. The design of the main plant sections, including the gas cleaning unit, fuel processor, SOFC “hot-box,” oxy-combustor, CO2/H2O condensation unit and photo-bioreactors, is provided. A system analysis of a full-scale version of the biogas SOFC power plant with optimized heat integration is finally analyzed to fully understand the potential of the proposed integrated energy system. An overall electrical efficiency exceeding 52% (LHV basis) was calculated. Sensitivity analyses have been carried out in order to study the influence of fuel utilization, internal reforming, biogas composition and steam-to-carbon ratio on both SOFC and overall plant performance.
Ablation Dynamics of Silicon by Femtosecond Laser and the Role of Early Plasma
Authors: Zhao Xin , Shin Yung C.
Published: November 2013

In this paper, the femtosecond laser ablation of silicon is investigated by a two-dimensional hydrodynamic model. The ablation depth of the silicon wafer ablated in air at different laser intensities is calculated, and the corresponding experimental measurements are carried out for validation. Two different ablation regimes have been identified by varying the laser fluence. While two-photon absorption dominates in the low fluence regime (< 2 J/cm2), electron heat diffusion is a major energy transport mechanism at higher laser fluences (> 2 J/cm2). The ablation efficiency first increases with the laser fluence, and reaches the peak value at the laser fluence around 8 J/cm2. It starts to drop when the laser fluence further increases, because of the early plasma absorption of the laser beam energy.
An Approach for Increasing Branch Height of a Hydroforming T-Joint With Smaller Branch Diameter
Authors: Peng Junyang , Liu Gang , Teng Bugang , Wang Xiaosong , Feng Sule
Published: November 2013

Hydroforming of a stainless steel T-joint with ratio of tube diameter to thickness D/t = 108 and ratio of branch diameter to tube diameter d/D = 0.6 was studied. The effects of counter punch loading path on branch height and thickness were discussed. Because the branch diameter is smaller than the tube diameter, it is difficult to obtain a higher branch height and avoid thinning at the same time. An approach for increasing branch height of a hydroforming T-joint with smaller branch diameter was proposed. Finite element method (FEM) simulations were carried out for analyzing the deformation during hydroforming of the T-joint. Thinning ratio distribution, stress and strain states from different loading paths were presented. The experimental results show that the new approach with counter punch moving backwards during calibration is effective to increase branch height and to improve thickness distribution.
An Experimental Study on Edge Chipping in Ultrasonic Vibration Assisted Grinding of Bio-Ceramic Materials
Authors: Tesfay Hayelom D. , Xie Yuzhu , Xu Zhigang , Yan Bing , Li Z. C.
Published: November 2013

Bio-ceramics have been widely employed in dental restorations, repairing bones, and joint replacements etc. due to their high compressive strength, superior wear resistance, and natural aesthetical appearance. Abrasive machining processes such as grinding have been used to obtain a smooth surface and desired dimensions for bio-ceramic parts. However, a major technical issue resulted from abrasive machining processes is edge chipping. The edge chipping could lead to the failure of bio-ceramics and has to be removed by downstream processes. It not only increases machining cost but also introduces potential deficiencies into the bio-ceramic parts. This paper present an experimental study on the edge chipping in ultrasonic vibration assisted grinding (UVAG) of bio-ceramic materials. An innovative UVAG system is developed and employed to machine three bio-ceramic materials (Lava, partially fired Lava, and Alumina). The effect of ultrasonic vibration on the edge chipping is investigated by observing under scanning electron microscope (SEM). The experimental results show that the edge chipping can be significantly reduced with the assistance of ultrasonic vibration. For the diamond grinding, there exist a lot of edge chippings along the machined slot edge that varies from 0.3 mm to 1.2 mm, whereas for the UVAG, there are only several tiny edge chippings with size from ∼0.03 mm to ∼0.1 mm along the machine slot edge. The results indicate that the UVAG system developed has a great potential to be used in production to improve bio-ceramic materials’ surface integrity, in particular, edge chipping quality.
Multi-Constraint Optimization for Grinding Nickel-Based Alloys
Authors: Pavel Radu , Wang Xiqun , Srivastava Anil K.
Published: November 2013

Nickel-based alloys (Ni-based alloys) are used on a large scale in military, aerospace, missile and defense applications with the aim of improving performance, life, and fuel efficiency. Grinding is extensively used for final finishing of these components. Due to their specific material properties, such as work-hardening and low thermal conductivity, the workpieces made of Ni-based alloys are difficult to grind. The difficulty consists in finding the combination of dressing and grinding parameters that generate the prescribed dimensions, finish, and surface integrity of the finished part with high productivity. Increasing productivity is generally associated with increasing the material removal rate. This, in turn, can create detrimental effects on the ground parts such as micro-cracks, high residual stresses, white layers, and thermal damage. This paper presents a novel methodology for determining an optimal combination of dressing and grinding parameters with respect to maximizing the material removal rate, while taking into account a number of process constraints including: grinding force, power, surface roughness, wheel wear, and surface integrity. According to this methodology, predictive models for grinding behavior are determined using a reduced number of experiments based on an in-process, fast sensor data acquisition system. The models are used as inputs for the multiple criterion optimization program based on a genetic algorithm approach. A CNC surface grinding machine was instrumented to allow process monitoring and data collection. The model building and the optimization methodology have been validated using specimens made of Ni-based alloys. The workpiece materials and the range of the grinding parameters were selected according to applications from aerospace industry. The results support the use of adopted methodology for finding the optimal combination of dressing and grinding parameters.
Burr Formation and Surface Quality in High Speed Micromilling of Titanium Alloy (Ti6Al4V)
Authors: Bajpai Vivek , Kushwaha Ajay K. , Singh Ramesh K.
Published: November 2013

Titanium and Ti alloys are popular materials used in aviation and biomedical field due to their excellent strength-to-weight ratio and corrosion resistance properties. Micromilling is a common mechanical machining process used in the production of microscale features. The micro-tool has very low stiffness and even small forces can lead to catastrophic tool failure. High speed micromachining can be used to address the issue because of lower chip loads at higher rotational speeds. Consequently, high speed micromilling can be used for micromachining of hard metals/alloys which are difficult to accomplish at lower speeds. Nowadays high speed micromilling is gaining popularity due to its high material removal rate and good surface finish. In many cases, the machined product does not need an additional finishing process. However, the burr formation in the mechanical machining process is the most important problem which becomes more critical for a microscale feature. Removal of micro-size burr is much more difficult than its macro counterpart. The current work is focused on the characterization of the burr formation in high speed micromilling. Influence of various process parameters, viz., spindle speed, feed rate, depth of cut, tool diameter and number of flutes of the micromilling tool has been analyzed on the burr size and on the quality of the machined surface via measuring the surface roughness.
Ultrasound Induced Synthesis of CdS Nanocrystals Under Continuous Flow
Authors: Palanisamy Barath , Paul Brian
Published: November 2013

Cadmium sulfide nanoparticles generally exhibit quantum confinement effects when the particle size is less than 10 nm and approaches the Bohr exciton radius. It is a widely used buffer material in solar cells owing to its wide band transmission of solar light and hence used as a window layer in photovoltaic devices. Sonochemical synthesis permits the rapid heating of reactant baths by acoustic cavitation leading to high local temperatures. In this research, results from batch trials for heating and synthesis are reported. These results were used to design experiments for the continuous synthesis of CdS nanoparticles using a sonochemical reactor consisting of a flow cell and a high intensity horn. By utilizing the continuous synthesis approach a more than hundred fold reduction in processing time over batch synthesis for similar product was reported.
Probabilistic Modeling of Extreme Value Distributions of Ice Loads on “Molikpaq” Platform for Sakhalin-II Project
Authors: Bekker Alexander T. , Sabodash Olga A. , Kovalenko Roman G.
Published: November 2013

Characteristics of the drifting ice cover and the scenarios of the ice loads on offshore structures are the major parameters defining durability and reliability of the ice-resistant platforms on the Sakhalin offshore.

The study is devoted to the problems of probabilistic and numerical modeling of the process of interaction between the ice cover and the ice-resistant concrete structures on the Sakhalin offshore zone. Geometry of the “Molikpaq” (PA-A) platform for Sakhalin-II Project is used as an example. The input statistical data were received on the basis of full-scale observations of the ice conditions in the Piltun-Astokhskoe deposit area during 1989–2002.

The distribution of probability exceedance of ice loads for various ice scenarios on the “Molikpaq” (PA-A) platform was received. A probabilistic estimation of extreme values of ice loads was carried out, taking into account return period of ice conditions.
Laterally Loaded Piles With Wings: In Situ Testing With Cyclic Loading From Varying Directions
Authors: Rudolph Christina , Grabe Jürgen
Published: November 2013

The application of piles as foundations for offshore wind turbines yields new requirements for the design. Wind and waves induce a cyclic lateral loading on the pile which changes direction corresponding to the meteorological conditions. Cyclic lateral loading on piles results in accumulated displacements, depending on the cyclic load level and load characteristics. The deformation can increase significantly due to a varying loading direction. Under such loading conditions the pile can drift sideways even if the loading is symmetric. Wings attached to the pile shortly below the seabed have been known to reduce deformations on laterally loaded piles as they locally enlarge the diameter on which the soil resistance is activated. They also change the cross-section of the pile from a circular shape to a star-shape. This might reduce the drifting of the pile. A series of large-scale in-situ tests has been carried out in order to identify the effects of changing loading direction as well as the applicability of winged piles to reduce deformations. Two tubular steel piles (one of them equipped with wings) have been installed and subjected to high-cyclic lateral loading from varying directions. In this paper the in-situ tests and their results are presented.
Friction, Contact Pressure and Non-Linear Behavior of Steel Tubes in Subsea Umbilicals
Authors: Parsinejad Farzan , Kassner Chris , Kurtz Mark , Ye Naiquan
Published: November 2013

Steel tube umbilical risers in deep water applications are subject to significant variable environmental loads during operation. These tubes are designed to carry high pressure fluids, up to 15,000 psi. The stresses accumulated in the walls consist of contribution from movement of the floating platform on which the umbilical is connected, axial tension due to the weight of umbilical and ancillaries, and internal pressure due to end cap effect.

The helically wound steel tubes in umbilicals are un-bonded and can slip against adjacent layers. Therefore the stresses in these tubes experience a hysterical feature when the slip changes directions. It is known that in addition to bending stress, friction stress range has a major contribution in fatigue damage. If there is full slip, the friction stress range will be a constant value regardless of the load variation. However in many cycles the full slip is not reached and the stress range is proportional to load variation.

This paper focuses on evaluating the impact of friction and contact pressure on helical steel tubes. The initial gaps between steel tubes and adjacent layers, friction coefficients and the contact stiffness are the main factors that affect such investigation. A novel methodology by using UFLEX2D (a MARINTEK product) has been applied for modeling complex umbilical cross sections and for the study of these parameters.

Two cross sections for the same subsea application but with different designs have been investigated in the study. It has been shown how fatigue damage can be significantly impacted by different cross sectional design.

For this study, non-linear moment/curvature relationship has been included in the analyses. Based on the findings of this study, more realistic results can be achieved by including the non-linear behavior in global analysis for fatigue damage calculations instead of using nominal bending stiffness supplied by umbilical manufacturer.
Failure of Rubble Mound Beneath Caisson due to Earthquake-Induced Tsunami
Authors: Zen Kouki , Kasama Kiyonobu , Kasugai Yasuo , Dong Simeng
Published: November 2013

The 2011 off the Pacific Coast of Tohoku Earthquake on the 11th of March, 2011 had induced a gigantic Tsunami and caused the catastrophic damage in the northeast coast area of Japan. Lots of breakwaters have been seriously damaged in this disaster, including the world deepest breakwaters, Kamaishi Harbor Mouth Breakwaters. According to a wave height recorder, a large hydraulic head difference between the seaside and harbor side of breakwaters was observed for long duration of several minutes or more. Such a hydraulic head difference as observed generates the seepage flow in the rubble mound underneath the caisson. The seepage flow is considered one of the influential factors causing the instability of caisson type composite breakwaters.

In order to find out the instability mechanism of caisson type composite breakwaters against tsunami, 1) the pop-out phenomena of armored blocks on the mound, 2) the possibility of shear failure of rubble mound and 3) the reduction of bearing capacity of rubble mound due to seepage flow are investigated. Both theoretical analysis and laboratory experiment are represented in this paper.

The safety factors for the pop-out failure and shear failure of rubble mound were theoretically derived. A scale of 1/100 model experiment was performed in laboratory. Loading tests were carried out to investigate the reduction of bearing capacity under the existence of seepage flow. From the results of laboratory experiment and theoretical analysis, it was confirmed that the pop-out phenomenon happens and the bearing capacity of rubble mound can considerably decrease due to the tsunami-induced seepage flow. It is concluded that the effect of seepage flow in the rubble mound should be taken into account when making a design of the caisson type composite breakwater against tsunami.
Real-Time Finite Element Analysis of a Remotely Operated Pipeline Repair System
Authors: Steinke Dean M. , Nicoll Ryan S. , Roy André R.
Published: November 2013

Remotely operated vehicle (ROV) pilots are frequently trained to operate in increasingly complex subsea environments using ROV simulators. These computer simulators de-risk important subsea operations by increasing ROV pilots’ skill levels in performing tasks under challenging environmental and operational constraints. ROV pilot-training simulation scenarios typically involve a variety of subsea equipment, such as trees, flow lines, pipeline end terminations (PLETs), etc. However, many critical ROV tasks, such as pipeline repair or riser installation, involve flexible structures. The following paper investigates a method for accurately simulating pipelines and flexibles within an ROV pilot-training simulator. The goal of the technology development is to enable engineers and marine operators to assess the risks associated with certain tasks, such as pipeline repair or flexible hook-up, in real-time using ROV simulation technology. In particular, the challenge that this paper will address is how to determine the stresses in a subsea pipeline using a lumped mass finite-element cable model within a multi-body simulation framework.

Repair of subsea pipelines is a complex multi-step process typically carried out by ROVs. During pipeline repair, a pipeline repair system (PRS) is lowered to the seabed. The PRS must lift the pipeline off the seabed and the damaged section of pipeline must then be cut and removed, and a new section of pipeline put in place. During the lifting, cutting and installation phases it is important that the pipeline is not overstressed and the equipment used in the repair operation is not overloaded. In addition, there are a wide array of operational variables, procedures and decisions that must be evaluated. Towards this end, an ROV simulation facility capable of assessing stresses and operations in real-time was constructed using the finite element simulation software package ProteusDS in conjunction with GRI Simulations Inc.’s VROV simulator. The system was designed to evaluate the impact of different combinations of operating parameters and is intended to be useful for system design and analysis. The system would be of immense utility in rapid response to a real-world incident where the system may be called into action. The following paper reviews the simulation framework, the models employed, the results of model verification, and discusses the challenges of the project.
A Nonlinear Numerical Wave Tank and its Applications
Authors: Sun Hui , Faltinsen Odd M.
Published: November 2013

A two-dimensional fully nonlinear numerical wave tank is developed by using a boundary element method (BEM). The water depth can be shallow or deep. The waves are generated by simulating a piston wave maker or by specifying the input velocity at the upstream boundary. Fully nonlinear free surface conditions are satisfied in the numerical simulations. In the downstream region, a numerical beach is employed to dissipate the wave energy to avoid waves reflecting from the vertical downstream boundary. When there is a body piercing the free surface, another numerical beach is applied upstream the body to damp out only the reflected waves from the body. Two different applications are presented in this paper. The first one is to compute the pressure and velocity at any point inside the wave field. The other application is to calculate the forces on a horizontal cylinder fixed on the free surface. This second application is related to the investigation of the hydrodynamic forces on the pontoon of a fish farm. Nonlinearities are significant since the wave amplitudes can be large relative to the wavelength and the dimension of the cylinder.
Wet Welding Field Trials in Shallow Waters for Structural Repairs in Floating Oil Production Units
Authors: Pessoa Ezequiel C. P. , Bracarense Alexandre Q. , Santos Valter R. , Assunção Fernando C. R. , Monteiro Maurício J. , Marinho Ricardo R. , Vieira Leonardo A. , Siva Dario Barbalho
Published: November 2013

Saving costs is a major attraction of wet welding application in structural repairs of offshore installations. Nevertheless, improve the quality of wet welding to get it as close as possible to plain structural steel quality and also qualify welding procedures in AWS D3.6 class ‘A’ have been challenges not consistently overcome. This paper describes wet welding trials in shallow waters (5m and 10m) with a rutile and an oxy-rutile type, both commercial electrodes. Two different base metal compositions were employed in the preparation of butt and fillet joints. The main objective is to amend new results of wet weds properties to those already published aiming the application of this welding technique under more reliable conditions and the qualification of welding procedures. The weldments were tested by Vickers hardness, Charpy V notch, tensile, shear strength, bending and fillet weld break tests, chemical and macrographic analysis. Some of these properties and diffusible hydrogen, obtained in laboratory with a mechanized gravity system, will also be presented in order to complement or explain the field testes results obtained. Both electrodes produced class AWS E 70XX weld metals and overall results according class “B” requirements of the AWS D3.6M:2010 code. Some good elongation results obtained encourage future trials to achieve class “A”. Barriers to the class “A” qualification of welding procedures in shallow waters are also discussed.
Two Phase Flow Simulation With Lattice Boltzmann Method: Application to Wave Breaking
Authors: Banari Amir , Grilli Stephan T. , Janssen Christian F.
Published: November 2013

A new Lattice Boltzmann method (LBM) is developed to efficiently simulate multiphase flows with high density ratios, in order to study complex air-sea interaction problems, such as wind wave breaking and related sea-spray generation. In this method, which builds and improves on the method proposed earlier by [1], the motion of (diffusive) interfaces between fluids is modeled by solving the convective Cahn-Hilliard equation with the LBM. As in the latter work, we eliminate instabilities resulting from high density ratios by solving an additional Poisson equation for the fluid pressure. The resulting numerical scheme is computationally demanding since this equation must be solved over the entire computational domain, which motivates implementing the method on the massively parallel environment offered by General Purpose Graphical Processing Units (GPGPU), via the nVIDIA CUDA framework. In this paper, we present the equations and numerical methods for the method and the initial validation of the resulting multiphase-LBM for standard benchmark problems such as Poiseuille flow, a rising bubble, and Rayleigh-Taylor instability for two-fluid systems. A good agreement with the reference solutions is achieved in all cases. Finally, the method is applied to simulating an ocean breaking wave in a space periodic domain. In all the presented applications, it is observed that the GPGPU implementation leads to speed-ups of about two orders of magnitude in comparison to a single-core CPU implementation. Although the method is only currently implemented in a two-dimensional (2D) framework, its extension to three-dimensions (3D) should be straightforward, but the need for the efficient GPGPU implementation will become even more drastic in 3D.
Lateral Buckling Behaviour of Snake-Lay Pipeline With Vertical Support at Crown
Authors: Raveendra Reddy N.
Published: November 2013

Most hydrocarbon pipelines installed recently in the Middle East operate at relatively high pressures and temperatures: maximum inlet operating temperatures >90°C and pressures >135 barg. These pipelines are susceptible to Euler buckling from high axial compressive force induced in the pipeline by the temperature and pressure. Any uncontrolled lateral buckling is a potential hazard for a pipeline’s structural integrity, especially when all compressive force is released at one point and excessive feed-in occurs.

Possible mitigation measures include lateral restraint by rock dumping or trenching, or midline spools. Another possibility is to induce the pipeline to buckle in a controlled manner, perhaps at several locations, rather than allowing it to suffer an uncontrolled, large buckle at one location only. This is known as buckle initiation. “Snake-lay” and “Vertical Imperfection” are two methods that have been implemented successfully to initiate controlled buckling. “Buoyancy” is another method, but is yet to be implemented.

Snake-lay is a relatively reliable solution but, depending on pipe-soil interaction, sometimes requires a very short radius to initiate the buckle. Installing large diameter pipelines with short radii may invite other problems such as pipeline instability during laying, or may require additional counteracting measures to maintain the specified lay radius. The lay radius can be increased with additional sleepers at the crown of the snake-lay, with a well-defined low friction factor between the pipeline and the support.

This paper discusses the behavior of snake-lay pipeline with and without vertical sleeper supports at the crown of the pipeline, and demonstrates what effects supporting the pipeline at the crown will have on the buckling mechanism and the pipeline integrity.
The Performance of Dynamically Embedded Anchors in Calcareous Silt
Authors: Gaudin Christophe , O’Loughlin Conleth D. , Hossain Muhammad S. , Zimmerman Evan H.
Published: November 2013

The Omni-Max anchor is a new type of dynamically installed anchor featuring a mooring arm located close to the anchor tip that is free to rotate about the anchor length. An experimental programme has been undertaken on a geotechnical centrifuge to assess the anchor performance in calcareous silt. The testing programme includes (i) anchor drops and measurement of the penetration depth, and (ii) anchor pull and assessment of the anchor trajectory. An anchor embedment model based on strain rate enhanced shearing resistance is capable of satisfactorily predicting anchor embedment using model parameters that are similar to those used for clay. The diving behaviour of the anchor, post keying, is demonstrated, provided that the initial embedment after impact is deep enough to prevent a shallow mechanism to develop during anchor keying.
Optimal Shear Key Interval for Offshore Shallow Foundations
Authors: Feng Xiaowei , Gourvenec Susan
Published: November 2013

Embedment of offshore shallow foundations is typically achieved by ‘skirts’, i.e. thin vertical plates that protrude from the underside of a foundation top plate and penetrate the seabed confining a soil plug. Skirted shallow foundations are often idealized as a solid, rigid element for geotechnical analysis of the foundation, on the assumption that sufficient skirts, or ‘shear keys’ will be provided to ensure that the deformable soil plug displaces as a rigid body. Should too few shear keys be provided, failure mechanisms involving deformation within the soil plug may occur, leading to a reduction in load-carrying capacity.

There is currently no formal guidance regarding the optimal spacing of shear keys to ensure rigid body displacement of the soil plug. The absence of guidance may lead to unconservative designs if the number of shear keys is under estimated to save on fabrication or to conservative designs if additional shear keys are provided to minimize the risk associated with the uncertainty. Either case is undesirable and clear benefit is to be gained from a better understanding of shear key spacing.

This paper presents guidance on the minimum number of shear keys required to achieve optimal capacity of square and rectangular skirted foundations (i.e. equivalent to that of a solid rigid foundation) under undrained generalized six degree-of-freedom loading in soft soils with linearly increasing shear strength with depth.
Design and Testing of Scale Model Wind Turbines for Use in Wind/Wave Basin Model Tests of Floating Offshore Wind Turbines
Authors: Fowler Matthew J. , Kimball Richard W. , Thomas Dale A. , Goupee Andrew J.
Published: November 2013

Model basin testing is a standard practice in the design process for offshore floating structures and has recently been applied to floating offshore wind turbines. 1/50th scale model tests performed by the DeepCwind Consortium at Maritime Research Institute Netherlands (MARIN) in 2011 on various platform types were able to capture the global dynamic behavior of commercial scale model floating wind turbine systems; however, due to the severe mismatch in Reynolds number between full scale and model scale, the strictly Froude-scaled, geometrically similar wind turbine underperformed greatly. This required significant modification of test wind speeds to match key wind turbine aerodynamic loads, such as thrust. To execute more representative floating wind turbine model tests, it is desirable to have a model wind turbine that more closely matches the performance of the full scale design.

This work compares the wind tunnel performance, under Reynolds numbers corresponding to model test Froude-scale conditions, of an alternative wind turbine designed to emulate the performance of the National Renewable Energy Laboratory (NREL) 5 MW turbine. Along with the test data, the design methodology for creating this wind turbine is presented including the blade element momentum theory design of the performance-matched turbine using the open-source tools WT_Perf and XFoil. In addition, a strictly Froude-scale NREL 5 MW wind turbine design is also tested to provide a basis of comparison for the improved designs. While the improved, performance-matched turbine was designed to more closely match the NREL 5 MW design in performance under low model test Reynolds numbers, it did not maintain geometric similitude in the blade chord and thickness orientations. Other key Froude scaling parameters, such as blade lengths and rotor operational speed, were maintained for the improved designs. The results of this work support the development of protocols for properly designing scale model wind turbines that emulate the full scale design for Froude-scale wind/wave basin tests of floating offshore wind turbines.
Collapse and Buckle Propagation of Sandwich Pipes: A Review
Authors: An Chen , Duan Menglan , Estefen Segen F.
Published: November 2013

Sandwich pipes (SP) can be an effective solution for ultra-deepwater submarine pipelines, combining high structural resistance with thermal insulation. Most research work on this subject has been conducted at the subsea technology laboratory (LTS) of COPPE/UFRJ, with the aim of developing qualified pipes to transport deepwater oil and gas, especially for the pre-salt reservoirs at Offshore Brazil. This article reviewed most of the research done in recent years (2002–2012) on the buckling, collapse and buckle propagation of SP, which emphasized on the development of theoretical, experimental and numerical methods adopted to analyze such structural behavior of SP with different core materials. The main mechanical and thermal properties of the previously considered core materials were also given, together with the elastoplastic constitutive model for each material. The experimental and numerical results of collapse and buckle propagation under external pressure for SP were summarized. A general discussion of the mechanical failure modes of SP under external pressure was also provided. Besides, some suggestions for future work on collapse behavior and buckle propagation of SP were given.