bluuebunny/crossref_metadata_2025 huggingface dataset:
Design, Analysis and Verification of Moored Floating Caisson System
Authors: Chakrabarti Partha , Chakrabarti Subrata K. , Mukkamala Adinarayana , Anavekar Nagaraj , Qiang Shen , Krishna M. Sri
Published: January 2009

Tacoma Narrows Constructors (TNC) is building a new suspension bridge in Tacoma, close to Seattle, Washington State, USA. The new bridge will be built just south of the existing bridge mounted on two caissons, referred to as East Caisson (Tacoma side) and West Caisson (Gig Harbor side). Each pier is about 80’ wide and 130’ long in plan. The mooring system for each caisson consists of two sets of mooring lines: lower and upper. Each set consists of 16 mooring lines. The lower 16 lines consist of anchors that form a radius of about 300 feet. The fairlead locations for these lower 16 lines are kept constant throughout the construction process. These 16 lines are hooked-up after the caisson is towed from the harbor and positioned at the site. For the upper 16 lines (except three lines on East Pier), the anchor locations form a radius of 600’. The fairlead locations for these upper 16 lines vary based on the draft. Due to the proximity of the proposed caissons to the existing piers and the varying bottom topography, considerable turbulence and vortex shedding is expected which will cause current induced dynamic forces on the caissons. This paper describes the design and analysis of this multi-line mooring system for Tacoma Narrows Bridge caissons, based on the construction sequence in the floating condition. The analysis involved optimizing the anchor locations and the line pretensions, determining the dynamic motions of the caissons, maximum line loads, and corresponding safety factors. The paper includes the hydrodynamic analysis for added mass, and damping, the methodology used for the nonlinear moored caisson analysis (MOTSIM), and the validation of the design tool with other similar models (e.g., StruCAD*3D). The results of the analysis and design are discussed.
Predicting the Maximum Mooring Force of a Moored Floating Offshore Structure
Authors: Mazaheri Said , Incecik Atilla
Published: January 2009

The prediction of extreme mooring forces of moored floating offshore platforms due to long-term met-ocean database can be carried out using a response-based method. As the extreme mooring force for a symmetric turret-moored FPSO is related to the extreme platform excursion, the response-based method can be applied to obtain the extreme platform excursion in the first place and then the extreme mooring force can be determined from the predicted excursion. One can also predict the extreme mooring force by applying the response-based method. This can be done by generating the database of mooring force relevant to the database of met-ocean parameters. In this paper these two approaches of the response-based method are applied to a turret-moored FPSO and the results are compared with each other.
Fracture Mechanics Analysis of Fatigue Crack Repaired Joints
Authors: Rodri´guez-Sa´nchez J. Efrai´n , Dover William D. , Brennan Feargal P. , Rodri´guez-Castellanos Alejandro
Published: January 2009

Fatigue life predictions based on fracture mechanics calculations are required to satisfy an increasing level of safety demanded by industry. These predictions are mainly used to schedule NDT inspections and with inspection data make structural integrity assessments. The periodic inspection-assessment process can lead to the implementation of a fatigue crack repair by crack removal. Fracture mechanics analysis is used again to determine whether or not a repair will be effective. For the case of tubular joints, in offshore structures, once repairs have been shown to be ineffective it is usually required to install a clamp to maintain the continuity of joint members if the structure is still required for production. In this paper a fracture mechanics analysis of crack repaired joints based on Y factors is presented. The analysis is used to predict fatigue life after crack removal and is validated against T-butts experimental data. The analysis is also extrapolated for the prediction of fatigue life of crack repaired tubular joints.
A Second Order Lagrangian Model for Irregular Ocean Waves
Authors: Fouques Se´bastien , Krogstad Harald E. , Myrhaug Dag
Published: January 2009

Synthetic Aperture Radar (SAR) imaging of ocean waves involves both the geometry and the kinematics of the sea surface. However, the traditional linear wave theory fails to describe steep waves, which are likely to bring about specular reflection of the radar beam, and it may overestimate the surface fluid velocity that causes the so-called velocity bunching effect. Recently, the interest for a Lagrangian description of ocean gravity waves has increased. Such an approach considers the motion of individual labeled fluid particles and the free surface elevation is derived from the surface particles positions. The first order regular solution to the Lagrangian equations of motion for an inviscid and incompressible fluid is the so-called Gerstner wave. It shows realistic features such as sharper crests and broader troughs as the wave steepness increases. This paper proposes a second order irregular solution to these equations. The general features of the first and second order waves are described, and some statistical properties of various surface parameters such as the orbital velocity, the slope and the mean curvature are studied.
Comparative Study on the Wave Impact Load in a Sloshing Tank
Authors: Kyoung J. H. , Kim J. W. , Bai K. J.
Published: January 2009

Wave impact load occurring in a liquid storage tank during a sloshing motion is numerically simulated. Due to a violent sloshing, an excessive impact load can cause a critical damage to the tank structure. Recently this type of the accidents are reported and the problem becomes an important research topic in LNG (Liquefied Natural Gas) Tanker and FPSO (Floating Production Storage Offloading) design. To predict the sloshing impact load, Morison’s formula could be used for a practical reason. But using the Morison formula may provide directly an inaccurate estimation for the impact load because this formula is based on the linear model in the present nonlinear dominating phenomena. In this study, the wave impact load on the structure is obtained by imposing the exact nonlinear free surface conditions numerically and compared with that predicted by Morison’s formula. As a numerical method, a three-dimensional free surface flow in a tank is formulated in the scope of potential flow theory with the nonlinear free-surface conditions. A finite-element method based on Hamilton’s principle is employed as a numerical scheme. The problem is treated as an initial-value problem. The nonlinear problem is numerically solved through an iterative method at each time step.
Trawl Gear Protection Within Platform Safety Zones
Authors: Fyrileiv Olav , Spiten Jo̸rn
Published: January 2009

This paper deals with the risk to human lives, installations and the environment that trawling activity within the platform safety zones may cause. Due to the high consequences associated with failures of pipelines and subsea installations in the vicinity of offshore platforms, the zone around (manned) platforms are in some design codes, such as the DNV-OS-F101 for submarine pipelines [1], defined as a safety zone. Such a zone implies that pipelines and risers are designed to a higher target probability of failure, i.e. an extra safety margin is incorporated. To further reduce the probability of failure and, hence, increase the safety, extreme load like trawl interference may be avoided by declaring the safety zone as a trawl-free zone. This means that no fishing gear, such as bottom trawl gear, shall intrude this zone. Because this zone is defined as a trawl free zone, it is common practice not to consider trawl loads within this area, i.e. pipelines and subsea installations are not necessarily designed as over-trawlable. The paradox is that in some areas with extensive trawling, the manoeuvring of trawlers may easily cause the bottom trawl gear to intrude the safety zone and thereby expose the trawler, its crew and the platform with its crew to significant risks. This paper discusses one case where a trawl caused some damage to subsea installations well within the safety zone. It is demonstrated how the bottom gear may intrude the safety zone as the trawler round the platform zone. Different measures to avoid this behaviour or remove/reduce the associated risk are also discussed with background in the real case.
Optimal Design and Portfolio Risk Management for Groups of Structures
Authors: Faber Michael Havbro , Maes Marc A. , Nishijima Kazuyoshi
Published: January 2009

The present paper addresses the problem of optimal design of portfolios of fixed offshore structures. A new framework for design is developed where the effect of dependency in the performance of structures subject to common extreme load events is taken into account in the design by inclusion of the follow-up consequences resulting from the simultaneous failure of several structures in the portfolio. First the special aspects of optimal design subject to follow-up consequences are addressed from the perspective of structures portfolio risk management. Thereafter the problem of optimal design of groups of structures is defined with special considerations to the assessment of the relation between the design, the probability density function of the life cycle benefits and the number of structures considered (in a group). Using this model basis the optimum design of fixed steel offshore platforms where the capacity of the structures against extreme wave loads can be expressed as function of the Reserve Strength Ratio (RSR) is considered. Thereafter parametric studies are conducted to illustrate the significance of the number of structures considered in a group, the correlation between the extreme loads acting on the different structures and the significance of including the follow-up consequences into the design optimization problem.
Effect of Uncertainties on the Reliability of Fatigue Damaged Systems
Authors: Silva-Gonza´lez Francisco L. , Heredia-Zavoni Ernesto
Published: January 2009

Fluctuating stresses and strains due to wave forces cause accumulated fatigue damage in tubular joints of marine platforms. Considering the uncertainties in the loads, material properties, initial crack sizes, and stress intensity factors, etc., may affect significantly the reliability assessment of marine jacket platforms. In this paper, we assessed the effect of uncertainties about such fatigue variables on the time evolution of the reliability of series and parallel systems considering correlation between failure modes. The fracture mechanics Paris-Erdogan model is used to model crack growth and a FORM method is used for computing the safety index. The uncertain variables analyzed are: initial crack size, material parameters C and m in the fracture mechanics model and the shape and scale parameters of the Weibull density function used for the long-term distribution of stress range.
Stochastic Analysis Method in Application of Longshore Sedimentation
Authors: Liu Defu , Zhang Mingxia , Lv Xiuyan
Published: January 2009

Huanghua is one of the important ports in China. During its constructing stage, Huanghua port encountered the heavy sedimentation after each typhoon or other storm weather processes. In the feasibility study, the predicted yearly amount of sedimentation is far less than that observed. In order to obtain the reasonable design amount of sedimentation, the stochastic analysis methods are involved in this paper to predict the total sedimentation of different design return periods with corresponding confidence intervals. For the prediction of typhoon or storm (wind speed and duration) induced sedimentation, the trivariate joint probability of wind speed, duration and corresponding sedimentation can be obtained by stochastic simulation technique based on the importance sampling procedure.
Accurate Assessment of Higher Order Wave Loads on Floating Structures
Authors: Teigen P. , Naess A.
Published: January 2009

The paper highlights the problem of accurate assessment of second order wave loads on floating structures, and the consequences for the extreme response of structures subjected to stochastic loading. Particular emphasis is put on discussing mesh size requirements and numerical convergence.
Investigation for Modeling of Sessile Organisms on Coastal Floating Structures
Authors: Tabeta Shigeru , Kinoshita Tsuguki , Kitazawa Daisuke , Fujino Masataka , Kato Takayoshi , Sasaki Akira , Iume Toshiyuki
Published: January 2009

Through the investigation about environmental impacts of Mega-Float, it is revealed that the effect of sessile organisms adhering on the floating structure is significant. However there had been little information about activities of the sessile organisms on floating structures and their influences on water and bottom quality. Therefore, some experiments were carried out to investigate the uncertain processes caused by the sessile organisms. An instrument called “Bell-jar”, which is composed of an enclosed container and several sensors for measuring water quality in it, was developed to measure the activities of sessile organisms on artificial bases set in Tokyo Bay. Through the experiments using Bell-jar, the consumption rate of dissolved oxygen and Chlorophyll-a, and emission rate of nutrients by the sessile organisms were measured. By fitting the model to these results, the parameters for activities of sessile organisms such as respiration rate and filtering rate were determined. The experiments have been carried out under various conditions of water temperature and salinity and it is clarified that the activities of sessile organisms very much depend on the water temperature and salinity. The behavior of particulate organic matters excreted from the sessile organisms is also investigated by laboratory experiments. These results were used to improving the model of sessile organisms, which is incorporated into the numerical ecosystem model for environmental impact assessment of very large floating structures.
High Energy X-Ray Inspection Services for In-Service NDE of Flexible Riser Piping
Authors: DePinna Mike , Owen Roger DeBaun , Simon Brett
Published: January 2009

High-energy X-ray Computed Tomography/Digital Radiography (CT/DR) technologies are being investigated in order to develop a significantly enhanced non-destructive examination (NDE) capability for in-service inspection of flexible risers. Statoil Research Center, in concert with U.S. and European manufacturers, have studied advanced industrial high-energy X-ray, CT/DR, and robotics systems for potential use in offshore oil & gas production facilities. The objective is to adapt these technologies for in-service NDE of flexible risers and end-fittings on FPSO vessels and TLP structures, as well as other configurations. Both topside and sub-sea versions of the device are envisioned. The device will use a miniature electron linear accelerator as the X-ray source. The CT/DR detector consists of an array of photodiodes and signal amplifiers, an advanced computer workstation, and integral robotics used to rotate and translate both the X-ray source and detector array. For topside applications, an external radiation shielding unit will be installed around the system. For sub-sea applications, the X-ray source, detector array and integral robotics will be mounted on a ‘clamping-walking’ robot that attaches to the outside of the flexible riser. The tool is to be installed on the riser by a large Remote Operated Vehicle (ROV), with control logic and power supply provided by cables embedded in the Tether Management System (TMS). Image data captured and transmitted to the workstation are processed, stored and displayed digitally. Reconstructed CT/DR X-ray images generated offshore can be rendered in 2D or 3D display, and transmitted to remote terminals anywhere in the world.
Statistical Analysis of Ocean Environmental Conditions With PTGEVD
Authors: Dong Sheng , Hao Xiaoli
Published: January 2009

Poisson Trivariate Gumbel Extreme Value Distribution (PTGEVD), a multivariate from of the Compound Extreme Value Distribution, is presented to solve for the ocean environmental design criteria in this paper. The proposed model is combined with a discrete distribution of storm frequency and a continuous trivariate extreme value distribution of environmental conditions simultaneously occurred in storm processes. Different from traditional univariate design method, the proposed design method with PTGEVD can reflect the combined effect of multi-loads on offshore structures and result in reasonable reduction of the design criteria. Validated with the synchronically measured significant wave heights, wind speeds and current velocities of 20 typhoon processes, PTGEVD model shows that it is easy to be applied and has considerable economic potential in the exploitation of ocean oil and gas, especially for marginal field.
Light Rail Vehicles and Running Safety
Authors: Swanson John D.
Published: January 2009

The basic standard US LRV structural designs are virtually unchanged from those adopted 25 years ago based on a modified European subway car. With only one exception, these have not been significantly updated for or adapted to the high levels of in-street running found more and more on new light rail systems or for increased passenger safety in general. Today in Europe, the overall structural design approach for LRVs is to absorb initial collision energy without any structural damage. To evaluate this approach, the four most common vehicle collision scenarios are first identified and quantified. Then European operational experience, particularly as regards accidents, is presented and analyzed. From these, we can see that further improvements to US rail vehicle design safety, especially to interior spaces, are both overdue and inevitable. Recent US LRV structural safety standard developments are considered and recommendations are proposed for incorporation into new light rail vehicle designs.
Short-Term Measurement of a Photovoltaic/Fuel Cell Remote Hybrid Power System at Golden Gate National Recreation Area
Authors: Walker Andy , Christensen Jim , Barker Greg , Rawlings Lyle
Published: January 2009

This paper reports short-term performance measurement of a hybrid photovoltaic/fuel cell power supply system at Kirby Cove Campground in Golden Gate National Recreation Area, California. The system operated reliably for two years from June 1999 to July 2001. During this period, the campground host load was met with a combination of solar power and power from the fuel cell. In August of 2001, reports of power outages justified an in-depth investigation. Data is reported over 13.5 days from September 2 to September 15, 2001. Over this period, energy delivered by the photovoltaic array totaled 42.82 kWh. Energy delivered by the fuel cell totaled 1.34 kWh, and net (out-in) energy from the battery totaled 6.82 kWh. After losses in the battery and inverter, energy delivered to the campground host totaled 34.94 kWh, an average of 2.6 kWh/day. Photovoltaic efficiency was measured at 8.9%. Fuel cell efficiency was measured at 42%, which is a typical value, but fuel cell power output was only 35 W instead of the 250 W rated power. Replacing a burnt fuse restored fuel cell power to 125 W, but several cells measured low voltage, and the fuel cell was removed for repair or replacement. Ordinarily, load in excess of the PV capability would be met by the fuel cell, and 22 cylinders of H2 (261 scf, 7,386 sl each) were consumed from April to August 2001. After failure of the fuel cell, load in excess of the solar capability resulted in discharged batteries and eight power outages totaling 48 hours in duration. Thus, overall system availability was 85% when relying only on solar power. This paper describes daily system operation in detail, presents component performance indicators, identifies causes of performance degradation, and provides recommendations for improvement.
On Indirectly Irradiated Solar Receiver-Reactors for High-Temperature Thermochemical Processes
Authors: Wieckert Christian , Meier Anton , Steinfeld Aldo
Published: January 2009

A solar receiver-reactor concept for high-temperature thermochemical applications involving gas and condensed phases is presented. It features two cavities in series. The inner cavity is an enclosure, e.g. made of graphite, with a small aperture to let in concentrated solar power. It serves as the solar receiver, radiant absorber, and radiant emitter. The outer cavity is a well-insulated enclosure containing the inner cavity. It serves as the reaction chamber and is subjected to thermal radiation from the inner cavity. The advantages of such a two-cavity reactor concept are outlined. A radiation heat transfer analysis based on the radiosity enclosure theory is formulated and results are presented in the form of generic curves that indicate the design constraints. High energy absorption efficiency can be achieved by minimizing the aperture area, by maximizing the size of the inner cavity, and by constructing it from a material of high emissivity.
Beam Characterization and Improvement With a Flux Mapping System for Dish Concentrators
Authors: Ulmer Steffen , Reinalter Wolfgang , Heller Peter , Lu¨pfert Eckhard , Martinez Diego
Published: January 2009

A flux mapping system able to measure the flux distribution of dish/Stirling systems in planes perpendicular to the optical axis was built and operated at the Plataforma Solar de Almeri´a (PSA). It uses the indirect measuring method with a water-cooled Lambertian target placed in the beam path and a CCD-camera mounted on the concentrator taking images of the brightness distribution of the focal spot. The calibration is made by calculating the total power coming from the dish and relating it to the integrated gray value over the whole measurement area. The system was successfully operated in a DISTAL II stretched membrane dish and in the new EURODISH in order to characterize their beams and improve the flux distribution on their receivers.
Texas Solar Radiation Database (TSRDB)
Authors: Vliet Gary C.
Published: January 2009

Solar radiation data have been acquired over approximately a five year period (1996 to present) at 15 sites in Texas (Texas Solar Radiation DataBase – TSRDB). These data are compared with comparable sites in the National Solar Radiation DataBase (NSRDB). Comparison of the TSRDB and NSRDB data for eleven (11) coincident or nearby locations show reasonably good agreement between the global horizontal values. Relative to the NSRDB, individual monthly average differences between the two sets range from −20 to +13%, and the annual averages varied from −9 to +8.5%, with positive values meaning the TSRDB values are higher. Overall, the TSRDB global horizontal data are about 2% lower than the NSRDB. However, there are considerable differences in the direct normal values, with the TSRDB values generally being higher. The monthly average differences ranged from −18 to +36%, and the average annual difference for the compared locations is about +5%. The greatest deviations for direct normal data are for coastal locations in the winter, with the three compared coastal locations exhibiting an average difference of about +30% for the combined months of December and January. Also, the TSRDB data for the Trans-Pecos region in west Texas exhibits significantly higher direct normal solar radiation throughout the year than does the NSRDB.
Effects of Lubricants on the Friction and Wear Properties of PTFE and POM
Authors: Benabdallah Habib S. , Wei Jianjun J.
Published: January 2009

The friction and wear properties of PTFE and POM were investigated using a ball-on-steel ring tester under dry conditions and conditions lubricated by paraffin and 10W-30 oils. SEM, EDAX, FT-IR and surface wettability techniques were used to characterize and assess the morphology and chemical composition of the original surfaces as well as wear track, transfer film and wear debris for different loads and speeds. Although the friction was high, similar behaviours to those reported were observed. The experimentally determined surface temperature of the plastic revealed optimum loading levels for each sliding speed at which the friction and wear rates become minimal and the thermal effect stabilizes. In boundary-like lubrication using both oils, friction and wear were significantly reduced with the exception of an increase in wear rate with load when POM was lubricated with 10W-30 oil. Surface analysis revealed that the formation of lubricious protective layers on the surfaces in contact is crucial to reducing friction and more importantly wear. FT-IR results confirmed that film transfer occurs in the case of POM.
Tribological Studies on Oscillating Bronze Bearings Lubricated With Environmentally Adapted Lubricants (EALs)
Authors: Ukonsaari Jan , Kassfeldt Elisabet
Published: January 2009

Different compositions of bronze materials are used for sliding bearings in various applications including those involving oscillatory motion and moderate temperatures. The compatibility of new environmentally adapted synthetic esters with different contacting surface materials is important to ensure good tribological performance. The present work deals with tribological studies on oscillatory journal bearings manufactured with three different compositions of bronze materials lubricated with EALs under boundary lubricated conditions. Under certain operating conditions, dissolution of alloying constituents from the bronze bearing material dissolute into the synthetic ester lubricant occur leading to the formation of a copper enriched bearing surface layer. Tin-bronze with synthetic ester lubricant showed more stable friction values and roughly ten times better wear results than the harder aluminium- and manganese-bronze and also outperformed the mineral oil under the same conditions.
Thermomechanical Analysis of Semi-Infinite Solid in Sliding Contact With a Fractal Surface
Authors: Gong Z.-Q. , Komvopoulos K.
Published: January 2009

A thermomechanical analysis is presented for semi-infinite elastic solid sliding against a rigid rough surface characterized by fractal geometry. A piecewise-linear distribution of the contact pressure was obtained by superposition of overlapping triangular pressure elements. The normal surface displacements due to the effects of contact pressure, shear traction, and thermoelastic distortion caused by frictional heating are incorporated in the influence coefficients of the matrix inversion method. Results for a smooth cylindrical surface sliding over a semi-infinite elastic solid demonstrate the accuracy of the analysis and provide reference for comparison with results obtained with the rough (fractal) surface. The effects of surface topography and interaction between neighboring asperity microcontacts on the surface and subsurface temperature rise and stress field of the elastic semi-infinite solid are discussed in the context of numerical results. The significance of frictional heating on the contact pressure, temperature rise, and stresses in interpreted in terms of the Peclet number and topography (fractal) parameters. The results provide insight into the likelihood for cracking and plastic flow at the surface due to the combined effects of mechanical and thermal surface tractions.
Experimental Identification of Elastic, Damping and Adhesion Forces in Collision of Spherical Sliders With Stationary Magnetic Disks
Authors: Ono Kyosuke , Oohara Satoshi
Published: January 2009

This paper deals with the experimental identification of elastic, damping and adhesion forces in the dynamic collision of a spherical slider with a stationary magnetic disk. We used rough Al2O3TiC and smooth glass spherical sliders with a radius of 1 mm, and magnetic disks with four different lubricant film thicknesses of 0, 1, 2, and 3 nm. We found that the Al2O3TiC slider shows ordinary approach and rebound processes, whereas the glass slider showed a velocity drop at the end of the rebound process when the lubricant thickness was 1, 2 and 3 nm. We identified the elastic force factors in the approaching and rebound processes, based on the Herztian contact theory, and the damping force factors based on a damping force model that is proportional to slider velocity and penetration depth (contact area). From the drop in velocity when the slider and disk separated, we found that the dynamic adhesion force is almost equal to the static pull-off force, except for with a 3nm lubricant thickness. The dynamic adhesion force with 3 nm lubricant thickness is significantly higher probably because of squeeze damping effect.
Wear Mechanisms of Untreated and Gamma Irradiated Ultra-High Molecular Weight Polyethylene for Total Joint Replacements
Authors: Zhou J. , Komvopoulos K.
Published: January 2009

Modification of the microstructure of ultra-high molecular weight polyethylene (UHMWPE) is essential for improving the wear resistance of orthopaedic implants. A common approach is to crosslink the polymer by gamma irradiation. The objective of this study was to examine the tribological behaviors of untreated and gamma irradiated UHMWPE under physiologically relevant contact conditions. Emphasis was given on the identification of the dominant wear mechanisms in the early stage of polymer wear. The irradiation dose exhibited as strong effect on the tribological properties of UHMWPE sliding against Co-Cr alloy in a bath of bovine serum. Transmission electron microscopy (TEM) and environmental scanning electron microscopy (ESEM) were used to examine the microstructure and morphology of the worn surfaces. Regularly spaced folds with average spacing depending on the irradiation dose (i.e., crosslink density) formed on the wear tracks. Surface folding was related to plastic flow and the degree of mobility of the crystalline lamellae. SEM and TEM results elucidated the roles of the crosslink density and crystalline lamellae in the wear process. Based on the experimental evidence, a deformation model was obtained that provides explanation for the dependence of surface folding on the crosslink density and lamellae reorientation during sliding.
Misalignment Effects on the Lubrication Behavior of Crankshaft Bearings
Authors: El-Butch A. M. A.
Published: January 2009

It is well known that the crankshaft bearing loading conditions are of complex nature. Also at high loads, elastic and thermal distortion of the bearing solids occurs, moreover, under these harsh conditions, misalignment can occur during operation. Due to the complexity of the problem, few researches have been done to study the dynamic performance characteristics of crankshaft bearing under such conditions. In the present work, it is intended to investigate the effect of bearing parameters on hydrodynamic pressure, film thickness and friction losses in the crankshaft main bearing considering shaft misalignment and bearing distortion. The main conclusion of the research is that, it is essential to consider misalignment as it is greatly deteriorating the film thickness leading to higher frictional losses. It is also found that the degree of misalignment is having little effect on the bearing mean load capacity.
Polyethylene Wear Debris From Hip Simulator Fluid Captured and Separated Using Bio-Ferrography
Authors: Meyer Donna M. , Tillinghast Adam , Hanumara Nevan C. , Franco Ana
Published: January 2009

This paper describes an experimental method, Bio-Ferrography, to separate ultra high molecular weight polyethylene (UHMWPE) wear debris, generated in hip simulators, from bovine serum lubricating fluid. A total of 54 experiments were performed in which an enzyme digestion “cocktail” was developed and used to clean the bovine serum samples of extraneous sugars, proteins and lipids that interfere with the UHMWPE particle separation. Erbium chloride was used to marginally magnetize particles in the fluid prior to passing through the ferrographic device. The particles were captured and separated from the fluid by traversing the treated serum across a magnetic gap of a bio-ferrograph. Morphology of the captured and separated wear debris was compared with particles from samples of fluid filtered through a paper sieve arrangement with pores of 0.05 micrometers in diameter. The UHMWPE wear debris collected using the described experimental method, were found to be between 0.1 and 20 micrometers in diameter with spherical and pill-shaped particles. The filtered UHMWPE particles were also in the same size range as the debris separated using bio-ferrography, 0.1 to 20 micrometers. To show that the experimental method captured UHMWPE particles, the spectra of the chemical composition of UHMWPE from an acetabular cup insert of a hip implant and of UHMWPE particles separated using Bio-Ferrography were compared and found to be the same. To further demonstrate that polyethylene could be captured and separated through the experimental method, manufactured polyethylene microspheres in the diameter range of 3 to 45 micrometers, were captured and separated using the bio-ferrographic process.
In-Situ Tribological Properties Monitoring and Chemical Mechanical Characterization of Planarization Process
Authors: Sikder Arun , Gitis Norm , Vinogradov Michael , Daugela Antanas
Published: January 2009

For faster signal propagation in integrated circuits, new materials with lower dielectric constant (low-k) values are required with copper metal lines. Although integration of low-k materials (k<3.0) has been demonstrated, but ultra low-k materials possess many challenges due to their poor mechanical integrity and weak adhesion to other interconnects. During chemical mechanical planarization (CMP) generation of several defects including delamination of low-k materials is severe problem in the integration of these materials. Different slurries and pad introduces different levels of defect and also batch-to-batch variation in consumables is often makes process more difficult. In this study we have investigated the tribological properties of CMP pad and wafer interface while monitoring coefficient of friction and acoustic emission data. Signals are analyzed in order to online defect monitoring, batch-to-batch consumable variations and different consumables effects.
Continuous Presence of Noroviruses and Sapoviruses in Raw Sewage Reflects Infections among Inhabitants of Toyama, Japan (2006 to 2008)
Authors: Iwai Masae , Hasegawa Sumiyo , Obara Mayumi , Nakamura Kazuya , Horimoto Eiji , Takizawa Takenori , Kurata Takeshi , Sogen Shun-ichi , Shiraki Kimiyasu
Published: January 2009

Various genotypes of norovirus (NoV) (genogroup I genotype 1 [GI.1], -2, -4, -5, -8, -11, -12, and -14; GII.3, -4, -6, -7, -10, -13, -14, and -15), and sapovirus (SaV) (GI.1 and GI.2, GII.1, and GIV.1) were detected from raw sewage from April 2006 to March 2008, while limited numbers of genotypes of NoV (GI.8, GII.4, GII.6, and GII.13) and SaV (GII.3 and GIV.1) and of NoV (GII.4, GII.7, and GII.13) were detected from clinical cases and healthy children, respectively. During the winter 2006 to 2008, a large number of sporadic gastroenteritis outbreaks and many outbreaks caused by NoV GII.4 occurred among inhabitants in Toyama, Japan. The copy number of genomes of NoV GII detected from raw sewage changed in relation to the number of outbreaks. NoV strains of the same genotypes observed in both raw sewage and human specimens belonged to the same cluster by phylogenetic analysis and had almost identical nucleotide sequences among each genotype. These data suggest that NoVs and SaVs detected from raw sewage reflect the viruses circulating in the community, irrespective of symptoms, and that subclinical infections of NoV are common in Japan. Combined surveys of raw sewage with those of clinical cases help us to understand the relationship between infection of these viruses and gastroenteritis.
Characterization of a Monoclonal Antibody Directed against
Salmonella enterica
Serovar Typhimurium and Serovar [4,5,12:i:−]
Authors: Rementeria A. , Vivanco A. B. , Ramirez A. , Hernando F. L. , Bikandi J. , Herrera-León S. , Echeita A. , Garaizar J.
Published: January 2009

Flagellar extracts of
Salmonella enterica
serovars expressing phase 2 H1 antigenic complex (H:1,2, H:1,5, H:1,6, and H:1,7) and a mutant flagellin obtained by site-directed mutagenesis of the
fljB
gene from serovar Typhimurium at codon 218, transforming threonine to alanine, expressed in
Escherichia coli
(
fljB218

A

) were used to analyze the H1 antigenic complex. Cross-reactions were detected by Western blotting and dot blotting using commercial polyclonal antibodies against the different wild-type extracts and mutant FljB218
A
. Therefore, we produced a monoclonal antibody (MAb), 23D4, isotyped as immunoglobulin M, against H:1,2
S. enterica
serovar Typhimurium flagellin. The mutant flagellin was not recognized by this MAb. When a large number of phase 1 and phase 2 flagellin antigens of different serovars were used to characterize the 23D4 MAb, only extracts of serovars Typhimurium and [4,5,12:i:−] reacted. The protein composition of phase 1 and phase 2 extracts and highly purified H:1,2 flagellin from serovar Typhimurium strain LT2 and extract of strain 286 (serovar [4,5,12:i:−]), which reacted with the MAb, was studied. Phase 2 flagellin (FljB
H:1,2
) was detected in phase 1 and phase 2 flagellar heat extracts of serovar Typhimurium and was the single protein identified in all spots of purified H:1,2 flagellin. FliC, FlgK, and other proteins were detected in some immunoreactive spots and in the flagellar extract of serovar [4,5,12:i:−]. Immunoelectron microscopy of complete bacteria with 23D4 showed MAb attachment at the base of flagella, although the MAb failed to recognize the filament of flagella. Nevertheless, the results obtained by the other immunological tests (enzyme-linked immunosorbent assay, Western blotting, and dot blotting) indicate a reaction against flagellins. The epitopes could also be shared by other proteins on spots where FljB is not present, such as aminopeptidase B, isocitrate lyase, InvE, EF-TuA, enolase, DnaK, and others. In conclusion, MAb 23D4 can be useful for detection and diagnostic purposes of
S. enterica
serovar Typhimurium and serovar [4,5,12:i:−] and could be also helpful for epitope characterization of flagellum-associated antigens.
Deletion of the Protein Kinase A Regulatory Subunit Leads to Deregulation of Mitochondrial Activation and Nuclear Duplication inAspergillus fumigatus
Authors: Fuller Kevin K. , Zhao Wei , Askew David S. , Rhodes Judith C.
Published: January 2009

Proper regulation of the cyclic AMP-dependent protein kinase (PKA) pathway is required for normal growth and development in many fungi. We have reported that deletion of the PKA regulatory subunit gene,pkaR, inAspergillus fumigatusleads to defects in germination and a hypersensitivity of conidia to oxidative stress. In this study, we further analyzed the defects of ΔpkaRconidia and found that a large proportion were abnormally larger than wild type. Because swelling and increased susceptibility to oxidative stress are characteristic of germinating conidia, we analyzed the metabolic activity of the conidia by mitochondrial staining. Whereas it required 4 h in rich medium for wild-type mitochondria to become active, ΔpkaRconidia harbored active mitochondria in the absence of a germinant. Furthermore, conidia of the mutant showed a dramatic loss in viability upon short-term storage in water, indicating starvation-induced death. Taken together, our data suggest that PKA activity regulates metabolic activation of resting conidia. Additionally, the ΔpkaRmutant displayed an abnormal abundance of hyphal nuclei and had increased transcript levels of several cell cycle regulatory genes. These data indicate an important role for PKA in the nuclear duplication cycle ofA. fumigatus.
Adenovirus-Mediated Delivery of an Anti-V Antigen Monoclonal Antibody Protects Mice against a Lethal
Yersinia pestis
Challenge
Authors: Sofer-Podesta Carolina , Ang John , Hackett Neil R. , Senina Svetlana , Perlin David , Crystal Ronald G. , Boyer Julie L.
Published: January 2009

Pneumonic plague, caused by inhalation of
Yersinia pestis
, represents a major bioterrorism threat for which no vaccine is available. Based on the knowledge that genetic delivery of monoclonal antibodies (MAbs) with adenovirus (Ad) gene transfer vectors results in rapid, high-level antibody expression, we evaluated the hypothesis that Ad-mediated delivery of a neutralizing antibody directed against the
Y. pestis
V antigen would protect mice against a
Y. pestis
challenge. MAbs specific for the
Y. pestis
V antigen were generated, and the most effective in protecting mice against a lethal intranasal
Y. pestis
challenge was chosen for further study. The coding sequences for the heavy and light chains were isolated from the corresponding hybridoma and inserted into a replication-defective serotype 5 human Ad gene transfer vector (AdαV). Western analysis of AdαV-infected cell supernatants demonstrated completely assembled antibodies reactive with V antigen. Following AdαV administration to mice, high levels of anti-V antigen antibody titers were detectable as early as 1 day postadministration, peaked by day 3, and remained detectable through a 12-week time course. When animals that received AdαV were challenged with
Y. pestis
at day 4 post-AdαV administration, 80% of the animals were protected, while 0% of control animals survived (
P
< 0.01). Ad-mediated delivery of a V antigen-neutralizing antibody is an effective therapy against plague in experimental animals and could be developed as a rapidly acting antiplague therapeutic.
The Genome of
Thermosipho africanus
TCF52B: Lateral Genetic Connections to the
Firmicutes
and
Archaea
Authors: Nesbø Camilla L. , Bapteste Eric , Curtis Bruce , Dahle Håkon , Lopez Philippe , Macleod Dave , Dlutek Marlena , Bowman Sharen , Zhaxybayeva Olga , Birkeland Nils-Kåre , Doolittle W. Ford
Published: January 2009

Lateral gene transfers (LGT) (also called horizontal gene transfers) have been a major force shaping the
Thermosipho africanus
TCF52B genome, whose sequence we describe here.
Firmicutes
emerge as the principal LGT partner. Twenty-six percent of phylogenetic trees suggest LGT with this group, while 13% of the open reading frames indicate LGT with
Archaea
.
Survival of vendace (Coregonus albula) escaping from a trawl cod end
Authors: Suuronen Petri , Turunen Timo , Kiviniemi Marko , Karjalainen Juha
Published: January 2009

Many young (0 group) vendace (Coregonus albula) are thought to die after passing through trawl cod ends during commercial vendace fishery in Finnish lakes. Survival of 2- to 4-month-old vendace (5–10 cm) after escaping from a 24-mm square mesh trawl cod end was therefore studied in Lake Puulavesi, Finland, during July–August 1993. Escapees were collected in a hooped netting cage that was released from the cod end after the tow, closed, and left at the depth of capture for 3–7 days. The data consist of 59 cagings. On average, 50% of the escaped vendace died, although mortality varied considerably. Most mortality occurred during the first day after escaping. Hauls conducted in the late evening and at night were accompanied by the highest mortality (60–80%). Mortality was 30–40% in the afternoon and early evening hauls. Generally, higher mortality was observed in August than in July. Comparisons with caged fish caught by a purse seine suggested that the experimental procedure did not substantially contribute to the observed total mortality of escapees. Scale loss and exhaustion experienced by vendace during trawl capture may have caused the rapid death of escapees through loss of osmoregulatory control.
Direct and indirect effects of predation by a calanoid copepod (subgenus: Hesperodiaptomus) and of nytrients in a fishless alpine lake
Authors: Paul A. J. , Schindler D. W. , Hardie A. K. , Leavitt P. R.
Published: January 2009

The calanoid copepod Diaptomus (subgenus: Hesperodiaptomus) arcticus is a keystone predator in fishless alpine lakes of the Canadian Rockies. We quantified the effects of predation by D. arcticus on other copepods, rotifers, and algae in large mesocosm experiments (2250 L) using two levels of predator (present and absent) and two levels of nutrient addition (ambient and 4×). Standing stocks of algal taxa were assessed by high performance liquid chromatography of phytoplankton pigments. Diaptomus arcticus suppressed the biomass of rotifers and cyclopoid nauplii at both nutrient levels. The indirect effect of D. arcticus on algal biomass was minimal under ambient nutrient conditions, possibly owing to high rates of nutrient recycling by grazers. Biomass of algae, cyclopoid nauplii, and rotifers responded positively to nutrient additions. Nutrient addition increased algal standing crop 2- to 4-fold and changed dominance from diatoms and chrysophytes to blue-green algae. Diaptomus arcticus accelerated these changes, possibly by eliminating grazing by rotifers. These results suggest that in the absence of increased nutrients D. arcticus directly limits the biomass of herbivorous zooplankton but the indirect effect on phytoplankton is minimal.
Growth of the Pacific pomfret, Brama japonica: a comparison between otolith and length–frequency (MULTIFAN) analysis
Authors: Bigelow Keith A. , Jones Juble T. , DiNardo Gerard T.
Published: January 2009

Age and growth of the Pacific pomfret, Brama japonica, were independently estimated with presumed daily increments within otolith microstructure and MULTIFAN analysis of length–frequency distributions obtained from drift net fisheries. Likelihood ratio tests detected significant differences between sexes and geographic areas in von Bertalanffy parameter estimates from otolith analysis. Otolith interpretations indicated that the species is short lived (age 3+), fast growing (growth coefficient (K) > 1.1), and fully recruited to the North Pacific squid drift net fishery at < 1 yr old. Back-calculated hatching dates indicate a protracted spawning period. MULTIFAN models fit the length–frequency data with an assumption of both annual and biannual recruitment. Growth parameter estimates were asymptotic fork length (FL∞) = 49.9 cm, K = 0.57 for an annual cohort model, and FL∞ = 49.4 cm, K = 1.0 for a biannual cohort model. The growth model derived from otolith increment counts is closer to the MULTIFAN model that assumes biannual length–frequency modes, rather than annual modes.
EFFICIENT COMBINED SCHEDULING OF HARD AND SOFT REAL-TIME TASKS IN MULTIPROCESSOR SYSTEMS UNDER A PROCESSING POWER-SHARE STRATEGY
Authors: ABDEL MAKSOUD EHAB Y.
Published: January 2009

Increasingly, real-time systems are being used in applications that contain tasks that have deadlines and require predictable performance. Many complex real-time applications require modern operating systems capable of scheduling multiple classes of tasks in an integrated way. These applications require scheduling that result in high utilization of available processing power to accommodate as many tasks as possible while satisfying the required deadlines of each task. In this paper, we propose a combined heuristic approach to schedule a set of independent soft and hard real-time tasks in multiprocessor computing systems. Each of these tasks is characterized by its arrival time, deadline and required processing power. The proposed approach distributes the total available processing power of any processor, if it is needed and possible, among more than one task, while ensuring that hard real-time tasks are given higher priority and enough processing power to meet deadlines. This strategy can be used as a tool to efficiently guide scheduling processes. In addition, it can help to optimize processor utilization and maintain higher success ratios by maximizing the schedulability of soft tasks without jeopardizing the schedulability of hard tasks.