bluuebunny/crossref_metadata_2025 huggingface dataset:
Combined Loading Capacity of Pipelines: Approaches Towards the Compressive Strain Limit
Authors: Karbasian Hossein , Zimmermann Steffen , Marewski Ulrich , Steiner Michael
Published: July 2013

This paper presents details on the load bearing capacity of pipelines subjected to combined loading (internal pressure, axial and bending load) based on the findings of a recent research project of the European Pipeline Research Group (EPRG). Firstly, the failure mechanisms of line pipe under combined loading, which depend on local geometry, material characteristics as well as local and global applied loading, are characterized. Afterwards, differences between laboratory testing and the real-life situation of pipelines subjected to combined loading are described. Here, optimal boundary conditions for realistic testing are defined. Finally, a large variety of modelling approaches, specifically dedicated to combined loading experimental data from 59 full-scale tests on line pipe joints have been analysed. The relevant parameters in the analysis of buckling behavior of the pipes were: actual material properties, boundary conditions, failure phenomena and strain at failure, with the final aim to issue recommendations with regard to the selection of modelling approaches, sensitivity towards input parameters as well as strain threshold values. For the prediction of the limit pipe deformation a large selection of equations suggested by various authors in terms of critical bending moment, critical strain and critical stress for various loading conditions were considered. The methods differ in solution methodology (analytical vs. numerical), in the definition of material behavior (elastic, elastic-plastic) and in the definition of critical conditions and critical points. Then, the different types of buckling as a function of pipe geometry were characterized. Finally, the buckling behavior of an actual bending test was simulated using measured input data.
Application of Three Methods in Determining the Effectiveness of Surge Protection Systems in Gas Compressor Stations
Authors: Botros K. K. , Bakker D.
Published: July 2013

Compression Systems are designed and operated in a manner to eliminate or minimize the potential for surge, which is a dynamic instability that is very detrimental to the integrity of the unit. Compressor surge can occur when compressors are subjected to rapid transients such as one following emergency shutdown (ESD) or power failure. To prevent this from occurring, compressor stations are designed with recycle systems and special types of recycle valves, which are required to open upon ESD. These recycle valves must have specific characteristics to cope with such fast transients and protect the compressor for undergoing surge. This paper describes three methods for determining the effectiveness of any specific recycle system and recycle valve characteristics. These three methods are: i) the concept of the Inertia number, ii) a simplified method based on system impedance, and iii) full dynamic simulation of the compression system. These three methods are applied to a high pressure ratio (up to 3.5) natural gas compressor station involving very high volume of piping and equipment contained within the recycle loop. There is a heat exchanger to utilize the heat of compression to heat the condensate separated downstream in the discharge scrubber, two large aerial coolers to cool the high temperature discharge gas from the compressor, and the discharge scrubber itself. This equipment and associated large volume capacitance contained therein presented a significant challenge and demand on the surge suppression system in all aspects of operation; particularly during ESD. Results are presented from all three methods which show the consistency and complementary nature of these methods.
Integrity of Pipeline in Area of Mine Subsidence
Authors: Zhang Fan , Liu Ming , Wang Yong-Yi , Yu Zhifeng , Tong Lei
Published: July 2013

Ground subsidence can threaten the integrity of buried pipelines in areas with prior and on-going mining activities. The integrity can be assessed by comparing the strain demand and the strain capacity. The Tensile Strain Capacity (TSC) of the pipeline is dominated by the girth welds due to their relatively inferior property in comparison to the base pipe materials. Parametric models developed at CRES for US DOT and PRCI allow the evaluation of girth welds TSC based on pipe dimensions, base material and weld properties and flaw size. The local buckling of the pipeline under compressive or bending loads determines the Compressive Strain Capacity (CSC). Three existing standards are used to evaluate CSC, including DNV OS-F101, CSA Z662 and API RP 1111. The strain demand analysis of the pipeline under multiple subsidence scenarios is presented in a companion paper. The strain demand is compared with TSC and CSC separately to evaluate the pipeline integrity. The use of CRES TSC models for selecting a variety of design and material parameters to improve TSC is illustrated.
An Approach for Evaluating the Integrity of Plain Dents Reported by In-Line Inspection Tools
Authors: Bratton Joseph P. , Alexander Tom , Bubenik Thomas A. , Finneran Shane , Heggen Hans Olav
Published: July 2013

Current federal regulations in the U.S. require excavation of plain dents identified through in-line inspection surveys based primarily on depth. Industry experience, and previous research, has shown that the depth of the dent, alone, is not sufficient to assess dent severity and that releases could occur at dents below the excavation threshold (Dawson, 2006). Canada’s National Energy Board released a safety advisory on June 18, 2010, to all companies under their jurisdiction regarding two incidents involving shallow dents. The safety advisory stated that all integrity management programs should be reviewed and updated where appropriate to address the threat posed by shallow dents. Similar incidents have raised awareness in the United States and elsewhere around the world.

This paper focuses on the fitness for service of dents identified by in-line inspection surveys. The fitness for service assessment provides an estimated remaining life of a dent based on the geometry of the dent and current pressure cycling of the pipeline. Dynamic pressure cycling at each dent location is estimated using the upstream and downstream pressure cycle data, elevation, and distance along the pipe. The dynamic pressure cycle data at each dent is then converted into equivalent stress cycles based on the results of rainflow cycle counting.

Maximum strain levels of the dents are calculated based on the geometry of the dent as determined by radial sensor measurements from the in-line inspection survey. The combination of assessment methods provides estimates of remaining fatigue life and peak strain which can be used for prioritizing the investigation and remediation of plain dents in pipelines.

Finite element analysis (FEA) is performed for one dent to calculate the maximum strain levels and identify stress concentration areas. These results are compared with the values applied during the fitness for service assessment to validate the accuracy and conservatism of the calculation methods used. An idealized dent will be analyzed to investigate the strain calculations in ASME B31.8 and localize maximum strain values.
Simulation of Ductile Crack Propagation in High-Strength Pipeline Steel Using Damage Models
Authors: Nonn Aida , Kalwa Christoph
Published: July 2013

The performance of engineering design of high-strength steel pipelines has revealed the necessity to revise current design procedures. Therefore, an improved and detailed comprehension of fracture mechanisms and development of failure prediction tools are required in order to derive new design criteria. In last decades the most successful failure prediction tools for steel structures subjected to various type of loading can be encountered in the field of damage mechanics. This paper aims to describe ductile fracture behavior of high-strength steel pipelines by applying three different damage models, Gurson-Tvergaard-Needelman (GTN), Fracture Locus Curve (FLC) and Cohesive Zone (CZ). These models are evaluated regarding their capability to estimate ductile crack propagation in laboratory specimens and linepipe components without adjusting the calibrated parameters. It can be shown that appropriate parameter sets can be identified to reproduce load-deformation and fracture resistance curves accurately. The strain rate effect on the fracture behavior is examined by dynamic tests on the BDWT specimens. Finally, the shortcomings of the applied models are pointed out with the reference to possible extensions and modifications.
Recommended ITP for the Quality Assurance of Skelp-End Welds in Spiral Pipes
Authors: Wang Yong-Yi , Liu Ming , Rapp Steve , Collins Laurie
Published: July 2013

API 5L allows skelp-end welds (SEWs) in finished pipes with some restriction on their position relative to the pipe ends. However, the overall acceptance of SEWs by the pipeline industry is spotty. For large diameter pipes, there could be one SEW for every five to seven joints of pipes. Therefore, allowing SEWs in finished pipes offers meaningful economic advantages to both pipe suppliers and purchasers when the quality of the SEWs can be assured.

A joint industry project (JIP) was formed to develop uniformly acceptable inspection and test plans (ITPs) for SEWs. The JIP members included the five linepipe manufacturers and six pipeline operators. The ITPs were developed through two parallel processes: (1) fitness-for-service analysis of the SEWs under a variety of loading conditions expected in the entire service life of a pipeline, and (2) consensus building based on the best practice and quality control protocols. The JIP group reviewed the suitability of existing QA procedures for SEWs and sought to provide users further assurance by developing supplemental QA/QC procedures. The ITPs contain additional provisions to supplement the requirements of the accepted industry standards, such as API 5L and CSA Z245.1. They incorporated specific quality control measures that address concerns in certain perceived weak points of SEWs, including the effects of coil-end properties, weld quality at T-joints, and open-root forming of the partial-penetration ID weld.

This paper summarizes the deliberation and recommended resolution of several key issues related to the perceived quality concerns of SEWs. A companion paper covers the fitness-for-service analysis of SEWs [1]. The project group, led by respective organizations of the authors, is working with API 5L committee to adopt some of the recommendations in the future revisions of API 5L.
Maximum Likelihood Approach to State Estimation in Online Pipeline Models
Authors: Modisette Jason P.
Published: July 2013

Hydraulic models of pipelines driven by SCADA usually have many more pressure and flow measurements available that are needed as boundary conditions of the underlying model. These extra measurements can be used to improve the estimate of the true state of the pipeline and to give the hydraulic model some resistance to measurement noise. The process of merging the available SCADA into a form the model can use is called “state estimation.”

A new technique for state estimation based on a maximum-likelihood estimate of the state of the pipeline constrained by the underlying physics will be presented. This method, which will be referred to as Maximum Likelihood State Estimation (MLSE), will be justified by comparison with two traditional methods of state estimation in use in the industry, the approach of breaking the pipeline up into multiple models with pressure boundaries and then rectifying the flows, and the Equal Error Fractions (EEF) method of Van der Hoeven [1].

An example of the application of this approach to a real-world pipeline will also be presented, with performance data as well as some of the deficiencies that were found and how they were corrected.
Cyclic Pressure Testing a Section of 34” Pipe Repaired Using the PETROSLEEVE Technology to Determine the Effect on a 50% Crack
Authors: Wang Rick , Kania Richard , Smyth Robert J. , Smyth Ian R.
Published: July 2013

TransCanada Pipelines operates a large mainline pipeline transportation system. Engineering analysis and severe testing was performed to confirm that the PETROSLEEVE© Steel Compression Reinforcement Technology would arrest crack extension in large diameter pipe.

This testing involved putting a 50% crack into a section of 862 mm diameter, 9.5mm wall thickness grade 448 pipe. Then a compression sleeve was installed while the pipe was pressurized to 3800 kPa (38% SMYS). Following sleeve installation, the test vessel was subjected to 9000 cycles 7880 to 2960 kPa (80%–30% SMYS); 200 cycles 7800 to 0 kPa (80%–0% SMYS); hold pressures of 8870 kPa (90% SMYS) for 4 hours and 10840 kPa (110% SMYS) for 2 hours.

Following the cyclic pressuring, the crack was metallurgically inspected. It was reported by third party inspection that the compression sleeve reinforcement “can effectively suppress fatigue crack growth of an axial flaw (100mm long × 50% of the wall thickness deep) in the API X65 pipe.”

This paper reviews the engineering and cyclic testing undertaken.
Trapped Water Flushed by Flowing Oil in Upward-Inclined Oil Pipelines
Authors: Xu Guangli , Cai Liangxue , Ullmann Amos , Brauner Neima
Published: July 2013

Pipe-line corrosion is of a major concern in the transportation of crude oil and natural gas. The corrosion is caused by the presence of water in contact with the walls. Following water-tests and/or shut-down, small amounts of water tend to accumulate at low sections along the pipe line. Flushing out of the water from the pipe by the oil flow is required to avoid damages in the pipeline. From a practical point of view, the minimal oil flow rate required for displacement and flush-out of the accumulated water by the oil flow has to be determined.

Experimental study, mechanistic models and numerical simulations are used to investigate the characteristics of water displacement by oil flow in hilly terrain pipelines. Various mechanisms for the onset of water displacement from a lower (horizontal) section into an upward inclined section are considered and the associated minimal (critical) oil-flow rate for the water displacement is evaluated. For oil-flow rates exceeding the critical value, the possible patterns of water movement in the inclined pipe are examined.
Detection and Mitigation of AC Interference on 200km Pipeline
Authors: Du Yanxia , Jiang Zitao , Lu Minxu
Published: July 2013

The AC interference on pipelines caused by nearby HVAC power lines and electrified railways can lead to electric shock hazard and AC corrosion, which threatens the safety of pipeline and has attracted more and more attention. A 300km-long pipeline in the north of China is close to many HVAC power lines and electrified railways and there exists a high risk of AC interference. A detection of AC interference has been done along the pipeline and the results indicate that AC interference is severe due to high AC voltage and AC current density. The mitigation scheme of the pipeline is designed with the aid of computer simulation software, based on which the mitigations are constructed. The field measurements show that the mitigation effect is good.
The Effect of Microstructure on Tensile Behaviour of X80 Microalloyed Steel
Authors: Jonsson Katherine , Ivey Douglas G. , Henein Hani , Nafisi Shahrooz , Collins Laurie , Garcin Thomas , Poole Warren
Published: July 2013

A high degree of work hardening is desirable for steels to be employed in strain-based pipeline designs. In an effort to enhance work hardening characteristics, this study was conducted to determine the effect of thermal treatment on microstructural development and the subsequent relationship between microstructure and tensile behaviour of high strength microalloyed line pipe steel. A series of thermal schedules was applied to X80 steel samples using a Gleeble thermo-mechanical simulator in order to generate a variety of microstructures. The microstructures were quantified by calculating the phase fraction of individual phases using scanning electron microscopy (SEM). A focused ion beam (FIB) instrument was used to prepare electron transparent samples of specific grains that were characterized using transmission electron microscopy (TEM). The X80 microstructures were composed mostly of bainitic and ferritic grains with isolated pockets of martensite and M-A islands due to local carbon segregation. The effect of thermal treatment on microstructural evolution was determined based on varying the interrupt temperature, re-heat temperature and hold time at elevated temperatures. The overall effect of microstructure on the mechanical properties was evaluated, with a particular focus on hardness values and the shape of the stress-strain curves. The effect of thermal history and microstructure development on the work hardening characteristics was also determined.
Corrosion Behavior of Novel Cr2MoNbTi Pipeline Steel in CO2 Environment
Authors: Zhang Wenliang , Xu Lining , Guo Shaoqiang , Zhang Lei , Lu Minxu , Zhang Yunan
Published: July 2013

CO2 corrosion is frequently encountered in oil and gas industry. The search for new sources of oil and gas has pushed the operational activities to harsher environment and this requires new tubing and pipeline materials which can endure tough circumstances. Low alloy steel containing Chromium, which fills the gap between carbon steels and corrosion resistant alloys in terms of cost and corrosion resistance, has aroused significant interest from steel enterprises and scholars. At present, these studies mainly focus on 3%–5%Cr steel, and little study concerns the 2%Cr steel, which is more economic and weldable. In this paper, novel Cr2MoNbTi steel was developed and the microstructure and mechanical properties were studied. Corrosion behavior of the Cr2MoNbTi steel immersed in the CO2-containing solutions, which corresponded to the environment of bottom-of-line corrosion (BLC), was studied using high temperature-high pressure autoclave. In addition, dynamic high temperature-high pressure condensation autoclave was employed to simulate the top-of-line corrosion (TLC) environment and the corrosion behavior of the Cr2MoNbTi steel under wet gas environment was investigated. The composition and morphology of the corrosion scale were characterized by energy dispersive spectroscopy and scanning electron microscopy analyses. The results show that the Cr2MoNbTi steel exhibited uniform corrosion and presented good resistance to CO2 corrosion compared with X65 pipeline steel.
Modeling the Effect of Material Behavior and Mild Thermal Treatments on Collapse Resistance of UOE Pipes
Authors: Serebrinsky Santiago , Mantovano Luciano , de Souza Marcos , Valdez Martín , Ernst Hugo , Chad Luis
Published: July 2013

Oil exploration and production of offshore sources is continuously shifting towards increasing depths and more severe environmental conditions. Ultra deep waters are an objective in, e.g., the pre-salt layer off the Brazilian coast and in the Gulf of Mexico. Under these conditions, resistance to collapse of pipelines is a main concern. Increasing the collapse pressure pc is thus a primary objective, which would lead to a reduction of material and installation costs.

To increase pc, it is fundamental to understand which variables affect it, and how to control these variables. For instance, it is well known that ovality, residual stresses, and material constitutive behavior have a direct effect on pc. Current efforts for improving pc of large diameter UOE pipes include an increase in flow stress by the application of a thermal cycle, similar to those typical of coating processes. These thermal treatments recover at least part of the early yielding due to the Bauschinger effect that develops during the collapse test, after the expansion stage.

Predictive modeling of pc, based on an appropriate set of input variables, allows for an adequate design of deep- and ultra-deep water projects. In the present work, an assessment by finite element analysis of the requirements on material characterization tests for a reliable prediction of pc has been performed. The most appropriate testing direction is the transverse compression. Moreover, since for large diameter pipes the plastic strain levels attained at collapse are often below 0.2%, the sample should allow for an accurate determination of compression behavior in this very low deformation range. This is particularly relevant for cold-formed pipes, as with the UOE process. Based on these guidelines, a testing sample geometry and compression data processing methodology has been designed.

The methodology has been applied to a series of UOE processed pipes that had been thermally treated. On one hand, compression samples were extracted and used for the FE calculation of pc. On the other hand, collapse tests were performed on the same pipes. Both the absolute values of pc, and the enhancement of pc due to thermal cycling, were accurately predicted.

In addition, both the flow stress after thermal cycling, and the measured pc values, clearly show that the fabrication factor αfab used in the standard DNV OS-F101 should be set to αfab≥1 for an adequate rating of the pipes.
Risk Based Design Solution for Routing a High Pressure Gas Transmission Pipeline Through a Region of Geological Instability
Authors: Taylor Mike , Jandu Chas , McCallum Marcus , Northing Ray
Published: July 2013

If present, regions of geological instability are normally identified during the route selection study and a route through such locations will normally be rejected if a suitably practicable alternative route can be found. Therefore the consequential effects of a landslip on pipeline integrity rarely need to be considered. However, when an alternate route is not practicable, then a means of negotiating the landslip zone in a safe manner needs to be determined and adopted. One means of negotiating a landslip zone is to route the pipeline well beneath the slope using techniques such as horizontal directional drilling (HDD). However, the success of an HDD cannot be guaranteed in such situations and hence alternative solutions need to be considered even if only as a back-up. This paper describes a technique that was developed by a major UK high pressure gas pipeline operator with support from Andrew Francis & Associates Ltd (AFAA) to achieve a viable engineering alternative to HDD.

The technique is based on a combination of structural reliability analysis (SRA) and quantified risk assessment (QRA) which was developed by modifying and customising an approach that the operator had developed and used previously for demonstrating the safe operation of gas transmission pipelines at design factors in excess of 0.72. The overall objective is to demonstrate that all associated risks have been reduced to levels that can be regarded ‘As Low As Reasonably Practicable’ (ALARP).

SRA begins with an identification of all credible failure causes and these are then analysed using a combination of structural mechanics based techniques and probability theory to determine failure frequencies. For the present application, significant attention was given to the interaction between the moving land mass and the pipeline using 3-dimensional finite element analysis. The analyses were performed for a range of credible scenarios assuming a range of soil properties to establish the likelihood that failure would occur in the event of a land slide. These were then combined with an assessment of the event frequency to determine estimates of the failure frequency. Having established ‘raw’ failure frequencies, the model was developed further to investigate the effects of introducing mitigating methods to reduce the failure frequencies, and hence risks, to levels that could be regarded as ALARP.

The paper describes the philosophy and the salient features of the approach and illustrates the application using a case study.
X-Ray Diffraction Study of Microstructural Changes During Fatigue Damage Initiation in Steel Pipes
Authors: Pinheiro Bianca , Lesage Jacky , Pasqualino Ilson , Benseddiq Noureddine , Bemporad Edoardo
Published: July 2013

The present work aims to evaluate the microstructural mechanisms associated with the initiation of fatigue damage in steels used in the petroleum industry. Microdeformations and residual stresses (macrostresses) are evaluated by X-ray diffraction in real time during alternating bending fatigue tests performed on samples taken from an API 5L X60 grade steel pipe. Microdeformations are evaluated from measurements of the full width at half maximum (FWHM) of the diffraction peak and residual stresses are estimated from the peak displacement. The evolution of microdeformations shows three regular successive stages of changes. The amplitude of variation of each stage is intensified with increasing stress amplitude, while the duration is reduced. A similar evolution is found for residual stresses, whose stages of changes have nearly the same durations as those of microdeformations. Changes in density and distribution of dislocations are observed by transmission electron microscopy combined with the technique of focused ion beam. To understand the role of the initial structure, fatigue tests on annealed samples are performed under the same test conditions. Again, three stages of changes are observed, but with an increase in microdeformations instead of a decrease during the first stage due to the initial state of the dislocation network. The results are very encouraging for the consideration of microstructural changes measured by X-ray diffraction in the development of a future indicator of fatigue damage initiation in API 5L X60 grade steel pipes.
Investigation Into the Effect of Post Weld Heat Treatment on Thermo-Mechanically Controlled Rolled Pipeline Steels
Authors: Slater Simon , Wilkinson Richard
Published: July 2013

Practical options for routing new or diverted pipelines are often limited, which in some cases can lead to the construction of pipelines in potentially seismic or land-slip areas. Designers have advocated the use of heavy wall pipe in these areas; with the potential requirement for girth weld post weld heat treatment (PWHT) to reduce the residual stresses and temper any hard microstructures created during construction welding.

A large proportion of high strength, heavy wall pipe is manufactured using thermo-mechanically controlled processed (TMCP) steel plate. It is generally accepted that these steels are not designed for subsequent PWHT and may suffer some degradation in their mechanical properties when re-heated above critical temperatures. A number of standards, specifications and technical publications acknowledge the influence of PWHT on mechanical properties of TMCP plate, but provide limited guidance on how it will affect the properties. Others refer directly to a detrimental effect, such as BS 4514-1, which states “when PWHT is carried out it may be necessary to verify the properties of the pipe and the welded joints affected by the heat treatment” and EN10208-2 which states “subsequent heating of TMCP material above 580°C may lower the strength”.

The response to PWHT of two TMCP pipeline steels used within the UK gas transmission network has been investigated to confirm if the expected degradation in properties occurs and attempt to quantify the scale of any effect. The pipe material tested was L450MB and L555MB (equivalent grade to API5L X65 and X80), with dimensions 1219 mm × 25.4 mm and 1219 mm × 22.9 mm respectively, manufactured using the UOE process and submerged arc welding. The girth welds were manufactured using a manual metal arc process at the National Grid Pipeline Maintenance Centre in the UK.

The PWHT parameters were selected to represent the top end of the temperature and time ranges available in existing standards and literature, theoretically testing the worst case scenario in terms of any possible deleterious effect.

The project incorporated a detailed test program of the pipe, longitudinal weld and girth weld in both the as-welded and PWHT condition. The paper describes the tests performed and the results obtained.

The mechanical properties of both pipe grades met the minimum requirements of the associated specifications after PWHT. However, a general deleterious effect of PWHT was observed, most significantly for the L555MB material and particularly the longitudinal seam weld. The magnitude of any effect is considered a function of the material chemistry, TMCP parameters, welding consumable and PWHT parameters. PWHT on TMCP pipe materials should be restricted. Where PWHT cannot be avoided, testing should be performed on the specific material to clearly define the magnitude of any deterioration in properties at the proposed PWHT temperature and thermal cycle.
The Impact of Risk in Horizontal Directional Drilling
Authors: Osbak Manley , Bayat Alireza , Murray Carrie
Published: July 2013

The risks, associated with horizontal directional drilling (HDD) can have a significant impact on project schedule and cost. Contractors, engineers and owners are generally aware of the potential impact of this risk, but the awareness is largely qualitative in nature, and is thereby limiting for pointed decision making and the development of measured risk mitigation. Without quantitative information, industry stakeholders are without the means to evaluate risk strategies and identify appropriate risk mitigation measures in a manner that adequately develops and supports the business case for risk mitigation. As a result, the industry often has little choice other than to resort to accepting the risk and hoping for the best or transferring the risk using contractual methods. In order to move to a position of active assessment and mitigation, the industry needs quantitative information about the overall impact of risk as well as a comprehensive enumeration of risk events, the probability of occurrence and the impact of individual events. This paper looks at the general impact of risk as has occurred on 100 medium and large HDD projects. The general impact, in terms of schedule (and by extension, cost), serves to illuminate the need for structured risk mitigation. The paper also lists the risk events that have occurred on these 100 projects, as well as the frequency of occurrence, the average schedule impact and the Risk Index of each event type.
A Wayside System for In-Situ Measurement of Rail Neutral Temperature by Nonlinear Ultrasonic Guided Waves
Authors: Nucera Claudio , Phillips Robert , Lanza di Scalea Francesco , Fateh Mahmood , Carr Gary
Published: July 2013

The University of California at San Diego (UCSD), under a Federal Railroad Administration (FRA) Office of Research and Development (R&D) grant, is conducting research to develop a system for in-situ measurement of the rail Neutral Temperature in Continuous-Welded Rail (CWR). It is known that CWR can break in cold weather and can buckle in hot weather. Currently, there is a need for the railroads to know the current state of thermal stress in the rail, or the rail Neutral Temperature (rail temperature with zero thermal stress), to properly schedule slow-order mandates and prevent derailments.

UCSD has developed a prototype for wayside rail Neutral Temperature measurement that is based on non-linear ultrasonic guided waves. Numerical models were first developed to identify proper guided wave modes and frequencies for maximum sensitivity to the thermal stresses in the rail web, with little influence of the rail head and rail foot. Experiments conducted at the Large-scale Rail NT Test-bed indicated a rail Neutral Temperature measurement accuracy of a few degrees. Field tests are planned at the Transportation Technology Center (TTC) in Pueblo, CO in June 2012 in collaboration with the Burlington Northern Santa Fe (BNSF) Railway.
Development of Analytical Models for Railroad Tank Car Impact and Puncture Behaviors
Authors: Kirkpatrick Steven W. , Munaretto Joseph M. , Phan Virginia , MacNeill Robert A.
Published: July 2013

There has been significant research in recent years to analyze and improve the impact behavior and puncture resistance of railroad tank cars. Much of this research has been performed using detailed nonlinear finite element analyses supported by full scale impact testing. This use of detailed simulation methodologies has significantly improved our understanding of the tank impact behaviors and puncture safety. However, the performance of the detailed analyses or full scale testing can require significant computer or financial resources to evaluate a wide range of impact scenarios.

This paper describes the development of analytical models that can predict the impact and puncture behavior of a pressurized railroad tank car. The methodology applied is to first develop a model that can predict the force-deflection behavior obtained from a general impact at any point on the tank. Separately, a characteristic puncture force is determined as a function of the tank geometry, impactor geometry, and impact conditions. Combined, these models can be applied to predict the impact and puncture behavior of the tank.
Measurement of Residual Stress in Railway Wheels With Vertical Split Rim Failures
Authors: DeWald Adrian T. , Cummings Scott , Punwani John
Published: July 2013

Residual stresses are known to significantly impact the initiation and growth of cracks in metallic components such as railway wheels. Tensile residual stresses are of particular concern due to their ability to non-conservatively affect performance. Vertical split rim (VSR) is an important failure mode for railway wheels. Vertical split rim, like any crack growth failure mode, is significantly influenced by residual stress (e.g., mean or steady stress effects). The crack face of a typical VSR wheel shows signs of low-cycle fatigue. Recently, residual stress measurements were performed on a set of Class C railway wheels. This study looked at the difference in axial residual stress for wheels in three primary conditions: new (as manufactured), service-worn, and wheels that failed through VSR. Residual stresses were significantly larger in the service-worn condition and for wheels that had failed due to VSR relative to the new condition. There is a small difference in the axial residual stress profiles of wheels that failed due to VSR compared to other service-worn wheels. It is unclear, however, if the difference is significant based on a limited population of data. This paper provides a description of the methods used to quantify residual stress in the Class C railway wheels and presents important results from the study.
Emergency Response Training for Locomotive Accidents
Authors: Durrani Samiullah K. , Gertler Judith B. , Punwani S. K. (John)
Published: July 2013

Proper training of emergency responders is essential to safely and effectively respond to a train accident. While there are several existing programs that address training with respect to passenger trains and hazardous materials, training focused on rescuing entrapped crew members from the locomotive cab is lacking. To address this need, the Federal Railroad Administration is sponsoring QinetiQ North America to develop a multi-modal training program to better prepare firefighters to respond to locomotive-involved accidents. The training emphasis is on freight locomotive crew rescue and encompasses three main topics: 1. locate the scene of the incident, 2. access the interior of the cab to rescue personnel, and 3. maintain scene safety. One of the challenges involved in developing this program is the deficiency of knowledge with respect to the tools and techniques that should be utilized in locomotive rescue operations. For this, QNA conducted structural analysis of locomotive cabs and experiments with rescue tools on locomotives. The experiments involved fire rescue personnel and rescue tool manufacturers. Tools ranging from a standard Halligan bar to specialized tools such as hydraulic cutters were tested for effectiveness, speed, and safety. This paper discusses the experimental methodology and lessons learned.
Bearing Condition Monitoring Using Wireless Technology to Reduce the Risk of Bearing Failure
Authors: Wilson Brent M. , Martin Andrew
Published: July 2013

With the need for rail systems to provide long distance and highly reliable operations, problems that could arise should be quickly detected and addressed such that they do not become major issues. If undetected, sudden component faults can result in costly and difficult repair scenarios, and in the worst case, derailments, which can be catastrophic if they occur in populated areas. One such problem, Bearing Burn-off, can result in significant damage to the cars as well as to the rail infrastructure, often before the symptoms can be detected by rail crews and in most situations by wayside mounted infrastructure. A system developed by IONX for railroad operations is designed to monitor rail car bearings to detect potential burn-off conditions before they arise and before they become destructive. This system is comprised of a Central Monitoring Unit (CMU) and Wireless Sensor Nodes (WSNs) which continuously monitor bearing temperatures as well as the current ambient temperature. The application of various algorithms not only conducts trend analysis to anticipate burn-off events, but also reports events at predetermined temperature limits to provide early warning and immediately actionable feedback to locomotive engineers. With these alerts, the driver or train controller can then decide on the appropriate action to be taken and destructive consequences can be avoided saving operational and infrastructure costs. For this pilot study, a total of ten freight cars and fifteen locomotives were equipped, operated, and monitored for an initial three month period. This paper presents preliminary operational results for these tests demonstrating the benefits of predictive condition monitoring systems in real-world applications.
From nanoscience to solutions in electrochemical energy storage
Authors: Rubloff Gary W. , Kozen Alexander C. , Bok Lee Sang
Published: July 2013

Electrical energy storage is a challenging and pivotal piece of the global energy challenge—the “currency” of the energy economy. The opportunity that nanostructures present for advances in storage, recognized two decades ago, has been substantially bolstered by profound advances in nanoscale science and technology, so that a next generation energy storage technology is in sight. The authors present a perspective on the science issues and technology challenges accompanying this vision, focused primarily on the issues as exemplified by lithium ion batteries and made amenable to science through precision heterogeneous nanostructures. The authors address the synthesis and characterization of heterogeneous nanostructures, architectural designs, and recent results, as well as the scientific and technological challenges of integrating dense arrays of nanostructures for a viable technology.
Vacuum frequency mixer with a field emitter array
Authors: Gotoh Yasuhito , Yasutomo Yoshiki , Tsuji Hiroshi
Published: July 2013

A fundamental study on the development of a frequency mixer with a field emitter array was conducted. A grid to control the electron beam was introduced to the vacuum triode, which consisted of a field emitter array and an external collector. The transconductance of the field emitter array was 1.3 μS. It was found that the collector current varied linearly with the grid voltage, and the rate of the variation was estimated to be 0.9 μS. It was suggested that the fabricated tetrode would work as a frequency mixer. A preliminary experiment on the mixing of signals with frequencies of 10 and 15 kHz was performed, and the generation of signals with the sum and difference frequencies was confirmed. The possible operating frequency of the field emitter array-based vacuum frequency mixer will be 1 MHz or higher, using a larger field emitter array that can be operated at higher currents.
Holographic Vortex Liquids and Superfluid Turbulence
Authors: Chesler Paul M. , Liu Hong , Adams Allan
Published: July 2013

Holographic Turbulence

Turbulence in a superfluid presents an even more challenging theoretical problem than classical turbulence.

Chesler
et al.

(p.
368
) studied simulated superfluid turbulence using holographic duality. The direction of the energy flow in a two-dimensional superfluid was opposite to that in classical fluids—the energy injected at long length scales dissipated at short length scales through the vortices that form in a turbulent superfluid.
Nuclear PTEN Controls DNA Repair and Sensitivity to Genotoxic Stress
Authors: Bassi C. , Ho J. , Srikumar T. , Dowling R. J. O. , Gorrini C. , Miller S. J. , Mak T. W. , Neel B. G. , Raught B. , Stambolic V.
Published: July 2013

PTEN Variations

The product of the tumor suppressor gene
phosphate and tensin homolog on chromosome ten
(
PTEN)
is a lipid and protein phosphatase that regulates important cellular processes, including growth, survival, and metabolism (see the Perspective by

Leslie and Brunton

). Though PTEN is best known for effects on the phosphatidylnositol 3-kinase (PI3K) signaling pathway, the PTEN protein is also found in the nucleus.

Bassi
et al.

(p.
395
) found that PTEN's presence in the nucleus was regulated in response to covalent modification of the protein by SUMOylation and phosphorylation. Cells lacking nuclear PTEN showed increased sensitivity to DNA damage and underwent cell death if the PI3K pathway was also inhibited.

Hopkins
et al.

(p.
399
, published online 6 June) discovered an alternative translation start site in human PTEN messenger RNA that allowed expression of a protein, PTEN-Long, with about 170 extra amino acids. The unusual enzyme was released from cells and then taken up into other cells. In a mouse tumor model, uptake of the enzyme inhibited the PI3K pathway and inhibited tumor growth.
Response to Comment on “An Update of Wallace’s Zoogeographic Regions of the World”
Authors: Holt Ben G. , Lessard Jean-Philippe , Borregaard Michael K. , Fritz Susanne A. , Araújo Miguel B. , Dimitrov Dimitar , Fabre Pierre-Henri , Graham Catherine H. , Graves Gary R. , Jønsson Knud A. , Nogués-Bravo David , Wang Zhiheng , Whittaker Robert J. , Fjeldså Jon , Rahbek Carsten
Published: July 2013

Kreft and Jetz’s critique of our recent update of Wallace’s zoogeographical regions disregards the extensive sensitivity analyses we undertook, which demonstrate the robustness of our results to the choice of phylogenetic data and clustering algorithm. Their suggested distinction between “transition zones” and biogeographic regions is worthy of further investigation but is thus far unsubstantiated.
Fish Gold Rush
Billion-Dollar Fish: The Untold Story of Alaska Pollock.
Kevin M. Bailey. University of Chicago Press, Chicago, 2013. 302 pp. $25, £17.50. ISBN 9780226022345.
Authors: Lester Elizabeth
Published: July 2013

Bailey provides a biologist's perspective on the rise of the world's most lucrative food fishery and its uncertain future.
At an Impasse, U.S. Particle Physicists Gather by the River to Plan and Dream
Authors: Cho Adrian
Published: July 2013

As particle physicists in Europe and Japan rack up major discoveries such as the Higgs boson, their counterparts in the United States are about to meet in Minneapolis-St. Paul, Minnesota, to explore options for reviving their own lagging research program.
An Invisible Hand Behind Plan to Realign U.S. Science Education
Authors: Mervis Jeffrey
Published: July 2013

Meet the master bureaucrat behind President Obama's controversial proposal to reshuffle the federal government's $3-billion-a-year investment in STEM education.
NIH Teaching Units, Cherished in Schools, May Be Shredded
Authors: Mervis Jeffrey
Published: July 2013

The science education office at the National Institutes of Health may be forced to dump 180 tons of supplemental lessons on a range of health science issues if it loses its funding under a proposed reorganization of federal STEM education programs.
Meningococcal Polysaccharide A
O
-Acetylation Levels Do Not Impact the Immunogenicity of the Quadrivalent Meningococcal Tetanus Toxoid Conjugate Vaccine: Results from a Randomized, Controlled Phase III Study of Healthy Adults Aged 18 to 25 Years
Authors: Lupisan Socorro , Limkittikul Kriengsak , Sosa Nestor , Chanthavanich Pornthep , Bianco Véronique , Baine Yaela , Van der Wielen Marie , Miller Jacqueline M.
Published: July 2013

In this study, we compared the immunogenicities of two lots of meningococcal ACWY-tetanus toxoid conjugate vaccine (MenACWY-TT) that differed in serogroup A polysaccharide (PS)
O
-acetylation levels and evaluated their immunogenicities and safety in comparison to a licensed ACWY polysaccharide vaccine (Men-PS). In this phase III, partially blinded, controlled study, 1,170 healthy subjects aged 18 to 25 years were randomized (1:1:1) to receive one dose of MenACWY-TT lot A (ACWY-A) (68%
O
-acetylation), MenACWY-TT lot B (ACWY-B) (92%
O
-acetylation), or Men-PS (82%
O
-acetylation). Immunogenicity was evaluated in terms of serum bactericidal activity using rabbit complement (i.e., rabbit serum bactericidal activity [rSBA]). Solicited symptoms, unsolicited adverse events (AEs), and serious AEs (SAEs) were recorded. The immunogenicities, in terms of rSBA geometric mean titers, were comparable for both lots of MenACWY-TT. The vaccine response rates across the serogroups were 79.1 to 97.0% in the two ACWY groups and 73.7 to 94.1% in the Men-PS group. All subjects achieved rSBA titers of ≥1:8 for all serogroups. All subjects in the two ACWY groups and 99.5 to 100% in the Men-PS group achieved rSBA titers of ≥1:128. Pain was the most common solicited local symptom and was reported more frequently in the ACWY group (53.9 to 54.7%) than in the Men-PS group (36.8%). The most common solicited general symptoms were fatigue and headache, which were reported by 28.6 to 30.3% and 26.9 to 31.0% of subjects, respectively. Two subjects reported SAEs; one SAE was considered to be related to vaccination (blighted ovum; ACWY-B group). The level of serogroup A PS
O
-acetylation did not affect vaccine immunogenicity. MenACWY-TT (lot A) was not inferior to Men-PS in terms of vaccine response and was well tolerated.
Virulence, Transmission, and Heterologous Protection of Four Isolates of Haemophilus parasuis
Authors: Brockmeier Susan L. , Loving Crystal L. , Mullins Michael A. , Register Karen B. , Nicholson Tracy L. , Wiseman Barry S. , Baker Rodney B. , Kehrli Marcus E.
Published: July 2013

Haemophilus parasuiscauses Glässer's disease, a syndrome of polyserositis, meningitis, and arthritis in swine. Previous studies withH. parasuishave revealed virulence disparity among isolates and inconsistent heterologous protection. In this study, virulence, direct transmission, and heterologous protection of 4 isolates ofH. parasuis(SW114, 12939, MN-H, and 29755) were evaluated using a highly susceptible pig model. In an initial experiment, isolates 12939, MN-H, and 29755 caused Glässer's disease, while strain SW114 failed to cause any clinical signs of disease. One pig from each group challenged with MN-H or 29755 failed to develop clinical disease but was able to transmitH. parasuisto noninfected pigs, which subsequently developed Glässer's disease. Pigs colonized with SW114, 29755, or MN-H that were free of clinical disease were protected from a subsequent challenge with isolate 12939. In a following experiment, pigs vaccinated with strain SW114 given as either a bacterin intramuscularly or a live intranasal vaccine were protected from subsequent challenge with isolate 12939; however, some pigs given live SW114 developed arthritis. Overall these studies demonstrated that pigs infected with virulent isolates ofH. parasuiscan remain healthy and serve as reservoirs for transmission to naive pigs and that heterologous protection amongH. parasuisisolates is possible. In addition, further attenuation of strain SW114 is necessary if it is to be used as a live vaccine.