bluuebunny/crossref_metadata_2025 huggingface dataset:
Initiation of Stress Corrosion Cracking on X-65 Linepipe Steels in Near-Neutral pH Environment
Authors: Elboujdaini M. , Wang Y.-Z. , Revie R. W.
Published: October 2016

Initiation and early growth of stress-corrosion cracking of X-65 linepipe steel in near-neutral pH environment were studied in NS-4 solution saturated with N2/5%CO2. The occurrence of SCC is discussed in terms of:

1. Generation of an environment that causes cracks to initiate;

2. Initiation and early growth of cracks; and

3. Effect of the mechanical loading spectrum.

SEM observations of cracks at specimen surfaces showed that stress-corrosion cracks were initiated at bottoms of corrosion pits. Pits that lead to initiation of SCC can develop from surface discontinuities, which can be geometrical, such as surface roughness, or metallurgical, such as inclusions, second phase particles, etc. The formation of large cracks resulting from coalescence of micro-cracks was studied.
CEPA Study on Characterization of Pipeline Pressure Fluctuations in Terms Relevant to Stress Corrosion Cracking
Authors: Sutherby Robert , Jack Tom , Van Boven Greg , Wilmott Martyn
Published: October 2016

Neutral-pH stress corrosion cracking (SCC) is a topic of significant interest to pipeline operators in the Canadian Energy Pipeline Association (CEPA). In recent years there has been a shift in laboratory SCC research toward investigating cracking phenomena under more realistic environmental and physical loading conditions. To support this move, CEPA has been active in collecting pressure-time data from its varied membership of liquid and gas pipeline companies. Histories of pressure fluctuations in operating systems have been characterized in terms of loading cycles, R-values (the ratio of minimum to maximum stress) and strain rates. These parameters are relevant to the design of laboratory experiments for the investigation of SCC. An overview of the data is presented for both liquid and gas pipelines in various service applications.
Effect of Surface Scratch Roughness and Orientation on the Development of SCC of Line Pipe Steel in Near Neutral pH Environment
Authors: He Daxiong , Chen Weixing , Luo Jingli , King Fraser , Jack Tom , Krist Kevin
Published: October 2016

This research has focused on the effect of surface roughness and surface scratch orientation on the development of neutral pH SCC on pipeline steels. The susceptibility to neutral pH SCC was assessed in this study using slow strain rate testing on X-65 line pipe steel. The surfaces of the test samples were ground using either #240 or #600 sandpaper to introduce different scratch roughness. Scratches were produced with an orientation parallel, perpendicular and inclined at 45° to the loading direction, respectively. The test samples were exposed to a synthetic neutral pH ground water at both open circuit potential (OCP) and −800 mV (SCE).

It has been found that the reduction in ductility due to a near neutral pH environment was more than 20% larger for the specimens with perpendicular scratches than those with parallel scratches, either at OCP or −800 mV (SCE). Roughness appeared to have little effect on the ductility of the specimen with parallel scratches. However, it has some effect on the sample with perpendicular scratches. For these samples, a finer scratch caused more reduction in ductility than the rougher scratches, particularly under cathodically protected conditions. The reduction in ductility for the specimen with scratches 45° inclined to stress axis was in between those with parallel and perpendicular scratches.

The difference in ductility arising from scratch roughness and orientation was consistent with the observation of the surface conditions after test. For samples with perpendicular and angle scratches, cracks were seen to coincide with scratch lines. For those with parallel scratches, only short cracks developed in a direction approximately 45° to the stress axis. Mechanisms concerning this scratch-facilitated crack formation are discussed.
Hydrate and Wax Prevention in Flowlines by Electrical Heating
Authors: Lervik Jens Kristian , Kulbotten Harald , Klevjer Gunnar , Iversen Øyvind
Published: October 2016

Traditional chemical treatment methods have considerable operation costs and represent a risk to the environment. Since 1987 Norwegian oil companies have been investigating alternative electrical heating methods for prevention of hydrate and wax plugs. A joint industry project ‘Concept Verification – Direct Heating of Oil & Gas Pipelines’ was initiated in 1996 and terminated in October 1999. During this work an electrical heating system was proved to be feasible on several fields in the North Sea. It will be installed on 7 flowlines of 13% Chromium (Crl3) with lengths between 6 km and 16 km. Electrical heating is used to maintain or raise the thermally insulated steel pipe temperature above the critical value for hydrate formation (typically 15–25 °C) or wax formation (typically 20–40°C). A single-phase power supply for the heating system is based on commercial components and connected to the platform power supply. The qualification work for the direct heating system has included full scale testing for single and parallel pipes, end termination at the template, bypass of a template and aspects concerning corrosion control. The rating of the system is dependent on the magnetic and electrical characteristics of the steel material. Such data is not commonly available.

Measurements performed during the qualification program confirm that the magnetic characteristic may vary within a wide range for a specific steel quality and that mechanical stress and heat treatment can effect the magnetic characteristic. The difference in magnetic characteristic of individual Crl3 pipes results in variation of the pipe temperature and problems concerning differential pressure during melting. The problem can be handled by dividing the pipeline into a number of sections, each with a limited variation of the magnetic characteristic, thus keeping the temperature for the whole pipeline within acceptable limits. As a part of the pipe specification both electrical and magnetic characteristic should be available. These data can be determined by measuring arrangements in the production line of the mill. Measures to limit the variation of magnetic characteristic should be discussed.
Pipeline Survey Scheduling Through Structural Reliability Analysis
Authors: Espiner Richard J. , Edwards Alan M. , Francis Andrew
Published: October 2016

In order to reduce the risks associated with the occurrence of free spans, offshore pipelines are subject to external survey on a periodic basis. The true impact of this strategy on safety and reliability is generally unknown.

This paper describes a structural reliability-based assessment that was carried out to investigate the probability of failure of an offshore pipeline due to the presence of free spans and develop a survey strategy that ensures a quantified and acceptable level of reliability.

The probabilities of failure of free spans of varying lengths are evaluated using a structural reliability based approach. Then, the probability of occurrence of free spans as a function of time is evaluated in order to quantify the overall time-dependent reliability of the pipeline. Finally, the influence of the survey frequency is investigated. The outcome of the study is a recommended strategy for future surveys of the pipeline.
Rational Modeling of Ultimate Pipe Strength Under Bending and External Pressure
Authors: Nogueira André C. , Lanan Glenn A.
Published: October 2016

The capacity of pipelines to resist collapse or local buckling under a combination of external pressure and bending moment is a major aspect of offshore pipeline design. The importance of this loading combination increases as oil and gas projects in ultra deep-water, beyond 2,000-m water depths, are becoming reality. The industry is now accepting, and codes are explicitly incorporating, limit state design concepts such as the distinction between load controlled and displacement controlled conditions. Thus, deep-water pipeline installation and limit state design procedures are increasing the need to understand fundamental principles of offshore pipeline performance.

Design codes, such as API 1111 (1999) or DNV (1996, 2000), present equations that quantify pipeline capacities under combined loading in offshore pipelines. However, these equations are based on empirical data fitting, with or without reliability considerations. Palmer (1994) pointed out that “it is surprising to discover that theoretical prediction [of tubular members under combined loading] has lagged behind empirical prediction, and that many of the formula have no real theoretical backup beyond dimensional analysis.”

This paper addresses the ultimate strength of pipelines under combined bending and external pressure, especially for diameter-to-thickness ratios, D/t, less than 40, which are typically used for deep water applications. The model is original and has a rational basis. It includes considerations of ovalization, anisotropy (such as those caused by the UOE pipe fabrication process), load controlled, and displaced controlled conditions. First, plastic analysis is reviewed, then pipe local buckling under pure bending is analyzed and used to develop the strength model. Load controlled and displacement controlled conditions are a natural consequence of the formulation, as well as cross section ovalization. Secondly, external pressure effects are addressed. Model predictions compare very favorably to experimental collapse test results.
Stability Problems for Deep-Water Gas Pipelines: The “Blue Stream” Project
Authors: Kharionovsky V. V.
Published: October 2016

OAO “GAZPROM” in collaboration with SNAM and Saipem have developed the first stage of the “Blue Stream” Project, which when completed will be unique for the world gas industry in terms of its parameters and route conditions. During this feasibility stage of the project the following new Research and development tasks were addressed:

- deep water collapse problems (the depths reach 2150 m), including buckle propagation;

- the problem of pipeline protection against an H2S environment (in the near bottom zone H2S concentration reaches more than 14 mg/1);

- the problem of installing a reliable pipeline having a diameter of 610×31.8 mm at gas pressures of 25 Mpa while taking into account the subsea currents;

- construction problems associated with the specified parameters.

Solving such problems required an elaborate and complex set of design tasks and experiments with materials and construction conditions. Special requirements were developed for the pipes and fittings, external anti-corrosion coatings, and the cathodic protection of the pipeline. New procedural documents were developed for deep water pipelining that included: the calculation for determining the strength and stability of the offshore pipelines; an instruction manual for the onshore section of the pipeline designed to carry a gas pressure of 25 Mpa; the necessary software for thermal and hydraulic calculations for the gas pipeline under extremely high pressures.
High Speed Data Communications and High Speed Leak Detection Models: Impact of Thermodynamic Properties for Heated Crude Oil in Large Diameter, Insulated Pipelines — Application Pacific Pipeline System
Authors: Mecham Travis , Stanley Galen , Pelletier Michael , Liou Jim C. P.
Published: October 2016

Recent advances in SCADA and leak detection system technologies lead to higher scan rates and faster model speeds. As these model speeds increase and the inherent mathematical uncertainties in implicit method solutions are reduced, errors and uncertainties in measurement of the physical properties of the fluids transported by pipeline come to dominate the confidence calculations for computer generated leak alerts in the control center.

The ability to collect more data must be supported by the need for better model data in order to achieve optimal leak detection system performance. This is particularly true when the products transported are non-homogeneous and have strong viscosity-vs-temperature relationships. These are characteristics of crude oils in California’s San Joaquin Valley where significant heating is required to pump these oils in an efficient manner. Proper characterization and correct mathematical expression of these physical properties in leak models has become critical.

This paper presents these new developments in the context of an implementation of this new technology for the Pacific Pipeline System (PPS). PPS is a recently constructed and commissioned 209 km (130-mile), 50.8 cm (20″) diameter, insulated, hot crude oil pipeline between the southern portion of California’s San Joaquin Valley and refineries in the Los Angeles basin. Operational temperatures in this line vary from ambient to 82.2°C (180°F) with pressures ranging from 345 kPa (50 psi) to 11,720 kPa (1700 psi). Due to the unique geometry of the line, facilities along the route include pumping stations, metering stations and numerous “throttle-type” pressure reduction facilities.

On PPS, a high-speed leak detection model is supported by a fiber optic (OC-1) communication backbone with data rate capacities in excess of 50 Megabits Per Second (MPS). Total scan times for the distributed communication system have been reduced to 1/4 second — each facility reports data to the SCADA host four times each second. A corresponding 1/4 second leak detection model cycle leads to selection of Methods of Characteristics segments on the order of 260 meters (850 feet). This resolution, in conjunction with the advanced instrumentation package of PPS, makes detection of very small leaks realizable.

This paper starts with an overview of the system and combines a mix of the theoretical requirements imposed by the mathematical solutions with a practical description of the laboratory procedures and propagated experimental errors. The paper reviews temperature-related errors and uncertainties and their influence on leak detection performance.
Electronic Equipment Provides Pipeline Monitoring and Protection: Applications and Limitations
Authors: Penney Randy , Flesher Hugh
Published: October 2016

Background: Line break controls developed to date have provided the Pipeline Industry with the best protection available with proven and available technologies.

There have been shortcomings in line break control due to various factors including; lack of accurate pressure history at the valve sites creating uncertainty for proper set points and limitations in the flexibility of mechanical systems.

Safety: Providing pipeline safety through a line break detection system is critically important for the protection of people, property, and the environment. Safer procedures are available through continuous pipeline monitoring.

Application of new technology: Increased availability of “smart” pressure sensors offers a greater degree of accuracy and control. Real time communication for data collection and system configuration (operating data, alarm status and settings, valve status) or remote operation (valve closures or line break override) provides increased control over pipeline operations.

Real time information allows continuous monitoring and control. This can be provided through commercially available networks, hence providing economical and reliable methods of communication.

Data acquisition through Windows based software allows the user to accumulate, sort, and analyze the data.

Overview: Industry requires the ability to monitor pipeline pressures and pipeline rate of pressure change.

Industry requires accuracy, reliability, and real time access for controlling valves, while minimizing the occurrences of false valve closures. The pipeline and gas transmission industry is growing, with increasing demands for safe, reliable, and efficient operating systems. New technologies are capable of providing solutions for the Pipeline Industry’s needs.

Solutions: A self-contained electronic system, purpose built for the gas pipeline industry is available. The equipment continuously monitors the pipeline, measures pipeline pressures, and calculates pressure changes so that, in the case of a pipeline failure, a command is sent to the actuator to stroke the valve to the fail safe position. The equipment is accessible locally or remotely via SCADA or telemetry to acquire and analyze pipeline conditions on a real time basis, and control the actuator. The equipment is low power consumption suitable for external line power, or is available with solar panels and rechargeable batteries. The equipment continuously gathers information and provides history for pipeline operators. This allows the optimization of set points, with time delays and averaging, to minimize false trips.

Windows based software enables ease of use.

Owner can set alarm parameters that are protected through password authorization.

Summary: Electronic Linebreak Detection Systems are able to provide the flexibility, reliability and responsiveness necessary to meet the growing safety and efficiency demands of the Pipeline Industry. Current technology provides this capability.
Integrity Monitoring: Not Just Leak Detection
Authors: Hagar Kevin , Young Bruce , Mactaggart Ross
Published: October 2016

There are many uses for a software based, real time leak detection system other than just leak detection. Leak detection systems, based on a real time model, have many uses, including instrument analysis, slack line flow detection, batch, scraper and DRA tracking. Hydraulic profiles, trends and Imbalance Signature Plots provide operational tools to augment SCADA displays. When abnormal imbalance is reported, the operator has tools to pin point the problem. These results can also be made available enterprise-wide for use by higher level processes such as accounting, scheduling, planning, and marketing.
Using Genetic Algorithm and Simplex Method to Stabilize an Oil Treatment Plant Inlet Flow
Authors: Silva Adriano C. , Ohishi Takaaki , Mendes Alexandre S. , França Fernando A. , Delgado Eliana A. R.
Published: October 2016

This paper presents a hybrid approach, composed of a genetic algorithm and a linear programming method, to achieve an efficient pipeline network operation. The pipeline network optimization consists of the determination of pump scheduling over a short-term horizon, usually one or more days ahead. The resulting mathematical problem has a dynamic and combinatorial characteristic, in which a sub-optimal solution was obtained through these two mathematical tools in a short computational time. The approach was applied in a Pipeline Network to a study case based on the Patagonia Argentina, which is comprised of 16 tanks and linked pumps, with 66 kilometers of pipelines, that transport the production of more than 100 wells to a pre-processing plant. The goal was to obtain a constant input flow rate at the plant respecting physical and chemical processes requirements.
Development and Use of Simulation Trainers for Pipeline Controllers
Authors: Scott D. M.
Published: October 2016

Enbridge is in the forefront of development and application of computer simulation based training systems for Pipeline Controllers. Since 1985, the Pipeline Dynamics section of Enbridge Engineering has been building ever more sophisticated models of the 16 pipelines that Enbridge owns and operates. Enbridge has also utilized its staffs expertise to develop simulation trainer applications for clients in other international pipeline companies. Enbridge uses this simulation trainer with a formalized, module based, training course for Pipeline Controllers.

To develop a useful simulation trainer it must be possible to mimic the operational characteristics of a pipeline through use of software, or put otherwise, to build a pipeline in a computer. This type of modeling requires a highly skilled engineer and close cooperation with the most experienced Pipeline Controller and with the SCADA system developers. The simulation software must also allow the application of control logic which is different for each pipeline and it must be tunable so the nuances of each pipeline can be incorporated. Running this type of application requires a high capacity computer and the ability to interface with the pipeline company’s SCADA. In simple applications, it is possible to develop a generic pipeline and thus provide a more economical trainer.

The simulation trainer’s primary application is Pipeline Controller training, however it is Enbridge’s experience that a simulation can also be used to test changes to a SCADA system before they are implemented and to operate a new pipeline before it goes into operation. The information gained from the pipeline operation prior to its construction can benefit the engineering design.

This paper outlines the Enbridge experience with development and use of pipeline simulation trainers. The paper also discusses how the simulation trainer fits with formal training, testing and retraining of Pipeline Controllers, how it has been used for SCADA system testing and for operating a new pipeline before it’s construction. The paper outlines what is required for the development of generic and specific simulations that are interfaced to SCADA, the use of modeling standards in the development, and the process of tuning a model so it ‘looks and feels’ like a real pipeline.
How to Design and Operate Quiet Centrifugal Compressor System
Authors: Motriuk Roman W.
Published: October 2016

Historically, designs of centrifugal compressor systems focused on the aerodynamic and performance aspects. Noise, pulsation, and vibration phenomena were rarely considered. Recent applications of high flow and high power centrifugal compressors require that this approach be changed. Several transmission system failures, in different gas transmission companies, were documented. They included fatigue failures of the compressor components, piping attachments, and, in some instances, pipework shell failures. As a result, numerous investigations were carried out. While the compressors were adequately designed from the aerodynamic performance point of view, they appeared to act as dynamic generators, producing excessive noise, pulsation, and vibration levels even when operated well within their design parameters. It was found that neither the designers nor equipment users had a clear understanding on how to practically analyse and mitigate such dynamic phenomena.

The objective of this study is to briefly explain possible sources of the observed problems in the hope that such explanation might provide a means for preventing or minimising noise and pulsation generation in centrifugal machines. The study is based on the author’s experience in mitigating pulsation/noise and vibration problems mainly in the single stage natural gas centrifugal compressor systems. The study briefly describes differences in operation between vaned and vaneless diffuser compressors. It considers pipework and its influence on the compressor dynamic performance, and addresses some aspects of the compressor design in both aerodynamic and acoustic areas. Furthermore, it gives several practical methods to mitigate high frequency pulsation and vibration problems. Most of the approaches suggested here were implemented in the field and evaluated either by the author or others.
Shop Versus Site Performance Testing of Gas Turbines and Centrifugal Compressors
Authors: Scott John N.
Published: October 2016

Performance guarantees are an integral part of the purchase of turbo-compressor equipment. Traditionally the testing is done at the equipment supplier’s factory in accordance with the appropriate test code. This paper puts forward technical and economic arguments for basing the final acceptance of the equipment on site tests. The equipment considered is in the 5 MW to 30 MW range.

The main emphasis of the paper is on making the site tests conform as closely as possible to the factory tests so that the results are acceptable to the manufacturer. The paper also includes discussions on the differences between shop test and site test procedures and results, comparative costs, site test specifications, instrumentation selection, and data analysis techniques.
Designing Compressor Installations for Reliability
Authors: Greenfield Shelley D. , Howes Brian C. , Robinson Alasdair , Eckert William
Published: October 2016

This paper discusses and illustrates how the application of analytical tools, if properly applied, during the design process ensures a design that is both reliable and economic. Emphasis is on the dynamic behavior of centrifugal and reciprocating compressors. Illustrations deal with both types of compressors.

The key requirement is that pulsations, vibration levels and dynamic stresses must be low enough, that there is minimal impact on performance or reliability, while maintaining an economical design. To achieve this result, it is necessary to understand and control forcing functions, natural frequencies, mode shapes and dynamic stiffnesses. These considerations apply to rotor dynamics, piping vibration, torsional vibration, skid and foundation vibration. In addition, similar considerations apply to gas pulsations, where the interaction of the piping geometry with pressure pulsations, (arising from the uneven flow of gas through the suction and discharge nozzles), can produce significant forces and stresses for both reciprocating and centrifugal compressors, as well as degradation of performance.

Computer modeling can be used to avoid problems that reduce reliability, degrade performance and increase maintenance. Considerations for determining the appropriate level of analysis are outlined. The probability and cost of events in the absence of suitable design are discussed. The cost of these events is compared to relevant design costs.

The practical implications are illustrated with three cases where adequate design modeling and optimization was not done. One case involves a lateral critical and a structural resonance in a centrifugal compressor installation. The second involves a piping failure in a reciprocating compressor installation. The third involves a torsional failure in a reciprocating compressor installation.
Chemical vapor deposition of MnxNy films from bis(2,2,6,6-tetramethylpiperidido)manganese(II) and ammonia
Authors: Mohimi Elham , Trinh Brian B. , Babar Shaista , Girolami Gregory S. , Abelson John R.
Published: October 2016

Thin films of manganese nitride MnxNy are grown by chemical vapor deposition (CVD) using the new precursor bis(2,2,6,6-tetramethylpiperidido)manganese(II), Mn(tmp)2 = Mn(NC9H18)2, with ammonia as a coreactant. This precursor can be prepared in high synthetic yield and has good thermal stability at room temperature; it is one example of a new class of precursors that have the potential to deposit late transition metal nitrides. Under low-pressure CVD conditions, the precursor reacts with ammonia to afford MnxNy thin films in the temperature range of 50–350 °C. The stoichiometric ratio x/y is 2.3–2.5 for all growth conditions used, with oxygen and carbon impurities less than 7 at.% and 1 at.% in the bulk, respectively, as analyzed by x-ray photoelectron spectroscopy. The MnxNy films are x-ray amorphous and are characterized by low root-mean-square surface roughness, 0.4–0.7 nm. Film thickness profiles on trench substrates indicate that growth contains species of both high and low sticking probabilities. The proposed mechanism of film growth is a combination of gas phase and surface transamination between the precursor and ammonia to afford reactive intermediates responsible for film growth.
Laryngeal muscular control of vocal fold posturing: Numerical modeling and experimental validation
Authors: Yin Jun , Zhang Zhaoyan
Published: October 2016

A three-dimensional continuum model of vocal fold posturing was developed to investigate laryngeal muscular control of vocal fold geometry, stiffness, and tension, which are difficult to measure in live humans or in vivo models. This model was able to qualitatively reproduce in vivo experimental observations of laryngeal control of vocal fold posturing, despite the many simplifications which are necessary due to the lack of accurate data of laryngeal geometry and material properties. The results present a first comprehensive study of the co-variations between glottal width, vocal fold length, stiffness, tension at different conditions of individual, and combined laryngeal muscle activation.
Stimulus-directed attention attenuates lexically-guided perceptual learning
Authors: McAuliffe Michael , Babel Molly
Published: October 2016

Studies on perceptual learning are motivated by phonetic variation that listeners encounter across speakers, items, and context. In this study, the authors investigate what control the listener has over the perceptual learning of ambiguous /s/ pronunciations through inducing changes in their attentional set. Listeners' attention is manipulated during a lexical decision exposure task such that their attention is directed at the word-level for comprehension-oriented listening or toward the signal for perception-oriented listening. In a categorization task with novel words, listeners in the condition that maximally biased listeners toward comprehension-oriented attentional sets showed the most perceptual learning. Focus on higher levels of linguistic meaning facilitated generalization to new words. These results suggest that the way in which listeners attend to the speech stream affects how linguistic categories are updated, providing insight into the qualitative differences in perceptual learning between the psychophysics and language-focused literatures.
Ultrasonic method to characterize shear wave propagation in micellar fluids
Authors: Amador Carolina , Otilio Bruno L. , Kinnick Randall R. , Urban Matthew W.
Published: October 2016

Viscoelastic micellar fluid characteristics have been measured with mechanically generated shear waves and showed good agreement to shear oscillatory methods. In this paper, shear waves in wormlike micellar fluids using ultrasound were successfully generated and detected. Micellar fluids of different concentrations (100, 200, 300, and 400 mM) were studied with ultrasound-based and conventional rheology methods. The measured micellar fluid complex modulus from oscillatory shear tests between 0.001 and 15.91 Hz was characterized with an extended Maxwell fluid model. The elastic and viscous parameters found using rheological testing were used to estimate shear wave phase velocity over a frequency range from 100 to 500 Hz, and compared to shear wave velocity measured with ultrasound-based methods with a mean absolute error 0.02 m/s. The shear wave frequency content was studied and an increase in shear wave center frequency was found as a function of micellar fluid concentration. Moreover, the bias found in the shear wave group velocity with respect to rheological measurement is attributed to the micellar fluid viscous component. Finally, the shear wave phase velocity evaluated at the center frequency agreed well with the rheological measurements.
Laser beam shaping for enhanced Zero-Group Velocity Lamb modes generation
Authors: Bruno François , Laurent Jérôme , Jehanno Paul , Royer Daniel , Prada Claire
Published: October 2016

Optimization of Lamb modes induced by laser can be achieved by adjusting the spatial source distribution to the mode wavelength (λ). The excitability of Zero-Group Velocity (ZGV) resonances in isotropic plates is investigated both theoretically and experimentally for axially symmetric sources. Optimal parameters and amplitude gains are derived analytically for spot and annular sources of either Gaussian or rectangular energy profiles. For a Gaussian spot source, the optimal radius is found to be λZGV/π. Annular sources increase the amplitude by at least a factor of 3 compared to the optimal Gaussian source. Rectangular energy profiles provide higher gain than Gaussian ones. These predictions are confirmed by semi-analytical simulation of the thermoelastic generation of Lamb waves, including the effect of material attenuation. Experimentally, Gaussian ring sources of controlled width and radius are produced with an axicon-lens system. Measured optimal geometric parameters obtained for Gaussian and annular beams are in good agreement with theoretical predictions. A ZGV resonance amplification factor of 2.1 is obtained with the Gaussian ring. Such source should facilitate the inspection of highly attenuating plates made of low ablation threshold materials like composites.
Evaluation of a method for enhancing interaural level differences at low frequencies
Authors: Moore Brian C. J. , Kolarik Andrew , Stone Michael A. , Lee Young-Woo
Published: October 2016

A method (called binaural enhancement) for enhancing interaural level differences at low frequencies, based on estimates of interaural time differences, was developed and evaluated. Five conditions were compared, all using simulated hearing-aid processing: (1) Linear amplification with frequency-response shaping; (2) binaural enhancement combined with linear amplification and frequency-response shaping; (3) slow-acting four-channel amplitude compression with independent compression at the two ears (AGC4CH); (4) binaural enhancement combined with four-channel compression (BE-AGC4CH); and (5) four-channel compression but with the compression gains synchronized across ears. Ten hearing-impaired listeners were tested, and gains and compression ratios for each listener were set to match targets prescribed by the CAM2 fitting method. Stimuli were presented via headphones, using virtualization methods to simulate listening in a moderately reverberant room. The intelligibility of speech at ±60° azimuth in the presence of competing speech on the opposite side of the head at ±60° azimuth was not affected by the binaural enhancement processing. Sound localization was significantly better for condition BE-AGC4CH than for condition AGC4CH for a sentence, but not for broadband noise, lowpass noise, or lowpass amplitude-modulated noise. The results suggest that the binaural enhancement processing can improve localization for sounds with distinct envelope fluctuations.
Coconut Water Does Not Improve Markers of Hydration During Sub-maximal Exercise and Performance in a Subsequent Time Trial Compared with Water Alone
Authors: Peart Daniel J. , Hensby Andy , Shaw Matthew P.
Published: October 2016

The purpose of this study was to compare markers of hydration during submaximal exercise and subsequent time trial performance when consuming water (PW) or coconut water (CW). There was also a secondary aim to assess the palatability of CW during exercise and voluntary intake during intense exercise. 10 males (age 27.9 ± 4.9 years, body mass 78.1 ± 10.1kg, average max minute power 300.2 ± 28.2W) completed 60-min of submaximal cycling followed by a 10-km time trial on two occasions. During these trials participants consumed either PW or CW in a randomized manner, drinking a 250 ml of the assigned drink between 10–15 min, 25–30 min and 40–45 min, and then drinking ad libitum from 55-min until the end of the time trial. Body mass and urine osmolality were recorded preexercise and then after 30-min, 60-min, and post time trial. Blood glucose, lactate, heart rate, rate of perceived exertion (RPE; 6–20) and ratings of thirst, sweetness, nausea, fullness and stomach upset (1 =very low/none, 5= very high) were recorded during each drink period. CW did not significantly improve time trial performance compared with PW (971.4 ± 50.5 and 966.6 ± 44.8 s respectively; p = .698) and there was also no significant differences between trials for any of the physiological variables measured. However there were subjective differences between the beverages for taste, resulting in a significantly reduced volume of voluntary intake in the CW trial (115 ± 95.41 ml and 208.7 ± 86.22 ml; p < .001).
Depleting dietary valine permits nonmyeloablative mouse hematopoietic stem cell transplantation
Authors: Taya Yuki , Ota Yasunori , Wilkinson Adam C. , Kanazawa Ayano , Watarai Hiroshi , Kasai Masataka , Nakauchi Hiromitsu , Yamazaki Satoshi
Published: October 2016

Hematopoietic stem cell maintenance requires the amino acid valine.
A coherent Ising machine for 2000-node optimization problems
Authors: Inagaki Takahiro , Haribara Yoshitaka , Igarashi Koji , Sonobe Tomohiro , Tamate Shuhei , Honjo Toshimori , Marandi Alireza , McMahon Peter L. , Umeki Takeshi , Enbutsu Koji , Tadanaga Osamu , Takenouchi Hirokazu , Aihara Kazuyuki , Kawarabayashi Ken-ichi , Inoue Kyo , Utsunomiya Shoko , Takesue Hiroki
Published: October 2016

Taking the pulse of optimization

Finding the optimum solution of multiparameter or multifunctional problems is important across many disciplines, but it can be computationally intensive. Many such problems defined as computationally difficult can be mathematically mapped onto the so-called Ising problem, which looks at finding the minimum energy configuration for an array of coupled spins. Inagaki
et al.
and McMahon
et al.
show that an optical processing approach based on a network of coupled optical pulses in a ring fiber can be used to model and optimize large-scale Ising systems. Such a scalable architecture could help to optimize solutions to a wide range of complex problems.

Science
, this issue pp.
603
and
614
Draft Genome Sequence of Escherichia coli 26R 793, a Plasmid-Free Recipient Strain Commonly Used in Conjugation Assays
Authors: Wang Juan , Hurley Daniel , McGrath Kathleen , Bai Li , Hächler Herbert , Stephan Roger , Fanning Séamus
Published: October 2016

Here, we report the draft genome sequence of the lactose-negative, rifampin-resistant,
Escherichia coli
strain 26R 793. This isolate has been widely used in conjugation experiments as a general recipient strain.
Draft Genome Sequence of Leifsonia xyli subsp.
xyli
Strain gdw1
Authors: Wang Jihua , Wang Li , Cao Gan , Zhang Muqing , Guo Ying
Published: October 2016

Here, we report the draft genome sequence of
Leifsonia xyli
subsp.
xyli
strain gdw1, isolated from the stem of Badila sugarcane located at the Guangdong Key Laboratory for Crops Genetic Improvement (Guanzhou, China), that causes ratoon stunting disease of sugarcane. The
de novo
genome of
Leifsonia xyli
subsp.
xyli
was assembled with 48 scaffolds and a G+C content of 67.68%, and contained 2.6 Mb bp and 2,838 coding sequences.
Draft Genome Sequences of Two
Geobacillus
Species Strains, Isolated from Oil Wells and Surface Soil above Oil Pools
Authors: Kaunietis Arnoldas , de Jong Anne , Pranckutė Raminta , Buivydas Andrius , Kuipers Oscar P.
Published: October 2016

Here, we present the draft genome sequences of two
Geobacillus
species strains isolated from oil wells and surface soil above oil pools in Lithuania.
Genome Sequence of Carbon Dioxide-Sequestering
Serratia
sp. Strain ISTD04 Isolated from Marble Mining Rocks
Authors: Kumar Manish , Gazara Rajesh Kumar , Verma Sandhya , Kumar Madan , Verma Praveen Kumar , Thakur Indu Shekhar
Published: October 2016

The
Serratia
sp. strain ISTD04 has been identified as a carbon dioxide (CO
2
)-sequestering bacterium isolated from marble mining rocks in the Umra area, Rajasthan, India. This strain grows chemolithotrophically on media that contain sodium bicarbonate (NaHCO
3
) as the sole carbon source. Here, we report the genome sequence of 5.07 Mb
Serratia
sp. ISTD04.
Draft Genome Sequence of Rhodococcus erythropolis NSX2, an Actinobacterium Isolated from a Cadmium-Contaminated Environment
Authors: Egidi Eleonora , Wood Jennifer L. , Fox Edward M. , Liu Wuxing , Franks Ashley E.
Published: October 2016

Rhodococcus erythropolis
NSX2 is a rhizobacterium isolated from a heavy metal–contaminated environment. The 6.2-Mb annotated genome sequence shows that this strain harbors genes associated with heavy-metal resistance and xenobiotics degradation.
Draft Genome Sequences of Chryseobacterium artocarpi UTM-3
T
and Chryseobacterium contaminans C26
T
, Isolated from Rhizospheres, and Chryseobacterium arthrosphaerae CC-VM-7
T
, Isolated from the Feces of a Pill Millipede
Authors: Jeong Jin-Ju , Park Byeonghyeok , Oh Ji Yeon , Mannaa Mohamed , Kim Yoo Jun , Hong Jeum Kyu , Choi In-Geol , Kim Ki Deok
Published: October 2016

Species of the genus
Chryseobacterium
belonging to the family
Flavobacteriaceae
are nonmotile, yellow-pigmented, and rod-shaped bacteria, some of which were frequently isolated from soil or plant-related materials. Here, we present draft genome sequences of three type strains of
Chryseobacterium
, which contain genes related to plant growth promotion, colonization, or stress adaptation.
Complete Genome Sequence of Human Norovirus Strain GII.P7-GII.6 Detected in a Patient in the United States in 2014
Authors: Yang Zhihui , Vinjé Jan , Elkins Christopher A. , Kulka Michael
Published: October 2016

Homologous recombination is one of the driving forces contributing to the genetic variation of human norovirus, which is an important cause of sporadic and epidemic acute gastroenteritis globally. We report the near-complete genome of the novel recombinant norovirus strain GII.P7-GII.6, detected in an adult with norovirus gastroenteritis in the United States.
Mechanical amorphization, flash heating, and frictional melting: Dramatic changes to fault surfaces during the first millisecond of earthquake slip
Authors: Hayward Kathryn S. , Cox Stephen F. , Fitz Gerald John D. , Slagmolen Bram J.J. , Shaddock Daniel A. , Forsyth Perry W.F. , Salmon Michelle L. , Hawkins Rhys P.
Published: October 2016

The evolution of fault strength and behavior during the initial stages of slip plays an important role in driving the onset of instability and fault weakening. Using small-displacement triaxial experiments on quartz sandstone, this study highlights the rapid onset of microstructural change on fault interfaces and identifies new evidence for an evolution in physical processes with increasing slip and velocity. Pre-ground fault surfaces have been slipped over a range of velocities (0.36 µm s–1 to 18 cm s–1) and at normal stresses comparable to upper- to mid-crustal conditions (92–287 MPa). Microstructural analysis of the fault interfaces reveals the formation of amorphous material at displacements <170 µm and slip durations < 1 ms. Mechanical and microstructural observations have been combined with numerical modeling to present the first documented examples of a transition from mechanical amorphization to flash heating, then frictional melting, with changes in slip conditions. The sequence of processes activated during the initial stages of fault movement may provide new insights into factors that influence the onset of slip in the seismogenic crust.
Total recovery of optic nerve sheath meningioma
Authors: Charpentier Pierre , Mouriaux Frederic
Published: October 2016

We reported the case of a 43-year-old woman with a rapid progressive visual loss. The diagnosis of primary optic nerve sheath meningioma was made thanks to atypia evolution, clinical and radiological findings. The patient was treated with an intensity-modulated radiotherapy of 50.4 Gy in 28 fractions 2 months after the diagnosis. Visual acuity and visual field were completely recovered after 2 years of follow-up. No late side effects of irradiation were recorded.
Rare case of type I hypersensitivity reaction to sodium hypochlorite solution in a healthcare setting
Authors: Chia Shi Zhe Gabriel , Green Andrew , Fong Yuke Tien , Lee Haur Yueh , Ho Sweet Far
Published: October 2016

Sodium hypochlorite is a clear yellowish solution with a characteristic odour of chlorine and is commonly used as a disinfectant and a bleaching agent. It is used in various healthcare settings for its fast-acting and broad-spectrum antimicrobial activity. It is a known irritant and there are some reports that it can also cause allergic contact dermatitis of type IV hypersensitivity. We report a case of work-related type I hypersensitivity to sodium hypochlorite, presenting with recurrent urticarial rash and a positive prick test reaction to this chemical. He was subsequently excused from further exposure with no further recurrences of the urticarial rash. To the best of our knowledge, this is the first such reported case due to work in the healthcare setting.
German translation and content validation of the OSTRC Questionnaire on overuse injuries and health problems
Authors: Hirschmüller A , Steffen K , Fassbender K , Clarsen B , Leonhard R , Konstantinidis L , Südkamp N P , Kubosch E J
Published: October 2016

Objective

The aim of this study was to translate, culturally adapt and validate the Oslo Sports Trauma Research Centre (OSTRC) Questionnaire on Health Problems into the German context.

Methods

A slightly modified back-translation method was used to translate the questionnaire. Validation was done in 24 high-level Paralympic athletes followed over 20 consecutive weeks.

Results

The translated version of the questionnaire showed a very high internal consistency and good test–retest reliability (Cronbach's α 0.92, intraclass correlation coefficient 0.91). Additionally, we observed high acceptance and compliance from our cohort of athletes, whose mean weekly response rate was 91.5%. Overall, 114 training days were lost because of illness or injury within the 20 weeks and, on average, 5 athletes per week (20.8%) reported health problems.

Conclusions

This study demonstrates that the translated German version of the OSTRC Questionnaire is a reliable and valid tool with high internal consistency for the medical monitoring of German athletes. The OSTRC-G now offers the opportunity for a continued surveillance of high-level German athletes.
SCAT2 and SCAT3 scores at baseline and after sports-related mild brain injury/concussion: qualitative synthesis with weighted means
Authors: Thomas Roger E , Alves Jorge , Vaska Marcus M , Magalhães Rosana
Published: October 2016

Objective

Identify all Sport Concussion Assessment Tool (SCAT2/3) studies, compare baseline and postconcussion results.

Design

Systematic review (qualitative synthesis, weighted means).

Data sources

18 databases, 9 grey literature resources searched for SCAT2/3 data; 9150 articles identified, titles/abstracts assessed/data-entry independently by two reviewers.

Eligibility criteria for selecting studies

Any studies reporting partial/complete SCAT2/3 data.

Results

21 studies with data (partial/complete data 16 SCAT2 (4087 athletes); 5 SCAT3 (891). Newcastle-Ottawa risk-of-bias scale: studies with maximum possible score of 4, 85% scored 3 or 4; studies with maximum possible score of 6, 75% scored 5 or 6. SCAT2 high schoolers: weighted mean score for symptoms 18.46 (22=no symptoms), Balance Error Scoring System (BESS) 26.14, Standardised Assessment of Concussion (SAC) 26.00 and SCAT2 total 88.63. Collegiate/adults weighted means: symptoms 20.09, BESS 25.54, SAC 27.51 and total SCAT2 91.20. Between-study and within-study variability similar to those of the high schoolers. Limited variability between genders. Only 2 studies report baseline and postconcussion scores and 9 partial scores, but data are too limited to provide weighted average scores.

Conclusions

Group mean baseline SCAT scores for high school and collegiate athletes are similar, with minimal gender differences; baseline symptoms show more variability than other components. There are minimal data for elementary students and professionals, no data for adult non-collegiate athletes. Two studies provide preconcussion and postconcussion scores. No data on minimal significant clinical differences to guide players/coaches in withdrawing from a game in progress and deciding when recovery is complete and play can be resumed. The SCAT needs supplementing with clinical and neuropsychological return-to-play assessments.