bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Low Load Limit of Gasoline Partially Premixed Combustion Using Negative Valve Overlap
Authors: Borgqvist Patrick , Andersson Öivind , Tunestål Per , Johansson Bengt 
Published: July 2013

Partially premixed combustion has the potential of high efficiency and simultaneous low soot and NOx emissions. Running the engine in PPC mode with high octane number fuels has the advantage of a longer premix period of fuel and air which reduces soot emissions, even at higher loads. The problem is the ignitability at low load and idle operating conditions.
The objective is to investigate different multiple-injection strategies in order to further expand the low load limit and reduce the dependency on negative valve overlap in order to increase efficiency. The question is, what is the minimum attainable load for a given setting of negative valve overlap and fuel injection strategy. The experimental engine is a light duty diesel engine equipped with a fully flexible valve train system. The engine is run without boost at engine speed 800 rpm. The fuel is 87 RON gasoline.
A turbocharger is typically used to increase the boost pressure, but at low engine speed and load the available boost is expected to be limited. The in-cylinder pressure and temperature around top-dead-center will then be too low to ignite high octane number fuels. A negative valve overlap can be used to extend the low engine speed and load operating region. But one of the problems with negative valve overlap is the decrease in gas-exchange efficiency due to heat-losses from recompression of the residual gases. Also, the potential temperature increase from the trapped hot residual gases is limited at low load due to the low exhaust gas temperature. In order to expand the low load operating region further, more advanced injection strategies are investigated.
Methyl Oleate Evaluation as a Model Fuel for Peanuts FAME, in an Indirect Injection Diesel Engine
Authors: Soloiu Valentin , Weaver Jabeous , Duggan Marvin , Ochieng Henry , Vlcek Brian , Williams David , Jansons Marcis 
Published: July 2013

This study investigates the combustion characteristics of methyl oleate (oleic FAME) produced from oleic acid. This compound is the main fatty acid component of peanut FAME, a potential renewable biofuel. Methyl oleate has been suggested in our previous work as a reference fuel or surrogate for biodiesel for advanced research (simulation and experiments), or as an enrichment compound to improve biodiesel’s fuel properties. This investigation compares the combustion and emissions characteristics of methyl oleate to peanut FAME and ultra-low sulfur diesel No. 2 (ULSD), in a single-cylinder indirect injection diesel engine intended for use as an auxiliary power unit. The dynamic viscosity of peanut FAME (P100) and Methyl Oleate (O100) was found to be 5.2 cP and 4.3 cP, respectively, at 40°C. It was determined from the ASTM standards for biodiesel that up to 50% FAME could be run in the engine. The lower heating value of P100 and O100 was 36 MJ/kg and 37 MJ/kg respectively, compared to 42.7MJ/kg for ULSD. With a combustion time of 2ms, P50 and O50 have shown similar combustion characteristics with ignition delays of about 1 ms at 2200rpm, 6.2 imep (100% load). The P50, O50, and ULSD heat release, with premixed phase combining with diffusion combustion, produced maximum values of 20.3 J/CAD, 22.7 J/CAD, and 21.9 J/CAD respectively. The heat fluxes were calculated by the Annand model, and a 2% increase in maximum total heat flux was observed for O50 compared with a maximum value of 1.95 MW/m2 for ULSD and P50. The mechanical efficiency of 77% was similar for all tested FAME blends and ULSD. The NOx increased for P20 by 6% compared with ULSD while for P50 it was similar to the ULSD values. The NOx emissions of methyl oleate showed a similar trend with that of ULSD. The soot values were relatively constant for all of the methyl oleate blends and increased by 14% for P50 when comparing both fuels to ULSD.
The findings support the use of methyl oleate as a reference or model fuel for combustion modeling, and as a compound for enriching biodiesel.
Development of the New Welding Control Method for HF-ERW Pipes: Advanced Welding Process of HF-ERW 1
Authors: Fukami Toshisuke , Mizuhashi Nobuo , Hasegawa Noboru , Hamatani Hideki , Hasegawa Yasushi , Asano Takuya , Motoyoshi Suguru , Miura Takao , Tanaka Kimiharu , Nakaji Tomohiro , Yamamoto Kazuto 
Published: July 2013

In recent years, the key application requirement of the ERW line pipe has been its toughness, including the weld seam.
It is known that, among defects generated at the weld seam, the penetrator defect affects toughness and is difficult to control by welding condition[1–4].
Generally speaking, ERW pipes are welded with exposure to air, and oxides are produced on the surface of the melted metal during the process. The discharge of this melted metal by electromagnetic force and squeezing produced at the current welding route is effective in eliminating the penetrator, and constantly optimizing the welding heat input means this defect can be constantly reduced.
To optimize the welding heat input, therefore, it is important to determine the welding phenomena occurring at the welding spot and contrast them with the defect area ratio. We have studied (examined) the welding phenomena, optimum heat input power and the welding defect generation mechanism. Consequently, it was revealed that by varying the welding speed, Vee convergence angle and welding heat input, etc., a new categorization of welding phenomena as Types 1, 2, 3, and 2′ was possible.
In the case of Type 2 and 2′ welding phenomena, the welding defect area ratio decreases, which resulted in a sound seam weld with high toughness. If these two welding phenomena are compared, the wider heat input power range of Type 2′ is preferable for the HF-ERW manufacturing process. The higher heat input of Type 2′ compared to Type 2 compensates for the abutting surface angle fluctuation, meaning it is also preferable for pipe manufacturing. Consequently, the control of the Type 2′ welding phenomenon is preferable for the HF-ERW manufacturing process.
Using Quantitative Risk Assessment to Justify Location Class Changes: Case Study
Authors: Rumney Paul , Goodfellow Graham 
Published: July 2013

Expansion of existing residential and commercial areas, or the construction of new developments in the vicinity of high pressure gas transmission pipelines can change a Location Class 1 into a Class 2 or Class 3 location. Operators are left with a pipeline that no longer meets the requirements of its design code.
Reducing the maximum allowable operating pressure of a pipeline, or re-routing it away from the population, can meet the requirements of a design code, such as CSA Z662 or ASME B31.8, but such options have both high costs and significant operational difficulties.
Quantitative risk assessment has been employed successfully for many years, by pipeline operators, to determine risk based land use planning zones, or to justify code infringements caused by new developments. By calculating the risk to a specific population from a pipeline, and comparing it with suitable acceptability criteria, a pipeline may be shown to contribute no more risk to a population than other pipelines operating entirely in accordance with the design codes.
Risks may be demonstrated to be ‘as low as reasonably practicable’, through the use of cost benefit analysis, without additional mitigation, allowing precious pipeline maintenance funds to be spent most effectively in areas where they will have the highest impact on risk.
This paper shows how quantitative risk assessment may be used to justify continued safe operation of a pipeline at its original operating stress following a change of class designation, illustrated with a case study from Western Europe.
Pressure Test Planning to Prevent Internal Corrosion by Residual Fluids
Authors: Place Trevor , Sasaki Greg , Cathrea Colin , Holm Michael 
Published: July 2013

Strength and leak testing (AKA ‘hydrotesting’, and ‘pressure testing’) of pipeline projects remains a primary method of providing quality assurance on new pipeline construction, and for validating structural integrity of the as-built pipeline [1][2][3]. A myriad of regulations surround these activities to ensure soundness of the pipeline, security of the environment during and after the pressure testing operation, as well as personnel safety during these activities. CAN/CSA Z662-11 now includes important clauses to ensure that the pipeline designer/builder/operator consider the potential corrosive impacts of the pressure test media [4].
This paper briefly discusses some of the standard approaches used in the pipeline industry to address internal corrosion caused by pressure test mediums — which often vary according to the scope of the pipeline project (small versus large diameter, short versus very long pipelines) — as well as the rationale behind these different approaches. Case studies are presented to highlight the importance of considering pressure test medium corrosiveness. A practical strategy addressing the needs of long-distance transmission pipeline operators, involving a post-hydrotest inhibitor rinse, is presented.
Development of a Probabilistic Model for Stress Corrosion Cracking of Underground Pipelines Using Bayesian Networks: A Concept
Authors: Jain Swati , Ayello Francois , Beavers John A. , Sridhar Narasi 
Published: July 2013

Stress corrosion cracking (SCC) continues to be a safety concern, mainly because it can remain undetected before a major pipeline failure occurs. SCC processes involve complex interactions between metallurgy, stress, external soil environment, and the electrolyte chemistry beneath disbonded coatings. For these reasons, assessing SCC failure probability at any given location on a pipeline is difficult.
In an attempt to assess the SCC probability, a Bayesian network model was created. The model links events by cause-consequence connections. The strengths of these connections are adjusted using expert knowledge, analytical models, and data from the field. Bayesian network modeling was chosen because it takes into account the high degree of uncertainty in the input parameters. Other models have been developed to assess SCC: such as indexing methods, heuristics models, and mechanistic models. However, their main limitation is the uncertainty of the input parameters. One other strength of the Bayesian model is that calculations can be run in two directions: the forward direction from cause to consequence and the backward direction from observation to causative factors. In the forward direction, the model evaluates the probability of SCC failure using various input probabilities of factors that are important to SCC. In the backward direction, the model can evaluate the effect of any known occurrence of SCC failure on the probabilities of causative factors and thus condition the Bayesian network to evaluate the future failure probability.
In this paper, we discuss a Bayesian network model for high-pH SCC. The conceptual framework, acquisition of data, and the inclusion of uncertainties are described. In addition, an example of the model application to high pH SCC is given. The effects of service and field conditions such as soil type, soil chemistry, coating type, surface preparation techniques, stresses, residual stress due to pipe manufacturing conditions, welds, dents, location such as proximity to rivers, wetting and drying cycles, etc. on the SCC probability can be assessed with the model. The model details shown in this publication will only cover the stress affect due to surface preparation, welds, dents, and manufacturing conditions and temperature effect. The effects of other factors and validation against field experience will be discussed in future publications.
Qualification of an Application System for In-Field External Reinforcement of Pipelines Using Helical Steel Wrap
Authors: Miles David J. 
Published: July 2013

A solution, known as XHab™, has been developed for external repair and reinforcement of pipelines using ultra high strength steel strip. This method involves wrapping multiple layers of strip in a helical form continuously over an extended length of pipeline using a dedicated forming and wrapping machine. The reinforcement provided by the strip can be used to:
a) Restore the original maximum allowable operating pressure to a section of defective pipe (e.g. external corrosion or denting), or
b) Reinforce an intact but de-rated section of pipeline (e.g. a Location Class change through encroachment) to maintain reduced hoop stress in the base pipe as required by codes and regulations, but allow reinstatement of the original operating pressure by carrying the additional load in the strips.
This paper describes the full-scale qualification testing, including in-field proving runs, and design analysis necessary to demonstrate the field-readiness of the application system and reinforcement product. This includes wrapping and pressure testing of pipe with machined external wall defects. The potential for XHab repair of stress corrosion cracking (SCC) is also discussed for an upcoming series of tests on pipe samples with electrical discharge machined notches.
To demonstrate reinforcement of intact pipe, a 40ft joint of 26-inch vintage flash-butt seam welded pipe, instrumented with hoop and axial strain gages, has been wrapped by the XHab machine with sufficient reinforcement to simulate a change from Location Class 1, Div. 2 to Location Class 3 (ASME B31.8). This pipe has been subjected to pressure cycling and ultimate burst alongside an identical unwrapped pipe sample which provides a baseline. The test results are presented and compared to finite element analysis.
Potential Components of an Effective LSW Integrity Management Program
Authors: Podnar Tara , Bubenik Thomas A. , Andrew Jim , Hicks Dyke 
Published: July 2013

Det Norske Veritas (U.S.A.), Inc. (DNV) has had the opportunity to observe and contribute to a significant number of longitudinal seam weld integrity management programs. DNV has used these opportunities to identify activities with a positive impact on the integrity management of the longitudinal seam welds for which they are implemented.
The Integrity Assessment activities identified by DNV include those pertaining to hydrostatic pressure testing, in-line inspection data, and in-line inspection technology. The Anomaly Review and Prioritization activities include excavation prioritization, control excavations, and investigative excavations. The Excavation and Repair Program activities include non-destructive examination techniques, technologies and validation, repair methods, and safety measures. The Tool Validation activities include in-line inspection specification and vendor feedback. The Reassessment activities include those pertaining to in-line inspection validation, operations, and reassessment interval calculation methodologies.
Not all longitudinal seam weld integrity management activities are appropriate for all pipelines. In these cases, the correct combination of integrity management activities will result in an effective longitudinal seam weld integrity management program.
ILI Based Dent Screening and Strain Based Analysis
Authors: Tinacos Katina , Cazenave Pablo , Gao Ming , Krishnamurthy Ravi , Seman Dan , Jones Charley 
Published: July 2013

Pipeline operators often deal with the large numbers of dents that require further consideration, and are required to prioritize these dents for further investigation and repair. Code guidance is clear on the relative severity of dents based on a depth or associated with welds, corrosion, gouging or cracking. It allows the pipeline operators to prioritize their dig lists and limit the number of “investigative digs” by omitting plain and shallow dents. However, the dent depth criterion has limitations, experiences learned in the past have shown that a dent prioritization based on depth alone, may still leave a significant number of dents in the pipeline which may pose a threat, particularly from local static strain and fatigue.
In recent years, strain and fatigue analyses have been included in the assessment of severity of dents in order to better prioritize and effectively repair dents which represent a threat to the structural integrity of pipelines. However, strain analyses require tedious calculation of dent curvature at each data point from ILI reported dent profile. When a large numbers of dents require to be prioritized by strain severity, using this detail calculation is impractical. Therefore, a screening methodology is required to reliably identify candidate dents that require detail strain assessment.
In this paper, an aspect-ratio based screening methodology is developed and applied to over 7,000 dents reported by an In-Line Inspection (ILI) caliper tool for a 265 miles long pipeline section. A total of 263 shallow dents which could have injurious strain level were identified and ranked for detail strain and fatigue calculations.
In-ditch investigation of 20 dents with LaserScan profiling showed that the developed screening methodology provides an effective tool to capture all the dents with strain equal and 6.5% at 95% confidence level.
Online Application of Hydraulic Simulation Software to Gassco’s Subsea Pipeline Network
Authors: Birchenough Eadred , Munro James , Zhang Jun , Hansen Dagfinn , Rinde Ola , Sakariassen Vidar , Velde Ben 
Published: July 2013

This paper addresses the on-line application of ATMOS SIM simulation software, integrated with ABB Network Manager WS500, to a subsea pipeline network of 7,800 km (4,847 mile) length — see Figure 1. The pipeline system is operated by Gassco Norway, and it delivers an annual volume of approximately 100 billion standard cubic meters of Norwegian gas to customers in Western Europe. One of the main challenges to such a great subsea pipeline system is the limited measurements available. For nearly all of the pipelines, the only location where flow, pressure and temperature are measured is at the inlet and outlet which could be more than 800 km (497 mile) apart.
The following applications will be addressed in this paper:
• IT architecture. User controls including Common Alarm List.
• Data validation overview.
• Pipeline inventory calculation.
• Continuous calculation of settle-out-pressures for (sub)sections of pipelines to provide information for emergency shutdown systems.
• Integration of ambient seabed temperatures as provided by UK Met.
• Composition tracking including the possibility to track user specified trace components.
• Estimated arrival times and volumes of “off-specification” gas.
• Tracking of the parentage of batches such that the party responsible for off-spec gas can be identified (polluter pays principle).
• Facilities to restart models from historic data with the possibility to remove erroneous inputs.
• Continuous running of look-ahead cases based on user defined transient time series and nominations for contractual exit points.
• Using larger network models to plan and monitor mixing of gasses to prevent off-spec gas.
Comparisons between simulated and measured values will be made to illustrate the accuracy of the hydraulic models. In addition, the application of Maximum Likelihood State Estimation will be discussed to demonstrate its effectiveness in overcoming measurement errors.
Detection of Trace Hydrocarbons and Toxic Components in the Environment
Authors: Knoblach Walter , Bryce Peter W. 
Published: July 2013

The risk of hydrocarbon and toxic spills increases with the aging of oil and chemical plant related infrastructure. The need for early detection of hydrocarbon and toxic chemical pollution is paramount, particularly in view of potential environmental damage, cleanup costs, and the loss of public confidence in industry’s ability to quickly respond to leaks.
Rigorous right-of-way monitoring, control of third party activities within proximity of pipelines, in conjunction with a robust preventative maintenance program is key to leak prevention. The first line of defense in the event of a leak is early detection and operational response to limit product loss from the pipe. Sophisticated mathematical modeling of flow regimes coupled with multiple pressure sensory relay devices in pipelines has increased the sensitivity of these leak detection technologies. However, despite these technological improvements significant leaks have occurred recently on major pipeline systems with damaging consequences.
Operators are challenged to interpret and respond to leak alarms in the absence of corroborating information. Frequent false or ambivalent “indications” can foster complacency, and worse, inaction.
The authors contend that reliance on a single technology for detecting leaks is imprudent and unacceptable in certain environments given the consequences of a late response to a loss of product from the line. Leak detection can be significantly enhanced by the application of molecular sensory technology in tandem with real time pipeline monitoring systems. The systems are synergistic and do not compete with each other.
This paper describes the development of the LEOS® leak detection system, its application and operational experience in high sensitivity locations. Four distinct applications are described, including: an Arctic subsea pipeline, an arctic above ground pipeline, a river crossing, and a buried onshore pipeline right of way. In the latter, a situation is described where a hydrocarbon leak was discovered on an adjacent third party pipeline not directly monitored by the system.
New Concrete Crosstie Regulations and Rail Cant Measurement
Authors: Clouse Arthur L. 
Published: July 2013

The new concrete crosstie rules require, in FRA Class 1-5 track standards, specific performance requirements that address the unique characteristics of fastener reliability, concrete crosstie, and roadbed stability. [Inspectors] should be aware of the three modes of concrete crosstie failure: support, stability, and electrical isolation. The compressive strength of concrete and the amount of prestress in its section composition provide the strength and stiffness necessary to support expected wheel loads. There’s a balance between excessive stiffness that can lead to higher stresses at the bottom of the crosstie and at the rail seat.
Conversely, a loss of stiffness, caused by ever increasing axle loading, can lead to excessive rail deflections and damage to the ballast and subgrade. Inspectors should be aware that failure modes are not isolated to crosstie defects. Combinations of compliant but irregular track and rail geometry, poor drainage, insufficient ballast depth and subgrade soil conditions may contribute to failure or root causal factors.
The new concrete crosstie regulations contained in Part 213.109(d) and a section by section description is as follows:
Part 213—[AMENDED]
§ 213.109 CROSSTIES
d) Concrete crossties counted to satisfy the requirements set forth in paragraph (b)(4) of this section shall not be—
(1) Broken through or deteriorated to the extent that prestressing material is visible;
(2) Deteriorated or broken off in the vicinity of the shoulder or insert so that the fastener assembly can either pull out or move laterally more than 3/8 inch relative to the crosstie;
(3) Deteriorated such that the base of either rail can move laterally more than 3/8 inch relative to the crosstie on curves of 2 degrees or greater; or can move laterally more than 1/2 inch relative to the crosstie on tangent track or curves of less than 2 degrees;
(4) Deteriorated or abraded at any point under the rail seat to a depth of 1/2 inch or more;
(5) Deteriorated such that the crosstie’s fastening or anchoring system, including rail anchors (see § 213.127(b)), is unable to maintain longitudinal rail restraint, or maintain rail hold down, or maintain gage due to insufficient fastener toeload; or
(6) Configured with less than two fasteners on the same rail except as provided in § 213.127(c).