bluuebunny/crossref_metadata_2025_split huggingface dataset:
Association between asthma control and asthma cost: Results from a longitudinal study in a primary care setting
Authors: Nguyen Hai V. , Nadkarni Nivedita V. , Sankari Usha , Mital Shweta , Lye Weng K. , Tan Ngiap C. 
Published: November 2016

ABSTRACT
Background and objectiveAsthma control can be assessed with the Asthma Control Test (ACT) and a score of 20 or higher indicates good asthma control. Patients pay for their consultation and treatment in the fee‐for‐service primary healthcare system in Singapore. We hypothesized that achieving asthma control would result in lower asthma costs through reduced acute exacerbations, fewer physician consultations and lower lost productivity. The study compared the healthcare costs of patients who achieved asthma control and those with suboptimal asthma control based on ACT scores. Factors influencing asthma control and healthcare expenditure over time were also examined.MethodsA total of 736 patients were enrolled into an asthma care programme in two polyclinics during 2008 and 2013. Direct costs of asthma management were derived from the frequency of polyclinic consultations, medication costs and hospitalization. Indirect costs were estimated from lost workdays due to exacerbations. The generalized estimating equation (GEE) approach was used to longitudinally model the factors associated with total healthcare expenditure.ResultsPatients with asthma control spent S$48 (US$36) more per doctor visit on asthma drugs (P < 0.01) but incurred S$65 (US$48) less per doctor visit in total costs (P < 0.01) than those with suboptimal asthma control. The savings from achieving asthma control for obese patients were greater than for normal‐weight patients (S$42 or the equivalent of US$31; P < 0.05).ConclusionOptimal asthma control was associated with reduced healthcare costs. An effective treatment regimen should also consider other modifiable factors such as weight control to achieve asthma control and eventually reduce asthma costs.
Application of Graph Theory to Cost‐Effective Fire Protection of Chemical Plants During Domino Effects
Authors: Khakzad Nima , Landucci Gabriele , Reniers Genserik 
Published: November 2016

AbstractIn the present study, we have introduced a methodology based on graph theory and multicriteria decision analysis for cost‐effective fire protection of chemical plants subject to fire‐induced domino effects. By modeling domino effects in chemical plants as a directed graph, the graph centrality measures such as out‐closeness and betweenness scores can be used to identify the installations playing a key role in initiating and propagating potential domino effects. It is demonstrated that active fire protection of installations with the highest out‐closeness score and passive fire protection of installations with the highest betweenness score are the most effective strategies for reducing the vulnerability of chemical plants to fire‐induced domino effects. We have employed a dynamic graph analysis to investigate the impact of both the availability and the degradation of fire protection measures over time on the vulnerability of chemical plants. The results obtained from the graph analysis can further be prioritized using multicriteria decision analysis techniques such as the method of reference point to find the most cost‐effective fire protection strategy.
A Bayesian Model and Stochastic Exposure (Dose) Estimation for Relative Exposure Risk Comparison Involving Asbestos‐Containing Dropped Ceiling Panel Installation and Maintenance Tasks
Authors: Boelter Fred W. , Xia Yulin , Persky Jacob D. 
Published: November 2016

AbstractAssessing exposures to hazards in order to characterize risk is at the core of occupational hygiene. Our study examined dropped ceiling systems commonly used in schools and commercial buildings and lay‐in ceiling panels that may have contained asbestos prior to the mid to late 1970s. However, most ceiling panels and tiles do not contain asbestos. Since asbestos risk relates to dose, we estimated the distribution of eight‐hour TWA concentrations and one‐year exposures (a one‐year dose equivalent) to asbestos fibers (asbestos f/cc‐years) for five groups of workers who may encounter dropped ceilings: specialists, generalists, maintenance workers, nonprofessional do‐it‐yourself (DIY) persons, and other tradespersons who are bystanders to ceiling work. Concentration data (asbestos f/cc) were obtained through two exposure assessment studies in the field and one chamber study. Bayesian and stochastic models were applied to estimate distributions of eight‐hour TWAs and annual exposures (dose). The eight‐hour TWAs for all work categories were below current and historic occupational exposure limits (OELs). Exposures to asbestos fibers from dropped ceiling work would be categorized as “highly controlled” for maintenance workers and “well controlled” for remaining work categories, according to the American Industrial Hygiene Association exposure control rating system. Annual exposures (dose) were found to be greatest for specialists, followed by maintenance workers, generalists, bystanders, and DIY. On a comparative basis, modeled dose and thus risk from dropped ceilings for all work categories were orders of magnitude lower than published exposures for other sources of banned friable asbestos‐containing building material commonly encountered in construction trades.
Characterisation of maternal human leukocyte antigen class I antibodies in suspected foetal and neonatal alloimmune thrombocytopenia
Authors: Refsum E. , Mörtberg A. , Dahl J. , Meinke S. , Auvinen M.‐K. , Westgren M. , Reilly M. , Höglund P. , Wikman A. 
Published: November 2016

SummaryObjectivesTo investigate the specificities and level of HLA class I antibodies in selected cases referred for suspected foetal and neonatal alloimmune thrombocytopenia (FNAIT).BackgroundFNAIT occurs in 1 : 1–2000 live births, whereas maternal immunisation against human leukocyte antigen (HLA) class I is common. Whether HLA class I antibodies alone can cause FNAIT is debatable.Material and methodsA total of 260 patient samples were referred between 2007 and 2012. Referrals with maternal HLA class I antibodies and no other cause for the neonatal thrombocytopenia were included for analysis (cases, n = 23). HPA‐1a negative mothers were excluded. Control groups were screened positive mothers of healthy neonates (controls, n = 33) and female blood donors (blood donors, n = 19). LABScreen single antigen HLA class I beads was used for antibody analysis. Clinical records were reviewed for cases.ResultsAll groups had broad antibody reactivity. Cases had more antibodies with high SFI levels compared with the controls (SFI>9999; medians 26, 6 and 0; P < 0·05) and higher overall median HLA‐ABC and HLA‐B SFI (P < 0·05). Many of the antibodies were reactive with rare alleles. When reviewing the clinical records, several of the cases had other contributing factors to the thrombocytopenia. There was no correlation between foetal platelet count and antibody levels.ConclusionMothers of thrombocytopenic neonates had higher levels of HLA class I antibodies compared with control groups of women with healthy children and female blood donors. However, clinical outcome and antibody response correlated poorly in the heterogeneous case group, indicating a multifactorial cause to the thrombocytopenia in the majority of cases.
Controlling Rumex obtusifolius by means of hot water
Authors: Latsch R , Anken T , Herzog C , Sauter J 
Published: November 2016

SummaryHot‐water treatment of broad‐leaved dock (Rumex obtusifolius) was developed as an alternative to manual digging out in organic farming. During treatment, the top region of the root was heated so that the plants would die back. The aim of this study was to validate the efficacy of the hot‐water treatment of dock roots. The trials were carried out with a commercially available hot‐water high‐pressure cleaner and a rotating nozzle for water application. The target plant control rate assessed 12 weeks after treatment was set at >80%. The appraisal covered 1330 treated plants of varying size from four sites with three different soil texture classes. Parameters which influenced the control rate were water temperature, amount of water, soil moisture and soil texture. Additional parameters recorded were the amount of fuel oil consumption and working time requirements. A reassessment of the plants 1 year after treatment yielded information concerning the ground cover, the possible germination of new dock plants from buried seeds and the soil structure of the site treated. In order to achieve the target control rate of >80%, it is recommended that the temperature of the water leaving the equipment should exceed 80°C. The amount of water required depends on root size and soil moisture. On average, 131 plants per hour can be treated with no negative effects on regrowth or soil structure. Hot‐water treatment is the first functional control alternative to manual digging out R. obtusifolius for organic farming.
Risk-Based Mitigation of Mechanical Damage
Authors: Ma Jing , Zhang Fan , Desjardins Guy 
Published: November 2016

According to the PHMSA data on reportable incidents, for the 20 years ranging from 1995 to 2014, excavation damage accounted for 16.4% of the incidents on 301,732 miles of gas transmission pipelines and 15.6% of the incidents on 199,210 miles of hazardous liquid pipelines. On the whole, excavation damage is a major cause of incidents, ranking third following incidents caused by material/weld/equipment failure and corrosion.
For the purposes of this study, mechanical damage is separated into two categories, i.e. immediate failures and delayed failures. An immediate failure is one which occurs at the instant the damage is done to the pipeline. A puncture, for example, is an immediate failure. Delayed failures involve damage that is not sufficient to cause a leak or a rupture at the time it is inflicted. On average, 14.6% of the mechanical damage incidents in gas transmission pipelines and 13.3% of the mechanical damage incidents in hazardous liquid pipelines can be classified as delayed failures.
The immediate failures are generally minimized through the preventative measure and design efforts. For instance, it is shown herein that the puncture probability can be calculated through the comparison between the likelihood of any given external load being imposed and inherent pipe resistance.
While preventative measures serve to reduce the occurrences of delayed failures as well as the occurrences of immediate failures, delayed failures are largely mitigated through in-line inspection and timely remediation actions. The fact that the assessment methods for mechanical damage are generally not as robust as those for cracks and corrosion tends to limit the reliability of deterministic calculations of response times. Therefore, in the study described herein, risk-based approaches to minimizing delayed failures were developed. Three different approaches to deciding which dents need to be excavated after an ILI were pursued. One involves the use of reportable incident rates based on the PHMSA statistics in conjunction with the number of ILI dent indications per mile to get a probability of failure. The second consists of a decision-making process based on the ILI-reported dent depths and the dent fatigue life probability-of-exceedance function. The third relates to a decision-making process based on successive excavations of dents located by ILI, in which the Bayesian method is applied to compare predicted versus actual severity and thereby determine the probability of failure associated with stopping after a specific number of excavations.
CTOA Test Method Using Drop-Weight Tear Test (DWTT): Background and Development of Standard
Authors: Xu S. , Tyson W. R. , Simha C. H. M. , Gesing M. , Liang J. 
Published: November 2016

Arrest of fast ductile fracture in the design of gas pipelines has traditionally been assured by specifying Charpy absorbed energy (Cv) of pipe steel based on the Battelle two-curve method. However, the Charpy test has been shown to be inadequate to characterize crack propagation in modern high-strength, high-toughness pipe steels. For steels with Cv more than approximately 100 J, fracture arrest methodologies based on Cv can lead to non-conservative predictions. The problem is that the Charpy specimen is too small to characterize full-scale fracture, and for tough steels the ductility can be so high that the Charpy specimen bends without fracturing completely. To overcome these limitations, the use of a larger full-thickness specimen, the “Drop-Weight Tear Test” (DWTT) specimen, has been proposed. The test is instrumented to measure the force on and displacement of the impactor during crack propagation. The data is interpreted to yield the “crack-tip opening angle” (CTOA), which is constant during steady-state crack growth and characterizes the propagation resistance. The CTOA has been proposed for some time as a suitable property to assess fracture propagation and arrest in high-pressure gas pipelines, but up to now a standard test method for measurement of the CTOA has not been available. To remedy this situation, a draft standard has been developed by the authors and is being balloted by ASTM E081.
In this paper, the CTOA parameter and CTOA-based fracture arrest methodology will be introduced briefly. The background and development of the draft ASTM standard test method for determination of CTOA using the drop-weight tear test (DWTT) specimen will be reviewed including the procedure and the results of an international round robin. In the CTOA test method, the only adjustable parameter is the rotation factor (rp). Using a modified Xue-Wierzbicki damage mechanics model and a statistical analysis, rp has been determined to be a weak function of yield strength, Charpy absorbed energy and specimen thickness. Although no physical model has been developed to explain the interplay of these factors, they are all related to the extent and distribution of plastic deformation ahead of the crack. The technical background and quantification of rp will be described in this paper. It is intended to apply the CTOA test method to a broad range of steels, including thin (less than 6 mm) and thick (larger than 20 mm) pipe steels.
Identifying and Sizing Axial Seam Weld Flaws in ERW Pipe Seams and SCC in the Pipe Body Using Ultrasonic Imaging
Authors: Haines Harvey , Hörchens Lars , Tomar Pushpendra 
Published: November 2016

A significant portion of the global energy pipeline infrastructure is constructed with pipe materials manufactured using the Electric Resistance Weld (ERW) process. The longitudinal seam of these ERW pipelines may contain manufacturing flaws and anomalies that can grow over time through pressure cycle fatigue and result in a pipeline integrity failure. These flaws/anomalies can be present in both vintage pipe (generally pre-1970) manufactured using a low frequency ERW process and more modern pipe that is manufactured using a high frequency ERW process. ERW seam anomalies are challenging to detect, discriminate, and size with current In-Line Inspection and In-Ditch NDE inspection technologies, which is driving the industry to better understand current inspection industry performance and to develop new technologies for ERW seam anomaly inspection.
Ultrasonic (UT) imaging using inverse wave field extrapolation (IWEX) is an emerging NDE technique that is being applied to improve discrimination and sizing of anomalies in pipelines. This paper will describe the IWEX development, the challenges related to seam weld integrity and assessment and SCC assessment, and results from studies to evaluate performance. Ultrasonic imaging is also compared to the current state-of-the-art techniques such as ultrasonic phased array (PA). A goal of the project is to produce images capable of discriminating cold welds, surface breaking hook cracks, non-surface breaking upturned fiber indications, poor trim, offset plate edges, and anomalies with fatigue cracking. The goal is to size all of the cracks in a SCC colony and produce a three-dimensional map of the area. In mapping these anomalies the sizing needs to be sufficiently accurate to qualify in-line inspection tools used for crack inspection.
Findings From an Investigation of Hydrotest Protocols
Authors: Olson Richard J. , Young Bruce A. , Leis Brian 
Published: November 2016

Experience has shown that in-service failures can occur in Electric Resistance Welded (ERW) line pipe shortly after a hydrotest as a part of line rehabilitation or in retesting to return to service. This can occur due to near-critical features that grew but remained in the line, or due to a pressure-reversal due to stable defect growth during the pressure test. The objective of this study was to improve hydrotesting protocols by developing and optimizing procedures for conducting hydrotests of pipe with ERW or Flash Welded (FW) seam defects, and validating the practical utility of the proposed procedures.
This work has enhanced and adapted both failure and growth models to predict the behavior of defect shapes based on collapse and fracture theories, to assess idealized cold welds, hook cracks, and selective-seam weld corrosion (SSWC), and parametrically quantify differences and similarities in their response to increasing pressure. Based on insight from these analyses, this work has established a pressure-time sequence that incorporates the spike concept to expose near-critical defects to pressures that will cause them to fail and it has evaluated the sensitivity as a function of defect size with respect to time-dependent growth. In turn, insights from the outcomes of these analyses were used to identify potential hydrotest protocols.
Development of Grade X80 High Charpy Energy Linepipe by MA Formation Control
Authors: Kimura Hideyuki , Yokota Tomoyuki , Ishikawa Nobuyuki , Kakihara Shinichi , Kondo Joe 
Published: November 2016

Higher grade linepipes such as grade X80 have been developed and applied to long distance pipelines in order to reduce the cost of pipeline construction by using thinner pipes than is possible with conventional grades. Service pressures have also been increased in recent years for efficient gas transportation. In addition to the requirement of higher strength, running ductile fracture should be prevented in long distance and high pressure pipelines. Resistance to ductile fracture, as evaluated by Charpy energy, is an important material property for higher grade linepipes.
It has been reported that bainite single-phase steel tends to show higher Charpy energy than ferrite-bainite or bainite-MA (martensite-austenite constituent) dual-phase steels, since void nucleation is suppressed in single-phase steels compared with dual-phase steels. However, in higher grade steels with a bainite single phase, a small amount of MA grains generally remains due to the chemical stability of MA. Therefore, further reduction of MA is key to improving Charpy energy for higher grade linepipe steels. In order to achieve high Charpy energy by MA formation control, the optimum conditions of the plate manufacturing process were investigated. As a result, a high Charpy energy was achieved by the combination of controlled rolling and precise control of the accelerated cooling conditions, by which the MA phase was minimized.
Based on the above investigation, grade X80 high Charpy energy linepipes were trial-produced by applying JFE Steel’s optimized accelerated cooling (ACC) system with a high cooling rate and homogeneous temperature profile. Stable higher Charpy energy was achieved by minimizing MA formation and achieving a homogeneous microstructure by advanced cooling control.
Near Real-Time Automated Detection of Small Hazardous Liquid Pipeline Leaks Using Remote Optical Sensing and Machine Learning
Authors: Araujo Maria S. , Siebenaler Shane P. , Dupont Edmond M. , Blaisdell Samantha G. , Davila Daniel S. 
Published: November 2016

The prevailing leak detection systems used today on hazardous liquid pipelines (computational pipeline monitoring) do not have the required sensitivities to detect small leaks smaller than 1% of the nominal flow rate. False alarms of any leak detection system are a major industry concern, as such events will eventually lead to alarms being ignored, rendering the leak detection system ineffective [1].
This paper discusses the recent work focused on the development of an innovative remote sensing technology that is capable of reliably and automatically detecting small hazardous liquid leaks in near real-time. The technology is suitable for airborne applications, including manned and unmanned aircraft, ground applications, as well as stationary applications, such as monitoring of pipeline pump stations. While the focus of the development was primarily for detecting liquid hydrocarbon leaks, the technology also shows promise for detecting gas leaks.
The technology fuses inputs from various types of optical sensors and applies machine learning techniques to reliably detect “fingerprints” of small hazardous liquid leaks. The optical sensors used include long-wave infrared, short-wave infrared, hyperspectral, and visual cameras. The utilization of these different imaging approaches raises the possibility for detecting spilled product from a past event even if the leak is not actively progressing.
In order to thoroughly characterize leaks, tests were performed by imaging a variety of different types of hazardous liquid constitutions (e.g. crude oil, refined products, crude oil mixed with a variety of common refined products, etc.) in several different environmental conditions (e.g., lighting, temperature, etc.) and on various surfaces (e.g., grass, pavement, gravel, etc.). Tests were also conducted to characterize non-leak events. Focus was given to highly reflective and highly absorbent materials/conditions that are typically found near pipelines.
Techniques were developed to extract a variety of features across the several spectral bands to identify unique attributes of different types of hazardous liquid constitutions and environmental conditions as well as non-leak events. The characterization of non-leak events is crucial in significantly reducing false alarm rates. Classifiers were then trained to detect small leaks and reject non-leak events (false alarms), followed by system performance testing. The trial results of this work are discussed in this paper.