bluuebunny/crossref_metadata_2025 huggingface dataset:
Evidence of assurance enhancing the quality of voluntary environmental disclosures: an empirical analysis
Authors: Moroney Robyn , Windsor Carolyn , Aw Yong Ting
Published: April 2011

In response to investor and public concerns about harm to the environment, companies are increasingly disclosing environmental information. To enhance the quality of corporate environmental disclosures in a largely voluntary context, various stakeholders are also demanding independent assurance. This study uses a stakeholder‐agency theoretical perspective to examine whether the quality of voluntary environmental disclosures is enhanced when assured. This study also examines the difference in the quality of voluntary environmental disclosures when assurance is provided by either professional accountant assurers or private consultants. Our sample comprises listed companies voluntarily disclosing environmental information in stand‐alone reports, annual reports, and websites. We use an index based upon the Global Reporting Initiative (GRI) to measure the quality of company environmental reporting. Results of this matched pairs study show that the quality of voluntary environmental disclosures scores significantly higher for assured companies than unassured companies. For assured companies, the quality is no different when assured by accountants or consultants. Additional analysis provides preliminary evidence that experience improves the quality of environmental disclosures.
Resource use efficiency under self‐selectivity: the case of Bangladeshi rice producers
Authors: Rahman Sanzidur
Published: April 2011

The paper jointly evaluates the determinants of switching to modern rice and its productivity while allowing for production inefficiency at the level of individual producers. Model diagnostics reveal that serious selection bias exists, justifying the use of a sample selection framework in stochastic frontier models. Results revealed that modern variety selection decisions are influenced positively by the availability of irrigation and gross return from rice and negatively by a rise in the relative wage of labour. Adoption of modern rice is higher in underdeveloped regions. Seasonality and geography/location does matter in adoption decisions. Stochastic production frontier results reveal that land, labour and irrigation are the significant determinants of modern rice productivity. Decreasing returns to scale prevail in modern rice production. The mean level of technical efficiency (MTE) is estimated at 0.82. Results also demonstrate that the conventional stochastic frontier model significantly overestimates inefficiency by three points (MTE = 0.79). Policy implications include measures to increase access to irrigation, tenurial reform and keeping rice prices high to boost farm returns and offset the impact of a rise in the labour wage which will synergistically increase the adoption of modern rice as well as farm productivity.
A Multilevel Modelling Approach to Investigating the Predictive Validity of Editorial Decisions: Do the Editors of a High Profile Journal Select Manuscripts that are Highly Cited After Publication?
Authors: Bornmann Lutz , Mutz Rüdiger , Marx Werner , Schier Hermann , Daniel Hans-Dieter
Published: April 2011

Scientific journals must deal with the following questions concerning the predictive validity of editorial decisions. Is the best scientific work selected from submitted manuscripts? Does selection of the best manuscripts also mean selecting papers that after publication show top citation performance within their fields? Taking the journal Angewandte Chemie International Edition as an example, this study proposes a new methodology for investigating whether manuscripts that are most worthy of publication are in fact selected validly. First, the influence on citation of the accepted and rejected but then published elsewhere manuscripts was appraised on the basis of percentile impact classes scaled in a subfield of chemistry and, second, the association between the decisions on selection and the influence on citation of the manuscripts was determined by using a multilevel logistic regression for ordinal categories. This approach has many advantages over methodologies that were used in previous research studies on the predictive validity of editorial selection decisions.
Small Area Estimation Using a Reweighting Algorithm
Authors: Tanton Robert , Vidyattama Yogi , Nepal Binod , McNamara Justine
Published: April 2011

The paper describes a method of small area estimation which uses a reweighting algorithm to reweight survey data to a number of known totals (benchmarks) for small areas. The method has so far been used to estimate small area poverty rates and housing stress. The method gives poverty rates for small areas that are similar to those available from the 2006 Australian census, when the same definition of poverty was used. Various methods of validating the poverty rates have been used, including aggregating the poverty rates to a larger area and comparing them with official Australian Bureau of Statistics estimates from a survey, and applying the spatial microsimulation to larger areas and comparing with official Australian Bureau of Statistics survey results. Both these tests show that the estimates are comparable and fairly robust for most states in Australia.
Governing as New Labour: An Inside Account of the Blair and Brown Years
Authors: Diamond Patrick
Published: April 2011

The experience of governing at the strategic centre of the UK political system raises many important questions about the philosophy of public management and delivery, and the scope and scale of the British state. This article sheds light on those debates by offering an inside account of government at the centre during the Blair and Brown years, albeit from a particular ontological standpoint given the author's role as a Special Adviser in the Prime Minister's Policy Unit. Among the most insistent themes is the gap that so often opens up between the intentions of those in 10 Downing Street and Whitehall, and the reality of what actually happens on the ground. The drive to expand the strategic centre during the New Labour era was intended not just to improve the performance of government, but to change the nature of British society. There were, nonetheless, many unintended consequences and outcomes that resulted from New Labour's governance and Whitehall reforms.
Labour's New Labour Legacy: Politics after Blair and Brown
Authors: Heffernan Richard
Published: April 2011

The broad consequences of New Labour were that it won Labour three elections and put the party in government for thirteen years. Its most immediate legacies are twofold: first, the faltering economy and the sovereign debt crisis bequeathed to its successor; second, the electoral, ideational and organisational problems Labour itself has to face. The Blair and Brown governments never radically reformed the Thatcherite economic settlement but were, in time, incrementally to rework the economic policy they inherited. Change amid continuity was present in Labour's use of the proceeds of market-driven economic growth to radically increase investment in the public services and expand the welfare state. New Labour, in the wider political context, partially reformed the institutional environment in which politics is enacted; it played some part in helping the Conservative party educate itself on social questions; and helped alter the form and function of the modern political party. Closer to home, New Labour changed the Labour party forever.
The New British Policy Style: From a British to a Scottish Political Tradition?
Authors: Cairney Paul
Published: April 2011

The new context of coalition government and the ‘Big Society’ suggests that the UK government is moving towards a style of politics followed successfully in Scotland, extending a partnership approach from national to local forms of government. Yet the two arenas have never been as far apart as is commonly imagined. The majoritarian (UK) and consensus (Scottish) labels are misleading. British politics is not as exceptional as it is often made out to be, while Scottish politics retains many elements of its British counterpart. This article assesses the state of British politics in this light. It sets out a counter-exceptionalism thesis based on the theory and evidence from public policy. It then summarises the post-devolution evidence, producing insights on the British policy style when compared to the ‘new politics’ in Scotland.
Diversity of predaceous arthropods in the almond tree canopy in Northeastern Portugal: A methodological approach
Authors: BENHADI‐MARIN Jacinto , PEREIRA José A. , BARRIENTOS José A. , BENTO Albino , SANTOS Sónia A. P.
Published: April 2011

The almond tree is an economically important crop in Mediterranean regions. However, knowledge about the biodiversity of natural enemies that may be useful as biocontrol agents is scarce. The objectives of this work were: (i) to study the diversity of predaceous arthropods; and (ii) to establish a suitable sampling protocol for arthropods of the almond tree canopy. Between April and October of 2007 and 2008, 25 randomly selected trees were sampled in an organic almond grove located in the north‐east of Portugal using the beating technique. The specimens collected were counted and identified and the sampling protocol was established by using the accumulation curves and the seasonal richness peaks of the most abundant groups of natural enemies. A total of 1856 and 1301 arthropods were captured, respectively, in 2007 and 2008, where Araneae, Coccinellidae and Formicidae were the most abundant groups. A total of 14 families and 29 species of spiders were identified as Linyphiidae, Philodromidae, Thomisidae, Araneidae and Oxyopidae, the five most abundant families in both years. In the Coccinellidae and Formicidae communities 15 and 13 species were identified, respectively. According to taxa accumulation curves, the minimum sampling effort that provided a reliable picture of the biodiversity was established in 11 samples. Moreover, considering the seasonal richness distribution, it would be advisable to concentrate the sampling period from the beginning of July to the harvesting of almonds. This protocol might generate accurate replicate samples to estimate species richness when the effect of agricultural management is studied.
Awareness and Perceptions of the Risks of Exposure to Indoor Radon: A Population‐Based Approach to Evaluate a Radon Awareness and Testing Campaign in England and Wales
Authors: Poortinga Wouter , Bronstering Karin , Lannon Simon
Published: April 2011

The current study aimed to evaluate the locally directed radon roll‐out program that was conducted between 2001 and 2005 in England and Wales to increase radon awareness and testing rates. A representative sample of 1,578 residents aged 16 and older were interviewed who lived in radon‐affected areas of 15 local authorities in England and Wales that were eligible for participation in the program. The study systematically sampled across participating and nonparticipating local authorities, “actionable” and “nonactionable” radon‐affected areas, and geographic regions with different campaign histories (Wales, Southwest England, and the rest of England). As a multistage sampling strategy was used, the data were analyzed from a multilevel perspective. This study found that participants living in participating local authorities had higher levels of awareness and were more likely to have tested their home for radon than participants living in nonparticipating local authorities. Similar results were found for participants living in “actionable” areas as compared to those living in “nonactionable” radon‐affected areas. The study further found that radon awareness and testing rates were the highest in Southwest England and the lowest in Wales. This study suggests that the radon roll‐out program has been effective in raising awareness and testing rates, and that ongoing domestic radon campaigns in Southwest England may have raised radon awareness and testing in these areas, showing important reinforcement effects of multiple risk communication campaigns.
Neurocognition in bulimic eating disorders: a systematic review
Authors: Van den Eynde F. , Guillaume S. , Broadbent H. , Stahl D. , Campbell I. C. , Schmidt U. , Tchanturia K.
Published: April 2011

Van den Eynde F, Guillaume S, Broadbent H, Stahl D, Campbell IC, Schmidt U, Tchanturia K. Neurocognition in bulimic eating disorders: a systematic review.

Objective:  The aim of this study was to review the literature on neurocognition comparing people with a bulimic eating disorder in the acute phase of the illness with healthy controls (HC).

Method:  The review follows the PRISMA (preferred reporting items for systematic reviews and meta‐analysis) statement guidelines. Three databases (Medline, Web of Science, and Scopus) were searched combining the search terms ‘bulimic disorder’, ‘bulimia nervosa (BN)’, ‘binge‐eating disorder (BED)’ with terms referring to cognitive domains (e.g. ‘executive functions’).

Results:  Thirty‐seven studies on people with BN and four on people with BED were selected for review. Overall, sample sizes were relatively small [bulimic disorders: median and range 22 (12–83); HC: 27 (13–172)]. The diversity in methodology precluded a meta‐analytical approach. People with a bulimic disorder did not present with a clear neurocognitive profile. Inclusion of salient, disorder‐related stimuli (e.g. body weight/shape words) in the neurocognitive paradigms tended to generate differences between people with a bulimic disorder and HC.

Conclusion:  Neurocognition in bulimic eating disorders is under researched, and the available evidence is inconclusive. This review outlines strategies for further research in this area.
Quantitative Proteomics of Yeast Post‐Golgi Vesicles Reveals a Discriminating Role for Sro7p in Protein Secretion
Authors: Forsmark Annabelle , Rossi Guendalina , Wadskog Ingrid , Brennwald Patrick , Warringer Jonas , Adler Lennart
Published: April 2011

We here report the first comparative proteomics of purified yeast post‐Golgi vesicles (PGVs). Vesicle samples isolated from PGV‐accumulating sec6‐4 mutants were treated with isobaric tags (iTRAQ) for subsequent quantitative tandem mass spectrometric analysis of protein content. After background subtraction, a total of 66 vesicle‐associated proteins were identified, including known or assumed vesicle residents as well as a fraction not previously known to be PGV associated. Vesicles isolated from cells lacking the polarity protein Sro7p contained essentially the same catalogue of proteins but showed a reduced content of a subset of cargo proteins, in agreement with a previously shown selective role for Sro7p in cargo sorting.
Erectile Dysfunction is Not a Mirror of Endothelial Dysfunction in HIV-Infected Patients
Authors: Guaraldi Giovanni , Beggi Mattia , Zona Stefano , Luzi Kety , Orlando Gabriella , Carli Federica , Ligabue Guido , Rochira Vincenzo , Rossi Rosario , Modena Maria Grazia , Bouloux Pierre
Published: April 2011

Introduction

The penis has been compared to a barometer of endothelial health, erectile dysfunction (ED) being an early sign of endothelial dysfunction.

Aim

The aim of the study was to investigate the extent of the association between ED and endothelial dysfunction in patients with human immunodeficiency virus (HIV) infection on antiretroviral therapy.

Methods

In this observational cross-sectional study, we evaluated the prevalence and factors associated with ED in a cohort of 133 HIV-infected men.

Main Outcome Measures

The International Index of Erectile Function, ultrasound assessment of brachial artery flow mediated dilatation (FMD), and multi-slice computed tomography for coronary artery calcifications (CAC) as surrogates of endothelial dysfunction, the Adult Treatment Panel III criteria to diagnose metabolic syndrome (MS), plasma total testosterone (hypogonadism), and a visual analogue scale (VAS) of aesthetic satisfaction of the face and of the body (psychological distress associated with lipodystrophy).

Results

Thirty-nine (29.32%) patients had mild ED, 14 (10.52%) patients had moderate ED, and 26 (19.55%) patients had severe ED. Prevalence of ED ranged from 45% to 65%, respectively, in patients less than 40 and more than 60 years old. MS was present in 20 (25%) patients with ED and 13 (24%) patients without ED (P value = 0.87). Prevalence of ED neither appeared to be associated with MS as a single clinical pathological entity nor with the numbers of its diagnostic components. FMD < 7% was present in 25 (32%) patients with ED and 18 (33%) patients without ED (P value = 0.83), and CAC > 100 was present in 8 (10%) patients with ED and 5 (9%) patients without ED (P value = 0.87). A stepwise multivariable logistic regression analysis was used to find predictors of ED. Independent predictors were VAS face (odds ratio [OR] = 0.85, 95% confidence interval [CI] 0.73–0.99, P = 0.049) and age per 10 years of increase (OR = 1.73, 95% CI 1.02–2.94, P = 0.04).

Conclusions

Age constituted the most important risk factor for ED, which was related to aesthetic dissatisfaction of the face leading to negative body image perception.
The Rationale and Design of the Giant Intracranial Aneurysm Registry: A Retrospective and Prospective Study
Authors: Dengler Julius , Heuschmann Peter U. , Endres Matthias , Meyer Bernhard , Rohde Veit , Rufenacht Daniel A. , Vajkoczy Peter ,   on behalf of the Giant Intracranial Aneurysm Study Group
Published: April 2011

Aims and Hypothesis

Giant intracranial aneurysms have a poor prognosis mainly due to their high risk of rupture. Because their incidence is low, clinical trial evidence for adequate treatment is lacking. The Giant Intracranial Aneurysm Registry is designed to document current treatment strategies in giant aneurysm care and to monitor the course of the disease over five-years. It aims to evaluate the hypothesis that all three possible branches of therapy (conservative/endovascular/surgical) lead to equal rupture rates.

Design

The Giant Intracranial Aneurysm Registry is an interdisciplinary multicenter observational study. Each center recruits patients diagnosed with a giant intracranial aneurysm both prospectively and retrospectively. Primary outcome will be the aneurysm rupture rate at five-years of follow-up.

Study Outcome

Patient enrollment has begun at 20 neurovascular centers throughout Germany, with 19 further centers applying for local ethics approval to take part in the study. The first nine months are designed as a pilot phase followed by the integration of study centers throughout the EU and the initiation of separate sub-studies.

Discussion

Giant intracranial aneurysms have often been ignored or marginalized due to their low incidence. The Giant Intracranial Aneurysm Registry aims to lead to a better understanding of these complex lesions and to serve as a basis for the development of future clinical studies.
CFD Tool for Assessment of the Reactor Pressure Vessel Integrity in Pressure Thermal Shock Conditions: Influence of Turbulence Model and Mesh Refinement on the Vessel Thermal Loading During PTS Transient
Authors: Martin A. , Benhamadouche S. , Bezdikian G. , Beaud F. , Lestang F.
Published: April 2011

Integrity evaluation methods for nuclear reactor pressure vessels (RPVs) under pressurized thermal shock (PTS) loading are applied by French Utility. They are based on the analysis of the behavior of relatively shallow cracks under loading PTS conditions due to the emergency cooling during small break loss of coolant accident (SBLOCA) transients. This paper presents the research and development program started at EDF on the computational fluid dynamics (CFD) determination of the cooling phenomena of a PWR vessel during a pressurized thermal shock. The numerical results are obtained with the thermal-hydraulic tool Code̱Saturne, in combination with the thermal-solid code SYRTHES to take into account the coupled effect of heat transfer between the fluid flow and the vessel. Based on the global and local thermal-hydraulic analysis of a small break loss of coolant accident transient, this paper presents mainly a parametric study that helps to understand the main phenomena that can lead to better estimating the margin factors. The geometry studied represents a third of a PWR pressure vessel, and the configuration investigated is related to the injection of cold water in the vessel during a SBLOCA transient. Conservative initial and boundary conditions for the CFD calculation are derived from the global thermal-hydraulic analysis. Both the fluid behavior and its impact on the solid part formed by cladding and base metal are considered. The main purpose of the numerical thermal-hydraulic studies is to accurately estimate the distribution of fluid temperature in the downcomer and the heat transfer coefficients on the inner RPV surface for a fracture mechanics computation, which will subsequently assess the associated RPV safety margin factors.
A Study on Engine Health Monitoring in the Frequency Domain
Authors: Borguet S. , Henriksson M. , McKelvey T. , Léonard O.
Published: April 2011

Most of the techniques developed to date for module performance analysis rely on steady-state measurements from a single operating point to evaluate the level of deterioration of an engine. One of the major difficulties associated with this estimation problem comes from its underdetermined nature. It results from the fact that the number of health parameters exceeds the number of available sensors. Among the panel of remedies to this issue, a few authors have investigated the potential of using data collected during a transient operation of the engine. A major outcome of these studies is an improvement in the assessed health condition. The present study proposes a framework that formalizes this observation for a given class of input signals. The analysis is performed in the frequency domain, following the lines of system identification theory. More specifically, the mean-squared estimation error is shown to drastically decrease when using transient input signals. This study is conducted with an engine model representative of a commercial turbofan.
Comparison of LES of Steady Transitional Flow in an Idealized Stenosed Axisymmetric Artery Model With a RANS Transitional Model
Authors: Tan F. P. P. , Wood N. B. , Tabor G. , Xu X. Y.
Published: April 2011

In this study, two different turbulence methodologies are investigated to predict transitional flow in a 75% stenosed axisymmetric experimental arterial model and in a slightly modified version of the model with an eccentric stenosis. Large eddy simulation (LES) and Reynolds-averaged Navier–Stokes (RANS) methods were applied; in the LES simulations eddy viscosity subgrid-scale models were employed (basic and dynamic Smagorinsky) while the RANS method involved the correlation-based transitional version of the hybrid k-ε/k-ω flow model. The RANS simulations used 410,000 and 820,000 element meshes for the axisymmetric and eccentric stenoses, respectively, with y+ less than 2 viscous wall units for the boundary elements, while the LES used 1,200,000 elements with y+ less than 1. Implicit filtering was used for LES, giving an overlap between the resolved and modeled eddies, ensuring accurate treatment of near wall turbulence structures. Flow analysis was carried out in terms of vorticity and eddy viscosity magnitudes, velocity, and turbulence intensity profiles and the results were compared both with established experimental data and with available direct numerical simulations (DNSs) from the literature. The simulation results demonstrated that the dynamic Smagorinsky LES and RANS transitional model predicted fairly comparable velocity and turbulence intensity profiles with the experimental data, although the dynamic Smagorinsky model gave the best overall agreement. The present study demonstrated the power of LES methods, although they were computationally more costly, and added further evidence of the promise of the RANS transition model used here, previously tested in pulsatile flow on a similar model. Both dynamic Smagorinsky LES and the RANS model captured the complex transition phenomena under physiological Reynolds numbers in steady flow, including separation and reattachment. In this respect, LES with dynamic Smagorinsky appeared more successful than DNS in replicating the axisymmetric experimental results, although inflow conditions, which are subject to caveats, may have differed. For the eccentric stenosis, LES with Smagorinsky coefficient of 0.13 gave the closest agreement with DNS despite the known shortcomings of fixed coefficients. The relaminarization as the flow escaped the influence of the stenosis was amply demonstrated in the simulations, graphically so in the case of LES.
The Ultimate Solution: Disposal of Disused Sealed Radioactive Sources (DSRS)
Authors: Heard R. G.
Published: April 2011

The borehole disposal concept (BDC) was first presented to ICEM by Potier, J-M in 2005 [1]. This paper repeats the basics introduced by Potier and relates further developments. It also documents the history of the development of the BDC. For countries with no access to existing or planned geological disposal facilities for radioactive wastes, the only options for managing high activity or long-lived disused radioactive sources are to store them indefinitely, return them to the supplier or find an alternative method of disposal. Disused sealed radioactive sources (DSRS) pose an unacceptable radiological and security risk if not properly managed. Out of control sources have already led to many high-profile incidents or accidents. One needs only to remember the recent accident in India that occurred earlier this year. Countries without solutions in place need to consider the future management of DSRSs urgently. An on-going problem in developing countries is what to do with sources that cannot be returned to the suppliers, sources for which there is no further use, sources that have not been maintained in a working condition and sources that are no longer suitable for their intended purpose. Disposal in boreholes is intended to be simple and effective, meeting the same high standards of long-term radiological safety as any other type of radioactive waste disposal. It is believed that the BDC can be readily deployed with simple, cost-effective technologies. These are appropriate both to the relatively small amounts and activities of the wastes and the resources that can realistically be found in developing countries. The South African Nuclear Energy Corporation Ltd (Necsa) has carried out project development and demonstration activities since 1996. The project looked into the technical feasibility, safety and economic viability of BDC under the social, economic, environmental and infrastructural conditions currently prevalent in Africa. Implementation is near at hand with work being done in Ghana with support from the IAEA. Here the site selection is complete and studies are being carried out to test the site parameters for inclusion into the safety assessment.
Alpha Radioactivity Monitor Using Ionized Air Transport Technology for Large Size Uranium Waste: Part 2—Simulation Model Reinforcement for Practical Apparatus Design
Authors: Asada Takatoshi , Hirata Yosuke , Naito Susumu , Izumi Mikio , Yoshimura Yukio
Published: April 2011

In alpha radioactivity measurement using ionized air transportation (AMAT), conversion from ion currents to radioactivity accurate is required. An ion transport simulation provides ways of complementarily determining conversion factors. We have developed an ion transport simulation model. Simulation results were compared with experiments with air speeds, faster than 1 m/s, achieving good agreement. In a practical AMAT apparatus, the air-flow at the alpha source may be slower than 1 m/s, and ion loss is likely to be large. Reinforcement of the ion transport model to cover the lower air speed region is effective. Ions are generated by an alpha particle in a very thin column. Since the ion density at this temporal stage is high, the recombination loss, proportional to the square of ion density, is dominant within a few milli-seconds. The spatial and temporal scales of this columnar recombination are too small for CFD simulation. We solve an ion transport equation during the period of columnar recombination with diffusion and recombination terms and incorporated the relation between ion loss and turbulent parameters into CFD. Using this model, simulations have been done for various air speeds and targets. Those for simulation results agree with experiments, showing improvement of simulation accuracy.
Impermeable Graphite: A New Development for Embedding Radioactive Waste
Authors: Fachinger Johannes , Grosse Karl-Heinz , Seemann Richard , Hrovat Milan
Published: April 2011

The natural occurrence of graphite proves its geological stability over long time periods and therefore it could be considered as a matrix for embedding radioactive waste. However its porous structure affects the possible use of graphite as long term stable waste matrix for final disposal. Aqueous phases can penetrate the pore system and radionuclides adsorbed on the surface can be leached. Furthermore slow corrosion in aquatic phases can be induced by high irradiation dose rates in the range of 10−5 to 10−7 gm−2d−1. Therefore radiation induced corrosion process cannot be neglected in geological time scales. These problems can be solved with a graphite material with a closed pore system. A graphite composite material with an inorganic binder has been developed with a density > 99.7% of theoretical density and a negligible porosity. An initial calculation predicts that the life time of the graphite will be at least 2 orders of magnitude higher than porous graphite. This material represents a long term stable leaching resistant matrix applicable for the embedding of irradiated graphite (i-graphite). Natural graphite can be added to improve the compaction behavior and mechanical properties. Additional applications could be the embedding of other radioactive wastes in this matrix.
Advanced Remedial Methods for Metals and Radionuclides in Vadose Zone Environments
Authors: Wellman Dawn M. , Mattigod Shas V. , Hubbard Susan , Miracle Ann , Zhong Lirong , Foote Martin , Wu Yuxin , Jansik Danielle
Published: April 2011

Functionally, the methods for addressing contamination must remove and/or reduce transport or toxicity of contaminants. This problem is particularly challenging in arid environments where the vadose zone can be up to hundreds of feet thick, rendering transitional excavation methods exceedingly costly and ineffective. Delivery of remedial amendments is one of the most challenging and critical aspects for all remedy-based approaches. The conventional approach for delivery is through injection of aqueous remedial solutions. However, heterogeneous vadose zone environments present hydrologic and geochemical challenges that limit the effectiveness. Because the flow of solution infiltration is dominantly controlled by gravity and suction, injected liquid preferentially percolates through highly permeable pathways, by-passing low-permeability zones which frequently contain the majority of the contamination. Moreover, the wetting front can readily mobilize and enhance contaminant transport to underlying aquifers prior to stabilization. Development of innovative, in-situ technologies may be the only way to meet remedial action objectives and long-term stewardship goals. Shear-thinning fluids (i.e., surfactants) can be used to lower the liquid surface tension and create stabile foams, which readily penetrate low permeability zones. Although surfactant foams have been utilized for subsurface mobilization efforts in the oil and gas industry, so far, the concept of using foams as a delivery mechanism for transporting reactive remedial amendments into deep vadose zone environments to stabilize metal and long-lived radionuclide contaminants has not been explored. Foam flow can be directed by pressure gradients, rather than being dominated by gravity; and, foam delivery mechanisms limit the volume of water (< 20% vol.) required for remedy delivery and emplacement, thus mitigating contaminant mobilization. We will present the results of a numerical modeling and integrated laboratory-/intermediate-scale investigation to simulate, develop, demonstrate, and monitor (i.e. advanced geophysical techniques and advanced predictive microbial markers) foam-based delivery of remedial amendments to remediate metals and radionuclides in vadose zone environments.
The Progress and Results of a Demonstration Test of a Cavern-Type Disposal Facility
Authors: Akiyama Yoshihiro , Terada Kenji , Oda Nobuaki , Yada Tsutomu , Nakajima Takahiro
Published: April 2011

The cavern-type disposal facilities for low-level waste (LLW) with relatively high radioactivity levels mainly generated from power reactor decommissioning and for part of transuranic (TRU) waste mainly from spent fuel reprocessing are designed to be constructed in a cavern 50 to 100 meters below ground, and to employ an engineered barrier system (EBS) of a combination of bentonite and cement materials in Japan. In order to advance the feasibility study for these disposal, a government-commissioned research project named Demonstration Test of Cavern-Type Disposal Facility started in fiscal 2005, and since fiscal 2007 a full-scale mock-up test facility has been constructed under actual subsurface environment. The main objective of the test is to establish construction methodology and procedures which ensure the required quality of the EBS on-site. By fiscal 2009 some parts of the facility have been constructed, and the test has demonstrated both practicability of the construction and achievement of the quality. They are respectively taken as low-permeability of less than 5×10−13 m/s and low-diffusivity of less than 1×10−12 m2/s at the time of completion of construction. This paper covers the project outline and the test results obtained by the construction of some parts of a bentonite and cement materials.
Propagation and Interactions of Acoustic Waves in a Waveguide Attached at the Surface of Rock
Authors: Kim Jin-Seop , Lee Kyung-Soo , Kwon S. , Cho Gye-Chun
Published: April 2011

Measurements of the dynamic response of a rock mass are inevitable in the systematic long-term monitoring and the maintenance of the radioactive waste disposal repository. With this point of view, AE (acoustic emission) detection is considered to be a promising technique for monitoring the in-situ performance of a rock mass. In this study, the propagation and interactions of guided acoustic waves in a waveguide connector, which is required in an in-situ application of an AE monitoring system were investigated and the coupling methods of a waveguide to the surface of rock mass were compared. The changes in acoustic wave amplitude, time delay, frequency variation, and system transfer function were measured between the waveguide and a rock sample. Subsequently the waveguide coupling conditions filled with epoxy were compared with a mechanical type of coupling for the validity of field application. The results derived from this study can be valuable information for the quantitative analysis of signal processing in AE source localization and the degree of crack damage in a radioactive waste repository.
Frequency Dependence of Fatigue and Corrosion Fatigue Crack Growth Rate
Authors: Marvasti Mohammad Hassan , Chen Weixing , Kania Richard , Worthingham Robert , Van Boven Greg
Published: April 2011

Corrosion fatigue and fatigue crack growth in air tests were comparatively conducted on an X52 pipelines steel. Fatigue crack growth rates in air were lower than corrosion fatigue crack growth rates due to the absence of hydrogen and mechanical dormancy arisen from low temperature creep at low cyclic frequencies. Mechanical dormancy can commonly occur during operation of both oil and gas pipelines. Crack growth in near neutral pH environments can be well rationalized by a combined loading factor, (ΔK)2Kmax/fα, which reflects the synergistic interaction between the mechanical driving force and the hydrogen effects. Hydrogen plays a decisive role in terms of crack growth in pipelines steels exposed to near neutral pH environments.
Burst Limit State Reliability for Fiber-Wrapped Steel Pipe
Authors: Dann Markus R. , Maes Marc A. , Salama Mamdouh M.
Published: April 2011

Dry fiber augmented steel technology pipelines (FAST-Pipe™) have recently been the object of considerable attention due to both cost and availability advantages (as opposed to high strength steels) and due to their promising use in future Arctic pipeline solutions. The present paper focuses on the development and the use of a burst limit state for such fiber wrapped pipes. It describes in detail a probabilistic mechanical burst limit state model for FAST. The model is based on a large strain Cauchy stress formulation using Stewart’s isotropic strain hardening for steel pipe which is hoop-constrained by elastic fiber wrapping. The limit state model is used for a reliability comparison between FAST-Pipes and traditional pure steel pipes as well as for a risk-based equivalence between different design solutions.
Analysis of Stresses on Buried Pipeline Subjected to Landslide Based on Numerical Simulation and Regression Analysis
Authors: Han Bing , Hao Jianbin , Jing Hongyuan , Liu Jianping , Wu Zhangzhong
Published: April 2011

The integrity of oil and gas pipelines is seriously impacted by landslides in tough terrain in western China. The quantitative assessment technology is an effective method for pipelines risk management under threat of geohazard. In order to establish the vulnerability assessment indexes system of pipelines subjected to landslides, the numerical simulation based on the finite element method is adopted to study the pipeline axial stresses. There are five kinds of calculation schemes considered by changing the geometrical sizes and inclination angles of landslide, the pipeline length passing through landslide and buried depth of pipeline, and the axial stresses and bending moments of pipeline can be obtained by means of numerical simulation for different calculation conditions under the every kind of scheme. In the study, regression analysis method is used to derive the axial stress equation of pipeline from calculation results of numerical simulation by taking into consideration the above five indexes. The feasibility and practicality of this equation are verified by the given example of a pipeline passing through a certain landslide in southwest China. The comparison analysis between the monitoring data and calculation results shows that the calculation values agree well with the monitoring data of pipeline axial stresses.
Monitoring of Natural Gas Pipeline Leaks
Authors: Yu Dongliang , Wang Likun , Xu Bin , Wang Hongchao , Xiong Min , Tan Dongjie
Published: April 2011

Pipe is a very important tool for long-distance transportation of nature gas. In the long-term running, there will be inevitably an appearance of a rupture, leak or damage usually caused by manmade event or by nature disaster. Leaks may generate dangerous clouds of gas escaping from the high-pressure pipe and produce serious incidences involving fire and explosion endangering the life and property safety of people in and around the area. Monitoring of natural gas pipeline leaks will timely find out and locate these dangerous occurrences and reduce loss. Within the leak monitoring, the core contents are the accurate location of leaks as well as the rapid identification of different signal sources reducing false alarm ratio. Once a leak occurs, the supersonic jet of escaping gas can generate a non-linear & chaotic negative pressure wave signal based on static pressure measurement and an acoustic signal based on dynamic pressure measurement [1]. By properly interpreting these two kinds of signals together, it is possible to detect and locate the leak along the pipe. However, useful signals usually mix in the powerful backdrop signals and noises. In order to resolve the problem, the wavelet packet decomposition technique [2] is used to reduce the noises and get the feature signals of negative pressure wave and acoustic wave. Furthermore, a lot of different condition regulating signals for instance compressor start-stop, valve adjusting and gas turbulence can interfere with the accurate identification of leaks and result in false alarm. It is quite required to classify these similar signals. Thus, BP neural network [3] is used to quickly recognize the different pressure fluctuation signals. Finally, an integrated system developed by LabView is introduced to timely monitor the operation condition and locate the leak. Field tests indicate this system using negative pressure wave method, acoustic wave method, wavelet packet decomposition technique as well as BP network has a good effect.
Behaviour of Externally Corroded Pipelines Under Axial Deformation
Authors: Dewanbabee Halima , Silva Jorge , Rafi Abu , Das Sreekanta
Published: April 2011

Corrosion is a major cause for buried gas pipeline failure. Current design guidelines are limited to pressure loading for assessing a corroded pipeline’s integrity. A few studies were conducted by other researchers to determine the remaining bending or pressure strength of the corroded pipelines under combined loading. However, no study was conducted to determine the axial compressive strength and ductility of the corroded pipelines although these could be the major cause of the pipeline failure. Therefore, the current study was undertaken to understand how the corrosion geometry influences the structural behavior of externally corroded line pipes when they are subjected to axial deformation and internal pressure. Three full-scale tests have been completed and it was found that the pipe that was used in this study is highly ductile and do not rupture under monotonically increasing axial deformation. This paper discusses test set up, test procedure, and results obtained from these tests.
Oil/Gas Pipeline Simulation Using a Segregated Method
Authors: Miao Qing , Xu Bo
Published: April 2011

The coupled method is usually used to solve the non-linear governing equations in oil/gas pipeline simulation applications, particularly for compressible fluid flow. In this paper, a segregated method with mesh refinement is proposed. The segregated method presents the advantage of the reduced computational memory and CPU time cost. In addition it also improves the convergence for the reason that the condition number is decreased as the matrix size is significantly reduced compared with the coupled method. In the presented method, a coarse mesh is adopted firstly. When the solution point for the nodes of this mesh is close enough to the optimal solution point, indicated by a certain criteria, a refine mesh is constructed by the solver thereafter. The value on the computing nodes for the refine mesh is computed by interpolation based on the previous solution point. Then the final solution for the refine mesh is obtained by the new segregated solver. Typical applications for oil/gas pipeline simulation are given. Results obtained by the method are compared with those obtained by using a “standard” software package to validate its accuracy. Results show that the average error between those solution obtained by different solvers is less than 1.0%. The efficiency of the new method is compared with the efficiency of a traditional coupled method. Numerical tests show that the method saves more than 50% of computational cost and the matrix size is reduced significantly.
Activated Carbon Systems for Capturing Blowdown Hydrocarbons From Pipeline Facilities
Authors: Botros K. K. , Crowe J. S. , Sloof B.
Published: April 2011

Adsorption of hydrocarbons by activated carbon (AC) has been the subject of recent development and advancement. One of the applications of this technology is in the capture of planned blowdown gases for the purpose of reducing greenhouse gas emissions. A conceptual design of a large AC-based adsorbed natural gas (ANG) storage system has been configured to capture at least 35–40% of the blowdown gases released from high pressure (60 bar) facilities. This design consists of 46 × 14″ diameter pipe modules mounted on a trailer. A smaller ANG unit consisting of a standard gas cylinder or a pressure vessel filled with AC has also been designed to capture blowdown gases from small-volume systems such as compressor casings. The performance of both storage units has been evaluated numerically, and important design parameters are quantified for a given range of operating conditions. Results of this evaluation and future work are highlighted.
Comparative Study on the Transportation Charge of Crude Oil Between Pipeline and Railway in China
Authors: Xing Xiaokai , Wu Changchun , Liu Bing
Published: April 2011

Economic contrast of crude oil transportation charge between pipeline and railway affects the pipe network and rail network planning of the area, and the relevant studies have not been seen in literature. On the basis of evaluation methods and parameter and other relevant provisions of construction projects regulated by China National Petroleum Corporation (CNPC), the paper conducted a comparative study on the transportation charge of crude oil by the pipeline and railway. The transportation charge by the pipeline was calculated based on the minimum attractive rate of return (MARR). The results show that transportation charge is 0.06∼0.14 CNY/ton·km and will decrease with the size of the diameter of the pipe and increase with the distance of the transportation. The study on railway transportation charge shows that the charge is 0.13∼0.25 CNY/ton·km, which will decrease with the distance but has no relation with the amount of crude oil. The thicker the diameter of pipe, the lower the charge is by the pipe, which is relevant to the loading rate. When the loading rate is 38–72%, the transportation charge by the two ways are almost the same.
Leak Detection for City Gas Pipelines Based on Instantaneous Energy Distribution Characteristics
Authors: Chen Zhigang
Published: April 2011

Because of the smallness of flux and low of pressure it is difficult to judge the characteristic signal when leak occurs. In this paper, a new instantaneous energy (IE) distribution characteristics extraction method based on Hilbert-Huang transformation (HHT) was presented and it was used to recognize different states in pipelines, such as, normal state, valve operating, compressor operating and leak. Firstly, the physical relationship between instantaneous energy and structural state variation of a system was analyzed theoretically. With HHT, the instantaneous energy distribution feature of an unstable pressure signal was obtained, according to the relative contribution method of the instantaneous energy, its noise was eliminated. In order to judge the leak the typical character of the instantaneous energy of pressure in the input and output ends was discussed using correlative analysis. The experimental results showed that this method is effective.
Research on the Fatigue Character of ERW Pipe Welded Seam and Fatigue Life Assessment Method
Authors: Zhang Guangli , Luo Jinheng , Zhao Xinwei , Zhang Hua , Zhang Liang , Zhang Yi
Published: April 2011

The fatigue character of electric resistance weld (ERW) seams in API X65 grade line pipe steel at the stress ratio of 0.1 and 0.6 have been investigated. Repeated loading was applied to compact tension specimen, and the fatigue crack propagation rate and threshold of X65 ERW pipe seam are tested using high-frequency fatigue testing machine. Radiographic inspection has shown that the crack caused by the cold welding is the main weld defect in the ERW pipe. Based on the failure assessment diagram (FAD) recommended in the API 579-2007 and the Miner’s linear cumulative damage model, considering the influence of stress ratio to the fatigue life, the fatigue life assessment method for the ERW pipe containing seam defects is established.