Academic literature on the topic 'Sand limit state'
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Journal articles on the topic "Sand limit state"
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I.P, Ukwoma,, Akpokodje, E.G., and Nwankwoala, H.O. "TEXTURE AND CEMENT STABILIZATION OF DREDGED SAND USED FOR OGBIA – NEMBE ROAD, BAYELSA STATE, NIGERIA." Engineering Heritage Journal 6, no. 1 (2022): 06–13. http://dx.doi.org/10.26480/gwk.01.2022.06.13.
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This paper is aimed at determining the texture, compaction, and cement stabilization properties of the dredged sand used in the Ogbia-Nembe road construction in Bayelsa State, Nigeria. Both field and laboratory studies were undertaken. Results from the laboratory tests revealed the various properties as follows: moisture content (41.3 – 58.2%), Liquid limit (45.5 – 50.5%), Plastic limit (26.2 – 33.7%), Plasticity Index (16.8 – 20.6%), Cu (2,15 – 3.16), Optimum moisture content (OMC) and Maximum dry densities (MDD) for the dredged sands are (9.2 – 9.4) and (1600 – 1620kN/m3 respectively. The OMC, MDD and California bearing ratio (CBR) of the sand-cement mixture are 10.2 – 12.6%, 1830 – 1880kN/m3, 177 -313% and 1140 -2905kN/m2 respectively. The dredged sands are classified as A-3 according to the AASHO classification system. However, the average MDD of the dredged sand is 1620kN/m3 which is below the Federal Ministry of Works (FMW) specification for pavement construction, therefore the need for stabilization. Stabilization of the sand with 6% – 10% cement increased the MDD, CBR, UCS to 1880kN/m3, 313% and 2905kN/m2, respectively. The results of this study revealed that the minimum percentage of cement required to stabilize the dredged sand used for the construction of the road is 6%. Also, particle size of cohesionless soil affects the density and sand-cement stabilization is more economical than paying for additional maintenance cost if the pavement fails. This study also revealed that increasing the percentage of cement of a sample does make the soil brittle as well as increases the strength of the material/soil.
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Sun, Dongning, Xin Liu, Yuhao Cao, Junjie Gong, and Baoning Hong. "Determination of Cost-Effective Sand Mixing Ratio for Improvement of High Liquid Limit Soil Based on Fuzzy Comprehensive Evaluation." IOP Conference Series: Materials Science and Engineering 1203, no. 3 (November 1, 2021): 032060. http://dx.doi.org/10.1088/1757-899x/1203/3/032060.
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Abstract In order to save soil resources and increase the utilization range of high liquid limit soil, the high liquid limit soil was improved by mixing sand, and the cost-effective sand mixing ratio was determined with the help of fuzzy comprehensive evaluation method. It is shown that the sand-mixing improvement method can significantly reduce the liquid limit and plasticity index of high liquid limit soil, and increase its value of California bearing ratio to meet the property requirements for embankment filling. The fuzzy comprehensive evaluation results show that the improvement effect and cost of sand-mixed high liquid limit soil reach a comprehensive optimal state when the sand mixing ratio is 20%.
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Ikoko, N. L. A., M. A. Briggs-Kamara, F. B. Sigalo, A. R. C. Amakiri, and H. N. Ude. "Spatial Distribution of Radiometric and Dosimetric Parameters in Soil Samples from Selected Areas in Bayelsa State, Nigeria." Journal of Applied Sciences and Environmental Management 26, no. 5 (May 31, 2022): 975–81. http://dx.doi.org/10.4314/jasem.v26i5.27.
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Radiation from radioactive materials/radionuclides in the environment enhanced by anthropogenic activities is presently of a great concern globally. The objective of this study is to determine the radiometric and dosimetric parameters from soil samples collected randomly from the study area of Bayelsa State, Nigeria. The samples were prepared using standard methods and analyzed with a high resolution Hyperpure Germanium Detector configuration (HPGe). The results showed the clay samples to have higher activity concentration to the sands samples with activity concentration of clay samples ranging between 68.99±9.05 –189, 42±21.11Bq/kg and the sand samples with activity concentration range of 17.95±5.87 – 38.59±7.43Bq/kg. The activity concentration spatial distribution map in clay lithologies showed 2 peak values trending north-west, while the sand lithology showed a single peak central distribution. The result also showed the values of the absorbed doses with the 8 clay samples values ranging between 59.09 - 155.25nGy/h and sand samples values between 17.90 – 33.92nGy/h. The spatial distribution of the dose showed 2 peak central distribution in clay samples and north-east trending distribution of high peak values for samples with sand lithologies. In addition, the results showed an effective absorbed dose of range of 0.235-0.0616mSv/y for samples with clay lithology and 0.0071-0.0135mSv/y for samples with sand lithology The activity concentration of all the samples studied are below the 1000Bq/kg international reference limit for Radium 226, Thorium 232, uranium 238 and 10,000Bq/kg for potassium 40. The absorbed dose rate and annual effective absorbed dose are also below the international reference limits published by ICRP, 2007 and UNSCEAR, 2000 publications. Also, effective activity maximum limit of 370Bq/kg for input raw materials for public building is not exceeded.
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Łucarz, M. "State of Spent Molding Sands in the Mold Large-Size Cast." Archives of Foundry Engineering 16, no. 4 (December 1, 2016): 69–74. http://dx.doi.org/10.1515/afe-2016-0086.
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Abstract The results of investigations of spent moulding sands taken from the mould at various distances from the surface of the produced casting, are presented in the paper. The casting mould was made with an application of the cooling system of the metal core in order to increase the cooling rate of the ladle casting. As temperature measurements in the mould indicated the heat flow from the metal did not create conditions for the complete burning of a moulding sand. The analysis was performed to find out changes of spent moulding sands caused by degradation and destruction processes of organic binders. Conditions occurring in the casting mould were discussed on the bases of testing: ignition losses, dusts contents, pH reactions and the surface morphology of the moulding sand samples. Factors limiting the effective mould degassing were pointed out. Operations, possible for realization, which can limit the reasons of a periodical occurrence of increased amounts of casting defects due to changing gas evolution rates being the result of the technological process, were also indicated.
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Vicedo, Jorge Soriano, Javier García Barba, Jorge Luengo Frades, and Vicente Negro Valdecantos. "Scale Tests to Estimate Penetration Force and Stress State of the Silica Sand in Windfarm Foundations." Energies 14, no. 18 (September 17, 2021): 5904. http://dx.doi.org/10.3390/en14185904.
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The analysis of the soil behavior when the pile is driving into the seabed in offshore wind platforms is one of the major problems associated with this new form of clean energy generation. At present, there are no scaled studies carried out analyzing the mechanical and deformational behavior of both the material of the pile supporting the engine (large steel hollow piles with a diameter of 8 m and a thickness of 15–20 cm) and the soil where the pile is driven. Usually, these elements are installed on sands with a very small grain size displaced from the limits of dry–wet beach (water limit) toward the offshore limits, which prevents them from returning to their previous location in a natural way. This paper presents results obtained from scale tests in a steel pool to analyze the behavior of the sand where the piles were installed. First, the California Bearing Ratio (CBR) test was carried out to estimate the soil behavior in similar conditions to the steel pool. The scale tests consisted of the penetration of the steel tube into the sand using a hydraulic press. The objective was to compare the results for three tubes with different diameters, three different speeds, and two kinds of ending on the extreme of the tested element.
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Kechkar, Chiraz, Leila Kherraf, Assia Abdelouahid, and Houria Hebhoub. "THE COMPARATIVE STUDY OF THE PERFORMANCE OF CONCRETE MADE FROM RECYCLED SAND." Stavební obzor - Civil Engineering Journal 31, no. 3 (October 30, 2022): 415–26. http://dx.doi.org/10.14311/cej.2022.03.0031.
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The main objective of this study of research is to initiate and develop a comparative study of fresh and hardened properties of concretes made from recycled sand from three types of waste: marble waste, tiling waste and cinder block waste. And this, in the intention of contributing to the world effort relating to the preserve of natural aggregate resources and limit landfill to the ultimate waste thresholds.
To do this, in the composition of a current concrete with a water / cement ratio equal to 0.55, an equivalent volume of sand from the three wastes respectively replaced a volume of 15% of the ordinary sand. The properties in the fresh state: workability, air content and density and in the hardened state: compressive strength, Flexural tensile strength, compressive strength determined with non-destructive tests, water absorption by immersion, absorption by capillarity and chloride penetration of the various concretes produced are analyzed, and compared to those of the control concrete.
The results obtained show that the concretes containing the waste sands have acceptable characteristics. However, tiling waste sand performs better than the other two recycled sands.
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Uzielli, Marco, and Paul W. Mayne. "Serviceability limit state CPT-based design for vertically loaded shallow footings on sand." Geomechanics and Geoengineering 6, no. 2 (June 2011): 91–107. http://dx.doi.org/10.1080/17486025.2010.531146.
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T. V, Nwosu, Nwaiwu C.J, and Egboka N.T. "ANALYSIS OF WATER QUALITY DETERIORATION IN NWORIE RIVER, OWERRI- IMO STATE, SOUTHEAST, NIGERIA." Journal CleanWAS 5, no. 2 (July 1, 2021): 58–61. http://dx.doi.org/10.26480/jcleanwas.02.2021.58.61.
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Due to indiscriminate activities of man through sand excavation, sand mining and illegal waste disposal within the watershed the study evaluated the effect of these activities on selected water quality parameters of Nworie River in Owerri -Imo State, Southeast Nigeria. The study area was divided into Upstream, Midstream and downstream. The river was sampled and the raw data from water sampling were subjected to laboratory analysis; results obtained were matched with standards. The results showed that the average pH of the river was 7.4; upstream and midstream had higher pH values than the downstream with low pH and these were within the permissible limit. Biological oxygen Demand (BOD) of the river were 75mg/l, 60mg/l and 56mg/l at the Upstream, Midstream and downstream with an average value of 64 mg/l . The river had a mean turbidity value of 76NTU and mean Total Dissolved solids (TDS) value of 272mg/l which were above the permissible limit. Calcium (Ca2+) did not exceed the standard limit while magnesium exceeded the standard limit by 68% at the Upstream. Nworie river had mean water conductivity value of 93S/cm; water conductivity at the Midstream and downstream were within the permissible limits while the Upstream had 6% increase above the acceptable limit. It was observed from this study that Nworie river exhibited three different colours of light-green, dark-green and brownish-muddy colour respectively at the Upstream, Midstream and Downstream which could be attributed to the level of erosional deposits and sediment loads from the degraded watershed. Further degradation of the watershed should be avoided by practising good soil conservation measures, ensuring that indiscriminate activities of inhabitants of the area are stopped and since environmental balance, land degradation, water management and food security are strongly linked, each must be addressed in the context of the other to have a measurable impact to the society.
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Matvienko, Maxim, Vladimir Dyba, and Julia Matvienko. "Combined soil foundation analysis based on ultimate limit state." E3S Web of Conferences 371 (2023): 02023. http://dx.doi.org/10.1051/e3sconf/202337102023.
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The paper defines an updated method for “soil – reinforced concrete foundation” calculation that takes into account their mutual interaction. In this method, both the foundation structure and the footing structure are represented by a rigid-plastic model, which makes it possible to determine the bearing capacity of the system. This method eliminates the possibility of destruction of the reinforced concrete foundation from punching to the exhaustion of its bearing capacity. It further presents the results of the test conducted by the authors at Novocherkassk School for Soil Mechanics Research to validate the theoretical calculations attained with the use of the proposed method, as well as the results of tray testing of reinforced concrete foundation models. The calculation of the bearing capacity by the modernized method gives values close to the results of experimental studies. The authors discuss the challenge of determining the strength of sand base, which is known to affect the calculation of load-bearing capacity, and further propose a solution that uses piecewise linear limit line of shear strength of soil and has been developed in an attempt to increase the accuracy of calculations.
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Mirakhmedov, Mahamajon M. "The problem of sand drifts on railways." Innotrans, no. 1 (2021): 32–36. http://dx.doi.org/10.20291/2311-164x-2021-1-32-36.
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The sand drift of the railway track and the blowing of the roadbed negatively affect the elements of the track infrastructure to such an extent that they reach the limit states at which it becomes impossible for them to continue functioning. This leads to a violation of train safety. To assess the negative impact of sand and determine the necessary protective measures, a method of visual monitoring of the state of the track is proposed.
Dissertations / Theses on the topic "Sand limit state"
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RAFFAELE, LORENZO. "Windblown Sand Modelling and Mitigation for Civil Structures." Doctoral thesis, Politecnico di Torino, 2019. http://hdl.handle.net/11583/2729355.
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HORVAT, MARKO. "Computational Wind Engineering simulations for design of Sand Mitigation Measures and performance assessment." Doctoral thesis, Politecnico di Torino, 2021. http://hdl.handle.net/11583/2872324.
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Bowman, April Joy. "Performance of silty sands and their use in flexible airfield pavement design." Thesis, University of Cambridge, 2019. https://www.repository.cam.ac.uk/handle/1810/287462.
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Traditionally, flexible pavement design relies on past experience and semi-empirical methods developed through a combination of element testing and modelling. Element testing in this area especially, has centred on the performance of clean sands. This is in conflict with actual practice where a wide range of fines and soil gradations could be present in a real-world project. This research investigates the characteristics of natural sands and examines the influence of these marginal materials in pavement design using element testing and controlled modelling of an actual flexible pavement system. The element tests concentrated on separate, natural soils sourced from Kazakhstan which had similar mineralogy, but varying amounts of fines. One of the key parameters examined was equivalent void ratio and its efficiency to account for the behaviour change in granular materials which comes from increased fines content. Starting with monotonic triaxial results combined with strength-dilatancy methods it was shown that prediction of shear strength in a silty-sand could be improved by 13%. Incorporating this finding into repeat load triaxial tests, the transitions between elastic, plastic, and ratcheting failure behaviours (i.e. shakedown boundaries), commonly used to help predict the lifespan of a flexible pavement, were examined. It was seen that cycling a silty-sand, the stress path and yield surface could change depending on the fines content. The Cambridge Airfield Pavement Tester (APT) was designed and constructed to measure permanent subgrade deformation resulting from various surface loads. The number of input variables required to design flexible pavements is one of the most frequently stated problems in the field; variation of aircraft types, environmental conditions, and materials makes mechanistic design of the soil foundation problematic. Accordingly physical pavement modelling continues to be the only experimental method that allows input parameters and material characteristics to be examined simultaneously. Digital image correlation (DIC) was incorporated into the system; the first time this technology has been used in flexible pavement research. A Null Pressure System was also installed to measure soil stress distributions. It was observed that the critical failure mechanisms for thin and thick surficial layers are different, resulting in changes in the rates of surface rutting. Finally, by combining element and APT results, knowledge of the causal relationships between subsurface deformation and failure mechanisms in flexible pavement were advanced. In-situ soils, which are frequently incorporated into subgrade designs, were found to have a substantial role in the serviceability of the pavement. Correlations between element tests and APT results highlighted the complicated loading and boundary conditions present in a pavement.
Books on the topic "Sand limit state"
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Assembly, Canada Legislature Legislative. Bill: An act to enable the municipal council of the village of Elora to construct a certain road or roads beyong the limits of the said corporation. Toronto: J. Lovell, 2003.
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Assembly, Canada Legislature Legislative. Bill: An act to authorise the mayor, aldermen and citizens of the city of Montreal to borrow an additional sum for the purpose of completing the new water works in the said city, and to restrict the annual expenditure of the council of the said city within certain limits. Quebec: Thompson, Hunter, 2003.
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California. Bureau of State Audits. California Department of Corrections: A shortage of correctional officers, along with costly labor agreement provisions, raises both fiscal and safety concerns and limits management's control. Sacramento (555 Capitol Mall, Ste. 300, Sacramento 95814): California State Auditor, Bureau of State Audits, 2002.
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Imlay, Gilbert. A topographical description of the western territory of North America: Containing a succinct account of its soil, climate, natural history, population, agriculture, manners, customs ... to which are added, the discovery, settlement, and present state of Kentucky, and an essay towards the topography and natural history of that important country by John Filson, to which is added, I. The adventures of Col. Daniel Boon ... II. The minutes of the Piankashaw council ... III. An account of the Indian nations inhabiting within the limits of the thirteen United States ... London: Printed for J. Debrett ..., 1986.
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Imlay, Gilbert. A topographical description of the western territory of North America: Containing a succinct account of its soil, climate, natural history, population, agriculture, manners, customs ... to which are added, the discovery, settlement, and present state of Kentucky, and an essay towards the topography and natural history of that important country by John Filson, to which is added, I. The adventures of Col. Daniel Boone ... II. The minutes of the Piankashaw council ... III. An account of the Indian nations inhabiting within the limits of the thirteen United States ... London: Printed for J. Debrett ..., 1986.
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Legislature, Lower Canada. Bill further to continue for a limited time, and to amend two certain acts therein-mentioned, relating to the trade between this province and the United States of America, and to extend the dispositions of the said acts: Bill pour continuer encore pour un tems limité et amender deux certains actes y mentionés, relativement au commerce entre cette province et les États-Unis de l'Amérique et pour étendre les dispositions des dits actes. [Québec: s.n., 2001.
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Only at Comic-Con: Hollywood, Fans, and the Limits of Exclusivity. Rutgers University Press, 2019.
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Only at Comic-Con: Hollywood, Fans, and the Limits of Exclusivity. Rutgers University Press, 2019.
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Horne, Zachary, and Andrei Cimpian. Subtle Syntactic Cues Affect Intuitions about Knowledge. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198815259.003.0002.
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To investigate the nature and limits of knowledge, epistemologists often consult intuitions about whether people can be said to have knowledge or, alternatively, to know particular propositions. This chapter identifies a problem with this method. Although the intuitions elicited via statements about “knowledge” and “knowing” are treated as interchangeable sources of evidence, these intuitions actually differ. Building on prior psychological evidence, the chapter hypothesizes that the epistemic state denoted by the noun “knowledge” is viewed as stronger (e.g. more certain, more reliable) than the epistemic state denoted by the verb “know.” This hypothesis was supported by the results of six studies that used a variety of methodologies and data sources (e.g. philosophical texts, naive participants’ intuitions). This research has significant implications for epistemology: The syntactic structure of the linguistic examples offered as evidence for epistemological claims may influence the extent to which these examples provide intuitive support for the relevant claim.
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Sarch, Alexander. Criminally Ignorant. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780190056575.001.0001.
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Criminally Ignorant: Why the Law Pretends We Know What We Don’t is about the legal fiction that we know what we don’t. If you bury your head in the sand rather than learn you’re committing a crime, you can be punished as if you knew. How can that be justified? This book offers a framework to explain why it’s not as puzzling as it seems. When remaining ignorant of the facts is sufficiently culpable, the interests and values protected by the criminal law are served by punishing you as though you knew those facts. This idea—imputing mental states based on equal culpability—is what this book seeks to justify (at least within limits). The resulting theory shows that some legal fictions—like the willful ignorance doctrine—require reform. At the same time, it shows why we also need more legal fictions of this kind. Moreover, they should be extended to impose further accountability on corporations. Still, equal culpability imputation can be taken too far. We need to determine its limits to avoid injustice. Thus, the book seeks to place equal culpability imputation on a solid normative foundation, while demarcating its proper boundaries. The resulting theory of when and why the criminal law can pretend we know what we don’t has far-reaching implications for legal practice and reveals the pressing need for reform.
Book chapters on the topic "Sand limit state"
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Keefer, Robert F. "Engineering Aspects of Soils." In Handbook of Soils for Landscape Architects. Oxford University Press, 1999. http://dx.doi.org/10.1093/oso/9780195121025.003.0020.
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Although most landscape architects use soils primarily for growing plants, sometimes they need to know how engineers look at soils. Engineers are not concerned about soil properties that relate to growing plants. Engineers consider soil as a support for building foundations, use in earthworks, a place for burying pipes that carry electricity, water, gas or oil, and as a tool for disposing of hazardous, municipal, industrial, and household wastes. Soil properties that engineers consider important are hydraulic conductivity (permeability), compressive strength, shear strength, and lateral pressures. Soil mechanics deals with stress/strain/time relationships. Some engineering properties of a soil that describe the relation of clays to water content were studied by a Swedish scientist, Atterberg, in 1911. Soil clays based on water content were categorized into solid, semi-solid, plastic, and liquid. The dividing lines between each of these four states are known as the “Atterberg limits,” that is, shrinkage limit (from solid to semisolid), plastic limit (from semi-solid to plastic), and liquid limit (from plastic to liquid). These points can be measured for individual clays. The Atterberg limits are used by engineers to classify soils based on their moisture properties. These limits are particularly useful for evaluating soil compressibility, permeability, and strength. The plasticity of a clay soil depends on the type and amount of clay mineral and organic materials present. Plasticity is the reaction a soil has to being deformed without cracking or crumbling. The “liquid limit” is a term indicating the amount of water in a soil between the liquid state and the plastic state. Soils are first divided into two categories of coarse-grained and fine-grained. Coarse-grained soils are those in which more than half of the material is larger than a no. 200 sieve. Fine-grained soils are those in which more than half of the material is smaller than a no. 200 sieve. Coarse-grained soils are further divided into two categories of gravels and sands. Gravels are those with more than half of the coarse material larger than a no. 4 sieve. Sands are those with more than half of the coarse material smaller than a no. 4 sieve.
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Crawford, Sharika D. "Limits at Sea." In The Last Turtlemen of the Caribbean, 84–115. University of North Carolina Press, 2020. http://dx.doi.org/10.5149/northcarolina/9781469660219.003.0005.
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This chapter examines disputes over the turtle fishery across several circum-Caribbean locales: the southern cays of Cuba, the Miskito Cays of Nicaragua, and the Colombian archipelago of San Andrés, Providencia, and Santa Catalina. It shows how these conflicts over Caymanian access to turtle fishing grounds in national waters reveal the messy multilateral process of maritime boundary making, in which contestations among multiple national and imperial state actors as well as foreign and local turtlemen helped to consolidate a once porous but contested space in the circum-Caribbean. The chapter argues that legislation to regulate the turtle fishery eventually led to the closing of the turtle commons, which had been a robust transnational maritime zone.
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Tushnet, Mark, and Bojan Bugarič. "Populism and Executive Power: Term Limits and Rule by Decree." In Power to the People, 177–207. Oxford University Press, 2022. http://dx.doi.org/10.1093/oso/9780197606711.003.0010.
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When populist leaders become chief executives, it is said, they routinely seek to expand executive power so that they can speak for the people. This chapter examines two forms of expanding executive power—the elimination of presidential term limits and the use of decrees rather than statutes in emergency conditions. After laying out the political logic according to which a populist with an ambitious policy agenda might believe it impossible to implement the program within existing term limits, the chapter provides case studies of the term limit issue in Ecuador and Bolivia, and argues that, though populist leaders did indeed seek to eliminate term limits, they were not entirely successful in doing so, at least in practice. They appear to have been constrained to some extent by the people themselves, and to some perhaps small degree by their own views about the importance of implementing their reform programs, whether under their leadership or not. The chapter contrasts those cases with that of Venezuela, where Hugo Chávez probably did seek to eliminate term limits primarily to enhance his personal power. The chapter then turns to rule by decree, using responses to the Covid-19 pandemic to suggest that populist executives did not systematically exploit the crisis to expand executive power, and in the prominent cases of Brazil and the United States affirmative-disclaimed expansive power.
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Keating, Jennifer. "(Re)Claiming Shade, Roots, and Water." In On Arid Ground, 63–97. Oxford University Press, 2022. http://dx.doi.org/10.1093/oso/9780192855251.003.0003.
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Work to reclaim and restore land that had once been productive but which was believed to have fallen into dis/mis-use was a key foundation of the imperial environmental enterprise, and an inherently political act. Chapter 2 looks at state efforts to reclaim land via planting and irrigation, examining anxieties over desertification and wind-drift sands, and the political symbolism of projects such as the Murgab Imperial Estate, an experiment in irrigation at the Murgab river delta in Transcaspia. Yet comparing and contrasting the actions of imperial outsiders and Central Asian villagers and tenant farmers reveals a vast gulf between the imagined worlds of restitution and the physical realities of land degradation. Corruption, salinization, erosion, and water disputes all came to characterize schemes that had been intended to project imperial power and to act as beacons for the acceptance of Russian subjecthood. As such, the chapter points towards the gradual discovery of the instabilities and intricacies of local ecosystems and, ultimately, the limits of state land reclamation efforts. In this reading, sand, silt, and mud were powerful material agents that both enhanced and undercut imperial projections of power.
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Purcell, Kate. "The Permanent Limits of the Continental Shelf." In Geographical Change and the Law of the Sea, 75–103. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198743644.003.0005.
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This chapter traces the development of the regime of the continental shelf. It challenges the claim that UNCLOS Article 76(9) exceptionally secures the limits of the continental shelf against subsequent coastal change. The permanence of the outer limits of the continental shelf was intended to preserve an area of the seabed beyond national jurisdiction as the common heritage of mankind. The law also provides that the limits of the continental shelf beyond 200 nautical miles (M), which are not defined by distance from the coast, are ‘final and binding’. Neither Article 76(9) nor any other element of the regime of the continental shelf can be said to imply the ambulatory character of baselines and the zonal limits measured from them. Indeed, the requirement to permanently establish the limits of the continental shelf implies that the coastal State is ordinarily permitted rather than required to revise established maritime limits.
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Ziegler, Clemens. "European Union Policy on Capacity Mechanisms." In Capacity Mechanisms in the EU Energy Markets, 3—C1.F2. 2nd ed. Oxford University PressOxford, 2022. http://dx.doi.org/10.1093/oso/9780192849809.003.0001.
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Abstract The chapter sets out with a historical perspective on the EU’s policy on capacity mechanisms, discussing the early cases linked to the 2003 Electricity Directive, the Commission’s 2012/13 public consultation on resource adequacy to its 2015/16 state aid sector inquiry, and the 2019 electricity market reform. The analysis shows that, at least in theory, there is a growing tendency to limit the use of capacity payments, owing to their potentially distortive effects. That said, the discussion of the case law shows how difficult it is for third parties to challenge the Commission’s state aid assessments of capacity mechanisms, especially when these mechanisms are likely to be used for subsidizing fossil fuels. In this connection, the chapter also considers the most recent discussion regarding state aid policy and sustainability, including the Commission’s draft state aid guidelines for climate, energy, and environmental protection.
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Hardin, Garrett. "The Double C-Double P Game." In Living within Limits. Oxford University Press, 1993. http://dx.doi.org/10.1093/oso/9780195078114.003.0029.
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"Words are wise men's counters—they do but reckon by them; but they are the money of fools." So said Thomas Hobbes in the seventeenth century. Oft-repeated words, ambiguous in meaning, can easily counterfeit for the money of the mind. Free enterprise, laissez-faire, and capitalism are examples. Walter Lippmann, an esteemed commentator in the period between the two world wars, remarked on a gap between rhetoric and behavior:… Most men have shown in their behavior that they wished to impose free capitalism on others and to escape it themselves. Employers have believed in it for their employees, and have appealed to it against factory laws and unionism. But they have not hesitated to call upon the state for protection against foreign competition. . . . There is no reason to think that business men under capitalism have had any consistent conviction of laissez-faire. Their employees have certainly not had it. They have voted for tariffs when they were told their jobs depended upon them. They have voted to close the labor market by restricting immigration. They have voted for labor laws and they have organized unions. Like their employers they have believed in laissez-faire for others…. Most men believe in laissez-faire for others, while seeking to escape it themselves. A half-century after Lippmann, the economist Milton Friedman repeated the criticism: "With some notable exceptions, businessmen favor free enterprise in general but are opposed to it when it comes to themselves." This inconsistency violates the fundamental assumption of ethical theory that moral principles must be symmetrical—sauce for the goose is sauce for the gander. But it is the very nature of egoism to want sauce for the goose only: the morality Ego lives by, if he can get away with it, is asymmetrical. The discovery that social arrangements are often asymmetrical can easily lead to cynicism. One of the myths supporting free enterprise is Emerson's story of the man who built a better mouse trap and thereby became rich as the world "beat a path to his door, though he lived in the depths of the woods." In truth, however, success more often comes by another route: an ingenious man fashions a bifurcation in the accounting system that channels the costs of his enterprise to society, while directing the profits to himself.
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Konstadinides, Theodore. "The Competences of the Union." In Oxford Principles Of European Union Law: The European Union Legal Order: Volume I. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780199533770.003.0008.
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The object of this chapter is to examine the way in which competences are designed and delineated in EU law at the vertical level between the EU and the Member States and discuss their salient features. Over the years, EU competences have expanded, although not as meteorically as one may think. To alleviate concerns among Member States about the impact of EU competence enlargement upon national legal systems, a number of principles were designed to limit the powers of the EU. Having said that, there is hardly today an area of regulation in which the EU does not play an active part—from trade and energy to sport and fundamental rights protection.
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Vogel, David. "California’s Regulatory Leadership: Broader Implications." In California Greenin', 231–44. Princeton University Press, 2019. http://dx.doi.org/10.23943/princeton/9780691196176.003.0008.
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This concluding chapter reviews the key themes of the book and explores some of the broader implications of this analysis of California's regulatory leadership. Three points are particularly critical: the importance of the local dimension of environmental policies, the role of business in environmental politics, and the limits of environmental regulation. The chapter then discusses the increasingly important role states are playing in environmental protection in the United States and shows how California has economically benefited from its environmental policy leadership. One important reason why California has been able to consistently adopt more stringent regulations than those of the federal government and other states is that many of its improvements in local and state environmental quality have been a source of competitive advantage. The improvements it has made in air quality—most notably in Los Angeles—its protection of the trees in the Sierras and along the Pacific, and its land use controls along the coast and around the San Francisco Bay have all made California a more attractive place to move to, invest in, and visit.
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Hardin, Garrett. "Recapitulation and a Look Ahead." In Living within Limits. Oxford University Press, 1993. http://dx.doi.org/10.1093/oso/9780195078114.003.0033.
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The cosmopolitan approach is required for some worldwide problems, such as ozone depletion, acid rain, and the exhaustion of oceanic fisheries. By contrast, potholes and population call for a parochial orientation. But if local "laissez-faire" in population matters is interpreted to mean no borders, a suicidal commons results. To survive, rich nations must refuse immigration to people who are poor because their governments are unable or unwilling to stop population growth. With its borders secured, how is a nation to control its own population growth? In one sense population control is inevitable; in another problematical. If the citizens of a nation pay absolutely no attention to their numbers, population will eventually be controlled by "nature"—by disease, starvation, and the social disorders that follow from too many people fighting for limited resources. But when wellwishers call for "population control" they mean something gentler than nature's ultimate response. Can we now predict what form successful human measures will take? I don't think we can, because the question demands that we successfully predict human history. Who, in the year 1700, could have predicted the Constitution of the United States? Who, in 1900, could have predicted Chernobyl? What happens in history is the result of the interaction of (first) the dependable "Laws of Nature" with (second) the apparent capriciousness of human nature. As concerns the first component, Francis Bacon should be our guide: "Nature to be commanded must be obeyed." Coming to the second factor we turn to the inventor of the holograph, the Nobelist Dennis Gabor: "The future cannot be predicted, but futures can be invented." Ignorance of this insight leads the public to take too seriously the projections of demographers (who rightly insist that they cannot predict the future). Demographers merely project curves—present trends—into the unknown future, all the while knowing—as Rene Dubos said-—that trend is not destiny. This book has been one long dissertation on the laws of nature that must be obeyed, namely: the properties of exponential growth; limits generally; the properties of usury; the significance of human unreliability; and the consequences of reproductive competition (including natural selection). But within these limitations lie many possibilities of population control. Some controls are kinder than others.
Conference papers on the topic "Sand limit state"
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Hu, Jinzheng, Jie Zhang, and Lei Wang. "Value of Information Analysis for Ultimate Limit State Design of Strip Footings on Sand." In Proceedings of the 7th International Symposium on Geotechnical Safety and Risk (ISGSR 2019). Singapore: Research Publishing Services, 2019. http://dx.doi.org/10.3850/978-981-11-2725-0-is2-4-cd.
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Lopez-Puiggene, Eva, Nubia Aurora Gonzalez-Molano, Jose Alvarellos-Iglesias, Jose M. Segura, and M. R. Lakshmikantha. "Numerical Modeling of Sand Production Potential Estimation and Passive Control Optimization: A Case Study." In ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/omae2018-77851.
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Solids/sand production is an unintended byproduct of the hydrocarbon production that, from an operational point of view, might potentially lead to undesirable consequences. This paper focuses on a study centered in the geomechanical perspective for solids production. An integrated workflow is presented to analyze the combined effect of reservoir pore-pressure, drawdown, in-situ stress, rock properties and well/perforations orientation on the onset of solid production. This workflow incorporates analyses at multiple scales: rock constitutive modeling at lab scale, 1D geomechanical models at wellbore scale along well trajectories, a 3D geomechanical model at the reservoir scale and 3D/4D high resolution reservoir - geomechanical coupled models at the well and perforation scale. 1D geomechanical models were built using log and field data, drilling experience and laboratory tests in order to characterize in situ stresses, pore pressure and rock mechanics properties (stiffness and strength) profiles for several wells. Rock shear failure mechanism was also analyzed in order to build a pre-drill model and evaluate the wellbore stability from a geomechanical point of view. Pre-production stress modeling was simulated to obtain a representative initial stress state integrating 1D geomechanics well results, 3D dynamic model and seismic interpretations. Mechanical properties were distributed considering properties calculated in the 1D geomechanical models as input. 3D stress field was validated with in-situ stress profiles from 1D modeling results. This simulated pre-production stress state was then used as an initial condition for the reservoir - geomechanical coupled simulations. Effective stress changes and deformations associated to pore pressure changes were calculated including the coupling between reservoir and geomechanical modeling. Finally, a 3D/4D high resolution well scale reservoir - geomechanical coupled numerical model was built in order to determine the threshold of sand production. A limit of plastic strain was obtained based on numerical simulations of available production data, DST and ATWC tests. This critical plastic strain limit was used as a criterion (strain-based) for rock failure to define the onset of sand production as a function of pore pressure, perforation orientation and rock strength. Conclusions regarding the perforation orientations related to the possibility of producing solids can support operational decisions in order to avoid undesirable solid production and therefore optimize the production facilities capacity and design to handle large amounts of solids and/or the clogging of the well.
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Coddet, C., G. Montavon, T. Marchione, and O. Freneaux. "Surface Preparation and Thermal Spray in a Single Step: The Protal Process." In ITSC 1998, edited by Christian Coddet. ASM International, 1998. http://dx.doi.org/10.31399/asm.cp.itsc1998p1321.
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Abstract Thermal spray techniques can fulfill numerous industrial applications. Coatings are hence applied to resist against wear, corrosion, or to modify the surface characteristics of the substrate (e.g., conductivity, etc.). However, many of these applications remain inhibited by some deposit characteristics, such as a limited coating adhesion or pores, or by industrial costs since several non-synchronized steps (i.e., degreasing, sand-blasting and spraying) are needed to manufacture a deposit. The PROTAL® process was designed to reduce the aforementioned difficulties by implementing simultaneously a Q-switched laser and a thermal spray torch. The laser irradiation is aimed to eliminate the contamination films and oxide layers, to generate a surface state enhancing the deposit adhesion and to limit the contamination of the deposited layers by condensed vapors. From PROTAL® arises the possibility to reduce, indeed suppress, the preliminary steps of degreasing and sang-blasting. In addition, in some cases, a significant increase in the deposit adhesion versus standard preparation, a decrease of the porosity level and the increase of the deposit cohesion represent important additional effects of the process.
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Putra, I. Wayan Eka, Tan Chin Chien, M. Fauzi Badaruddin, M. Hilmi Isa, Cheong Xiang Hou, Liu Dongjie, and Sun Dalin. "Sand Erosion Mitigation for Offshore Pipeline and Riser – Erosion Prediction by Computational Fluid Dynamic CFD Analysis and Experimental Testing." In Offshore Technology Conference Asia. OTC, 2022. http://dx.doi.org/10.4043/31451-ms.
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Abstract Late life production of oil & gas facilities are faced with significant challenge especially when sand is produced along with the production fluid. It can cause premature failure of the equipment, for example piping and pipeline. Mitigation by adding sand removal facility is limited by space, available load, and handling at satellite wellhead platform. It also introduced additional pressure drop which limit the production that already in low pressure. One of the measures to mitigate sand erosion issue for the offshore pipeline and riser is by flow assurance, to reduce the flow velocity so that the sand velocity will be less than the erosional velocity. This mitigation comes with drawback where reducing velocity will require bigger size pipeline, higher cost, and introduce higher liquid dropout along the pipeline which will create severe slugging issue in the pipeline. Next mitigation can be done by increasing bend radius along the pipeline, to reduce impact angle of the sand to the internal surface of the pipeline. Last mitigation will be increasing resistance of the material to the sand erosion. Combination of those methodology is required to achieve the most optimum solution to mitigate sand erosion. This paper present sand erosion mitigation on one of the existing pipeline replacement projects in PETRONAS by application of unbonded flexible pipe. Modeling of the of the erosion due to sand particle solution in the pipeline was done using computational fluid dynamic finite element analysis simulation. Experimental test with samples positioned at various orientation of the riser bend location were also investigated. Concerning the exceptional balance between results efficiency and simulation time, a grid sensitivity test has also been included. Various parameters were used to verify the sensitivity of the simulation including materials properties for various fluid composition data obtained from production forecast and fluid velocity as modeled in the pipeline steady state hydraulic analysis and transient flow assurance analysis. As result, the thickness of internal carcass is found sufficient to withstand the erosion threat generated by sand particles for the entire design life of the pipeline. The results obtained from finite element analysis and erosion experimental test were then correlated, and the comparison were illustrated in graph of velocity against erosion rate for each of sand concentration. The result of the modeling and experimental testing may improve prediction model of the sand erosion in the offshore pipeline especially for flexible pipeline and riser application.
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Paik, Jeom Kee, Jung Kwan Seo, Jae Myung Lee, and Jae Hyung Park. "Ultimate Limit State Assessment of the M.V. Derbyshire Hull Structure." In 25th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/omae2006-92384.
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The Capesize bulk carrier, M.V. Derbyshire, sank in the North West Pacific during typhoon Orchid in September 1980 when she was on a voyage from Canada to Japan carrying fine iron ore concentrates. Since then, extensive investigations of the vessel sinking have previously been made in the literature primarily by the formal safety assessment (FSA) technique to explore the loss causes, but serious speculation on the failure of hull structures has been lacking in such investigations. The present paper investigates the possibility of the vessel sinking initiated by the failure of hull structures rather than by other loss scenarios such as hatch cover failure subsequent to water ingress into the cargo holds. Ultimate limit state assessments of individual stiffened panels and hulls of the M.V. Derbyshire under extreme bending moments during the last voyage in storm are made using ALPS/ULSAP and ALPS/HULL computer programs. It is concluded that the M.V. Derbyshire could have sunk by hull girder collapse with or even without unintended water ingress into cargo holds. Important insights and findings developed from the present study are summarized.
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Swminathan, V. P., Ronghua Wei, and David W. Gandy. "Erosion Resistant Nano Technology Coatings for Gas Turbine Components." In ASME Turbo Expo 2007: Power for Land, Sea, and Air. ASMEDC, 2007. http://dx.doi.org/10.1115/gt2007-27027.
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Solid particle and liquid particle erosion in the compressor section of gas turbines and steam turbine vanes and blades lead to significant reduction in turbine efficiency over time. This results in increased downtime and operating cost of the power plants. Some of the conventional coatings and erosion protection shields used by the currently available commercial processes have limitations in their temperature and erosion protection capabilities. Under a project funded by the Electric Power Research Institute (EPRI), nano coatings with thickness within 40 microns (about 1.5 mils) have been produced on test samples using a state-of-the-art Plasma Enhanced Magnetron Sputtering (PEMS) technique. Five coatings were selected for the initial screening tests. Titanium silicon carbonitride nano-composite (TiSiCN), stellite and modified stellite, chromium carbide and Ti-TiN nano layered coatings are being studies in this project. The substrate selection is based on some of the alloys currently used in aeroderivative engine compressor blades, land based gas turbine compressor blades and steam turbine blades and vanes. They include titanium alloys and stainless steels. The PEMS coating technique differs significantly from the conventional techniques such as air plasma spray (APS), low-pressure plasma spray (LPPS), diffusion coatings, chemical or physical vapor deposition (CVD or PVD) used on blades and vanes. PEMS method involves a magnetron sputtering process using a vacuum chamber with an independently generated plasma source from which high current density can be obtained. This method used heavy ion bombardment prior to and during deposition to increase the coating adhesion and limit columnar growth in the coatings. Single-layered thick nitrides coatings up to about 80μm and thick carbonitride coatings of TiSiCN about 30μm have been obtained by this process. A novel method using trimethylsilane gas instead of solid targets was successful in producing this nanocomposite. Initial tests conducted on some of the coated titanium alloy samples produced thus far show significant improvement in the erosion resistance in laboratory sand erosion tests. It was observed that TiSiCN exhibited the best low-angle erosion resistance — nearly 25 times higher than the uncoated Ti-6Al-4V and about 5–10 times higher than all other nitrides. This paper covers a brief description of the deposition technology and the properties of the coatings. Scanning Electron Microscopy (SEM) with Energy Dispersive Spectroscopy (EDS), and X-Ray diffraction (XRD) analysis were used to study the microstructure and morphology of these coatings. Nanoindentation was conducted to determine the hardness and Young’s modulus, while sand erosion tests were conducted to rank the erosion resistance of the coatings produced using several processing variables.
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Das, Prabal S., Satyabrata Nayak, Trisakti Kurniawan, and Azwari Huslan B Mohd. "Deliberate Search for Stratigraphic Traps: A Success Story from Sabah Offshore." In International Petroleum Technology Conference. IPTC, 2023. http://dx.doi.org/10.2523/iptc-22846-ea.
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Extended Abstract Abstract This article briefly discusses the workflow through which a gas discovery was made within the Late Miocene interval (Lower and Upper Stage IVD) from the structurally down-flank of a three-way fault closure, where previously an unsuccessful campaign was carried out in the structurally higher location. The causes for the failure were attributed to reservoir absence and trap incompetency. An attempt was made to understand the causes of facies variations and their limits through an integrated sequence stratigraphic approach. This model was further concretized through post-stack attributes where the limits of the seismic facies were prominent. A quantitative interpretation (QI) study coupled with forward modelling helped de-risk the reservoir presence and fluid types. Rock physics modelling work, including shear log prediction, rock property modelling, depth -trend analysis, followed by simultaneous inversion and sand probability volume generation, reveals that the deeper part of Upper Stage IVD and Lower Stage IVD intervals were shale-out and pinch-out, respectively, for the earlier campaign. Likewise, sand-dominated facies are likely at the down-dip for both intervals with an effective lateral seal up-dip (due to facies change and pinch out). Finally, this integration led to a hydrocarbon discovery in a previously written-off fault block and proved a potential stratigraphic trap presence in this area. The well encountered 50 m of net gas-bearing sand within both intervals. This approach could further facilitate exploring stratigraphic play (s) in a similar geological setup.
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Gregersen, Kathrine, Guttorm Grytøyr, Jerome De Sordi, and Kristoffer H. Aronsen. "Validation of Soil Models for Wellhead Fatigue Analysis." In ASME 2017 36th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/omae2017-61644.
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The focus on wellhead fatigue has increased over the last decade, both in terms of consequences of failure and methods for prediction. Wellhead Fatigue is a well integrity concern when drilling subsea wells, especially with exposure to harsh environments and extreme environmental loads. The concern increases with the use of deep water drilling rigs in shallow water. As a result, full-scale measurement has been employed in several projects to document the actual load levels experienced by the subsea wellheads during drilling. Input data uncertainty has always been a challenge when using global analysis to estimate wellhead fatigue. Instrumentation opens new possibilities to validate the global analysis results. In several measurement campaigns, it is observed that the response below the lower flex joint of the drilling riser is overestimated in global analyses. It has been suggested by some that this is an indication that global riser analyses are highly conservative. However, as suggested in previous papers (i.e. Russo et.al, ref.[11]), this discrepancy could also be explained by non-appropriate modelling of the conductor lateral soil resistance for small displacements, leading to underestimation of the soil stiffness. The soil spring model also called p-y curves are usually built following the API recommended methods that are established for foundation piles. Piles are designed for ultimate limit state focusing on displacement conditions that are not optimal for fatigue analyses, as a large part of the total fatigue damage actually occurs for small displacements. A literature review is conducted, to review the basis for the API springs, and alternative p-y-curves with increased initial stiffness have been suggested. Based on the available information four alternative soil models have been proposed. The work performed by BP on p-y curves modelling for laterally loaded conductors (ref. [2]) has been an important input for this paper. In order to illustrate the effect of initial soil stiffness in the global analysis, the present study focuses on conductors installed in homogenous and normally consolidated to slightly overconsolidated clays. This limits somewhat the number of available sites with relevant conditions for full-scale measurements, at least on the Norwegian Continental Shelf, where it is common to find layers of sand interspersed between the clay layers. However, Statoil have conducted one campaign with full-scale measurements at a location with corresponding clay conditions. In this paper, the API formula for “soft clay” and four alternative soil models, have been used as input to a global riser analysis, and the results are validated against measurements. It is the response of the lower stack, in terms of rotations and displacements of BOP, LMRP and LRS, that has been investigated. In addition, the load, in terms of wellhead bending moment has been compared. Results shows that for this given case, the Matlock-API formulation overestimates the lower stack response, compared with full-scale measurements. Comparing the proposed soil models shows that the global response is affected by selection of soil model. The soil formulations outlined by Jeanjean (2009) and Zakeri et.al (2015) give the best match with full-scale measurements for this case.
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Veliyev, Fuad H., Elkhan M. Abbasov, and Sayavur I. Bakhtiyarov. "Energy Saving Technology Based of Negative Pressure Phenomenon." In ASME/JSME 2007 5th Joint Fluids Engineering Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/fedsm2007-37098.
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Negative pressure is one of the metastable states of liquids at which it can be extended up to a certain limit without a gap of continuity. There are numerous experimental studies where a negative pressure up to 40 MPa has been obtained at laboratory conditions. However, these results of the experimental works were not practically implemented, as real liquids both in the nature and the technological processes contain impurities. Under certain kinetic and hydrodynamic conditions the waves of negative pressure in real liquids (crude oil, water, and water-based solutions) were observed. The wave of negative pressure is a turned soliton wave with one negative hump. It is a conservative wave, which maintains its shape and dimensions, and travels long distances with the speed of sound. An advanced technology of generation of the negative pressure wave in real systems allowed creating completely new energy saving technology. This technology based on negative pressure phenomenon has been already used for increasing oil production efficiency during various oil well operations, cleaning of oil well bore, and pipelines from various accumulations. It is shown that a new technology has a lot of potentials for bottom-hole cleaning operations, oil recovery enhancement, pipeline transportation, gas-lift operation etc. Negative pressure is known to be one of the metastable states at which liquids can be extended up to a certain limit. Theoretic evaluations show that in pure liquids negative pressure may reach large values while the liquid may stand significant extending efforts. For instance, the maximum negative pressure that may be sustained by ideally pure water is estimated as −109N/m2. It means that an imaginable rope of completely pure water with the diameter of 0.01m can sustain a huge extending effort more than 105 N. It is evident that the real experimental values of negative pressure are much less than the corresponding theoretic estimations. It is connected with the impossibility of obtaining ideally pure liquids without any “weak places” (gas bubbles, admixture, etc) and with the circumstance that in experience, the rupture often happens not in the liquid volume but on the surface touching the walls of the vessels weakened by the existence of thin films, embryos, etc. There are numerous results of the experimental work of static and dynamic character, where negative pressure has appeared in one or another degree [1]. In laboratory conditions, negative pressure apparently was first revealed in the experiences made by F. M. Donny (1843), who used degassed sulfuric acid and obtained negative pressure only −0.012 MPa. Among the further attempts of receiving bigger negative pressure, it is worth mentioning the experiences made by O.Reynolds, M.Bertelot and J.Meyer. Basing upon a centrifugal method and using mercury, L.J.Briggs obtained the record value of negative pressure (−42.5 MPa). But as a matter of fact, beginning from the first experiences by F. M. Donny, the main condition in the investigations for the appearance of negative pressure has been the homogeneous character of the liquid and high degree of the purity the liquid-vessel system. Significant values of negative pressure has been obtained under those conditions, however these results of a great scientific importance have no effective applications in practice as real liquids in Nature and technological processes are heterogeneous multicomponent systems. A long-term experimental work has been done to generate negative negative pressure in real liquid systems and investigate influence of this state on thermohydrodynamical characteristics of natural and technological processes [2,3]. Basing on the idea that negative pressure can be created due to the sudden character of extending efforts a direct wave of the negative pressure in real liquids (water, oil, solutions etc.) have been obtained experimentally. For impulsive entering into metastable (overheated) zone in a phase diagram “liquid-vapor” the pressure should drop so fast that the existing centers of evaporation (bubbles, embryos, admixtures etc.) would not be able to manifest themselves for this period. In these terms purity of the liquid is not decisive, and herewith there might exist states of an overheated liquid with the manifestation of negative pressure. It was determined that wave of the negative pressure resembling overturned soliton wave with one but negative peak propagates with speed of sound. The typical variation of the pressure in the petroleum stream in pipe is given in Figure 1. Reversed wave of the negative pressure was not recorded during the experiments. Evidently this is associated with considerable structural changes in the liquid after the passing of the direct wave. The arising negative pressure though being a short-term, results in a considerable overheating of the fluid system and leads to spontaneous evaporation and gas-emanation with the further cavitation regime. It was determined that after passing of the negative pressure wave hydraulic resistance in the system becomes much less, and significant increase of permeability of the porous medium and intensification of the filtration process take place. On the base of the investigations it was made a conclusion that any discharge in the hydraulic systems when the drop of the pressure requires much less time that relaxation of the pressure in the system inevitably results in the arising of rarefaction wave, in particular, the negative pressure wave [4]. The larger is the hydraulic system and the higher is the depression of the pressure, the more intensively the negative pressure wave may manifest itself. In certain terms waves of the positive pressure may be reflected from free surfaces, different obstacles, from contact surfaces between phases in the form of the reverse wave of the negative pressure. On this base there were presented numerous theoretical and experimental works on the simulation of the process, investigation of impact of the negative pressure on certain physical features of real systems [5]. The negative pressure wave may lead to very hard complications: showings of oil and gas leading sometimes to dreadful open fountains, borehole wall collapse, column crushing, gryphon appearance [6]. Analysis of numerous facts of complications, troubles in wells as water-oil-gas showings, crushing of columns, collapses, gryphon formation demonstrates that they arise usually as a result of round-trip operations in drilling of wells and their capital repairs. The negative pressure wave may be initiated by a sudden pulling of pipes or drilling equipment, as well as their sudden braking, quick opening of a valve at the well exit, etc, resulting in metastable extension of the working fluid agent. Though impulse negative pressure manifests itself as a significant dynamic factor, its structural consequences are more dangerous for an oil well. Moving along a well the negative pressure wave results in the spontaneous boiling of the water in the drilling fluid, and as a result of considerable reduction of its specific weight the hydrostatic column is “switched-off’ for some seconds and this may be sufficient for oil and gas showings of the well to be appeared accompanied often by crushing of columns and collapsing of wells due to great destroying energy manifestation. Negative pressure waves may be considered also as one of the dominant factors in geophysical processes, especially, in evolution and appearance of volcanic eruptions and earthquakes [7,8]. Extreme dynamic processes in the underground medium as a matter of fact can be considered as a synergetic manifestation of the negative pressure together with other thermohydrodynamical factors. The waves of negative pressure in the underground environment may be initiated by tectonic dislocations and faults as a result of different dynamic processes, dramatic decrease of pressure during the displacement of fluids and rocks. They may arise also in the form of a reverse waves as a result of reflection of ordinary seismic waves from different underground surfaces. On the basis of received results the method of artificial creation of negative pressure waves has been created [4]. The essence of the method is that negative pressure waves can be generated by means of discharge in hydraulic systems (pipes, wells, etc) when the drop of the pressure takes place during the characteristic time much less than that of pressure relaxation in the system. The greater is the volume of hydraulic system and the higher is the depression of the pressure, the more intensively the negative pressure wave may manifest itself. This method was taken as a basis of elaboration of principally new technologies and installations to increase effectiveness and efficiency of some oil recovery processes. It has been worked out and widely tested in field conditions new technologies on using of the negative pressure phenomenon for cleaning of oil producing hydraulic systems/well bore, pipeline/from various accumulations and increasing of effectiveness of oil producing at different well operation methods. The technology provides generation negative pressure waves in the well using the special mechanisms that leads to the shock depression impact upon the oil stratum, and as a result, to considerable growth in the oil influx, bottom-hole cleaning, accompanied by essential saving both reservoir and lifting energies, elimination and prevention of sandy bridging, paraffin, silt, water, etc. accumulations. For implementations of these technologies corresponding installations have been elaborated, in part, equipments for cleaning out of oil holes from sand plugs, increasing of efficiency and effectiveness of gas-lift well operations and bottom-hole pumping. In cleaning out of oil-holes from sand plugs the most operative and effective liquidation of different sand plugs irrespective of their rheological character is provided, associated with complete bottom-hole cleaning, essential increase of oil recovery and overhaul period. Elaborated equipment is simple and easy to use. Other comparatively advantageous application of the technology provides increase of efficiency of a gas-lift well operation, expressed in considerable reduction of a specific gas consumption associated with essential increase of oil recovery and overhaul period. The design of the equipment is reliable and simple to service. There are different modifications of the equipment for single-row, double-row lifts in packer and packerless designs. The introduced technologies have passed broad test in field conditions. The operative and complete cleaning of numerous oil wells was carried out, where the altitude of sand plugs varied from 20m to 180m; oil output of wells and their overhaul period have been increased and specific gas discharge reduced significantly.
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Myo Thant, Maung Maung, M. Faizal Che Daud, Siti Nur Amira Shaffee, and M. Faizal Sedaralit. "Sustainability Driven Produced Water Treatment Technology Solution at Nano-Scale." In ADIPEC. SPE, 2022. http://dx.doi.org/10.2118/211170-ms.
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Abstract Treatment and disposal costs of produced water from oil and gas operations remain the primary concern with the ongoing global push toward the transition to cleaner energy and Zero Liquid Discharge (ZLD). Gas floatation utilizing micro-size bubbles is commonly used in produced water treatment. However micro-size bubbles are not effective in removing dissolved oil (such as Benzene, Toluene, Ethyl-benzene, and Xylene) and usually require chemical pre-treatment to remove the emulsified oil. This paper aims to present the challenges, and lessons learned from produced water treatment technologies as well as recent technology development in nano-bubble floatation technology with a concept select study of pilot deployment at one of the terminals in Malaysia. First, state-of-the-art analysis of existing gas floatation technology to treat produced water is presented. From the analysis, the failures and lesson-learned from the technology implementations are identified. To improve the efficiency of gas floatation technology, the effects of reducing the micro-sized bubble to a nano-sized bubble, bubble concentration, and type of gas have been evaluated. Subsequently, several improvements are developed and tested to overcome existing gas floatation technology. The pilot application of this developed technology at one of the crude oil terminals in Malaysia, which include a feasibility study, concept selection and engineering of this technology is described as a case study. The typical gas floatation system is much less efficient in produced water where dissolved oil fraction is high and, in the presence of the fines solid. As a result, the required oil in water separation is not met leading to disposal limit compliance issues and the poor recovery of hydrocarbon in produced water. Changing operating envelope over time i.e., reduced production, increased water cut, and fines sand production, affects gas floatation efficiency over time. It is also not cost-effective to produce large volumes of microbubbles that are smaller than oil droplets. From our analysis, a significant improvement in oil-in-water (OIW) removal is achieved by controlling the bubble size, gas type, and bubble concentrations via a nano-bubble floatation unit. This technology successfully maintains the less than 10ppm OIW target removal and a further reduction in the required treatment stages and chemical consumption. The system is a promising technology for brown and green facilities, wet or dry terminals, or even for downhole applications to increase oil recovery. New design elements are proposed to increase separation efficiency under erratic multiphase-flow conditions, increased water cuts, and the presence of fine particles. Testing results of the compact, low-energy, high reliable nanoscale gas floatation system are presented and are a promising technology for both aging and new facilities.
Reports on the topic "Sand limit state"
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Méndez-Vizcaíno, Juan C., and Nicolás Moreno-Arias. A Global Shock with Idiosyncratic Pains: State-Dependent Debt Limits for LATAM during the COVID-19 pandemic. Banco de la República, October 2021. http://dx.doi.org/10.32468/be.1175.
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Fiscal sustainability in five of the largest Latin American economies is examined before and after the COVID-19 pandemic. For this purpose, the DSGE model in Bi(2012) and Hürtgen (2020) is used to estimate the Fiscal Limits and Fiscal Spaces for Peru, Chile, Mexico, Colombia, and Brazil. These estimates advance the empirical literature for Latin America on fiscal sustainability by offering new calculations stemming from a structural framework with alluring novel features: government default on the intensive margin; dynamic Laffer curves; utility-based stochastic discount factor; and a Markov-Switching process for public transfers with an explosive regime. The most notable additions to the existing literature for Latin America are the estimations of entire distributions of public debt limits for various default probabilities and that said limits critically hinge on both current and future states. Results obtained indicate notorious contractions of Fiscal Spaces among all countries during the pandemic, but the sizes of these were very heterogeneous. Countries that in 2019 had positive spaces and got closer to negative spaces in 2020, have since seen deterioration of their sovereign debt ratings or outlooks. Colombia was the only country to lose its positive Fiscal Space and investment grade, thereby joining Brazil, the previously sole member of both groups
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Busby, Ryan, H. Torbert, and Stephen Prior. Soil and vegetation responses to amendment with pulverized classified paper waste. Engineer Research and Development Center (U.S.), May 2022. http://dx.doi.org/10.21079/11681/44202.
Full textAbstract:
The United States Army produces a significant amount of classified paper waste that is pulverized to a fine consistency unsuitable for recycling. However, cheap, high quality organic materials such as classified paper waste are useful as soil amendments. The objective of this research was to evaluate the utilization of pulverized classified paper waste as a soil amendment to improve soil health and increase establishment of desirable native grasses on degraded Army training lands. Paper was applied at rates of 9 to 72 Mg ha⁻¹ to two soil types at Fort Polk, LA: an alfisol (very fine sandy loam - Fine, smectitic, thermic Chromic Vertic Hapludalfs) and an ultisol (loamy fine sandy - Loamy, siliceous, semiactive, thermic Arenic Paleudults). These are common soil orders found on military training lands nationwide and represent fertile (alfisol) and unfertile (ulitsol) soils. Vegetation and soils were monitored over 2 growing seasons. No increase in heavy metals were observed in soils. Extensive analysis showed very low levels of regulated contaminants in the paper, but most were below detection limits. The ultisol site showed improved soil physical and chemical properties, while desirable vegetation benefitted from nutrient immobilization at the alfisol site. Based on the results of this study, applying pulverized paper waste to soil at a rate of 35.9 Mg ha⁻¹ is recommended. Application of paper waste to soils had no adverse environmental effects, improved soil physiochemical properties, and facilitated establishment of desirable native vegetation.
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Ayala, David, Ashley Graves, Colton Lauer, Henrik Strand, Chad Taylor, Kyle Weldon, and Ryan Wood. Flooding Events Post Hurricane Harvey: Potential Liability for Dam and Reservoir Operators and Recommendations Moving Forward. Edited by Gabriel Eckstein. Texas A&M University School of Law Program in Natural Resources Systems, September 2018. http://dx.doi.org/10.37419/eenrs.floodingpostharvey.
Full textAbstract:
When Hurricane Harvey hit the Texas coast as a category 4 hurricane on August 25, 2017, it resulted in $125 billion in damage, rivaling only Hurricane Katrina in the amount of damage caused. It also resulted in the deaths of 88 people and destroyed or damaged 135,000 homes. Much of that devastation was the result of flooding. The storm dumped over 27 trillion gallons of rain over Texas in a matter of days. Some parts of Houston received over 50 inches of rainfall. The potential liability that dam and reservoir operators may face for decisions they make during storm and flooding events has now become a major concern for Texas citizens and its elected officials. Law suits have now been instituted against the federal government for its operation of two flood control reservoirs, as well as against the San Jacinto River Authority for its operation of a water supply reservoir. Moreover, the issues and concerns have been placed on the agenda of a number of committees preparing for the 2019 Texas legislative session. This report reviews current dam and reservoir operations in Texas and examines the potential liability that such operators may face for actions and decisions taken in response to storm and flooding events. In Section III, the report reviews dam gate operations and differentiates between water supply reservoirs and flood control reservoirs. It also considers pre-release options and explains why such actions are disfavored and not recommended. In Section IV, the report evaluates liabilities and defenses applicable to dam and reservoir operators. It explains how governmental immunity can limit the exposure of state and federally-run facilities to claims seeking monetary damages. It also discusses how such entities could be subject to claims of inverse condemnation, which generally are not subject to governmental immunity, under Texas law as well as under the Fifth Amendment to the U.S. Constitution. In addition, the Section discusses negligence and nuisance claims and concludes that plaintiffs asserting either or both of these claims will have difficulty presenting successful arguments for flooding-related damage and harm against operators who act reasonably in the face of storm-related precipitation. Finally, Section V offers recommendations that dam and reservoir operators might pursue in order to engage and educate the public and thereby reduce the potential for disputes and litigation. Specifically, the report highlights the need for expanded community outreach efforts to engage with municipalities, private land owners, and the business community in flood-prone neighborhoods both below and above a dam. It also recommends implementation of proactive flood notification procedures as a way of reaching and alerting as many people as possible of potential and imminent flooding events. Finally, the report proposes implementation of a dispute prevention and minimization mechanism and offers recommendations for the design and execution of such a program.