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Auswahl der wissenschaftlichen Literatur zum Thema „Counter-Intuitive Issues“
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Zeitschriftenartikel zum Thema "Counter-Intuitive Issues"
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Shams Alizadeh, Mehdi, Kourosh Heidari Shirazi, Shapour Moradi und Hamid Mohammad Sedighi. „Numerical analysis of the counter-intuitive dynamic behavior of the elastic-plastic pin-ended beams under impulsive loading with regard to linear hardening effects“. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 232, Nr. 24 (15.01.2018): 4588–600. http://dx.doi.org/10.1177/0954406217753456.
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The counter-intuitive behavior where the permanent deflection of elastic-plastic beam come to rest in the opposite direction of the impulsive loading, normally appears and disappears abruptly, in certain small ranges of loading and structural parameters. One of the most important issues in the study of this phenomenon is the determination of the influence of different parameters. This work is aimed to study the effects of hardening in counter-intuitive dynamic behavior of elastic-plastic pin-ended beams under impulsive loading. This has been done by developing the proposed Galerkin numerical model and presenting a novel algorithm. The Galerkin method as well as the commercial finite element code ANSYS/LS-DYNA is applied to study this phenomenon. In order to account for the hardening effects in Galerkin method, a new algorithm is proposed. The time history curves for mid-span of the beam is studied in detail and the region of the occurrence of the counter-intuitive behavior is determined. Furthermore, using the finite element software, energy diagrams of the beam are also derived. It has been found that the counter-intuitive behavior is a phenomenon, which is very sensitive to loading, therefore it may appear with a little change in the amount of loading. The results also show that although both methods predict one continuous region of loading for the occurrence of this phenomenon in elastic-perfectly plastic beams, still there are two continuous distinct regions of loading, when considering the hardening effects, for this phenomenon. In addition, this anomalous behavior would occur in the proper ratios of kinetic to internal energy and when considering the linear hardening effects, the possibility of the occurrence of the counter-intuitive behavior exists in a wider domain of energy ratio.
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Znamenskaya, I. I., M. R. Travkova und K. R. Arutyunova. „Psychotherapy of a Relationship Break-Up in the Context of Assisted Reproductive Technologies“. Консультативная психология и психотерапия 29, Nr. 1 (2021): 132–48. http://dx.doi.org/10.17759/cpp.2021290108.
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The paper is focused on ethical issues of making decisions about cryopreserved embryos in the context of relationship break-up in the framework of the embryo’s legal status and the church’s stand on the matter. All these issues can be viewed as part of a broader problem of intuitive and rational foundations for decision-making when facing difficult situations in life. On the one hand, the stressful context of the situation implies intuitive-driven decision-making; on the other hand, assisted reproductive technologies are largely counter-intuitive. We describe the peculiarities of family psychotherapy with mixed-agenda couples going through a divorce who have joint cryopreserved embryos but disagree on what to do with them. We introduce a protocol for psychotherapeutic work in the situation when one partner wishes to continue with the fertility treatment and have a child while the other partner is determined to utilize joint embryos as unwanted biological material. In addition, we discuss emotional and social complications that may arise (guilt, unfaithfulness of one of the partners, other losses, and grieving).
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Thomann, Robert V., und Lewis C. Linker. „Contemporary issues in watershed and water quality modeling for eutrophication control“. Water Science and Technology 37, Nr. 3 (01.02.1998): 93–102. http://dx.doi.org/10.2166/wst.1998.0183.
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Three issues are discussed: controllability of nonpoint nutrient loadings using watershed models; the sometimes counter intuitive results from eutrophication models from nutrient controls for coastal waters; and the potential significant interaction of improvement in habitat for suspension feeding bivalves. For the Chesapeake Bay watershed model, and for Limit of Technology (LOT) controls, a 16% and 45% reduction in nitrogen and phosphorus, respectively, is calculated. For the Bay, it is concluded that removal of phosphorus only is less effective than nitrogen in improving bottom water DO because of differential transport of nitrogen downstream. For the Delaware estuary, a significant decline in phytoplankton chlorophyll has been observed in the absence of any nutrient controls but in the presence of improved DO. A simple model is offered that hypothesized an increase in benthic bivalve filtration of overlying water as a result of improvement in DO.
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Attfield, Robin. „Biocentric Consequentialism, Pluralism, and ‘The Minimax Implication’: A Reply to Alan Carter“. Utilitas 15, Nr. 1 (März 2003): 76–91. http://dx.doi.org/10.1017/s0953820800003782.
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Alan Carter's recent review in Mind of my Ethics of the Global Environment combines praise of biocentric consequentialism (as presented there and in Value, Obligation and Meta-Ethics) with criticisms that it could advocate both minimal satisfaction of human needs and the extinction of ‘inessential species’ for the sake of generating extra people; Carter also maintains that as a monistic theory it is predictably inadequate to cover the full range of ethical issues, since only a pluralistic theory has this capacity. In this reply, I explain how the counter-intuitive implications of biocentric consequentialism suggested by Carter (for population, needs-satisfaction, and biodiversity preservation) are not implications, and argue that since pluralistic theories (in Carter's sense) either generate contradictions or collapse into monistic theories, the superiority of pluralistic theories is far from predictable. Thus Carter's criticisms fail to undermine biocentric consequentialism as a normative theory applicable to the generality of ethical issues.
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Clarke, Harold D., William Mishler und Paul Whiteley. „Recapturing the Falklands: Models of Conservative Popularity, 1979–83“. British Journal of Political Science 20, Nr. 1 (Januar 1990): 63–81. http://dx.doi.org/10.1017/s0007123400005706.
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Recently, Sanders et al. have made the intriguing and counter-intuitive argument that the impact of the Falklands war on Conservative popularity was inconsequential. Their analyses raise important theoretical and methodological issues concerning the time-series analysis of party support. This present article contends that the stepwise regression procedures employed by Sanders et al. are misleading, particularly when predictor variables are highly intercorrelated. Box-Jenkins analyses demonstrate that the Falklands strongly influenced Conservative support, net of the effects of macroeconomic conditions and personal economic expectations. The significance of the latter variable in the models confirms Sanders et al.'s argument about the role of subjective economic variables in party popularity functions. Non-economic variables are also relevant, however, and popularity functions that model them correctly will enhance our understanding of both the economics and the politics of party support.
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Bekiros, Stelios, Nikolaos Loukeris, Iordanis Eleftheriadis und Gazi Uddin. „Revisiting the three factor model in light of circular behavioural simultaneities“. Review of Behavioral Finance 10, Nr. 3 (13.08.2018): 210–30. http://dx.doi.org/10.1108/rbf-08-2017-0079.
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Purpose The authors construct asset portfolios comprising small-sized companies and value stocks that provide with higher returns for the UK market based on a three-factor model with incorporated behavioural features. The authors were able to demonstrate that value factor model is vulnerable to behavioural patterns, especially corporate fraud. In all of the above, the authors utilised a new proportional sorting methodology against the value ranking approach, commonly employed in empirical studies. Strong evidence is observed that portfolio performance based on various syntheses of allocated assets reveals counter-intuitive results related to the BE/ME, namely, that expected returns based on size and BE/ME produce significant errors and small firms retain consistently better returns. The reason might be the unusual accounting techniques many firms follow to receive extended capital after management decisions. The paper aims to discuss these issues. Design/methodology/approach The authors were able to demonstrate that value factor model is vulnerable to behavioural patterns, especially corporate fraud. In all of the above, authors utilised a new proportional sorting methodology against the value ranking approach, commonly employed in empirical studies. Strong evidence is observed that portfolio performance based on various syntheses of allocated assets reveals counter-intuitive results related to the BE/ME, namely, that expected returns based on size and BE/ME produce significant errors and small firms retain consistently better returns. The reason might be the unusual accounting techniques many firms follow to receive extended capital after management decisions. Findings Value factor model is vulnerable to behavioural patterns, especially corporate fraud. In all of the above, the authors utilised a new proportional sorting methodology against the value ranking approach, commonly employed in empirical studies. Strong evidence is observed that portfolio performance based on various syntheses of allocated assets reveals counter-intuitive results related to the BE/ME, namely, that expected returns based on size and BE/ME produce significant errors and small firms retain consistently better returns. The reason might be the unusual accounting techniques many firms follow to receive extended capital after management decisions. Overall, asset pricing models with embedded risk factors which entail either shares or dividends are logically circular behavioural simultaneities, thus invalid when tested and estimated by statistical methods as an outcome of the EMH. Originality/value In distinctive contrast to the recent literature, the authors show that the returns from a size factor model of small stocks tend to outperform big stocks especially in crisis periods. Moreover, the authors were able to demonstrate that value factor model is vulnerable to behavioural patterns, especially corporate fraud. In all of the above, the authors utilised a new proportional sorting methodology against the value ranking approach, commonly employed in empirical studies. Strong evidence is observed that portfolio performance based on various syntheses of allocated assets reveals counter-intuitive results related to the BE/ME, namely, that expected returns based on size and BE/ME produce significant errors and small firms retain consistently better returns. The reason might be the unusual accounting techniques many firms follow to receive extended capital after management decisions. Overall, asset pricing models with embedded risk factors which entail either shares or dividends are logically circular behavioural simultaneities, thus invalid when tested and estimated by statistical methods as an outcome of the EMH.
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Baines, Paul. „Death and best interests“. Clinical Ethics 3, Nr. 4 (Dezember 2008): 171–75. http://dx.doi.org/10.1258/ce.2008.008040.
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I will consider how we can assess the interests of critically ill children who will survive only while aggressive medical support is continued. If aggressive medical support is withdrawn, the child will die shortly afterwards. This is important because when the courts are asked to decide treatments, the standard is that decisions should be made in the best interests of the child. My claim is that this is not a coherent way to consider how some children in this situation should be treated. I will consider two separate aspects of this problem. First, I will argue that there is no objective best interests test and no immediate prospect that we will be able to develop one. Secondly, I will argue that best interests are not a coherent way to consider the interests of children who will die shortly after treatment is withdrawn. To reinforce this claim, I will describe an example of two children where acting in the child's best interests produces counter-intuitive conclusions.
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Baruch, Yehuda, Rea Prouska, Ariane Ollier-Malaterre und Jennifer Bunk. „Swearing at work: the mixed outcomes of profanity“. Journal of Managerial Psychology 32, Nr. 2 (13.03.2017): 149–62. http://dx.doi.org/10.1108/jmp-04-2016-0102.
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Purpose The purpose of this paper is to explore the use and misuse of swearing in the workplace. Design/methodology/approach Using a qualitative methodology, the authors interviewed 52 lawyers, medical doctors and business executives in the UK, France and the USA. Findings In contrast to much of the incivility and social norms literatures, the authors find that male and female business executives, lawyers and doctors of all ages admit to swearing. Further, swearing can lead to positive outcomes at the individual, interpersonal and group levels, including stress-relief, communication-enrichment and socialization-enhancement. Research limitations/implications An implication for future scholarship is that “thinking out of the box” when exploring emotion-related issues can lead to new insights. Practical implications Practical implications include reconsidering and tolerating incivility under certain conditions. Originality/value The authors identified a case in which a negative phenomenon reveals counter-intuitive yet insightful results.
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Jaisal, E. K. „The US, China and Huawei Debate on 5G Telecom Technology: Global Apprehensions and the Indian Scenario“. Open Political Science 3, Nr. 1 (22.04.2020): 66–72. http://dx.doi.org/10.1515/openps-2020-0006.
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AbstractAdvancements in connectivity and telecommunications have redefined the ways people access information and services. The 5th Generation of telecom technology which is set to open up new avenues and opportunities have but stirred up a series of escalating tensions between two mighty powers in global politics- the US and China. While 5G offers an array of options for global trade and co-operation to flourish, it has generated counter-intuitive results, at least temporarily, with the US adopting a protectionist standpoint to contain the Chinese dominance in the telecom sector, citing security concerns. The US lobbying against Chinese vendors, particularly Huawei, has generated uncertainty among countries on the adoption and deployment of equipment provided by the firm. The paper attempts to comprehend the issues revolving around Huawei, its extent of influence, the global impact of US sanctions and to explore the ways forward for countries like India.
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Rydning Gaarder, Anders, und Krishna C. Vadlamannati. „Does democracy guarantee (de)forestation? An empirical analysis“. International Area Studies Review 20, Nr. 2 (27.01.2017): 97–121. http://dx.doi.org/10.1177/2233865916688846.
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It is a commonly held view that democracy is better at safeguarding environment while autocracy is predatory in nature, and is thus insensitive towards environment. However, others argue that democracy leads to environmental degradation. We revisit this contentious relationship between regime type and environment degradation in the context of deforestation. Using panel data on 139 countries during the 1990–2012 period, we find that democracy is associated with lower levels of forest coverage. Although our results appear counter-intuitive, further analyses reveal the positive effect of democracy on forest area coverage is conditional upon the level of economic development. Roughly, at per capita income of about US$8200, the impact of democracy on forest coverage becomes positive. Our results suggest that a democratic government’s priority to tackle environmental problems depends on its level of economic development. These results also highlight the fundamental reason as to why there is a lack of coordinated effort between developing and developed countries in addressing environmental issues.
Dissertationen zum Thema "Counter-Intuitive Issues"
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Das, Debarchana. „On Some Conceptual and Counter-Intuitive Issues in Relativity Theory“. Thesis, University of North Bengal, 2013. http://hdl.handle.net/123456789/1509.
Der volle Inhalt der QuelleBücher zum Thema "Counter-Intuitive Issues"
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Chiari, Sophie. Shakespeare's Representation of Weather, Climate and Environment. Edinburgh University Press, 2019. http://dx.doi.org/10.3366/edinburgh/9781474442527.001.0001.
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While ecocritical approaches to literary texts receive more and more attention, climate-related issues remain fairly neglected, particularly in the field of Shakespeare studies. This monograph explores the importance of weather and changing skies in early modern England while acknowledging the fact that traditional representations and religious beliefs still fashioned people’s relations to meteorological phenomena. At the same time, a growing number of literati stood against determinism and defended free will, thereby insisting on man’s ability to act upon celestial forces. Yet, in doing so, they began to give precedence to a counter-intuitive approach to Nature. Sophie Chiari argues that Shakespeare reconciles the scholarly views of his time with more popular ideas rooted in superstition and that he promotes a sensitive, pragmatic understanding of climatic events. She pays particular attention to A Midsummer Night’s Dream, Romeo and Juliet, As You Like It, Othello, King Lear, Anthony and Cleopatra, and The Tempest. Taking into account the influence of classical thought, each of the book’s seven chapters emphasises specific issues (e.g. cataclysmic disorders, the dog days’ influence, freezing temperatures, threatening storms) and considers the way climatic events were presented on stage and how they came to shape the production and reception of Shakespeare’s drama.
Buchteile zum Thema "Counter-Intuitive Issues"
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Stone, David. „The System of Courts and Tribunals with Jurisdiction for European Union Design Disputes“. In European Union Design Law. Oxford University Press, 2016. http://dx.doi.org/10.1093/oso/9780198719298.003.0003.
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Kottler, Jeffrey A., und Richard S. Balkin. „Mythology and Ethics“. In Myths, Misconceptions, and Invalid Assumptions About Counseling and Psychotherapy, 202–14. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780190090692.003.0014.
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In Mythology and Ethics the authors note the difficulty in navigating emotional and values-based conflicts. Cases of counter-transference are common and require an awareness by the therapist to address the conflict. Sometimes a referral could be necessary. But when such conflicts are values-based, ethical bracketing is recommended, which runs counter-intuitive to countertransference. Individual change, even for therapists, can be difficult, and although the research basis for counter-transference is well-established, extant research on ethical bracketing is very limited. Such issues, along with other ethical mandates such as confidentiality, can compromise client trust. Moreover, although therapists may strive to be honest with clients, transparency and honesty are not always easy to maintain. Therapists cannot guarantee the success of a client or know that an intervention will be effective. Yet, such statements often persist in counseling.
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Weiskrantz, Lawrence. „Blindsight—Putting Beta (β) on the Back Burner“. In Out of Mind, 20–33. Oxford University PressOxford, 2001. http://dx.doi.org/10.1093/oso/9780198506300.003.0002.
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Abstract Blindsight is the capacity for making visual discriminations in the absence of acknowledged awareness, associated with damage to the visual cortex. Subjects can reach for briefly presented stimuli, can discriminate orientation, movement direction, wavelength, and so forth. In fact, the field has expanded recently. B. de Gelder and her colleagues have demonstrated discrimination of emotional expression of faces (1999; 2000). Robert Kentridge and colleagues (1999) have shown that an unseen cue in the blind field can direct attention to an unseen target. However, this subject is not reviewed here. Other relatively recent reviews are available (Weiskrantz, 1997, 1998; Cowey and Stoerig, 1991; Stoerig and Cowey, 1997), to which these latest references can be added. Instead this chapter concentrates on some of the logical issues involved in its demonstration and interpretation. Blindsight is an example of implicit processing. All examples of implicit processing in neuropsychology are, to varying degrees, counter-intuitive, and hence subject to sceptical attack, but perhaps blindsight is the most counter-intuitive of them all, and historically it has been questioned on fronts that are unique to it. The typical case of damage to V1 is unilateral, and hence there is an intact half-field of normal vision. Therefore doubts have been raised as to whether the ‘intact’ performance seen in the blind field genuinely originates from stimuli within it, but instead might be based on artefactual stimulation of the intact visual field—either because of stray light in the display environment or spread of light within the ocular media (Campion et al., 1983). This was a legitimate concern, but various stringent controls, e.g. use of the optic disc as a control, leave no doubt that blindsight can be processing of stimuli genuinely restricted to the blind field (review by Weiskrantz, 1998).
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Chessa, Massimo, Werner Budts und Javier Fernandez Sarabia. „Cardiovascular screening of children and adolescent athletes (<14 years)“. In The ESC Textbook of Sports Cardiology, herausgegeben von Antonio Pelliccia, Hein Heidbuchel, Domenico Corrado, Mats Börjesson und Sanjay Sharma, 359–66. Oxford University Press, 2019. http://dx.doi.org/10.1093/med/9780198779742.003.0040.
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Sport is not in itself the cause of enhanced mortality. During physical activity physiological changes, such as increased catecholamine levels, acidosis, and dehydration, can trigger cardiac arrest in those young athletes who are affected by underlying cardiovascular disorders. Because sports can prompt adverse events from underlying cardiac disease, pre-participation screening has been advised as strategy in the prevention of sudden cardiac death (SCD) in competitive athletes. SCD is rare in young healthy athletes, but remains a tragic and counter-intuitive event, subject to persistently high public visibility, triggering of emotion, and media attention, with potential legal liability considerations. Pre-participation screening in children and adolescent athletes can be done by an experienced specialist (paediatrician, family doctor, cardiologist, or sports medicine specialist); it includes family and personal history, physical examination (including blood pressure), and resting 12-lead ECG. All these issues are discussed in this chapter.
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Liu, Zhe. „New Tanimoto Similarity Measures Between Pythagorean Fuzzy Sets with Applications on Pattern Recognition“. In Advances in Transdisciplinary Engineering. IOS Press, 2023. http://dx.doi.org/10.3233/atde231035.
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Pythagorean fuzzy sets (PFSs) are a versatile tool for handling uncertain problems and have proven effective in practical applications. However, many existing Pythagorean fuzzy similarity measures have counter-intuitive situations, making it challenging to measure the similarity or difference between PFSs accurately. To address this issue, we propose two similarity measures for PFSs inspired by the Tanimoto similarity measure. We also explore the properties of the proposed measures and provide several numerical examples to illustrate their superior performance in processing fuzzy information from PFSs. Finally, we demonstrate the applicability of the proposed measures in solving pattern recognition problem.
Konferenzberichte zum Thema "Counter-Intuitive Issues"
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Fifield, Leonard S., Robert Duckworth und Samuel W. Glass. „Long Term Operation Issues for Electrical Cable Systems in Nuclear Power Plants“. In 2016 24th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/icone24-60729.
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Nuclear power plants contain hundreds of kilometers of electrical cables including cables used for power, for instrumentation, and for control. It is essential that safety-related cable systems continue to perform following a design-basis event. Wholesale replacement of electrical cables in existing plants facing licensing period renewal may be both impractical and cost-prohibitive. It is therefore important to understand the long term aging of cable materials to have confidence that aged cables will perform when needed. It is equally important in support of cable aging management to develop methods to evaluate the health of installed cables and inform selective cable replacement decisions. The most common insulation materials for electrical cables in nuclear power plants are cross-linked polyethylene and ethylene-propylene rubber. The mechanical properties of these materials degrade over time in the presence of environmental stresses including heat, gamma irradiation, and moisture. Mechanical degradation of cable insulation beyond a certain threshold is unacceptable because it can lead to insulation cracking, exposure of energized conductors, arcing and burning or loss of the ability of the cable system to function during a design-basis accident. While thermal-, radiation-, and moisture-related degradation of polymer insulation materials has been extensively studied over the last few decades, questions remain regarding the long term performance of cable materials in nuclear plant-specific environments. Identified knowledge gaps include an understanding of the temperature-dependence of activation energies for thermal damage and an understanding of the synergistic effects of radiation and thermal stress on polymer degradation. Many of the outstanding questions in the aging behavior of cable materials relate to the necessity of predicting long-term field degradation using accelerated aging results from the laboratory. Materials degrade faster under more extreme conditions, but extension of behavior to long term degradation under more mild conditions, such as those experienced by most installed cables in nuclear power plants, is complicated by the fact that different degradation mechanisms may be involved in extreme and mild scenarios. The discrepancy in predicted results from short term, more extreme exposure and actual results from longer term, more mild exposures can be counter intuitive. For instance, due to the attenuation of oxidation penetration in material samples rapidly aged through exposure to high temperatures, the bulk of the samples may be artificially protected from thermal aging. In another example, simultaneous exposure of cable insulation material to heat and radiation may actually lead to less damage at higher temperatures than may be observed at lower temperatures. The Light Water Reactor Sustainability program of the United States (US) Department of Energy (DOE) Office of Nuclear Energy is funding research to increase the predictive understanding of electrical cable material aging and degradation in existing nuclear power plants in support of continued safe operation of plants beyond their initial license periods. This research includes the evaluation and development of methods to assess installed cable condition.
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LaFleur, Ronald S. „A Scale Independent Model for Turbine Surface Cooling“. In ASME Turbo Expo 2008: Power for Land, Sea, and Air. ASMEDC, 2008. http://dx.doi.org/10.1115/gt2008-50428.
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As part of an undergraduate course in design of thermodynamic systems, a highly loaded turbine, such as a power turbine or high bypass turbofan, is modeled as a modified Brayton cycle. On a smaller scale, the vane, blade, liner and seal surfaces of modern high pressure turbine (HPT) parts are exposed to gas path temperatures that far exceed the base metal material-life capability. A cooling method such as compressor bleed allows high combustion temperatures to attain high turbine output but is considered a negative on overall cycle performance. The required cooling flow must be included as its impact on the cycle-scale calculations can be significant. At the thermodynamic education level, the cooling model for part surfaces must be such that expertise in heat transfer is not required. At the same time, the cooling model for the cycle must represent key influences of cooling technologies. To bridge this educational gap, a scale independent model for surface cooling is required. This is important because thermodynamic cycle conditions impact detailed surface cooling features and, in the opposite direction, surface-material cooling demands are calculated in the cycle model. The cooling issues are scale independent when characteristic temperatures track the engine and surface cooling design. A surface cooling model is shown with five cooling technologies working in tandem: film cooling, thermal barrier coating (TBC), base metal conduction, passage convection cooling and backside convection cooling. Six new definitions for cooling technology effectivenesses are introduced. The result is a basis for communicating the impact of small scale cooling design on large scale engine performance. Two applications at different scales, the cooling demand for a rotor stage and the film decay over a 1st vane surface patch, are used to demonstrate the model and show where counter-intuitive results may arise.
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Xiao, Y., H. Vaziri, D. Saraswaty, I. Muhamad, I. Yusifov, V. Fataliyev, W. Abdellatif und I. Sheta. „Sanding in Response to Dynamic Changes in Downhole Conditions“. In SPE Annual Technical Conference and Exhibition. SPE, 2023. http://dx.doi.org/10.2118/215089-ms.
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Abstract Downhole conditions from the sanding risk viewpoint refer to anything in the downhole that affects rock disaggregation and sandface fluid flux, two principal factors dictating well’s sanding response. Often times similar wellhead flow rate and pressure may be associated with drastically different downhole conditions and their dynamic changes, resulting in complex and counter-intuitive sanding responses. Due to their practical significance but difficulties in reliably predicting all of them in advance, this paper describes a sanding-physics-based data integration approach to get them consistently identified for the practical purpose of taking the right course of action to safely maximize well’s flow potential, and prevent, mitigate and manage well-specific sanding issues. It requires a multi-disciplinary effort and cross-referencing well production histories fieldwide is an integral part. Equally important are the prior sanding-mechanisms-based empirical relations between sanding severity and driving factors, refined reservoir engineering simulation, and numerical sanding prediction that considers effects of rock disaggregation, depletion, drawdown, fluid flux and water in one-go. Three field cases are presented to illustrate the approach. Each case is distinctively different although they all involve cased & perforated (C&P) high-rate gas wells in competent formations that have been online for years but without formation water breakthrough yet. In Case-1 uniform reservoir pressure distributions between reservoir formation subunits and production logging tool (PLT) surveys in each well have provided a reliable delineation of gas flux distributions and shut-in induced temporary wellbore water buildups. That has led to a consistent understanding of well specific sanding in relation to high gas flux and water buildups at a low rock disaggregation state. In Case-2 differential reservoir pressures /depletions in different units of a multi-stacked reservoir pay system under a commingled production have resulted in dynamic changes in drawdown, gas flux and downhole water activities, and thus complex sanding responses including prolonged perforation debris cleanout, high drawdown induced sanding and water-crossflow induced sanding during post shut-in production ramping. In Case-3 a thorough review of limited data available in 4 wells has inferred that the interaction between smectite-bearing formation intervals and temporary wellbore water buildups and its limited near-wellbore damage and subsequent self-cleanup under drawdown and gas flux are responsible for observed well-specific cyclic changes in drawdown and minor sand events prior to depletion induced rock disaggregation. Despite observed sand production in all 3 fields neither permanent production chokeback nor intervention are needed to date. Rather, well specific sand management strategies and surveillance tailored toward tendencies of well-specific dynamic changes in downhole conditions have been implemented to safely achieve the targeted gas rate.
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Hessami, Mir Akbar, und Justine White. „Improved Fluid Circulation and Heat Transfer in Geothermal Reservoirs due to Superior Fracture Network in Hot Dry Rocks (HDR)“. In ASME 2012 6th International Conference on Energy Sustainability collocated with the ASME 2012 10th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/es2012-91271.
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As the reduction of carbon emissions becomes an increasingly pressing issue, a larger emphasis is being placed on the need for the development of renewable energy. One such option is geothermal energy which utilizes the heat from the earth’s crust; it presents a vast potential for the production of commercial scale base-load power generation. However, the conventional techniques used in the stimulation of hot dry rocks (HDR) geothermal wells are not very effective in producing a permeable reservoir for heat exchange between the rock mass and the working fluid. To increase the permeability of geothermal reservoirs, a new stimulation technique (developed by CSIRO - Commonwealth Scientific and Industrial Research Organisation) which involves isolating sections of the well for controlled planar fracture growth can be used. However, if these notches/fractures are placed too closely together they will interact with one another, resulting in a deviated fracture path. A two dimensional numerical model has thus been developed to study conditions under which adjacent fractures will interact with one another. This study aims to verify the numerical model through stimulating a number of granite blocks, and drawing comparisons between the observed fracture pattern and that predicted by the model. To achieve this goal, the stimulated and fractured granite blocks were sectioned and their fracture patterns were extracted using a MATLAB code, before being reconstructed in their respective positions. Stimulation was carried out firstly using conventional techniques, and then by trialling the method proposed by CSIRO. Observation of the reconstructed images showed good agreement between the model predictions and the observed fracturing patterns in two-dimensions. However, the three-dimensional pattern in the notched, perpendicular well-bore was observed as a ‘half cylinder’. This was counter intuitive as it was expected that radial symmetry of the fractures would be observed resulting in a ‘bowl’ shape. It was therefore concluded that while the model was unable to accurately predict the three-dimensional geometry of an array of fractures, stimulation through a notched perpendicular wellbore was very effective in the production of a controlled system of fractures with an improved fluid flow and heat exchanging surface area of the reservoir in comparison to the conventional techniques.
Berichte der Organisationen zum Thema "Counter-Intuitive Issues"
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Private Sector Performance Contracting in the Water Sector: The Case of SABESP: Case Study. Inter-American Development Bank, November 2004. http://dx.doi.org/10.18235/0011161.
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Water systems in Latin America are inefficient in part because of very low relative investment and in part because of the lack of availability of necessary management tools. One way to address both of these issues at the same time is the performance financing of micro-metering by private sector companies. This case study is written to highlight the counter-intuitive fact that the great inefficiencies in Latin American water systems offer strong opportunities for public/private risk sharing. Specifically addressed is the case of the water company Sabesp in São Paulo and their affect on the market.