Academic literature on the topic 'Stress presentation mode'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Stress presentation mode.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Stress presentation mode"
1
Terpou, Braeden A., Maria Densmore, Jean Théberge, Janine Thome, Paul Frewen, Margaret C. McKinnon, and Ruth A. Lanius. "The Threatful Self: Midbrain Functional Connectivity to Cortical Midline and Parietal Regions During Subliminal Trauma-Related Processing in PTSD." Chronic Stress 3 (January 2019): 247054701987136. http://dx.doi.org/10.1177/2470547019871369.
Full textAbstract:
Background The innate alarm system consists of a subcortical network of interconnected midbrain, lower brainstem, and thalamic nuclei, which together mediate the detection of evolutionarily-relevant stimuli. The periaqueductal gray is a midbrain structure innervated by the innate alarm system that coordinates the expression of defensive states following threat detection. In participants with post-traumatic stress disorder, the periaqueductal gray displays overactivation during the subliminal presentation of trauma-related stimuli as well as altered resting-state functional connectivity. Aberrant functional connectivity is also reported in post-traumatic stress disorder for the default-mode network, a large-scale brain network recruited during self-referential processing and autobiographical memory. Here, research lacks investigation on the extent to which functional interactions are displayed between the midbrain and the large-scale cortical networks in post-traumatic stress disorder. Methods Using a subliminal threat presentation paradigm, we investigated psycho-physiological interactions during functional neuroimaging in participants with post-traumatic stress disorder (n = 26) and healthy control subjects (n = 20). Functional connectivity of the periaqueductal gray was investigated across the whole-brain of each participant during subliminal exposure to trauma-related and neutral word stimuli. Results As compared to controls during subliminal threat presentation, the post-traumatic stress disorder group showed significantly greater periaqueductal gray functional connectivity with regions of the default-mode network (i.e., angular gyrus, precuneus, superior frontal gyrus). Moreover, multiple regression analyses revealed that the functional connectivity between the periaqueductal gray and the regions of the default-mode network correlated positively to symptoms of avoidance and state dissociation in post-traumatic stress disorder. Conclusion Given that the periaqueductal gray engages the expression of defensive states, stronger midbrain functional coupling with the default-mode network may have clinical implications to self-referential and trauma-related processing in participants with post-traumatic stress disorder.
2
Schütte, Henning, and Kianoush Molla-Abbasi. "On the Influence of the Corner Singularity on Kinking Mixed-Mode Crack Propagation." Key Engineering Materials 348-349 (September 2007): 585–88. http://dx.doi.org/10.4028/www.scientific.net/kem.348-349.585.
Full textAbstract:
The aim of the presentation is to highlight the influence of the kink, developing at the beginning of mixed-mode crack growth, on the propagation behavior of the crack. Le et al. [1] have shown that the variational principle of a body containing a crack results in the principle of maximum energy release rate incorporating the stress intensity factors of the kinked crack. Here the influence of the kink and the kinking angle, resulting in a singular field around the corner, on the crack growth is analyzed. The generalized stress intensity factors at the kinks corner are computed with the help of a FEM strategy. The influence of these on the T-stresses and the plastic energy dissipated at the kink is determined using a small scale yielding approach. The impact of these results on mixed-mode crack propagation is discussed.
3
Liu, Yong-Qiang, Hong-Quan Song, and Jiang Shen. "Interfacial potential approach for Ag/Si(111) interface." Modern Physics Letters B 30, no. 09 (April 10, 2016): 1650104. http://dx.doi.org/10.1142/s0217984916501049.
Full textAbstract:
By applying the Chen–Möbius inversion method, a concise formula is introduced to get the pair potentials of the Ag/Si(111) interface by inversion of the ab initio adhesive energies. The check shows that the inversed potentials are self-consistent. Then, by using the interfacial potentials obtained, we analyze the changes of the energy, stress and atomic structures, giving a detailed presentation of the fracture process about the Ag/Si(111) interface. Meanwhile, we know that there are three kinds of fracture mode. In this work, the fracture process is performed in mode II (shear).
4
Larisa, Stepanova. "Intermediate self-similar asymptotic presentation of stress and damage fields in the vicinity of mixed mode crack tip under creep regime." Procedia Structural Integrity 13 (2018): 255–60. http://dx.doi.org/10.1016/j.prostr.2018.12.043.
Full text
5
Liang, Dongxu, Nong Zhang, and Haoyu Rong. "Study on the Effect of Continuity and Load Angle of Prefabricated Cross-Flaws on Crack Initiation and Coalescence." Shock and Vibration 2021 (August 4, 2021): 1–17. http://dx.doi.org/10.1155/2021/8705178.
Full textAbstract:
In this study, a model that is closer to the state of fracture presentation in natural rocks has been developed, which is different from the previous. The cross-flaws can be characterized by the joint persistency ( k ) and the angle between the primary flaws and axial load ( α ). The two parameters were varied individually and, by combining them, nine specimens with different nodal parameters were formed. Laboratory specimens and numerical simulations were performed on these specimens to investigate the crack extension process and the variation of crack initiation and coalescence stresses. It is found that a new category of crack coalescence is discovered according to the experimental results besides those reported before, and the angle α affects whether tensile-shear cracks appear. Also, α has an impact on the location where crack first occurs. The joint persistency k alters rock failure mode and has a substantial effect on crack initiation stress. However, the effect on the aggregation stress is not significant. The crack initiation stress decreases in the case of cross-flaws in contrast to flat fissures. In addition, the flat-joint model in PFC2D is used for numerical simulation. It is possible to conduct a study that is difficult to achieve experimentally by using simulations, i.e., only changing one macroparameter without changing others and thus studying the changes in the effect on cracking during fracture. The simulation results are in good agreement with the experimental results. At the same time, the connection mode and the width of the crack coalescence zone of the primary defect, which is difficult to observe in the experiment, are found out from the numerical simulation.
6
Pipinos, Iraklis I., Stanley A. Swanson, Zhen Zhu, Aikaterini A. Nella, Dustin J. Weiss, Tanuja L. Gutti, Rodney D. McComb, B. Timothy Baxter, Thomas G. Lynch, and George P. Casale. "Chronically ischemic mouse skeletal muscle exhibits myopathy in association with mitochondrial dysfunction and oxidative damage." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 295, no. 1 (July 2008): R290—R296. http://dx.doi.org/10.1152/ajpregu.90374.2008.
Full textAbstract:
A myopathy characterized by mitochondrial pathology and oxidative stress is present in patients with peripheral arterial disease (PAD). Patients with PAD differ in disease severity, mode of presentation, and presence of comorbid conditions. In this study, we used a mouse model of hindlimb ischemia to isolate and directly investigate the effects of chronic inflow arterial occlusion on skeletal muscle microanatomy, mitochondrial function and expression, and oxidative stress. Hindlimb ischemia was induced by staged ligation/division of the common femoral and iliac arteries in C57BL/6 mice, and muscles were harvested 12 wk later. Muscle microanatomy was examined by bright-field microscopy, and mitochondrial content was determined as citrate synthase activity in muscle homogenates and ATP synthase expression by fluorescence microscopy. Electron transport chain (ETC) complexes I through IV were analyzed individually by respirometry. Oxidative stress was assessed as total protein carbonyls and 4-hydroxy-2-nonenal (HNE) adducts and altered expression and activity of manganese superoxide dismutase (MnSOD). Ischemic muscle exhibited histological features of myopathy and increased mitochondrial content compared with control muscle. Complex-dependent respiration was significantly reduced for ETC complexes I, III, and IV in ischemic muscle. Protein carbonyls, HNE adducts, and MnSOD expression were significantly increased in ischemic muscle. MnSOD activity was not significantly changed, suggesting MnSOD inactivation. Using a mouse model, we have demonstrated for the first time that inflow arterial occlusion alone, i.e., in the absence of other comorbid conditions, causes myopathy with mitochondrial dysfunction and increased oxidative stress, recapitulating the muscle pathology of PAD patients.
7
Gallo, Pasquale, and Alberto Sapora. "Brittle Failure of Nanoscale Notched Silicon Cantilevers: A Finite Fracture Mechanics Approach." Applied Sciences 10, no. 5 (February 29, 2020): 1640. http://dx.doi.org/10.3390/app10051640.
Full textAbstract:
The present paper focuses on the Finite Fracture Mechanics (FFM) approach and verifies its applicability at the nanoscale. After the presentation of the analytical frame, the approach is verified against experimental data already published in the literature related to in situ fracture tests of blunt V-notched nano-cantilevers made of single crystal silicon, and loaded under mode I. The results show that the apparent generalized stress intensity factors at failure (i.e., the apparent generalized fracture toughness) predicted by the FFM are in good agreement with those obtained experimentally, with a discrepancy varying between 0 and 5%. All the crack advancements are larger than the fracture process zone and therefore the breakdown of continuum-based linear elastic fracture mechanics is not yet reached. The method reveals to be an efficient and effective tool in assessing the brittle failure of notched components at the nanoscale.
8
R., Vasuki, Arun P. S., and Rajesh Menon Moothedath. "A rare case of spontaneous gastric perforation in an adolescent." International Surgery Journal 5, no. 9 (August 25, 2018): 3171. http://dx.doi.org/10.18203/2349-2902.isj20183743.
Full textAbstract:
Incidence of Peptic ulcer perforation in children and adolescents are very rare. Perforated gastric ulcer is extremely rare with only handful of cases reported worldwide in the same age group. Pneumoperitoneum and peritonitis due to gastric perforation is a very rare presentation in children and adolescents and it can often be overlooked with disastrous consequences. Even though in young patients, peptic ulcerations can happen in association with H. pylori infection, secondary to medications like non-steroidal anti-inflammatory agents, corticosteroids, rarely due to Zollinger Ellison syndrome, related to stress, post burns or head trauma it is seldom common. Among perforations gastric perforation is very rare. Here we discuss a case of 15-year-old school student who presented with acute abdominal pain and features of peritonitis which we initially thought probably due to perforated appendix but turned out to be a gastric perforation. Plain radiograph of the abdomen showed pneumoperitoneum. When an emergency midline laparotomy was performed, we found a perforation in gastric antrum anteriorly with peritonitis which was treated by thorough decontamination and Graham's live omental patch closure. H. Pylori tests were negative. At a time when acute presentation of peptic ulcerations or perforation as its complication is decreasing in incidence worldwide, this case has come as an eye opener. Thus, perforated gastric/duodenal ulcer in pediatric and young adult patient should not be overlooked in a young patient presenting with acute abdomen. Many times, there is no clear etiology and then it is spontaneous perforation. Emergency surgical management is the preferred mode of treatment.
9
Griffin, Dee. "76 Shipping calves to the Southern Great Plains: Impact of mode, timing, distance and cattle type." Journal of Animal Science 97, Supplement_1 (July 2019): 24–25. http://dx.doi.org/10.1093/jas/skz053.054.
Full textAbstract:
Abstract This presentation will discuss historical transportation information, recommendations and available transportation data. Stocker and feeder cattle transportation in the U.S. is virtually unchanged in the last five decades. Transportation stress continues to be accepted as an important factor in the morbidity and mortality of cattle shipped to Southern Great Plains feedyards and stocker operations. Transportation research has occurred in bits and pieces that provide glimpses into mechanisms involved but in general the results are puzzle pieces that have had little influence on transportation techniques. The Electronic Logging Device (ELD) use mandate in livestock hauling will impact stocker and feeder transport to the Great Plains. The extent of which is not yet known and recent delays in implementation with concurrent “exceptions” and “adjustments” make it unclear what the future will hold for stocker and feeder cattle transportation. The Livestock Marketing Association (LMA) has in recent decades developed voluntary livestock handling and transportation training for their customers. Some of the training has been accomplished in a partnership with the National Cattlemen’s Beef Association (NCBA). The first of these were the “Focal Point” training and “Master Transporter Guide.” More recent, NCBA has developed Beef Quality Assurance (BQA) Transportation certification training for both “Farmer/Rancher” and “Professional Drivers.” Packers have embraced this effort and the major packers currently require all drivers delivering livestock to their operations to be certified. The NCBA BQA Transportation training certification is applicable to stocker and feeder drivers hauling cattle to the Great Plains, but currently it is rare that stocker and feeder operations require drivers to have transportation certification that bring cattle to their operations. Interesting and useful data will be reviewed, such as transportation data collected from Dr. Richeson and Dr. Lawrence at West Texas A&M University. Finding examples include; cattle during transportation can take thousands of steps while on in the semi-trailer with differing number of steps and G-Forces being recorded for cattle on the top deck compared to cattle on the lower deck.
10
Triantafyllidis, N., M. D. Nestorović, and M. W. Schraad. "Failure Surfaces for Finitely Strained Two-Phase Periodic Solids Under General In-Plane Loading." Journal of Applied Mechanics 73, no. 3 (September 1, 2005): 505–15. http://dx.doi.org/10.1115/1.2126695.
Full textAbstract:
For ductile solids with periodic microstructures (e.g., honeycombs, fiber-reinforced composites, cellular solids) which are loaded primarily in compression, their ultimate failure is related to the onset of a buckling mode. Consequently, for periodic solids of infinite extent, one can define as the onset of failure the first occurrence of a bifurcation in the fundamental solution, for which all cells deform identically. By following all possible loading paths in strain or stress space, one can construct onset-of-failure surfaces for finitely strained, rate-independent solids with arbitrary microstructures. The calculations required are based on a Bloch wave analysis on the deformed unit cell. The presentation of the general theory is followed by the description of a numerical algorithm which reduces the size of stability matrices by an order of magnitude, thus improving the computational efficiency for the case of continuum unit cells. The theory is subsequently applied to porous and particle-reinforced hyperelastic solids with circular inclusions of variable stiffness. The corresponding failure surfaces in strain-space, the wavelength of the instabilities, and their dependence on micro-geometry and macroscopic loading conditions are presented and discussed.
Dissertations / Theses on the topic "Stress presentation mode"
1
Brattos, Alexandra. "The Effect of Stress Presentation Mode on Stress Acquisition Among Advanced Learners of Russian." BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3140.
Full textAbstract:
The purpose of this research was to test the effect of stress presentation mode on stress acquisition of advanced learners of Russian. The study attempted to determine if advanced learners of Russian are able to place stress more correctly on words in specific texts after receiving various treatments or receiving no treatment. Participants were Brigham Young University students studying Russian as a second language at the third-year level or higher. They were randomly assigned into three groups: a group that received no treatment, a treatment group that read words with graphically marked stress, and a treatment group that heard texts read by a native speaker. All participants completed a pretest, a treatment (in the second and third groups), and a posttest. The pretest and the posttest consisted of a reading task: the participants read 12 sentences taken from 12 different texts. The same words from the texts were used in the treatment to expose the participants to the sentences again in order to determine if the treatment made a difference in the acquisition of correct stress. The treatment was different for each group. Group 1 (A) read texts marked with stress, Group 2 (B) read the same texts but without stress marked; rather, they heard a native speaker of Russian read the texts on a recording, and Group 3 (C) read the same texts but without stress marked graphically or hearing a native speaker. The results of the research reject the hypothesis that aural presentation of stress as opposed to a visual only presentation leads to improved acquisition of stress. However, based on the analyses of the data, overall findings rendered some interesting and unexpected results and observations. First, although the treatment for group A appears to be more effective than that for groups B and C, all groups showed improvement after completing the treatment. This strongly suggests that reading, whatever form it takes, can be a useful tool in facilitating control of stress. Second, group A had more participants that fell into the "fast" reading category, and fast readers scored significantly higher than slow or medium speed readers. This suggests that the faster one reads the better one controls stress, or the better one controls stress the faster one reads.
2
Coleman, Joshua B., Wesley Drew Gill, Allee C. Maxwell, and Russell W. Brown. "Analysis of a Poly(ADP-ribose) Polymerase (PARP) Inhibitor in a Treatment-resistant Depression Model in the Rat." Digital Commons @ East Tennessee State University, 2020. https://dc.etsu.edu/asrf/2020/presentations/53.
Full textAbstract:
Over 16 million people in the US suffer from major depressive disorder (MDD) each year. Approximately 1/3rd of MDD patients (~5 million) obtain only partial remission or no benefit after trials with multiple drugs or drug combinations. Recently, Ordway and colleagues have reportedelevated levels of DNA oxidation and upregulated gene expression of the base excision repair enzyme poly(ADP-ribose) polymerase-1 (PARP1) in postmortem brain from donors who had MDD at the time of death, as compared to age-matched psychiatrically normal control donors. This study was designed to test whether an inhibitor of PARP, 3-aminobenzamide (3-AB), may be effective to alleviate depressive-like behaviors in a rodent model of treatment-resistant depression. Male rats were ip administered lipopolysaccharide (LPS;100ug/kg) daily for 28 days, and administered a chronic unpredictable stressor on each day. All rats were also administered saline, 3-AB (40 mg/kg), or the serotonin-reuptake inhibitor (SSRI) fluoxetine (trade name: Prozac; 10 mg/kg) on each day, approximately 30 min after LPS treatment. During the 28 day period of LPS treatment, animals were behaviorally tested 5 times on sucrose preference (a test of anhedonia). At the end of the 28 day period, rats were behaviorally tested on a test of acute stress, the Porsolt swim test. Results revealed that 3-AB alleviated anhedonia and the response to acute stress in the Porsolt swim test superior to the fluoxetine group, demonstrating the utility of a PARP inhibitor to alleviate depressive-like behavior in this model. In addition, fluoxetine produced a loss of weight which recovered over days, but not to control levels, and 3-AB did not produce this effect. This study shows that PARP inhibitors may be effective in treatment-resistant depression.
Books on the topic "Stress presentation mode"
1
Shitov, Viktor. The art of hospitality. ru: INFRA-M Academic Publishing LLC., 2021. http://dx.doi.org/10.12737/1016654.
Full textAbstract:
The textbook describes the basics of the art and culture of hospitality, hospitality as part of modern business, modern models of hospitality, hospitality as a component of everyday life, hospitality in everyday life, the technology of meeting and greeting guests, the rules of greeting in the premises, on the street, the norms and rules of professional behavior and business etiquette, the basics of departmental etiquette, relations in professional activities, communication by phone, methods of holding various events, presentations and receptions, culinary art of different peoples and much more.
Nine practical works are described in detail, as well as independent work in the study of the discipline of MDK. 01.01 "The art of hospitality".
For students of secondary vocational education institutions. It can be used when mastering the module PM. 01 "Management of household management" for the specialty 43.02.08 "Service of household and communal services".
2
Seedat, Soraya, and Sharain Suliman. PTSD in Low- and Middle-Income Countries. Edited by Charles B. Nemeroff and Charles R. Marmar. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780190259440.003.0009.
Full textAbstract:
The burden of post-traumatic stress disorder (PTSD) in low- and middle-income countries (LMIC) is high. In addition to trauma type and sociodemographic correlates, cultural and social drivers of the disorder are critical to consider in diagnosis and treatment provision. Sociocultural factors may underpin the cognitive and affective neural mechanisms of PTSD and its phenotypic presentation. Although steps have been taken to evaluate and disseminate empirically supported interventions for PTSD in LMIC that are feasible, affordable, and potentially sustainable despite the limited resources that exist in these countries, well-designed quantitative and qualitative randomized controlled trials are needed in order to gain a more nuanced understanding of the cultural expressions of PTSD.
3
Shrout, Patrick, Katherine Keyes, and Katherine Ornstein. Causality and Psychopathology. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199754649.001.0001.
Full textAbstract:
Part of the new American Pyschopathological Association Series. Containing contributions from leading scholars of causal thinking in epidemiology and psychopathology research, this volume is based on presentations at the ground-breaking 2008 meeting of the American Psychopathological Association. The authors explore the meaning of causal statements that are made from statistical and experimental evidence; then, they suggest novel approaches to analyze these statements and thus make them more informative and medically rigorous. The collection of chapters uniquely includes both methodological contributions and detailed assessments of how causal inferences can be made when considering research results on developmental psychopathology, clinical psychopharmacology, personality disorders, post-traumatic stress disorder, and psychiatric genetics. In analyzing causal references, the authors examine controversies surrounding various disorders and their treatment.
4
Gropman, Andrea L., Belen Pappa, and Nicholas Ah Mew. The Urea Cycle Disorders. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780199937837.003.0063.
Full textAbstract:
The urea cycle is the primary nitrogen disposal pathway in humans. The urea cycle requires the coordinated function of six enzymes and two mitochondrial transporters to catalyze the conversion of a molecule of ammonia, the α-nitrogen of aspartate and bicarbonate into urea. Whereas ammonia is toxic, urea is relatively inert, soluble in water, and readily excreted by the kidney in the urine. The accumulation of ammonia and other toxic intermediates of the cycle lead to predominantly neurological sequelae. All of the genes have been identified. The disorders may present at any age from the neonatal period to adulthood, with the more severe patients presenting earlier in life. Patients are at risk for metabolic decompensation throughout life, often triggered by illness, fasting, surgery and postoperative states, peripartum, stress, and increased exogenous protein load. This chapter addresses common somatic and neurological presentation, differential diagnosis, laboratory testing, and treatments.
5
Katirji, Bashar. Case 7. Edited by Bashar Katirji. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780190603434.003.0011.
Full textAbstract:
Diabetic amyotrophy is a relatively uncommon neurological complication of diabetes mellitus. However, the disorder is often not recognized by internists and neurologists and misdiagnosed as myopathy, radiculopathy, or peripheral polyneuropathy. The discussion starts by outlining the classification of the diabetic neuropathies. This case highlights the classical clinical presentation of diabetic amyotrophy, also referred to as diabetic polyradiculoplexopathy or subacute diabetic neuropathy, in a man with pain in the anterior thigh and knee followed by thigh and hip weakness. It also emphasizes the electrodiagnostic findings including the subacute needle electromyography changes and stresses the frequent coexistence of diabetic amyotrophy with the more common distal peripheral polyneuropathy in the majority of patients.
6
Peris, Tara S., and John Piacentini. Helping Families Manage Childhood OCD. Oxford University Press, 2016. http://dx.doi.org/10.1093/med:psych/9780199357604.001.0001.
Full textAbstract:
Childhood obsessive compulsive disorder (OCD) is a complex condition that is often accompanied by high levels of family stress and strain. Families of youth with OCD face a unique set of difficulties in that they often are intimately involved in their children’s symptoms. This pattern of responding to OCD, frequently referred to as accommodation, comes in many forms, and for most families, it occurs daily. Research suggests that accommodation is accompanied by increased levels of family distress, anxiety, and conflict, which, when high enough, can undermine successful OCD treatment. Although evidence-based treatments exist for childhood OCD, few protocols offer strategies for treating these more complex family presentations. This program offers an empirically supported approach for managing childhood OCD complicated by poor family functioning. It identifies specific family features that may contribute to treatment nonresponse in childhood OCD, and provides clinicians with an innovative set of strategies for addressing them. By focusing on emotion-regulation strategies and family-problem-solving exercises, families learn to troubleshoot difficult OCD episodes in an effective and supportive manner.
7
Morgan, Robert. Christ. Edited by Joel D. S. Rasmussen, Judith Wolfe, and Johannes Zachhuber. Oxford University Press, 2017. http://dx.doi.org/10.1093/oxfordhb/9780198718406.013.19.
Full textAbstract:
Most nineteenth-century Christians continued to take the divinity of Christ for granted, but, following the Enlightenment challenge to biblical and ecclesiastical authority and the rise of historical consciousness, the focus of theologians shifted to his humanity. Schleiermacher shared the rationalist rejection of supernaturalism and was critical of Chalcedon’s ‘two natures’ conceptuality but defended the divinity of Christ in terms of his perfect humanity. His presentation depended on the substantial historicity of the Fourth Gospel which was undermined by subsequent historical criticism. Strauss separated belief in divine immanence from the historical figure. Others built their historical sense into incarnational theologies, but following Renan (1863) lives of Jesus could scarcely acknowledge his divinity. The erosion of scriptural authority was widely contested and orthodox reactions reaffirmed the dogma. That pointed ahead to more recent attempts to integrate tradition and modernity rather than choosing between them.
8
AlJaroudi, Wael. Risk Assessment in Acute Coronary Syndromes. Oxford University Press, 2015. http://dx.doi.org/10.1093/med/9780199392094.003.0013.
Full textAbstract:
Acute coronary syndromes (ACS) include unstable angina pectoris (UAP), non-ST elevation (NSTEMI), and ST elevation acute myocardial infarction (STEMI). Each year, more than 2 million people are hospitalized with ACS in the United States. The initial treatment has evolved over the last few decades from conservative management to early reperfusion therapy. Medical therapy has also significantly changed with the use of newer more potent antiplatelet agents, beta-blockers, angiotensin converting enzyme inhibitors, statins, and anti-anginal drugs, which have resulted in improvement of patient care and survival. There is no role for stress myocardial perfusion imaging (MPI) in the acute presentation; however, rest MPI may be used to identify the culprit lesion and risk stratify patients if injected during chest pain. In stable patients for ACS, submaximal exercise or vasodilator MPI can be performed as early as 48 hours after the event. Several gated MPI-derived variables such as left ventricular (LV) ejection fraction (EF), LV volumes, infarct size, mechanical dyssynchrony, and residual ischemic burden can risk stratify patients and provide prognostic data incremental to validated clinical risk scores such as GRACE (Global Registry of Acute Coronary Syndrome) and TIMI (Thrombolysis in Myocardial Infarction). Patients with depressed LVEF, remodeled LV, and large perfusion defects are at particularly high- risk for subsequent cardiac death or recurrent myocardial infarction. In such setting, MPI plays a pivotal role in the management of patients and guiding therapeutic decisions. The current chapter will review the clinical and MPI predictors of outcomes in patients presenting with ACS according to updated guidelines and a proposed algorithm integrating the role of MPI in guiding therapeutic decisions and management.
9
Ehrenreich-May, Jill, Sarah M. Kennedy, Jamie A. Sherman, Shannon M. Bennett, and David H. Barlow. Unified Protocol for Transdiagnostic Treatment of Emotional Disorders in Adolescents. Oxford University Press, 2017. http://dx.doi.org/10.1093/med-psych/9780190855536.001.0001.
Full textAbstract:
Unified Protocol for Transdiagnostic Treatment of Emotional Disorders in Adolescents: Workbook (UP-A) provides evidence-based treatment strategies to assist adolescent clients to function better in their lives. This treatment is designed for adolescents who are experiencing feelings of sadness, anxiety, worry, anger, or other emotions that get in the way of their ability to enjoy their lives and feel successful. The workbook is written for adolescents and guides them through each week of the program with education, activities, and examples that will help them to understand the role that emotions play in their behaviors every day. Adolescents are taught helpful strategies for dealing with uncomfortable emotions and will receive support in making choices that will move them closer to their long-term goals. The evidence-based treatment skills presented in the accompanying Therapist Guide may be applied by the therapist to adolescents with a wide variety of emotional disorders. The UP-A takes a transdiagnostic approach to the treatment of the emotional disorders. Some of the disorders that may be targeted include anxiety disorders (e.g., generalized anxiety disorder, social anxiety disorder, separation anxiety disorder, specific phobias, panic disorder, illness anxiety disorder, agoraphobia) and depressive disorders (e.g., persistent depressive disorder, major depressive disorder). This treatment is flexible enough for use with some trauma and stress-related disorders (including adjustment disorders), somatic symptom disorders, tic disorders, and obsessive-compulsive disorders. The transdiagnostic presentation of evidence-based intervention techniques within these treatments may be particularly useful for adolescents presenting with multiple emotional disorders or mixed/subclinical symptoms of several emotional disorders.
10
Kočka, Viktor, Steen Dalby Kristensen, William Wijns, Petr Toušek, and Petr Widimský. Percutaneous coronary interventions in acute coronary syndromes. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780199687039.003.0047_update_002.
Full textAbstract:
Three different guidelines of the European Society of Cardiology cover the field of percutaneous coronary interventions. Their main recommendations are the following: All patients with an ST-segment elevation myocardial infarction should undergo immediate coronary angiography and percutaneous coronary intervention as soon as possible after the first medical contact. Thrombolysis can be used as an alternative reperfusion therapy if the time delay to primary percutaneous coronary intervention is more than 2 hours. Patients with very high-risk non-ST-segment elevation acute coronary syndromes (recurrent or ongoing chest pain, profound or dynamic electrocardiogram changes, major arrhythmias, or haemodynamic instability) should undergo urgent coronary angiography within less than 2 hours after the initial hospital admissionAll moderate- to high-risk (GRACE score >140 or at least one primary high-risk criterion) non-ST-segment elevation acute coronary syndromes patients should undergo coronary angiography before discharge; the ideal timing is within 24 hours after admission for high-risk groups, and within 72 hours for moderate-risk groups. Other patients with recurrent symptoms or at least one high-risk criterion should undergo coronary angiography within 72 hours of first presentation. Low-risk non-ST-segment elevation acute coronary syndromes may be treated conservatively, and the indication for an invasive evaluation can be done, based on the evidence of ischaemia during exercise stress testing. Stents should be used during all percutaneous coronary intervention procedures, whenever technically feasible. Second-generation drug-eluting stents do not increase stent thrombosis and can be safely used in the ST-segment elevation myocardial infarction and non-ST-segment elevation acute coronary syndrome settings. Triple pharmacotherapy, consisting of aspirin, thienopyridine antiplatelet agent, and anticoagulation with heparin or bivalirudin, should be used in all percutaneous coronary intervention procedures, with glycoprotein IIb/IIIa inhibitors added in patients with a high thrombus burden and low bleeding risk.
Book chapters on the topic "Stress presentation mode"
1
Wittstein, Ilan. "Clinical presentation of takotsubo syndrome." In ESC CardioMed, 1288–94. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780198784906.003.0318.
Full textAbstract:
Takotsubo syndrome (TTS), also known as stress cardiomyopathy, left ventricular apical ballooning syndrome, and broken heart syndrome, is a syndrome of acute heart failure and transient ventricular dysfunction that is frequently precipitated by acute emotional or physical stress. A wide variety of emotional and physical stressors have been associated with this syndrome, and while acute stress is temporally related to syndrome onset in the majority of patients, a subset of patients have no identifiable antecedent trigger at the time of presentation. The syndrome has a striking predilection for older postmenopausal women, though it has been reported in men and in younger patients as well. The incidence of TTS is higher than initially thought and accounts for up to 5–10% of women presenting with a suspected acute coronary syndrome. Several groups have proposed variable criteria for the diagnosis of TTS, but universally accepted criteria are currently lacking. While patients with TTS typically present with chest pain, dynamic electrocardiographic changes, and elevated cardiac biomarkers, characteristic features of the syndrome that help to distinguish it from an acute myocardial infarction include the absence of plaque rupture and coronary thrombosis, unique patterns of ventricular dysfunction that typically involve more than one vascular territory, and rapid and complete recovery of ventricular systolic function. While the prognosis associated with TTS is generally favourable, the condition is not benign and has been associated with serious complications such as cardiogenic shock, thromboembolic events, and life-threatening arrhythmias. This chapter will highlight the clinical features that characterize TTS and that are central to its diagnosis.
2
Wittstein, Ilan. "Clinical presentation of takotsubo syndrome." In ESC CardioMed, 1288–94. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780198784906.003.0318_update_001.
Full textAbstract:
Takotsubo syndrome (TTS), also known as stress cardiomyopathy, left ventricular apical ballooning syndrome, and broken heart syndrome, is a syndrome of acute heart failure and transient ventricular dysfunction that is frequently precipitated by acute emotional or physical stress. A wide variety of emotional and physical stressors have been associated with this syndrome, and while acute stress is temporally related to syndrome onset in the majority of patients, a subset of patients have no identifiable antecedent trigger at the time of presentation. The syndrome has a striking predilection for older postmenopausal women, though it has been reported in men and in younger patients as well. The incidence of TTS is higher than initially thought and accounts for up to 5–10% of women presenting with a suspected acute coronary syndrome. Several groups have proposed variable criteria for the diagnosis of TTS, but universally accepted criteria are currently lacking. While patients with TTS typically present with chest pain, dynamic electrocardiographic changes, and elevated cardiac biomarkers, characteristic features of the syndrome that help to distinguish it from an acute myocardial infarction include the absence of plaque rupture and coronary thrombosis, unique patterns of ventricular dysfunction that typically involve more than one vascular territory, and rapid and complete recovery of ventricular systolic function. While the prognosis associated with TTS is generally favourable, the condition is not benign and has been associated with serious complications such as cardiogenic shock, thromboembolic events, and life-threatening arrhythmias. This chapter will highlight the clinical features that characterize TTS and that are central to its diagnosis.
3
Mehta, Puja K., Ijeoma Isiadinso, and L. Samuel Wann. "Stress Testing in Women." In Ellestad's Stress Testing, edited by Gregory S. Thomas, L. Samuel Wann, and Myrvin H. Ellestad, 473–91. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780190225483.003.0024.
Full textAbstract:
The chapter Stress Testing in Women reviews the clear sex-specific differences in the presentation and pathophysiology of ischemic heart disease (IHD). Women tend to have more atypical and more subtle symptoms such as dyspnea or fatigue than men. Symptomatic women are also more likely to have no obstructive coronary artery disease (CAD) on coronary angiography, but still have adverse clinical outcomes. Coronary microvascular dysfunction. Exercise testing is frequently the first test of choice to diagnose IHD in women. When resting electrocardiogram abnormalities precludes exercise testing or exercise testing is inconclusive, stress imaging with echocardiography or myocardial perfusion imaging can be added. Routine stress testing is designed to detect flow-limiting, obstructive CAD. When stress imaging is negative or “falsely positive” in a symptomatic patient, nonobstructive causes of IHD including coronary microvascular dysfunction should be considered.
4
McCarty, Richard. "Stress and Autism Spectrum Disorder." In Stress and Mental Disorders: Insights from Animal Models, 267–96. Oxford University Press, 2020. http://dx.doi.org/10.1093/med-psych/9780190697266.003.0009.
Full textAbstract:
Animal models of autism spectrum disorder (ASD) seek to capture three of the cardinal symptoms of the disorder in affected children: deficits in social interactions, deficits in communication, and repetitive behaviors. In addition, males are more likely to develop ASD than females. The complex and variable presentation of ASD appears to involve genetic, environmental, and epigenetic contributions. The inbred BTBR mouse strain has frequently been utilized as an animal model of ASD. Other animal models have included a variety of prenatal insults, including maternal immune activation or administration of drugs that affect the developing fetus. A newer line of investigation has examined contributions of the brain-immune-gut axis in the development of symptoms of ASD in laboratory mice. Finally, the polarity change of GABAergic neurons in the cerebral cortex from excitatory to inhibitory at birth appears to be connected to the surge in oxytocin, and this key developmental process may be disrupted in children with ASD and in animal models of ASD.
5
Deng, Lawrence Y., Huan-Chao Keh, and Yi-Jen Liu. "Ontology-Based Multimedia Authoring Tool for Adaptive E-Learning." In Intelligent Learning Systems and Advancements in Computer-Aided Instruction, 119–43. IGI Global, 2012. http://dx.doi.org/10.4018/978-1-61350-483-3.ch008.
Full textAbstract:
More video streaming technologies supporting distance learning systems are becoming popular among distributed network environments. In this paper, the authors develop a multimedia authoring tool for adaptive e-learning by using characterization of extended media streaming technologies. The distributed approach is based on an ontology-based model. Suppose a well-known teacher is giving a lecture/presentation to his student. Because of time constraints and other commitments, many students cannot attend. The main goal of the authors’ system is to provide a feasible method to record and represent a lecture/presentation using a browser with the windows media services. This system requires flexible support for the modeling of multimedia content models and supports possible interactivity, transfer of streams multimedia data such as audio, video, text, and annotations using network facilities. The authors propose a new approach for the modeling of reusable and adaptable multimedia content. A comprehensive system for advanced multimedia content production is also developed. This approach significantly impacts and supports the multimedia presentation authoring processes in terms of methodology and commercial aspects.
6
Knuuti, Juhani, and Antti Saraste. "Conclusions and recommendations." In ESC CardioMed, edited by Steen Kristensen, 2686–90. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780198784906.003.0650.
Full textAbstract:
This chapter provides a summary of pre- and perioperative assessment and management of patients with pre-existing cardiovascular disease undergoing non-cardiac surgery. More detailed presentations can be found in the preceding chapters in this section. An individualized, stepwise cardiac risk assessment protocol, integrating clinical risk indices and specific test results with the estimated stress of the planned surgical procedure is presented. For each step, evidence-based recommendations on medical therapy and cardiac interventions as well as considerations on surgical and anaesthetic techniques are presented in order to optimize the patient’s perioperative condition.
7
Johnson, E. Patrick. "I’m Alright with Who I Am." In Black. Queer. Southern. Women., 508–33. University of North Carolina Press, 2018. http://dx.doi.org/10.5149/northcarolina/9781469641102.003.0013.
Full textAbstract:
In this chapter, “Ida Mae” narrates her upbringing in Odenville, Alabama. She shares stories of experiencing childhood in a segregated town, being highly involved in the church, spending time at a local, Black, gay bar, and her family’s various reactions to her sexuality. In her narrative, she also stresses the importance of cross-dressing and experimenting with her gender presentation more often once she enrolled in college.
8
Leonor Botelho, Maria. "Oporto’s Historic Center." In Digital Cities, 172–84. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780190498900.003.0009.
Full textAbstract:
In 1996, the World Heritage Committee added the Historic Center of Oporto, Portugal, to the World Heritage List, recognizing its outstanding value, identified by its urban fabric and its many historic buildings. The area’s value is the result of a complex topography, articulated through streets, lanes, alleyways, stairs, and squares, while its architecture (residences and monuments) projects cultural values accumulated over successive eras. In the state of art section, this chapter presents some significant references and visual resources that contribute to the understand city´s urban development and to visualize the city in the past. This chapter presents two case studies of the authors’ attempts at visualization of that historic district. One describes a 3D scale model—Oporto’s Medieval Scale Model - and the other is a virtual reality project—Virtual Porto in the Sixteen Century—both shown as examples of thorough research, careful documentation of processes, and clear and approachable presentation. The authors also consider the potential of expanded development of such presentations, in light of uses in tourism and furthering greater knowledge, with the goals of facilitating the process of heritage conservation and the dissemination of information. As such, the two case studies are viewed in terms of principles of the London Charter regarding the creation of virtual heritage, as well as cite other examples of projects in European cities.
9
Morris, Reg C. "Psychological and emotional issues after stroke." In Stroke in the Older Person, 399–412. Oxford University Press, 2020. http://dx.doi.org/10.1093/med/9780198747499.003.0026.
Full textAbstract:
‘Psychological and emotional issues after stroke’ explores these symptoms in great detail. These symptoms are common, disabling, and increase the costs of healthcare. Psychological conditions can occur at any age, and a person’s age is just one of many factors to be considered when assessing, formulating, and treating these complications. The commonest and most salient psychological conditions after stroke are anxiety, depression, fatigue, and emotionalism. Other more subtle presentations include low self-esteem, low confidence, reduced self-efficacy, altered identity, and post-traumatic stress. In approaching psychological conditions, it is important to be mindful that most are not limited to the acute phase. The delivery of psychological care is not necessarily the domain of specialists alone; service models such as stepped care may engage a range of staff in helping with less severe presentations. The ubiquitous nature of psychological conditions requires approaches that enable large numbers to be assessed and treated cost-effectively. Group-based approaches and self-management are particularly important additions to resource-intensive one–to-one therapy.
10
Newton, Adam Zachary. "Mochlos or Makhlokes: JS and the Humanities." In Jewish Studies as Counterlife, 87–122. Fordham University Press, 2019. http://dx.doi.org/10.5422/fordham/9780823283958.003.0007.
Full textAbstract:
“Makhlokes” (Ashkenazi pronunciation) connotes “dissensus,” “separation,” “faction,” “dispute” (like German “Streit” in Kant’s Conflict of the Faculties). Its trilateral root חלק HLK can signify either “to divide” or “to be smooth or viscous.” How, in light of this Mishnaic concept, does JS position itself with respect to academic humanities: as a mode or leverage, or at a node of energetic conflict and contestation? A conservative, polemical answer to that question was posed thirty years ago by the late and prodigious scholar of rabbinic Judaism Jacob Neusner in several books about the disciplines, research methodologies, and modes of Jewish Studies in specific relation to the “new Humanities.” A wealth of reformulation has accrued to the latter term in the last decade or so. This chapter reopens and reorients Neusner’s presentation of the case vis-à-vis a contemporaneous deployment of the same term by Derrida.
Conference papers on the topic "Stress presentation mode"
1
Vogt, Jan, Thomas Schaaf, and Klaus Helbig. "Optimizing Lifetime Consumption and Increasing Flexibility Using Enhanced Lifetime Assessment Methods With Automated Stress Calculation From Long-Term Operation Data." In ASME Turbo Expo 2013: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/gt2013-95068.
Full textAbstract:
In the past most of the steam turbines were designed as base load machines. Due to new market requirements based on the effect of renewable energies, power plant operators are forced to operate with more frequent start-up events and load changes, resulting in a fundamental higher low cycle fatigue (LCF) lifetime consumption. Traditional methods of lifetime assessment often use representative start-ups, for the calculation of LCF damage, which can provide very conservative results with reasonable safety margins. For a high number of starts these safety margins may result in an overestimation of the LCF damage. At Alstom, an enhanced method for lifetime assessment has been developed, that evaluates the actual lifetime consumption from real operation data in an automated manner and provides much more realistic results. The operation data is used to calculate the transient temperature distribution and heat transfer coefficients along the rotor for each start-stop cycle. The corresponding stress distribution in the rotor is evaluated by means of a Finite-Element-method analysis. Finally the number of remaining cycles is extracted for the most critical locations using material data. In combination with the creep damage the lifetime consumption is evaluated. The entire process is highly automated, but also facilitates easy monitoring through the lifetime engineer by graphic presentation of calculation results. Using this enhanced method of lifetime assessment, the computed lifetime consumption is closer to the actual value, supporting the planning of overhauls and component replacements and minimizing the risk of failure or forced outages. The utilization of remaining lifetime can be optimized in favour of a more flexible mode of operation (e.g. low load operation and fast start-up) or extension of operational lifetime for conventional and combined cycle power plants.
2
Lee, Seung-Yub, Iuliana Cernatescu, and David U. Furrer. "Residual Stress Measurement Tools and Methods: Industrial View of Current Gaps and Opportunities." In HT2021. ASM International, 2021. http://dx.doi.org/10.31399/asm.cp.ht2021exabp0100.
Full textAbstract:
Abstract Residual stress measurement is necessary in several aspects of product development and sustainment: structural analysis of components, process quality validation, model development and validation, and understanding the root-cause of failure events. Especially in the aerospace industry, accurate residual stress assessment is critical due to the higher safety standards. However, limited tools and methods are available for different components and applications. Goal of this presentation is to review pros and cons of the various methods, discuss the technical challenges in stress determination, and introduce potential solutions to overcome the current limits.
3
Cherston, Juliana, and Joseph A. Paradiso. "Rotator: Flexible Distribution of Data Across Sensory Channels." In The 23rd International Conference on Auditory Display. Arlington, Virginia: The International Community for Auditory Display, 2017. http://dx.doi.org/10.21785/icad2017.009.
Full textAbstract:
‘Rotator’ is a web-based multisensory analysis interface that en- ables users to shift streams of multichannel scientific data between their auditory and visual sensory channels in order to better discern structure and anomaly in the data. This paper provides a technical overview of the Rotator tool as well as a discussion of the mo- tivations for integrating flexible data display into future analysis and monitoring frameworks. An audio-visual presentation mode in which only a single stream is visualized at any given moment is identified as a particularly promising alternative to a purely visual information display mode. Auditory and visual excerpts from the interface are available at http://resenv.media.mit.edu/rotator.
4
Chen, Minyou, Yongjian Wan, Fan Wu, Kaigui Xie, Mingyu Wang, and Bin Fan. "A neural-fuzzy model with confidence measure for controlled stressed-lap surface shape presentation." In 4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Advanced Optical Manufacturing Technologies, edited by Li Yang, John M. Schoen, Yoshiharu Namba, and Shengyi Li. SPIE, 2009. http://dx.doi.org/10.1117/12.831065.
Full text
5
Herter, Karl-Heinz, Xaver Schuler, and Michael Seidenfuss. "Strain Limits for the Analysis of the Mechanical Behaviour of Pressurized Components." In ASME 2012 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/pvp2012-78752.
Full textAbstract:
In technical codes and standards the strength assessment of pressurized components and systems is usually performed by limitation of fictitious elastic stresses as well as by limitation of the fatigue level. It shall be proven that the highest stresses resp. stress ranges caused by external loading show a specific margin against the resistance of the material used (concept of stress limitation). This concept is based on the principle that in a component with inhomogeneous stress distribution plastic deformation are allowed at the locations which sustain the highest loads. If in special cases the stress categorization is unclear, the effect of plastic deformation on the mechanical behavior shall be decisive. The same holds for postulated load levels with low occurrence probability (severe accidents) for which the stress limits do not utilize fully the deformation capacity of ductile materials. For that reason solutions that are based on the “Strain Limitation Concept” (SLC) shall be developed. Strength assessment using the concept of strain limitation relies on limiting strains to a specified allowable strain value, i.e. “Limit Strain Curve” (LSC). Within this presentation the approach of the concept of strain limitation is described with a special attention for the determination of the strain limits that can be allowed. With the help of Finite Element damage calculations (Rousselier model) on notched round bars the deformation behavior of an austenitic steel is described until failure. The dependency of the local failure strain on size, stress triaxiality and stress gradients is analyzed. In order to validate the numerical investigation these results are compared with experiments.
6
Habean, Stefan, Justin Sims, Zhichao Li, and B. Lynn Ferguson. "Quenching Process Improvement Through Modeling." In HT2019. ASM International, 2019. http://dx.doi.org/10.31399/asm.cp.ht2019p0329.
Full textAbstract:
Abstract Computer modeling offers an excellent method to investigate heat treatment processes, especially processes that have quality issues, that are open to use of different alloys, or that are under development.[1-4] A recent presentation from Karlsruhe Institute of Technology[5] was an excellent example of this, where three variations of a novel tube quenching process showed experimental evidence that two of the processes resulted in tubes with cracks on the bore while the third process produced crack-free parts. Interested in investigating this in more detail using computer modeling, a study was initiated to investigate additional process variations to better understand the effect of quenching conditions on stresses and microstructural evolution in the part. With a goal of producing martensite and residual compressive stress in the bore of a 4140 steel tube, a matrix of hardening processes was developed and executed. Models examined heat transfer and also microstructural evolution, i.e. phase transformation kinetics. Results showed that the timing and rate of martensite formation, and bainite kinetics had a significant effect on both the in-process stress state and the residual stress state.
7
Bamford, Warren. "Section XI: Responding to Inservice Inspection Findings." In ASME 2003 Pressure Vessels and Piping Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/pvp2003-1803.
Full textAbstract:
As plants continue to age, modes of degradation are found that had not been anticipated as part of the design process. One of the most important modes of degradation found recently has been stress corrosion cracking. This presentation will deal with three examples of such cracking for which acceptance criteria and evaluation methodology are being developed for Section XI. These three include: • Class 1 piping; • Reactor Vessel Head Penetration Cracking (PWR only); • Low Energy Piping, Vessels and Tanks.
8
Williams, Dara. "Calibration of Stress Transfer Functions for Wellhead Fatigue." In ASME 2015 34th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/omae2015-41488.
Full textAbstract:
In many harsh environment or high current regions (e.g. West of Shetlands, East Africa and GoM) wellhead fatigue during drilling or workover activities can be a major concern. As a result extensive wellhead and conductor fatigue assessments are required in order to predict likely fatigue damage prior to landing the BOP on to the wellhead. These pre-drilling or predictive studies are based on a number of assumptions regarding actual environmental and soil conditions. In addition the uncertainty associated with the input data requires safety factors of 10 and 20 for wave and VIV effects respectively. As a result of these assumptions the predicted levels of fatigue damage to the wellhead may be highly conservative. In cases where wellhead and conductor fatigue life is a concern the operator may choose to deploy motion monitoring systems on the BOP stack so that actual fatigue loads recorded during drilling can be calculated. These systems can be configured to provide ‘real-time’ updates on fatigue damage accumulation or can be used to record data for ‘post-drilling’ assessment. In each case the methodology applied to calculate stresses at fatigue hotspots is critical to the calculation of overall fatigue damage. The calculation of fatigue loads based on measured data is typically carried out by applying the measured BOP motions to a global finite element model of the drilling riser and wellhead system. However due to the large amounts of data involved this can be a very time consuming exercise and is not conducive to ‘real-time’ presentation of results (e.g. for on-board systems). A proposed solution to this problem is to develop stress transfer functions (STFs) that relate BOP motion to stresses at critical fatigue hotspots. Thus ‘real-time’ BOP motions and be instantly converted to ‘real-time’ stresses. However, as is outlined in this paper, the frequency content of the system response can have a significant impact on the levels of stress calculated. If frequency dependent response is not accounted for a significant under-prediction in fatigue loads may occur. The objective of this paper is to outline a detailed methodology to derive STFs for critical fatigue hotspots in the wellhead and conductor. This methodology accounts for capturing the non-linear frequency dependence of the system and incorporating this into the STFs. In addition a methodology for rapidly calculating ‘real-time’ fatigue damage accumulation in the wellhead and conductor system and presenting this data on-board is also outlined.
9
Afshar, Sepideh, Imran Rizvi, and Walfre Franco. "Estimation of permeability from optical observations in a model system of 3D ovarian cancer nodules subjected to fluidic shear stress (Conference Presentation)." In Microfluidics, BioMEMS, and Medical Microsystems XVII, edited by Bonnie L. Gray and Holger Becker. SPIE, 2019. http://dx.doi.org/10.1117/12.2510089.
Full text
10
Johnsen, Roy, Ba˚rd Nyhus, and Stig Wa¨stberg. "Hydrogen Induced Stress Cracking (HISC) of Stainless Steels Under Cathodic Protection in Seawater: Presentation of a New Test Method." In ASME 2009 28th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/omae2009-79325.
Full textAbstract:
There has been an increasing trend in the use of stainless steel alloys instead of carbon steel for subsea flowlines and production systems during the last 15 years in the oil industry. Even if this normally is a more robust solution compared to the use of carbon steel insofar as internal corrosion problems are concerned, the use of stainless steels has led to leakage, production shutdown and expensive repair work. The reported failures were associated with hydrogen entrapment resulting from welding and/or external cathodic protection (CP), combined with a certain stress/strain level. Atomic hydrogen entering the alloy can weaken the mechanical strength of the alloy, cause cracks and destroy the integrity of equipment or a system. Such failures attributed to hydrogen induced stress cracking (HISC) are clearly not acceptable from the perspective of safety, environmental hazard and cost. Leading oil and engineering companies and supplier industry have pointed out HISC as one of the major obstacles against safe operation of stainless steel subsea pipelines and production systems. It is important for the oil industry to have design guidelines and reliable test method(s) for qualification and safe utilization of subsea pipelines and components made from the actual stainless steels. This paper describes a test method that has been developed through a Joint Industry Project (JIP) executed by SINTEF and Det Norske Veritas (DNV) with support from leading oil companies and material suppliers. The method has been qualified for use on 13% Cr super martensitic (SMSS) and 22% Cr / 25% Cr duplex stainless steels (DSS/SDSS). The link to DNV-RP-F112 [1] will also be described.