scholarly journals Estimation of the Damping Parameter Governing the VIV of Long Flexible Cylinders

2015 ◽  
Author(s):  
Zhibiao Rao ◽  
J. Kim Vandiver
Keyword(s):  
Full Range ◽  
Primary Objective ◽  
Response Data ◽  
Past Half Century ◽  
Damping Parameter ◽  
Exploration And Production ◽  
Spatially Varying ◽  
Production Company ◽  
Synchronized Region

Much effort in the past half century has been made to explain the role of damping in the prediction of VIV. Scruton (1965), Griffin et al. (1975), Klamo, et al. (2005) and Govardhan & Williamson (2006) all made significant contributions. None fully characterized the role of damping in governing the response over the full range reduced velocities, which encompass the wake synchronized region. In 2012 Vandiver devised a way to do that with a new damping parameter c*. His results were verified using 2D spring-mounted cylinders in uniform flow. The primary objective of the research described in this paper is to find a c* -like quantity for flexible cylinders, which is capable of organizing response data for flexible cylinders, which may have many modes, be exposed to sheared flows and possess spatially varying properties, such as the coverage of strakes and fairings. Data from a recent high mode VIV model test campaign conducted by SHELL Exploration and Production Company are used to illustrate the application of c* to flexible cylinders. It is shown that, if one accounts for Reynolds number, the response of flexible cylinders with varying strake coverage in the SHELL Tests collapse onto a single curve.

On the Role of Marangoni Effects on the Critical Heat Flux for Pool Boiling of Binary Mixtures

1996 ◽  
Vol 118 (1) ◽  
pp. 103-109 ◽  
Author(s):  
W. R. McGillis ◽  
V. P. Carey
Keyword(s):  
Surface Tension ◽  
Heat Flux ◽  
Binary Mixtures ◽  
Critical Heat Flux ◽  
Full Range ◽  
Pool Boiling ◽  
Marangoni Effect ◽  
Restoring Force ◽  
Marangoni Effects

The Marangoni effect on the critical heat flux (CHF) condition in pool boiling of binary mixtures has been identified and its effect has been quantitatively estimated with a modified model derived from hydrodynamics. The physical process of CHF in binary mixtures, and models used to describe it, are examined in the light of recent experimental evidence, accurate mixture properties, and phase equilibrium revealing a correlation to surface tension gradients and volatility. A correlation is developed from a heuristic model including the additional liquid restoring force caused by surface tension gradients. The CHF condition was determined experimentally for saturated methanol/water, 2-propanol/water, and ethylene glycol/water mixtures, over the full range of concentrations, and compared to the model. The evidence in this study demonstrates that in a mixture with large differences in surface tension, there is an additional hydrodynamic restoring force affecting the CHF condition.

scholarly journals Decision Making from the Experience of Orthognathic Surgery Patients: A Grounded Theory Approach

2021 ◽  
pp. 238008442110144
Author(s):  
N.R. Paul ◽  
S.R. Baker ◽  
B.J. Gibson
Keyword(s):  
Decision Making ◽  
Grounded Theory ◽  
Treatment Options ◽  
Study Data ◽  
Primary Objective ◽  
Major Surgery ◽  
Future Research ◽  
Decision Making Process ◽  
Theory Approach

Introduction: Patients’ decisions to undergo major surgery such as orthognathic treatment are not just about how the decision is made but what influences the decision. Objectives: The primary objective of the study was to identify the key processes involved in patients’ experience of decision making for orthognathic treatment. Methods: This study reports some of the findings of a larger grounded theory study. Data were collected through face-to-face interviews of patients who were seen for orthognathic treatment at a teaching hospital in the United Kingdom. Twenty-two participants were recruited (age range 18–66 y), of whom 12 (male = 2, female = 10) were 6 to 8 wk postsurgery, 6 (male = 2, female = 4) were in the decision-making stage, and 4 (male = 0, female = 4) were 1 to 2 y postsurgery. Additional data were also collected from online blogs and forums on jaw surgery. The data analysis stages of grounded theory methodology were undertaken, including open and selective coding. Results: The study identified the central role of dental care professionals (DCPs) in several underlying processes associated with decision making, including legitimating, mediating, scheduling, projecting, and supporting patients’ decisions. Six categories were related to key aspects of decision making. These were awareness about their underlying dentofacial problems and treatment options available, the information available about the treatment, the temporality of when surgery would be undertaken, the motivations and expectation of patients, social support, and fear of the surgery, hospitalization, and potentially disliking their new face. Conclusion: The decision-making process for orthognathic treatment is complex, multifactorial, and heavily influenced by the role of DCPs in patient care. Understanding the magnitude of this role will enable DCPs to more clearly participate in improving patients’ decision-making process. The findings of this study can inform future quantitative studies. Knowledge Transfer Statement: The results of this study can be used both for informing clinical practice around enabling decision making for orthognathic treatment and also for designing future research. The findings can better inform clinicians about the importance of their role in the patients’ decision-making process for orthognathic treatment and the means to improve the patient experience. It is suggested that further research could be conducted to measure some of the key constructs identified within our grounded theory and assess how these change during the treatment process.

Cocaine use, abuse and dependence in a population-based sample of female twins

1998 ◽  
Vol 173 (4) ◽  
pp. 345-350 ◽  
Author(s):  
Kenneth S. Kendler ◽  
Carol A. Prescott
Keyword(s):  
Cocaine Abuse ◽  
Genetic Factors ◽  
Model Fitting ◽  
Population Based ◽  
Cocaine Use ◽  
Past Half Century ◽  
History Of ◽  
Population Based Registry ◽  
Twin Resemblance

BackgroundAlthough cocaine use in women has increased substantially over the past half-century, we understand little about the aetiology in women of cocaine use and abuse, and know almost nothing about the role of genetic factors.MethodWe obtained by telephone interview a history of lifetime cocaine use, abuse and dependence from 1934 individual twins from female–female pairs ascertained through a population-based registry, including both members of 485 monozygotic (MZ) and 335 dizygotic (DZ) pairs.ResultsThe prevalence of lifetime cocaine use, abuse and dependence were 14.0%, 3.3% and 2.3%. Probandwise concordance rates, in MZ and DZ twins, respectively, were: cocaine use 54% and 42%; cocaine abuse 47% and 8% and cocaine dependence 35% and 0%. In MZ and DZ twins, odds ratios were: cocaine use 14.2 and 6.7 and cocaine abuse 40.8 and 2.7. Biometrical model-fitting suggested that twin resemblance for liability to cocaine use was due to both genetic and familial–environmental factors while twin resemblance for cocaine abuse and symptoms of dependence was due solely to genetic factors. Estimated heritabilities were: cocaine use 0.39, cocaine abuse 0.79 and symptoms of dependence 0.65.ConclusionsThe vulnerability to cocaine use and particularly cocaine abuse and dependence in women is substantially influenced by genetic factors.

Senior nurse role expectations of graduate registered and enrolled nurses on commencement to practice

2014 ◽  
Vol 38 (4) ◽  
pp. 432 ◽  
Author(s):  
Elisabeth R. Jacob ◽  
Lisa McKenna ◽  
Angelo D'Amore
Keyword(s):  
Registered Nurses ◽  
Nursing Care ◽  
Online Survey ◽  
Full Range ◽  
Role Expectations ◽  
Graduate Nurse ◽  
Senior Nurse ◽  
Nurse Role ◽  
Role Confusion

Objective This paper reports on a project to examine the expectations of senior nurses regarding graduate roles of registered and enrolled nurses educated in Victoria, Australia. Methods Participants completed an online survey to indicate whether predetermined competencies were in the roles of graduate enrolled or registered nurses or not in the role of either nurse. Chi-squared analysis was used to identify differences between participant groups. Results Participants expressed variations in role expectations for the different level of graduate nurse. Although basic nursing care was undertaken by both graduate enrolled and registered nurses, no specific role was identified for enrolled nurses. Differences were found in the opinions of senior nurses over the roles of graduate nurses, demonstrating considerable variation in expectations. Management, education and research roles were not identified as the role of either nurse on graduation. Differences were found in the expectations of the different senior nurse groups regarding the roles of the enrolled nurse, particularly in the new skills taught in the enrolled nurse diploma program. Conclusions Confusion exists regarding the roles of both types of nurse on graduation. Further research across Australia is required to clarify the roles of the different level of nurse in different practice contexts. What is known about the topic? Australia, like many other countries, prepares two levels of nurse for entry to practice: the degree-prepared registered nurse and the diploma-prepared enrolled nurse. Role confusion and ambiguity have been reported in the literature by many countries, including Australia, that employ two levels of nurse. What does this paper add? Great variation exists between expectations of senior nursing staff as to the role of both levels of graduate nurse. Role confusion and ambiguity exists for nurses in Australia. Role confusion and ambiguity around the scope of practice for enrolled nurses is seen as both limiting their practice and encouraging them to work at levels for which they have not been prepared. Graduate registered nurses were seen as more prepared for required graduate attributes than enrolled nurses. Care of acute, complex or deteriorating patients remains the role of registered nurses. What are the implications for practitioners? Practising nurses need to be educated as to the skills and knowledge that diploma enrolled nurses are graduating with in order to enable them to use their full range of abilities. To provide safe, quality care, registered nurses must fully understand the roles and abilities of the enrolled nurses to whom they delegate care. Organisational health policies and procedures need to be reviewed to accommodate the increased skills and knowledge of diploma-prepared enrolled nurses and enable best utilisation of their skills. Practising nurses need to be aware that enrolled nurses are not educationally prepared to care for complex or deteriorating patients. Although they are able to undertake basic nursing care, the role of caring for complex, highly acute and deteriorating patients remains in the domain of registered nurses. The increasing acuity of patients admitted to health services requires a higher skill mix of registered nurses to safely care for them.

scholarly journals Adaptations in traditional courtyard houses in Baghdad, Iraq

2017 ◽  
Vol 35 (4) ◽  
pp. 348-363 ◽  
Author(s):  
Rand H.M. Agha ◽  
John M. Kamara
Keyword(s):  
Design Methodology ◽  
Full Range ◽  
Physical Structure ◽  
Structured Interviews ◽  
Content Type ◽  
Case Study Analysis ◽  
Physical Spaces ◽  
Adaptation Model

Purpose The purpose of this paper is to investigate the adaptations that have been made to traditional courtyard houses (TCHs) in Baghdad, Iraq. The aim is to develop an understanding of various factors in the adaptation of these buildings to suit contemporary lifestyles, which will contribute to the wider field of building adaptability. Design/methodology/approach Empirical evidence was collected through case studies of 12 TCHs in the Al-Kadhimiya area of Baghdad, which involved a physical survey of buildings and semi-structured interviews with 24 occupants. Findings Case study analysis show that building adaptability involves both a change to physical spaces and also to lifestyles; with the latter being more likely when there are limitations in how much change can be made to the physical structure. Research limitations/implications The focus of this research is mainly on users’ adaptation of spaces and therefore does not consider the full range of stakeholders involved in the adaptation process. The findings also only apply to the cases considered and may not be applicable to other house types or locations. Originality/value Studies on building adaptability mostly focus on the ease of change to the building fabric, although the role of users is acknowledged. This study provides insights into the complexity and variety of changes that users can make, which are influenced by lifestyles and driven by the need for comfort. These insights are represented in an adaptation model, which can serve as a basis for further research.

The Role of Serotonin in the Development of Psychiatric Disorders: Studies on Drug Dependence and Anxiety-like Behaviour Following the Genetic Reduction of the Serotonin Transporter

2021 ◽  
Author(s):  
◽  
Alana Oakly
Keyword(s):  
Psychiatric Disorders ◽  
Early Development ◽  
Drug Dependence ◽  
Primary Objective ◽  
Behavioural Response ◽  
Mrna Levels ◽  
Self Administration ◽  
Knock Out ◽  
Enhanced Sensitivity

<p>Rationale: Given the high prevalence and large burden of psychiatric disorders it is imperative to determine the underling etiology in order for better understanding and treatment. The neurotransmitter serotonin (5-HT) has been associated with mental disorders in humans both pharmacologically and genetically. Individuals with the short-allele of a prominent polymorphism within the 5-HT transporter (SERT) show increased incidence of mood disorders and drug dependence. However, whether or not dysregulation in the 5-HT system causes, or is just associated with, psychiatric disorders is impossible to determine from human studies alone. Consequently, it is imperative to employ an animal model of down-regulated SERT function. To better understand the role of 5-HT in drug dependence, the rat’s behavioural response to the psychostimulant (±) 3, 4-methylenedioxymethamphetamine (MDMA), a preferentially serotonergically mediated drug, was assessed. Finally, the ability to rescue the anxiety-like phenotype in the SERT-/- rat by altering extracellular 5-HT during early development was also evaluated.  Objective: The primary objective of the current thesis was to determine whether dysregulation of 5-HT is directly linked to the occurrence of psychiatric disorders, particularly drug dependence and anxiety.  Methods: A model of down-regulated SERT function, the SERT knock-out (SERT-/-) rat, was used for all experiments in order to determine a causal relationship between 5-HT dysregulation and psychiatric disorders. In Chapter 2, the response of the SERT-/- rats to various tasks usually disrupted by MDMA was assessed. In Chapter 3, the sensitivity of the SERT-/- rats to the reinforcing effects of MDMA was determined using the self-administration paradigm. Finally, in Chapter 4, whether the anxiety-like behaviour of the SERT-/- rat could be rescued through normalising excessive extracellular 5-HT neonatally was assessed. An attempt was also made to determine a mechanism by which 5-HT dysregulation could alter behaviour. To this end, gene expression previously found to be up- or down-regulated in the SERT-/- rat was assessed in the neonatally treated rats.  Results: The results of Chapter 2 indicated the SERT is necessary for MDMA’s disruption of startle habituation but not its psychomotor effects. Moreover, for those rats that could discriminate low dose MDMA from saline, genetic removal of the SERT resulted in the inability to discriminate MDMA from amphetamine, implying that, in these rats, MDMA was now subjectively indistinguishable from amphetamine. Indeed, this alteration also resulted in enhanced sensitivity to the reinforcing properties of MDMA, giving MDMA the qualities of a traditional psychostimulant in SERT-/- rats (Chapter 3). Finally, lowering the excessive 5-HT during neonatal development in SERT-/- rats led to a rescue of mild, but not high, anxiety-like behaviour in males. However, mRNA levels of long 3’NTR BDNF and 5-HT1a, genes associated with neurodevelopment, remained unchanged across genotypes and treatment groups (Chapter 4).  Conclusions: Genetic removal of the 5-HT transporter results in an altered behavioural response to MDMA, in particular an increased sensitivity to its reinforcing properties. However, while the genetic removal of the SERT results in enhanced extracellular 5-HT, the pathological phenotypes present in this rat are likely due to this increase occurring in early development, not its continued presence in adulthood. Overall, these findings contribute to the growing body of literature indicating that enhanced brain 5-HT during early development can lead to pathological behaviour in adulthood.</p>

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