Analytical Formulation of the Jacobian Matrix for Non-linear Calculation of the Forced Response of Turbine Blade Assemblies with Wedge Friction Dampers

A fundamental issue in turbomachinery design is the dynamical stress assessment of turbine blades. In order to reduce stress peaks in the turbine blades at engine orders corresponding to blade natural frequencies, friction dampers are employed. Blade response calculation requires the solution of a set of non-linear equations originated by the introduction of friction damping. Such a set of non-linear equations is solved using the iterative numerical Newton-Raphson method. However, calculation of the Jacobian matrix of the system using classical numerical finite difference schemes makes frequency domain solver prohibitively expensive for structures with many contact points. Large computation time results from the evaluation of partial derivatives of the non-linear equations with respect to the displacements. In this work a methodology to compute efficiently the Jacobian matrix of a dynamic system having wedge dampers is presented. It is exact and completely analytical. The proposed methods have been successfully applied to a real intermediate pressure turbine (IPT) blade under cyclic symmetry boundary conditions with underplatform wedge dampers. Its implementation showed to be very effective, and allowed to achieve relevant time savings without loss of precision

Mental health patients\u27 experiences of being misunderstood

Mental health patients describe “being understood” as an experience that evokes feelings of importance, worthiness, and empowerment. However, the experience of “being misunderstood” is more prevalent in patients’ relationships with health care providers. Negative consequences such as vulnerability, dehumanization, and frustration reveal that being misunderstood has the potential to damage or destroy therapeutic relationships

Take my hand, help me out: Mental health recipients\u27 experience of the therapeutic relationship

The purpose of this study was to describe mental health service recipients\u27 experience of the therapeutic relationship. The research question was ‘what is therapeutic about the therapeutic relationship?’ This study was a secondary analysis of qualitative interviews conducted with persons with mental illness as part of a study of the experience of being understood. This secondary analysis used data from 20 interviews with community-dwelling adults with mental illness, who were asked to talk about the experience of being understood by a health-care provider. Data were analysed using an existential phenomenological approach. Individuals experienced therapeutic relationships against a backdrop of challenges, including mental illness, domestic violence, substance abuse, and homelessness. They had therapeutic relationships with nurses (psychiatric/mental health nurses and dialysis nurses), physicians (psychiatrists and general practitioners), psychologists, social workers, and counsellors. Experiences of the therapeutic relationship were expressed in three figural themes, titled using participants\u27 own words: ‘relate to me’, ‘know me as a person’, and ‘get to the solution’. The ways in which these participants described therapeutic relationships challenge some long-held beliefs, such as the use of touch, self-disclosure, and blunt feedback. A therapeutic relationship for persons with mental illness requires in-depth personal knowledge, which is acquired only with time, understanding, and skill. Knowing the whole person, rather than knowing the person only as a service recipient, is key for practising nurses and nurse educators interested in enhancing the therapeutic potential of relationships

How patients and nurses experience the acute care psychiatric environment

The concept of the therapeutic milieu was developed when patients’ hospitalizations were long, medications were few, and oneto- one nurse–patient interactions were the norm. However, it is not clear how the notion of ‘therapeutic milieu’ is experienced in American acute psychiatric environments today. This phenomenological study explored the experience of patients and nurses in an acute care psychiatric unit in the USA, by asking them, ‘What stands out to you about this psychiatric hospital environment?’ Three figural themes emerged, contextualized by time, which was a source of stress to both groups: for patients there was boredom, and for nurses, pressure and chaos. Although they shared some themes, nurses and patients experienced them differently. For instance, nurses felt caged-in by the Plexiglas-enclosed nursing station, and patients felt caged-in by the locked doors of the unit. The findings from this US study do not support the existence of the therapeutic milieu as described in the literature. Furthermore, although the nurse–patient relationship was yearned for by nurses, it was nearly absent from patients’ descriptions. The caring experienced by patients was mainly derived from interactions with other patients

Authors\u27 and editors\u27 perspectives on peer review quality in three scholarly nursing journals

This study examined the quality of peer review in three scholarly nursing journals from the perspectives of authors and editors. Specifically, the study examined the extent to which manuscript reviews provided constructive guidance for authors to further develop their work for publication, and for editors to make informed and sound decisions on the disposition of manuscripts

Explosion models for thermonuclear supernovae resulting from different ignition conditions

We have explored in three dimensions the fate of a massive white dwarf as a function of different initial locations of carbon ignition, with the aid of a SPH code. The calculated models cover a variety of possibilities ranging from the simultaneous ignition of the central volume of the star to the off-center ignition in multiple scattered spots. In the former case, there are discussed the possibility of a transition to a detonation when the mean density of the nuclear flame decreases below 2x10**7 g cm**-3, and its consequences. In the last case, the dependence of the results on the number of initial igniting spots and the chance of some of these models to evolve to the pulsating delayed detonation scenario are also outlined.Comment: 5 pages, 1 figure, proceedings of IAU Colloquium 192, 'Supernovae (10 years of SN1993J)', 22-26 April 2003, Valencia, Spai

Impact of Credit on the Relative Well?Being of Women: Evidence from the Grameen Bank

summary This study examines the impact of credit on women's relative well?being in Grameen Bank's credit programmes. Using a bargaining model of the household, as extended by Amartya Sen, well?being has been defined in terms of three sets of capabilities: (i) autonomy, (ii) control over decision?making within the family, and (iii) relative access to household resources. It is hypothesised that the relative well?being of women and men depends on their respective bargaining power, which in turn depends on three factors: breakdown position, perceived contribution to the family and perceived self?interest. The hypothesis has been tested using a two?stage estimation method to avoid the potential problem of simultaneity bias that may be caused by the self?selection problem. Results indicate that involvement in credit has improved the relative well?being of women in some dimensions, but not in others. Some reasons are advanced for this partial success in improving women's well?being

Effects of lithium on electrical activity and potassium ion distribution in the vertebrate central nervous system

Three different regions of the vertebrate central nervous system maintained in vitro (frog spinal cord, guinea pig olfactory cortex and hippocampus) have been used to investigate how Li+ influences membrane potential, membrane resistance, action potentials, synaptic potentials and the transmembrane K+-distribution of neurons and glial cells. In view of the therapeutic action of Li+ in manicdepressive disease, a special effort was made to determine the threshold concentration for the actions of Li+ on the parameters described above. It was observed that Li+ induced a membrane depolarization of both neurons and glial cells, a decrease of action potential amplitudes, a facilitation of monosynaptic excitatory postsynaptic potentials and a depression of polysynaptic reflexes. The membrane resistance of neurons was not altered. Li+ also induced an elevation of the free extracellular potassium concentration and a decrease of the free intracellular potassium concentration. Furthermore, in the presence of Li+ a slowing of the recovery of the membrane potential of neurons and glial cells, and of the extracellular potassium concentration after repetitive synaptic stimulation was observed. The threshold concentrations for the effects of Li+ were below 5 mmol/l in the frog spinal cord and below 2 mmol/l in the guinea pig olfactory cortex and hippocampus. The basic mechanism underlying the action of Li+ may be an interaction with the transport-function of the Na+/K+ pump

Ballplayer or barrier breaker? Branding through the seven statues of Jackie Robinson

Jackie Robinson is the baseball player most frequently depicted by a public statue within the USA, a ubiquity explained by his unique position as barrier breaker of the Major League colour bar. Utilising a detailed inspection of statue designs, locations and inscriptions, and comparisons with wider baseball statuary, Robinson's monuments reveal a distinctive set of cultural projections. These are commemorations distinguished by their age, location away from MLB ballparks, lack of action poses and their use of inscriptions consisting of platitudes or discourse on the subject's relationship with the statue's location as opposed to athletic achievement. Such characteristics indicate that Jackie Robinson statues neither fulfil the typical role of branding host communities through nostalgia and reflected glory nor that of reparations. Instead, Robinson's statues act as mediators of reflected character and as tolerance branding. By projecting the softer aspects of Robinson's personality, and promoting a local history of racial tolerance as much as Robinson's triumph over wider intolerance, the host communities are seeking to identify themselves with these twin positive attributes. However, in neglecting a visual connection with baseball in the design and interpretative material, Robinson's statuary marginalises the relationship between his ability as a sportsman and his wider social impact

Changes of intracellular sodium and potassium ion concentrations in frog spinal motoneurons induced by repetitive synaptic stimulation

A post-tetanic membrane hyperpolarization following repetitive neuronal activity is a commonly observed phenomenon in the isolated frog spinal cord as well as in neurons of other nervous tissues. We have now used double-barrelled Na+- and K+-ion-sensitive microelectrodes to measure the intracellular Na+- and K+-concentrations and also the extracellular K+-concentration of lumbar spinal motoneurons during and after repetitive stimulation of a dorsal root. The results show that the posttetanic membrane hyperpolarization occurred at a time when the intracellular [Na+] reached its maximal value, intracellular [K+] had its lowest level and extracellular [K+] was still elevated. The hyperpolarization was blocked by ouabain and reduced by Li+. These data support the previous suggestion that an electrogenic Na+/K+ pump mode may be the mechanism underlying the post-tetanic membrane hyperpolarization