Inertia welding nickel-based superalloy: Part II. Residual stress characterization

The next generation of Ni-based alloys for aeroengines are richer in γ′ than existing alloys and are more difficult to weld by conventional means. Inertia welding is currently being developed as a joining technique for these alloys. Steep microstructural gradients have been observed in nickel-based superalloy RR1000 tube structures welded by inertia friction welding,^[1] and in this article, the concomitant residual stresses are mapped at depth using neutron diffraction. One tube in the aswelded and two in the postweld heat-treated (PWHT) condition have been investigated. In the case of the as-welded specimen, it was necessary to establish the variation of the stress-free lattice parameter, a ₀, across the weld line to infer elastic strain from lattice spacing changes. A biaxial sin² ψ measurement on thin slices was used to determine a ₀ as a function of the axial position from the weld line. This was in excellent agreement with the variation inferred by imposing a stress balance on the axial measurements. The change of a ₀ across the weld line can be rationalized in terms of the observed variation in the element partitioning effect between the matrix (γ) and the precipitates (γ′). It was found that the residual stresses in the weld and heat-affected zone generated by the welding process are large, especially close to the inner diameter of the welded ring. The experimental results have shown that, in order to relax the residual stresses sufficiently, the heat-treatment temperature must be increased by 50 °C over the conventional heat-treatment temperature. This is due to the high γ′ content of RR1000.     

Psychogenic stress: theory, experiment, practice

Experiments on animals (rodents, beasts, primates) and observation in man have ascertained that psychogenic stress is the most important defensive state of living organisms, which is constantly involved in order to maintain their interaction with external psychogenic factors. Three types of stress should be distinguished, these include normostress, hypostress, and hyperstress. Normostress has definite limits within which optimal responses, which are typical for an individual are realized. Hyperstress develops as a defensive response to extremely strong (extraordinary) stimuli. Hypostress can be observed in the retarded development of self-regulation mechanisms. All three types of stress are provided by a fundamental property of living organisms--the self-regulation mechanism, which realizes the keeping back of normostress constancy, or return of hyper- and hypostress to the normostress status. And only if an extreme deficit of self-regulation mechanisms takes place, hyper(hypo)stress could become a condition for the development of pathology.     

Factors influencing treatment planning of restorative dentistry in general practice: Part 2

This is the second of a short series of articles detailing the steps that a general dental practitioner should take in order to produce an effective treatment plan for each patient. In this article the various aspects of managing the patient and the examination are discussed.     

Occlusion and restorative dentistry: Part 1

Dentists are responsible for the health of the masticatory system--the musculature, temporomandibular joints, and the dentition. The influence of occlusion in restorative dentistry would appear to be directly proportional to the complexity of the treatment. The criteria of a mutually protected and optimum occlusion provide sets of sound guidelines for analysis of the occlusion and for subsequent procedures. In occlusal analysis, it is important to record the several characteristics of mandibular movements made during "empty mouth" movements, and later treat when necessary, because these movements can be more damaging to the masticatory system than mastication of food.     

Empirically supported interventions and school psychology: Conceptual and practice issues—Part II.

In Part II of this 2-part article (Part I, see record 2000-03347-005), the authors present some conceptual and practice issues on the use of empirically supported interventions in school and community settings. Conceptual issues discussed include the foci of effective intervention studies, specification of interventions, and intervention manuals and procedural guidelines. The authors conclude with a discussion of essential practice issues, given a dual goal of advancing research in empirically supported interventions and of producing a knowledge base that has a direct meaning and application to school and community settings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Self-in-relation theory and the role of the clinical nurse specialist. Part II: Application to advanced nursing roles in a professional practice model

CONCEPTS AND ASSUMPTIONS of self-in-relation theory of women's development, as proposed by feminist scholars at the Stone Center in Wellesley, Massachusetts, are applied in this article. This theory was used as a framework to guide staff development and mentorship roles of advanced practice nurses. How the theory served to direct these roles and assisted in development of a professional practice model is discussed. Exemplars from the authors' practices and professional practice outcomes after 2 years of theory implementation are presented.     

Decoupling: theory and practice. II. State of the art: in vivo applications of decoupling

Current methods for broadband heteronuclear decoupling are reviewed from a historical perspective. The principal concern is that decoupling should be effective over a wide range of chemical shifts without undue radiofrequency heating of the sample, particularly when human patients are involved. Continuous-wave methods are the least efficient in this respect, followed by noise decoupling. Composite pulse schemes offer a more effective use of radiofrequency power, while adiabatic passage methods are the most efficient of all. Bi-level decoupling employs a low level of radiofrequency irradiation during the relaxation delay to maintain the nuclear Overhauser effect, with a higher level during signal acquisition in order to decouple over a wide frequency band. All decoupling sequences introduce cycling sidebands into the observed spectrum, and schemes are described to minimize the intensity of these artifacts. In part II, practical applications of decoupling methods are examined in the context of in vivo spectroscopy, where the improvements in sensitivity and resolution through broadband decoupling can be critical for solving clinical problems. Attention is focused on the regulatory limits on power deposition in these experiments. A tabulation of the existing work on decoupling in biological tissue is presented, mainly involving 31P and 13C spectroscopy in vivo or in vitro.     

Optimal control of an aluminum casting furnace: Part II. Fuel optimization

In this second of a two-article series, the simplified model of the aluminum casting furnace presented in Part I is used to solve a fuel-optimal control problem. Basically a Lagrange problem with equality and inequality constraints, it is formulated through variational calculus into a two-point boundary-value problem with known initial and final conditions and specified final time. It yields an optimal solution with a time-vary ing fuel flow rate that gives 10.9 pct fuel economy over the conventional nonoptimal constant fuel flow rate. This shows that variational calculus can be used to solve optimal control problems for the aluminum casting furnace and for other similar thermal systems commonly encountered in the metallurgical industry.     

Test burning: Part II.

A research program, sponsored by the Rip Van Winkle Foundation, concerned with mental health in rural areas was started in 1955. A few members of the Hudson Post of the American Legion opposed the organized "mental health movement." Local newspaper articles linked "mental health with 'world citizenship, one worldism, internationalism, communism, and socialism.'… Actually, the ruckus did not blow up until the period of data collection from the children was in its last week. Data from only three children were destroyed in compliance with the wishes of their parents." Details of the background and the problem are presented. From Psyc Abstracts 36:02:2AA37E. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Thermal stress fracture of refractory lining components: Part II. Safe heating and cooling rates

The solution for the maximum principal tensile stress of a two-dimensional constant heating rate thermoelastic model has been used to develop a resistance-to-fracture-initiation parameter useful for the design and selection of refractory components that accounts for thermal and mechanical properties, geometry, and temperature range, as well as distinguishes between the heating and cooling cases. The parameter, namely safe heating or cooling rate, is defined as the maximum rate at which a rectangular shape can be heated or cooled through a specified temperature range without causing fracture, which is taken to be governed by the maximum principal tensile stress fracture criterion. Computation of the parameter is easily accomplished using a graphical technique. Tabulated values are used to plot dimensionless relationships that give the combinations of variables that both satisfy the fracture criterion and produce a specified value of hot face temperature. Good agreement was found between model predictions of safe heating rate and experimental values reported in the literature.     

Family stress: Integrating theory and measurement.

Family stress theory and family stress measurement were critically reviewed. After R. Hill's (1949) original formulation, 4 factors in family stress were examined: the stressor, family resources, family perceptions, and stress outcomes. The research findings clearly indicate that change per se can no longer be viewed as the essence of family stress and that the focus should be on negative changes and, in particular, loss. Family resources, such as cohesiveness, flexibility, social support, and shared family values, were evaluated as key stress-resistance attributes. Resource conservation and utilization models were applied in explaining the origins of stress for families and how existing resources aid families during stressful circumstances. One stress model, termed the conservation of resources theory, was applied to the family stress context. The popular concept of resource fit was also challenged and revised. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Occupational blood exposures in dentistry: a decade in review

This review summarizes data from self-reported and observational studies describing the nature, frequency, and circumstances of occupational blood exposures among US dental workers between 1986 and 1995. These studies suggest that, among US dentists, percutaneous injuries have declined steadily over the 10-year period. Data also suggest that, in 1995, most dental workers (dentists, hygienists assistants, and oral surgeons) experienced approximately three injuries per year. Work practices (eg, using an instrument instead of fingers to retract tissue), safer instrumentation or design (eg, self-sheathing needles, changes in dental-unit design), and continued worker education may reduce occupational blood exposures in dentistry further.     

Occupational stress, locus of control and health among men in a prairie province.

Analyzed the health-related consequences of occupational stress in 854 Saskatchewan adult male employees. The moderator effects of locus of control on stress-outcome relationships were also examined, as were interoccupational differences in the perception of job stress. Ss were administered the James Internal–External Locus of Control Scale and the General Health Questionnaire. Results confirm expected occupational group differences in the perceptions of stress. Stress was related to job strains, general health, and alcohol consumption. Locus of control moderator effects were, for the most part, limited to interpersonal support-seeking behaviors. (French abstract) (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Assessment of posttraumatic stress disorder in World War II veterans.

Four posttraumatic stress disorder (PTSD) scales were compared in a community sample of 330 American former prisoners of war and combat veterans of World War II. The Mississippi Scale for Combat-Related PTSD (M-PTSD), the MMPI-2 Pk PTSD scale, and the Impact of Event Scale (IES) all demonstrated moderate relationships with PTSD as defined by the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders-III-Revised (DSM-III-R). Comparative validities were similar to those observed in Vietnam veteran samples. Confirmatory factor analysis indicated that the 3 scales loaded significantly on 1 factor. The impact of Diagnostic and Statistical Manual of Mental Disorders (4th ed.) PTSD criteria changes was examined and found to be minimal. Implications for the use of the M-PTSD, Pk, and IES in combat-related PTSD assessment are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Occupational stress: Its causes and consequences for job performance.

Examined occupational stress and its relation with individual characteristics, job conditions, stressful events, affect, and job performance. Study 1, in which 104 nurses participated in group discussions and 96 nurses (mean age 36 yrs) completed a questionnaire, identified 45 stressful events (appended) for nurses. In Study 2, 171 nurses (mean age 34.6 yrs) completed another questionnaire and were rated by a supervisor and/or a coworker. Findings show that ratings of interpersonal aspects of job performance (i.e., sensitivity, warmth, consideration, tolerance) and cognitive/motivational aspects (i.e., concentration, composure, perseverance, adaptability) correlated significantly with self-reported perceptions of stressful events, subjective stress, depression, and hostility. Models developed through path analysis suggest that the frequency and subjective intensity of the 45 events identified in Study 1 caused feelings of stress, leading to depression and causing decrements in interpersonal and cognitive/motivational aspects of job performance. (43 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sedation in dentistry. Part 2: Management of the gagging patient

Erythromycin, an antibiotic commonly used topically in the treatment of acne, is unstable in solution. The stability is influenced by the pH and by the presence of water. The influence of the pH on the stability of erythromycin was investigated even with the use of dimethyl isosorbide as co-solvent instead of water. The addition of zinc was attempted to ameliorate erythromycin stability as suggested in the literature. To investigate these three factors and their interactions, an optimization technique was carried out consisting of a 2(3) factorial analysis and a rotative central composite design. The erythromycin solutions were analysed with an HPLC method. The pH and the concentration of dimethyl isosorbide had a significant influence on the stability of erythromycin but the addition of zinc was not a significant factor. Moreover, there was a significant interaction between the pH and dimethyl isosorbide.