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)     

Mechanical behavior of Al−Li−SiC composites: Part I. Microstructure and tensile deformation

The microstructure and tensile properties of an 8090 Al−Li alloy reinforced with 15 vol pet SiC particles were investigated, together with those of the unreinforced alloy processed following the same route. Two different heat treatments (naturally aged at ambient temperature and artificially aged at elevated temperature to the peak strength) were chosen because they lead to very different behaviors. Special emphasis was given to the analysis of the differences and similarities in the microstructure and in the deformation and failure mechanisms between the composite and the unreinforced alloy. It was found that the dispersion of the SiC particles restrained the formation of elongated grains during extrusion and inhibited the precipitation of Al₃Li at ambient temperature. The deformation processes in the peak-aged materials were controlled by the S′ precipitates, which acted as barriers for dislocation motion and homogenized the slip. Homogeneous slip was also observed in the naturally aged composite, but not in the unreinforced alloy, where plastic deformation was concentrated in slip bands. The most notorious differences between the alloy and the composite were found in the fracture mechanisms. The naturally aged unreinforced alloy failed by transgranular shear, while the failure of the peak-aged alloy was induced by grain-boundary fracture. The fracture of the composite in both tempers was, however, precipitated by the progressive fracture of the SiC reinforcements during deformation, which led to the early failure at the onset of plastic instability.     

Dendritic Growth Morphologies in Al-Zn Alloys—Part I: X-ray Tomographic Microscopy

Upon solidification, most metallic alloys form dendritic structures that grow along directions corresponding to low index crystal axes, e.g., $\langle100\rangle$ directions in fcc aluminum. However, recent findings[1,2] have shown that an increase in the zinc content in Al-Zn alloys continuously changes the dendrite growth direction from $\langle100\rangle$ to $\langle110\rangle$ in {100} planes. At intermediate compositions, between 25 wt pct and 55 wt pct Zn, $\langle320\rangle$ dendrites and textured seaweeds were reported. The reason for this dendrite orientation transition is that this system exhibits a large solubility of zinc, a hexagonal metal, in the primary fcc aluminum phase, thus modifying its weak solid–liquid interfacial energy anisotropy. Owing to the complexity of the phenomenology, there is still no satisfactory theory that predicts all the observed microstructures. The current study is thus aimed at better understanding the formation of these structures. This is provided by the access to their 3D morphologies via synchrotron-based X-ray tomographic microscopy of quenched Bridgman solidified specimens in combination with the determination of the crystal orientation of the dendrites by electron-backscattered diffraction. Most interestingly, all alloys with intermediate compositions were shown to grow as seaweeds, constrained to grow mostly in a (001) symmetry plane, by an alternating growth direction mechanism. Thus, these structures are far from random and are considered less hierarchically ordered than common dendrites.     

Thermodynamic properties of molten sulfides: Part I. The system Ni−S

The equilibrium partial pressure of sulfur vapor over Ni?S melts has been determined by equilibrating the melts with H₂-H₂S gas mixtures at temperatures from 1100°C through 1600°C and for melt compositions ranging from nickel saturation up to about 27 wt pct sulfur. An optical interferometer was employed to monitor the system’s approach to equilibrium and to analyze the composition of the equilibrium gas phase. A mathematical model was employed to correlate these data with those of Nagamori and Ingraham² for temperatures from 800°C through 1100°C. The model was somewhat complicated but it described the Ni?S melts very well over unusually wide ranges of composition and temperature;e. g. σ (logP _S2 ^1/2 )=0.029.     

Dendritic solidification—I. Analysis of current theories and models

Recent advances in the theory of dendritic growth have been reviewed. These theories have attempted to obtain mathematically rigorous solutions to dendritic growth under steady state conditions, incorporating in them, with various degrees of success, essentially all the physical principles governing dendritic growth. Traditionally, these theories have relied on an “ad hoc” hypothesis requiring that the dendrite grow at the maximum possible growth rate. More recently, this hypothesis has been abandoned in favor of criteria which determine the conditions under which a dendrite tip will advance in a stable fashion into the liquid ahead of it. Simpler approaches to the problem are available, particularly for dendritic growth under an imposed thermal gradient. However, all the models relying on the simpler approach have been shown to be theoretically inconsistent and do not satisfactorily predict the limiting undercoolings at a dendrite tip for both very small and very large growth rates. The essential elements of any satisfactory quantitative model for dendritic growth have been summarized and a new model proposed. This new model will be shown to be theoretically consistent, at both the very low and very large growth rates, in the second part of this paper.     

Shock synthesis of silicides—I. experimentation and microstructural evolution

Niobium and molybdenum silicides were synthesized by the passage of high-amplitude shock waves through elemental powder mixtures. These shock waves were generated by planar parallel impact of explosively-accelerated flyer plates on momentum-trapped capsules containing the powders. Recovery of the specimens reveaved unreacted, partially-reacted, and fully-reacted regions, in accord with shock energy levels experienced by the powder. Electron microscopy was employed to characterize the partially-and fully-reacted regions for the MoSi and NbSi systems, and revealed only equilibrium phases. Selected-area and compositions of the reacted products. Diffusion couples between Nb and Si were crystal structure and compositions of the reacted products. Diffusion couples between Nb and Si were fabricated for the purpose of measuring static diffusion rates and determining the phases produced under non-shock condition. Comparison of these non-shock diffusion results with the shock synthesis results indicates that a new mechanism is responsible for the production of the NbSi₂ and MoSi₂ phases under shock compression. At the local level the reaction can be rationalized, for example, in the NbSi systems under shock compression, through the production of a liquid-phase reaction product (NbSi₂) at the Nb-particle/Si-liquid interface, the formation of spherical nodules (∼2 μm diameter) of this product through interfacial tension, and their subsequent solidification.     

Nonissues, real issues, and bias: Comments on C. Brooks Brenneis’s commentary.

The subject of memories of childhood abuse is complex, and there is much that is not yet known. The field does not need work that is replete with errors, missing information, misleading and subjective comments, or the creation of issues that are nonissues. What is needed is a revised conception of the relationship between psychological science and professional practice that emphasizes the reciprocity of the two. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cold work hardening in stages IV and V of F.C.C. metals—I. Experiments and interpretation

The paper presents numerous measurements which confirm stages IV and V to be general ranges of cold work deformation. Analogous to stage II, stage IV exhibits a linear athermal hardening with constant strain rate sensitivity and activation enthalpy. In stage IV the dislocation cell size is constant, while the dislocation density growth rate is markedly reduced compared with stages II and III. Features of stage V are analogous to stage III, the increase of strain rate sensitivity (decrease of activation enthalpy) indicating the onset of thermally activated dislocation annihilation. In stage V, the mechanism is identified as dislocation climb from observing subgrain formation and saturation in density of deformation induced vacancies. Comparisons with recent investigations of stage IV and V at high temperatures suggest a common picture of low and high temperature deformation which only requires principles of storage and annihilation for both screw and edge dislocations.     

Thin film forced velocity cells and cellular dendrites—I. Experiments

A new, compreheensive set of experimental systematics for the alloys succinonitrile-salol (S-Sa), succinonitrile-acetone (S-A), and pivalic acid-ethanol(P-E) is summarized. The contribution deals synthetically with transients involving the Mullins and Serkerka instability together with Ostwald ripening, pattern selection mechanisms, cell root instabilities, steady state wavelength and amplitude systematics spanning near threshold cellular and dendritic forms, anisotropic effects, facetting and hysteresis and systematics of the cell to dendrite transition. The observations reveal that there are two main stable or nearly stable branches of non-planar cellular solutions, both significantly involving solid state diffusion and excluding single-valued local equilibrium spatial structures. The normal single-valued,non-local equilibrium branch which we designated asdynamical has a scale decreasing with increasing velocity. The other triple-valued, near-marginal branch which we designate asquasi-equilibrium has a scale increasing with increasing velocity.     

Electromagnetically Modified Filtration of Aluminum Melts—Part I: Electromagnetic Theory and 30 PPI Ceramic Foam Filter Experimental Results

In the present work, laboratory-scale continuous filtration tests of liquid A356 aluminum alloy have been performed. The tests were conducted using standard 30 PPI (pores per inch) ceramic foam filters combined with magnetic flux densities (~0.1 and 0.2 T), produced using two different induction coils operated at 50 Hz AC. A reference filtration test was also carried out under gravity conditions, i.e., without an applied magnetic field. The obtained results clearly prove that the magnetic field has a significant affect on the distribution of SiC particles. The influence of the electromagnetic Lorentz forces and induced bulk metal flow on the obtained filtration efficiencies and on the wetting behavior of the filter media by liquid aluminum is discussed. The magnitudes of the Lorentz forces produced by the induction coils are quantified based on analytical and COMSOL 4.2^® finite element modeling.     

In-Situ Synchrotron Diffraction Studies on Transformation Strain Development in a High Strength Quenched and Tempered Structural Steel—Part I. Bainitic Transformation

In-situ phase transformation behavior of a high strength (830 MPa yield stress) quenched and tempered S690QL1 (Fe-0.16C-0.2Si-0.87Mn-0.33Cr-0.21Mo (wt pct)) structural steel during continuous cooling under different mechanical loading conditions has been studied. Time-temperature-load resolved 2D synchrotron diffraction patterns were recorded and used to calculate the phase fractions and lattice parameters of the phases during heating and cooling cycles under different loading conditions. In addition to the thermal expansion behavior, the effects of the applied stress on the elastic strains during the formation of bainite from austenite and the effect of carbon on the lattice parameter of bainitic ferrite were calculated. The results show that small tensile stresses applied at the transformation temperature do not change the kinetics of the phase transformation. The start temperature for the bainitic transformation decreases upon increasing the applied tensile stress. The elastic strains increase with increase in the applied tensile stress.     

Comparative Evaluation of Cast Aluminum Alloys for Automotive Cylinder Heads: Part I—Microstructure Evolution

Metallurgical and Materials Transactions A - The present study stages a comparative evaluation of microstructure and associated mechanical and thermal response for common cast aluminum alloys that...     

Was Walter Lippmann interested in stereotyping?: Public opinion and cognitive social psychology.

Walter Lippmann's public Opinion is much cited but little read. A review of references to Public Opinion by social psychologists over the last 20 years reveals the widespread beliefs that (1) the book focuses primarily on group stereotypes and prejudice, and (2) the concept of stereotyping originated with Lippmann. However, stereotypes, as currently conceived--as opposed to schemata more generally--do not play a central role in the book, and Lippmann did not introduce the concept (although he may have broadened it). In addition, throughout his long and distinguished career, he showed little interest in stereotyping, prejudice, and discrimination. Nonetheless, Public Opinion is a seminal work in the area of cognitive social psychology and (like other little read citation classics) still deserves to be read--including, ironically, by students of stereotyping and prejudice. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Institutional affiliations of contributors to scholarly and professional activities in counseling psychology: 1980–1983.

Used presentations at Division 17 programs of the American Psychological Association conventions, affiliations of authors of articles in the Journal of Counseling Psychology and The Counseling Psychologist, and Division 17 leaders to determine that the University of Maryland (College Park), Ohio State University, and the University of Iowa were the most highly active institutions in counseling psychology over the period 1980–1983. The size of the faculty and faculty rewards and pressures appear to be factors in determining ratings. Counseling psychologists in nonacademic settings are disadvantaged in making research contributions by these factors. Since most current counseling and clinical psychology graduate students are trained to be practitioners, it is suggested that research and professional leadership dimensions should be measured on their value to practitioners. It is further suggested that quality of supervision, knowledge of practitioner skills, and capacity to meet credentialing and/or licensing requirements should be included in evaluating graduate education in counseling psychology. (13 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Creep of metal-type organic compounds—I. Pure polycrystals and particle-hardened systems

The creep of polycrystalline camphene and succinonitrile was studied in uniaxial compression at temperatures of 273 and 293 K. Succinonitrile exhibited classic power-law creep under all conditions with a stress exponent of 5.4±0.1. Camphene showed power-law creep at higher stresses with an exponent of 4.7±0.1. However, at lower stresses, camphene exhibited diffusion creep. The minimum applied stress in each material was not sufficiently low to identify a threshold stress for creep. The creep of particle-hardened alloys was modelled using camphene and succinonitrile containing a dispersion of alumina particles of average size 0.4 μm. The volume percentage of alumina was varied from 0 to 6.6% for camphene-alumina and from 0 to 4.8% for succinonitrile-alumina. Creep measurements were made at 273 and 293 K. In all cases, creep was found to obey a power-law. The stress exponent increased by factors of up to 3 for camphene-alumina, and 2 for succinonitrile-alumina. The data could be described with the same stress exponent as that of the unalloyed systems by subtracting a back stress from the applied stress.     

Cyclic deformation of ferritic steel—I. Stress-strain response and structure evolution

The complete CSS-curve has been established for a low alloyed structural steel tested under plastic strain control. The curve which can be divided into three separate regimes has a plateau region between cyclic strain levels of 10⁻⁴ and 8·10⁻⁴. PSBs are formed on the specimen surface when the plastic strain range corresponds to the plateau regime. The PSBs are sites for crack nucleation. The substructure evolution as seen going along the CSS-curve and with accumulating numbers of cycles is documented in detail and includes: dislocation loops, veins, walls including the ladder-like walls usually associated with PSBs, labyrinths, cells, subgrains, banded cells and subgrains. At low and intermediate plastic strain ranges the surface grains contain a more fine-scaled substructure and develop features which appear in the interior at higher plastic strain ranges. At larger cyclic strain levels microbands and noncrystallographic deformation bands become dominating features. Heavily displaced and serrated grain boundaries are observed at intermediate and high plastic strains both in interior- and surface grains containing microbands, banded cells or banded subgrains.