Cube System Research Articles

Ll 2 Al 3 Ti-based alloys with Al 2Ti precipitates—II. Deformation behavior of single crystals

The operating slip systems and flow behavior of single crystalline Al 66.8Ti 27.4Fe 5.8, a two phase Ll 2 + Al 2Ti material, was investigated as a function of temperatures using specimens with compressive axes near [001], [ 1 13], [ 1 12], [013] and [ 1 33]. The material shows a very limited compressive ductility, and fracture occurs by cleavage along planes of low indices, such as {011}, {001}, {013} and {111}. Slip occurs exclusively on the octahedral slip systems at low temperatures, and on both octahedral and cube systems at high temperatures. A transition in operating slip systems from octahedral slip to cube slip, similar to the one seen in Ni 3Al-type alloys, occurs as the temperature increases and as the orientation of the specimens change from near-[001] to near-[ 1 11]. The transition in slip system is attributed to the hardening effect of the Al 2Ti precipitates, rather than to the anisotropy of APB energy on cube and octahedral slip planes of the matrix. Because of the large hardening effect of the Al 2Ti, the two phase material is substantially stronger than single Ll 2 phase materials. The shape (but not the level) of the flow stress-temperature curve for the two phase material resembles that of the single phase Ll 2 material at low and intermediate temperatures. At high temperatures, however, the flow stress of the two phase material exhibits a sharp decrease, a feature which is not observed in the single phase Ll 2 materials and can be correlated with a continuous dissolution of the Al 2Ti precipitates at high temperatures.

Evaluation of a three-dimensional memory cube system

Silicon cubes consisting of 18-20 1-Mb DRAM chips have been fabricated. In the stacking process, the chips are joined by adhesive to form the cube, interconnected by chip metallization processes, and packaged on a ceramic pin grid array (PGA) substrate that is mounted onto a memory card for testing. Modification of an existing memory card permits the substrate with cube to be substituted in place of an array of 1-Mb DRAM memory modules that normally form the card array. Memory tube operation is verified by testing both original and cube memory cards on the same memory tester. Electrical signals for each of the cards are observed and compared. Extensive electrical modeling and simulation of the cube interconnect circuitry including the chip transfer metal, interchip bus lines, and PGA substrate were performed as part of the design and later verified. A high degree of interconnect and wiring redundancy was used to guarantee connection of all the chips in the cube to the applied control signals and data lines. >

The locking of 〈110〉 edge dislocations on {001} in L12ordered compounds: High-resolution electron-microscopy observations

Abstract In the 〈110〉{001} slip system in L12 ordered alloys, both screw and edge dislocations may become locked by dissociating into nonplanar structures. In this paper the structure of edge dislocations in the [110](001) primary cube system in Ni3Ga and Ni3(Al, Ti) single crystals has been observed with weak-beam and lattice-imaging microscopy. Near 600°C the edge superdislocations are locked in the double Lomer—Cottrell lock; near 700°C the edge dislocations are locked in nonplanar structures formed by climb dissociations. Both structures have been observed directly by high-resolution electron microscopy. The implications of the locking of the edge dislocations on the operation of 〈110〉{001} and 〈110〉{111} slip systems are discussed.

Analytical and simulation studies of a multiprocessor system for high-speed numerical computations

This paper describes the architecture of a multiprocessor system which we call the Broadcast Cube System (BCS) for solving important computation intensive problems such as systems of linear algebraic equations and Partial Differential Equations (PDEs), and highlights its features. Further, this paper presents an analytical performance study of the BCS, and it describes the main details of the design and implementation of the simulator for the BCS.

A multiprocessor architecture for solving nonlinear partial differential equations

This paper presents the architecture of a special-purpose multiprocessor system, which we call the Broadcast Cube System (BCS), for solving non-linear Partial Differential Equations (PDEs). The BCS has the following important features: (a) Being based on the conceptually simple bus interconnection scheme it is easily understood. The use of homogeneous Processing Elements (PEs) which can be realized as standard VLSI chips makes the hardware less costly. (b) The interconnection network is simple and regular. The network can easily be extended to vast number of PEs by adding buses with new PEs on them and by slightly increasing the number of PEs on existing buses. The interconnection pattern is highly redundant to support fault tolerance in the event of PE failures. (c) In terms of the switching delays, the delay a message undergoes between a pair of PEs connected to a common bus is zero. The maximum delay between any pair of PEs is one unit and thus a strong localization of communicating tasks is not needed to avoid long message delays even in networks of thousands of PEs. The effectiveness of the BCS has been demonstrated by both analytical and simulation methods using heat transfer and fluid flow simulation, which requires solution of non-linear PDEs, as a benchmark program.

Efficient algorithms for scan-converting 3D polygons

A three-dimensional scan-conversion algorithm, that scan-converts 3D planar polygons into their discrete voxel-map representation within a Cubic Frame Buffer ( CFB), is presented. The algorithm, which is a variation of a conventional 2D scan-line filling algorithm, is incremental and uses only simple operations like additions and tests inside the inner loops. The algorithm performs scan-conversion with computational complexity which is linear in the number of voxels written to the CFB. Another algorithm that scan-converts polygons clipped to the CFB boundaries with no added time complexity is also presented. Furthermore, an all-integer decision mechanism which makes the inner-most loop of the algorithm more efficient is discussed too. All the algorithms guarantee lack of 6-connected “tunnels” in the converted polygons. The algorithms have been implemented as part of the 3D geometry processor of the CUBE Architecture, which is a voxel-based system for 3D graphics. These algorithms allow the CUBE system to generate a discrete voxel representation of the essential 3D polygon primitive, enabling CUBE to also cater to applications generating synthetic images.

Friction and wear of Cu-Be and dispersion-hardened copper systems

Precipitation-hardened Cu-1.8wt.%Be alloys and copper dispersion hardened with Al 2O 3 or Cu 2O particles were tested on an LFW-1 sliding wear machine. A transfer layer of similar microstructure and hardness was observed on the surface of all sample materials. Microstructural, chemical and hardness measurements on debris particles indicate a close correlation between debris particles and transfer layers. The differences in friction, wear rate and debris particle morphology seem to be attributed to the different distribution and geometry of the transfer layer and to the hardness of the transfer material compared with the hardness of the sample material. These findings show that transfer material plays a significant role in both friction and wear for these systems.

Precipitation in a nickel-beryllium alloy

Precipitation was studied in a nickel 1.89 wt% beryllium alloy over the temperature range 400 to 750° C. Below 650° C, the precipitation sequence is analogous to that in the widely studied Cu-Be system: $$\alpha (supersaturated solid solution) \to \alpha + GP zones \to \alpha + \gamma '_{NiBe} \to \alpha + \gamma _{NiBe} $$ where the equilibrium γ NiBe phase is formed by a discontinuous reaction consuming the intermediate γ∼' NiBe. The morphology of the discontinuous γ NiBe was too irregular to assign a habit plane. Numerous orientation relations were observed between the α Ni and the discontinuous γ NiBe. The kinetics of the reaction were found to follow a linear growth with time. The activation energy of 58±3 kcal mol−1 is less than bulk diffusion of nickel but greater than grain boundary self diffusion. Above 650° C, the discontinuous reaction front is arrested before completion because the equilibrium γ NiBe forms by continuous coarsening of the γ′ NiBe phase. The continuous γ NiBe has a habit plane of {113}α. Three closely related orientations were observed at constant ageing parameters for the equilibrium continuous phase. Each has been separately proposed in the literature as a unique relation for the copper-beryllium system. For nickel-beryllium either all three are uniquely present or the accuracy of selected area diffraction technique is such that the small differences in orientation cannot be distinguished.

Precipitation hardening in Cu-Zn-Be alloys

Brasses containing 20 and 30 pct Zn and up to 1.15 pct Be have been examined to provide tensile test data on the age-hardening response of these ternary alloys. It was found that yield strengths of 1100 Mpa were attainable with cold working prior to aging at 300°C. The mode of precipitation, as determined by electron micros copy and electron diffraction, agrees substantially with recent work on the binary Cu-Be system. Precipitation commences as GP zones on the (001)α planes. The observed precipitate phase, after aging times of up to seven days at 400°C, is CuBe with an orientation relationship of the type (301)ppt ∥(113)α [010]ppt ∥[110]α.

Vectorial characteristics of ventricular extrasystoles stimulated during cardiac catheterization

Ventricular extrasystoles (VES) from different areas of the ventricular muscle mass were obtained by mechanical stimulation of inflow and outflow regions of the right ventricle (RV) and apical and basal portions of the left ventricle (LV) during cardiac catheterization. Cube system vectorcardiogram (VCG) patterns of VES from each location were analyzed to determine the specificity of vector orientation from each site. Transverse plane VCG distinguished between nonseptal LVES and RVES, while a combination of transverse and either sagittal or frontal planes permitted further localization of septal VES to inflow or outflow regions of the RV and apical and basal areas of the LV.

Microbial growth response to water sorption preparation

SummaryIntermediate moisture food systems were prepared by both an adsorption and desorption method to similar aws. Hysteresis occurred above an aw of 0.86. Four organisms, Candida cypolytica, Pseudomonas fragi, Staphylococcus aureus and Aspergillus niger, when inoculated in a pork system, showed more rapid growth in systems prepared by a desorption process than by an adsorption process at the same aw. In a solid chicken cube system, the same effect was found but the difference was less between the adsorption and the desorption systems. These results indicate that the method of addition of water to a food system as well as the aw is important in determining the response to growth.

Copper-Beryllium Microstructures

Recently, the late R. Shiromizu carried out studies to establish the limits of metastability in the Cu-Be system. Con-currently, we engaged in parallel research, but with a broader emphasis on the microstructures concomitant with quenching, aging and reversion. A complete report covering 0.16 to 2.1 wt.% Be will be published elsewhere; certain unique structures are presented below.Alloys of >0.8 wt.% Be quenched from the α (f.c.c.) region exhibit weak {110} tweed strain contrast. Direct lattice imaging did not detect discrete particles in this condition, whereas rather high densities of {100} G.P. Zone plates in regular stairstep array were revealed after aging at temperatures well below the G.P.Z. solvus.

Effect of VCG sensitivity to dipole content in detecting infarctional changes

The axial, the Frank, and the cube vectorcardiographic (VCG) lead systems have been examined for fidelity of reporting the dipolar component while excluding the non-dipolar component of surface potential records. Recordings were made from 142 sites on the chest of 28 normal young men, 19 men one month after an acute inferior infarction and 22 men one month after an acute anteroseptal infarction. The authors capitalized on the fact that the VCG is the dipole moment loop which has been altered by the particular recording system used in 3 distinct fashions: attenuation, dipolar distortion, and nondipolar inclusion. If an arbitrary value of 1 is assigned to the actual loop of dipole moment, the magnitude after attenuation by the clinical VCG falls into this range: axial.71, Frank.57, and cube .35. Dipolar distortion is greates in the cube system, causing the loop shape to move toward diagnosis in the case of inferior infarction, but away from it in anterior infarction. Non-dipolar addition is relatively greatest in the cube, but absolutely greater in the Frank and the axial system. Such inclusion alters the cube appearance toward diagnosis in inferior myocardial infarction, and away from it in anterior infarction. It significantly alters the appearance toward diagnosis in anterior infarction when recording with Frank system. This means of assay capitalizes on the extremely low incidence of false positives characteristic of the loop of dipole moment. It identifies for each instant in each VCG system the biases introduced by the respective system's dipolar distortion and nondipolar inclusion. With this approach it may be possible to specify those biases which increase the level of true positive diagnoses, and those which mainly increase false positivity and should perhaps be discarded.

Cross slip in phases having the L12 structure

Plastic deformation in phases having the Ll2 structure can occur on the {001} (110) system (cube slip) as well as on the {1ll} (101) system (octahedral slip). Primary and secondary slip may therefore occur with various combinations of the cube and octahedral slip systems. The stress fields around dislocation pile-ups on the primary slip system are calculated for these various combinations of slip system and it is shown that secondary slip can occur on the cube slip system over distances which are an appreciable fraction of the pile-up length, even when the Schmid factor for cube slip is zero, such as for (001) oriented crystals. Thus the change in the mechanism of work-hardening which was previously proposed5 to account for the anomalous temperature dependence of the flow stress of the γ’ phase based upon M3AI and which has the Ll2 structure, can also be applied to (001) oriented crystals of γ’, which also show the anomalous flow stress temperature dependence.3 The hypothesis predicts that the mobile dislocation behavior should be modified with change in temperature. Etch pit results are presented to show that freshly nucleated dislocation sources do respond differently under the same stress at 25° and at 400°. The observed behavior is consistent with the work-hardening model previously proposed.

Urea Biosynthesis in a Surviving Amphibian Liver Cube Preparation

Abstract The biosynthesis of urea in vitro was maintained at a constant rate for 48 hours in a surviving amphibian liver cube system. The maintenance of constant oxygen consumption and protein synthesis during this time indicated that the majority of cells remained viable. A direct correlation between the rate of fixation of 14CO2 and ammonia into urea and the levels of carbamyl phosphate synthetase in vitro was similar to observations made in the metamorphosing amphibian in vivo.

Reevaluation of a cube system: The kimura lead system

The relationships among the Kimura 1 , Grishman 2 , Frank 3 and McFee 4 lead systems of vectorcardiography were analyzed concerning 43 normal subjects, 34 patients with left ventricular hypertrophy (LVH) and 15 patients with anterior myocardial infarction. The terminal QRS vectors of LVH in the frontal plane were markedly displaced superiorly in the Kimura lead system as compared with the others. The mean values of instantaneous vectors of anterior myocardial infarction revealed more prominent shift in the Kimura lead system than those of the others. The direction of inscriptions of the QRS sÊ loop of LVH in the Kimura system showed “counterclockwise” in the frontal plane. This characteristic might be more useful in making a diagnosis of LVH than the other lead systems, especially better than corrected orthogonal systems.

The performance of VCG leads in homogeneous and heterogenous torsos

Three electrical, conductive models of the torso's frontal plane were constructed: homogeneous, model with lungs, model with lungs and heart's blood. Seven dipoles were energized in each of the 3 models, yielding 21 sets of imagespace data for evaluating six VCG systems: Tetrahedron, Cube, Frank RLF, Frank orthogonal, McFee, Parallel grid. In the homogenous model, Tetrahedron, Cube, and Frank's RLF system performed poorly, the leads demonstrating large variations in vectorial angle (range 40°) and magnitude (range 50%) as the dipole changed location. In contrast, the orthogonal systems of Frank, of McFee and Parallel Grid demonstrated very good performance. Lead vectors deviated less than 7° from ideal direction. The strength of Y -axis leads did not vary by more than 8%. The only weak aspect was a variation in strength of X -axis leads. The addition of lungs caused considerable deterioration of all VCG systems, and their respective performances were worse with the further addition of heart's blood. The three corrected systems, Frank, McFee, Parallel Grid, which performed so well in the homogeneous torso, now demonstrated considerable variation in angle (range 35°) and magnitude with change in the dipole's location. Little was gained from the multiplicity of electrodes in the parallel grid system. The data shows that a VCG system based upon data from homogenous torsos will deteriorate when applied to a heterogenous torso with lungs and blood. Excellent performance of a VCG system on a homogenous model provides no assurance of satisfactory performance on a human torso.

Vectorcardiogram in dextrocardia, dextroversion and dextroposition

The vectorcardiograms were analyzed in a group of 17 patients with the heart displaced to the right. There were 14 studies of patients with mirror-image dextrocardia, 4 with dextroversion and 2 with rotated dextroposition, making a total of 20 vectorcardiographic studies for consideration. The Grishman cube system of electrode placement was employed with the cube formed in the usual manner to the right and inverted to the left. In mirror-image dextrocardia without cardiopathy the usual cube vectorcardiogram showed: (1) P and T loops to the right with clockwise rotation of the P in the VCG F and VCG H; (2) initial forces of the QRS directed to the left and anteriorly; (3) major QRS H forces directed to the right and anteriorly; (4) clockwise rotation of the QRS H; (5) terminal QRS H forces lying posteriorly in the midline or slightly to the left; and (6) considerable exaggeration of the QRS H forces along the anteroposterior axis. In mirror-image dextrocardia with left ventricular hypertrophy the above pattern of the usual vectorcardiogram cube was altered by: (1) displacement of the centripetal limb of the QRS toward the right; (2) increased QRS forces directed anteriorly; and (3) clockwise rotation of the QRS F. Biventricular hypertrophy produced a usual cube QRS with: (1) important areas lying anteriorly and also posteriorly; and (2) final forces that were, with greater relative right ventricular hypertrophy and right bundle branch block, augmented, slurred, directed to the left posteriorly and superiorly, to the extent that the rotation of the QRS sometimes became counterclockwise. Right ventricular hypertrophy in mirrorimage dextrocardia produced: (1) counterclockwise rotation of the QRS H with major forces directed anteriorly and to the left; and (2) 0.01 sec. vector to the left and anteriorly as in the previous groups. In mirror-image dextrocardia with corrected transposition of the great vessels the usual cube showed: (1) initial QRS forces directed to the right, whereas in all the groups mentioned they were to the left; and (2) counterclockwise rotation of QRS H in 2 cases, and clockwise in 1. In mirror-image dextrocardia the inverted cube produced vectorcardiographic configurations that were at once more familiar and compatible with the diagnoses of the patient. On the basis of these results as well as theoretic considerations, the inverted cube is considered to be a more accurate technic than the usual cube in mirror-image dextrocardia. Thus, the inverted cube has been adopted for routine use in evaluating cases of probable or proved mirror-image dextrocardia in this laboratory. In dextroversion without associated cardiopathy and in rotated dextroposition the usual cube produced: (1) P loops directed to the left and anteriorly, or directly anteriorly, with counterclockwise rotation in VCG F; (2) initial QRS forces directed to the right; (3) counterclockwise rotation of the QRS H; and (4) a large QRS area lying anteriorly, to the left and inferiorly. In dextroversion with associated left ventricular hypertrophy the usual cube showed, in addition to these characteristics, a late loop of clockwise rotation in the QRS H directed to the left and posteriorly. Corrected transposition in dextroversion produced a usual cube vectorcardiogram with: (1) P loops directed to the left and anteriorly, or directly anteriorly, with counterclockwise rotation in VCG F and VCG H; (2) 0.01 sec. QRS vector directed anteriorly and slightly to the right; (3) clockwise rotation of QRS H and (4) T loops directed to the right and anteriorly. The inverted cube vectorcardiogram in rotated dextroposition and in dextroversion without cardiopathy or with associated left ventricular hypertrophy has characteristics in common with the inverted cube curves of a normal heart. This suggests that the usual cube is a more valid technic when the heart is in the right side of the chest in situs solitus with a normal atrioventricular relation. In dextroversion with associated corrected transposition, the vectorcardiographic configurations produced by the inverted cube were rather at variance, whereas those of the usual cube were more similar and useful. However, only 2 cases of this condition were available for consideration. The vectorcardiogram would appear to be a useful tool in the investigation of malposition of the heart. Greater experience will undoubtedly clarify some of the problems that now remain.

Vectorcardiogram in Normal School Children Comparison of the Frank Lead System and the Cube System of Grishman

Vectorcardiogram in Normal School Children Comparison of the Frank Lead System and the Cube System of Grishman

Vectorcardiographic studies in infants and children: I. Comparative orthogonal lead studies in the neonatal period

Planar vectorcardiographic QRS loops of 33 normal, term infants were recorded by the Grishman cube, Frank and McFee-Parungao axial lead-placement systems on the first through the third days of life. No changes occurred in direction of loop inscription or in magnitude of the mean and maximal planar and spatial QRS vectors that might reflect changing ventricular loading patterns during the period of transition from the fetal to adult circulation. In this group of infants the orthogonal systems performed quite similarly; the major differences observed among recordings were in the magnitudes of the recorded X, Y and Z deflections, which were greatest for the axial system and smallest for the Frank system. On successive days of life, mean and maximal QRS vectors were of a similar, but not identical, order of magnitude and orientation for a given lead system, but in individual instances wide deviations were observed. In general, in most infants QRS vector directions were right, inferior and anterior, thus reflecting the expected electrical and anatomic preponderance of the right ventricle at this age. The cube system, an unweighted lead system based on geometric placement of skin electrodes, performed in approximation to the orthogonal systems. It was, in general, a technically unsatisfactory system, even though electrode placement seemed to offer the advantage of fewer electrodes. Tracings in general were small, with considerable noise level produced by body tremor; this factor, together with the small signal, produced a small signal to noise ratio. These data will be expanded to encompass measurements from a much larger series of infants, with more detailed, extensive analysis made possible through the use of digital computer technics.