Evidence for a shear mechanism for the precipitation of γ-zirconium hydride in zirconium

In zirconium-hydrogen alloys, rapid cooling from an elevated temperature causes precipitation of the face-centred tetragonal (fct) phase, γZrH, in the form of needles, parallel to the close-packed <1120>zr directions (1). With low hydrogen concentrations, the hydride solvus is sufficiently low that zirconium atom diffusion cannot occur. For example, with 6 μg/g hydrogen, the solvus temperature is approximately 370 K (2), at which only the hydrogen diffuses readily. Shears are therefore necessary to produce the crystallographic transformation from hexagonal close-packed (hep) zirconium to fct hydride.The simplest mechanism for the transformation is the passage of Shockley partial dislocations having Burgers vectors (b) of the type 1/3<0110> on every second (0001)Zr plane. If the partial dislocations are in the form of loops with the same b, the crosssection of a hydride precipitate will be as shown in fig.1. A consequence of this type of transformation is that a cumulative shear, S, is produced that leads to a strain field in the surrounding zirconium matrix, as illustrated in fig.2a.

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Management of a Large Arteriovenous Fistula in the Face: A Case of Neurofibromatosis Type 1

Annals of Plastic Surgery ◽

10.1097/00000637-199709000-00015 ◽

1997 ◽

Vol 39 (3) ◽

pp. 308-313 ◽

Cited By ~ 9

Author(s):

Mustafa Yilmaz ◽

Emel Ada ◽

Haluk Vayvada ◽

Ali Barutçu

Keyword(s):

Arteriovenous Fistula ◽

Neurofibromatosis Type 1 ◽

Neurofibromatosis Type ◽

The Face

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Suppression of the face-centered-cubic-hexagonal-close-packed stacking fault in Co/Cu(111) ultrathin films by pulsed laser deposition

Applied Physics Letters ◽

10.1063/1.123049 ◽

1999 ◽

Vol 74 (3) ◽

pp. 425-427 ◽

Cited By ~ 20

Author(s):

M. Zheng ◽

J. Shen ◽

Ch. V. Mohan ◽

P. Ohresser ◽

J. Barthel ◽

...

Keyword(s):

Pulsed Laser Deposition ◽

Ultrathin Films ◽

Pulsed Laser ◽

Stacking Fault ◽

Laser Deposition ◽

Face Centered Cubic ◽

Hexagonal Close Packed ◽

The Face ◽

Face Centered

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Anatomic patterning in the expression of vestibulosympathetic reflexes

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.2000.279.1.r109 ◽

2000 ◽

Vol 279 (1) ◽

pp. R109-R117 ◽

Cited By ~ 31

Author(s):

I. A. Kerman ◽

B. J. Yates ◽

R. M. McAllen

Keyword(s):

Relative Proportion ◽

Vestibular Stimulation ◽

Nerve Fibers ◽

Spike Shape ◽

The Face ◽

Nerve Fascicle ◽

The Difference ◽

Vestibulosympathetic Reflexes

To investigate the possibility that expression of vestibulosympathetic reflexes (VSR) is related to a nerve's anatomic location rather than its target organ, we compared VSR recorded from the same type of postganglionic fiber [muscle vasoconstrictor (MVC)] located at three different rostrocaudal levels: hindlimb, forelimb, and face. Experiments were performed on chloralose-anesthetized cats, and vestibular afferents were stimulated electrically. Single MVC unit activity was extracted by spike shape analysis of few-fiber recordings, and unit discrimination was confirmed by autocorrelation. Poststimulus time histogram analysis revealed that about half of the neurons were initially inhibited by vestibular stimulation (type 1 response), whereas the other MVC fibers were initially strongly excited (type 2 response). MVC units with types 1 and 2 responses were present in the same nerve fascicle. Barosensitivity was equivalent in the two groups, but fibers showing type 1 responses fired significantly faster than those giving type 2 responses (0.29 ± 0.04 vs. 0.20 ± 0.02 Hz). Nerve fibers with type 1 responses were most common in the hindlimb (21 of 29 units) and least common in the face (2 of 11 units), the difference in relative proportion being significant ( P < 0.05, χ2 test). These results support the hypothesis that VSR are anatomically patterned.

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Association between the Anatomy of the Mandibular Canal and Facial Types: A Cone-Beam Computed Tomography Analysis

International Journal of Dentistry ◽

10.1155/2018/5481383 ◽

2018 ◽

Vol 2018 ◽

pp. 1-9 ◽

Cited By ~ 2

Author(s):

Rudyard dos Santos Oliveira ◽

Arlete Maria Gomes Oliveira ◽

José Luiz Cintra Junqueira ◽

Francine Kühl Panzarella

Keyword(s):

Anatomical Variations ◽

Mandibular Canal ◽

Root Tips ◽

Morphological Variations ◽

The Face ◽

Facial Types ◽

Type 3 ◽

Facial Type

We evaluated the anatomical variations of the mandibular canal associated with various facial types, age, sex, and side of the face studied. We analyzed 348 hemimandibles in subjects without a history of trauma, lesions in the lower arch, or orthognathic or repair surgery in the posterior mandible. Facial type was determined using the VERT index. The canal path was classified as Type 1 (a large, single structure passing very close to the root tips); Type 2 (a canal passing closest to the mandibular base); and Type 3 (a canal present in the posterior mandibular region, with a lower canal running through the mandibular branch, reaching the anterior region). Bifid canals (type 3) were classified into four categories according to the course and number of mandibular canals. The brachyfacial and mesofacial types presented a Type 1 canal in 95.5% (n=166) of subjects, in dolichofacial types, 68.2% (n=45) presented a Type 2 canal, while in the mesofacial type, a lower prevalence of the bifid mandibular canal was observed (13.0%, n=23) than in the other facial types. The bifid canal showed significant association with facial type only (p<0.05), but no significant association was observed with the anterior loop type (p>0.05). Facial type is significantly associated with the path and morphological variations of the mandibular canal, independently of the side of the face studied, age, and sex.

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First Encounters

Instant Neurological Diagnosis ◽

10.1093/med/9780199361953.003.0001 ◽

2016 ◽

pp. 1-22

Author(s):

Christopher H. Hawkes ◽

Kapil D. Sethi ◽

Thomas R. Swift

Keyword(s):

Fragile X ◽

Relapsing Polychondritis ◽

Neurofibromatosis Type ◽

Carney Complex ◽

Ehlers Danlos Syndrome ◽

Type Iv ◽

The Face ◽

Sturge Weber Syndrome ◽

The Voice

This chapter describes disorders that can be diagnosed as the patient enters the consulting room, and how the patient turns to close the door, walks toward the clinician and shakes the clinician’s hand. Much information is gleaned by inspecting the face, clothes, fingernails, and jewelry or listening to the voice and smelling the breath. The clinician works as a bedside Sherlock Holmes. Some of the symptoms addressed in this chapter include hypersalivation, Horner's syndrome, and macroglossia. Individual disorders described include idiopathic intracranial hypertension, neurofibromatosis type 1, Sturge-Weber syndrome, Waardenburg syndrome, Vogt Harada Koyanagi syndrome, Fabry’s disease, fragile X syndrome, relapsing polychondritis, myasthenia gravis, Ehlers Danlos Syndrome type IV, Carney complex, cocaine and meth addiction, and ankylosing spondylitis, among others.

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Oral-Facial-Digital Syndrome Type 1: Oral Findings in a 6-Year-Old Girl

Journal of Pediatric Genetics ◽

10.1055/s-0037-1618601 ◽

2018 ◽

Vol 07 (02) ◽

pp. 092-096

Author(s):

Zuhal Kırzıoglu ◽

Esra Oz

Keyword(s):

Oral Cavity ◽

X Chromosome ◽

Congenital Anomalies ◽

Syndrome Type ◽

Developmental Genetic ◽

The Face ◽

Genetic Anomaly

AbstractOral-facial-digital syndrome (OFDS) is a group of congenital anomalies with 13 different forms. OFDS type 1 (OFDS1) is a developmental genetic anomaly related to the X chromosome, that is often seen in girls, and affects the face, oral cavity, and extremities. In this study, we discuss the oral findings of a 6-year-old girl with OFDS1 and her situation after 2.5 years.

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The Cognitive Reality of Hierarchic Structure in Music

Music Perception An Interdisciplinary Journal ◽

10.2307/40285440 ◽

1989 ◽

Vol 6 (4) ◽

pp. 397-430 ◽

Cited By ~ 27

Author(s):

Mary Louise Serafine ◽

Noah Glassman ◽

Cornell Overbeeke

Keyword(s):

Similarity Judgment ◽

Judgment Task ◽

The Third ◽

Hierarchic Structure ◽

The Face ◽

Similarity Judgments ◽

Type 3 ◽

Better Than

Six experiments examined the cognitive reality of hierarchic structure in music. The first experiment showed that subjects were only moderately able to match a performed rendition of a hierarchic structure to the piece of music from which it was derived, with performance slightly better than chance. Metric accent emerged as a significant predictor of the tones perceived by subjects as structurally important. The second experiment showed that subjects' correct matchings were unlikely to be based on aesthetic preference, because performed renditions of (rule-governed) structures were not regarded as aesthetically preferable to nonstructures. The third experiment attempted to increase subjects' matching of structures and their original pieces through various task modifications, but these modifications did not increase performance over the success rate achieved in Experiment 1. Three additional experiments determined whether evidence of the distinction between structureand surface could be obtained in various similarity judgment tasks. Pairs of musical fragments were composed so that the members of each pair embodied (1) the same structure and same surface harmony, or (2) the same structure but different surface harmony, or (3) a different structure but same surface harmony. The rating task used in Experiments 4 and 5 showed that the members of Type-2 pairs of fragments were perceived to be just as similar as the members of Type-1 pairs, but Type-3 pairs were rated significantly lower in similarity. Thus, similarity judgments were based on underlying hierarchic structure, even in the face of radical harmony differences on the surface. This effect increased in strength with repeated hearing. The results support the cognitive reality of hierarchic structure, but are influenced by the type of perception used in a particular similarity judgment task and by the experience of repeated hearings.

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Hydrogen Adsorption of Ruthenium: Isosteres of Solubility of Adsorbed Hydrogen

MRS Proceedings ◽

10.1557/proc-513-99 ◽

1998 ◽

Vol 513 ◽

Author(s):

S. Yu. Zaginaichenko ◽

Z. A. Matysina ◽

D. V. Schur ◽

V. K. Pishuk

Keyword(s):

Phase Transition ◽

Free Energy ◽

Theoretical Investigation ◽

State Transition ◽

Hydrogen Adsorption ◽

Adsorbed Hydrogen ◽

Hydrogen Atoms ◽

Hexagonal Close Packed ◽

The Face ◽

Pressure Hydrogen

ABSTRACTThe theoretical investigation of solubility isosteres of adsorbed hydrogen has been performed for free face (0001) of crystals with hexagonal close-packed lattice A3 of Mg type. The face free energy has been calculated and its dependence on temperature, pressure, hydrogen concentration and character of hydrogen atoms distribution over surface interstitial sites of different type has been defined. The equations of thermodynamic equilibrium and solubility of adsorbed hydrogen have been defined. The plots of isosteres in the region of phase transition from isotropic to anisotropic state have been constructed and it has been established that in anisotropic state the order in distribution of hydrogen atoms over interstitial sites of different type must become apparent. Comparison of the theoretical isosteres with experimental for ruthenium has been carried out, the isotropic-anisotropic state transition can stipulate a stepwise and break-like change in isosteres.

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Deformation-induced γ → DI-α2 phase transformation occurring in the twin-intersection region of TiAl alloys

Journal of Materials Research ◽

10.1557/jmr.2007.0323 ◽

2007 ◽

Vol 22 (9) ◽

pp. 2416-2422 ◽

Cited By ~ 4

Author(s):

C.L. Chen ◽

W. Lu ◽

L.L. He ◽

H.Q. Ye

Keyword(s):

Phase Transformation ◽

Room Temperature ◽

Compositional Analysis ◽

Hexagonal Close Packed ◽

Partial Dislocations ◽

Close Packed Structure ◽

The Matrix ◽

Hexagonal Close Packed Structure ◽

Packed Structure ◽

Face Centered

Deformation-induced γ → DI-α2 phase transformation was verified to occur in the twin-intersection region of a Ti–45Al–8Nb (at.%) alloy compressed at room temperature. High-resolution image observations of the deformation-induced DI-α2 phase suggested that the orientation relationship between the DI-α2 and γ phases remained the typical one: (0001)DI−α2//{111}γ, [11¯20]DI−α2//〈101]γ. The conversion of stacking sequence from ordered face-centered tetragonal to ordered nonequilibrium hexagonal close-packed structure was accomplished by the movement of a/6〈11¯2] Shockley partial dislocations on every other {111}γ plane. Compositional analysis based on energy dispersive spectra revealed that the DI-α2 phase had the same composition as the matrix γ phase. No compositional diffusion occurred because the plastic deformation was carried out at room temperature. The strong stress concentration in the intersection region was the major force to induce the γ → DI-α2 phase transformation in the process of room-temperature compression.

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