Relative Plate Research Articles

양측균열인장(DE(T)) 평판의 J-적분 시험을 위한 소성 η계수

Detailed two-dimensional and three-dimensional finite element (FE) analyses of double-edge cracked tension (DE(T)) specimens are carried out to investigate the effect of the relative crack length and the thickness on experimental J testing schemes. Finite element analyses involve systematic variations of relevant parameters, such as the relative crack depth and plate width-to-thickness ratio. Furthermore, the strain hardening index of material is systematically varied, including perfectly plastic (non-hardening) cases. Based on FE results, a robust experimental J estimation scheme is proposed.

New visualizations of global tectonic plate motions and plate boundary interactions

Clear understanding of detailed lithospheric plate motions has been impeded by lack of a suitable means of graphical representation. A series of coloured global maps are presented that reveal more detail in the patterns of both absolute and relative global plate motions. The use of continuous colour to represent velocities overcomes the limitations of earlier maps that used isolated vectors at selected points to indicate plate velocities. Velocity magnitudes and directions for entire surfaces of plates were computed at a resolution of 0.5°, and are shown on two separate maps. Relative motions between plates were decomposed into their shear and normal components, and are plotted on separate maps. Continuous colour is again used to indicate both the directions and magnitudes of sinistral/dextral and convergent/divergent motions for all plate boundaries. A final map of normalized velocity magnitudes for all plates reveals a global, fast ‘belt’ of plate motion that parallels a great circle aligned with the fastest portion of the Pacific Plate and orthogonal to the East Pacific Rise.

Anatomical studies of the urethral plate: why preservation of the urethral plate is important in hypospadias repair.

To describe the detailed anatomy of the urethral plate in relation to its controversial role in hypospadias surgery. A newborn penis with proximal penile hypospadias and two fetal penises with distal shaft hypospadias were included in the study; 30 normal fetal penises served as the control. Specimens were embedded in paraffin and serially sectioned (6 microm) after formalin fixation. Every 10th section was stained with haematoxylin and eosin. Immunohistochemical staining for nerves (S100), smooth muscles (alpha-actin), blood vessels (factor VIII) and epithelium (cytokeratins 7, 14 and 18) were used on selected sections, with particular attention to the urethral plate. Masson's trichrome and Sirius Red stains were used to localize collagen. There were extensive blood vessels, glands and smooth muscle under the urethral plate in the hypospadias specimens. These relatively well organized tissues corresponded to an abnormally formed corpus spongiosum. The glands underneath the urethral plate and adjacent to the normal urethra showed positive staining for cytokeratins 7 and 18, respectively (markers of endodermal origin) but were negative for cytokeratin 14 (a marker of ectodermal origin). Penile skin and urethral plate epithelium stained positively for cytokeratin 14 but not for cytokeratin 7 and 18. The urethral plate has a rich nerve supply, as determined by S100 staining. Collagen intensity under the urethral plate was no different from that in normal areas. Tunica albuginea stained intensely for type I and III collagen. These results show that the urethral plate is well vascularized, has a rich nerve supply and an extensive muscular and connective tissue backing. These features may explain the lower complication rate with onlay flaps than with tube flaps. Therefore, from these anatomical findings, we continue to advocate preservation of the urethral plate and the onlay island flap for hypospadias reconstruction.

Colonisation and persistence of patches of the crustose brown alga Pseudolithoderma sp.

Encrusting algae are one of the major occupiers of space on hard marine substrata and are thought to influence the patterns of distribution and abundance of other organisms in intertidal areas of rocky seashores. However, little is known about their ecology and the mechanisms which may affect their distribution and abundance in space and time. Pseudolithoderma sp., a brown encrusting alga common on intertidal rocky shores in northeastern New Zealand, occurs in discrete patches on sheets of the honeycomb barnacle Chamaesipho columna. Patches of the alga change their size and shape over a wide range of spatial and temporal scales. To identify potential mechanisms that may influence the life-history of this alga, patterns of colonisation and persistence of patches of Pseudolithoderma were monitored for 1 year by measuring the colonisation of spores of Pseudolithoderma on settlement plates in relation to existing patches of the alga, and measuring the amount of lateral expansion and contraction of established patches. Colonisation of Pseudolithoderma occurred at a variable rate throughout the year, but was consistently greater on plates placed on patches of Pseudolithoderma than those placed 1 m away from patches and was rare on plates placed 10 m away from established patches. Established patches of Pseudolithoderma had a much faster rate of lateral expansion (m 2 per year) than those previously measured for other species of crustose algae, and declined in area unpredictably. The rapidity and lack of seasonality in the changes of the patches is hypothesised to be due to a variable age structure of the patches of Pseudolithoderma, along with localised interactions with small grazers and the underlying barnacles on the rocky shore. This suggests that processes operating at a very localised scale may be equally or even more important in determining the demography of fleshy encrusting algae, such as Pseudolithoderma, than processes operating at larger scales.

Rooting hastened in onions by ascorbate and ascorbate free radical

Treatment of onion bulbs with ascorbate or its free radical hastened root emergence on the basal plate in relation to treatments with water or dehydroascorbate. This stimulation was accompanied by a significant increase of DNA synthesis per primordium. After a 24-h imbibition, ascorbate and ascorbate free radical also increased cell length. Ascorbate and ascorbate free radical apparently activated the onset of cell proliferation in root primordia, resulting in a shortening in G1-S transition. The possible action of the ascorbate system at the plasma membrane level is discussed.

Direct digitization of optical images using a photostimulable phosphor system.

The authors describe a method for directly digitizing optical images with a photostimulable phosphor (PSP) system. A PSP plate is initially charged with an exposure to a uniform x-ray field, and is then exposed to an optical image which discharges the plate in relation to the amount of incident light. Two applications were investigated: a contact-print technique for digitizing film radiographs, and a projection technique for digitizing transparent objects such as histology slides. Spatial uniformity was found to be adequate, and linearity of optical density response was excellent from 0.0-2.9 o.d. after look-up table correction. Spatial frequency response was degraded with the optical technique relative to the x-ray imaging properties of the plates, but was restorable by Fourier filtering. Image noise following spatial enhancement was satisfactory at intermediate to high optical densities using a high-resolution PSP plate, but was somewhat degraded at low densities.

Effect of the Stereoregularity of Poly(methyl methacrylate) on Interaction and Boundary Phase Structure between Poly(methyl methacrylate)/Poly(hydroxypropyl ether of bisphenol A) Blend and Polyamide Substrate

The interaction and boundary phase structure between poly(methyl methacrylate) (PMMA)/poly(hydroxypropyl ether of bisphenol A) (PHPE) blend (PMMA/PHPE blend) and polyamide substrate were studied by using the PMMA/PHPE blend composite reinforced with short Kevlar® fiber and the PMMA/PHPE film formed on nylon-6 plate in relation to the stereoregularity of PMMA. The interaction between the matrix and reinforcement is estimated to be weaker for the composite made with isotactic (i-) PMMA/PHPE blend compared with composites made with syndiotactic (s-) PMMA/PHPE and atactic (a-) PMMA/PHPE blends from the mechanical dispersion data. The boundary phase in contact with the substrate is comprised of a mixture of PMMA and PHPE for the i-PMMA/PHPE and s-PMMA/PHPE blends from the X-ray photoelectron spectra. The boundary phase of a-PMMA/PHPE blend is composed of almost PMMA alone as reported previously. These differences of the interaction and boundary phase structure can mainly be attributed to differences of such a molecular characteristic of PMMA as overall molecular conformation or degree of constraint on the rotation of molecular chains and the difference of the compatibility of PMMA with PHPE, depending on the streoregularity of PMMA.

Pressure losses in an isolated perforated plate and jets emerging from the perforated plate

Perforated plates find many practical applications in industry—as flow control devices in particular, to control the flow emerging from a wide-angle diffuser, with applications to electrostatic precipitator design. Thus, an objective of the present investigation is to add to the existing body of knowledge concerning the mechanisms of screen flow and the associated flow resistance. Experimental data describe the behaviour of the flow emerging from the perforated plates in relation to the measuring locations and geometry of the perforated plates. The main results of investigations are (1) static pressures, (2) velocity distributions and (3) flow angles at the rear side of the perforated plates where jets occur.

Analytic determination of limiting nominal pressure difference in a differential manometer and relative standard-orifice plate areas for gas and vapor flowmeters

Analytic determination of limiting nominal pressure difference in a differential manometer and relative standard-orifice plate areas for gas and vapor flowmeters

Tectonics, fluids and ore deposits: Mobilization and remobilization

The mobilization of metals leading to the formation of many known types of metallic resource involves the focussed flow of very large (km 3) fluid volumes. Different types of fluids, such as sea water, and metamorphic and meteoric fluids, with or without biomolecules, may be specific for certain metals or suites of metals. Where large fluid volumes are part of a geologic process there is potential for local metal enrichment. Examples of such processes, within the context of plate tectonics, include: convective flow of sea water at ocean ridges in relation to ophiolite CuZn mineralization and “black smokers”; subduction of metal-enriched sediments and the tectonic recycling of SnW mineralization; metamorphic dewatering of subducted oceanic crust in the context of Au deposits; metamorphic degassing around high-level granitic plutons; and metamorphic re-equilibration of the underthrust plate in relation to continental thrusting. In addition, during weathering processes, short-term leaching produces fertile soils, whereas long-term leaching can result in lateritic ores. The large-scale remobilization of ore deposits, or of mineralization where metal-enrichment is currently sub-economic, is improbable unless large fluid volumes are involved or the crust undergoes major tectonic re-arrangement. But it is perhaps possible that these situations are more common than we suppose, and that such multistage events are indicated by the long-term persistence of metallogenic provinces.

Low‐frequency transmission losses and effective flexural rigidity of cracked ice cover

Upward refraction in the artic causes substantial interactions of underwater acoustic waves with the ice cover. Although several research papers focused on the effects of ice cover roughness on transmission losses, apparently no studies have been reported on the effects of cracks in the ice cover on reducing the flexural rigidity of the ice plate in relation to leaky Lamb waves and energy exchange between the water and the ice. Coupling between the acoustic waves in the water and the elastic waves in the ice plate depends on the relative densities and phase velocities of the waves. Depending on the number, size, and spatial distribution of the cracks, the flexural wave velocity of a low‐frequency component may be higher or lower than the water compressional velocity. The steep sloped region of the flexural wave dispersion curve makes the low‐frequency transmission characteristics very sensitive to the presence of cracks which reduce the flexural rigidity. Laboratory ultrasonic models are used to provide physical insights into a potentially important low‐frequency transmission loss mechanism caused by the effective reduced flexural rigidity of the cracked ice cover. Thin plates with machined multiple shallow cracks are utilized. The crack spacing is about half a wavelength and the crack depth is less than 1/6 the plate thickness. [Work supported by DREP.]

Thecal Plate Tabulation and Variation in Peridinium balticum (Pyrrhophyta: Peridiniales)

Thecal Plate Tabulation and Variation in Peridinium balticum (Pyrrhophyta: Peridiniales)

Cretaceous Sinistral Strike Slip Along Nacimiento Fault in Coastal California

The San Andreas and Nacimiento faults of coastal California both separate granitic and metamorphic basement rocks of the Salinian block from partly coeval but contrasting Mesozoic terranes underlain by the Franciscan subduction complex. By analogy with Neogene dextral strike slip along the San Andreas fault, Cretaceous sinistral strike slip can be inferred along the Nacimiento fault in preference to hypotheses for tectonic erosion during subduction or for dextral strike slip of unspecified amount. Following restoration of known San Andreas and inferred proto-San Andreas dextral displacements, reversal of about 560 km (350 mi) of postulated sinistral slip on the Nacimiento fault brings four major Mesozoic lithotectonic belts of California and Baja California into simple al gnment as subparallel terranes related to Mesozoic subduction along the continental margin. Neogene deformation within the San Andreas transform system involved (a) elongation of the Salinian block by dextral slip along subsidiary faults that branch from the San Andreas fault, and (b) dextral rotation of crustal panels within the Transverse Ranges. Latest Cretaceous and/or earliest Paleogene dextral slip along a proto-San Andreas fault followed the San Andreas course in central California, but diverged westward in southern California. Nacimiento sinistral displacements occurred in mid-Cretaceous to early or medial Late Cretaceous time, after Cretaceous emplacement of plutons now within the Salinian block but prior to deposition of uppermost Cretaceous sedimentary sequences in central California. Available data on Mesozoic relative and absolute plate motions in the Mesoameric n region support the likelihood of Cretaceous sinistral strike slip subparallel to the California continental margin. Paleotectonic reconstruction of crustal blocks in California and Baja California to their inferred mid-Cretaceous relative positions shows the Salinian block inserted on a bias between the flanking Mojave and Peninsular Ranges blocks. Salinian granitic rocks thus formed an interior part of the Mesozoic batholith belt, and their initial strontium isotopic ratios are compatible with the gradients displayed by values from the adjoining blocks. The similar Mesozoic terranes that now lie east and west of the Salinian block were then adjacent to one another west of the Sierra Nevada block. Available paleomagnetic data neither support nor preclude the reconstruction, but additional work together with future detailed lithotectonic comparisons potentially can confirm or refute the hypothesis i represents. A correct interpretation of the Nacimiento fault is important for understanding the overall tectonic framework of petroliferous basins both onshore and offshore in coastal California.

The buckling of annular plates in relation to the deep-drawing process

Based on a two-dimensional buckling model of an elastic-plastic annular plate and the well-known energy method, the critical conditions for the elastic buckling and the plastic buckling of the flange of a circular blank during the deep-drawing process are obtained to improve upon previously given results[1, 4]. The influence of a blankholder upon buckling and on the number of waves generated can also be quantitatively predicted.

A comparison of the effect of open intramedullary nailing and compression-plate fixation on fracture-site blood flow and fracture union.

We compared the effects of compression-plating and open intramedullary nailing after reaming on the vascular supply to a standard fracture site, on the rate of fracture union, and on the biomechanical quality of bone after union, and on the biomechanical quality of bone after union in dogs. The proper location of a compression plate in relation to the periosteum also was investigated. Bone blood flow reached higher levels and remained elevated longer in fractures that were fixed with a rod than in those fixed with a plate. Rod-fixed fractures healed by periosteal callus, whereas plate-fixed fractures healed by endosteal callus. The fracture gained mechanical strength more slowly in the rod-fixed group than in the plate-fixed group. Subperiosteal or extraperiosteal placement of a plate revealed similar effects on bone-healing. Decisions to use intramedullary rods or compression plates for internal fixation of fractures should be based on knowledge of the biological effects of these procedures on blood flow at the fracture site and on the mechanical strength of the healing fracture. This study defines in quantitative terms the advantages and disadvantages of intramedullary rods compared with compression plates in the internal fixation of fractures.

Increased growth of human fibroblasts and arterial smooth muscle cells from diabetic patients related to diabetic serum factors and cell origin

Fibroblasts from 3 diabetic patients (DF) grew faster, resulting in higher cell counts in the stationary phase than fibroblasts from 3 age-matched healthy volunteers (NF). This difference was apparent when DF or NF were cultured in either diabetic (DS) or normal serum (NS). Diabetic serum increased growth of both DF and NF compared with normal serum. Total protein content per plate paralleled the increase of cell number per plate in relation to cell origin and serum type. DS increased growth and total protein per plate in the arterial smooth muscle cell line from a non-diabetic patient in a way similar to in DF and NF. It is concluded that increased growth of DF in vivo could result in an increased turnover of vascular cells with a shortened replicative lifespan, leading to an accumulation of basal lamina. This effect would be even further accentuated by exposure of DF to DS. Taken together with the increased protein synthesis the accelerated development of diabetic angiopathy could be the final consequence.

Remodelling after distal forearm fractures in children. II. The final orientation of the distal and proximal epiphyseal plates of the radius.

In 39 children the steric orientation of both the distal and the proximal epiphyseal plates of the radius was evaluated 4 months to 10 years after distal forearm fractures that had healed with residual angulation. A residual fracture angulation was found to induce a change in orientation of both the distal and proximal epiphyseal plates. The final result of the reorientation was a normalization of the inclination of the plates in relation to the long axis of the bone. The proximal epiphyseal plate attained practically a normal orientation. The distal epephyseal plate tended towards overcorrection. In two of the four cases with a primary angulation exceeding 20 degrees considerable normalization occurred, but a "normal" state was not reached. This indicates an upper limit for angulations permitting normalization of the orientation of the distal epiphyseal plate of the radius.

Remodelling after distal forearm fractures in children. I. The effect of residual angulation on the spatial orientation of the epiphyseal plates.

The effect of residual fracture angulation on the distal radial and ulnar epiphyseal plates was studied in children aged 1 to 15 years. Thirty-eight fractures located in the distal fifth of the forearm bones were observed for 1 to 25 months after the fractures had healed. The forearms were examined radiographically on two to five occasions and the inclinations of the epiphyseal plates in relation to the long axis of the proximal fragments were measured. The results showed that an abnormal inclination of the epiphyseal plate after healing of a distal forearm fracture induced an alteration of growth in the epiphyseal plate. The redistribution of growth tended to correct the abnormal inclination. The rate of correction followed an exponential course. The age of the child at the time of the fracture and the distance from the fracture to the epiphyseal plate did not influence the capacity for correction.

Quality Assessment of Weld Bond of Structurural Steel Plates in Relation to Brittle Fracture Initiation

Quality Assessment of Weld Bond of Structurural Steel Plates in Relation to Brittle Fracture Initiation

Absolute Motion of the Eurasian Plate: A Problem in Vector Geometry

Many workers have encountered difficulties with determination of the absolute motion of the Eurasian plate. The problem is accident of vector geometry caused by addition by two angular velocity vectors about 180° from each other and of similar length. Twp-proposed systems of absolute motion yield Eurasian plate motions at right angles to each other while the motions of most other plates vary little from system to system. The phenomenon is associated with slow-moving plates. To resolve this problem, much more precise relative and absolute motion idata will be needed. This kind of geometrical Accident could affect both relative and absolute plate reconstructions as they are extended back in time and might explain some of the apparent motion between hot spots suggested by other workers.