Closure laws of void in the core of cross wedge rolling shaft based on the floating-pressure method

2018 ◽  
Vol 98 (9-12) ◽  
pp. 2905-2916 ◽  
Author(s):  
Duanyang Tian ◽  
Xuedao Shu ◽  
Ying Zhu ◽  
Chang Xu ◽  
Sutao Han ◽  
...  
Keyword(s):  
Cross Wedge Rolling ◽  
Pressure Method ◽  
The Core ◽  
Closure Laws

Mesoamerican Polyhedral Cores and Prismatic Blades

1968 ◽  
Vol 33 (4) ◽  
pp. 446-478 ◽  
Author(s):  
Don E. Crabtree
Keyword(s):  
High Speed ◽  
Large Series ◽  
High Speed Photography ◽  
High Quality ◽  
Pressure Method ◽  
The Core ◽  
Quality Material ◽  
Muscular Coordination

AbstractThis paper deals with the results of the author"s attempts to replicate the obsidian polyhedral cores and prismatic blades of Mesoamerica. Blades have been produced by the direct percussion, indirect percussion, and pressure methods. The pressure method using a chest crutch and a clamp produces cores and blades which are true replicas of aboriginal specimens. The importance of preforming the core and of platform preparation is stressed, and it is pointed out that, usually, actual removal of the blade offers few problems. However, to produce exhausted cores which show the perfection of aboriginal specimens and a large series of nearly identical blades requires good muscular coordination, high quality material, the establishment of patterns or rhythms of motor habits, and the absence of distractions. The author also discusses the difficulties of recovering from mistakes in manufacture.High-speed photography of prismatic blade removal, at 5,000 frames per second, has helped illustrate the behavior of the material and of the stoneworker. These photographs also indicate that under the present experimental and photographic conditions the author (Crabtree) is able to remove a prismatic blade from a core in about 1,250th of a second.

Effect of Non-Uniform Temperature Field on Piece Rolled by Three-Roll Cross Wedge Rolling

2009 ◽  
Vol 16-19 ◽  
pp. 456-461 ◽  
Author(s):  
Ping Qiu ◽  
Hong Xiao ◽  
Ming Li
Keyword(s):  
Temperature Field ◽  
Finite Element Models ◽  
Optimal Temperature ◽  
Uniform Temperature ◽  
Cross Wedge Rolling ◽  
Practical Applications ◽  
Pressure Method ◽  
Cooling Conditions ◽  
Temperature Filed ◽  
Uniform Temperature Field

Defects of pieces rolled by cross wedge rolling (CWR) have great effect on its practical applications. With reference to the center-pressure method used often in the forging, the effects of non-uniform temperature field on defects were studied by using the three-roll CWR tests under different cooling conditions and the coupled thermo-mechanical finite element models. The porous can be reduced or even eliminated when the billets were rolled with a controlled non-uniform temperature filed. The optimal temperature gradient was determined by FEM, which can be used in practical applications.

Formation-Damage Evaluation From Nonlinear Skin Growth During Coreflooding

2011 ◽  
Vol 14 (02) ◽  
pp. 193-203 ◽  
Author(s):  
P.. Bedrikovetsky ◽  
A.S.L.. S.L. Vaz ◽  
C.. Furtado ◽  
A.L.S.. L.S. de Souza
Keyword(s):  
Particle Concentration ◽  
Filtration Coefficient ◽  
Complex Case ◽  
Formation Damage ◽  
Pressure Measurements ◽  
Pressure Method ◽  
The Core ◽  
Damage Coefficient ◽  
Point Pressure ◽  
Well Injectivity

Summary Injectivity decline of oilfield injection wells is a widespread phenomenon during seawater/produced-water injection. The decline may result in significant cost increase of the waterflooding project. Reliable modeling-based prediction of injectivity-index decrease is important for waterflood design as well as for the planning of preventive injected-water treatment. One of the reasons for well injectivity decline is permeability decrease caused by rock plugging by solid/liquid particles suspended in the injected water. The mathematical model for deep-bed filtration contains two empirical functions: the filtration coefficient and the formation-damage coefficient. These empirical coefficients must be determined from laboratory coreflood tests by forcing water with particles to flow through the core samples. A routine laboratory method determines the filtration coefficient from expensive and difficult particle-concentration measurements at the core effluent; then, the formation-damage coefficient is determined from inexpensive and simple pressure-drop measurements. An alternative three-point-pressure method uses pressure data at an intermediate point of the core, supplementing pressure measurements at the core inlet and outlet. The method provides unique and stable values for constant-filtration and formation-damage coefficients. In the current work, we consider a more complex case in which both coefficients are linear functions of retained-particle concentration. In this case, the model is fully determined by four constants. The three-point-pressure method furnishes unique values for the four model parameters. A new semianalytical model for axisymmetric suspension filtration was developed to predict well-injectivity decline from the linear coreflood data with pressure measurements in three core points.

What face familiarity feelings say about the lateralization of specific entities within the core system

2019 ◽  
Vol 42 ◽  
Author(s):  
Guido Gainotti
Keyword(s):  
Temporal Lobe ◽  
Memory System ◽  
Core System ◽  
The Core ◽  
Memory Traces ◽  
Specific Memory ◽  
Target Article ◽  
Temporal Structures ◽  
The Right

Abstract The target article carefully describes the memory system, centered on the temporal lobe that builds specific memory traces. It does not, however, mention the laterality effects that exist within this system. This commentary briefly surveys evidence showing that clear asymmetries exist within the temporal lobe structures subserving the core system and that the right temporal structures mainly underpin face familiarity feelings.

A scanning electron microscopic study on dissolving process of cholesterol gallstones by chenodeoxycholic acid (CDCA)

1978 ◽  
Vol 36 (2) ◽  
pp. 522-523
Author(s):  
T. Kanetaka ◽  
M. Cho ◽  
S. Kawamura ◽  
T. Sado ◽  
K. Hara
Keyword(s):  
Electron Microscope ◽  
Chenodeoxycholic Acid ◽  
Outer Surface ◽  
Electron Microscopic ◽  
Cholesterol Gallstones ◽  
The Core ◽  
Scanning Electron Microscopic Study ◽  
Scanning Electron Microscopic ◽  
Acceleration Voltage ◽  
Scanning Electron

The authors have investigated the dissolution process of human cholesterol gallstones using a scanning electron microscope(SEM). This study was carried out by comparing control gallstones incubated in beagle bile with gallstones obtained from patients who were treated with chenodeoxycholic acid(CDCA).The cholesterol gallstones for this study were obtained from 14 patients. Three control patients were treated without CDCA and eleven patients were treated with CDCA 300-600 mg/day for periods ranging from four to twenty five months. It was confirmed through chemical analysis that these gallstones contained more than 80% cholesterol in both the outer surface and the core.The specimen were obtained from the outer surface and the core of the gallstones. Each specimen was attached to alminum sheet and coated with carbon to 100Å thickness. The SEM observation was made by Hitachi S-550 with 20 kV acceleration voltage and with 60-20, 000X magnification.

The Structure and Development of Microbodies in the Fat Body and other Tissues of an Insect (Calpodes Ethlius)

1970 ◽  
Vol 28 ◽  
pp. 148-149
Author(s):  
M. Locke ◽  
J. T. McMahon
Keyword(s):  
Electron Microscopy ◽  
Liquid Crystals ◽  
Fat Body ◽  
Competitive Inhibitor ◽  
Dense Core ◽  
Urate Oxidase ◽  
Blood Proteins ◽  
Free Base ◽  
The Core ◽  
The Matrix

The fat body of insects has always been compared functionally to the liver of vertebrates. Both synthesize and store glycogen and lipid and are concerned with the formation of blood proteins. The comparison becomes even more apt with the discovery of microbodies and the localization of urate oxidase and catalase in insect fat body.The microbodies are oval to spherical bodies about 1μ across with a depression and dense core on one side. The core is made of coiled tubules together with dense material close to the depressed membrane. The tubules may appear loose or densely packed but always intertwined like liquid crystals, never straight as in solid crystals (Fig. 1). When fat body is reacted with diaminobenzidine free base and H2O2 at pH 9.0 to determine the distribution of catalase, electron microscopy shows the enzyme in the matrix of the microbodies (Fig. 2). The reaction is abolished by 3-amino-1, 2, 4-triazole, a competitive inhibitor of catalase. The fat body is the only tissue which consistantly reacts positively for urate oxidase. The reaction product is sharply localized in granules of about the same size and distribution as the microbodies. The reaction is inhibited by 2, 6, 8-trichloropurine, a competitive inhibitor of urate oxidase.

Exsolution and inversion in pigeonite from the Whin Sill, Northern England

1978 ◽  
Vol 36 (1) ◽  
pp. 474-475
Author(s):  
P.P.K. Smith
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Homogeneous Nucleation ◽  
Silicate Mineral ◽  
Antiphase Boundaries ◽  
Two Phase ◽  
Primitive Form ◽  
The Core ◽  
Nucleation Mechanisms ◽  
And Inversion

Grains of pigeonite, a calcium-poor silicate mineral of the pyroxene group, from the Whin Sill dolerite have been ion-thinned and examined by TEM. The pigeonite is strongly zoned chemically from the composition Wo8En64FS28 in the core to Wo13En34FS53 at the rim. Two phase transformations have occurred during the cooling of this pigeonite:- exsolution of augite, a more calcic pyroxene, and inversion of the pigeonite from the high- temperature C face-centred form to the low-temperature primitive form, with the formation of antiphase boundaries (APB's). Different sequences of these exsolution and inversion reactions, together with different nucleation mechanisms of the augite, have created three distinct microstructures depending on the position in the grain.In the core of the grains small platelets of augite about 0.02μm thick have farmed parallel to the (001) plane (Fig. 1). These are thought to have exsolved by homogeneous nucleation. Subsequently the inversion of the pigeonite has led to the creation of APB's.

Intramitochondrial Viruses of Reptilian Cell Origin

1972 ◽  
Vol 30 ◽  
pp. 318-319
Author(s):  
Philip D. Lunger ◽  
H. Fred Clark
Keyword(s):  
Particle Production ◽  
Outer Zone ◽  
Density Variation ◽  
Core Region ◽  
Mitochondrial Membranes ◽  
Virus Particles ◽  
The Core ◽  
Vipera Russelli ◽  
Maturation Stages ◽  
Type Particle

In the course of fine structure studies of spontaneous “C-type” particle production in a viper (Vipera russelli) spleen cell line, designated VSW, virus particles were frequently observed within mitochondria. The latter were usually enlarged or swollen, compared to virus-free mitochondria, and displayed a considerable degree of cristae disorganization.Intramitochondrial viruses measure 90 to 100 mμ in diameter, and consist of a nucleoid or core region of varying density and measuring approximately 45 mμ in diameter. Nucleoid density variation is presumed to reflect varying degrees of condensation, and hence maturation stages. The core region is surrounded by a less-dense outer zone presumably representing viral capsid.Particles are usually situated in peripheral regions of the mitochondrion. In most instances they appear to be lodged between loosely apposed inner and outer mitochondrial membranes.

Bonafide Substructure in the Core of Ferritin

1985 ◽  
Vol 43 ◽  
pp. 322-323
Author(s):  
William H. Massover
Keyword(s):  
Phase Contrast ◽  
Central Cavity ◽  
Amplitude Image ◽  
Ultrastructural Studies ◽  
The Core ◽  
Hydrated Ferric Oxide ◽  
Imaging Artifact ◽  
Contrast Image ◽  
Protein Shell ◽  
Regular Patterns

Each molecule of ferritin (d = 130Å) contains a core of iron surrounded by a 24-subunit protein shell. The amount of iron stored is variable and is present within the central cavity (d = 80Å) as a hydrated ferric oxide equivalent to the mineral, ferrihydrite. Many early ultrastructural studies of ferritin detected regular patterns of a multiparticulate substructure in the iron-rich core [e.g., 3,4], Each small particle was termed a “micelle“; a theory became widely accepted that a core consisted of up to six micelles positioned at the vertices of an octahedron. Other workers recognized that the apparent micelles were smaller or even disappeared if images were recorded closer to exact focus [e.g., 5]. In 1969, Haydon clearly established that the observed substructure was really an imaging artifact; each apparent micelle was only a dot in the underfocused phase contrast image of the supporting film superimposed on the amplitude image of the strongly scattering metal.

Electron Microscopy of Bacteriophage T7 Internal Head Proteins

1975 ◽  
Vol 33 ◽  
pp. 638-639
Author(s):  
P. Serwer
Keyword(s):  
Electron Microscopy ◽  
Bacteriophage T7 ◽  
Specimen Preparation ◽  
Dna Molecule ◽  
The Core ◽  
Internal Core ◽  
Phage T7 ◽  
T7 Phage ◽  
Preparation Techniques ◽  
Internal Head

The genome of bacteriophage T7 is a duplex DNA molecule packaged in a space whose volume has been measured to be 2.2 x the volume of the B form of T7 DNA. To help determine the mechanism for packaging this DNA, the configuration of proteins inside the phage head has been investigated by electron microscopy. A core which is roughly cylindrical in outline has been observed inside the head of phage T7 using three different specimen preparation techniques.When T7 phage are treated with glutaraldehyde, DNA is ejected from the head often revealing an internal core (dark arrows in Fig. 1). When both the core and tail are present in a particle, the core appears to be coaxial with the tail. Core-tail complexes sometimes dislodge from their normal location and appear attached to the outside of a phage head (light arrow in Fig. 1).

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