Pull-out creep laboratory test for soft rocks

2021 ◽  
Vol 144 ◽  
pp. 104811
Author(s):  
N.S. Montero-Cubillo ◽  
R.A. Galindo ◽  
C. Olalla ◽  
M. Muñiz-Menéndez
Keyword(s):  
Laboratory Test ◽  
Soft Rocks ◽  
Pull Out

Experimental and Numerical Simulation Study on the Shear Stress for the Interfaces of Anchorage Type Structures

2010 ◽  
Vol 163-167 ◽  
pp. 1325-1328
Author(s):  
Zhi Xiang Zha ◽  
Wei Peng ◽  
Xi La Liu
Keyword(s):  
Numerical Simulation ◽  
Shear Stress ◽  
Laboratory Test ◽  
Plane Strain ◽  
Simulation Study ◽  
Stress Transfer ◽  
Plane Strain Condition ◽  
Strain Condition ◽  
Working Mechanism ◽  
Pull Out

A laboratory test of anchor pull-out model under plane-strain condition on the shear stress transfer for the interfaces of anchorage type structures was carried out in this paper. The results of test were verified by corresponding numerical simulation model. It was proved that the pull-out experimental model under plane-strain condition was an effective model used to research the working mechanism of anchorage structure.

The influence of heat treatment on the fiber/matrix interface in a SiC-reinforced glassceramic

1988 ◽  
Vol 46 ◽  
pp. 742-743
Author(s):  
E. Bischoff ◽  
O. Sbaizero
Keyword(s):  
Heat Treatment ◽  
Aluminum Silicate ◽  
Lithium Aluminum ◽  
Interfacial Region ◽  
Specimen Preparation ◽  
Crack Wake ◽  
Pull Out ◽  
Annealed Material ◽  
Ultrasonic Drilling ◽  
Fiber Matrix Interface

Fiber or whisker reinforced ceramics show improved toughness and strength. Bridging by intact fibers in the crack wake and fiber pull-out after failure contribute to the additional toughness. These processes are strongly influenced by the sliding and debonding resistance of the interfacial region. The present study examines the interface in a laminated 0/90 composite consisting of SiC (Nicalon) fibers in a lithium-aluminum-silicate (LAS) glass-ceramic matrix. The material shows systematic changes in sliding resistance upon heat treatment.As-processed samples were annealed in air at 800 °C for 2, 4, 8, 16 and 100 h, and for comparison, in helium at 800 °C for 4 h. TEM specimen preparation of as processed and annealed material was performed with special care by cutting along directions having the fibers normal and parallel to the section plane, ultrasonic drilling, dimpling to 100 pm and final ionthinning. The specimen were lightly coated with Carbon and examined in an analytical TEM operated at 200 kV.

Characterization of interfaces in CVD-coated nicalon fiber-reinforced SiC

1989 ◽  
Vol 47 ◽  
pp. 556-557
Author(s):  
K.L. More ◽  
R.A. Lowden
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Frictional Stress ◽  
Fiber Reinforced ◽  
Pull Out ◽  
Carbon Coated ◽  
Fiber Matrix

The mechanical properties of fiber-reinforced composites are directly related to the nature of the fiber-matrix bond. Fracture toughness is improved when debonding, crack deflection, and fiber pull-out occur which in turn depend on a weak interfacial bond. The interfacial characteristics of fiber-reinforced ceramics can be altered by applying thin coatings to the fibers prior to composite fabrication. In a previous study, Lowden and co-workers coated Nicalon fibers (Nippon Carbon Company) with silicon and carbon prior to chemical vapor infiltration with SiC and determined the influence of interfacial frictional stress on fracture phenomena. They found that the silicon-coated Nicalon fiber-reinforced SiC had low flexure strengths and brittle fracture whereas the composites containing carbon coated fibers exhibited improved strength and fracture toughness. In this study, coatings of boron or BN were applied to Nicalon fibers via chemical vapor deposition (CVD) and the fibers were subsequently incorporated in a SiC matrix. The fiber-matrix interfaces were characterized using transmission and scanning electron microscopy (TEM and SEM). Mechanical properties were determined and compared to those obtained for uncoated Nicalon fiber-reinforced SiC.

Advances in ultramicrotomy for physical sciences applications

1993 ◽  
Vol 51 ◽  
pp. 710-711
Author(s):  
G. McMahon ◽  
T. Malis
Keyword(s):  
Particle Surface ◽  
Zeolite Catalysts ◽  
Physical Sciences ◽  
Pull Out ◽  
Large Particles ◽  
Novel Applications ◽  
Metal Wires ◽  
Frequent Problem ◽  
Specific Orientation ◽  
Diamond Knife

As with all techniques which are relatively new and therefore underutilized, diamond knife sectioning in the physical sciences continues to see both developments of the technique and novel applications.Technique Developments Development of specific orientation/embedding procedures for small pieces of awkward shape is exemplified by the work of Bradley et al on large, rather fragile particles of nuclear waste glass. At the same time, the frequent problem of pullout with large particles can be reduced by roughening of the particle surface, and a proven methodology using a commercial coupling agent developed for glasses has been utilized with good results on large zeolite catalysts. The same principle (using acid etches) should work for ceramic fibres or metal wires which may only partially pull out but result in unacceptably thick sections. Researchers from the life sciences continue to develop aspects of embedding media which may be applicable to certain cases in the physical sciences.

Application of Traveltime Tomography to GPR Data: a Preliminary Laboratory Test.

2008 ◽  
Vol 1 (1) ◽  
pp. 83-93 ◽  
Author(s):  
M. B. GALATI ◽  
T. QUARTA ◽  
L. NUZZO ◽  
M. FEDI ◽  
B. GAROFALO
Keyword(s):  
Laboratory Test ◽  
Traveltime Tomography

Treatment of maternal hyperthyroidism with antithyroid agents and changes in thyrotrophin and thyroxine in the newborn

1981 ◽  
Vol 97 (2) ◽  
pp. 186-195 ◽  
Author(s):  
B.-A. Lamberg ◽  
E. Ikonen ◽  
K. Teramo ◽  
G. Wägar ◽  
K. Österlund ◽  
...  
Keyword(s):  
Laboratory Test ◽  
Cord Blood ◽  
Pregnant Women ◽  
Newborn Infants ◽  
Antithyroid Drug ◽  
Clinical Indication ◽  
Antithyroid Drugs ◽  
Serum Thyroxine ◽  
Antithyroid Agents ◽  
Serum Tsh

Abstract. Eleven pregnant women with concomitant hyperthyroidism were treated with antithyroid drugs. At monthly intervals serum thyroxine (T4) and triiodothyronine (T3) were measured with radioimmunoassay, the Sephadex uptake of radioactive triiodothyronine (T3U) determined and the free T4 and T3 indices calculated (FT4I, FT3I). TSH-binding inhibiting immunoglobulins (TBII) were determined by the radiomembrane assay. Serum TSH and T4 were measured at delivery from cord blood and/or from the newborn infants some days after birth. Serum TSH was significantly elevated in one infant. There was an inadequate post-partal rise in serum T4 concentration in this child and in another who showed only a marginal elevation of TSH. The mothers of these infants were given carbimazole in doses of 30 and 25 mg/day, respectively, at the time of delivery. No significant changes were seen in other infants, the daily doses being 20 mg of carbimazole or less. There was no clinical indication of hypo- or hyperthyroidism in any of the newborn. The TBII were positive in most patients and there was a trend of normalization during treatment. No relationship between the dose of antithyroid drug and the level of TBII could be seen. During treatment the dose was adjusted according to the FT3I values. This seems to be an adequate laboratory test for this purpose.

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