Search results

Anyway, in any tunnel, an important problem to be considered is the stability of surrounding country rocks which is related to different factors such as the rock property, structure of rocks, underground water, natural stress state, geological structure, digging method of the tunnel, supporting method and supporting time [1], etc.
Among these, underground water rich in folds is difficult to solve because its complex properties make it very trouble to know its movement and existence state.
We therefore know that topography is an important factor that affect the collection of underground water, but not the only one.
The effecs of underground water on rocks The underground water existing in rocks interacts with surrounding rocks, which on the one hand affects the physical, chemical and mechanical properties of rocks and on the other hand affects its own physical and chemical characteristics.
Underground water affects the moisture content of rocks, change the pore-water pressure in rocks and bring mechanical effects.

The v-K curves showed that the SCG susceptibility significantly affects the crack growth velocity of the different bioceramics.
The subcritical crack growth phenomenon is one of the paramount factors that determine the lifetime of ceramic dental restorations due to the humid oral environment.
Table 1 – Mechanical properties (KIc and Si – inert strength), SCG parameters (n, sf0, A and B) and stress intensity shape factor (Y) of tested dental ceramics.
This result also showed that the mechanical properties related to rapid fracture (KIc and inert strength) have limited effects on the SCG susceptibility, since Empress 2 presented relative high KIc and Si values (Table 1).
Therefore, for the development of new bioceramics for dental restorations, not only mechanical properties must be improved, but also they must have resistance against the strength degradation by SCG phenomenon.

Introduction The rheological properties of a polymer melt are very important in processing but are complicated by a number of factors such as flow rate, pressure and temperature.
All these factors can affect the rheological properties of polymer and rubber melts [1, 2].
The rheology of polymer melts is considered to be one of the most important factors in determining the properties of a polymer product especially for those which require good flow properties in polymer processing, fabrication and molding process.
The addition of carbon black in rubber matrix as a reinforcement is to modify the mechanical properties of the finished product and to control the viscoelastic behavior of the compound properties.
Flow Properties of Polymer Melts, 2nd Ed., London: George Godwin. 1981

This article studied the influence of the caustic soda flakes (CSF) – phosphogypsum (Ard) activator on the properties and microstructure of hydration product generated by carbide slag(CS)-flyash(FA) system which used in high-grade highways pavement.
However, the pozzolanic reaction can occurs with the Ca (OH)2 in carbide slag to generate a stable calcium silicate hydrate and other hydration products at room temperature.Under curing for a time,the hydration products can achieve good mechanical properties and water stability.
In this paper,by study of the composition and properties of carbide slag-flyash system,found that the overall performance of the product can continue to improved, having the potential of used in high grade highway base.
Design of tests The main factors affecting the 7-day strength are the ratio of carbide slag to fly ash, the amount of activator and the ratio of caustic soda flakes to phosphogypsum.
The experimental design about the main factors are shown in the Table 1.

Consequently, the effects of macro-segregation on the mechanical properties of cast Mg-alloys have not been characterized.
It is observed that the inverse macro-segregation of eutectic phase at the cast surfaces adversely affects the fatigue behavior: the fatigue resistance decreases substantially due to the presence of the surface segregation.
Therefore, there must be other microstructural factors responsible for this observed unexpected trend.
The process conditions for plate B specimens intended to decrease the porosity turn out to adversely affect the fatigue properties due to the formation of the macro-segregation on the cast surfaces.

In this study the structure and properties of surface layers obtained on cp-titanium workpieces by non-vacuum electron beam cladding of titanium carbide powder were investigated.
One of the promising techniques of titanium tribological properties improvement is the formation of hard coatings containing high-strength titanium carbide particles.
The high power beam injected to the atmosphere allows fabricating thick (up to 2 mm) high-quality coatings [11] without sacrificing properties of a base material.
Remy,  Mechanical, structural and tribological properties of titanium nitrided by a pulsed laser, Surf.
Li, Microstructure and Mechanical Properties of an in situ Synthesized TiB and TiC Reinforced Titanium Matrix Composite Coating, J.

From the Eq.1 and Eq.2, we can see that the shear stress can be controlled by the magnetic field strength, the properties of SFA and the shearing rate.
Besides the yield stress, field strength and rotating speed, the granularity of abrasives and the processing time are other important factors that may affect the removal rate.
The final surface roughness of work piece may be affected by many factors, but the granularity of abrasives and the type of abrasives, the relative velocity between the work surface of work piece and the abrasive particles in the SFA are very important threes.
Rotating speed of work piece is another important factor that may affect the final surface roughness.
To find out the optimum factors for various materials and figures may be a important task in further aim of our research.

It is found that an array with properties of high uniform density, low amorphous carbon content and highly aligned nano-tubes are better spinnable.
One of the limiting factors of sytems that uses piezoelectric patches is the size of the patches.
Discovery of carbon nanotubes and their fascinating properties have opened many probable applications for them.
The properties of sensor as crack detection show promise.
Schulz, The Effect of Substrate and Catalyst Properties on the Growth of Multi-Wall Carbon Nanotube Arrays, Materials Research Society, Fall Meeting, 2005.

In modern construction, the use of fine-grained concrete (FGC) is due to its special properties compared to traditional heavy concrete.
The third factor ‒ the content of the chemical additive does not directly affect the strength of the FGC, since its task is to regulate the W/C.
Factor х3 (plasticizer) also significantly affects the density; a coefficient b33 = –53.66 indicates the presence of an optimal area.
Dvorkin, Design prediction of properties and design of concrete compositions, М.: Infra Engineering, 2016
Dvorkin, Physico-mechanical properties of activated cement-ash binders, Concrete Technology, 2010, no. 11-12, pp. 35-37

In order to visually grade the timbers, the strength affecting features on each wooden member were surveyed according to the UNI standards 11035:2003 part 1 and 11119:2004.
Two dimensional stress waves contour maps in cross-section planes and, especially, in longitudinal planes permitted to have information on macroscopic strength affecting material features, such as big knots or knots clusters.
Since the beam in service has been refurbished (it showed good mechanical conditions), for laboratory testing we have been obliged to choose among the discarded beams, which have different geometrical and mechanical properties.
In detail, a preliminary throughout diagnostic campaign allows reducing the uncertainty pertaining material properties and conditions.
Determination of some physical and mechanical properties.