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Many factors affect the health of rivers, broadly speaking, there are natural factors (topography, precipitation, climate, land surface, earthquakes, etc) and the human factor (utilization of rivers), in which human activity is the most important factor.
The human activities of utilization have changed the river's natural flow-sediment process and broken the original balance, resulting in a total amount of flow-sediment and their spatial and temporal distribution variation dramatically, thus affecting the health of a river.
Thus, reservoirs are not only the main influence factors of flow-sediment variation, but also the main factor contributing to river health changes.
It is a comprehensive evaluation method that can make factors quantifiable which are unclear in boundary and not easily quantifiable.
[5] Qizong Wu, in: Operational research and optimization methods, Mechanical industry press, Beijing (2003), In Chinese

During long-term storage, the stress produced by thermal cycle, storage, transportation, rapid boost during motor ignition and acceleration during flight will lead to the decline of structure and mechanical properties [4, 5].
The microstructure of polymer materials will directly affect the macroscopic mechanical properties, which will change more complex under strain.
In the process of processing, there is no need for user to intervene, and many complex inversion control parameters are not need to set in advance, thus reducing the error on the inversion results caused by human factors.
Sun, et al, Characterization of crosslinked rubber properties with low-field NMR, Chin.
Zhao, Influence of crosslink density on mechanical properties of natural rubber vulcanizates, J.

A previous study indicated that bonded joints can sustain higher loads and are lighter than mechanical interfaces [2].
Finite element model A three dimensional finite element model was created in PATRAN, using solid brick and wedge elements with orthotropic material properties for the composite open-end cylindrical laminated shell and the repair patch, with a stacking sequence of [45/-45/0/90]s, and isotropic properties for the adhesive, as in Fig.2 shown.
Fig. 7 The stresses of the bottom surface on the fourth layer Fig. 8 The stresses on the central of composite open-end cylindrical laminated shell As shown in figure 7 and figure 8, type-A, type-B and type-E are the main factors for the changed stresses of the fourth layer and the central of whole model.
Fig. 11 The stresses of the bottom surface on the eighth layer As shown in figure 11, type-C, type-D and type-F are the main factors for the changed stress of the eighth layer.
For the disbonded types, the type-C for the stress is the greatest factor than other disbonded types.

Wei c and A.Kiet Tieu d School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong NSW 2522, Australia a hx899@uow.edu.au, bjiang@uow.edu.au, cdwei@uow.edu.au, dktieu@uow.edu.au Keywords: Edge crack, thin strip, cold rolling, mechanics analysis, stress intensity factor Abstract.
It depends on macroscopic factors such as the roll geometry, rolling speed, reduction or pass schedule, lubrication or friction and mechanical properties, as well as on microscopic factors such as the microstructure and surface micro-topography [1].
There are some causes which affect propagation of edge crack, including material ductility, inhomogeneous deformation with an uneven edge profile, and transverse variations in stresses [4].
Better understanding of stress levels in the crack tip region can be obtained through stress intensity factors.
Vol. 48 (2006), p. 697 [9] Stress intensity factors and weight functions, edited by T.Fett and D.

Table 1 lists the properties of test specimens.
The mechanical properties of concrete and shear reinforcements were given in table 2 and table 3.
Table.2 Mechanical properties of concrete Specimen /MPa /MPa /MPa Specimen /MPa /MPa /MPa 1 40.6 27.15 3.585×104 6 34.1 22.81 3.328×104 2 24.0 16.05 2.647×104 7 37.1 24.81 3.484×104 3 24.0 16.05 2.647×104 8 37.1 24.81 3.484×104 4 34.1 22.81 3.328×104 9 24.0 16.05 2.647×104 5 27.4 18.33 2.798×104 Table.3 Mechanical properties of shear reinforcement reinforcement /MPa /MPa /MPa 10 388.54 559.23 1.88×105 Arrangement of Measuring Points.
It reflected that the mechanical properties of specimens were not good enough under the cyclic reversed loading.
The test results showed that moment was not the main factor affecting on the interface shear capacity, which is similar to the conclusion drawn by Mattock[3].

To study Steel reinforced concrete frame-reinforced concrete core wall (SRC frame-RC core wall) hybrid structure earthquake damage evolution and collapse mechanism, this paper holds the earthquake collapse mechanism, seismic collapse analysis and collapse control strategies as the mainline, establishes performance degradation and collapse criterion characterization based on structure dynamic characteristics, adopts incremental dynamic analysis (IDA) method to complete the prototype structure collapse-resistant test and quantitative assessment of seismic collapse analysis and determine the main factors that affect the structure collapse-resistant properties.
Under rare earthquake, plastic hinges mainly appear on the concrete core wall, the plastic hinge mechanism is unfavorable to seismic, once the core wall occurs large deformation and serious damage, the outer frame will cause instability or partial collapse of the entire structure. 2) Current research on the hybrid structure most contrary to a particular practical engineering structures, the existing research does not clearly reflect the collapse mechanism of such structures under earthquake, can not accurately assess the influence of various factors for collapse-resistant properties of such structure.
Apply IDA method based on nonlinear dynamic time history analysis, by introducing material dynamic damage constitutive, considering initial damage and damage evolution in the analysis process, to find out the SRC frame-RC core wall properties and response under different earthquake intensity.
Through statistical analysis of structural response-seismic strength parametric curves and combining with structural collapse criterion, to determine the critical earthquake standards. 5) Analysis of SRC frame- RC core wall hybrid structure collapse-resistant factors and collapse control.
[9] ATC-63 Quantification of building seismic performance factors[S].

In most of these materials processing by conventional methods is a major problem due to breakage and tool wear, uneconomical or even impossibility of processing, while the non-traditional manufacturing processes are applied without the usual restrictions on the mechanical properties and machinability of materials.
Substantial efforts have been made in understanding the influence of certain factors on abrasive water jet cutting.
Experimental investigation was conducted in order to study the influence of factors on cut quality in abrasive water jet cutting of aluminum alloy.
Design of experiment was conducted using input factors (machining parameters): material thickness (s) traverse rate (v) and abrasive flow rate (q).
Input factors and their levels are shown in Table 2.

During the operation of the machine, the rubber seals will be affected by factors such as force, temperature, and speed, which will cause the seal function to be lost gradually or instantaneously.
These factors are divided into two types, those that cause changes in the physical or chemical properties of the rubber belong to the first type; all kinds of factors related to the sealing substructure belong to the second type [8, 9].
These factors need to be taken into account when calculating the life, which involves the statistical properties of the material that belongs to the seal structure and actual testing [10,11].
Xu, Nano-mechanical properties of flame sprayed Ni-Cr-B-Si coatings, Materials Engineering, 46(2) (2018) 78-83
Chen, Study on mechanical properties of nano- reinforced, nitrile butadiene rubbe, Materials & Design. 31 (2010) 1023-1028

Nd:YAG laser welding between Ti and PET using pulse shaping CHEN Yu-jiao1, a, GUO Zhong-ning2,b, LIAN Hai-shan3,c 1,2,3School of Electromechanical Engineering, Guangdong University of Technology, Guangzhou 510006, China achenyulinayu@yahoo.com.cn, bznguo@gdut.edu.cn, chssmy1985@163.com Key words: laser joining, pulse shape, peak power, pulsed-width, welding quality Abstract: PET-Ti composites have already been preliminarily used in the medical area due to the benefit of moderate biocompatibility of PET and the excellent mechanical properties of Ti.
This article describes how pulse shape, peak power and pulse-width affect the welding quality.
Meanwhile, PET-Ti composites not only own the advantage of moderate biocompatibility of PET but also the excellent mechanical properties of Ti which have already been proved to preliminarily be used in the medical area[5,6].
Physical and mechanical properties for these materials are listed in Table1.
Risk factors of early and late complications in patients undergoing endovascular aneurysm repair [J].

The strong electrnegativity of the F atoms makes the Si-F bond of a high polarity, probably affecting the complete Si-O network, and favoring the reaction with the polar H2O molecules.
Evolution of mechanical hardness with precipitate formation: Evaluation of mechanical properties of inter-layer dielectric materials is important because these coatings undergo multiple thermal cycles and CMP processes in IC fabrication.
Additionally, mechanical properties of the low-k materials have been shown to depend on their k values.
To evaluate the mechanical properties, hardness of SiOF film was measured using nanoindentation technique.
The reduction in hardness with increasing fluorine concentration indicates degradation in mechanical properties of SiOF film due to increased film porosity by fluorine incorporation.