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Mihai Viteazul nr. 24, Timisoara, Romania abogdan.radu@upt.ro, bviorel.ungureanu@upt.ro, cioan.both@upt.ro, dmircea.burca@upt.ro, ebenzarstefan@yahoo.com, fdan.dubina@upt.ro Keywords: resistance spot welding technology, galvanized steels, microstructures, optic microscopy, mechanical elongation tests.
Resistance spot welding technologies were developed and tested, together with mechanical testing of the welded joints, which were performed in our laboratories.
Introduction In the last years, structures designers focused their work on developing new techniques, which allows an economy of materials and working time, which will also guarantee a safe exploitation, the structure respecting all standard prescriptions and safety factors.
Because one of the very important properties for the life expectancy, of the metallic structures which are placed in atmospheric environment, is the resistance to corrosion and this property is highly dependent to the thickness of the Zn protecting layer, our experimental program also measured this parameter.
The curve force-displacement (fig. 3.b) for the samples welded with the welding parameters presented in table 2, revealed good ductility (toughness of the material in the nugget and also in the Heat Affected Zone – ZIT, with no brittle behavior) and very good capacity to support loads.

It is one of the main factors resulting in the flight vehicles failure.
As a result, the wind tunnel test must be carried out to study the transonic speed flutter properties of flight vehicles [1, 2, 3].
Using the flutter test of the component model to check the flutter properties of flight vehicles are workable when the component-to-component structure is not coupled or coupled in a low degree [4].
FSS Mechanical System.
Objective of this wind tunnel test is to test the control capacity of FSS control system to the model and examine the flutter properties of the model when the Mach number Ma=0.70 and 0.90.

On account of that the research about the cryogenic MQL cutting technology is still in its initial stage, many problems need to be solved, such as that the cutting properties of materials are different in cryogenic MQL cutting conditions, and the parameter optimization in cryogenic MQL cutting various materials is insufficient.
The turning experiments were performed by single factor method.
The bars were cleaned prior to the experiments by removing approximately 0.5 mm thickness of the top surface of each bar, in order to eliminate any surface defects and wobbling that can adversely affect the machining results.
At the same time, due to process vibration and other factors, the surface roughness will decrease.
All of these factors will increase the tool flank wear, resulting in tool failure quickly in dry cutting mode; at a high cutting speed conditions, the durability of the tool is higher in cryo-air cutting than that of dry cutting.

Cooling, lubricating and other functional properties of cutting fluid could not be effectively applied in the cutting zone at the moment of heat generation.
Coaxial positioning of wheel to the ring and absence of rigid mechanical connection between wheel housing and abrasive segments leads to the fact that vibrations of grinding spindle will not be transmitted to workpiece and will not affect geometry of ground ring.
The most influencing the coolant pressure factor was the speed of grinding spindle.
Khudobin, Cooling–lubricating agents, used in grinding, Mechanical Engineering, Moscow, 1971
Brliner, Cooling–lubricating technological agents for metal cutting, Mechanical Engineering, Moscow, 1986.

Typical supplementary cementing materials are fly ashes, slag, silica fume and others wastes with pozzolanic properties [4,5,6].
The properties of secondary and recycled aggregate are in many ways different from those of primary aggregate and this could lead to varying properties when incorporated in concrete composites.
The mechanical properties of recycled aggregates are generally lower than primary aggregates and therefore limit their uses, sometimes, to low-value applications.
However, it is now generally accepted that not the mechanical properties but rather a combination of surface texture, mineralogy and particle shape of aggregates and optimisation of the mixture design that influence the composite performance.
Mechanical concrete properties such as compressive and flexural strength were studied.

Almost all of this work to date has assumed that the modal properties of the bridge do not vary with amplitude of oscillation (i.e. the vibration is linear).
Eccles et al. [7] conducted experiments on a series 2 Title of Publication (to be inserted by the publisher) of concrete beams to examine the non-linear amplitude-dependent modal properties of the beams.
The drawback with using time-frequency relationships to assess changes in non-linearity with damage is that damage affects damping properties [2].
Severn: Assessing the dynamic properties of prototype structures by hammer testing.
Aves: Impact factors for simple concrete bridges.

This study is also expected to contribute towards the development of cost efficient alkali activated binder that will result in a good mechanical property which majorly depends on the compressive strength.
The chemical and physical properties of the UPOFA in this study are provided in Table 1 and Table 2, respectively.
An overview on the influence of various factors on the properties of geopolymer concrete derived from industrial by-products.
Synthesis of geopolymer from large amounts of treated palm oil fuel ash: Application of the Taguchi method in investigating the main parameters affecting compressive strength.
Engineering and transport properties of high-strength green concrete containing high volume of ultrafine palm oil fuel ash.

To obtain the Ca-TZP materials with excellent mechanical properties related to the transformation toughening mechanism, the extremely fine microstructure with tetragonal grains of ~0.1 μm in size is required.
It was further shown that the crystallisation of zirconia polymorphs is affected by both a mineralizer solution and conditions of thermal treatment [10-11,6].
Little attention has been paid to show technological properties of the resultant nanopowders.
So, it is confirmed that the temperature, pH and mineralizer are the crucial factors influencing the morphology of calcia-zirconia nanoparticles obtained during hydrothermal treatment.
The temperature, pH and mineralizer are indicated as the factors controlling the appearance of elongated calcia-zirconia crystallites during hydrothermal treatment.

In the past, the research has been paid more attention to the design way and the mechanics property of the equal-loading joints, few to the residual stress.
The relationship among the plate thickness 2t, reinforcement height h, half width of reinforcement w0, weld toe radius r geometry parameters and the weld toe stress concentration coefficient Ktoe, the weld root stress concentration coefficient Kroot has been established: Ktoe=1+αr0.403th+t-1.031 (2) Kroot=th+t+β (3) where α，β are both the shape factors.
The physical and mechanical property parameters of CF62 can be seen in the reference [9] while the same parameters of stainless steel 316L can be seen in the reference [10]. 4.
In short, the thicker joint has the larger residual stress especially in the heat affected zone.
Simulation of 3D Residual Stresses Field of Multi-pass Welding by FEM, Journal of Mechanical Strength.

This relation yields only an approximate value since the heating rate, the attempt-to-escape frequency factors, and the thermal conductivity of the material, affect the exact value of Tm in the material.
In fact, many TL materials also demonstrate OSL properties [34].
Kearfott, Characterization of the glow peak fading properties of six common thermoluminescent materials, Appl.
Rhodes, OSL properties of NaCl relative to dating and dosimetry, Radiat.
Rafique, The optically stimulated luminescence (OSL) properties of various known thermoluminescent (TL) materials, Appl.