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This article offers a novel method of gold nanoparticles preparation which increases their obsevation feasibility. Gold nanoparticles were prepared by sputtering of 6 nm of gold on surface of NaCl crystals and consequent annealing. Gold nanoparticles were separated from the substrate mechanically in the ultrasonic bath. The preparation of gold nanoparticles on NaCl substate is extremely versatile. It enables to descibe size and shape of the individual nanoparticles much better than usually used SEM and AFM techniques, it enables to see the lattice arrangements and also to do more precise chemical analysis without the influence of the substrate. It is applicable for characterization of temperature-, time-, chemical composition- and atmosphere influence on morphology of gold nanoparticles. The nanoparticles were observed by HRTEM. In our case, the influence of carbon addition on morphology of gold nanoparticles was studied by sputtering one or two carbon interlayes in the gold layer. It was found out that one carbon interlayer slightly descrease nanoparticle size. On the other hand, two carbon interlayers lead to formation of irregular large shapes of the gold particles.

It is well known that the susceptibility of steels to hydrogen embrittlement is markedly dependent on hydrogenation conditions of samples. In this contribution are presented key results of relatively extensive studies oriented to examination of the effect of electrolytic hydrogen charging conditions (charging time and current density) on the hydrogen embrittlement of steels evaluated by the slow three point bend tests, micro- and macro-hardness tests. Various kinds of industrially produced hot rolled steel strips were tested (structural steel, dual phase and HSLA steels). The major aim of this study was to determine the hydrogenation conditions that do not result in the formation of defects such as microcrack or voids (in terms of absence of defects found by using optical microscopy) during hydrogen charging process.

Titanium-aluminium base nanomultilayer (NML) coatings are deposited by cathodic arc evaporation using pure titanium and aluminium with eighteen percent silicon cathodes. Each multilayer Ti-Al-Si-N structure consists of 49 bi-layers with different thickness. The external deposited layer is with five times longer growing period. The coatings are deposited at the pressure of 2 Pa and the substrate temperature of 400 °C. Polished steel discs (Ø 20 mm × 5 mm thick) are used as the substrate material.
This article presents an investigation of the surface morphology and mechanical properties of the coatings, particularly the adhesion and nanohardness. The AFM analysis indicates that the coatings are dense, with an average surface roughness in the range of 33 / 58 nm. The coating with the smaller value of average surface roughness exhibited a maximum hardness of 43 GPa. High calculated value of plasticity index (H/E) is 0.104. The scratch test results revealed that all the investigated coatings have very good adhesion in the normal loading interval from 1 N to 40 N.

This work is focused on the description of the influence of the particle size of nickel on the synthesis of NiTi shape memory alloy by reactive sintering with high heating rate (300 °C.min-1). It was found that coarse nickel powders undergo only a limited thermally-activated reaction. On the other hand, too fine powders support the low-temperature (500-800 °C) diffusional formation of Ni-Ti intermetallics which could then suppress the rapid thermally-activated reaction. The optimum powder fraction of nickel to obtain the material with the lowest porosity and fraction of undesirable Ti2Ni phase is 25-45 μm.

The article deals with application of knowledge from lubrication of healthy spherical joints into hip joint endoprosthesis. As the observed most important physical parameter it was selected the coefficient of friction responsible directly for lifetime of the endoprosthesis. The article describes as well as experimentally verifies the idea of additional lubrication of hip joint endoprosthesis.

This paper completes a design of power monitoring system of machine tool based on MSP430F149 microcontroller. This system is mainly divided into four modules: the electric energy information input and processing module, electric energy metering operation processing module, Single-Chip Microcomputer system internal data processing module, and PC memory module, respectively. The voltage transformer and current transformer collect voltage signal and current signal respectively, which were inputted deferentially to the ATT7022A voltage channel and current channel, to achieve electric energy information input and processing. The special measure chip ATT7022A measures the three-phase active power, reactive power, apparent power, active energy and reactive energy to meter and operate electric energy. MCU system processing module communicates with ATT7022A chip via the SPI bus interface by using the 16 bit MSP430F149 microcontroller. The establishment of database model and database table using the relatively practical method of entity-relationship achieves PC internal data memory module. In addition, the fabrication of PCB circuit board and software writing are also introduced in detail in this paper.

This article deals with simulations of the welding process for applications of practice using SYSWELD software. Simulation of welding at the repair of high-pressure gas pipeline with steel sleeve with composite filling is presented in this paper. Two welds connecting the distance ring and gas pipe were simulated. Structure of programme SYSWELD and repair of high pressure gas pipeline with steel sleeve is described in theoretical part of article. Preparation of boundary conditions for numerical simulation on real sample and numerical simulation of welding is in experimental part. Thermal fields, residual stresses and hardness were simulated. The results of the numerical model, which are listed in article except for residual stresses are compared to real experiments. This article mainly describes the numerical simulation capabilities in welding simulation programme SYSWELD.

The automotive brake (clutch) disks are produced almost exclusively from flake graphite cast iron. These disks must fullfil a variety of strictly controlled parameters - high wear resistance, hardness, resistance against thermal fatigue and good thermal conductivity. The microstructure is created by the IA graphite in pearlite matrix. The isothermal hardening to ausferrite structure (AGI) was made in order to improve standard flake graphite cast iron properties. New methods and procedures of non-destructive structuroscopy, magnetoinductive, ultrasound and magnetic spot methods were used to compare material properties of flake graphite cast iron and ADI. By these methods, elasticity modulus, strength and hardness were evaluated. The resistance against thermal fatigue was evaluated by the Eichelberg factor. In this contribution, Material parameters of standard flake graphite cast iron and AGI are compared. The heat treatment of brake disk matrix from AGI can considerably improve their material parameters, especially durability.

The aim of this work is concerned with a problematic adhesion of polymer materials on the surface of processing tools. Such phenomenon plays especially an important role in production of rubber components which creates an additional and considerable costs associated with mold cleaning. However, the origin of contamination is still not fully known yet. From production point of view, the attention should be paid to three fundamental aspects: processed material, material of processing tool, and processing conditions. This study describes the results of mold's surface contamination during processing a rubber compound in terms of material and surface treatment. A method of spectral analysis in terms of FTIR was used for proper examination of this problem.

TRIP (transformation induced plasticity) steels are low alloyed steels with multiphase microstructure consisting of ferrite, carbide-free bainite and retained austenite. They are typically produced by thermo-mechanical treatment, which involves the hold in bainite transformation region. The hold ensures enough bainite in the final microstructure and also helps to stabilize higher amount of retained austenite. Due to transformation induce plasticity effect; TRIP steels possess very good combination of high strength and high ductility. In response to industrial demands, C-Mn-Si and C-Mn-Si-Nb TRIP steels were subjected to thermo-mechanical treatment with continuous cooling which corresponded to real rolling mill processing of the steel with similar chemical compositions. Typical TRIP microstructures with 10-15% of retained austenite were achieved for both steels after optimization of cooling schedules. However, cooling by two different cooling rates had to be applied to C-Mn-Si steel to obtain the convenient microstructure. Beneficial effect of Nb micro-alloying on low sensitivity of TRIP steel to variations in cooling parameters has been found out. Mechanical properties of the most convenient microstructures were very promising, ultimate tensile strength reached 850MPa with ductility A5mm around 25%.

Many solid materials are subjected to structural changes, e.g. phase transformations within temperature change. These phase transformations are usually accompanied by a significant change in particular volume. The change in volume of a solid material is measured by the corresponding change in length of a specimen of the material. The experimental method which is based on measurement of volume/ length change during linear heating or cooling is dilatometry. Dilatometry is characterised by the linear thermal expansion coefficient which can be described as the relative length-change divided by the corresponding temperature interval. The basis of the thermal expansion of crystalline material is related with the function between interatomic forces in crystal lattice. This paper investigates the effect of temperature on structural changes within austenitic stainless steel that underwent different heat treatment before the measurement.

The article deals with experimental measurements of force effects that direct blow develops taekwondo sportsman. Power effects are captured using a high speed camera. Experimental measurements have confirmed the results of many scientific papers that deal with the measurement of the force effects of combat sports athletes, etc. There are described some methods that are used in medicine and biomechanics to view internal organs or injury detection.

In particular, the quantitative and qualitative results of the technological process are in most cases determined by the level of finishing operations, which include in particular grinding. It is characterized by high precision, the accuracy of geometric shape and generally very good quality surface. One of the factors to achieve the desired quality of finished surfaces, in particular, knowledge of the effect of temperature of the contact surface of the grinding wheel and the ground. In the article is the methodology of the quantification of the impact of cutting parameters on the temperature of the grinding. Another requirement is the right choice of other cutting parameters, to guarantee the achievement of the required accuracy dimensions and shape, increase performance and decrease the temperature of the contact of the cut surface with a grinding wheel.
The result is the desired surface integrity and the exclusion of undesirable residual stress in the lustre of the surface. In the case of the quantification of the individual characteristics of the grinding on the optimization of the grinding process, it is possible to achieve this objective

A mechanical treatment of an adherent before an application of adhesives is one of key factors influencing resultant strength of an adhesive bond. A grit blasting belongs among one of the most often used methods of the surface treatment. A resultant structure of blasted adherent and also parameters of the surface roughness can be changed during the blasting by a suitable choice of many parameters among which a material and a size of abrasive particles, a distance of an air jet and a blasted material, a size of the jet, an air pressure and an angle of abrasive particles impact can be ranked. This experiment describes an injector system of grit blasting using basic abrasives - corundum and glass ballotini. During grit blasting of common steel adherent it came to the change of the impact angle of the abrasive particle in a range from 75° (a perpendicular angle) to 10°. Different impact angle led to different roughness parameters and to various structure of the adherent surface which was evaluated by an electron microscopy. Subsequently, it came to experimental description of the strength of adhesive bonds which were created by adherents whose surface was grit blasted under various impact angles of abrasive particles.

Rare earth elements in magnesium alloy enhance mechanical properties, corrosion resistance, and heat stability up to 300 °C. Those enhancements with low density of magnesium determine this alloy for aviation and automotive industry. Magnesium alloys are also considered as materials for biodegradable implants. In this field there are required good mechanical properties and fair corrosion rate. In this work, WE43 alloy prepared by powder metallurgy with different conditions of sub-processes is prepared. Milling, cold uniaxial pressing, spark plasma sintering (SPS) and extrusion processes are used for sample preparations. Structure and mechanical properties of prepared materials are characterized.

Currently at our department - Department of Engineering Technology - Technical University in Liberec), we are under-tracking properties of copper alloys. This article is dedicated of the brass (Cu-30Zn), which is used for production of decorative castings. With production of decorative castings deal various foundries in the Czech Republic. The staff of these foundries for long periods gained a lot of experience in metallurgy and preparation of the copper alloy melts. In terms of our foundry there is little available literature data, which would characterize the crystallization and solidification of castings produced from single and multicomponent brass. Our department is involved in research of copper and its alloys. This article contains a description of crystallization of copper alloys (70%) - Cu-30Zn and proving phase analysis structure of the production of test casting shape of desk in the sand mould.

Paper deals with problems of nanoparticles and nanomaterials applied in technical practice. In this time, we are looking for and examining ways of their best properties utilization. When being applied on the base material (metal, plastic, glass, incl. paper, cloth, etc.) In the form of very thin layer, then the base material can obtain very different properties, mostly advantageous, including improvement of their mechanical properties. To obtain these properties, it is necessary to apply nanomaterials in the form of very thin layer and for this purpose we need extremely fine granular nanoparticles that can be produced by means of fine milling technology. Resulting size, structure and shape of individual particles grains have the deciding influence on the successful application of these nanomaterials layers.

Austenitic stainless steels are widely used for various biomedical applications because of their biocompatibility, high resistance to uniform corrosion and suitable mechanical properties. However, they are prone to local corrosion in aggressive halides environments. This article focuses on the effect of fluoride added to physiological saline solution (0.05 % NaF resp. 0.5 % NaF + 0.9 % NaCl solution) and on the effect of fluoride containing mouthwash (0.05 % NaF) on corrosion resistance of AISI 316L surgical steel. Evaluation is based on results of 42-days exposition immersion tests performed at the temperature of 37 °C (REM observation of attacked surfaces, mass losses of specimens) and on the results of the electrochemical cyclic potentiodynamic polarisation tests performed in the same solutions at the same temperature.

Iron has a low solubility in aluminium solid solution even at elevated temperatures and forms brittle intermetallic phases with needle-like or platelets-like morphology when it is produced by conventional casting technologies. These phases have a detrimental effect on mechanical properties. Therefore with increasing significance of recycling and also amount of aluminium scrap that needs to be recycled, it is necessary to find a promising ways of processing such waste materials. Powder metalurgy leads to intensive microstructural refinement, increases solid solubility of alloying elements and overall to improvement of mechanical properties. Hence, it belongs to promising alternatives for proccesing aluminium materials with increased amount of iron. Aluminium alloy with 17 wt. % iron was prepared by centrifugal atomization and consolidated by spark plasma sintering followed by hot extrusion. The microstructure and phase composition of compact samples as well as mechanical properties were studied. Fine microstructure has been achieved by centrifugal atomization and consolidation by spark plasma sintering in combination with hot extrusion. Compression strength was 565 MPa with remarkable ductility reaching almost 35 %.

This paper investigates the influence of Artificial Neural Network (ANN) architectures on its prediction capability when machining nickel based super alloy. The ANN was employed to determine surface roughness parameter Ra through cutting conditions, tool wear and process monitoring indices such a cutting force components. The ANN structure was optimized by methods like a reduction of input vector parameters, dimensions of input data pattern, combined reduction and modification of hidden layers. Calculated and experimentally measured values were compared for each optimized ANN model. The work concludes that optimization of ANN has significant influence on prediction capability and accuracy for the task proposed.

The article presents comparison of optimization methods applied to operation of the heating plant. Optimizing problems are possible to solve with using of methods of the linear programming (LP) or nonlinear programming (NLP). In the paper method of differential addition (LP, NLP), method of characteristics (LP), simplex method (LP), method of Lagrange multipliers (LP, NLP) and method of hyperplane in n - dimensional space (LP, NLP) are presented from point of view of requirements for designing and modifications of the program, requirements on system memory and computation time, comparison of the optimizing methods for loading of the thermal power machines and devices.

In the production of polymer parts, great emphasis is placed on the quality of polymer product in terms of dimensional accuracy and optimally surface quality. Achievement of high surface quality of injection molded products correlate to the high surface quality of core or cavity in injection molds. This surface is copied during injection of polymer material. The kind of polymer material and its rheological properties can strongly influence this surface copying. Production of cores and cavities takes in the manufacturing process a considerable part of time, where some finishing technologies are more economically and time consuming than other processes. Thus, it is necessary to choose an appropriate finishing operations considering cost of injection mold, which is reflected in future price of polymer product. This paper experimentally examines the influence of the surface quality of mold cavities and rheological properties of polymer on the surface quality of injection molded product.

This article deals with the influence of different specific pressures on the heat flux from the casting into the mould. The determination of the heat flux at different crystallization conditions will be the basis for the simulation calculation of the solidification with the crystallization under pressure.
The article presents the results of the measured temperatures inside of the mold and casting by influencing of the crystallization pressure of 100 MPa. For comparison, results are also presented in gravity cast specimens. Also are presented pictures of microstructure that were observed near the surface of the casting. On the basis of the measured temperatures inside of the mold are calculated as a value of the heat flow from casting into the casting mold. The results of heat flow correspond with the evaluation result of the microstructure.

From the viewpoint of residual stresses and microstructure of ground surface, Inconel 713 superalloy is an attractive material since it is frequently used in high temperature gas turbine applications where residual stresses are relevant for service life. The goal of this contribution is to find whether there exists a relation between grinding parameters and final surface integrity parameters such as residual stresses, roughness, crystalitte size, and generally, microstructure. Highly productive creep feed grinding has been applied to produce both simple flat areas and complex fir three blade root. It has been found that the used grinding method lead to very thin deformed layer on the surface with compressive residual stresses and fine crystallites. Moreover, the detailed analyses have been carried out in order to pinpoint plausible reasons behind crack origination.

The article is deals by an introduction to the theory of impact load for thin plates. This is the plates that are characterized by a structure which is bounded by upper and lower surface plane. These surfaces are spaced by a distance h, which is substantially smaller in comparison which other dimensions of the plate (a × b). The impact causes a deformation of the plate which is vibrated. The deformation is only within the limits of Hook's law. Therefore there is not permanent deformation of the plate. In the plate is induced shear stress, bending stress and shear forces. The second part of the article is focused on the numerical solution of thin isotropic aluminium plate which is made from AL 99.9. This plate has a dimension of 100 × 100 × 2 mm. It was solved the deformation of the plate after the impact load which were produced in the centre of the plate by FEM in software ADINA. By results was a graph of the deformation, velocity and acceleration of response wave in the material.

This paper aims to design a control jig for cutting inserts measurement. These inserts are made from standardized inserts by grinding. The control jig is intended to be used on two different types of measuring devices and it has to meet the functional requirements of these devices.The intoduction describes specific functional requirements on the jig, provides information about measuring devices and examples of cutting edges grinded on inserts. Next part describes the design of several variants of jig parts and reasons for their application. Paper is focused specifically on design of jig body variants, description of measuring arm and the way of clamping of inserts in the control jig. The measuring range is described for each of proposed variant. In the closing part of the article particular variants are compared according to their suitability, stability during measuring and range of serviceability for measuring of the inserts.

In this paper the mechanical behaviour of structural two-component epoxy adhesives in T-joints is experimentally investigated. Laboratory experiments were performed on standardized test specimens of structural carbon steel S235J0 made according to standard ČSN ISO 11339.
The aim of experiments was to confirm or disprove a hypothesis about a possibility to increase the adhesive bond peeling strength by means of an interlayer from glass fibres.
The research was focused on an effect of an improving a resistance of the adhesive bond stressed by peeling by adding an interlayer created by fabric from glass fibres. The testing of these properties was performed in accordance with standard ČSN EN ISO 11339. An epoxy resin was used as the adhesive for connecting adherents created by sheets of steel. The fabric from glass fibres of the type E in a plain weave was added as the reinforcement for creating the composite bond. For optimization of properties of the composite bond it was used various weight in grams of fabric in the extent of 80, 110, 160, 220 g/m2.

In the work, there are noted experimental results aimed at determination of influence of initial microstructure of the steel S355, that was exposed to different temperatures of intercritical annealing, on its resistance against cyclic loading by number of cycles needed to fracture the samples, loaded by stress amplitude σa = 500 MPa. Intercritical annealing at temperature ranging 740-840°C was carried out on a bar with the same thickness as the steel sheet in received state (B=9mm). Fatigue tests were realized on 1,2mm thick specimen cut from subsurface and middle area of initial thickness of the plate, where a banding structure occurred, thickness ∼1,5 mm in the received state. It was discovered, that samples with microstructural banding have higher fatigue resistance independently on temperature of intercritical annealing.

Grinding is currently still an important method for surface finishing. At FPTM JEPU is realized the research, which deals with this issue. There are carried out experiments with grinding various materials under different conditions and then are evaluated the selected components of the surface integrity, which are generally roughness Ra, Rz and Rz, material ratio curve (Abbott Firestone curve) and also obtained roundness. This article deals with grinding nickel alloy Inconel 718, when selected cutting grinding conditions were used and subsequently the surface roughnesses Ra, Rz and Rt, the surface profile and the material ratio curve were measured and evaluated.

The article deals with numerical simulation of induction heating process as a coupling of electromagnetism and heat transfer with the scope to surface temperature optimization. The article presents how the position of the inductors used in the induction heating process influence the resulting temperature of heated surface. The scope of the article is to show methodology to optimize surface temperature by numerical approach.