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The utilization of laser is wide and namely in the field of heat cutting of materials where this method is the most progressive. The optimization of all parameters of cutting arrangement is the most important for achievement the best quality of cutting area; it means rate, power, pressure, and focal distance of laser. Suitable setting of various parameters can influence the quality of cutting area...
The mechanical properties of parts prepared by casting are dependent mainly on their microstructure. Grains size, size of dendrites and dimensions, shape and quantity of structural defects has important influence on final mechanical properties of these parts. Image analysis is an appropriate tool which can be use for qualitatively and quantitatively materials microstructure characterization [1,2]...
High-temperature constructional parts of aircraft engines and energy units are exposed to high dynamic stress (fatigue processes and creep) and various temperatures in dioxide-corrosion condition (hot corrosion, oxidation and erosion). The improvement of aero-engine and turbine efficiency is possible through the increase of temperature in front of turbine. This requires the use of heat-resistant and...
Nickel-base superalloys, strengthened by the ´ phase dispersion, presents the typical precipitation strengthened alloys. In creep testing conditions, particles of secondary phase can be effectively blocks of dislocations movement at high temperatures as well. However, particles must be sufficiently stable with respect to coalescence, it means the average distance between them increases very slowly...
The structure of ductile cast iron is formed from graphite and basic metal matrix, which is composed from pearlite, ferrite and alternatively their mixture and other structural components (steadite, inclusion). The cast iron with ferrite matrix is characterized by quite high plasticity, toughness, and good workability whereas the tension strength is lower. The ferrite structure is reached by means...
Nanostructured materials have been noted a massive scientific progress and industry development over the last few decades. The nanostructured materials can be produced from ceramics, metals, polymers, etc. The nanocomposites are the one type of nanomaterials. The nanocomposites with metal matrix and nanoparcicles coating have been prepared by means of electrodeposition process. The chemical composition...
The cast aluminium alloy A357 has been widely used in aircraft industry. Particularly, due to well known performance characteristics of aluminium alloys like strength/weight ratio (specific strength). This contribution deals with the effect of different heat treatment on mechanical characteristics of A357 cast aluminium alloy. As relevant parameters were chosen yield strength, ultimate strength, elongation...
Determination of chemical composition of advanced materials as nanoceramics using the microwave digestion and atomic absorbance spectroscopy is discussed. The technique of microwave-assisted digestion is used for preparation of the materials for analysis of chemical composition. The exact chemical composition is one of the most important factors for prediction of material behavior even at severe reducing...
The paper summarizes the results of structure analyses focused on differences in the technologies of manufacturing AZ91-alloy castings. The following technologies were used: A) die casting B) gravity casting into ceramic moulds As to their shape complexity the two castings are similar and are of roughly the same wall thickness. The die casting was selected form the manufacturing process while the...
The problem of transportation services of the urban area i prasented in this paper. Solving of this problem can be made through the CW method. Some modification of CW method are specified in this paper. The original CW method may be used to solve the solutions of traffic nodal points transpotation services. (Not to solve solutions of edges transpotation services.) Our modifications of CW method take...
The reverse logistic take a new dimension of logistics in 21 century. It is the last part of whole logistic chain. Some specifications of the reverse logistic, especially of the waste logistic are presented in this paper.
This topic dealt with new view on materials selection for railway vehicle from side of fire safety level according DIN 5510. LCC will be used as a tool for optimum determination between life cycle cost and fire safety level of vehicle.
The new energy law has been liberating stepwise market with electrical energy in the Czech Republic since 2001. This market has been liberated completely since 2006. The expansion of electrical appliances with nonlinear characteristic in distribution networks LV (such as televisions computers, copiers, compact lights) affects strong debasement of quality parameters of the supplied electric power....
The Power Quality Monitoring becomes more and more important because of the liberalisation of the energy markets. Electrical energy becomes product and customers want quality product for their money. There are a lot of international (European) and national standars connected with power quality. IEC 61000-4-30 very precisely defines how should be required power quality parameters evaluated and also...
The new Acts No. 180/2005 Coll. supports the utilization of wind energy in the Czech Republic. This act decrees the mandatory purchase of electricity produced from wind power plants. A purchasing price of produced electricity is adjusted according to price decisions of the Energy Regulatory Office. The purchasing price is adjusted in this way so that the investment recovery (incl. operating costs...
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