The present work is motivated by the tremendous interest in the functionally graded materials (FGMs). The properties of FGMs change gradually with the position. The property gradient in FGMs is caused by a position-dependent chemical composition, NS OF FGMs microstructure or atomic order. The overall properties of FMGs are unique and different from any of the individual material that forms it. One unique characteristic of FGMs is the ability to tailor a material for specific application. There is a wide range of applications of FGMs and it is expected to increase. In this paper we will make a brief survey of the most distinguished properties and some of the applications of FGMs.
Machines. Technologies. Materials.
Vol. 8 (2014), Issue 3
Table of Contents
the theory of cumulative fuel consumption has been presented. The example of interurban bus research results have shown the way of getting to mathematical model of cumulative fuel consumption and the intensity of cumulative fuel consumption. The high value of pres- cience quotients is not a case- similar values were obtained in various different cases.
The traveling salesman problem (TSP) is one of the most studied problems in management science. Optimal approaches to solving traveling salesman problems are based on mathematical programming. But in reality, most TSP problems are not solved optimally. When the problem is so large that an optimal solution is impossible to obtain, or when approximate solutions are good enough, heuristics are applied. Two commonly used heuristics for the traveling salesman problem are the nearest neighbor procedure and the Clark and Wright savings heuristic.
In this paper will be present using of the solver software and principles of TSP for optimal solution of vehicle routing for domestic bottled water and different juices in the different parts of the Republic of Macedonia.
Effective deployment of ITS technologies depends in part on the knowledge of which technologies will most effectively address the issues of congestion and safety. Thus, it is important to understand the benefits or risks of both existing and emerging technologies. Based on documented experience locally and throughout the country, ITS deployments in urban areas have the potential to offer the following benefits:
• Arterial management systems can potentially reduce delays with the implementation of advanced control systems and traveler information dissemination.
• Freeway management systems can reduce the occurrence of crashes, increase capacity, and decrease overall travel times.
• Freight management systems reduce costs to motor carriers with the implementation of the commercial vehicle information systems and networks.
• Transit management systems may reduce travel times and increased reliability with automatic vehicle location and transit signal priority implementation.
• Incident management systems potentially reduce incident duration and offer numerous other benefits.
There is a wide range of benefits that can be obtained from ITS deployments. For example, fuel consumption, travel time, and delay can be reduced. ITS deployments can also result in higher travel speeds, improved traffic flow, and more satisfied travelers for all modes.
IMPROVED ADHESION STRENGTH, CORROSION AND WEAR PERFORMANCE OF PLASMA-SPRAYED COATINGS DERIVED FROM PVD FILM-COATED POWDERS — CONCEPT AND PRACTICEpg(s) 28-31
Technique and equipment for plasma spraying of wear-resistant and corrosion-resistant coatings with enhanced adhesive strength was developed. Ceramic powders coated metal thin films were used for plasma spraying. Optimal conditions for deposition of the metal films on the particles of alumina powder (40…63µm fraction) by PVD process were obtained. Deposition of two- layer films on the powder particles was carried out. The first layer was titanium and the second layer was aluminum or copper. The titanium as adhesively-active element capable of wet alumina is necessary for increase the adhesion strength vacuum films as well as plasma sprayed coatings.
A special plasma-spray gun with external arc working in a mode of laminar plasma argon jet generation was designed. Such regime provides melting of the refractory ceramic core, saving metal films as well as localization of thermal effects during spraying process.
The results of testing coated specimens confirmed that the developed technique improves the physical and mechanical properties of the plasma sprayed composite coatings. The sprayed composite coatings were compared with coatings sprayed using pure alumina powders in terms of adhesion, wear and corrosion properties. The shear adhesion strength increases up to about 1.9 times, the wear resistance increases about 5 to 7 times, the corrosion resistance increases about 2.5 to 5 times.
The shear adhesion strength was measured at tension of coated specimen at room temperature by developed adhesion testing technique. The substrate was flat and dog-bone-shaped. The substrate with rectangular cross-section was partially coated with plasma- sprayed coating. The specimens were tested in uniaxial tension under displacement control. The tensile specimens were loaded to adhesion delamination of the coating. Sprayed coating was detached as a result of shear interface stresses.
Various experiments are performed for detecting engine characteristics. In these experiments some values are kept constant; for example, engine power, torque and fuel consumption is measured as the values, depending on these motor characteristics are obtained by making a calculation. In this study, the simulator program is designed for analysis and synthesis of engine’s characteristics. The program , according to data obtained and entered the engine curve to be drawn (numerical or graphical), to examine the changes interactively based on input parameters, calculations are done for the value cannot be measured, and many other features. Thus, in order to obtain characteristics of the engine or in the expression-related issues provides great convenience for understanding and education.
The paper presents a discussion of the combustion processes in the engine piston, in terms of ignition delay. The problem of the physical and chemical ignition delay is discussed and equations which allow the calculation of ignition delay based on the theory of com- bustion processes are presented. The paper proposes the use of a catalytic coating in the combustion space in order to shorten the ignition delay. The results of studies made on single diesel engine are displayed. Studies have confirmed a significant effect of the catalyst on the combustion process and shortening the ignition delay. Internal combustion catalyst used as a coating made of ZrO2 activated Pt and Rh deposited on engine valves, caused a shortening of ignition delay of about 1 – 3 degrees of crankshaft rotation.
the contribution deals with problems of measurement indicated pressure of internal combustion engine. Indicated pressure measurement allows better monitoring of change state quantities during implementation working cycle of internal combustion engine.
Measurement is realized with the mobile unit on the vehicle under the specified mode, the real conditions of transport, as well as on brake bench in the laboratory. By analysing the results of experiments can be more precisely to quantify efficiency of power transmission and energy flows in the drive mechanism of the vehicle.
SIMULATIONS OF NONCONVETIONAL DESINGNES WITH REGARD TO COMPRESSION ABILITY FOR USE IN STIRLING ENGINEpg(s) 40-43
This paper deals with comparing three types of non-conventional mechanisms of Stirling engines. It is a wobble yoke mechanism, a special type of wobble yoke mechanism and mechanism with ring. The mechanism with a ring was designed as another possible mechanism for structural design of wobble plate in projekt Nonconventional engine FIK –Stirling. The aim is to compare the relative movement of two consecutive pistons in the Stirling engine system and thus evaluate the course compression that arises in one interconnected system of this engine. The paper deals with the dynamic simulation of these mechanisms. The dynamic simulations were made in Autodesk Inventor sofware.
It is important to load and fix goods in railway wagons in well done way to reduce the number of accidents on the railway.
The bad way of loading and fixing of the goods in the railway wagons can bring a very dangerous results as a damage of the transported goods or accident of the train. This paper deals with the analysis of the railway infrastructure parameters which affect the well done way of loading and fixing of goods in railway wagons.
Transit of surface waves through defects in steel surfaces has been viewed in this paper. The form of registered signal is changing as result of complex wave processes in the area of defects. The received signals are digitized and phase-spectral analyses are have been made. If there is a defect in the surface of the samples it shifts the phase of the Rayleigh wave. The phase shift depends on the size of defects. The results obtained can be used for the creation of innovative technologies with improved resolution for testing of surface and subsurface defects in the practice of non-destructive testing.
The aim of this work is to extract modal parameters of a light aircraft wing. Modal parameters like natural frequencies, and mode shapes characterise the dynamic response of a structure and can be used for determining of the wing divergence and flutter. The CAD (Computer-Aided Design) model plays a pivot role in the design and development phases of an aircraft. Creating drawings, preparing reports of assembly and part drawings, preparing bill of materials, the aircraft design becomes easier and faster with the use of CAD system.
CAD model has to be imported in FEM (Finite Element Method) software, and so it can do FE model, which have to be solved. In this work a light aircraft wing is modelled by SolidWorks software. After that the CAD model is imported in ANSYS Workbench. The FE model is generated and solved by using ANSYS Workbench. The first six natural frequencies and mode shapes are shown for the proposed light aircraft wing.
We have tested typical samples of fuel (diesel, gasoline, technical gasoline and a mixture of unknown fuel). For fuel analysis we have used an analyzer IROX DIESE with an in-built infrared interferometer of Michelson’s type. The results proved that within a wavemeter from 650 up to 1800 cm-1 for each fuel there is a typical infrared spectrum. This spectrum can be compared with human fingerprints. It is possible to positively identify the majority of fuels with the usage of these spectra. Moreover in case of unknown mixture, it is possible to use these spectra for determination of their mutual ratio.
Postal network is the most developed and complex logistical infrastructure in the world. The complexity is determined by the number of participants, which either require or perform postal services and by manipulating with a large number of postal items handling billions of them on daily basis globally. A basic request is that the shipment is transferred safely and on time to the recipient. A mass production, many sorting points in the supply chain and variety and stochasticity of delivery addresses are aggravating circumstances for this goal fulfillment. Accordingly, postal operators need the most advanced technological systems for sorting and processing. This paper proposes the concept of addressing based on the three levels of postal units and the software application created for the routing of postal items in the system of this kind.