Machines. Technologies. Materials.
Vol. 8 (2014), Issue 5

Table of Contents

  • CELLULAR RADIO CHANNEL CARRIER AGGREGATION MOTIVATION AND BENEFITS OVERVIEW

    pg(s) 3-5

    The main challenge in the evolution of cellular networks is providing increased channel capacity and data rates. Mobile operators are obligatory to boost the researching of methods for enhancing the spectral efficiency in response to the growing needs for better connectivity and signal coverage. The engineering of transmitters and receivers should be processed in a very precise manner as a matter of frequency effectiveness. An essential competitiveness is achieved having the combination of carrier frequencies as elements of one whole traffic trunk. Multicarrier techniques provide fulfilment of user requirements in the face of continuous on-line actions, fast file sharing and permanent Internet connectivity. Carrier aggregation in radio channels is seen as sophisticated technique for improving frequency usage assuring higher throughput and capacity.

  • VERTICAL INNOVATIONS NECESSARY FOR INCREASING THE ACCESSIBILITY OF ICT ACADEMIC PROGRAMMES

    pg(s) 6-9

    The specifics of the ICT labour market require continuous and rapid qualification and retraining of staff. At the same time, the existing conventional educational structure does not allow the rapid adaptive retraining of specialists as the majority of university programmes are based on a fixed set of foundation courses and a modular education system. This paper describes a new concept for academic curriculum structure that aims at providing open access to the curriculum excluding the historical relationships in forming the foundation of knowledge, and opens the market of educational services to other providers, such as colleges, private academies and practical hands on experience. The presented model encourages competition and does not allow dividing the operators of educational services into new entrants or players in a dominant position, thus the concepts found in real terms realisation of new undergraduate program in Network Engineering at New Bulgarian University.

  • A METHOD OF VEHICLE-PEDESTRIAN ACCIDENT RECONSTRUCTION

    pg(s) 13-15

    This paper presents a method of vehicle-pedestrian accident reconstruction in case of vehicle low beam illumination and transverse movement of the pedestrian. This method allows to determine the pedestrian visibility time and pedestrian visibility distance in the case of nighttime accidents. The analysis of this type of accident is only possible if a certain shape and size of the illuminated area. This method can be very useful in the pedestrian accident reconstruction expert practice.

  • THE EFFECT OF THE ACCELERATOR POSITION ON THE FUEL CONSUMPTION OF ROAD VEHICLES

    pg(s) 16-18

    The fuel consumption of road vehicles is influenced by many factors. One of them is the acclerator position. Measurment of the fue lconsumption on a rollingstand was done for the quantification of this effect. The tested vehicle was Kia Cee´d with a petrol engine. The measurments were done in laboratory condiditons to give higher accuracy. The results describe the degree of the effect of the accelerator position. They can be used for the determination the position considering to the actual output power of the engine and for the detrmination of the correctly driver behavour. The correctly usage of the accelerator contributes to the reduction of environmental burden of transport.

  • POSSIBILITIES OF MEASURING THE BRAKE SPECIFIC FUEL CONSUMPTION IN ROAD VEHICLE OPERATION

    pg(s) 19-21

    Fuel consumption is one of the most important operating characteristics of road vehicles. In operation of road vehicles there we usually express fuel consumption in l/100 km for driving performance, or l/h when the car engine is idling. The fuel consumption can be quantified by several methods, and it affects a number of factors (driver, vehicle, and environment). It can be considered as a posteriori consumption, i.e. operational consumption. The priori fuel consumption (inserted, pre-defined) based on the construction properties of respective engine. Most often it is the priori fuel consumption expressed by measuring the effective consumption, which defines the amount of fuel consumed per unit of effort and time. It is usually quantified at a time when the engine is mounted to the vehicle itself. The contribution presents a practical example of measuring the effective fuel consumption in operation of road vehicles.

  • The role of traffic signalization on reduction of accidents on the Croatian roads

    pg(s) 22-25

    Safety of all road users on the roads is one of the fundamental social objectives. Measures for improvement or remediation of dangerous sites (black spots) in Croatia are carried out in several phases, from planning the envisaged measures, valuation measures, the implementation of measures to observation and assessment derived measures. Certain dangerous places are repaired only by changing traffic signalization and those sites and measures are described in this paper. In last eight years on the roads in Croatia, 215 dangerous places were repaired and partial restoration was carried on the 46 dangerous places. The success of provided measures, expressed through an analysis of the number and consequences of accidents on dangerous places for three years before and three years after restoration, shows the drastic reduction in traffic accidents on this places. The conclusions and solutions of these measures are presented in this paper.

  • INCREASE OF ELEMENTS LIFE BY MEANS OF PLASMA ELECTROLYTIC OXIDATION

    pg(s) 26-28

    Micro arc oxidation (МAО) is one of the advanced methods of obtaining thin-layer oxide ceramic coatings on the elements of machines of different functionality, allowing considerably increasing their life. The work is devoted to investigation of wear resistance and microhardness of coatings formed by micro arc oxidation on aluminium alloys in different electrolyte types. МAО is recommended for application at different engineering and maintenance technical enterprises, that produce, restore and harden elements.

  • LIFE SPAN AND RECYCLING OF MOTOR VEHICLES

    pg(s) 29-32

    The car is prevalently considered as a technical system that produces costs and pollution, also as a source of exhausted parts and recycled raw material. In the course of entire life cycle it seriously deteriorates natural balance to the extent to appear as a threat to overall ecological biodiversity on the Earth. Due to mass production and use what includes building-in vast number of materials and component that yield adverse effects on human health, engine cars has become one of major problems of today.
    The management of secondary waste requires an established flow of integrated information as well as an complementary system of knowledge and methods regarding landfill remnants reduction and adequate treatment of useful materials. Global automotive industry incites development of national economies and integrates contemporary achievements in the areas of techniques, technology and other scientific disciplines. Thus, the aspects of energy efficiency, waste recycling and environment protection sustainable development environmental shall be taken into account in car designing and production.

  • STUDY AND COMPARATIVE ANALYSIS OF THE MODELS FOR TRAFFIC SAFETY PREDICTION

    pg(s) 33-36

    The need of development and implementation of effective measures to increase the level of traffic safety is of utmost importance when it comes to road transport. Numerous studies on factors affecting road safety are the core of transport approaches and models made to reduce the occurrence of accidents. The purpose of this article is to make a comprehensive study of the models for analysis of the traffic conditions and their impact on traffic safety and to define the fundamental ones for implementation in Bulgarian conditions.

  • Analysis of hazards of sea environment from West Pomeranian sea fishing fleet

    pg(s) 37-39

    The paper presents analysis of hazards of sea environmental pollution by lubricating and hydraulic oils based on the west Pomeranian Sea fishing fleet. The analysis of hazards of environmental pollution has been presented here while on lubricating and hydraulic oils are used. The purpose of the Paper is to provide additional controls mitigate potential hazards.

  • POSSIBILITIES FOR OPTIMIZING MAINTENANCE OF MILITARY VEHICLES ON THE RESULTS OF TRIBOLOGICAL DIAGNOSTICS

    pg(s) 40-42

    Tribological diagnostics is a non-destructive and non-disassembling diagnostic method, that uses lubricating oil as a source of information about processes and changes in mechanical systems, to which it is applied. The paper deals with the mathematical processing, monitoring and analysis of the oil field data obtained from the atomic emission spectrometry in frame of the tribodiagnostic oil tests. The mathematical methods based on a regression analysis and calculations are used in the paper for oil data analysis. The whole assessment procedure and their outcomes serve as identification of a suitable approximation trend. With the same result we are capable of determining in-service operation history as well as giving inputs to maintenance optimisation. Nowadays the system requirements are set up and evaluated in various manners. We would like to keep both preventive and corrective maintenance costs as low as possible. A system design and a maintenance system help to fulfil this task. We propose to use one of the approximations presented in order to track the system operation behaviour.