Volume 22, No. 2 (2016)
Articles
COMPARATIVE ASSESSMENT OF ROAD RATING SYSTEMS
OLUFIKAYO ADERINLEWO(1)
In this study, three road rating systems were assessed and compared after carefully applying them to five major road case studies. The essence of these rating systems is to provide a consistent, reasonably objective and systematic approach for establishing priorities and scheduling and budgeting roadway rehabilitation requirements. The effectiveness of these systems was measured during the road condition survey and compared with one another. The most effective system out of the three was determined based on the different types and severity levels of pavement distresses identified for the five different routes.
TEORETHICAL EVALUATION OF ANTHROPOGENIC RISKS IN TAZLAU RIVER BASIN
LUMINITA BIBIRE(1), MIHAELA-BEATRICE BARBIERU(2), NARCIS BARSAN(1), ADRIAN STELIAN GHENADI(1)
In the Tazlau Basin there was a really strong anthropogenic impact. Many areas have almost totally been deforested, the grazing and agriculture have extensively and irrational been practiced, underground reserves have been exploited, too etc. The expanding of settlements along the rivers and building of modern communication routes along beds favored the phenomena of flooding and destruction of hydraulic works. These all aspects led to frequent occurrence of risk events: erosions, landslides, degradation of the rivers beds, pollution of air, water, vegetation, soil, etc. The paper identifies anthropogenic risk factors from Tazlau Basin, and proposes analyzes of the consequences and the measures to avoid these ensuing consequences.
CONCEPTUAL MODEL FOR ENERGY-EFFICIENCY MANAGEMENT IN STEAM-POWER PLANTS
OGNYAN DINOLOV(1)
An aggregate algorithmized conceptual model for controlling the energy efficiency in the steam-power plants, with taking into account the deviations in the qualitative characteristics of the used fuel, is proposed and justified. The model is applied for a coal-fired power plant, at two of its stages, through simulations in MATLAB Simulink and analyzing some of the data with the program Statistica. The development creates preconditions to algorithmize (to model) comprehensive energy efficiency measures in the operating plants, and to design and build new systems for monitoring and controlling the auxiliary electric power demand.
INFLUENCE OF ACOUSTIC FREQUENCY ON BEAN GERMINATION AND GROWTH PROCESS
ALISA MOȘNEAGA(1), VALENTIN NEDEFF(2), PETRU LOZOVANU(1)
In this work, research findings on processing bean seeds with sound waves in the range 0-9 kHz are presented. The process of germination has been examined for seeds soaked in heat treated water and plain water. In the initial stage, the conditions necessary to stimulate plant growth were created. The paper describes the experimental setup and the sound wave seed treatment procedure. The characteristics of the seed germination process were determined and compared with those of the control sample germination.
DETERMINATION OF THE REAL VALUES OF KINEMATIC INDEX CORRESPONDING TO THE MECHANICAL SEPARATION PROCESS
EMILIAN MOȘNEGUȚU(1), VALENTIN NEDEFF(1), MIRELA PANAINTE-LEHĂDUȘ(1), NARCIS BÂRSAN(1), DANA CHIȚIMUȘ(1), DRAGOȘ RUSU(1)
This article presents the methodology for determining the real values of kinematic indices which characterizes the mechanical separation of a mixture of solid particles. Mechanical separation of a mixture of solid-solid on surface provided with holes is the most common method of separation. To optimize equipment that performs this operation, both theoretical and practical characteristics are determined. Kinematic indices are part of the theoretical characteristics, helping to identify behavior of solid particles on a surface flat swing. Starting from an experimental batch, real values of the kinematic indices corresponding to up, down and sideways movement on the sieve were determined for the following types of real particles: grain, large grain beans, small grain beans and soybeans.
EVALUATION OF THE REVERBERATION TIME IMPROVEMENT IN A SPEAKING HALL
FLORIN MARIAN NEDEFF(1), MARCEL AGOP(2 3), EMILIAN FLORIN MOȘNEGUȚU(1), NARCIS BARSAN(1)
To improve a room's acoustic parameters there have been studied several variants of acoustic materials and devices that can be placed on the ceiling of the hall. The main objective of the study was the reverberation time measurement and calculation. By using the acoustic panel made from polystyrene, covered with jute on the both sides, has ensured the largest reverberation time decrease. Thus, we can say that the analyzed room can be used for speech activity (courses, conferences etc.)
COMPARATIVE ANALYSIS OF THE OWN EXPERIMENTAL TECHNIQUES OF PRODUCING THE FOAMED GLASS-CERAMIC
LUCIAN PĂUNESCU(1), MARIUS FLORIN DRĂGOESCU(1), SORIN MIRCEA AXINTE(1 2)
The paper presents experimental results obtained by a team of researchers from the company Daily Sourcing & Research SRL Bucharest in the field of producing the foamed glass-ceramic from waste bottle glass, coal ash and silicon carbide as foaming agent. The originality of the experiments consists in the use of electricity or microwave energy, unlike all techniques known worldwide consumers of fossil fuel. The product, obtained with low energy consumptions and very low pollutants emissions, has physical and mechanical characteristics of an insulating material, i.e. high porosity, low thermal conductivity and an adequate compressive strength.
A MULTICRITERIA DESCRIPTION OF RULES FOR PUBLIC PROCUREMENT
MALIŠA ŽIŽOVIĆ(1 2), MILUTIN ŽIVKOVIĆ(3)
At an announced tender of a contracting party, in the processes of public procurement of goods or services, a method of decision-making follows after interested bidders submit bids. Such method of choice is characteristic for all business systems with majority share of state capital. Methods of decision-making come down to selecting the best bids, because mistakes in the selection should be excluded. However, in practice, the problems of a wrong choice are manifested in dissatisfaction of the bidders. The problem then causes a delay in the procurement process, and often the retrial. In order to prevent this from happening authors of this paper suggest a somewhat different methodologies in selecting the most advantageous tender to the contracting authorities. The proposed method will be the case of the of Parking service (PC) from Belgrade (service of overhaul of the devices) will show a possible way of selecting the best alternative bids, taking into account previously adopted criteria.
INFLUENTIAL PARAMETERS DURING PRESSURE RELIEF EXPOSED IN WORKING CHAMBER OF HYDRAULIC CYLINDER PRESS
MILUTIN ŽIVKOVIĆ(1)
Relieving volumes, which were under pressure, with all the controls on the distribution and management of oil supply, may lead to the occurrence of the hydraulic impact, which is especially distinct in hydraulic presses. For these reasons, high speed unloading compression volume is the main cause of this phenomenon. This paper provide practical guidance for the design and calculation of important design parameters usually embedded devices - hydraulic command check valves (HCCV) (nominal size, pressure and decompression time) and the possibility of determining performance requirements using, from literature, the expressions and the nomograms.
THEORETICAL ANALYSIS OF INFLUENTIAL PARAMETERS TO COMPRESSION AND DECOMPRESSION PROCESS OF COMPRESSED OIL IN HYDRAULIC SYSTEMS OF THE PRESS
MILUTIN ŽIVKOVIĆ(1)
Compressibility of hydraulic oil is very significant for large diameter cylinder presses, especially if they are exposed to high pressures. The paper presents a theoretical analysis of the process of compression and decompression of oil in the cylinders with and without the presence of air presenting an analog model. Although considerations are relating to the ideal conditions of the process of compaction, the paper defines the basic mathematical processes depending on compression and discharge of the same. They refer to the definition of the time discharge and elimination of adverse effects in the same.