Volume 21, No. 1 (2015)
Articles
NUMERICAL SIMULATION FOR A MODEL OF BIOREMEDIATION WITH CHEMOTAXIS
ELENA-ROXANA ARDELEANU(1)
The aim of this paper is to present some numerical simulations for different values of parameters and to compare their influence for a reaction-diffusion model which describes chemotaxis phenomena in a bioremediation process of a polluted environment (soil or water). We set a model of Keller-Segel type, and we consider for this model a small influence of the degradation rate of pollutant ( ) and its diffusion coefficient ( ). For the numerical simulations, we used the package COMSOL Multiphysics v3.5a, working with the finite element method.
CALCULATION OF LOCAL STRESS STATE FOR SHELLS INTERSECTION
ANGELA CHELU(1)
This paper presents current calculation methods in order to determine the state of stress in the nozzle – shell junction section, their peculiarities, and limitations. These can be applied only to the linear-elastic behavior of the materials components. In the case of nonlinear behavior, beyond the yield stress limit, there is proposed a calculation method based on the concept of specific energy participation.
RISK MANAGEMENT METHODOLOGY OF INVESTMENT PROJECTS WITH ENVIRONMENTAL IMPACT
ELENA GINDU(1), AUREL CHIRAN(1), BENEDICTA DROBOTĂ(1), ANDY-FELIX JITĂREANU(1)
In projects, a strategic component is to identify all risks that might influence their success, prevent and manage them effectively. Risk management is essential to add value to an investment and improve results. With the economic and financial crisis in recent years, increasingly, more companies have realized the importance of using a system of risk management, given the multitude of variables that can influence the success of a project. These include: legislative changes, global political and economic instability, natural disasters, climate change, human resources, liquidity risk, environmental impact, risk of erroneous calculation of total project costs, risk of failure into initial project schedule, prolongation risk, the risk of failure of internal rate of return (IRR) and net present value (NPV) etc. The study proposes a new method of risk assessment and management in the investments projects with environmental impact and its application in a case study. The method will take into consideration besides the economic and financial indicators, hard to be understood by smaller investors, a set of simple and important questions that they have to analyze before deciding to start an investment project. The new methodology will have a comprehensive approach from identifying the investment opportunity, writing investment project until its implementation. This will take into account macroeconomic variables and the microeconomic environment that can influence the success of project implementation. The main advantage of applying the new methodology are: knowing all the variables that influence the success of a project realization; awareness of the importance of applying an effective risks management related to investment projects with environmental impact, increasing the quality and success of projects.
FLUVIAL LANDFORMS SEEN AS CAUSES OF THE DANUBE FLOODS CASE STUDY: OLTENITA - CALARASI SECTOR
ŞTEFANIA GRIGORIE (OMRANI)(1), FLORINA GRECU(1)
The aim of this paper is to analyze the fluvial landforms and to identify the main factors that influence the Danube floods. In this respect, we have performed a short analysis of the morphological and morphometric elements of the Danube Floodplain from the Oltenita - Calarasi area, of the wetlands and a correlation between these and the floods that have been cause. Finally, the current situation of embankments was assessed. For understanding the causes of floods in the studied area, two aspects should be taken into consideration: the morphometric and morphologic properties of the floodplain (low altitudes, low slope, low roughness) and human intervention (drainage of the lakes and wetlands, harnessing measures like irrigation and drainage channels, lack of embankments rehabilitation).
ASPECTS REGARDING THE KINSHASA URBAN LANDFILLS ASSESSMENT AND PROPOSALS FOR SUSTAINABLE DEVELOPMENT
HOLY HOLENU MANGENDA(1), VALENTIN NEDEFF(2), NARCIS BARSAN(2), EMILIAN FLORIN MOȘNEGUȚU(2), DANA CHITIMUS(2), DRAGOS RUSU(2)
Landfill management is one of the major issues in the application of sustainable development principles and ecological maintenance of the cities. Promoting their appreciation, and even more preventing for their minimization, are at the heart of many debates within the scientific community, local communities, companies and civil society. The city of Kinshasa is demographically growing much too fast, its capacity to manage the waste produced by 10000000 inhabitants is more than overwhelmed. The question is “WHAT CAN BE DONE?” Today it is acknowledged that these quantities of waste can be fruitfully put to use rather than looking at it simply like at a bothersome, congesting and polluting phenomenon. We have now to consider this above all a “secondary” raw materials resource. The problem is not the amount of waste, but the inability of governments and waste disposal companies to get rid of it. The city of Kinshasa seems today to have a certain disconnection from its environment because of the impacts of human actions these last fifty years. In addition to household refuse and pollution causing an unsanitary environment in most parts of the city, one particularly notes the consequences of uncontrolled urbanization and poor waste management, resulting in widespread insalubrity of the city. The present paper was assessed the situation regarding the urban landfills in Kinshasa by using field evaluation and population questioning.
SIGNIFICANCE OF BUILDING MAINTENANCE MANAGEMENT SYSTEM TOWARDS SUSTAINABLE DEVELOPMENT: A REVIEW
MD AZREE OTHUMAN MYDIN(1)
The notion of building maintenance is separated into two elements specifically building maintenance management and building maintenance technology. Building maintenance management should accurately be considered as unfolding how a system of maintenance endeavor might be prearranged to deal with a problem of building maintenance. It distinguishes that, aside from locating and remedying the building deficiency an effective programme to restrain overall cost of maintenance but also in an effort to maximize the gain and benefits of the savings. There are a few factors that influence the decision to accomplish the maintenance work. There are the maintenance needs that is the principal aspire of maintenance is to protect a building in its early stage and some major rationale for maintaining building are retaining its significance and value of investments, maintaining the building in a condition that it persists to accomplish its purpose and presenting a good outer shell. Besides that, the efficient maintenance management system embraces many skills and efforts that include identifying maintenance needs and the accurate and spot on remedies. In general, there have four types of maintenance which are breakdown or corrective maintenance, scheduled maintenance, preventive maintenance and also predictive maintenance. This paper will review and discuss some of the major elements of building maintenance towards achieving sustainable building.
CALCULATION OF SOME THERMODYNAMIC PROPERTIES OF WATER FOR THE BOUNDARY POINTS BETWEEN REGIONS 3 AND 4 OF INDUSTRIAL FORMULATION IAPWS-IF97
ALIREZA POURSHAGHAGHY(1)
In the calculations relating to the thermodynamic cycle of steam power plants, the enthalpy and the entropy of saturated liquid and saturated steam (hf, hg, sf, and sg) are needed. If one uses industrial formulation IAPWS-IF97, these four parameters (hf, hg, sf, and sg ) should be determined by cumbersome numerical computations when the saturated pressure has a value between 16.529 MPa and 22.064 MPa. In this work, easy programmable equations are provided to calculate hf, hg, sf, and sg in this range of saturated pressure.
EXPERIMENTAL ANALYSIS OF THE INFLUENCE OF FEED RATE ON QUALITY OF CUTS PERFORMED BY AWJ
CRINA RADU(1), EUGEN HERGHELEGIU(1), CAROL SCHNAKOVSZKY(1), CATALIN TAMPU(1)
Abrasive waterjet (AWJ) cutting technology is one of the most recent developed non-traditional processes used in industry for the processing of difficult-to-cut materials which usually lead to a pronounced wear of conventional tools and generation of damaged surfaces. The efficiency and the quality of AWJ depend on many parameters, some of them precisely controllable (e.g. water jet pressure, feed rate) while others uncontrollable (e.g. focusing tube size, waterjet orifice size). The aim of current study was to analyze the influence of feed rate at low working pressures on the quality of cuts, quantified by the parameters specified in the ISO/WD/TC44 N 1770 standard.
STUDY REGARDING THE IDENTIFICATION OF THE WATER POLLUTION SOURCES AND FACTORS ON THE SIRET RIVER IN THE BACAU-MARASESTI SPAN
MĂDĂLIN-IONUŢ ROTARU(1), VALENTIN NEDEFF(1), ALEXANDRA-DANA CHIŢIMUŞ(1), EMILIAN FLORIN MOŞNEGUŢU(1), NARCIS BÂRSAN(1)
The main pollution sources of the Siret river and its tributaries in the Bacau-Marasesti span are submitted in the present study. The Siret River, through the watershed it forms, is one of the largest tributaries of the Danube. Thereby Siret river through its water volume outlet for the Danube River, which crosses our country, is considered a major pollution agent for the surrounding areas of the river from a social, economical and agricultural point of view.
THE IMPACT OF MANGALIA HARBOUR’S BREAKWATERS ON THE SHORE AND CLIFF IN “2 MAI-VAMA VECHE” COASTAL AREA
GELMAMBET SUNAI(1)
The paperwork is part of a substantiation study about the current state of the NW Black Sea coastal area and it consists in the establishment of a reference database regarding hydrotechnical structures, the existing coastal protections, their impact and the identification of risk areas. A high-risk area is “2 Mai - Vama Veche” region, located in The Southern Romanian Coastline, due to the sharp beach erosion and the cliffs instability that endanger nearby buildings. The coastal protections, the offshore breakwaters, the industry development in the coastal region and the construction of storage lakes and dams in the river basins have influenced the conditions in which The Romanian Coast is found nowadays.
THE EFFECT OF WATER HARDNESS ON RHEOLOGICAL BEHAVIOR OF DOUGH
ELENA-MĂDĂLINA ȘTEFAN(1), GHEORGHE VOICU(1), GABRIEL-ALEXANDRU CONSTANTIN(1), MARIANA FERDEȘ(1), GHEORGHE MUSCALU(1)
Flour and water are basic components in dough formation process. The water quality affects the whole breadmaking process and the quality and retention period of bakery products. In bakery, an important role is played by the hardness of water; are preferred water having a hardness by 5 - 10o D (German degrees) and, in some cases, are preferred the waters with 10 – 20o D, depending on the characteristics of gluten. For the experimental determination, presented in this paper, were used samples of FA 650 flour type (white flour) and four kinds of water with different hardness values. To determine the dough rheological characteristics were made measurements according to AACC 54-21 standard method, using the Brabender Farinograph-E model (300 g mixer capacity). The paper presents the study of rheological characteristics variation of wheat flour dough, depending on the water hardness used in mixing and formation process.