Volume 22, No. 3 (2016)
Articles
NUMERICAL ANALYSIS OF EFFECTS OF HYDRAULIC GRADIENT ON MASS FLUX OF SALTWATER INTRUSION IN COASTAL AQUIFERS
JAMES A. ADEGOKE(1), OLATUNDE I. POPOOLA(1), OLUDOTUN O. FALUY(1,2*)
Coastal aquifers are distinguished from other aquifers because of saltwater intrusion effects, which cause contamination of groundwater in coastal regions. This study addressed the significance of hydraulic gradient and porosity of the coastal aquifers on contaminant transport of saltwater. Results showed hydraulic gradient of the aquifer has significant impact on the contaminant transport in coastal aquifer. When the hydraulic gradient between freshwater and saltwater is high and directed toward the sea, diffused rate of saltwater into the groundwater would be low. Therefore, hydraulic head of freshwater in coastal aquifer must be maintained at high level to control saltwater intrusion.
DIOXINS / FURANS (PCDDs/PCDFs) CONTROL IN CEMENT INDUSTRY IN ROMANIA
CRISTIAN CIOBANU(1), GHEORGHE VOICU(2*), MAGDALENA-LAURA TOMA(2) SILVIU MARCU(1)
The most important sources of dioxins are waste incineration, industrial (dioxins are by-products), volcanic eruptions, fire, etc. The Romanian law 278/2013 provides the air emissions limit of 0.1 ng/Nm3 gases for dioxins and furans emitted by the incineration and co-incineration plants. Some aspects regarding the control of these substances in the gases from a cement factory in Romania are presented in this paper. In incineration plant were used various fuels. However, the substances level mentioned above was within the allowed limits.
MODEL FOR ENERGY-EFFICIENCY AUDIT AND MONITORING OF THE COAL PROCESSING SYSTEMS IN THE FOSSIL-FUEL POWER PLANTS
OGNYAN DINOLOV(1*)
Based on interpretation of existing developments, an aggregate model for energy audit and monitoring of the electric-energy efficiency in the coal processing systems in the fossil-fuel power plants is developed. The model takes into account the nominal power capacities of the available drives, by which the usability of the installed power capacity is considered and the interdependence between the power consumed and the relative consumption is avoided in determining the aggregate relative electric-power consumption. The model is justified by conducting an energy audit of a typical coal processing systems in operation. The results of this research can be a basis for the development of models of systems and systems for qualitatively new monitoring of the overall electric-energy efficiency in the fossil-fuel power plants.
ENVIRONMENTAL IMPACT OF WATER TREATMENT PROCESS. A SYSTEMATIC REVIEW OF EVALUATION METHOD
FLORINA FABIAN(1*), VALENTIN NEDEFF(1), MIRELA PANAINTE - LEHADUS(1), NARCIS BÂRSAN(1), OANA IRIMIA(1), SILVIA RACOVITA(2)
In an international context in continuous development, water treatment processes become an important component of society where we live. Attention is directed on water treatment processes in the context of increasing water demand. This study proposes a systematic review of methods for the assessment of the environmental impact of Water Treatment process. The approach is based on the evaluation of LCA, Externalities Evaluation methodology and Carbon Footprint methodology, each of these methods have the environmental indicators able to relate direct and indirect emissions generated by any water treatment process. The present review compares and discusses the implementation of the above-cited methodologies to different case studies. The results in short show that Carbon Footprint only assesses the global warming potential of a water treatment plant, whereas Life Cycle Analysis and assess multiple environmental impact categories, which may include global warming, but also impacts on human health, ecosystems quality, etc. There are different standards and organizations around each assessment. The ExternE method on the contrary aims to quantify external impacts, from both economic and social points of view, to weight each endpoint of the impact categories.
RESEARCH ON SINGLE-LEAF WALLS MADE WITH LIGHTENED CLAY BRICKS
MANUEL C. JUÁREZ (1*), Mª PILAR MORALES (2,3), PEDRO MUÑOZ(4), PABLO OLASOLO(1)
This paper explains the studies conducted on the subject by RADEB (Research and Development in Energy and Buildings) Research Group at the University of La Rioja. The aim of this work is to study the possibility of improving the thermal transmittance of a single-leaf wall made with lightened clay bricks. A first aspect is to study the possibility of lightening the clay by using additives, reducing the clay’s conductivity without decreasing its resistive ability. The internal and external geometry of the bricks has been studied by the Finite Element Method (FEM). Different wall assemblies with these bricks have been studied.
NONLINEAR PROPERTIES OF BARIUM TITANATE CERAMICS
IVAYLO LAZAROV (1*), ANKA ZHEGLOVA(1)
The materials based on barium titanate have nonlinear dependence of polarization on the intensity of the electrical field. The properties of those materials are used when different automation elements such as primary converters, phase regulators for low and high frequencies, sensors, modulators etc. are derived. Ceramics based on barium titanate (BaTiO3) alloyed with H3BO3 and Bi2O3 have been derived and researched. The influence of the temperature of sintering on the values of the dielectric permittivity on the structural properties has been determined. The influence of the quantity of the added material on the temperature dependencies and the non-linear properties of the ceramics have been analyzed. Both legation additives decrease the sintering temperature. However, the values of the dielectric permittivity decrease while the non-linear properties of the doped barium titanate (BaTiO3) improve. The coefficient of non-linearity reaches its maximum for the H3BO3 composites, synthesized at temperature of 1100 oC.
PROPER TIME IN TECHNICAL SCIENCES AND ALTERNATIVE NOTIONS FOR THE FORCE, MECHANICAL WORK AND HEAT
ALEXEI MAFTULEAC(1*)
The notion of proper (localized) time is one of the more important in the theory of relativity and is often used to explain phenomena that occur in conditions of high speeds or gravitation. In this paper, on the basis of the concept of proper (localized) time we tried to explain the functioning of simple mechanisms as a change in their space/time relationships, and to consider from another point of view some notions of physics (mechanics). A hypothesis about space and time equivalence and their mutual compensating change in every phenomenon that occurs, has been proposed. This hypothesis is substantiated with formulas and data from literature. This article may be of interest to the physicists and engineers.
A SYSTEMATIC STUDY REGARDING THE IMPORTANCE OF OBTAINING ECOLABEL IN ROMANIA
ANTONINA TEMEA(1*), VALENTIN NEDEFF(1), CLAUDIO COMOGLIO(2), SERENA BOTTA(2), MIRELA PANAINTE-LEHADUS(1)
The purpose of this paper is to review and present a short synthesis of the scientific literature on Ecolabel and an analysis of the types of products and services in Romania that obtained this environmental label. European eco-label is the only environmental quality label (type I; ISO 14024), awarded at institutional level (EC) valid all around the Europe, and it represents a unique opportunity to satisfy consumer expectations. In this way is promotes the design, production and marketing of products with lower environmental impact during their entire life cycle compared to other products in the same category. The EU Ecolabel covers a wide range of product groups, from major areas of manufacturing to tourist accommodation services. Key experts, in consultation with main stakeholders, develop the criteria for each product group in order to decrease the main environmental impacts over the entire life cycle of the product. Because the life cycle of every product and service is different, the criteria are tailored to address the unique characteristics of each product type. The European Ecolabel was introduced in Romania in 2002.
A MODEL FOR DETERMINING THE SAFETY LEVEL OF OCCUPATIONAL WORK USING ACCIDENTS AND INJURIES MEASUREMENT PARAMETERS: A REVIEW
T.A. YUSUF (1*), O.M. SANUSI (2), H.O. ADEYEMI (3)
Frequency Rate (FRR), Fatality Rate (FAR) and Severity Rate (SR) are common parameters used in communicating the research output of occupational accidental injuries. These parameters have been used to provide a model for classifying an occupational work activity into five level/degrees of safety ranging between Very Safe and Highly Unsafe. With a work activity defined as x: x ≤ 0.01, x ≤ 0.003 or x ≤ 0.03 indicates Very Safe Level while x > 0.04, x > 0.015 or x>0.11 indicates Highly Unsafe Level according to FRR, SR and FAR respectively. A case study is provided from an existing work to experiment the application of the model.