Journal of Engineering & Processing Management (EPM)
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BIOMIMETIC METHOD OF CALCIUM HYDROXYAPATITE SYNTHESIS
Get PDFCalcium hydroxyapatite (CHA) has been synthesized biomimetically using simulated body fluid (SBF) alone and in combination with Fetal Calf Serum (FCS) and Eagle’s Minimum Essential Medium (EMEM). Chemical composition of the used SBF is like composition of human plasma, with small differencies in some ions concentrations, and pH value was adjusted to 7.4, that corresponds to pH of physiological media. As substrate for biomimetic deposition of apatite, thin films of silica, deposited on steel plates, were used. The analysis of phases obtained on the surface of SiO2 films after different periods of CHA nucleation, was done by FTIR-ATR method. SEM investigations pointed out the mechanism of nucleation, while combination of the method of measurement of film mass and BET method showed that thickness of nucleated CHA films depend on time of sample soaking in SBF
CONTEMPORARY PARADIGMS OF MANAGEMENT OF ORGANIZATIONAL SISTEMS
Get PDFUnlike the classical management approach based on hierarchical relations within an organization, a behaviorist concept of business systems management attracts more and more light. This refers to new paradigms of management such as organizational behavior, as well as the culture and climate of an organization. Organizational behavior targets individuals, as well as working groups, all the way to the business system as a whole, while organizational culture is observed through moral, social and behavioral norms of an organization, based upon beliefs, attitudes and priorities of its members. Organizations wishing to be not only more effective, but also a more pleasant working environment, have to do some research into the behavior of its members. That enables the prevention of conflicts and productive channeling of human endeavors. Understanding of human behavior is necessary for improving the functioning and bringing the wishes and needs of an organization and its members closer. These approaches are usually followed by the phenomenon of organizational climate, which refers to the hallmarks of workplace environment and represents the accepted model for establishing an agreeable atmosphere within the organizational structure given. This is the way to advance relations that are being established within an organizational system in order to increase its business activities efficacy and humanize the work as well. It is necessary to add the emotional intelligence of the leaders to the concepts previously mentioned as yet another modern paradigm of organizational systems management
A CURRICULUM ANALYSIS AND INTEGRATION OF CHEMICAL ENGINEERING EDUCATION
Get PDFMost commonly, all reforms of curriculum and study programmes in the educational system of Chemical Engineering are based on knowledge integration and developing tools which are designed to help students acquire a global picture of their professional calling. Therefore, this reform, which is the most comprehensive so far, and which was caused by the implementation of the Bologna model as well as by the small number of students at technical faculties, has a major significance for all the faculties of Chemical Engineering. This study, apart from presenting the factors which affect the development of studies in this area, gives a thorough review of the past and the existing educational systems at the faculties of Chemical Engineering in Europe. Thus the implementation of the Bologna model is used in order to harmonize curricula in the educational system of Chemical Engineering in Europe through defined goals of knowledge acquisition and a basic curriculum with the topics that should be incorporated in the curriculums of all the faculties of Chemical Engineering
A NEW PROCEDURE FOR OBTAINING CALCIUM SULPHATE α-HEMIHYDRATE ON THE BASIS OF WASTE PHOSPHOGYPSUM
Get PDFInvestigations, conducted in this study showed that waste phosphogypsum-dihydrate represents a burden which even must not be kept in deposits because of its large quantity in relation to the main product – phosphoric acid, as well as because of great impact of a phosphogypsum deposit on the environment. By the proposed procedure, calcium-sulphate dehydrate is transformed into a far purer α-hemihydrate which, with its physic-chemical characteristics, approaches natural gypsum and contains additional components which enable formation of small-grain phosphogypsum which may be utilised in construction industry. Test installation, given in this study, is highly automated and designed in such way to be operated by only one person. The obtained α-hemihydrate may be utilised for obtaining of gypsum blocks and dry hemihydrate
ELECTRODEPOSITION AND MORPHOLOGY OF COPPER POWDER PARTICLES OBTAINED AT DIFFERENT CURRENT REGIMES
Get PDFThe effect different deposition regimes (constant and reversing currents), on the powdered copper electrodeposits morphology were investigated. The morphology of electrodeposited copper powder was investigated using a scanning electron microscope (SEM). The effect of the current amplitude, cathodic to anodic time ratio and period of the current wave are discussed. It is shown that the parameters determining the reversing current wave determine the micro-morphology of the copper powder particles deposited
QUALITY ANALYSIS OF BASIC RESOURCES FROM THE ASPECT OF FEASIBLITY OF ALUMINA CEMENT PRODUCTION
Get PDFMain objective of this paper is feasibility of alumina cement production on the Republic of Srpska resources basis. As is known calcium-alumina cement is type of mineral hydraulic binder. As basic resources of CAC production are used bauxite and calcite. There are two main production processes: the fusion, Al2O3 less than 50% and the sintering process, Al2O3 higher than 50%. Republic of Srpska has two main bauxite deposits: Milici and Srebrenice mines and alumina factory in Zvornik. There are a couple calcite deposits with possible CAC technology requirements. Also the nearest CAC factory is in Istria, Republic of Croatia
ECOLOGICALLY ACCEPTABLE LUBRICANTS
Get PDFIncrease of ecological awareness affected the realization of more strict laws concerning the environment, which are being imposed in many countries. It also affected lubricant area and tendency for decreased pollution that lubricants can induce if they are uncontrollably spread around. Earlier it was believed that biodegradability is the most important criteria for evaluating the ecologically acceptable lubricants. Many studies had given the results of testing the affect that lubricants have on flora and fauna in water, their accumulation potential and human health. European Union commission had presented in 2005. the document under number 2005/360/EC that applies on lubricants that can carry the so-called Eco-label. It defines seven basic criteria that lubricants must fulfill. Manufacturers of components for lubricant production and lubricants itself had gotten newmissions. In this paper are shown the results of lubricant testing that completely satisfy the given criteria. They apply on toxicity for flora and fauna in water, bio accumulation potential and harmful health impact potential. Special demand is applied on using feedstock that are not only biodegradable, but are produced from renewable sources, and thus fulfill technical lubricant performances
METHODICAL APPROACH TO IDENTIFICATION AND QUANTIFICATION OF CORROSION DAMAGES OF CORROSION THE CASING STEEL TUBES IN PETROLEUM INDUSTRY
Get PDFMethodological approach of identification and quantification of corrosion damages of the steel tubes which use for casing the well in petroleum industry are presented in the paper. A description and consequence of steel corrosion of casing steel tubes with examples from experience were also analyzed. Initiate steps with the aim to prevent these phenomena are considered
MATHEMATICAL MODELLING FOR DRYING OF SAWDUST IN A TRIPLE PASS ROTARY DRYER
Get PDFToday, rotary dryers are often use to dry sawdust prior to their further processing, palletizing and briquetting, into commercially voluble product. This paper present mathematical model for drying process of sawdust particles in a triple pass rotary dryer. As basis for this model, we used existing mathematical models for drying of sawdust and other biological materials in a single pass rotary dryer, which are modified and extended in order to satisfy mathematical description of motion of material in the triple pass rotary dryer. Developed mathematical model is used as basis for further developing of the simulation model that predict temperature and moisture profile sawdust and drying along the dryer. In order to solve and validate developed rotary dryer model, commercial triple pass rotary dryer, installed in enterprise Panensa near town of Srbac, have been analysed, and measured sawdust drying data have been used for comparison. Comparison between predicted and the measured results were good. Mathematical model i.e. rotary dryer simulation model developed in this paper is going to enable better management and controlling of process in the mentioned commercial rotary dryer as well as in other rotary dryers for wood waste with modification of appropriate model parameters
STRUCTURAL CHARACTERISTICS OF ELECTRODEPOSITED COPPER COATINGS
Get PDFThe samples of rolled copper were mechanically and electrochemically polished in suitable electrolytes for electrochemical polishing. These substrate surfaces that had been prepared in advance, served as the basis for depositing of copper layers from two baths, namely, from the basic electrolyte(OR) with the following composition: 240 g/dm3 CuSO4 ∙ 5 H2O + 60 g/dm3 H2SO4i as well as from the bath which contained brightening addition agents(OR +DS). STM and AFM techniques show in great detail the structural properties which determine whether the metal surfaceis are as bright as a mirrior or not, that is, whether the obtained topography of the surface is more or less rough. It was determined that a considerable increase of roughness occurred in the samples where copper layers were deposited from the basic sulfate bath (OR) when compared with mechanical, and mechanical-electrochemical samples. In addition, depositing of the samples from the bath with brightening addition agents (OR +DS) resulted in the decrease of surface roughness