Journal of Engineering & Processing Management (EPM)
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Causes of increased concentration of fluorides in groundwater in Srebrenica municipality
Full text linkGroundwater, as the mainresource of drinking water in the Republic of Srpska, is sometimes neglected regarding quality monitoring. It is especiallya characteristic of rural water supply sources as autonomous waterworks, individual intakes and wells. For the first time comprehensive analyses of the groundwater quality in rural areas of Srebrenica municipality have been provided in 2010. The results are more than interesting. Beside some standard problems in physic-chemical properties like increased turbidity, iron and manganese, there was emerged problem of increased fluoride concentration in more than one third samples of groundwater. The study of fluoride concentration, given in this paper, includes the causes of this phenomena and possible health impacts. It defines geological setting, or precisely mineralogical properties of the rocks and their interaction with groundwater, as a key factor of the problem. Further, analyses include recommendations regarding future exploration areas with probably same effect of the geological setting on groundwater quality in the territory of the Republic of Srpska. It is very important because the problems related to the long-term consumption of groundwater with fluoride concentration above 1.2 mg/L could be a trigger for very serious diseases like dental and skeletal fluorosis, diseases of pineal gland, kidneys, urinary bladder, thyroid gland, gastro-intestinal tract etc
Managing of the production performance
No full textToday, most companies face numerous problems that are the result of events in a modern business environment. Failure in business can lead to disappointment with both managers and other employees. This paper presents a conceptual framework for enterprise resource management. From the prerequisites of production through the engagement of production factors to the minimization of costs, this paper aims is to illustrate how and with which contribution the production performance is properly managed
Air-thermal oxidation of zirconium
Full text linkZirconium is one of those few metals which are capable of dissolving relatively large quantities of oxygen. When heated in air at elevated temperatures, an oxide layer is built up at the metal surface. The oxidation of mechanically polished zirconium was studied in the range 500-900oC in air atmosphere, at temperature intervals of 100oC, for exposure times from 5 min to 1860 min for each temperature. The weight gain of the oxidized species was the reacted amount of oxygen with zirconium for the formation of the ZrO2. The weight gain and thickness of the oxide film increase with the increasing of the oxidation time and temperature. The oxidation initially followed a parabolic rate at all temperatures. At temperatures higher than 700oC oxide “breakaway” appears at the longest oxidation times. Microstructural investigations have shown that the oxide layers are compact and with good adhesion to the metal surface, but at temperatures over 700oC, radial micro-cracks appear. Raman spectra of the formed oxides at the investigated temperatures are characteristic for monoclinic phase
Co-crystal explosives-explosives improved characteristics
No full textExplosive substances are very important compounds from the point of manufacture, storage, transport and use. Research and development of secondary explosives in the previous time is intensified in order to obtain improved explosive materials is physical, chemical and explosive characteristics. One of the directions of development are research in the field of co-crystals. In this paper, present the literature results of previous studies of co-crystals of modern conventional explosives. The co-crystal of the compound represented CL-20, octogen (HMX), TKX-50, trotyl (TNT) and certain compounds of explosive to be used to a minor extent. Analysis of test results of crystal structure, intermolecular interactions, mechanical sensitivity, thermal decomposition, reaction mechanisms creation products and explosion characteristics indicate improved explosives properties in relationship to components that make it
Corrosion stability of electrochemically deposited Zn-Mn coatings
No full textThe topic of this paper is testing corrosion stability of electrodeposited Zn-Mn coatings by using electrochemical impedance spectroscopy (SEI). The coatings were deposited galvanostatically on a 3x3 cm steel. 99.99% pure zinc was used as the anode. The electrodeposition was carried out from four chloride solutions. Solution 1 was without manganese (3mol/dm3 KCl, 0,42mol/dm3 H3BO3, 0,45mol/dm3 ZnCl ), solutions 2-4 had the same concentration of KCl, H3BO3 and ZnCl2 as in solution 1 and only MnCl2·4H2O was added in various concentrations. Final concentrations of solutions 2-4 were as follows: solution 2 - [Mn2+]:[Zn2+]=1:1 (0,45mol/dm3 MnCl2·4H2O); solution 3-[Mn2+]:[Zn2+]=1:2 (0,225mol/dm3 MnCl2·4H2O,); solution 4-[Mn2+]:[Zn2+]=2:1 (0,9mol/dm3 MnCl2·4H2O). Zn-Mn coatings were electrodeposited on chemically prepared samples of steel (cathodes) for 15 minutes from all solutions at current densities of 1 А/dm2 , 2 А/dm2 and 4 А/dm2 . The obtained results showed that the Zn-Mn coatings deposited at all current densities have a higher corrosion stability compared to the pure zinc coating. For examle, of all the coatings deposited at the current density of 1A/dm2 the coating deposited from solution 2 had the greatest corrosion stability, whereas the coatings from solutions 3 and 4 were more corrosion resistant at the current density of 2 and 4A/dm2 . Corrosion resistances, determined from the Nyquist diagrams (Zimag) of the pure Zn coatings, were in the range of 80-130 Ω, depending on the deposition current density, while the resistances of the alloy coatings were around 150-200 Ω. Based on results obtained by electrochemical impedance spectroscopy it can be concluded that the most resistant Zn-Mn coatings were deposited from the solution 3 ([Mn2+]:[Zn2+]=1:2), at the current densities of 2 A/dm2 and 4 A/dm2
Validation of method for cannabis identification using gas chromatography technique
No full textThe methods of analysis in forensic must be reliable in order for the results of the analysis to be accepted as evidence in court proceedings. The reliability of methods is checked through the validation process, which should be performed before introducing a method into the routine practice of the laboratory. This paper describes the procedure for identification of Cannabis sativa L. plant and its preparations (resin - "hašiš", oil) using a gas chromatography technique with a flame ionization detector, as well as the validation procedure of the method by which identify three basic cannabinoids: psychoactive tetrahydrocannabinol, cannabidiol and cannabinol. The method validation process includes the necessary equipment, the description of the required performance of the analytical method, the conducting of the tests, the way and the criteria for evaluation validation results
The possibility of application of xanthan in removal of metal ions from wastewaters
No full textBiopolymers have the ability to absorb large amounts of water or biological fluids. They are swelling and forming hydrogels. Thanks to this, they have found a variety of applications, and among others they can be used to remove some metal ions from the water. Due to its unique structure and exceptional rheological characteristics, microbiological biopolymer, xanthan, can also be used for purification of wastewater because structures formed in the presence of metals can be easily separated.Therefore, the research from this paper was carried out in order to examine the possibilities of crosslinking the xanthan with different metal ions. Based on the successful crosslinking and stability of the formed crosslinked structures, it has been estimated that with the use of this biopolymer it is possible to remove ions of lead and iron from wastewaters
Analysis of organic pollutants in water samples of White Drin, Black Drin and Fierza Reservoir
Full text linkThis study presented data about concentrations of some organic pollutants in Albanian part of Black Drin (BD), White Drin (WD) and Fierza Reservoir (FR). Thirteen stations were analyzed in this study. Sampling of water was realized in May 2017. Drin River presents important aquatic area in Albania. For all water samples were analyzed organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), benzene, toluene, ethylbenzene and o-, m-, p-xylenes (BTEX) and polyromantic hydrocarbons (PAH). Organochlorined pesticides and PCBs were found in higher level for Fierza Reservoir stations. Their concentrations for Black and White Drin samples were 5-10 times lower
Studying of lipophilicity of potential biological active cyanoacetamide derivatives
No full textBy applying the Lipinski’s rule for selected cyanoacetamide derivatives the possible existence of biological activity is theoretically investigated. Alos,using appropriate software packages and applying reverse-phase thin-layer chromatography (RP TLC18 F254s) in water-t-butanol, water-dimethylformamide and water-dimethylsulfoxide the lipophilicity of the studied cyanoacetamides was determined. Chromatographic retention parameters, RM0 and m, as presumed criteria of lipophilicity of examined cyanoacetamides were correlated by linear regression analysis with standard measure of lipophilicity, log P, with important pharmacokinetic predictors and selected parameters of toxicity. The established linear dependences are described by high regression coefficient values, r, which showed that RP TLC18 F254s allows reliable determination of the lipophilicity of cyanoacetamides as potentially bioactive compounds
Compatibility of slideway oils with water soluble metal working fluids
No full textSlideway oils have application in many industries, such as automotive, food, beverage, packaging, and considerable amount is used in small machinery workshops. Market analyses have shown that most common viscosity grade is ISO VG 68, followed by ISO VG 220. Because water soluble metal working fluids come in contact with slideway oils, purpose of this research was to test the influence of water soluble fluids on most commonly used viscocity grades of slideway oils. Compatibility of slideway oils with water soluble metal working fluids is very important for effective funcioning of slideway machines, and for life span of slideway oil itself. Compatibility was tested with specially adjusted demulsivity tests, regarding the capability of separating specific amount of water soluble metal working flud from slideway oil. Different formulations of cooling and lubricating fluid and slideway oil give different times and ratios of separated oil and water on modified test. Test results can be used in development of new formulations of these products, and with selection of emulsifying fluids for metal working and oils for slideways for some applications