Journal of Engineering & Processing Management (EPM)
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DETERMINATION OF THE LEAD CONTENT IN SPINACH BY UTILIZATION OF THE POTENTIOMETRIC STRIPPING ANALYSIS (PSA)
Get PDFAbsorption of elements by plants is regulated with a series of factors that depend on the plant in issue and conditions of living environment. The main factor that controls the mineral content in plants is a genetic potential for sustenance with different minerals. It is being exhibited with unequal sensitivity and ability for accumulation of specific elements. Particularity of species and genotypes with regard the mineral sustenance originates from their adjustment to specific ecological conditions, particularity related to metabolism, morphological and anatomic structure. A plant’s ability to absorb microelements depends on morphology of its root, which has three major functions: connecting the plant to its surface, absorption and transport of substance and water, synthesis of phytohormones and other organic compounds. In addition to its role in inclusion of elements from the ground, the root doubles as a fairly good filter. Essential elements pass through the root barrier easily, straightforwardly advancing to the upper parts of a plant while still being mobile, whereas toxic elements are withheld, unless their presence is in ample concentrations. It is known that the root epidermis represents a barrier for lead absorption. Zinc has a distinctively large mobility through the plant and minor accretion in the root. While toxic and physiologically unnecessary for any plant, cadmium advances rapidly towards the upper parts. Since lead has the worst mobility towards the upper parts of the plant, taking into consideration its high toxicity levels if it becomes the food chain constituent, this report elaborates determination of the lead content in spinach leaves. This determination of the lead content was conducted by utilization of the Potentiometric Stripping Analysis (PSA).The Potentiometric Stripping Analysis (PSA) is an electroanalytic highly sensitive method for determining the content of many heavy metals. Examining of sensitivity threshold and linearity range was conducted prior to this measurement. 
SYNTHESIS AND STRUCTURAL ANALYSIS OF A Cu(II) COMPLEX WITH PYRIDOXAL S-METHYLISOTHIOSEMICARBAZONE (PLITSC) LIGAND
Get PDFReaction between a warm water mixture of pyridoxal hydrochloride (PL.HCl), and Smethyilisothiosemicarbazidehydroiodide (SMeTSC.HI) in the presence of Na2CO3 .10 H O, we got pyridoxal S-methylisothiosemicarbazone (PLITSC; H2L). Ligand with appropriate Cu salt is coordinated, to give next complex: dark-brown, penta coordinated, square-pyramidal structure, mono(ligand)complex Cu(II) formula, [Cu(PLITSC)Br(CH3OH)]Br.In this work is given synthesis and structure of the complex with Schiff-based ligand
FIBER REINFORCED CEMENT COMPOSITES-IMPROVEMENT OF MECHANICAL AND DEFORMATION PROPERTIES
Get PDFoai:ojs2.jepm2021.tfzv.ues.rs.ba:article/10This paper presents the results of authors' laboratory testing of the influence of steel fibers as fiber reinforcement on the change of properties of cement composite mortar and concrete type materials.Mixtures adopted - compositions of mortars had identical amounts of components: cement, sand and silica fume. The second type of mortar contained 60 kg/m3 of fiber reinforcement, as well as the addition of the latest generation of superplasticizer. Physical and mechanical properties of fiber reinforced mortars and etalon mixtures (density, flexural strength, compressive strength) were compared. Tests on concrete type cement composites included: density, mechanical strengths and deformation properties. The results showed improvement in the properties of fiber reinforced composites
 
ACTIVATION OF DOMESTIC ALUMINA AND TESTING OF POSSIBILITIES FOR APPLICATION IN SOME MINERAL BASE OILS RAFINATION
Get PDFMineral base oils are extracted from oil fractions of naphta that has boiling point of over 350 °C, and contain different kinds of carbohydrates and hetero-compunds. Removal of unwanted compunds from mineral base oils in domestic rafineries is made by rafination of imported commercial clays. For ther eventual replacement there has been conducted a testing of various domestic adsorbens. In this paper, examples of natural alumina from the vicinity of Sipovo are previously activated with sulphuric acid, and then used for rafination of naphtenic and hydrocracked base oil in laboratory conditions. Emerged changes on mineral base oils are followed by corresponding standardised methods. Results of testing showed that, by refining the given base oils with activated alumina, one can achieve good results and therefore further explorations shoud be continued, because of their commercial application in semi-industry and industry condition
BALLISTIC STRENGTH OF WOVEN FABRICS FOR PERSONAL PROTECTION
Get PDFThe purpose of the research was to make evaluation of the ballistic strength of four different fiber/resin composites intended to be used in manufacturing of ballistic items for personal protection. Research has been performed on glass, ballistic nylon, aramid and HPPE (High Performance Polyethylene) plain woven fabrics based composites. As a matrix system, in all cases, polyvinylbutyral modified phenolic resin was used. For the investigation, areal weight range 2-9 kg/m2 , applicable range for this items, and resin content range was 20 -50. %. Ballistic test of the composites has shown that the best results exhibit HPPE based composites: aramid based composites have been the second best, followed by the polyamide based composites. The worst results have been shown by the glass based composites. All the composites with lower resin content (~20 %) have performed much better than their counterparts with higher resin content (~50 %). The plot of the ballistic strength, V50 , versus areal weight has shown a linear increase of V50 with the increase of areal weight within the investigated range. The ballistic strength of the woven fabric composites is highly dependent on the fiber/resin ratio and increases with the increase of fiber content
DRYING OF SLURRIES AND PASTES IN FLUIDIZED BED OF INERT PARTICLES
Get PDFA fluid bed dryer with inert particles represents a very attractive alternative to other drying technologies according to the main efficiency criteria, i.e. specific water evaporation rate, specific heat consumption and specific air consumption. A high drying efficiency results from the large contact area and from the large temperature difference between the inlet and outlet air. A rapid mixing of the particles leads to nearly isothermal conditions throughout the bed. A fluid bed dryer with inert particles was used for drying of slurries. Experiments were performed in a cylindrical column 215 mm in diameter with glass spheres as inert particles. The effects of operating conditions on dryer throughput and product quality were investigated. Main performance criteria, i.e. specific water evaporation rate, specific heat consumption and specific air consumption, were quantified. Temperature profile along the bed was mapped, and nearly isothermal conditions were found due to thorough mixing of the particles. The industrial prototype with fluid bed of 0.8 m in diameter and capacity 650 kg of evaporated moisture per hour was realized on the basis of presented investigations on pilot unit. The most important results are 50% decrease in energy consumption and no-additional grinding of dried product in comparison with old tunnel drying technology
ENGENEERING ON THE (UN)PREDICATBLE ROADS
Get PDFA scope is given on the past and future progress of the Engineering. The origin of the term Engineering is elaborated and followed through the past. A stress is put on the Latin Ingenium, as oposed to the frequently mismatched origin in the word Engine. Further development through the Military until the Civil Engineering (and other varieties in the contemporary world) is distinguished too. A forecast is given on the possible direction of development in future, based on the experienced trends in the past
DETERMINATION OF GERMANIUM, GALLIUM, INDIUM AND THALLIUM DISTRIBUTION IN INTERPRODUCTS OF HYDROMETALLURGICAL ZINC PRODUCTION
Get PDFNowadays, due to using many rare metals in the most advanced technologies, the demand for these metals is increasing. Rare metals, however, mostly don’t show the property of creating their own mineral deposits, making their production more complicated. Some rare metals, e.g. gallium, germanium, indium and thallium usually accompany zinc ore. In the procedure of hydrometallurgical zinc production, the concentrating of these metals occurs in some interproduct processes, out of which they can be extracted. The possibility of obtaining rare metals from these sources is directly caused by the contents and quantities in specific interproducts. This paper deals with controlling the distribution of rare metals Ga, Ge, In and Tl in hydrometallurgical zinc production, in zinc plant Chemical Industry „Zorka„ in Šabac, in order to determine the places and concentration level of controlled rare metals. It is determined that In and Ga are significantly concentrated in specific output mud and precipitates from the process, and that they exist in commercially significant quantities on existing depots of these materials, while it is not the case for Ga and Tl
PREPARATION PROCEDURES OF FUNGAL PHYTO-PATHOGENS SAMPLES FOR ANALYSIS BY MALDI-TOF AND FTIR MICROSCOPY
Get PDFReliable and rapid identification of phyto-pathogens causing plant diseases is playing an important role in their control strategies. The available methods for identification of fungi are time consuming and not always very specific. MALDI-TOF and Fourier-transform infrared (FTIR) microscopy are proved to be comprehensive and sensitive analytical methods for detection of molecular changes in cells. Due to the similarity between the obtained spectra of different species of fungal pathogens, it is important to choose the most appropriate procedure for the preparation of the examined samples. Such procedure might improve the discrimination between these species. In the present study, we compared between three possible procedures of pathogen sample preparation for their examination by MALDI-TOF and FTIR microscopy. Our results showed that preparation of the fungal sample directly from liquid growth media is considered as the best way of fungal sample preparation for both MALDI-TOF and FTIR microscopy examinations
FLOTATION KINETICS OF MAGNESIUM HYDROXIDE SEDIMENTED FROM SEA WATER
Get PDFSynthetic sea water has been taken as a referential sample, in which Mg(OH)2 had been sedimented, in order to reduce biological effects and confirm reproducibility of results of the familiar composition sample. The synthetic sea water was prepared according to the scientifically developed procedure. Flotation experiments were performed in the apparatus for flotation under pressure and recoveries of floated Mg(OH)2 were determined depending on the time of flotation. The results obtained on the referential sample of the synthetic water were also tested on the sample of natural sea water and presented comparatively during work. Flotation kinetics is in most cases described by an equation of the first or second degree. However, it was established that flotation kinetics of Mg(OH)2 as chemical sediment with both types of prepared magnesium hydroxide suspension, sedimented in both the synthetic and natural sea water corresponded to the velocity of reaction n = 1.5 degree, which fully corresponds to Horst Morris’s theoretical postulates in the theory of flotation kinetics