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Agents of different origins for reduction of mycotoxins’ level in feed
No full textToxic secondary metabolites of some fungi (mainly representatives of Alternaria, Aspergillus,Fusarium and Penicillium genera) may contaminate agricultural products, representing serioushealth hazards both to humans and animals. Along with this, the economic losses due to themycotoxins’ presence in feed production, including crop and animal feedstuff processing anddistribution, motivated the plentiful research of detoxification strategies. Feed supplementationwith mineral adsorbents (zeolites, hydrated sodium calcium aluminosilicate (HSCAS),bentonites, etc.) is the most prominent approach widely applied. Besides these, other productsfor mycotoxin level reduction based on the constituents of the yeast cell wall or Lactobacilliare often used. Recently, many investigations are directed toward plant-derived products thatcan efficiently adsorb mycotoxins in their native (biosorbents) or modified forms (e.g. activatedcarbon, biochar etc.). These renewable, easily accessible and readily prepared sorbents areeconomically viable and safe alternatives for mycotoxin decontamination of feed resources.Organic polymers (chitosan, cellulose, etc.) as well as synthetic polymers, such as polyvinylpyrrolidine, also might reduce mycotoxins’ level in feed. Besides these conventional methods,new research trends are nanotechnologies, the promising, effective, low-cost way formycotoxins’ removal. This overview systematically summarizes information on binding agentsof different origins for the reduction of mycotoxins’ levels in feed. Furthermore, the knowledgeof potential applications of binding agents in the feed industry is also reviewed and discussed
The Crystal Growth of NASICON Phase from the Lithium Germanium Phosphate Glass
No full textThe crystal growth rate of LiGe2(PO4)3 phase from lithium germanium-phosphate glass was studied. The glass have been homogenized using the previously established
temperature-time conditions, which make it possible to remove volatile substances from the glass melt. The atomic absorption spectrophotometry (AAS) was used to determine the
chemical content of the obtained glass and scanning electron microscope (SEM) were used to reveal the isothermal process of crystal growth. The crystal growth rates were determined
experimentally and theoretically
Optimization of mold design for aluminothermic welding of railway tracks by software simulation
No full textVeć više od jednog veka aluminotermijski postupak zavarivanja šina koristi se za spajanje železničkih šina. Prednosti ovog postupka su njegova fleksibilnost, kompaktnost spoja i jednostavnost izvođenja. Za njegovo izvođenje nije potrebno dovođenje energije spolja. Ona se obezbeđuje egzotermnim efektom hemijskih reakcija komponenti koje čine aluminotermijsku smešu. Jedan od bitnih elemenata za izradu zavarenog spoja zahtevanog kvaliteta je i dizajn kalupa sa ulivnim sistemom koji treba da obezbedi ravnomerno ulivanje termitnog čelika, bez turbulencija, zatim ravnomerno odvođenje toplote, odnosno hlađenje u cilju dobijanja odgovarajuće mikro i makro strukture čelika, bez unutrašnjih i spoljašnjih grešaka. Zbog toga se dizajn kalupa neprestano razvijao, koristeći skupe eksperimentalne metode u industrijskim uslovima. Danas se primenjuju softverski paketi za simulaciju klasičnih procesa livenja koji se mogu primeniti i kod izlivanja termitnog čelika tokom izrade zavarenih spojeva železničkih šina čime se izbegavaju skupa i dugotrajna ispitivanja u industrijskim uslovima. U radu su prikazani rezultati simulacije livenja termitnog čelika u kalupnu šupljinu, odnosno u šav zavarenog spoja za šinu 49E1, koristeći softverski paket NovaFlow& Solid CV. Adekvatnost rezultata simulacije proverena je izradom probnih zavarenih spojeva u industrijskim uslovima i ispitivanjima njihovog kvaliteta, shodno EU 13740-1:2017 standardu.The aluminothermic welding process of rail welding has been used to join railway rails for more than a century. The benefits of this procedure include its flexibility, compactness of the weld, and ease of execution. It is not necessary to bring in outside energy to complete the process. It is provided by the exothermic effect of the chemical reactions of the aluminothermic mixture's constituents. The design of the mold with the pouring system, which should ensure even pouring of thermal steel, without turbulence, then even heat dissipation or cooling in order to obtain appropriate micro and macro structure of steel, without internal and external defects, is an important element for making a welded joint of the required quality. As a result, the mold's design was constantly evolving, requiring the use of costly experimental methods in industrial settings. Today, software packages are used to simulate traditional casting processes that can be used in the casting of thermite steel during the manufacture of welded railway joints, thereby avoiding costly and time-consuming industrial tests. The simulation of casting thermite steel in the mold cavity, i.e. in the weld joint for the 49E1 rail, using the NovaFlow & Solid CV software package, is presented in this paper. The simulation results were validated by establishing test welded joints in industrial settings and testing their quality in accordance with the EU 13740-1: 2017 standard
Synthesis of the new lost foam refractory coatings based on talc
No full textThis paper is focused on the preparation procedures, using a talc-based filler, to improve the rheologic properties of the lost foam refractory coatings. Talc, with grain size of 40 .m, was mechanically activated in a vibration mill over the following times: 10, 20 and 30 min. Depending on the time required for the mechanical activation, the change in the filler grain size and shape was analysed along their effects on the talc-filled lost foam coating dispersion ability and stability. In order to characterize the filler, the following methods were used: X-ray diffraction, scanning electron microscopy and optic microscopy. The coating composition was tuned by choosing the suitable grain size and shape factor of the activated filler. In addition, different coating components (additives, solvent) were applied to alter the coating generation procedure. It was shown that the application of this type of the lost foam refractory coatings - water-based coatings - have a positive influence on quality of the aluminium alloy castings, which contributes to reducing the cost of cleaning and processing of the castings. Also, alcohol-based refractory coatings with talc-based activated fillers were tested and used to have the castings produced in the sand moulds
Reciklaža otpada koji sadrži materijale na bazi karbonatnih mineralnih sirovina
No full textU radu je prikazan značaj reciklaže otpada na bazi karbonatnih mineralnih sirovina nastalog u oblasti građevinarstva. Ova vrsta otpada može negativno da utiče na životnu sredinu ako se sa njime ne postupa na propisan način. Reciklaža je jedino rešenje za smanjenje količine građevinskog otpada koji se nalazi na deponijama. Kako bi se građevinske firme stimulisale da prihvate reciklažu otpada, kao sastavni deo svog poslovanja, države sprovode različite strategije za unapređenje primene reciklaže u praksi. Podsticaj reciklaže, korišćenja sekundarnih sirovina i razvoj alternativnih tehnologija su izuzetno važni sa aspekta održivosti prirodnih resursa koji su neobnovljivi ili teško obnovljivi. Pozitivna iskustva razvijenih zemalja u oblasti reciklaže, mogu da nam budu dobar primer za uspešnu sanaciju otpada i u našoj zemlji
Sintering and Phase Transition of the ZnTiO3 Nano Powder Dilatometric Data Deconvolution
No full textSintering and phase transition are often superimposed at dimensional change diagram recorded during heating. Phase transition kinetic is thus hard to deconvolute due to the superposition of the sintering and phase transition dimensional change phenomena.
Metastabile perovskite phase ZnTiO3 has transition to stabile spinel Zn2TiO4 which occurs at 945oC with high kinetic rate. Nano powder with 40 nm particle diameter was pressed uniaxially at 200 MPa pressure without binder to form compact that will be consequently sintered. Dimensional change during heating was monitored using dilatometric thermo-mechanical analyzer TMA model SETSYS Evolution. Lever`s rule was used to calculate amount of the emerging phase during phase transition.
The compacted specimens were treated on the non-isothermal schedule up to 1050oC.Sintering phenomenon of the ZnTiO3 nanopowder compact was also recorded up to 900oC with isothermal holding of 25 minutes where phase transition was avoided due to lower temperature and isothermal holding. Second run heating of the obtained sintered specimens were recorded with the heating schedule of non-isothermal heating up to 1050oC.
Kinetic of the phase transition was obtained from dilatograms recorded during sintering and from bulk on the second run heating. Furthermore, phase transition kinetics was obtained by subsequent data subtraction of the sintering curves without phase transition from the dilatation sintering curves containing phase transition.
In such a manner complex kinetics of phenomena such as sintering, linear expansion and phase transition recorded as dimensional change during heating brings the recognition of their mutual interconnected relations. Also application of these mathematical operations on dilatometric data leads to the established procedure for the sintering and phase transition data treatment
Sinter-crystallization of coal fly ash based glass
No full textThe increasing production of coal fly ash waste from thermal power plants has compounded environmental and economical problems worldwide. In this research coal fly ash was mixed with glass cullet and CaCO3 and melted at T= 1500 °C. The glass was milled, pressed and sintered at T= 900 °C to obtain glass- ceramic. Obtained glass- ceramic was well sintered with low crystallinity. This material, produced from secondary raw materials, could find potential application in building industry as substitute for commercial wall and floor tiles
Phophate glassy fertilizers
No full textThe main goal of agricultural production should be the production of a sufficient amount of agricultural products with the least possible impact on the environment. In traditional agricultural production, in order to obtain a satisfactory yield, artificial fertilizers are used, which have multiple negative impacts on the environment. Glassy fertilizers are a type of fertilizer that, at least according to previous research, do not have a negative impact on the environment and the same time the use of these fertilizers yields not less than when using traditional fertilizers. Glassy fertilizers are fertilizers with controlled dissolution, they do not pollute groundwater or surface water, the pH of the soil does not change with their use, by changing the composition they can adapt to the requirements of each crop individually, etc. The paper presents three phosphate glassy fertilizers of different chemical composition, obtained at the Center for Inorganic Technologies, ITNMS. The method of obtaining of glassy fertilizers, their dissolution rates in a medium that simulates soil conditions, the changes in pH values of solutions for different dissolution times and the effect of temperature on dissolution rates are shown. Also, the results of the influence of glass fertilizers on plant cultures in real conditions are presented
Orchid-soil System Relationship in the Serpentine, Silicate and Limestone bedrocks
No full textAnacamptis morio occurs on a wide range of habitats showing distinct tolerance to heterogeneous
edaphic conditions. Assessment of Li, B, Ba, and Sr phytoavailability in the soils of western
Serbia, and metal(oid) uptake by A. morio provided new information on less studied elements and
revealed their relatively high mobility in the soil-orchid system. Although previous studies have
found that A. morio prefers neutral and calcareous soils, our study shows that it also inhabits ultramafic
and siliceous sites characterized by pronounced differences in soil chemical properties. BCR
sequential extraction identified up to 60% of Li and more than 80% of Ba and Sr content as potentially
phytoavailable. The total element analyses using ICP-OES showed that B, Ba and Sr predominantly
accumulated in the roots, but did not exceed thresholds considered potentially phytotoxic.
It revealed the exclusion strategy of A. morio which enables it to tolerate differences in elemental
composition of contrasting bedrock types. The highest Li concentrations were detected in leaves,
pointing to significant Li mobility within the plant. The contents of Li and Ca were highly positively
correlated, which may result from Li physicochemical properties that are similar to those of alkali
metals, allowing it to share the same transport carriers. Thus, Li could be easily transported to the
aboveground plant parts and accumulated mainly in the organs with the highest Ca content,
which was confirmed in this study. Bioconcentration factors >1 were detected only for B and Sr in
all plants analyzed, irrespective of the bedrock type
Different approaches to microplastic extraction from soils
No full textMicroplastic particles (MPs) emergence and expansion have occurred rapidly and almost imperceptibly on a worldwide basis. Its presence and persistence in terrestrial environments recently started attracting considerable attention from scientific researchers, policymakers, the media, and the general public. Several methods were developed in order to isolate MPs from complex soil samples. Density separation demonstrated to be the most efficient and cost-effective to date It consists of the following steps: soil sieving, grinding and measuring, MPs extraction using the saturated salt solution of the appropriate density higher than the MPs that need to be isolated, supernatant filtration, and visualization of MPs adhered to filter. Several approaches could be applied to soil MPs separations, considering the utilization of different extracting solutions, working conditions, and phases order, which we investigated herein. As soil samples contained around 5% of organic matter (OM), the first protocol implied organic matter digestion using 30% H2O2 before the extraction, while the second one was performed vice versa. In both protocols, the extraction solvent that was used was saturated NaCl solution, density 1.2 g cm-1. According to the obtained results, and bearing in mind the fact that MPs could be entrapped in soil aggregates, OM digestion before the extraction was considered suitable to continue the investigation. In the following protocol, digestion was conducted at different temperatures and durations of 7 days at 25˚C (room temperature) and 24h at 60˚C, respectively, which enabled more efficient OM removal. The temperature and time of exposure may need additional tuning according to the soil type. While using NaCl solution, only polymers with a density lower than 1.2 g cm-1 could be extracted, so in the next procedure, it was replaced by a saturated solution of ZnCl2, which density could go up to 1.9 g cm-1. Hence, the final protocol based on the previous optimization involved digestion with H2O2 at 60˚C for 24h, followed by covering the dry residue with saturated ZnCl2 solution. The mixture was left overnight for density separation. The upper layer of the solvent where the MPs tend to concentrate was taken by a glass dropper and filtered through a Whatman glass filter (pore size 1.6 μm, diameter 25 mm). Achieved efficiency regarding OM reduction rate and MPs extraction on examined soils was satisfactory for further investigations