ritnms
Not a member yet
1551 research outputs found
Sort by
Purification of sanitary-fecal wastewater at detached engineering facilities
No full textThe problem of disposal of sanitary-fecal wastewater generated at public facilities,
which cannot be connected to the sewerage system due to their distance, is solved often by
building septic tanks. Their main issue beside unpleasant odors is their frequent emptying
which increases operational costs. Lately, in these facilities septic tanks have been replaced
with purification systems, whereby the septic tank is converted into a settling tank (primary
treatment), and biological treatment is used as secondary treatment. In this paper the
possibility of adaptation of the existing system, by using a combined system with activated
sludge, based on the so-called SBR technology has been presented.Проблем одлагања генерисаних санитарно-фекалних отпадних вода на јавним
објектима који се због своје удаљености не могу прикључити на канализациону мрежу
најчешће се решавао изградњом септичких јама. Највећи проблеми њиховог
функционисања су појава непријатних мириса и потреба за њиховим честим
пражњењем, што повећава оперативне трошкове. У последње време, септичке јаме се
у овим објектима замењују системима за пречишћавање санитарно-фекалних отпадних
вода, при чему се септичка јама преуређује у таложник (примарно пречишћавање), а
као биолошки третман се користи као секундарно пречишћавање. У овом раду је
приказана могућност адаптације постојећег система уз коришћење комбинованог
система са активним муљем, на бази тзв. SBR технологије
Tehnološka ispitivanja pet alkalno aktiviranih uzoraka bentonitske rude „Bijelo Polje“-Bar“ i njihova primena u različitim industrijskim granama
No full textU ovom radu je prikazan deo tehnoloških ispitivanja koja su u ITNMS-u obavljena na 5 vrsta uzoraka (3 rovna i dva kompozita) bentonita iz ležišta „Bijelo polje “- Opština Bar. Bentonit iz ležišta „Bijelo Polje“-Bar je Ca-bentonit, i u okviru tehnoloških ispitivanja definisani su I utvrđivani uslovi njegove aktivacije i prevođenja u alkalno aktivirani Na-oblik. U radu su takođe prikazani ispitivanja mogućnosti primene neaktiviranih i aktiviranih uzoraka bentonita u livnicama. Tehnološka ispitivanja mogućnosti primene bentonita „Bijelo Polje“ – Bar u metalurgiji su obavljena u Laboratoriji za kontrolu kvaliteta sirovina i finalnih proizvoda fabrike bentonita TD ,, BENTOMAK,, - Kriva Palanka – Ginovci (S. Makedonija). Parametri kvaliteta odredjeni su saglasno postojećim ISO, ASTM, EN kao i ex-Yu standardu JUS B.F1.040 koji se odnosi na bentonite za izradu kalupa i jezgara za livenje svih vrsta odlivaka
The microstructural representation and fractal nature intepolation analysis of feldspar
No full textThis paper presents a comparative analysis of microstructural parameters by the powder X-
ray diffraction method on a polycrystalline sample and the fractal analysis. The presented
results of microstructural parameters are obtained by crystallographic programs FullProf
based on the Rietveld method. The synthetic Ba/Ca-celsian sample has been used for
microstructural parameters analysis. The feldspar sample has been synthesized by the
thermal induction phase transformation process of ion exchange Ca-LTA zeolite with Ba
cation. After the ion exchange Ba/Ca-LTA, the sample was heated at the temperature of
1300°C and the structure of Ba/Ca-feldspar was determined by the X-ray powder diffraction
analysis. The X and U shape parameters that contribute to the strain have been reconstructed
by fractal interpolation. Once we can reconstruct the shapes, which are quantum mechanics
effects, we should provide the data for predicting desired parameters mentioned previously.
We reported in this paper the successful application of this advanced and deep
microstructure analysis, which confirmed original fractal copies based on the presented
morphology characterization
Hydrophobization of calcite by wet method using stearic acid
No full textIn this paper, the results of the modification of calcite with stearic acid using the wet method are presented. In the experiments, natural limestone with a high content of calcite (greater than 95 %) was used as the starting material. The calcite surface was modified with different amounts of stearic acid - 1, 2, 3 and 4 %. The products were haracterized by thermal analysis (DTA/TGA), polarization microscopy, IR analysis and by the evaluation of a floating test. The
results of the floating test showed that hydrophobicity of the calcite surface increased with increasing the amount of stearic acid on the calcite surface and that the hydrophobicity reached
over 99 % when the concentration of stearic acid was 2 %. Thermal analysis showed that at initial concentrations of stearic acid of 2 %, surfactant molecules are chemisorbed at calcite surface
Zagađenje mikroplastikom: izvori, redukcija i remedijacija
No full textPlastični otpad i zagađenje mikroplastikom je glavni ekološki izazov i
stoga privlači sve veću pažnju društva. Eksponencijalni porast prisustva plastike
i njenih najmanjih čestica u životnoj sredini i vrstama koji je nastanjuju je
posledica primene linearne ekonomije. Tranzit s linearne na cirkulanu ekonomiju
u sistemu upravljanja plastikom je potreban u cilju redukovanja oslobađanja
mikroplastike. Kako se mikroplastika emituje u svim fazama životnog ciklusa pla-
stike, neophodno je delovanje na svim nivoima lanca vrednosti. Razvoj novih tehno-
logija proizvodnje sintetičkih polimera i inovacije remedijacionih tehnologija
čine ključne komponente za uspostavljanje modela cirkularne ekonomije
Titanium alloys database for medical applications
No full textTitanium alloys are widely applied, particularly in biomedical engineering, due to their
exceptional combination of mechanical strength, corrosion resistance, and biocompatibility.
The low modulus of elasticity of these titanium alloys in comparison to other materials used
in medical applications is a main characteristic. However, some of these alloys’ components,
such as aluminum and vanadium, can have adverse effects on the human body. Consequently,
new titanium alloys with low modulus of elasticity and no toxic alloying elements are currently
being developed. In this research, 238 titanium alloys were collected, almost entirely composed
of biocompatible alloying elements. The primary motivation behind creating such a database
is to establish a foundation for designing new alloys using machine learning methods. The
database can assist researchers, engineers, and biomedical professionals in developing
titanium alloys for various medical applications, thereby improving health outcomes and
driving advancements in biomaterials and biomedical engineering
Photocatalytic degradation of a fungicide difenoconazole and residual toxicity of its degradation products
No full textWorldwide consumption of pesticide active ingredients reaches 2.7 million tons per
year [1]. After being released into the environment significant portion of applied pesticides
ends up in surface water bodies affecting nontarget organisms. Due to high environmental
pollution, improvement in technological practices for water treatment has been a demand,
and advanced oxidation processes stand out as a prominent method. In this study,
photocatalytic degradation of a fungicide difenoconazole was investigated and residual
toxicity was assessed using zebrafish embryos (Danio rerio).
Difenoconazole has been subjected to photocatalytic degradation in presence of the
TiO2 Degussa P-25 catalyst and artificial illumination (Osram Ultra Vitalux 300 W).
Influence of different anions (carbonate, sulphate and nitrate), concentration of pesticide and
mass of catalyst, on degradation process has been assessed. Decrease in absorbance
(Shimadzu 1800 UV spectrophotometer) served as an indicator of the pesticide
concentration in the reaction system. The environmental acceptability of the specified
degradation process was assessed for optimal circumstances of total photodegradation.
Residual toxicity of degradation product was assessed on the basis of toxicity comparison
of initial, partly and completely degraded samples, according to OECD 210 [2].
Embryotoxicity assays were performed in triplicate and were terminated 120 hours post
fertilization (hpf).
According to the results of assays engaged in assessment of the influence of the ions
on photocatalytic processes, it was found that all ions have comparable catalytic effects on
the kinetics of the difenoconazole degradation process. The presence of sulphates and
carbonates had the greatest catalytic effect, while the nitrate ions showed the lowest catalytic
capacity (Fig. 1). The most suitable conditions for photodegradation were obtained by using
0.2 g/l of TiO2 and 5 mg/l of difenoconazole solution at atmospheric conditions. The
embryotoxicity assays followed the analytical examination. Comparison of results obtained
in embryotoxicity assays of the initial solution, partly and completely degraded samples
confirmed suitability of applied degradation method. Significant decrease in toxicity,
compared to the initial solution, was registered in both degraded samples. Based on
cumulative mortality (120 hpf), medium lethal concentration (LC50) of difenoconazole is 1.4
mg/l, while the same parameter could not be determined in partly and completely degraded
samples, due to the lack of mortality (Fig. 2).
According to the obtained results it can be concluded that engaged photocatalytic
degradation process is suitable for pesticide contamination water management
Nanocrystallization of potassium niobium germanate glasses
No full textThis paper presents the effect of K2O content on phase composition of the nanocrystallized niobium germanate glasses. It was shown that the exothermal peak temperature, Tp, shifted toward the higher temperatures with increasing content of K2O. Such increase of K2O content causes a decrease of GeO2 content in the primary phases. The crystals below 100 nm were detected in the samples
Preparation and characterization of chitosan–clay composites as potential drug carriers
No full textIn this study, the preparation and characterization of chitosan–clay composites as potential carriers for tetracycline were performed. The composites based on bentonite (from the deposit of Beretnica, Republic of Serbia) and chitosan were prepared. Two types of chitosan were used for the preparation of the composites: commercial low molecular weight chitosan and chitosan isolated from fruit bodies of the commercially grown mushroom Agaricus bisporus. Adsorption of tetracycline hydrochloride onto natural clay and chitosan-clay composites from aqueous media (pH 3.4) was studied. The amounts of adsorbed antibiotic were determined spectrophotometrically from the difference between the initial concentrations of tetracycline and the amounts remaining in the aqueous medium after dynamic equilibrium. Characterization of the natural clay and chitosan-clay composites before and after adsorption of tetracycline was performed by zeta potential measurements. Adsorption of tetracycline followed a nonlinear isotherm for the natural clay and composites. The Langmuir equation showed the best fit of the equilibrium adsorption data over the entire concentration range (0.05 – 1 mg/mL) and themaximum adsorbed amount of the drug on the natural clay and both chitosan-clay composites was up to ~ 200 mg/g. Only minor differences in the adsorption of the drug were observed between the composites containing commercial chitosan and the chitosan isolated from mushrooms. The observed decrease in zeta potentials of the drug chitosan–clay complexes revealed the interactions of the composite surface with tetracycline molecules. The obtained results indicate the potential of the chitosan-clay composites for the development of therapeutic systems for topical application and suggest the possibility of using fungi as a renewable source of chitosan