Sol-gel synthesis and characterization of iron doped mullite

Предмет ове докторске дисертације је синтеза мулита допираног гвожђем у опсегу састава од 3–15 мас% Fe2O3 применом колоидног сол-гел поступка у комбинацији са методом сагоревања. Након синтезе, извршена је карактеризација синтетисаних и термички третираних прахова прекурсора мулита. Методом диференцијалнo-скенирајуће калориметрије утврђено је да се процес формирања мулита одвија у два ступња, што указује на двофазну природу синтетисаних прахова прекурсора мулита...The subject of this doctoral dissertation is the synthesis of iron doped mullite in composition range 3 – 15 wt% Fe2O3 employing colloidal sol-gel technique combined with combustion synthesis method. After synthesis, characterization of synthesized and thermally treated mullite precursor powders was performed. The DSC/TGA analysis reported that the mullitization is two-step process, which reveals the diphasic nature of synthesized precursors..

The effect of acrylate on the properties and machinability of alumina ceramics

Effect of methyl methacrylate (MMA) as a binder and heating treatment were investigated to improve green alumina compacts machinability. Properties of green compacts and their corresponding sintered samples prepared with and without MMA were compared. Investigation of green and sintered properties was performed on samples compacted at applied pressures up to 150 MPa. After pressing, samples with MMA were thermally treated at 115oC. The intention was to enhance the polymerization of MMA at a temperature a little higher than the glass transition temperature (Tg = 103oC) of poly (methyl methacrylate). Green compacts with MMA had higher green density values than those without MMA. Sintered samples with MMA had lower values of sintered density and higher values of total porosity; after sintering, relative linear shrinkage was around 15 % for the whole range of applied pressures. The possibility of easily machining the green compacts with MMA produces great possibilities for application in many field

The significance of adiponectin as a biomarker in metabolic syndrome and/or coronary artery disease

© 2015, Institut za Vojnomedicinske Naucne Informacije/Documentaciju. All rights reserved. Background/Aim. Adiponectin exerts profound protective actions during insulin resistence or prediabetes progression towards more severe clinical entities such as metabolic syndrome and/or cardiovascular disease. Since hypoadiponectinaemia contributes to the pathophysiology of the metabolic syndrome and coronary artery disease the level of circulating adiponectin may be an early marker of cardiovascular events. The aim of this study was to determine the relationships between serum adiponectin levels and parameters of both insulin sensitivity and obesity in patients with the metabolic syndrome and/or coronary artery disease, as well as to assess predictive value of adiponectin serum levels as a biomarker of these entitetis. Methods. The study included 100 patients with metabolic syndrome and/or coronary artery disease with different degree of insulin resistance and healthy, normoglycemic individuals. The control group comprising healthy, normoglycemic individuals was used for comparison. Serum level of adiponectin, fasting glucose, fasting insulinemia Homeostasis Model Assessment of Insulin Resistance (HOMAIR) index and anthropometric parameters were determined in all the subjects. Adiponectin was measured by using the ultrasensitive ELISA method. Insulinemia was measured by the radioimmunoassay (RIA) method. The presence of glycemic disorders was assessed on the basis of oral glucose tolerance test (OGTT). Results. Adiponectin level was inversely correlated with age (ϱ = - 0.015), parameters of both obesity (R = 0.437; p < 0.001) and insulin resistance (R = 0.374; p < 0.01). Decreasing in the level of adiponectin was strongly implicated in the development of insulin resistance. Most importantly, a statistically significant rapid decrease in adiponectin was in the prediabetic stages (p < 0.01). The predictor value of adiponectin was 1,356.32 ± 402.65 рg/mL. Conclusions. The obtained resultats suggest that adiponectin may be a useful marker in identification of individuals with risk of developing metabolic syndrome and coronary artery disease, as well as a predictor of prediabetes

Dužina peteljki sirka metlaša pri različitom sklopu biljaka

Bromcorn fiber length is determined by measuring the distance between the point at which the fibers start to branch out and the tip of at least two thirds of all the fibers present in a given panicle. This is a very important morphological trait, as it determines the success of the panicle harvest. A two-year investigation was carried out in order to determine the influence of different stand densities on fiber length levels in two broomcorn genotypes. Two row-to-row spacing (50 and 70 cm) and six plant-to- plant ones (5, 9, 13, 17, 21, and 25 cm) were studied. Fiber length was the smallest (42.6 and 45.2 cm) with the highest stand densities, and it increased with increasing plant growing space (63.7 cm and 71.0 cm). .Dužina peteljki sirkovih metlica predstavlja rastojanje između tačke grananja peteljki i mesta gde se nalazi vrh najmanje 2/3 od ukupnog broja peteljki. Ovo je veoma bitna morfološka osobina biljaka sirka metlaša, od koje zavisi uspešnost žetve sirkovih metlica. U cilju sagledavanja promene dužine peteljki sirkovih metlica u zavisnosti od različitog sklopa biljaka, izvršena su dvogodišnja istraživanja sa dva genotipa sirka metlaša. Ispitivana su dva međuredna razmaka od 50 i 70 cm i šest različitih razmaka biljaka u redu, (5, 9, 13, 17, 21 i 25 cm). Dužina peteljki bila je najmanja pri najgušćim sklopovima 42,59 i 45,22 cm, dok je sa povećanjem vegetacionog prostora dužina peteljki bila sve veća - 63,72 i 71,04 cm

Application of FeAl-LDH@SiO2 for Phosphate Removal from Water

In present study FEAL-LDH@SIO2 were Used for removing phosphate from aqueous solutions. FeAl-LDH with molar ratio Fe/Al = 3/1 was synthesized by co- precipitation from aqueous solutions in the present of SIO2 PARTICLES. Silica obtained from rice husks were used as a substrate for the deposition of LDH particles. The prepared material was characterized by scanning electron microscope (FE-SEM), X-ray diffraction (XRD), N2 adsorption/desorption isotherms (BET method) and Fourier transform infrared spectroscopy (FTIR). XRD analysis showed that Fe-Al had formed LDH structure. SEM analysis revealed deposition of LDH particles on SIO2 SUBSTRATE. The adsorption characteristics for phosphate uptake of the obtained material were performed. Adsorption experiments were carried out as a function of LDHs dosage with three different mass ratios of LDH/silica = 1/1, 2/1, and 3/1 and different phosphate concentration AT INITIAL PH 4. Phosphate concentrations were determined using spectrophotometer. The results showed that the maximum sorption capacities of phosphates calculated based on Langmuir equation was 52.68 mg g-1.The book of abstract available at: [http://conf.univerzitetpim.com/wp-content/uploads/2022/06/Book-of-Abstracts_2022-1.pdf

Synthesis and characterization of (Ba,Yb) doped ceria nanopowders

Nanometric size (Ba, Yb) doped ceria powders with fluorite-type structure were obtained by applying selfpropagating room temperature methods. Tailored composition was: Ce0.95−xBa0.05YbxO2−δ with fixed amount of Ba − 0.05 and varying Yb content “x” from 0.05 to 0.2. Powder properties such as crystallite and particle size and lattice parameters have been studied. Röntgen diffraction analyses (XRD) were used to characterize the samples at room temperature. Also, high temperature treatment (up to 1550°C) was used to follow stability of solid solutions. The mean diameters of the nanocrystals are determined from the full width at half maxima (FWHM) of the XRD peaks. It was found that average diameter of crystallites is less than 3 nm. WilliamsonHall plots were used to separate the effect of the size and strain in the nanocrystals

Uticaj potapanja semena soje na klijavost i životnu sposobnost u zavisnosti od partije i roka setve

The objective of this paper was to examine the effect of seed lot, sowing date, and priming on germination and vigour of soybean seed. Three different seed lots of an old soybean variety (Lot 1, Lot 2, Lot 3) created at the Institute of Field and Vegetable Crops in Novi Sad were used. There were three sowing dates: 10 April, 20 May and 20 June. KNO3 (1%), H2O2 (0.1%), GA3 (0.075%) and distilled water were used as primers. The results showed that soaking the seed prior to sowing, so called priming, positively affected seed germination and vigour in all three lots and with all three sowing dates. The best effect was accomplished with Lot 1 and sowing on the third date. With regards to primers, the best effect was achieved with the application of KNO3 and H2O2 solutions. Research has shown that even soaking the seed in distilled water, which is a simple, cheap, and ecological method of priming, in most cases leads to improvement of germination and vigour of soybean seed.Cilj ovog rada bilo je ispitivanje uticaja partije, rokova setve i rastvora za potapanje na klijavost i životnu sposobnost semena soje. Kao materijal poslužile su tri partije semena soje (partija 1, partija 2, partija 3) stvorene u Institutu za ratarstvo i povrtarstvo u Novom Sadu. Setva je izvršena u tri roka: 10. aprila, 20. maja i 20. juna. Kao rastvori za potapanje korišćeni su KNO3 (1%), H2O2 (0,1%), GA3 (0,075%) i destilovana voda. Rezultati su pokazali da je potapanje semena pre setve (prajmiranje) imalo povoljan uticaj na klijavost i životnu sposobnost semena kod sve tri partije, ali i kod sva tri roka setve. Najbolji efekat ostvaren je kod partije 1 i setvom u trećem roku. Primenom rastvora kalijum-nitrata, odnosno vodonikperoksida postignut je najbolji efekat. Istraživanja su pokazala da čak i potapanje semena u destilovanu vodu, što predstavlja jednostavan, jeftin i ekološki metod, u većini slučajeva dovodi do poboljšanja klijavosti i životne sposobnosti semena soje