On approximations by trigonometric polynomials of classes of functions defined by moduli of smoothness

In this paper, we give a characterization of Nikol'ski\u{\i}-Besov type classes of functions, given by integral representations of moduli of smoothness, in terms of series over the moduli of smoothness. Also, necessary and sufficient conditions in terms of monotone or lacunary Fourier coefficients for a function to belong to a such a class are given. In order to prove our results, we make use of certain recent reverse Copson- and Leindler-type inequalities.Comment: 18 pages. arXiv admin note: substantial text overlap with arXiv:1208.612

On Approximations by Trigonometric Polynomials of Classes of Functions Defined by Moduli of Smoothness

In this paper, we give a characterization of Nikol'skiȋ-Besov type classes of functions, given by integral representations of moduli of smoothness, in terms of series over the moduli of smoothness. Also, necessary and sufficient conditions in terms of monotone or lacunary Fourier coefficients for a function to belong to such a class are given. In order to prove our results, we make use of certain recent reverse Copson-type and Leindler-type inequalities

Enriching of Magnesite Ore Containing Dolomite

Glavne primjese magnezitne rude rudnika "Strezovce" su minerali silicija i kalcija koji nepovoljno utječu na vatrostalnost proizvoda na osnovi magnezijevog oksida. Stoga se proizvodnja i prerada magnezitne rude provodi s ciljem smanjenja njihovog masenog udjela. Za uklanjanje primjesa minerala silicija postoje razrađeni tehnološki postupci, dok je uklanjanje primjesa minerala kalcija samo na osnovu mehaničkih separacijskih operacija nezadovoljavajuće. U ovom su radu prikazani rezultati istraživanja utjecaja temperature i vremena žarenja magnezitne rude te načina naknadne hidratacije na oplemenjivanje sirovine u taložnom separatoru s gustom suspenzijom. Istraživanja su pokazala da je optimalna temperatura žarenja rude od 600 - 700 °C tijekom 4 i 6 h, a nakon hidratacije i taložne separacije ρ = 2,20 g cm-3 dobiva se sirovina sa smanjenim udjelom kalcija i silicija. Procesom hidratacije u dinamičkim uvjetima zbog usitnjavanja materijala nastaju velike količine sitne klase, manje od d = 0,5 mm, koja nepovoljno utječe na udjel kvalitetnog proizvoda. Tijekom hidratacije potapanjem žarenog materijala to se ne događa. U radu je ustanovljen i povoljan utjecaj produljene termičke obrade na iskorištenje proizvoda te optimalna gustoća guste suspenzije za dobivanje kvalitetnog proizvoda.Minor mineral phases containing calcium and silica in magnesite ore are the main cause of detrimental properties of magnesia refractory materials prepared thereof. All stages of the production process aim to remove such unwanted mineral phases. While the removal of silica minerals is well documented, it is not so for the calcium containing minerals, especially when it is not possible to do so by mechanical separation processes only. In this work, the influence of duration and temperature of heat treatment and subsequent hydration of magnesia has been studied. The final product obtained is a light component from the settling separation utilizing dense water suspension of ferrosilica. The optimal process conditions were: 4 to 6 h soaking at temperature between 600 and 700 °C with subsequent hydration of partially calcined product by immersion in water and settling separation at heavy fluid density ρ= 2.20 g cm–3. Furthermore, a positive influence of prolonged heat treatment on product quality as well as the optimal density of ferrosilica suspension has been obtained

Comparative study of inhibitory efficacy of methionine and its derivatives in acidic medium by mild steel

Corrosion inhibition effect of L-Methionine (MT1), L-Methionine sulfoxide (MT2) and L-Methionine sulfone (MT3) on mild steel corrosion in 1M HCl solution was studied by using weight loss, electrochemical polarization and electrochemical impedance spectroscopy (EIS) techniques. The experimental results showed that the inhibitory efficiency of the three aminoacids improves with the increase of concentration to reach the maximum value of 95.20% for MT1, 94.14% for MT2 and 88.92% for MT3 for a concentration of 10-3M, which translates that the surface covered by the inhibitor increases with the concentration. The effect of temperature on the corrosion rate was investigated and some thermodynamic parameters were calculated. Polarization studies show that three studied inhibitors suggested that three inhibitors control the anodic as well as cathodic reactions and act as mixed type in nature. The results show that MT1, MT2 and MT3 are good inhibitors, and the adsorption of each inhibitor on mild steel surface obeys Flory-Huggins and Langmuir, with a better fit of the Langmuir isotherm through mixed adsorption (physisorption as well as chemisorption) process. In addition, the quantum approach based on density functional theory (DFT), monte Carlo (MC) and molecular dynamics (MD) simulations was confirmed the reactivity of the studied compound towards the corrosion process

Amino Acid and Biogenic Amine Composition of Busha Cattle Milk

To our knowledge, there is a lack of information on the nutrient composition of Busha cattle milk with special regard to its amino acid and biogenic amine contents. The Busha cattle breed is known to be highly resistant to various diseases and well-adapted to the extensive breeding conditions of the Balkan Peninsula. Busha cow milk contains an average of 13.47% dry matter, 4.34% fat, 3.72 % protein, and 4.32% lactose. Significant differences were detected (P < 0.05) in the amino acid compositions of the milk of different Busha cattle strains of Kosovo. Glutamic acid, proline, leucine, aspartic acid, lysine, and valine represented 68% of the total amino acid content. Essential amino acids, branched-chain and sulphur-containing amino acids were found in substantial amounts in the milk samples. Among the biogenic amines, however, spermine (0.16 mg kg1) and cadaverine (0.09 mg kg1) were present in low concentrations. Due to these excellent qualities of the Busha cow milk, preservation of this cattle breed is of great importance. Developing sustainable and secured breeding and feeding programs for this endangered cattle breed of the Balkan Peninsula should also be a high priority