Realization of a digital rate meter as an IIR digital filter by implementing an optimized signal processing algorithm

By applying the well known dualism: mean count rate - mean time between successive pulses - the equivalence between an IIR digital filter and a preset count digital rate meter has been demonstrated. By using a bank of four second order IIR filters and an optimized automated algorithm for filter selection, a practical realization of a preset count rate meter giving good tradeoff between statistical fluctuations and speed of response, particularly at low count rates such as background monitoring, is presented. The presented solution is suitable for designing portable count rate meters. The designed prototype is capable of operating up to 3600 pulses per second with an accuracy of over 4% in steady-state and response times of 1 second for the rising edge and 2 seconds for the falling edge of the mean count rate step-change

Macroporous monoliths based оn natural mineral sources, clay аnd diatomite

Macroporous silica ceramic was obtained using clay and diatomite. Boric acid as a low-cost additive in the amount of 1 wt% was used. These porous materials were obtained at low forming pressure (40-80 MPa) and lower sintering temperature (850-1300 ºC) for 4h in air. The influence of boric acid, forming pressure, and sintering temperature on the microstructure, porosity parameters, and mechanical properties of obtained porous monoliths were investigated. As-received and the modified samples were characterized by X-ray diffraction, FTIR, SEM, and mercury porosimetry measurements. As for modified clay and diatomite, they were pressed at 60 MPa and then sintered at 1150 ºC, obtaining porosities of about 10 % and 60 %, respectively. Both of the analyzed samples had the pore diameter in the range of macroporous materials. The pore diameters of clay samples are ranging from 0.1-10 μm, whereas the pore diameter of diatomite samples was slightly lower with values ranging from 0.05-5 μm. Modified diatomite samples have a lower Young modulus in comparison to modified clay samples

Iron (III) Oxide Fabrication From Natural Clay With Reference to Phase Transformation gamma- - GT alpha- Fe2O3

Amorphous iron (III) oxide was obtained from clay, using ammonium hydroxide as a precipitating agent. Influence of freeze drying under vacuum, as a drying method, on particle size, chemical composition, and crystallinity of obtained iron (III) oxide powder was investigated. After freeze drying, precipitate was annealed in air at 500 C-o and 900 oC. X-ray diffraction, particle size analysis, scanning electron microscopy, energy dispersive spectrometry, Fourier transform infrared spectroscopy, thermogravimetric and differential thermal analysis were used to characterize obtained iron (III) oxide powder. All of three powders obtained by freeze drying and annealing, have low crystallinity and particles with irregular layered shape. Narrow particle size distribution was given by an average diameter value of around 50 mu m for all observed powders. Iron-bearing materials like a-Fe2O3 and gamma-Fe2O3 are obtained. Differential thermal analysis curve of obtained samples showed endothermic reaction at 620 oC which could be ascribed to phase transition from cubic form gamma- - GT alpha- Fe2O3. Thermal transformations of iron (III) oxide, obtained from clay as a natural source, is suitable to explore in the framework of materials chemistry, and opens the possibility to synthesize materials based on Fe2O3 with specific magnetic behavior

Application of methyl methacrylate for pressing and machining of alumina green ceramics

The addition of methyl methacrylate (MMA) in the amount of 2 mas% in the alumina mixture improved the pressing of alumina and achieved excellent quality of machining of green compacts. The compressibility test determined the optimal pressing pressure of alumina with MMA of 60 MPa. The value of green densities was analyzed depending on applied pressure up to 150 MPa. The exceptionally smooth and shiny surface of green compact indicates good pressing of alumina with MMA. After pressing, the samples were thermally treated at 115 o C to activate the side groups of MMA polymer chains at a temperature slightly higher than the glass transition temperature (103 o C) of PMMA. This way was to improve the strength of the green compact. Compacts prepared with MMA had higher values of green density and lower values of sintered density, total and open porosity than compacts without MMA. After sintering at 1620 o C, the relative linear shrinkage was about 15% for the entire range of applied pressing pressures. The machining of the green compact enables the precise production of complicated forms of technical ceramics for the needs of many areas of the economy.X Serbian Ceramic Society Conference - Advanced Ceramics and Application : new frontiers in multifunctional material science and processing : program and the book of abstracts; September 26-27, 2022; Belgrad

Structural characterization of Kalsilite

Thermally induced phase transformation of K-exchange LTA zeolite is followed in the range from room temperature to 1500 ºC. The frameworks collapse into amorphous intermediate products after heating between 600 and 650 °C. Prolonged heating of the intermediate product over 1100 °C results directly in formation a kalsilite [a= 8.1095 (4) Å, b =12.824 (4) Å, c =7.0674 (4) Å, β =115.89 °(3)]. The crystale phases of kalsilite in temperature range between 700 and 1500°C was investigated by X-ray powder analyses

Gajenje semenskog kukuruza na različitim tipovima zemljišta

The trial was carried out to examine the influence of two different soil types (alluvium and marshy black soil) on the grain yield of two maize seed crops, during two diametrically opposite growing seasons under intensive irrigation. The same soil management was applied during both seasons. The sowing density of parental inbreds in the second season was increased in the first hybrid (H1) by 7% and decreased in the second hybrid (H2) by 25%. Generally, the achieved grain yield was significantly lower on marshy black soil in regard to cropping on alluvium. The change in the plant density of parental components was reflected on the grain yield of both hybrids, increasing it on alluvium, averagely by 25% and on marshy black soil by 27%. On the other hand, marshy black soil was characterized as poorer soil for H2 cropping, because a lower yield was achieved (by 4%), compared to H1, while the opposite situation was present on alluvium, where the grain yield higher by 13% was obtained in H2, compared to H1, indicating that H2 parental components should be cropped on light soils.Cilj ogleda je bio da se ispita uticaj dva različita tipa zemljišta (aluvijuma i ritske crnice) na prinos dva hibrida semenskog kukuruza tokom dve dijametralno različite sezone, u uslovima intenzivnog navodnjavanja. Primena agrotehničkih mera tokom obe sezone je bila ista osim smanjenje gustine setve roditeljskih linija kod prvog hibrida (H1) za 7%, dok je kod drugog (H2) izvršeno povećenje setvene gustina roditeljskih linija za 25% u drugoj sezoni. Generalno, postignuti prinosi su bili značajno niži na ritskoj crnici, u odnosu na gajenje na aluvijumu. Promena u setvenoj gustini roditeljskih komponeneti se odrazila na povećanje prinosa kod oba hibrida na aluvijumu prosečno za 25%, dok je na ritskoj crnici došlo do povećanja za 27%. Sa druge strane, ritska crnica se pokazala kao loše zamljište za H2, jer su kod njega postignuti za oko 4% niži prinosi u odnosu na H1, dok je na aluvijumu situacija bila obrnuto proporcionalna, sa 13% višim prinosima kod H2, u odnosu na H1, što ukazuje da je roditeljske komponenete ovog hibrida potrebno gajiti na lakšim zemljištima

Postindustrial Jute Waste as a Support for Nano-Carbon Nitride Photocatalyst: Influence of Chemical Pretreatment

Non-woven jute (NWJ) produced from carpet industry waste was oxidized by H2O2 or alkali-treated by NaOH and compared with water-washed samples. Changes in the structure of the NWJ, tracked by X-ray diffraction (XRD), showed that both chemical treatments disrupt hydrogen bond networks between cellulose Iβ chains of the NWJ fibers. Thereafter, nano-carbon nitride (nCN) was impregnated, using a layer-by-layer technique, onto water-washed jute samples (nCN-Jw), NaOH-treated samples (nCN-Ja) and-H2O2 treated samples (nCN-Jo). Analysis of the Fourier transform infrared spectroscopy (FTIR) spectra of the impregnated samples revealed that nCN anchors to the water-washed NWJ surface through hemicellulose and secondary hydroxyl groups of the cellulose. In the case of chemically treated samples, nCN is preferentially bonded to the hydroxymethyl groups of cellulose. The stability and reusability of prepared nCN-jute (nCN-J) samples were assessed by tracking the photocatalytic degradation of Acid Orange 7 (AO7) dye under simulated solar light irradiation. Results from up to ten consecutive photocatalytic cycles demonstrated varying degrees of effectiveness across different samples. nCN-Jo and nCN-Ja samples exhibited declining effectiveness over cycles, attributed to bond instability between nCN and jute. In contrast, the nCN-Jw sample consistently maintained high degradation rates over ten cycles, with a dye removal percentage constantly above 90%

Surface modification of TiO2 nanoparticles with catechol

Surface modification of nanocrystalline TiO2 particles with catechol was found to result in a red shift of the semiconductor absorption compared to unmodified nanocrystallites. The undercoordinated defect sites at TiO2 surface are the source of novel enhanced and selective reactivity of the nanoparticle toward bidentate ligand binding. Catechol, an enediol ligand, have the optimal geometry for chelating surface Ti atoms, resulting in a five-membered ring coordination complex and restoration of six-coordinated octahedral geometry of surface Ti atoms.Physical chemistry 2008 : 9th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 200

Preparation and characterization of clay and diatomaceous earth based porous ceramics with boric acid as additive

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