Proučavanje uzajamnog djelovanje kisika i vodene pare sa čistim i vodikom prekrivenim tankim slojevima željeza mjerenjem površinskih potencijala

Oxygen adsorption on both clean and hydrogen-precovered thin Fe films has been investigated by measuring the surface potential (SP), gas phase composition and the total gas pressure at 298 K. The results were supplemented by SP studies of water-vapour adsorption on clean and oxygen-precovered thin iron films. Oxygen interaction with Fe film pre-exposed to water-vapour has also been studied at 298 K. It has been observed that only a small part of the initially deposited hydrogen desorbs due to the competitive adsorption of oxygen. Most of the hydrogen adspecies remain on the surface diminishing the amount of adsorbed oxygen and affecting the electrical character of the oxygen adsorbate. Water adsorbs dissociatively on clean Fe film at 298 K, decreasing the SP. Precovering Fe film with O2 at 298 K prevents the decomposition of water. The amount of oxygen consumed is only slightly diminished by water preadsorbed on clean Fe film at 298 K.Proučavana je adsorpcija kisika na čistim i vodikom prekrivenim tankim slojevima željeza mjerenjem površinskog potencijala, sastava plina i ukupnog tlaka na 298 K, kao i adsorpcija vodene pare na čistim i kisikom prekrivenim tankim slojevima željeza. Proučavano je, također, međudjelovanje kisika s Fe slojem prethodno izloženom vodenoj pari. Prekrivanje Fe sloja s kisikom na 298 K spriječava dekompoziciju vode. Količina potrošenog kisika samo se malo smanjuje preadsorbiranom vodom na čistom Fe sloju na 298 K

Ispuštanje atomskog deuterija iz površine paladijevog deuterida

Deuterium desorption from the surface of decomposing palladium deuteride was studied by monitoring the atomic component of the desorbing gas using an adsorption method. A thin gold film was applied as an adsorbent active for D adsorption, but inert to D2 adsorption. The deuterium deposit thereby collected on the Au surface was analysed by means of the thermal desorption mass spectrometry (TDMS). The atomic component of deuterium, arising by desorption from decomposing PdDy was clearly detected. The experimental results obtained for PdDy, are compared with those observed during the decomposition of PdHx.Proučavana je desorpcija deuterija s površine raspadajućeg PdDy mjerenjem atomske sastavnice desorbiranog plina. U tu je svrhu upotrebljen tanak listić zlata aktiviran za D adsorpciju, a inertan za D2 adsorpciju. Deuterij sakupljen na zlatu analiziran je termičkom desorpcijskom masenom spektrometrijom. Eksperimentalni rezultati za PdDy se uspoređuju s rezultatima za desorpciju iz PdHx

NUMERICAL SIMULATION AND CO-SIMULATION IN ANALYSIS OF MANIPULATORS’ DYNAMICS

Application of general purpose computing environments to analysis of manipulators’ dynamics gives ability to select elastically the model structure and analysis algorithms, as well as full access to the intermediate results, however, it often requires introduction of various simplifications of the model under consideration. The alternative approach consists in application of the specialized software packages that allow the use of more sophisticated models, but at the cost of restricted access to the intermediate results as well as the limited range of possible modifications of models and solution algorithms. The authors focused on application of the co-simulation technique in analysis of manipulators’ dynamics. Co-simulation consists in application of specialized software packages to formulation of the dynamic model. Next, the model is simulated with use of a general purpose computing environment and co-operating specialized software package. The authors used Matlab/Simulink computing environment and MD ADAMS software package. The paper presents comparison of results, problems of application, as well as remarks on educational applicability of manipulator dynamics analysis with use of the simulation and the co-simulation techniques. Two examples of a manipulator dynamics modelling were considered. One example with a considerably simplified mass spatial distribution, and another one with a mass distribution corresponding to a real commercial manipulator. The achieved analysis results confirmed that application of the co-simulation technique eases the use of complex models in analysis of manipulator dynamics with use of the general purpose computing environments

Distribution and thickness of the surface contaminations on STM tungsten tips, studied by AES/SEM and ARXPS

The combination of Auger electron spectroscopy (AES), scanning electron microscopy (SEM) and angle resolved X-ray photoelectron spectroscopy (ARXPS) has been applied to the analysis of the distribution of elements at the surface region of electrochemically etched tungsten tips and the determination of the thickness of a layer with oxygen and carbon contamination. Auger line profiling revealed a homogeneous distribution of oxygen and significant enrichment of carbon on the W tip between 0 and 1.5 μm from the top. The thickness of the contamination layer on various W materials, electrochemically etched, was found to be 1.35±0.15 nm as measured using ARXPS, and was estimated to be about 1–3 nm as measured by AES

Design and Fabrication of TiO₂/Lignocellulosic Carbon Materials:Relevance of Low-temperature Sonocrystallization to Photocatalysts Performance

Cafeteria Buildinghttps://egrove.olemiss.edu/phay_uni/1278/thumbnail.jp

Clustering of Staphylococcus aureus bovine mastitis strains from regions of Central-Eastern Poland based on their biochemical and genetic characteristics

Staphylococcus aureus strains were isolated from mastitic milk of cows with infected mammary glands. The animals were living in 12 different farms near Lublin, in Central-Eastern Poland. A biochemical identification method based on enzymatic assay was performed, followed by haemolytic and proteolytic tests. PCR-RFLP targeted on the gap gene allowed the genetic identification of strains at the species level and verified phenotypic identification results. A molecular typing method using triplex PCR was performed to recognize the genetic similarity of the analyzed strains. DNA microarray hybridization (StaphyType, Alere Technologies) was used for detection of antibiotic resistance and virulence associated markers. The results obtained indicate high genetic similarity in strains isolated from the same sites. High genetic similarities were also detected between strains isolated from cows from different farms of the same region. A slightly lower similarity was noted however, in strains from various regions indicating that the strains are herd specific and that the cow's infections caused by S. aureus were of a clonal character. In 21 representative isolates selected for DNA-microarray testing, only fosfomycin (fosB) and penicillin resistance markers (blaZ, blaI, blaR) were detected. The presence of genes coding for haemolysins (lukF, lukS, hlgA, hla, hld, hlb), proteases (aur, sspA, sspB, sspP), enterotoxins (entA, entD, entG, entI, entJ, entM, entN, entO, entR, entU, egc-cluster), adhesins (icaA, icaC, icaD, bbp, clfA, clfB, fib, fnbA, map, vwb) or immune evasion proteins (scn, chp, sak) was common and, with exceptions, matched triplex PCR-defined clusters

Self-reporting molecularly imprinted polymer with the covalently immobilized ferrocene redox probe for selective electrochemical sensing of p-synephrine

Article simultaneously imprinting the p-synephrine 1 template and covalently immobilizing a a ferrocene redox probe in a (bis-bithiophene)-based polymer. The resulting molecularly imprinted polymer (MIP) was deposited on the Pt electrode as a thin film to form a redox self-reporting MIP film-based chemosensor

Indium(II) chloride as a precursor in the synthesis of ternary (Ag–In–S) and quaternary (Ag–In–Zn–S) nanocrystals

A new indium precursor, namely, indium(II) chloride, was tested as a precursor in the synthesis of ternary Ag−In−S and quaternary Ag−In−Zn−S nanocrystals. This new precursor, being in fact a dimer of Cl2In−InCl2 chemical structure, is significantly more reactive than InCl3, typically used in the preparation of these types of nanocrystals. This was evidenced by carrying out comparative syntheses under the same reaction conditions using these two indium precursors in combination with the same silver (AgNO3) and zinc (zinc stearate) precursors. In particular, the use of indium(II) chloride in combination with low concentrations of the zinc precursor yielded spherical-shaped (D = 3.7−6.2 nm) Ag−In−Zn−S nanocrystals, whereas for higher concentrations of this precursor, rodlike nanoparticles (L = 9−10 nm) were obtained. In all cases, the resulting nanocrystals were enriched in indium (In/Ag = 1.5−10.3). Enhanced indium precursor conversion and formation of anisotropic, longitudinal nanoparticles were closely related to the presence of thiocarboxylic acid type of ligands in the reaction mixture. These ligands were generated in situ and subsequently bound to surfacial In(III) cations in the growing nanocrystals. The use of the new precursor of enhanced reactivity facilitated precise tuning of the photoluminescence color of the resulting nanocrystals in the spectral range from ca. 730 to 530 nm with photoluminescence quantum yield (PLQY) varying from 20 to 40%. The fabricated Ag−In−S and Ag−In−Zn−S nanocrystals exhibited the longest, reported to date, photoluminescence lifetimes of ∼9.4 and ∼1.4 μs, respectively. It was also demonstrated for the first time that ternary (Ag−In− S) and quaternary (Ag−In−Zn−S) nanocrystals could be applied as efficient photocatalysts, active under visible light (green) illumination, in the reaction of aldehydes reduction to alcohols