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Mesoporous silica SBA-15 materials of high specific surface area (~700 m2 g−1) were synthesized by using block copolymer Pluronic P123 as template and tetraethoxysilane as silica source. The obtained materials were characterized by XRD, nitrogen adsorption - desorption measurements, SEM, EDS and AFM analysis. It was found that small modifications of synthesis conditions influenced the morphological features of the synthesized SBA-15 samples. The SEM analysis had shown that the SBA-15 synthesized at lower temperature and longer time of reaction (80°C, 48 h) provided elongated rod-shaped grains about 1μm long. The other sample synthesized at higher temperature and shorter time of reaction (100 °C, 24 h) had rounded grains and grains of regular spherical shape with diameters ranging from 0.5 to 2 μm. The EDS analysis confirmed that the particles of both synthesized samples were of the SiO2 content. In addition, the AFM analysis had shown different surface morphologies of the materials synthesized under various conditions. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III-45012, Grant no. III-45005 and Grant no. OI-172045]

Biomorphous β-SiC ceramics were produced from linden wood by impregnation with tetraethyl orthosilicate (TEOS), followed pyrolysis and high temperature treatment at 1580 °C. Six specimen groups included charcoal and five groups with different number of impregnation were analyzed. Flexural and compressional strength of charcoal and woodlike SiC ceramic were characterized using three-point and compression testing. Mechanicall properties increased slightly with number of impregnation cycles. Ultrasonic pulse velocity testing (UPVT) was used to determine dynamic young modulus of elasticity. Laser surface modification was studied by interaction with Nd:YAG laser, operating at 1064 or 532 nm wavelengthss and pulse duration of 150 ps. [ABSTRACT FROM AUTHOR]

Copyright of Revue de Stomatologie & de Chirurgie Maxillo-Faciale is the property of Masson SPA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revue de Stomatologie & de Chirurgie Maxillo-Faciale is the property of Masson SPA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

TiO2 nanopowders were produced by sol-gel technique using TiCl4 as a starting material. For the preparation of crystalline anatase with developed surface area, this aqueous solution has been mixed with 0.05 M or 0.07 M (NH4)2SO4 solution in a temperature-controlled bath. The pH values of the suspension were 7, 8 or 9. According to the x-ray diffraction (XRD) analysis the anatase crystallite sizes were about 12 nm, which coincided with the average particle size revealed by scanning electron microscopy (SEM). The Raman scattering measurements have shown the presence of a small amount of highly disordered brookite phase in addition to dominant anatase phase with similar nanostructure in all synthesized powders. BET measurements revealed that all synthesized catalysts were fully mesoporous, except the sample synthesized with 0.07 M (NH4)2SO4 at pH=9, which had small amount of micropores. The photocatalytic degradation of herbicide Clomazone was carried out for both the pure active substance and as the commercial product (GAMIT 4-EC) under UV irradiation. The best photocatalytic efficiency was obtained for the catalyst with the largest specific surface area, confirming this parameter as crucial for enhanced photocatalytic degradation of the pure active substance and commercial product of herbicide Clomazone. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III45018]

This paper presents a method for recognition of physical exercises, using only a triaxial accelerometer of a smartphone. The smartphone itself is free to move inside subject's pocket. Exercises for leg muscle strengthening from subject's standing position squat, right knee rise and lunge with right leg were analyzed. All exercises were performed with the accelerometric sensor of a smartphone placed in the pocket next to the leg used for exercises. In order to test the proposed recognition method, the knee rise exercise of the opposite leg with the same position of the sensor was randomly selected. Filtering of the raw accelerometric signals was carried out using Butterworth tenth-order low-pass filter. The filtered signals from each of the three axes were described using three signal descriptors. After the descriptors were calculated, a probability density function was constructed for each of the descriptors. The program that implemented the proposed recognition method was executed online within an Android application of the smartphone. Signals from two male and two female subjects were considered as a reference for exercise recognition. The exercise recognition accuracy was 94.22% for three performed exercises, and 85.33% for all four considered exercises.

In this work, a new carbon paste electrode, prepared from nitrogen- -doped hydrothermal carbon (CHTCN) was applied for the electrochemical detection and determination of carbendazim fungicide. CHTCN samples with the nominal nitrogen content 0.05–0.5 wt. % in glucose precursor were prepared by simple, low-cost synthesis with the accompanying carbonization to 1273 K. The presence of nitrogen in CHTCN samples was confirmed by elemental analysis. Characterization of CHTCN as material for carbon paste electrode was achieved by cyclic voltammetry measurement of the Fe(CN)6 3-/4- redox couple. The results showed that best electrochemical response was obtained from the sample with a nominal nitrogen concentration of 0.1 wt. % and with tricresyl phosphate as a binder. During the development of a differential pulse stripping voltammetric method for carbendazim determination applying new electrode, the following experimental parameters were studied: the sort and amount of binding liquid, the effect of pH, accumulation potential and accumulation time. Under optimal conditions, the electrode offered linearity in the wide concentration range from 25 to 490 ng cm-3 and an estimated detection limit of 1.21 ng cm-3. Moreover, the electrode showed good stability, high selectivity and satisfactory anti-interference ability. Finally, the developed method was successfully applied for the determination of carbendazim traces in spiked tap and river water samples. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III 45006]

The prevalence of smartphones and their adequate computer skills can be used for detecting everyday physical exercises. Acquired information on performed exercises can be used in the field of Health Informatics. For identification of particular physical activity a number of sensors and their repositioning during exercises are needed. This paper presents a way to classify the type of exercise using only triaxial built-in accelerometric sensor in the smartphone. The smartphone itself is free to move inside the subject pocket. The problem of using a number of sensors and their repositioning during exercise is solved by raw signal filtering and by defining a set of signal descriptors. Nine characteristic exercises have been analyzed for different programs and levels of exercise. To filter the raw accelerometer signal a low-pass 10-th order Butterworth filter is used. The filtered signals are described in terms of five descriptors which are used to train an artificial neural network (ANN). Classification of the type of exercise is performed using ANN with an error of 0.7%. Some exercises can be performed with only left or right leg. The classification accuracy of proposed approach is tested in a way that the smartphone was always in the subject's right pocket even when the exercise is performed using left leg only.

New approaches in the treatment of esophageal cancer comprise endoscopy with refinements of esophagoscopic intraluminal resection by endoscopic submucosal dissection. Radical open surgery is more and more replaced by minimally invasive esophagectomy (MIO), especially in the hybrid technique with laparoscopic gastrolysis and transthoracic esophageal resection and gastric pull-up. Total MIO also in the robotic technique has not yet shown that it produces superior results than the hybrid technique. Fluorescent dye can improve the intraoperative visualization of the vascularization of the gastric conduit. The individualization of neoadjuvant therapy is the magic word in clinical research of multimodal treatment of esophageal cancer. This means response prediction based on molecular markers or clinical response evaluation. The documentation of the diversity of postoperative complications is now standardized by an international consensus. The value of enhanced recovery after surgery is not yet approved compared to conventional management.

The paper published in the Spring 2014 issue of VOJNO DELO explored the functioning of protection and rescue system at the level of local government (town/municipality). The paper was written on the basis of laws and bylaws that had been published up to January 2013. In the meantime, several more bylaws have been passed which oblige local governments to undertake other additional activities, in order to make the protection and rescue system more complete and more efficient. This paper explores five more bylaws, and thus completes the former paper.

Protection and rescue, as one of the core missions of the civil defense, has its special place in the defense system in the Republic of Serbia. It is carried out on the basis of the adopted laws and bylaws through the established system of protection and rescue of people, protection and safeguarding of material and cultural goods, and environment protection. It is implemented by the civil defense assets, primarily through preventive actions and the implementation of effective measures and activities aimed at preserving protecting and improving the safety of citizens, society and state. The paper deals with the protection and rescue system in the Republic of Serbia through normative and legal regulations, with special emphasis on the place and role of the civil defense assets.

The microstructural characterization and adsorption properties of metakaolin (MK) and alkali-activated metakaolin, known as geopolymer materials (GP) were investigated. The structure and properties of the metakaolin and obtained geopolymer were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. Furthermore, based on the analysis of adsorption efficiency, microstructure and mineral structure, the difference between geopolymer and metakaolin on the performance of immobilizing heavy metals have been discussed. The kinetics of adsorption can be represented by pseudo-second order equation. The results of lead ions adsorption experiments were best fitted by Freundlich adsorption isotherm for both investigated adsorbents. The highest removal efficiencies of alkali-activated material based on metakaolin was found 97.5% at pH 4 and metakaolin removal efficiencies was found 92% at pH 5.5.[Projekat Ministarstva nauke Republike Srbije, br. III 45012 i br. 172007]

The titanium dioxide (TiO2) nanopowders were produced by sol-gel technique from tetrabutyl titanate as a precursor by varying some parameters of the sol-gel synthesis like the temperature (500 and 550 °C) and the duration of the calcination (1.5, 2, and 2.5 h). X-ray powder diffraction (XRPD) results have shown that all synthesized nanopowders are dominantly in anatase phase, with the presence of a small amount of rutile in samples calcined at 550 °C. According to the results obtained by Williamson-Hall method, the anatase crystallite size was increased with the duration of the calcination (from 24 to 29 nm in samples calcined at lower, and from 30 to 35 nm in samples calcined at higher temperature). The analysis of the shift and linewidth of the most intensive anatase Eg Raman mode confirmed the XRPD results. The analysis of pore structure from nitrogen sorption experimental data described all samples as mesoporous, with mean pore diameters in the range of 5-8 nm. Nanopowder properties have been related to the photocatalytic activity, tested in degradation of the textile dye (C.I. Reactive Orange 16), carbofuran and phenol. [Projekat Ministarstva nauke Republike Srbije, br. III45018 i br. ON171032]

This paper analyses the use of equivalent frequency-equivalent time diagram (FT diagram) of partial discharge (PD) pulses, regarding voltage and charge pulses. The described approach is widely used for large generators insulation testing purposes. For sake of clarity the certain types of partial discharge phenomena in insulation of electric machines are described and explained. The contemporary FT analysis of PD pulses is based on equivalent frequency and equivalent pulse time width derived by signal processing techniques and calculations. The numerical simulation derived and experimentally derived results are compared and evaluated for each kind of PD pulses (voltage or charge pulses). Next, the high voltage (HV) device with distributed parameters connected to HV voltage source is simulated. The parameters used in the simulation correspond to one real large synchronous generator. The obtained results lead us to the conclusion that the processing of the strain of PD charge pulses gives much more accurate results than the processing of the strain of PD voltage pulses. The experiment conducted on a large hydro generator confirmed the previous conclusions. At a same time, the sources of recorded results dispersion are shown and explained.

Local governments, in accordance with the Law on Emergency Situations, the Law on Local Self-Government, and other regulations, regulate the operation of the protection and rescue system within the territory of their jurisdiction, defining: the subjects of protection and rescue; responsibilities of the municipality; inclusion of qualified entities and their activation in the system; the role of citizens, associations of citizens and other organizations; coordination and management of protection and rescue in emergency situations; personal, mutual and collective protection; implementation of measures and tasks of civil protection; appointment of commissioners and deputy commissioners; forming of civil protection general purpose units; functioning of the public warning system; installation of sirens; training and preparation; planning and programming; financing of the protection and rescue system; assessment of damages; honors and awards, and other issues important to the organization and functioning of the civil protection. The paper deals with the place and role of local governments in the protection and rescue system, focusing on the organization and preparation of assets and resources for acting in emergency situations.

To produce a new component there are a trial and error stage to obtain a part without defects, which strongly depends on operator's experience. At this stage, the experience of designer and manufacturers should give an important aid to reduce trials to realize the minimization of response time and cost with maximization of the product equality. Rubber pad forming highly improves the formability of the blank because the contact surfaces between the rigid die and the rubber pad is flexible. This method enables to produce sheet metal components with complex contour by relatively low cost because only one rigid die is required. However, in aerospace field, parts are produced in small sheet metal bending and small number of components. It means that it is not worthy for large investments in tools and process design. For these reasons, it is necessary to use FE simulation of manufacturing process during the conceptual design.

Introduction: Sentinel lymph node biopsy is a standard staging procedure in patients with early breast cancer. Aim of the study is a validation procedure of sentinel lymph node biopsy (SLNB) in our institution and comparison between two mapping techniques - isotope mapping and methylene blue dye for lymphatic mapping. Material and methods: The study comprised 75 women with breast cancer of clinical stage T1-2N0M0. We analyzed patients from June, 2010 to March, 2013. In 39 patients, (Group A) lymphatic mapping technique was performed by using the peritumoral injection of 37MBq activity isotope (99m Technetium NANOCIS),and in 36 patients (Group B) mapping technique was performed by using the periareolar injection of 2-4 ml blue dye (Methylene blue 1%). Axillary dissection was performed in both groups after SLNB. Results: Out of 75 patients, sentinel lymph node was identified in 68 (90.7%). Identification rate was similar between the groups - 89.7% (Group A), 91.7% (Group B). Accuracy rate was 97% between the groups, that is, Group A 97.1% and Group B 96.9%. In relation to the Group A (90.6%), sensitivity rate was slightly higher in the Group B - 91.6%,. False negative rate of SLNB was higher in the Group A (9.1%) in relation to the Group B (8.3%). The average number of sentinel nodes detected in both groups was 1.2. Conclusion: The results of the study confirmed and validated both methods of lymphatic mapping techniques in SLNB. There were no significant statistical differences (p>0.05) in accuracy, sensitivity and false negative rate between these two groups.

Early diagnosis of faults that might occur in industrial processes makes it possible to perform important preventative actions and therefore avoid the heavy economic losses involved in production stoppages and the replacement of elements and parts. The main idea of detecting shorted turns on rotor poles in hydrogenerators using artificial neural networks is to generate signals that reflect inconsistencies between nominal and faulty system operating conditions. Two types of nonlinear autoregressive networks with exogenous inputs (NARX) are used. In both cases one can successfully detect shorted turns on rotor poles.

Resorcinol-formaldehyde carbon cryogel has been prepared, characterized and used for the removal of commonly used herbicide clopyralid from the aqueous solutions under varying experimental conditions. Carbon has shown a relatively high specific surface area, significant mesoporosity and an amorphous structure. A set of the following isotherm models has been used to interpret the equilibrium data: Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, Jovanović, Hurkins-Jura, and Helsey model. Several models have fitted well although the calculated values for qmax poorly correlate with the data obtained experimentally. The kinetic models of the pseudo-first and pseudo-second-order, the models of Elovich, Bangham and the intraparticle diffusion model have been used for fitting the kinetic data. The rate of the process is fast in the beginning while adsorption equilibrium is attained not until 24 hours. Adsorption was found to be pH dependent and favored in acidic solutions.

Nowadays robotic surgery is established for abdominal and thoracic surgery. It has been shown that complex procedures are feasible using robotic systems, e.g., da Vinci Xi , with a huge benefit in precision. Different techniques for esophageal cancer surgery are reported; however, only a few robotic and partial robotic procedures are described. Therefore, a fully robotic (abdominal and thoracic) Ivor Lewis esophageal resection using four robotic arms—RAMIE4—the standard technique used for lower esophageal cancer, is presented in this paper. The technique shown in the video was performed successfully in 100 cases in 24 months. The reconstruction is performed with a gastric conduit pull-up and intrathoracic manually inserted 28-mm circular end-to-side stapled anastomosis. This video demonstrates the feasibility of RAMIE4 in the abdomen and thorax and reveals advantages of the robotic assistance. [ABSTRACT FROM AUTHOR]

This paper presents methodology for development of software application for integration of process planning, scheduling, and the mobile robot navigation in manufacturing environment. Proposed methodology is based on the Russian Theory of Inventive Problem Solving (TRIZ) and multiagent system (MAS). Contradiction matrix and inventive principles are proved as effective TRIZ tool to solve contradictions during conceptual phase of software development. The proposed MAS architecture consists of six intelligent agents: job agent, machine agent, optimization agent, path planning agent, machine learning agent and mobile robot agent. All agents work together to perform process plans optimization, schedule plans optimization, optimal path that mobile robot follows and classification of objects in a manufacturing environment. Experimental results show that developed software can be used for proposed integration in order to improve performance of intelligent manufacturing systems.

The Ru-doped SnO2 powder, (RuxSn1-x)O2, with the Sn:Ru atomic ratio of 9:1 was synthesized and used as a support for Pt nanoparticles (30 mass% loading). The (RuxSn1-x)O2 support and Pt/(RuxSn1-x)O2 catalyst were characterized by X-ray diffraction, energy dispersive X-ray spectroscopy and transmission electron microscopy (TEM). (RuxSn1-x)O2 was found to be two-phase material consisting of probably solid solution of RuO2 in SnO2 and pure RuO2. The average Pt particle size determined by TEM was 5.3 nm. Cyclic voltammetry of Pt/(RuxSn1-x)O2 indicated good conductivity of the sup-port and displayed usual features of Pt. The results of the electrochemical oxidation of COads and methanol on Pt/(RuxSn1-x)O2 were compared with those on commercial Pt/C and PtRu/C catalysts. Oxidation of COads on Pt/(RuxSn1-x)O2 starts at less positive potentials than on PtRu/C and Pt/C. Potentiodynamic polarization curves and chronoamperometric curves of methanol oxidation indicated higher initial activity of Pt/(RuxSn1-x)O2 catalyst compared to PtRu/C, but also a greater loss in the current density over time. Potentiodynamic stability test of the catalysts revealed that deactivation of the Pt/(RuxSn1-x)O2 and Pt/C was primarily caused by the poisoning of Pt surface by the methanol oxidation residues, which mostly occurred during the first potential cycle. In the case of PtRu/C the poisoning of the surface was minor and deactivation was caused by the PtRu surface area loss. [Projekat Ministarstva nauke Republike Srbije, br. ON-172054]

The capacity of carbon monolith for pesticide removal from water, and the mechanism of pesticide interaction with carbon surface were examined. Different carbon monolith samples were obtained by varying the carbonization and activation parameters. In order to examine the role of surface oxygen groups in pesticide adsorption, carbon monolith surface was functionalized by chemical treatment in HNO3, H2O2 and KOH. The surface properties of the obtained samples were investigated by BET surface area, pore size distribution and temperature-programmed desorption. Adsorption of pesticides from aqueous solution onto activated carbon monolith samples was studied by using five pesticides belonging to different chemical groups (acetamiprid, dimethoate, nicosulfuron, carbofuran and atrazine). Presented results show that higher temperature of carbonization and the amount of activating agent allow obtaining microporous carbon monolith with higher amount of surface functional groups. Adsorption properties of the activated carbon monolith were more readily affected by the amount of the surface functional groups than by specific surface area. Results obtained by carbon monolith functionalisation showed that π-π interactions were the main force for adsorption of pesticides with aromatic structure, while acidic groups play an important role in adsorption of pesticides with no aromatic ring in the chemical structure.

Tungsten carbide was synthesized by calcination of carbon cryogel with embedded tungsten in a form of metatungstate. This material was used as a support for Pt nanoparticles. XRD pattern of W-C support indicates the presence of WC, W2C, and unreacted W, as well as graphitized carbon. According to the previous TEM analysis of W-C support, it contains particles with core-shell structure, where W particle was covered with the shell of a mixture of WC and W2C. The average Pt grain size calculated from XRD pattern was about 6 nm. Cyclic voltammogram of W-C support was recorded within potential range relevant for its application as a catalyst support in fuel cells. Pair of anodic/cathodic peaks close to the negative potential limit could be ascribed to the intercalation of hydrogen within hydrous tungsten oxide, which is always present on the surface of WC in aqueous solutions. Cyclic voltammogram of Pt/W-C indicated that tungsten oxide species are present on tungsten carbide shell as well as on the surface of Pt nanoparticles. Pt surface is only partially covered by hydrous tungsten oxide. Hydrogen intercalation in hydrous tungsten oxide is enhanced in the presence of Pt nanoparticles. Also, the presence of hydrated tungsten oxide leads to the decrease of OH chemisorbed on Pt surface. Stripping of underpotentially deposited copper was used for the assessment of Pt surface area and the specific surface area of Pt was estimated to 41 m2 g-1. Electrochemical oxygen reduction reaction was examined on the synthesized Pt/W-C catalyst and compared with the results on the commercial Pt/C catalyst. It was found that the current densities at Pt/W-C are almost double as those on Pt/C. The Tafel plots for both catalysts are characterized with two Tafel slopes: -0.060 V dec-1 at low current densities, and -0.120 V dec-1 at high current densities. From the rotational dependence of the reaction rate, it was found that oxygen reduction on both Pt/W-C and Pt/C follows the first order kinetics with respect to O2 and that four electrons are transferred per O2 molecule. The results show that the presence of tungsten carbide in support material i.e. hydrous tungsten oxide on Pt surface, leads to promotion of oxygen reduction on the Pt/W-C catalyst. It was assumed that oxophilic hydrated tungsten oxide hinders OH adsorption on Pt surface, thus increasing Pt surface area available for O2 adsorption and its electrochemical reduction.

This paper suggests the possibility of diagnosing different types of failure in working induction motors using a device for spectral analysis of axial leakage flux, which has been developed by the Electrotechnical Institute Nikola Tesla. A search coil, which can be of different diameters, was mounted concentrically on the shaft at the rear of the motor. The electromotive force (emf) on each of the coils, created as a result of weak magnetic field changes, has a low amplitude. Following the necessary amplifications and adjustments, the signal is digitised on acquisition. In the fast Fourier transform (FFT) stage, the sampled and quantised digital time-based signal is converted to a frequency spectrum. Changes in spectral content are used to identify developing faults.

This paper presents the authors' efforts to conceptual design of control system that can learn from its own experience. The ability of adaptive behaviour regarding the given task in real, unpredictable conditions is one of the main demands for every intelligent robotic system. To solve this problem, the authors suggest a learning approach that combines empirical control strategy, reinforcement learning and axiomatic design theory. The proposed concept uses best features of mentioned theoretical approaches to produce optimal action in the current state of the mobile robot. In this paper empirical control theory imparts the basis of conceptual solution for the navigation problem of mobile robot. Reinforcement learning enables the mechanisms that memorize and update environment responses, and combining with the empirical control theory determines best possible action according to the present circumstances. Axiomatic design theory accurately defines the problem and possible solution for the given task in terms of the elements defined by two previously mentioned approaches. Part of the proposed algorithm was implemented on the LEGO Mindstorms NXT mobile robot for the navigation task in an unknown manufacturing environment. Experimental results have shown good perspective for development of efficient and adaptable control system, which could lead to autonomous mobile robot behaviour.

This article discusses the historical and geographical characteristics of medieval Bosnia, its area and position presented in the perception of Byzantine and post-Byzantine sources. It is characteristic that all these sources, regardless of whether they originated in the 10th, 12th, or 15th century or in the centuries after the collapse of the Byzantine Empire offered testimony of the territory of Bosnia. The presentations are sometimes a bit distorted and unrealistic, and their names are based on ancient standards. Data provided by the source material speaking of the appearance of Bosnia and medieval towns in its territory, were named differently in Byzantine sources.

Shorted turns are the result of failed insulation between individual windings in generator rotors. The use of air-gap magnetic flux probes has proven effective in the detection of generator rotor winding shorted turns. Analysis of air-gap flux probe data can determine the number and location of shorted turns. Here are presented some results of measurements in power plants. Finally, guidelines are given for the installation of magnetic monitoring in practice.

Bentonite samples from Petrovac and Aleksinac were treated with sulfuric acid of different molarities. Differences in structure and texture of the initial and modified bentonite were determined by chemical analysis and Xraypowder diffraction (XRPD), infra-red spectroscopy (FTIR), scanning electron microscopy (SEM) and physisorption nitrogen at −196°C. Sulfuric acid caused an exchange of Al3+, Fe3+ and Mg2+ with H+ ions which led to a modification of the smectite crystalline structure. The Mg and Fe substitution in the octahedral sheet promoted the dispersion of those layers and forming of amorphous silicon. The sequence according to which the cations left the octahedral sheets was as follows: Mg2+>Fe3+>Al3+. The sulfuric acid activated bentonites exhibiting a lower cation exchange capacity (CEC) and а change of specific surface area (SBET) from 6 to 387 for bentonite from Petrovac and from 44 to 1784 m2 g-1 for bentonite from Aleksinac, positioning them as an excellent absorber in wine technology and in the protection of soil and environment.

Introduction. Congenital cholesteatoma of the middle ear is un uncommon and yet not well-defined disease. Only few cases of cholesteatoma in the fossa ovalis with unusual clinical presentation have been reported in medical literature. Case report. We reported a 16-year-old girl with congenital cholesteatoma in the fossa ovalis with minimal clinical presentation. A small mass was found occluding the fossa ovalis and mimicking otosclerotic process within tympanic cavity. The operation started as stapedotomy, and when the process was confirmed it converted to mastoidectomy via the retroauricular approach. Conclusion. The diagnosis of congenital cholesteatoma in children should always be considered, even if the clinical symptoms imitate other ear disorders, in our case otosclerosis. [Projekat Ministarstva nauke Republike Srbije, br. 179055: Cochlear implantation impact on education of deaf and hearing-impaired]

China and the European Union are very interested in developing their mutual relations. They strengthen their positions in the world business by their co-ordinated acting. In their mutual relations, they apply Geoeconomics’ methods. They do not regard each other as a military threat but as one of the main economic partners. Their economies are highly complementary. “The common economic interests“ have a decisive role in China EU policy and EU China policy, respectively. EU is China’s largest economic partner. It is its largest export market, the largest source of new technologies and equipment and one of the largest sources for foreign investments. China is the second important source of industrial products import to EU and the fastest growing export market for EU. The EU enlargement to the East both favourably and unfavourably affects China’s interests. The main cause of friction in China-EU relations is a high Chinese surplus in their mutual trade, high competitiveness of Chinese products on the EU market and China’s pursuit of energy sources in the parts of the world that Western countries, including the leading EU member states, regard as traditionally “forbidden“ such as the Middle East and Africa. China and EU have created mechanisms to settle conflicts of interest in their mutual trade through dialogue.

Activated carbon cloth dressing is an appropriate wound healing material due to its biocompatibility and adsorption characteristics. The influence of gamma radiation as a sterilization process on the adsorption and mechanical properties of activated carbon cloth was investigated. The specific surface area, micropore volume, pore size distribution, surface chemistry as well as the breaking load of activated carbon cloth before and after gamma radiation were examined. Characterization by nitrogen adsorption showed that the activated carbon cloth was a microporous material with a high specific surface area and micropores smaller than 1 nm. Gamma radiation decreased the specific surface area and micropore volume but increased the pore width. The sterilization process changed the surface chemistry quantitatively, but not qualitatively. In addition, the breaking load decreased but without any influence considering the further application of this material.

Fractal analysis was used in previous authors' researches for characterizations of grinded ceramics surface textures by surface profile fractal dimension. In this paper the 'skyscrapers' method was chosen for calculating fractal dimension of surface, using the image processing toolbox, as well as a custom-developed algorithm of Matlab environment. This method entails recording the surface as an image, by using a scanning probe microscope. In the given contact lens case, fractal dimension values confirm changes of the surface roughness during the cleaning and wearing processes. Examination of real surface roughness could provide comparison and functional behavior prediction.

The temperature dependence of oxygen reduction reaction (ORR) was studied on highly dispersed Pt nanoparticles supported on a carbon cryo-gel. The specific surface area of the support was 517 m2 g-1, the Pt particles diameter was about 2.7 nm and the loading of the catalyst was 20 wt.%. The kinetics of the ORR at the Pt/C electrode was examined in 0.50 mol dm-3 HClO4 solution in the temperature range from 274 to 318 K. At all temperatures, two distinct E-log j regions were observed; at low current densities with a slope of -2.3RT/F and at high current densities with a slope of -2.3´2RT/F. In order to confirm the mechanism of oxygen reduction previously suggested at a polycrystalline Pt and a Pt/Ebonex nanostructured electrode, the apparent enthalpies of activation at selected potentials vs. the reversible hydrogen electrode were calculated in both current density regions. Although ∆H ≠a,1 > ∆H ≠a,h , it was a,1 a, h found that the enthalpies of activation at the zero Galvani potential difference were the same and hence it could be concluded that the rate-determining step of the ORR was the same in both current density regions. The synthesized Pt/C catalyst showed a small enhancement in the catalytic activity for ORR in comparison to the polycrystalline Pt, but no change in the mechanism of the reaction.

Coniferous wood (fir) was transformed by pyrolysis into carbon preforms, which were subsequently converted into biomorphic ceramics by the pressure infiltration technique with colloidal silica. An in situ reaction between the silica and the carbon template occurred in the cellular wall at a high sintering temperature. Depending on the employed atmosphere, non-oxide (SiC) or oxide (SiO2) ceramics were obtained. The morphology of the resulting porous ceramics and their phase composition were investigated by scanning electron microscopy (SEM/EDX) and X-ray diffraction (XRD). The experimental results showed that the biomorphic cellular morphology of the wood maintained in both the SiC and silica ceramics, which consisted of only the b-SiC phase and SiO2, respectively. .

The electrochemical characteristics of a mixture of Pt-black and WC powders and its catalytic activity for methanol and formic acid oxidation were investigated in acid solution. XRD and AFM measurements revealed that the WC powder employed for the investigation was a single-phase material consisting of crystallites/spherical particles of average size of about 50 nm, which were agglomerated into much larger particles. Cyclic voltammetry showed that the WC underwent electrochemical oxidation, producing tungstate species. In the case of the mixed Pt + WC powders, the tungstate species were deposited on the Pt as a thin film of hydrous tungsten oxide. Enhanced hydrogen intercalation in the hydrous tungsten oxide was observed and it was proposed to be promoted in mixed powders by the presence of hydrogen adatoms on bare Pt sites. The determination of Pt surface area in the Pt + WC layer by stripping of underpotentially deposited Cu revealed that the entire Pt surface was accessible for underpotential deposition of Cu. Investigation of the electrochemical oxidation of methanol and formic acid on Pt + WC and pure Pt layers did not indicate electrocatalytic promotion due to the presence of WC.

Chronic suppurative otitis media is among the most frequent illnesses treated in ENT wards. To establish the diagnosis, otomicroscopy alone usually suffice. Assessing the sense of hearing, often the sense of balance, too, is mandatory. Assessment of hearing will show the extent of conductive and sensorineural hearing loss. Apart from this, sometimes, when the finding is not obvious, it is necessary to conduct audiological investigation in more detail in order to establish whether the diagnosis of chronic suppurative otitis media is correct. Existence and extent of conductive hearing loss or confIrmation of tympanic membrane perforation by tympanometry can help a great deal. Also, some new results about the site of perforation and the middle ear volume influence on conductive hearing loss may help have a better insight into chronic suppurative otitis media. Assessing the sense of balance may show dysfunctions with not yet necessarily permanent damage: perilymphatic fistula and benign paroxysmal positional vertigo (BPPV). Unilateral or bilateral damage may be diagnosed with appropriate tests of vestibuloocular reflex (VOR): spontaneous nystagmus, head impulse test, head shaking test. These bedside tests do not require bulky, expensive equipment for stimulus delivery or special equipment for recording nystagmus. In addition, their significance is their ability to provide enough information without performing caloric testing which is contraindicated in chronic suppurative otitis media.

The oxygen reduction reaction was investigated in 0.1 M NaOH solution, on a porous coated electrode formed of Pt particles supported on carbon cryogel. The Pt/C catalyst was characterized by the X-ray diffraction (XRD), transmission electron microscopy (TEM) and cyclic voltammetry techniques. The results demonstrated a successful reduction of Pt to metallic form and homogenous Pt particle size distribution with a mean particle size of about 2.7 nm. The ORR kinetics was investigated by linear sweep polarization at a rotating disc electrode. The results showed the existence of two E - log j regions, usually referred to polycrystalline Pt in acid and alkaline solution. At low current densities (lcd), the Tafel slope was found to be close to -2.3RT/F, while at high current densities (hcd) it was found to be close to -2×2.3RT/F. It is proposed that the main path in the ORR mechanism on Pt particles was the direct four-electron process, with the transfer of the first electron as the rate determining step. If the activities are expressed through the specific current densities, a small enhancement of the catalytic activity for Pt/C was observed compared to that of polycrystalline Pt. The effect of the Pt particle size on the electrocatalysis of oxygen reduction was ascribed to the predominant (111) facets of the platinum crystallites. .

A carbon cryogel, synthesized by carbonization of a resorcinol/formaldehyde cryogel and oxidized in nitric acid, was used as catalyst support for Pt nanoparticles. The Pt/C catalyst was prepared by a modified polyol synthesis method in an ethylene glycol (EG) solution. Characterization by nitrogen adsorption showed that the carbon cryogel support and the Pt/C catalyst were mesoporous materials with high specific surface areas (Sbet>400 m2 g-1) and large mesoporous volumes. X-Ray diffraction of the catalyst demonstrated the successful reduction of the Pt precursor to metallic form. TEM Images of the Pt/C catalyst and Pt particle size distribution showed that the mean Pt particle size was about 3.3 nm. Cyclic voltammetry (CV) experiments at various scan rates (from 2 to 200 mV s-1) were performed in 0.5 mol dm-3 HClO4 solution. The large capacitance of the oxidized carbon cryogel electrode, which arises from a combination of the double-layer capacitance and pseudocapacitance, associated with the participation of surface redox-type reactions was demonstrated. For the oxidized carbon cryogel, the total specific capacitance determined by 1/C vs. v0.5 extrapolation method was found to be 386 F g-1. The hydrogen oxidation reaction at the investigated Pt/C catalyst proceeded as an electrochemically reversible, two-electron direct discharge reaction. .