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Models for restrained strains and self-stresses estimation based on the concepts of the conservation law of chemical energy and initial strains calculation in the expansive concrete members are considered, together with their advantages and disadvantages. A modified strains development model (MSDM) is proposed, based on the initial strains calculation approach and extended by taking into account cumulative force induced by the reinforcement as an additional restraint for development of expansion strains. Validity of the proposed MSDM is confirmed by experimental results obtained from tests on uniaxially symmetrically reinforced high expansion energy capacity concrete members. [ABSTRACT FROM AUTHOR]

Background In our proposed model, family members' perceptions of service quality in organisations improve communication about self-determination. In turn, family perceptions of communication openness have a positive relationship with self-determination attitudes of family members. Finally, these attitudes predict self-determination behaviours of individuals with intellectual disability, as reported by family members. Method We tested this model with a sample of 625 family members (196 using 'day care services' and 429 using 'occupational services'). Results Multi-sample structural equation modelling ( SEM) supported the model. Communication and attitudes fully mediated the link from service quality to self-determination behaviours. Conclusions Improving family members' perceptions of service quality and opening channels of communication between professionals and family members are useful strategies to facilitate parents' positive attitudes and increase the frequency of self-determination behaviours at home. [ABSTRACT FROM AUTHOR]

A heating of graphite oxide in concentrated sulfuric acid results in partial removal of oxygen and formation of polyatomic vacancy defects in graphene layers. The boundaries of the defects are decorated by oxygen-containing groups, the number of which can be significantly reduced with the sample annealing in an inert atmosphere. It is shown that initial and annealed perforated graphite (PG) samples interact with gaseous thionylchloride at room temperature. X-ray photoelectron and near-edge X-ray absorption fine structure spectroscopy find negatively charged chlorine and covalently bonded chlorine in the initial PG and only the latter chlorine form in the annealed PG. According to the reference data and our quantum-chemical calculations, graphene donates charge to the adsorbed chlorine atoms, while covalent chlorine bonding occurs at vacancy edges. Two chemical states of chlorine detected by XPS in perforated graphene after exposure to SOCl2. [ABSTRACT FROM AUTHOR]

Two few-layer graphene materials, strongly distinguished in structure, were compared as electrode materials for supercapacitor. The stacks of flat sheets with basal size of a few microns have been obtained as the result of ultrasonication of bromine intercalated graphite dispersion. The highly crumpled large-size layers have been produced by rapid heating of bromine intercalated graphite fluoride. The average number of layers and in-plane crystalline size in the materials were evaluated from Raman spectroscopy. The functional composition was studied using X-ray photoelectron and Infrared spectroscopy. Electrochemical testing of the graphene materials detected re-stacking of thin crumpled layers during the electrode preparation. Furthermore, graphene material produced from the fluorinated graphite showed poor wettability. The mild oxidation of the material in a mixture of sulfuric and nitric acids allowed increasing the capacitance in several times. [ABSTRACT FROM AUTHOR]

The heating of graphite oxide in concentrated sulfuric acid results in partial removal of oxygen and formation of holes with a size of ∼2 nm. The Raman scattering shows that the distance between the holes decreases with the time of processing while the temperature of the acid has no crucial effect on the defectiveness of a graphene layer. The functional composition of the reduced graphite oxide samples is studied by IR and X-ray photoelectron spectroscopy. From the spectral analyses the longer the treatment, the larger the amount of oxygen removed from the graphite oxide. It is found that the edges of the holes are decorated with hydroxyl, carbonyl, and carboxyl groups and hydrogen. An increase in the temperature promotes formation of carboxyl groups. The influence of oxygenated groups and holes on the supercapacitor performance of reduced graphite oxide samples is checked using cyclic voltammetry measurements in an acidic electrolyte. Specific capacitance of samples depending on temperature and time of graphite oxide treatment by concentrated H2SO4. The scan rate of the potential was 5 mV s−1. [ABSTRACT FROM AUTHOR]

Dear Editors: We in the executive committee often receive requests for exemptions from local taxes and levies, particularly for exemptions from payment of land rent. Would you explain in the pages of the journal the procedure for imposing local taxes and levies on citizens, as well as who is entitled to reductions or exemptions and what bodies have the right to decide this. [ABSTRACT FROM AUTHOR]

Nanocomposites based on PtPd nanoparticles with chemical ordering like disordered solid solution on surface of multilayer graphene have been prepared through thermal shock of mechanically obtained mixture of double complex salt [Pd(NH)][PtCl] and different carbon materials-exfoliated graphite, graphite oxide and graphite fluoride. An effect of original carbon precursors on formation of PtPd bimetallic nanoparticles was studied using X-ray absorption spectroscopy (XAFS), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). It was shown that the distribution of bimetallic nanoparticles over the multilayer graphene surface as well as the particles size distribution is controlled by the graphene precursors. For all nanocomposites, the surface of the nanoparticles was found to be Pd-enriched. In case when the thermal exfoliated graphite and graphite oxide were used as the graphene precursors a thin graphitized layer covered the nanoparticles surface. Such a graphitized layer was not observed in the nanocomposite, which used the fluorinated graphite as the precursor. [ABSTRACT FROM AUTHOR]

Perforation of graphite is carried out by treating the graphite oxide with a boiling mineral acid H2SO4 or H3PO4. High-resolution transmission electron microscopy shows formation of a large number of vacancy defects (holes) in the graphene sheets, which are caused more likely by the CO2 liberation during the reduction process. The characteristic size of the holes is about 2 nm. The obtained materials are comparatively examined by X-ray diffraction, Raman and IR-absorption spectroscopy, X-ray photoelectron and near-edge X-ray absorption fine structure spectroscopy. It is found that the products obtained using a strong acid H2SO4 and a weak acid H3PO4 are different in the concentration and electronic state of oxygen and the mean distance between defects. [ABSTRACT FROM AUTHOR]

Fluorinated graphite intercalation compounds (FGICs) with acetonitrile C2F x · yCH3CN ( x = 0.92, 0.69, and 0.49) have been synthesized using a gaseous mixture of BrF3 and Br2 at room temperature and subsequent replacement of the reaction medium components on acetonitrile by isopiestic method. The change in functional composition and electronic structure of FGICs under annealing at 250-260 °C was studied by infrared, X-ray photoelectron, and near-edge X-ray absorption fine structure spectroscopy (NEXAFS) methods. Analysis of the data revealed interaction of acetonitrile with a C2F x matrix. The X-ray spectra detected formation of new nitrogen species attributed to two-coordinated and mono hydrogenated three-coordinated atoms. Mechanism of nitrogen incorporation in the fluorinated graphene layers was proposed. Schematic structure of graphite fluoride C2F x intercalated with acetonitrile and NEXAFS N K-edge spectrum of C2F0.69 · 0.137CH3CN before and after annealing at 250 °C. [ABSTRACT FROM AUTHOR]

A method to obtain previously unknown layered structure composed of stacks of perforated graphene sheets is developed. The method consists in the thermal decomposition of graphite oxide in the concentrated HSO and HPO medium. In order to confirm the presence of holes in graphene layers, a large set of chemical and physicochemical analysis methods are applied. Based on a new matrix, treated thermally and chemically, layered compounds are obtained: oxide, fluoride, and fluoroxide of two types. The obtained compounds are analyzed by transmission electron microscopy, infrared absorption spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, and powder X-ray diffraction. [ABSTRACT FROM AUTHOR]