Showing papers by "University of Architecture, Civil Engineering and Geodesy published in 2013"

Enhanced photocatalytic degradation of methylene blue on multiwalled carbon nanotubes–TiO2

Abstract: A visible-light photocatalyst of multiwalled carbon nanotubes decorated with TiO2 nanoparticles (MWCNT/TiO2) was synthesized by a two-step method, in which TiO2 was first mounted on MWCNT surfaces by hydrolysis of tetrabutyl titanate and further crystallized into anatase nanocrystal in a vacuum furnace at 500°C. The photocatalytic degradation of methylene blue over the ultraviolet (UV) and visible-light spectrum regions was investigated. The MWCNT/TiO2 was able to absorb a high amount of photo energy in the visible-light region, driving effectively photochemical degradation reactions. There were more OH radicals produced by the MWCNT/TiO2 (1:3) than by pure TiO2 under UV and visible-light irradiation. In the photodegradation of methylene blue, as a model reaction, a signification enhancement in the reaction rate was observed with the MWCNT/TiO2 (1:3), compared to bare TiO2 and the physical mixture of MWCNTs and TiO2. MWCNTs can improve the photocatalytic activity of TiO2 in two aspects, namely e(-) transportation and adsorption. This work provides new insight into the fabrication of MWCNT/TiO2 as a high performance visible-light photocatalyst and facilitates its application in photocatalytic degradation of organic compounds.

Adsorption of Methyl Orange Dye Onto Multiwalled Carbon Nanotubes

Abstract: The adsorption of methyl orange dye (MO) on multiwalled carbon nanotubes (MWCNTs) from aqueous solutions was investigated in a batch stirred cell. The effects of temperature, stirring speed, MO concentration, MWCNT mass on MO adsorption were investigated. The results showed that the MO adsorption increased with its concentration in the aqueous solutions. MO adsorption also increased with temperature. The MO removal from the solution increased as MWCNT mass increases. The kinetic study demonstrated that MO adsorption on MWCNTs was in a good accordance with the pseudo-second-order kinetic model.

A cell-based smoothed three-node Mindlin plate element (CS-MIN3) for static and free vibration analyses of plates

Abstract: The cell-based strain smoothing technique is combined with the well-known three-node Mindlin plate element (MIN3) to give a so-called the cell-based smoothed MIN3 (CS-MIN3) for static and free vibration analyses of plates. In the process of formulating the system stiffness matrix of the CS-MIN3, each triangular element will be divided into three sub-triangles, and in each sub-triangle, the stabilized MIN3 is used to compute the strains and to avoid the transverse shear locking. Then the strain smoothing technique on whole the triangular element is used to smooth the strains on these three sub-triangles. The numerical examples demonstrated that the CS-MIN3 is free of shear locking, passes the patch test and shows four superior properties such as: (1) be a strong competitor to many existing three-node triangular plate elements in the static analysis, (2) can give high accurate solutions for problems with skew geometries in the static analysis, (3) can give high accurate solutions in free vibration analysis, (4) can provide accurately the values of high frequencies of plates by using only coarse meshes.

Re-analysis of the (100), (001), and (020) rotational structure of SO2 on the basis of high resolution FTIR spectra

Abstract: Three infrared spectra, weak (W), medium (M), and strong (S), of the 32SO2 molecule were recorded with high resolution in the 1000–1500 cm−1 region. Spectra were recorded with the Fourier Transform interferometer Bruker IFS-120 HR in Oulu (Finland) with different pressures, absorption path lengths, and recording time. That allowed us to record not only the ν 1 and ν 3 bands with higher values of quantum numbers J and Ka than it was made earlier, but to record for the first time very weak 2 ν 2 band. In this case, transitions with the values J max . / K a max . equal to 89/37, 109/28, and 54/9 were assigned in the experimental spectra for the bands ν 1 , ν 3 , and 2 ν 2 , respectively. As it became clear in the course of the analysis, the rotational parameters of the ground vibrational state, known in the literature, do not describe suitably the ground state combination differences (GSCD) for the states with the value K a > 26 – 27 . As a consequence, the ground state rotational parameters were improved on the basis of our experimental data. The 12 131 transitions assigned in the experimental spectrum (7618, 3952, and 561 transitions of the bands ν 1 , ν 3 , and 2 ν 2 , respectively) were used for determination of ro-vibrational energy values of the vibrational states (100), (001), and (020). The lasts were used then in the fit procedure together with known in the literature high accurate sub-millimeter wave data. Resonance interactions between all three vibrational states have been taken into account in the Hamiltonian used for the fit. As a result, the 51 varied parameters, obtained from the fit, reproduce 4063 ro-vibrational energies of the states (100), (001), and (020) (12 131 initial experimental transitions) with accuracies close to experimental uncertainties: the rms deviation is 6.1×10−5 cm−1, 9.7×10−5 cm−1, and 13.9×10−5 cm−1 for our FTIR data (for the (100), (001), and (020) states, respectively), and comparable with experimental uncertainties for heterodyne data.

Two photoluminescent metal–organic frameworks based on a BODIPY-derived bipyridine ligand

Abstract: Two new metal–organic open frameworks (MOFs) [Zn3L2(btc)2(H2O)]·(guests) (1), [CdL(bdc)]·(guests) (2), were successfully prepared by using a photoluminescent BODIPY-based bipyridine linker, L, and auxiliary ligands 1,4-benzenedicarboxylate (H2bdc) and 1,3,5-benzenetricarboxylate (H3btc), respectively. MOF 1 has a 2-fold interpenetrating three-dimensional (3D) framework with an 8-connecting body centered cubic (bcu) net, built upon a paddlewheel cluster [Zn2(O2CR)4], a tetrahedrally connecting Zn and a 3-connected btc3− ligand. MOF 2 has a highly open framework with a kagome-type net. It is a pillared layered structure made of 2D [Cd(bdc)] kagome sheets and L as pillars. MOF 1 was shown to exhibit permanent porosity and adsorption of N2, H2, CO2 and CH4. Both MOFs exhibited strong photoluminescent emissions at room temperature with peaks at 540 nm upon excitation, owing to a ligand L-based excited state.

One-step fabrication of high performance micro/nanostructured Fe3S4–C magnetic adsorbent with easy recovery and regeneration properties

Abstract: A magnetic Fe3S4–C composite adsorbent with micro/nanostructure was fabricated by a facile one-step solvothermal method using glucose as carbon source. The prepared products are of a tremella-like micro/nanostructure with magnetic properties and a surface area of 12 m2 g−1. The carbonaceous materials disperse uniformly on the surface of the tremella-like composites. Further experiments have revealed that glucose plays an important role in formation of such structured composites. It not only determines the morphology but also supplies functional groups which act as active sites in the adsorption process. More importantly, the composites can remove contaminants in water with high efficiency and be separated quickly at a low external magnetic field, and can be regenerated after washing with ethanol, showing good recycling performance. This work not only gives a deep insight in to the formation of novel micro/nanostructured magnetic composites but also supplies a new efficient adsorbent for water treatment.

Two approaches for studying the impact response of viscoelastic engineering systems: An overview

Abstract: Two approaches for studying the impact response of viscoelastic engineering structures are considered by the example of the dynamic response of a viscoelastic Bernoulli-Euler beam transversely impacted by an elastic sphere. The Young's modulus of the viscoelastic beam is the time-dependent operator, which is defined either via the Kelvin-Voigt fractional derivative model or via the standard linear solid fractional derivative model. The first approach assumes that Poisson's ratio is not an operator but a constant, while under the second approach the bulk modulus is considered to be constant. The transverse impact of the elastic sphere upon the viscoelastic beam is investigated using both approaches. The comparison of the results obtained shows that the solution obtained at the constant Poisson's ratio is much simpler than that at the constant bulk modulus.

Synthesis and properties of four coordination polymers built from a semi-rigid tripod carboxylic acid

Abstract: By using a semi-rigid multidentate carboxylate linker 4,4′,4′′-(((2,4,6-trimethylbenzene-1,3,5-triyl)tris(methylene))tris(oxy))tribenzoic acid (H3L), four coordination polymers, namely, [Cd3(L)2(H2O)4]·(guest) (1), [Mn3(L)2(DMF)2(H2O)2]·(guest) (2), [Co7(L)4(DMF)6(COOH)2]·(guest) (3), and [Zn3(L)2(DMF)2(H2O)3]·(guest) (4), were obtained and characterized by single-crystal X-ray diffraction, thermogravimetric and photoluminescent studies. Compound 1 is a two-dimensional (2-D) hcb-type layered structure made of rare, interlocked double-layered honeycomb sheets. Compound 2 is a doubly-interpenetrating (3,6)-connected 3-D network, in which L and Mn3 act as triangle and trigonal prismatic nodes, respectively. Compound 3 has a (4,12)-connecting 3-D polycatenated network made of a rare four-ladder 2-D sheet, in which the Co7 cluster is considered as a 12-connecting node and the ligand L3− is a 3-connecting node. Similar to 1, compound 4 also possesses a 2-D hcb-type layered structure, but it is built from two interpenetrating single sheets. Compounds 1 and 4 exhibited strong blue photoluminescent emissions at room temperature upon excitation, owing to a ligand-centered excited state. The emission intensities of the two compounds varied upon contact with different solvents or analytes, exhibiting selective emission quenching responses towards nitroaromatics.

Кластерный механизм реализации жилищной политики региона (Cluster Mechanism of Realization of Housing Policy of the Region)

Abstract: Russian Abstract: Монография посвящена вопросам социально-экономического развития и реализации жилищной политики региона на основе кластерного механизма, структурно формируемого организациями строительного производства, индустрии строительных материалов, развитием жилой недвижимости, финансово-кредитной сферы при поддержке региональных органов властиEnglish Abstract: The monograph is devoted to questions of social and economic development and realization of housing policy of the region on the basis of the cluster mechanism which is structurally formed by the organizations of construction production, the industry of construction materials, development of residential real estate, the financial and credit sphere with support of the regional authorities

Design of plastic diffractive–refractive compact zoom lenses for visible–near-IR spectrum

Abstract: The requirements for selecting the initial scheme for a compact plastic zoom lens are formulated. The main stages of the initial scheme of the transformation, incorporating the diffractive lens and replacement of the lenses’ glasses by optical plastics, are presented. The efficiency of the suggested techniques of the optical layout process are demonstrated by using the example of the design and analysis of a zoom lens intended for use in security cameras for day or night vision.

One-dimensional nonlinear chromatography system and delta-shock waves

Abstract: The Riemann problem for the nonlinear chromatography system is considered. Existence and admissibility of δ-shock type solution in both variables are established for this system. By the interactions of δ-shock wave with elementary waves, the generalized Riemann problem for this system is presented, the global solutions are constructed, and the large time-asymptotic behavior of the solutions are analyzed. Moreover, by studying the limits of the solutions as perturbed parameter \({\varepsilon}\) tends to zero, one can observe that the Riemann solutions are stable for such perturbations of the initial data.

Joint remote preparation of four-qubit cluster-type states with multiparty

Abstract: For N+1-sender independently share the classical knowledge of a quantum state, a new scheme for joint remote preparation of four-particle cluster-type states using only two partially two-particle entangled states as quantum channel is presented. In our scheme, each of the senders is just required to perform a bipartite projective measurement, and the receiver adopts some appropriate unitary operation to obtain the original state with certain probability. We also discuss four type information-splitting methods which can make the receiver obtain the unknown state. The classical communication cost is also calculated.

Removal of radiocobalt from aqueous solution by Mg 2 Al layered double hydroxide

Abstract: The adsorption behavior of radiocobalt by Mg2Al layered double hydroxide (Mg2Al LDH) was studied as a function of contact time, pH, ionic strength, foreign ions, FA and temperature under ambient conditions. The results showed that the kinetic adsorption could be described by a pseudo-second order model very well. The adsorption of Co(II) on Mg2Al LDH was strongly dependent on pH and ionic strength. The presence of FA enhanced the adsorption of Co(II) on Mg2Al LDH at low pH, whereas reduced Co(II) adsorption at high pH. The Langmuir model fitted the adsorption isotherms of Co(II) better than the Freundlich and D–R model at three different temperatures of 303, 323 and 343 K. The thermodynamic parameters (ΔH°, ΔS° and ΔG°) calculated from the temperature dependent adsorption isotherms indicated that the adsorption process of Co(II) on Mg2Al LDH was endothermic and spontaneous. The results show that Mg2Al LDH is a promising material for the preconcentration and separation of pollutants from large volumes of aqueous solutions.