REINFORCEMENT OF LAMINATED GLASS FACADES AGAINST THE BLAST LOAD

The first defensive element of the building against the explosion is the façade. On the condition that façade is not resistant against explosion and encounters the damage, the blast wave will enter the construction and increases financial losses and casualties. With respect to that glass facades do not possess adequate strength under the explosion; the major aim of the study is to examine variety of the reinforcement practices of glazing facades with the laminated glass subjected to the blast wave. The investigation has been done by two descriptive and simulation approaches with the finite element software of AutoDyn and eight simulations has been represented in the subject of laminated glasses. In addition, through AHP method, related questionnaires were designed so that some experts including 31 people possessing the activity and investigation background of two to thirty years in the civil protection scope answered them. Considered indexes in AHP model consist of resistance against explosion, passed light rate, expenditure, complexity and difficulty of accomplishment so that in the resistance part versus explosion, the results of numerical simulation have been benefited. Outcomes demonstrate the best function in laminated glass models belongs to the overlapped louvered opening model. Afterwards, the model of two-layer laminated glass with the spring is laid. Furthermore, the most economical model which supplies the most light as well as the most safety is the model of one-layer laminated glass with spring.

Impedance Spectroscopy in Ni0.3Zn0.7Fe2O4

Impedance spectroscopies were used to investigate the electrical properties of spinel Ni0.3Zn0.7Fe2O4(NZF) ceramics. Measurement was done using NOVO Dielectric Spectrometer from frequency 0.01 Hz to 3 x 106Hz at temperature 30°C to 200°C. Resistivity response phenomena had been observed in sample sintered at 1100°C and carriers involved are mainly due to electron hopping mechanism between n-type and p-type carriers. The high and low response of grain and grain boundary regions were determined by plotting imaginary part versus real part of resistivity. An equivalent RC circuit of the experimental result had been constructed using a model that had been proposed by Hill and Pickup (1985). The model consists of parallel combination of 2 Havriliak-Negami (1966) model, resistivity and dielectric constant where ρ = 5.79 x 106Ωm and ε = 4.45. It is found that 0.40 ± 0.01 eV, 0.14 ± 0.01 eV and 0.13 ± 0.01 eV and 0.38 ± 0.01 eV (extrinsic region) and 0.50 ± 0.01 eV (intrinsic region) for ac and dc activation energy respectively by using Arrhenius plot.

Differences between the QBO in the first and in the second half of the ERA-40 reanalysis

The representation of the quasi-biennial oscillation (QBO) is investigated in the ERA-40 reanalysis. In the lower stratosphere, where there are a reasonable number of observations, the representation of the QBO is equally good throughout the record. However, strong differences between the first and the second half of the zonal wind data set are found in the upper stratosphere, with a typical offset of –10 m/s in the equatorial zonal wind in the earlier part versus the later part of the ERA-40 record. At the same time, the strength of the QBO is similar. The 7-year running means of zonal wind, wind shear and temperature reveal interesting structures with major changes occuring in the beginning and the middle of the 1980s. Possible explanations are discussed. The identified change of the reanalysed wind profiles over time in ERA-40 demands for a careful use of equatorial upper stratospheric winds from the reanalysis e.g.~for model validation purposes.

Differences between the QBO in the first and in the second half of the ERA-40 reanalysis

The representation of the quasi-biennial oscillation (QBO) is investigated in the ERA-40 reanalysis. In the lower stratosphere, where there is a good number of observations, the representation of the QBO is equally well throughout the record. However, strong differences between the first and the second half of the zonal wind data set are found in the upper stratosphere, with a typical offset of −10 m/s in the equatorial zonal wind in the earlier part versus the later part of the ERA-40 data set. The strength of the QBO is also affected. Possible explanations are discussed. The identified change of the assimilated wind profiles over time in ERA-40 requires a careful use of equatorial upper stratospheric winds from the reanalysis for validation purposes.