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Many buildings in the present scenario have irregular configurations both in plan and elevation. This in future may subject to devastating earthquakes. In case, it is necessary to identify the performance of the structures to withstand against disaster for both new and existing one. The present paper made an attempt to study two kinds of irregularities in the building models namely plan irregularity with geometric and diaphragm discontinuity and vertical irregularity with setback and sloping ground. These irregularities are created as per clause 7.1 of IS 1893 (part1)2002 code. In Oder to identify the most vulnerable building among the models considered, the various analytical approaches are performed to identify the seismic demands in both linear and nonlinear way. It is also examined the effect of three different lateral load patterns on the performance of various irregular buildings in pushover analysis. This study creates awareness about seismic vulnerability concept on practicing engineers.

Defects in low-bandgap polymer based photodetectors play a critical role in determining switching characteristics in the near infra-red spectral-regime relevant to communication wavelength. We carry out detailed studies of the bandwidth limiting factors of the long-live transient photocurrent at different incident wavelength as a function of temperature, light pulse width, bias voltage. The results indicate that dominant transport mechanism of the photogenerated carriers is limited by recombination at low temperature and detrapping rate at high temperature. A general trend of a slower response of photocarriers originating from the band-tail region is observed., 6 pages, 5 figures

We report for the first time a large photoresponse in an array of charge transfer complex Cu:TCNQ nanowires (average diameter 30 nm) fabricated as a nanobridge device. The device shows highest photoresponse for excitation with 405 nm light which matches with its absorption peak. The current gain at zero bias can reach ~104 with an illumination power density of 2x106 W/m2. The zero bias responsivity is ~0.3 mA/W which increases on applying bias reaching 1.0 A/W or more for a bias of 2.0 Volt. Dark and illuminated I-V data are analyzed by two back-to-back Schottky diodes model, which shows the predominant photocurrent in the device arising from the photoconductive response of the nanowires., 4 figures

We report for the first time large photoresponse in a single NW of the charge transfer complex Cu:TCNQ. We fabricate a metal-semiconductor-metal device with a single NW and focus ion beam deposited Pt. We observe large photocurrent even at zero bias. The spectral dependence of the photoresponse follows the main absorption at ~ 405 nm which has the primarily responsible for photogenerated carriers. We have quantitatively analyzed the bias dependent photocurrent by a model of two back to back Schottky diodes connected by a series resistance. The observation shows that the large photoresponse of the device primarily occurs due to the reduction of the barrier at the contact regions due to illumination along with the photoconductive contribution. There is also a bias driven reduction of the nanowire resistance that is a unique feature for the material., Comment: 24 pages, 5 figures

We describe the preparation and optical characterisation of a coronene tetracarboxylate salt (CS) in polyvinyl alcohol (PVA) thin film solutions processed from water, neat or mixed with varying ratios of a europium tris(hexafluoroacetylacetoanto) diaquo complex [Eu(hfac)3(H2O)2]. Neat CS-PVA showed not only well-defined fluorescence peaks but also a long-lived phosphorescence emission, persisting for more than 1 second. Interaction between the CS and EuIII molecules, mediated by means of carboxylate coordination to the EuIII, was attained by simple incorporation into the PVA polymer matrix and resulted in energy transfer from the coronone antenna to the europium centre. Under various blend ratios of CS and the EuIII complex, total photoluminescence quantum yields of typically around 30 % were achieved. The straightforward processing of this type of self-assembled chromophore-lanthanide system into a luminescent polymer film offers potential for application to other chromophores, lanthanides and polymers.