Numerical modelling of continuous concrete box girder bridges considering construction stages

The aim of this study is to analyse the concrete continuous box girder bridges by considering segmentally construction stages through balanced cantilever method. Time-dependent material properties of concrete and steel are also taken into account. Budan Bridge is selected as a numerical example. The Bridge constructed with balanced cantilever method and located on Artvin–Erzurum highway, Turkey, at 55 + 729.00–56 + 079.00 km is modelled using SAP2000 program. Geometric nonlinearities are taken into consideration in the analysis using P-Delta and large displacement criterion. Time-dependent material properties are considered as compressive strength, aging, shrinkage and creep for concrete, and relaxation for steel. The structural behaviour of the bridge at different construction stages is examined. Variation of internal forces such as bending moment, shear forces and axial forces, and displacements for bridge deck and pier are given with detail.Analyses show that, to obtain real behaviour of concrete bridges, segmentally construction stage analysis using time dependent material properties and geometric nonlinearity should be considered, because construction period continue along time and loads may change during this period and after.     

Integrated Devices for Non-Invasive Diagnostics

“Sample-in-answer-out” type integrated diagnostic devices have been widely recognized as the ultimate solution to simplify testing across healthcare systems. Such systems are equipped with advanced fluidic, mechanical, chemical, biological, and electronic components to handle patient samples without any manual steps therefore have the potential to accelerate intervention and improve patient outcomes. In this regard, the combination of integrated devices and non-invasive sampling has gained a substantial interest to further improve the comfort and safety of patients. In this Review, the pioneering developments in integrated diagnostics are covered and their potential in non-invasive sampling is discussed. The key properties of possible sample types are highlighted by addressing their relevance for the clinical practice. Last, the factors affecting the transition of integrated devices from academia to the market are identified by analyzing the technology readiness levels of selected examples and alternative remedies are explored to increase the rate of survival during this transition.     

Inclusion complexation of warfarin withβ-cyclodextrins and its influence on absorption kinetics of warfarin in rat

The inclusion complexes of warfarin withβ-cyclodextrin, 2-hydroxypropyl-β-CD and methyl-β-CD have been investigated in aqueous solution. The apparent binding constants of warfarin are found to be 542±19, 442±18 and 112±6M^?1 respectively, calculated from the increments in fluorescence emission of the drug. The influence of theβ-CDs on the absorption rate of the drug is investigated within situ experiments in a chronically isolated internal loop, in the small intestine of the rat. The first-order disappearance (absorption) rate constant decreases to 3.6×10^?4 min^?1 inβ-CD, to 5.0×10^?4 min^?1 in 2-hydroxypropyl-β-CD and to 1.4×10^?3 min^?1 in methyl-β-CD compared to 3.2×10^?3 min^?1 in isotonic phosphate buffer (pH=7.4) solution, all of them showing a good agreement with the percentage of free warfarin in their complexed solutions: 16%, 18% and 47% calculated, respectively.     

Carbon fiber microelectrodes electrocoated with polycarbazole and poly(carbazole-co-p-tolylsulfonyl pyrrole) films for the detection of dopamine in presence of ascorbic acid

Polycarbazole (PCz) and poly(carbazole-co-p-tolylsulfonyl pyrrole) (PCz-co-p-Tsp) films were electrochemically deposited on single carbon fiber microelectrodes using LiClO₄ as electrolyte and acetonitrile as a solvent. The response of the sensors was tested towards different dopamine concentrations. The effect of ascorbic acid on the dopamine signal was analyzed by differential pulse voltammetry. Sensors displaying amperometric response to dopamine concentrations with a detection limit of 0.27 μM dopamine (3S/N) for the PCz modified CFE and 0.5 μM dopamine (3S/N) for the PCz-co-p-Tsp modified CFE; and an efficient protection against ascorbic acid interference at physiology concentration values (500 μM) were obtained. Correspondence: Wolfgang Schuhmann, Analytische Chemie, Elektroanalytik & Sensorik, Ruhr-Universit?t Bochum, D-44780 Bochum, Germany     

Determination of glutathione disulfide levels in biological samples using thiol-disulfide exchanging agent, dithiothreitol

A reverse-phase HPLC method incorporating dithiothreitol (DTT) reduction for quantitative determination of oxidized glutathione (GSSG) in biological samples is described here. This method is based on our previous enzymatic reduction technique that uses N-1-(pyrenyl) maleimide (NPM) as a derivatizing agent. In our earlier method, glutathione disulfide (GSSG) was measured by first reducing it to GSH with glutathione reductase (GR) in the presence of NADPH. However, this is a very costly and time-consuming technique. The method described here employs a common and inexpensive thiol-disulfide exchanging agent, DTT, for reduction of GSSG to GSH, followed by derivatization with NPM. The calibration curves are linear over a concentration range of 25-1250 nm (r(2) > 0.995). The coefficients of variations for intra-run precision and inter-run precision range from 0.49 to 5.10% with an accuracy range of 1.78-6.15%. The percentage of relative recovery ranges from 97.3 to 103.2%. This new method provides a simple, efficient, and cost-effective way of determining glutathione disulfide levels with a 2.5 nm limit of detection per 5 microL injection volume.     

Spherical Coding Algorithm for Wavelet Image Compression

In recent literature, there exist many high-performance wavelet coders that use different spatially adaptive coding techniques in order to exploit the spatial energy compaction property of the wavelet transform. Two crucial issues in adaptive methods are the level of flexibility and the coding efficiency achieved while modeling different image regions and allocating bitrate within the wavelet subbands. In this paper, we introduce the ldquospherical coder,rdquo which provides a new adaptive framework for handling these issues in a simple and effective manner. The coder uses local energy as a direct measure to differentiate between parts of the wavelet subband and to decide how to allocate the available bitrate. As local energy becomes available at finer resolutions, i.e., in smaller size windows, the coder automatically updates its decisions about how to spend the bitrate. We use a hierarchical set of variables to specify and code the local energy up to the highest resolution, i.e., the energy of individual wavelet coefficients. The overall scheme is nonredundant, meaning that the subband information is conveyed using this equivalent set of variables without the need for any side parameters. Despite its simplicity, the algorithm produces PSNR results that are competitive with the state-of-art coders in literature.     

Synthesis of ternary polypyrrole/Ag nanoparticle/graphene nanocomposites for symmetric supercapacitor devices

In this study, novel ternary synthesis of reduced graphene oxide (rGO) sheets via intercalation of Ag nanoparticles (Ag) and polypyrrole (PPy) was obtained for supercapacitor evaluations. The synthesis procedure of nanocomposite is simple, cheap, and ecologically friendly. The nanocomposites were analyzed by Fourier transform infrared-attenuated transmission reflectance (FTIR-ATR) and scanning electron microscopy-energy dispersion X-ray analysis (SEM-EDX). In addition, electrochemical performances of electrode active materials (rGO/Ag/PPy) of the samples were tested by means of galvanostatic charge/discharge (GCD), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The highest specific capacitance and energy density of rGO/Ag/PPy nanocomposite were obtained as C_sp = 1085.22 F/g and E = 36.92 Wh/kg for [rGO]_o/[Py]_o = 1/5 at 4 mV/s in 1 M H₂SO₄ solution. Under the optimized preparation conditions in different initial feed ratios ([rGO]_o/[Py]_o = 1/1, ½, 1/5, and 1/10) of rGO/Ag/PPy, nanocomposites acquired a high Coulombic efficiency, and a retention of 66% of its initial capacitance for [rGO]_o/[Py]_o = 1/10 after 1000 cycles. GCD and EIS measurements of rGO/Ag/PPy nanocomposite electrode active material allowed for supercapacitor applications.     

A generic framework for optimizing performance metrics by tuning parameters of clustering protocols in WSNs

Wireless Networks - Wireless sensor network (WSN) is a key technology trend in emerging internet of things paradigms which are commonly used for application areas such as smart-cities, smart-grids,...     

Carbazole derivative synthesis and their electropolymerization

This review article investigates the hot topics by presenting the latest advances in carbazole and its derivative synthesis and their electropolymerization processes. The carbazole-based compounds are particularly attractive due to their important photochemical and thermal stability and good hole-transport ability. Conjugated monomers of carbazole derivatives and their polymers attract interest due to their suitability in a broad range of applications, such as biosensors, corrosion inhibition, photovoltaics, electroluminescent devices, field-effect transistors and supercapacitors, etc. This review article divides two main parts. One of them includes effects of electropolymerization parameters of carbazole and chemical polymerization of carbazole derivatives. In addition, copolymers and composites of carbazole derivatives were presented in the first part. In the second part, the application of polycarbazole and its derivatives was examined as biosensors, corrosion inhibition, supercapacitor, battery, fuel cell, solar cell, electropolymerization, light emitting diodes, and OLEDs.