Enhanced photovoltaic performance using reduced graphene oxide assisted by triple-tail surfactant as an efficient and low-cost counter electrode for dye-sensitized solar cells

In this work, 4-bis(neopentyloxy)-3-(neopentyloxycarbonyl)-1,4-dioxobutane-2-silphonate (TC14) surfactant assisted reduced graphene oxide (rGO) was used as a counter electrode (CE) in dye-sensitized solar cell (DSSC). Field emission scanning electron microscopy and high-resolution transmission electron microscopy observations revealed that the TC14-rGO film was well dispersed on fluorine-doped tin oxide surface. The TC14-rGO modified CE based DSSC showed a power conversion efficiency of 0.828%, a short current density (JSC) of 2.72 mA cm−2, an open circuit voltage (VOC) of 0.65 V, and a fill factor (FF) of 41.9 which were higher than those CE fabricated from commercially available SDS surfactant assisted rGO. Results revealed that TC14-rGO is a potential CE material to construct efficient DSSC for future solar cell applications

Microwave Reflection Based Dielectric Spectroscopy for Moisture Content in Melele Mango Fruit (Mangifera Indica L.)

The Melele mango is one of the special local fruit Malaysia and it has high commercial value. However, the current methods are not efficient in determining optimum period to harvest. The optimum harvest time has close relationship with moisture content in fruit. The reflection based dielectric spectroscopic technique is conducted to measure moisture in Melele mango fruits. Dielectric and reflection measurements were conducted over a frequency range from 200 MHz to 8 GHz on clone Melele mango. Dielectric constant, loss factor and complex reflection coefficient of Melele mango with different moisture content were measured using an Agilent E8362B PNA Network Analyzer in conjunction with an Agilent 85070E High Temperature Probe over a frequency range from 200 MHz to 8 GHz. The measured reflection coefficient is presented in magnitude and phase. Dielectric constant and loss factor decreases when the moisture content in mango fruit decreases. The magnitude of the reflection coefficient descends due to increment of the dielectric constant. The results show that the measured dielectric properties and complex reflection coefficient provides the ability to predict fruit moisture content

Fabrication of Titanium Dioxide Nanorod Arrays-Polyaniline Heterojunction for Development of UV Photosensor

An ultraviolet (UV) photosensor is successfully fabricated via heterojunction device consisted of n-type titanium dioxide (TiO2) nanorod arrays (TNAs), and p-type polyaniline (PANI) by a facile method on fluorine tin oxide (FTO)-coated glass substrate. The fabricated UV photosensor demonstrated a UV-catalyst activity through the generation of photocurrent under UV irradiation (365 nm, 750 µW/cm2). The measured UV response showed the highest generation of photocurrent of 0.52 μAcm-2, and responsivity of 0.65 mA/W at 1.0 V reverse bias. The results indicate that the fabricated TNAs/PANI heterojunction-based device could be a promising candidate for the application of UV photosensor

Dye-sensitized solar cell using pure anatase TiO2 annealed at different temperatures

The performance of pure anatase titanium dioxide (TiO2) annealed at different tempera-tures as photoanode in the application of dye-sensitized solar cell (DSSC) was investigated and discussed. All samples of TiO2 were deposited on fluorine-doped tin oxide (SnO2) on glass substrate using spray pyrolysis deposition (SPD) method. Characterizations of the DSSCs fabricated were executed on their surface morphology, structural property, and energy conversion efficiency. In the DSSC preparation, anatase TiO2 thin films, platinum (Pt), ruthenium-based dye N719 and DPMII triiodide couple electrolyte were used as pho-toanodes, cathode/counter electrode, dye sensitizers and liquid electrolyte, respectively. All of the TiO2 photoanodes were annealed at 300 ◦C, 400 ◦C and 500 ◦C with a set left without any heat treatment. The thickness of anatase TiO2 photoanodes measured were in between 23 �m and 41 �m. The power conversion efficiency of DSSCs performed under visible light with intensity of 100 mW/cm2 shows that DSSC with pure anatase phased TiO2 annealed at 500 ◦C as photoanode yields the highest efficiency of 3.25%

Heterojunction of SnO2 nanosheet/arrayed ZnO nanorods for humidity sensing

For the first time, a rutile phased tin oxide (SnO2) nanosheet was assembled onto a zinc oxide (ZnO) nanorod array to form SnO2 nanosheet/ZnO nanorod array heterostructure films (TSZR) using a two-step solution immersion method. This study offers a facile and effective path to grow a SnO2 nanosheet assembled layer on ZnO nanorod arrays with a varied density using a tin (II) chloride dihydrate precursor to achieve an optimum humidity sensing response through the SnO2 growth time from 1 to 5 h. The structural characteristics, electrical properties, and humidity sensing response of the heterostructure films were investigated using various characterization techniques, such as field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, high-resolution transmission electron microscopy, X-ray diffraction, atomic force microscopy, Raman spectroscopy, a two-probe current-voltage measurement, and a humidity sensing response measurement system. The synthesized ZnO nanorods have an average diameter of 90 nm, while the grown SnO2 nanosheets have an average width of 20 nm. The humidity response performance of the films demonstrates a remarkable dependence on the SnO2 nanosheet assembled layer on the ZnO nanorod array film with the best humidity sensitivity of 754.4 at room temperature obtained for the 2 h-grown SnO2 nanosheet-based 2TSZR heterostructure sample. The 2TSZR sample also exhibited good stability over a four-cycle measurement and magnified current value of the humidity sensing response at a high operating temperature up to 60 °C. These investigations reveal that the TSZR heterostructure films are promising for humidity sensing devices with high sensitivity

Software engineering for self-adaptive systems:research challenges in the provision of assurances

The important concern for modern software systems is to become more cost-effective, while being versatile, flexible, resilient, dependable, energy-efficient, customisable, configurable and self-optimising when reacting to run-time changes that may occur within the system itself, its environment or requirements. One of the most promising approaches to achieving such properties is to equip software systems with self-managing capabilities using self-adaptation mechanisms. Despite recent advances in this area, one key aspect of self-adaptive systems that remains to be tackled in depth is the provision of assurances, i.e., the collection, analysis and synthesis of evidence that the system satisfies its stated functional and non-functional requirements during its operation in the presence of self-adaptation. The provision of assurances for self-adaptive systems is challenging since run-time changes introduce a high degree of uncertainty. This paper on research challenges complements previous roadmap papers on software engineering for self-adaptive systems covering a different set of topics, which are related to assurances, namely, perpetual assurances, composition and decomposition of assurances, and assurances obtained from control theory. This research challenges paper is one of the many results of the Dagstuhl Seminar 13511 on Software Engineering for Self-Adaptive Systems: Assurances which took place in December 2013

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02

Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio