Chelating and Bridging Roles of 2-(2-Pyridyl)benzimidazole and Bis(diphenylphosphino)acetylene in Stabilizing a Cyclic Tetranuclear Platinum(II) Complex.

The reaction of complex [Pt(Me)(DMSO)(pbz)], 1, (pbz = 2-(2-pyridyl)benzimidazolate) with [PtMe(Cl)(DMSO)2], B, followed by addition of bis(diphenylphosphino)acetylene (dppac), gave the novel tetranuclear platinum complex [Pt4Me4(μ-dppac)2(pbz)2Cl2], 2, bearing both the pbz and dppac ligands. In this structure, the pbz ligands are both chelating and bridging to stabilize the tetraplatinum framework. The tetranuclear Pt(II) complex was fully characterized by NMR spectroscopy, X-ray crystallography, and mass spectrometry, and its electronic structure was investigated and supported by DFT calculations

Time- and frequency-domain polariton interference

We present experimental observations of interference between an atomic spin coherence and an optical field in a {\Lambda}-type gradient echo memory. The interference is mediated by a strong classical field that couples a weak probe field to the atomic coherence through a resonant Raman transition. Interference can be observed between a prepared spin coherence and another propagating optical field, or between multiple {\Lambda} transitions driving a single spin coherence. In principle, the interference in each scheme can yield a near unity visibility.Comment: 11 pages, 5 figure

Decoding Charge Recombination through Charge Generation in Organic Solar Cells

The in‐depth understanding of charge carrier photogeneration and recombination mechanisms in organic solar cells is still an ongoing effort. In donor:acceptor (bulk) heterojunction organic solar cells, charge photogeneration and recombination are inter‐related via the kinetics of charge transfer states—being singlet or triplet states. Although high‐charge‐photogeneration quantum yields are achieved in many donor:acceptor systems, only very few systems show significantly reduced bimolecular recombination relative to the rate of free carrier encounters, in low‐mobility systems. This is a serious limitation for the industrialization of organic solar cells, in particular when aiming at thick active layers. Herein, a meta‐analysis of the device performance of numerous bulk heterojunction organic solar cells is presented for which field‐dependent photogeneration, charge carrier mobility, and fill factor are determined. Herein, a “spin‐related factor” that is dependent on the ratio of back electron transfer of the triplet charge transfer (CT) states to the decay rate of the singlet CT states is introduced. It is shown that this factor links the recombination reduction factor to charge‐generation efficiency. As a consequence, it is only in the systems with very efficient charge generation and very fast CT dissociation that free carrier recombination is strongly suppressed, regardless of the spin‐related factor

Construct-it: A board game to enhance built environment students’ understanding of the property life cycle

This article investigates the development of a board game entitled ‘Construct-it’ as an innovative pedagogical approach (as proof of concept) to augmenting the applied knowledge and understanding of built environment students studying property life cycle analysis. A largely qualitative and inductive methodological approach is conducted to identify and investigate the various pertinent theoretical frameworks that could be adopted; conduct a critical synthesis of extant literature; and develop Construct-it, a game intuitively grounded in practice-based knowledge. The study reveals that games provide a fun, engaging and challenging means of educating students at higher education institutions. It also notes a significant dearth of literature in terms of applying games to students enrolled on built environment programmes. Construct-it can enhance the student’s learning experience and knowledge of pertinent industry practice and standards and can complement traditional classroom teaching approaches. The study concludes with directions for the future work required to enhance the development of the novel pedagogical proof of concept presented. Such work will require robust testing and validation of the game to measure its impact on the student learning experience. </jats:p

Application of ZnO-Fe3O4 nanocomposite on the removal of azo dye from aqueous solutions: Kinetics and equilibrium studies

In this study, zinc oxide was immobilized on magnetite nanoparticles by chemical method and it was used as an adsorbent to remove reactive black 5 (RB5) dye from aqueous solution. The removal efficiency of RB5 was studied as the function of adsorbent dosage, pH, initial RB5 concentration, H2O 2, and ionic strength (sodium carbonate, sodium bicarbonate, sodium sulfate, and sodium chloride). Removal efficiency of RB5 by ZnO-Fe 3O4 was greater than that by ZnO and Fe3O 4 in similar conditions. Maximum adsorption of ZnO-Fe 3O4 was obtained at neutral pH, and adsorption capacity was estimated to be 22.1 mg/g. Adsorption kinetic study revealed that the pseudo-second-order model better described the removal rate than the pseudo-first-order model. Adsorption isotherm was analyzed by both Langmuir and Freundlich equations, and results showed that it was better described by the Langmuir equation. The removal efficiency of RB5 was increased with increasing initial H2O2 concentrations from 2 to 5 mM but was decreased above 5 mM. The adsorption capacities of RB5 was increased in the presence of NaCl but was greatly decreased in the presence of bicarbonate, carbonate, and sulfate ion. Adsorption activity of RB5 by ZnO-Fe 3O4 composite was maintained even after five successive cycles, suggesting a promising adsorbent for wastewater-contaminated organic dyes. © Springer International Publishing Switzerland 2014

BIM adoption within Australian small and medium-sized enterprises (SMEs) : an innovation diffusion model

Despite the envisaged benefits of BIM adoption for SMEs, BIM in SMEs has remained an underrepresented area within the available academic literature. This study proposes and draws upon a framework grounded on innovation diffusion theory (IDT) to provide an illuminating insight into the current state of BIM and the main barriers to BIM adoption within Australian SMEs. Based on analyses of 135 questionnaires completed by SMEs through partial least squares structural equation modelling (PLS-SEM) and grounded on the proposed framework, the current state of BIM adoption and barriers to BIM adoption for SMEs are discussed. The findings show that currently around 42% of Australian SMEs use BIM in Level 1 and Level 2 with only around 5% have tried Level 3. It comes to light that lack of knowledge within SMEs and across the construction supply chain is not a major barrier for Australian SMEs. In essence, the main barriers stem from the risks associated with an uncertain return on investment (ROI) for BIM as perceived by key players in SMEs. The findings also show the validity of the framework proposed for explaining BIM adoption in Australian SMEs