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The development of n-type organic semiconductors has evolved significantly slower in comparison to that of p-type organic semiconductors mainly due to the lack of electron-deficient building blocks with stability and processability. However, to realize a variety of organic optoelectronic devices, high-performance n-type polymer semiconductors are essential. Herein, conjugated microporous polymers (CMPs) comprising isoindigo acceptor units linked to benzene or pyrene donor units (BI and PI) showing n-type semiconducting behavior are reported. In addition, considering the challenges of deposition of a continuous and homogeneous thin film of CMPs for accurate Hall measurements, a plasma-assisted fabrication technique is developed to yield uniform thin films. The fully conjugated 2D networks in PI- and BI-CMP films display high electron mobility of 6.6 and 3.5 cm2 V−1 s−1, respectively. The higher carrier concentration in PI results in high conductivity (5.3 mS cm−1). Both experimental and computational studies are adequately combined to investigate structure–property relations for this intriguing class of materials in the context of organic electronics.

Highly active nickel phosphide (Ni2P) nanoclusters confined in a mesoporous SiO2 catalyst were synthesized by a two-step process targeting tight control over the Ni2P size and phase. The Ni precursor was incorporated into the MCM-41 matrix by one-pot synthesis, followed by the phosphorization step, which was accomplished in oleylamine with trioctylphosphine at 300 °C so to achieve the phase transformation from Ni to Ni2P. For benchmarking, Ni confined by the mesoporous SiO2 (absence of phosphorization) and 11 nm Ni2P nanoparticles (absence of SiO2) was also prepared. From the microstructural analysis, it was found that the growth of Ni2P nanoclusters was restricted by the mesoporous channels, thus forming ultrafine and highly dispersed Ni2P nanoclusters (<2 nm). The above approach led to promising catalytic performance following the order u-Ni2P@m-SiO2 > n-Ni2P > u-Ni@m-SiO2 > c-Ni2P in the selective hydrogenation of SO2 to S. In particular, u-Ni2P@m-SiO2 exhibited SO2 conversions of 94% at 220 °C and ∼99% at 240 °C, which are higher than the 11 nm stand-alone Ni2P particles (43% at 220 °C and 94% at 320 °C), highlighting the importance of the role played by SiO2 in stabilizing ultrafine nanoparticles of Ni2P. The reaction activation energy Ea over u-Ni2P@m-SiO2 is ∼33 kJ/mol, which is lower than those over n-Ni2P (∼36 kJ/mol) and c-Ni2P (∼66 kJ/mol), suggesting that the reaction becomes energetically favored over the ultrafine Ni2P nanoclusters.

[Abstract] Two calix[4]arene systems, C234+ and C244+ – where 2 corresponds to the number of viologen units and 3–4 corresponds to the number of carbon atoms connecting the viologen units to the macrocyclic core – have been synthesized and led to the formation of [3]pseudorotaxanes when combined with either CB[7] or CB[8]. The [3]pseudorotaxanes spontaneously dissociate upon reduction of the bipyridinium units as the result of intramolecular dimerization of the two face-to-face viologen radical cations. CB[7] and CB[8]-based [2]pseudorotaxanes containing monomeric viologen guest model compounds, MC32+ and MC4+, do not undergo decomplexation and dimerization following electrochemical reduction of their bipyridinium units.

Bio-efficacy of Aureofungin-sol, an antifungal antibiotic, for control of downy mildew and powdery mildew of grape was evaluated during October 2008 - April 2009 fruiting season in vineyards at three locations in Maharashtra. Four to nine sprays of Aureofungin-sol, @ 0.108, 0.163 and 0.217 g/l, starting from 12-16 days to 46-75 days after fruit pruning gave good control of downy mildew on leaves and bunches, and increased harvestable yield over the Control. Similarly, four sprays of Aureofungin-sol @ 0.108 g/l at 11 to 20 days' interval at 65 days after pruning provided complete control of powdery mildew on leaves and bunches. No residue of Aureofungin-sol was found in harvest samples above the limit of detection (0.1 mg/kg).

Bio-efficacy of Aureofungin-sol, an antifungal antibiotic, for control of downy mildew and powdery mildew of grape was evaluated during October 2008 - April 2009 fruiting season in vineyards at three locations in Maharashtra. Four to nine sprays of Aureofungin-sol, @ 0.108, 0.163 and 0.217 g/l, starting from 12-16 days to 46-75 days after fruit pruning gave good control of downy mildew on leaves and bunches, and increased harvestable yield over the Control. Similarly, four sprays of Aureofungin-sol @ 0.108 g/l at 11 to 20 days' interval at 65 days after pruning provided complete control of powdery mildew on leaves and bunches. No residue of Aureofungin-sol was found in harvest samples above the limit of detection (0.1 mg/kg).

A computational model was developed to simulate the progressive damage of fiber-reinforced brittle matrix composites under uniaxial tensile loading. In conjunction with the basic material properties, this model used a size-distribution of the 'fiber-free zones' as an input for the development of small penny-shaped cracks at the early stage of loading. Stable extension of such non-steady-state cracks and the transition from non-steady-state to steady-state cracks were modeled using a stress-intensity formulation for a partially-bridged penny-shaped crack. Stress-strain relation was simulated by calculating the total engineering strain in the gage section as a function of the applied stress. Strain energies of the non-steady-state cracks and displacements of the fibers in the sliding zones of the steady-state cracks were calculated to estimate the total strain. Two unidirectional fiber-reinforced composites were investigated to test the predictive capability of this model. The stress-strain relation predicted by the model was in good agreement with that measured experimentally for a SiC-reinforced calcium aluminosilicate composite. A SiC-reinforced magnesium aluminosilicate composite showed less cumulative strain before fracture due to premature fiber failure. (MM)

Stress-state effects on the transformation yield stresses of commercial-grade ceria-partially-stabilized zirconia/alumina (Ce-TZP/Al2O3) composite and MgO-partially-stabilized zirconia (MG-PSZ) were studied in various biaxial tests and in hydraulic compression tests. The yield envelopes in tension-tension and tension-compression stress quadrants and the pressure sensitivity of the yield stress in uniaxial compression were rationalized by a hypothesis where stress-induced transformation is triggered by a critical value of the interaction energy calculated according to the method of Eshelby. Crack-tip transformation zone shapes and sizes and rising crack-growth-resistance behaviors were studied in Ce-TZP/Al2O3. The shape of the crack-tip transformation zones was not consistent with the derived yield criterion; however, the crack shielding developed by the elongated zones could be explained by zone shielding theories that took into account the observed zone shape and the variations in the monoclinic content within the zones. The variation of the R-curves with the sintering temperature was consistent with the effects of transformation zone shape and size on zone shielding. The Ce-TZP/Al2O3 composites were also shown to exhibit a genuine fatigue crack-growth phenomenon. Characteristics of their fatigue behavior included higher crack-growth rates in tension-tension cyclic loading as compared to crack-growth rates in peak sustained loads, lower threshold stress intensity for initiation of crack growth in fatigue and a systematic decrease of the thresholds with increasing transformation yield stress., PDF updated 12 Jul 2013.

A microcircuit grid technique was investigated and used to measure crack lengths in fatigue crack growth test specimens of an aluminum alloy (7075- T6) at room temperature and a nickel-based superalloy (Inconel 718) at 650 C as part of a Phase I SBIR program supported by the Air Force. Crack lengths were determined from stepwise changes in the resistance of microcircuit grids deposited on compact tension specimens by a photolithography process. Crack lengths assessed from discrete voltage changes recorded for a grid on a bridge circuit agreed closely with direct optical measurements. The fatigue crack growth data obtained from both alloys were in agreement with the data in the literature. Keywords: Microcircuit grids, Automated fatigue testing, High temperature test capability, Spectrum loading.