Stable ensemble brightness from nitrogen vacancy centers in nanodiamonds through optimized surface composition

Stable ensemble emission from nitrogen vacancy (NV) centers in nanodiamonds (NDs) is highly desirable for diverse areas ranging from bio-imaging to quantum optics. The uniqueness of NV centers lies in their opto-spin properties like energy level structure, emission range (620-850 nm) and optical spin polarization. The host matrix (NDs), however, put some limitation on the photo-physical properties of these color centers. One of the major issues is surface proximity (where high concentration of defects are present) of NV centers. The NV centers being highly sensitive to the neighboring environment are unstable in such circumstances. The surface of NDs mainly exhibit non-diamond carbon which is well-known quencher of emission due to NV centers. The surface composition for desirable photo-physical properties of NV centers is still unknown. Here, we have systemically studied the effect of oxidation time at low oxidation temperature (450 oC) on the selective removal of sp2 carbon, aqueous dispersion of NDs and emission collection due to NV centers at ensemble level. Among different air oxidations, heat treatment at 450 oC at residual time of 8 hours has been found to be suitable air oxidation conditions for the enhancement of brightness and ensemble photo-stability of NV centers

Stable ensemble brightness from nitrogen vacancy centers in nanodiamonds through optimized surface composition

1071-1079Stable ensemble emission from nitrogen vacancy (NV) centers in nanodiamonds (NDs) is highly desirable for diverse areas ranging from bio-imaging to quantum optics. The uniqueness of NV centers lies in their opto-spin properties like energy level structure, emission range (620-850 nm) and optical spin polarization. The host matrix (NDs), however, put some limitation on the photo-physical properties of these color centers. One of the major issues is surface proximity (where high concentration of defects are present) of NV centers. The NV centers being highly sensitive to the neighboring environment are unstable in such circumstances. The surface of NDs mainly exhibit non-diamond carbon which is well-known quencher of emission due to NV centers. The surface composition for desirable photo-physical properties of NV centers is still unknown. Here, we have systemically studied the effect of oxidation time at low oxidation temperature (450 oC) on the selective removal of sp2 carbon, aqueous dispersion of NDs and emission collection due to NV centers at ensemble level. Among different air oxidations, heat treatment at 450 oC at residual time of 8 hours has been found to be suitable air oxidation conditions for the enhancement of brightness and ensemble photo-stability of NV centers

Effect of fibre orientation on mechanical properties of carbon fibre composites

The research aims to investigate the carbon fibre composite laminate for effect of their layer configuration including their number and relative orientation of fibre angles on their mechanical properties and its consistency with the results obtained from simulated data using finite element analysis (FEA) on mechanical properties. The laminate composite with four types of fiber layer orientations were prepared using total eight layers including unidirectional and cross ply layers with different orientations. The flexural properties of the samples were evaluated. The results of experiments found consistent with the simulated data and it indicates that the fibre orientations and its layer sequence influence the characteristics of laminate composites. The composite with 0 orientated unidirectional fibre layers shows maximum flexural strength. The flexural strain is higher for laminate composite having layers with cross plies (45° fibre orientations). The different position of cross ply in the sequence shows variations in flexural properties because the typical nature of the three point bending flexural test of laminate composite where top side layers are under compression and bottom side layers are under tension

Synthesis of high surface area activated carbon from eucalyptus bark for the removal of methylene blue

In present study, high surface area (1852m2g−1) activated carbon was synthesized by single step thermo chemical activation of agro-waste lignocellulose biomass (eucalyptus bark).The synthesized activated carbon has been characterized using scanning electron microscopy, energy-dispersive-X-ray spectroscopy and BET surface area analyser. The eucalyptus bark derived activated carbon (EBAC) was used to remove methylene blue (MB) from waste water. The pH, contact time and concentration of dye were optimized and it was found that at pH of 5.5-6.5 at the room temperature, maximum removal of dye was observed. The obtained time data follows the pseudo second order kinetics. The effect of concentration study was carried out with varying concentration at optimized pH and time. The maximum adsorption capacity is obtained to be 7.15 mg/g. To understand the adsorption process, the Dubinin–Radushkevich (D–R) isotherm and Freundlich isotherm were used for fitting of equilibrium data. The fitted data follows D-R isotherm which reveals the physisorption process during adsorption of dye

Effect of fibre orientation on mechanical properties of carbon fibre composites

1100-1103The research aims to investigate the carbon fibre composite laminate for effect of their layer configuration including their number and relative orientation of fibre angles on their mechanical properties and its consistency with the results obtained from simulated data using finite element analysis (FEA) on mechanical properties. The laminate composite with four types of  fiber layer orientations were prepared using total eight layers including unidirectional and cross ply layers with different orientations. The flexural properties of the samples were evaluated. The results of experiments found consistent with the simulated data and it indicates that the fibre orientations and its layer sequence influence the characteristics of laminate composites. The composite with 0° orientated unidirectional fibre layers shows maximum flexural strength. The flexural strain is higher for laminate composite having layers with cross plies (45° fibre orientations). The different position of cross ply in the sequence shows variations in flexural properties because the typical nature of the three point bending flexural test of laminate composite where top side layers are under compression and bottom side layers are under tension

Stable ensemble brightness from nitrogen vacancy centers in nanodiamonds through optimized surface composition

1071-1079Stable ensemble emission from nitrogen vacancy (NV) centers in nanodiamonds (NDs) is highly desirable for diverse areas ranging from bio-imaging to quantum optics. The uniqueness of NV centers lies in their opto-spin properties like energy level structure, emission range (620-850 nm) and optical spin polarization. The host matrix (NDs), however, put some limitation on the photo-physical properties of these color centers. One of the major issues is surface proximity (where high concentration of defects are present) of NV centers. The NV centers being highly sensitive to the neighboring environment are unstable in such circumstances. The surface of NDs mainly exhibit non-diamond carbon which is well-known quencher of emission due to NV centers. The surface composition for desirable photo-physical properties of NV centers is still unknown. Here, we have systemically studied the effect of oxidation time at low oxidation temperature (450 oC) on the selective removal of sp2 carbon, aqueous dispersion of NDs and emission collection due to NV centers at ensemble level. Among different air oxidations, heat treatment at 450 oC at residual time of 8 hours has been found to be suitable air oxidation conditions for the enhancement of brightness and ensemble photo-stability of NV centers

Tracking the Nation: Material Sites of Trans-cultural Mobility in China Men

1059-1066In present study, high surface area (1852m2g−1) activated carbon was synthesized by single step thermo chemical activation of agro-waste lignocellulose biomass (eucalyptus bark).The synthesized activated carbon has been characterized using scanning electron microscopy, energy-dispersive-X-ray spectroscopy and BET surface area analyser. The eucalyptus bark derived activated carbon (EBAC) was used to remove methylene blue (MB) from waste water. The pH, contact time and concentration of dye were optimized and it was found that at pH of 5.5-6.5 at the room temperature, maximum removal of dye was observed. The obtained time data follows the pseudo second order kinetics. The effect of concentration study was carried out with varying concentration at optimized pH and time. The maximum adsorption capacity is obtained to be 7.15 mg/g. To understand the adsorption process, the Dubinin–Radushkevich (D–R) isotherm and Freundlich isotherm were used for fitting of equilibrium data. The fitted data follows D-R isotherm which reveals the physisorption process during adsorption of dye

Effect of fibre orientation on mechanical properties of carbon fibre composites

1100-1103The research aims to investigate the carbon fibre composite laminate for effect of their layer configuration including their number and relative orientation of fibre angles on their mechanical properties and its consistency with the results obtained from simulated data using finite element analysis (FEA) on mechanical properties. The laminate composite with four types of  fiber layer orientations were prepared using total eight layers including unidirectional and cross ply layers with different orientations. The flexural properties of the samples were evaluated. The results of experiments found consistent with the simulated data and it indicates that the fibre orientations and its layer sequence influence the characteristics of laminate composites. The composite with 0° orientated unidirectional fibre layers shows maximum flexural strength. The flexural strain is higher for laminate composite having layers with cross plies (45° fibre orientations). The different position of cross ply in the sequence shows variations in flexural properties because the typical nature of the three point bending flexural test of laminate composite where top side layers are under compression and bottom side layers are under tension