Finite element study on the influence of pore size and structure on stress shielding effect of additive manufactured spinal cage.

The stress shielding effect occurs when the orthopedic implant reduces the load delivered to the bone, causing inefficient stress transfer to the host bone. The usage of porous additive manufactured (AM) cages reduces the stress shielding effect and promotes bone ingrowth also. The purpose of this work is to study the stress and deformation on porous hybrid spinal cages under different loading conditions using Finite Element Analysis (FEA).

Soil concentrations and soil-air exchange of polycyclic aromatic hydrocarbons in five Asian countries.

The Asia Soil and Air Monitoring Program (Asia-SAMP) is a large-scale monitoring program spanning China, Japan, South Korea, Vietnam and India. 47 polycyclic aromatic hydrocarbons (PAHs) were analyzed in 169 concurrently collected surface soil samples across the five study regions. Total PAH concentrations (∑PAHs) ranged from 13.

Occurrence and Source Effect of Novel Brominated Flame Retardants (NBFRs) in Soils from Five Asian Countries and Their Relationship with PBDEs.

This paper presents the first comprehensive survey of 19 novel brominated flame retardants (NBFRs) in soil samples collected among five Asian countries. High variability in concentrations of all NBFRs was found in soils with the geometric mean (GM) values ranging from 0.50 ng/g dry weight (dw) in Vietnam to 540 ng/g dw in the vicinity of a BFR manufacturer in China.

Experimental and theoretical study of hydroxyquinolines: hydroxyl group position dependent dipole moment and charge-separation in the photoexcited state leading to fluorescence.

Optical absorption and fluorescence (FL) spectra of 2-, 6-, 7-, 8-hydroxyquinolines (2-,6-,7- and 8-HQs) have been measured at room temperature in the wide range of solvents of different polarities, dielectric constant and refractive index. The ground state dipole moment (µ ) and excited state dipole moment (µ ) of 2-, 6-, 7- and 8-HQs were obtained using solvatochromic shift (SS) methods and microscopic solvent polarity parameters (MSPP). Change in the dipole moment (Δµ) between the ground and photo-excited states was estimated from SS and MSPP methods.

Ultra broadband mid-IR supercontinuum generation in GeAsSe based chalcogenide graded-index photonic crystal fiber: design and analysis.

In this paper, we report design and numerical analysis of a GeAsSe based chalcogenide glass graded-index photonic crystal fiber structure for mid-IR ultra broadband supercontinuum generation. The proposed dispersion engineered photonic crystal fiber offers a zero dispersion wavelength at a pump wavelength of 2.8 μm.

Design and analysis of single-mode tellurite photonic crystal fibers for stimulated Brillouin scattering based slow-light generation.

We theoretically examine two designs of single-mode (i) Er-doped tellurite and (ii) undoped tellurite photonic crystal fiber (PCF) for generation of slow light with tunable features based on stimulated Brillouin scattering. We obtained (i) Brillouin gain up to 91 dB and time delay of ∼145  ns at maximum allowable pump power of ∼775  mW in a 2 m Er-doped tellurite PCF and (ii) Brillouin gain up to ∼88  dB and time delay of ∼154  ns at maximum allowable pump power ∼21  mW in a 100 m undoped tellurite photonic crystal fiber. Simulated results clearly indicate that the doped tellurite PCF with Er enhances the maximum allowable pump power and comparable time delay can be obtained even with reduced photonic crystal fiber length.

Design and analysis of a highly nonlinear composite photonic crystal fiber for supercontinuum generation: visible to mid-infrared.

A composite photonic crystal fiber structure has been designed with tellurite as the cladding and chalcogenide as a core material. To increase nonlinearity, rods of the chalcogenide glass material have been inserted around the core region. The reported structure offers very high nonlinearity of 1042  W Km at 2800 nm pump wavelength with low and flattened dispersion of approximately -11  ps·nm Km.

Large-mode-area single-polarization single-mode photonic crystal fiber: design and analysis.

A rectangular core photonic crystal fiber structure has been presented and analyzed for single-polarization single-mode operation. Single-polarization is obtained with asymmetric design and by introducing different loss for x-polarization and y-polarization of fundamental modes. Single-polarization single-mode operation of the proposed photonic crystal fiber is investigated in detail by using a full vector finite element method with an anisotropic perfectly matched layer.

Asymmetric large-mode-area photonic crystal fiber structure with effective single-mode operation: design and analysis.

The asymmetrical structure of photonic crystal fiber has been reported for a large mode area with the single-mode operation. The design works on the principle of bend-induced mode filtering. The proposed structure can be designed (i) by introducing down-doped material rods in place of nine air holes of the inner ring near the core of the structure and (ii) by increasing the diameter of the rest of the three air holes of the same ring in the direction of bending.

Design and analysis of large-core multitrench channel waveguide for high-power applications.

We present a multitrench leaky channel waveguide design that supports effective single-mode operation even with large-core size. The proposed waveguide structure has a uniform rectangular core and a geometrically shaped trench-assisted cladding in such a way that all the confined modes become leaky. The effective single-mode operation is achieved by choosing the appropriate geometrical parameters that introduce very large leakage losses for higher-order modes with very low leakage losses for fundamental mode.

Triangular-core large-mode-area photonic crystal fiber with low bending loss for high power applications.

A triangular-core large-mode-area photonic crystal fiber structure has been designed with lower bending loss. The design works on the principle of bend induced mode filtering. Effects of the design parameters have been numerically investigated using the full vectorial finite-element method.

Field emission with ultralow turn on voltage from metal decorated carbon nanotubes.

A simple and scalable method of decorating 3D-carbon nanotube (CNT) forest with metal particles has been developed. The results observed in aluminum (Al) decorated CNTs and copper (Cu) decorated CNTs on silicon (Si) and Inconel are compared with undecorated samples. A significant improvement in the field emission characteristics of the cold cathode was observed with ultralow turn on voltage (Eto ∼ 0.

Assessment of temporal variation in water quality of some important rivers in middle Gangetic plains, India.

The study explains water quality of three important tributaries of the Ganga River in the middle Gangetic plains in India. Seasonal changes in the water quality of the studied rivers: Gandak, Ghaghra, and Sone were observed. During monsoon, several water quality parameters show considerable changes due to increased runoff from the catchments and other seasonal factors.

Phylogenetic position of Platanista gangetica: insights from the mitochondrial cytochrome b and nuclear interphotoreceptor retinoid-binding protein gene sequences.

The evolutionary relationship of peculiar and poorly known Ganges River dolphin with extinct and extant cetaceans has been in the state of confusion for more than a century. The close resemblance of platanistidae with some of the extinct taxon viz., Dalpiaziniidae and Waipatiidae and their sister group relationship with many of the extant lineages of cetaceans has been reported but none of the alternative hypotheses provide an unambiguous placement for this species.