The combined effect of superficial nanocrystallisation by SMAT (Surface Mechanical Attrition Treatment) followed by plasma nitriding on the mechanical properties of a medical grade austenitic stainless steel was studied. SMAT conditions were optimised to enhance nitrogen diffusion. Experimental observations (energy dispersive X-ray spectroscopy profiles, cross-sectional optical micrographs, pha...

The effect which nitrogen has upon boron diffusion through oxynitride gate dielectrics has been studied with secondary ion mass spectroscopy of polycrystalline silicon–oxynitride–silicon structures, and with x-ray photoelectron spectroscopy of silicon–boron–oxynitride–silicon structures. These studies show that the indiffusion of boron results in removal of nitrogen from the oxynitride. This in...

The activation energy of nitrogen diffusion in R2Fe,, (R=rare earth) compounds has been determined by applying the Kissinger method to analyse the differential scanning calorimetry (DSC) traces of nitrogenated R2Fe1, compounds. The nitrogen outgas that starts when the nitrides are heated above about 300 “C is a typical decomposition reaction of the type solid + solid + gas to which the Kissinge...

Thanks to the new satellite technology, global scenes of the dynamical and chemical processes of the atmospheric compounds can be drawn. Ground-based equipments have to be used for comparison/validation of the satellite retrievals. The SPATRAM (SPectrometer for Atmospheric TRacers and Aerosol Measurement) is a UV-Vis spectrometer allowing for the measurements of spectral sky radiance along the ...

In the absence of sufficient combined nitrogen, some filamentous cyanobacteria differentiate nitrogen-fixing heterocysts at approximately every 10th cell position. As cells between heterocysts grow and divide, this initial pattern is maintained by the differentiation of a single cell approximately midway between existing heterocysts. This paper introduces a mathematical model for the maintenanc...

In this work, adsorption kinetics were investigated in order to remove the acid blue 62 off the aqueous solutions using mesoporous silicate SBA-15 loaded with tannic acid (tannin-SBA-15). Nitrogen adsorption and desorption test (BET), X-ray diffraction (XRD) and Fourier transform infra-red spectroscopy (FT-IR) analysis characterize synthesized composite. The impacts of some parameters such as P...

Eutrophication remains one of the foremost impacts of industrialization and population expansion on aquatic ecosystems worldwide. Selecting metrics for assessing the manner in which communities and biogeochemical processes respond to nutrient fertilization is an ongoing management challenge critical both for detecting changes and for monitoring recovery of impaired environments. A key limitatio...

The solid state reaction of CUWO4-2 formation from CuO and WO3 was studied by the contact method in air and nitrogen. The results showed that the reaction is governed by the diffusion of the W 6 + and 0 2 _ ions and that the rate determining step is the diffusion of oxygen ions in the reaction product. This is in agreement with the defect structure of copper tungstate, an n-type semiconductor w...

We present results of ab initio calculations for vacancies and divacancies in GaN. Particular attention is paid to nitrogen vacancies and mixed Ga-N divacancies in negatively charged states, which in n-type GaN are found to be energetically comparable with gallium vacancies. We also demonstrate that the activation energy for self-diffusion over the nitrogen sublattice is lower than over the gal...

A NaCl-modified zeolite was used to simultaneously remove nitrogen and phosphate from biogas slurry. The effect of pH, contact time and dosage of absorbants on the removal efficiency of nitrogen and phosphate were studied. The results showed that the highest removal efficiency of NH4+-N (92.13%) and PO43--P (90.3%) were achieved at pH 8. While the zeolite doses ranged from 0.5 to 5 g/100 ml, NH...