v. dannon showed that spherical curves in e4 can be given by frenet-like equations, and he thengave an integral characterization for spherical curves in e4 . in this paper, lorentzian spherical timelike andspacelike curves in the space time 41 r are shown to be given by frenet-like equations of timelike andspacelike curves in the euclidean space e3 and the minkowski 3-space 31 r . thus, finding...

in this study, bimodal meso-porous silica (uvm-7) synthesized and fabricated amino silane modified supports were characterized by powder x-ray diffraction (xrd), n2 adsorption/desorption, transmission electron microscope (tem), elemental analysis and titration. capacity of co2 capture on modified bimodal pore structure silica at 70°c was calculated using breakthrough curves; and it was found th...

Polycyclic aromatic hydrocarbons (PAHs), abundant in mixed contaminant sites, often coexist with heavy metals. The fate and remediation of PAHs depend heavily on the sorption and desorption behavior of these contaminants. The sorption behavior can in turn be highly affected by certain soil components and properties, such as soil organic matter (SOM) and the presence of heavy metals. Through rev...

Despite considerable attention in the literature being given to the desorption behaviour of smaller volatiles, the thermal properties of complex organics, such as ethanol (C(2)H(5)OH), which are predicted to be formed within interstellar ices, have yet to be characterized. With this in mind, reflection absorption infrared spectroscopy (RAIRS) and temperature programmed desorption (TPD) have bee...

a method was developed for removal, preconcentration and spectrophotometric determination of trace amounts of methyl red based on sio2-coated fe3o4magnetic nanoparticles. the influence of ph, dosage of adsorbent and contact time on the adsorption of dye was explored by central composite design. the kinetic data were analyzed based on the langmuir and freundlich adsorption isotherms. the langmui...

organic acids exuded by plant roots increase solubility of soil micronutrient complexes. this study was carried out to evaluate adsorption isotherms of 4 acidic and 4 calcareous soils at presence of organic acids (citric, malic and oxalic acids). iron sorption and desorption isotherms are defined in to two systems including; system 1; soil-water-metal, system 2; soil-water-organic acid-metal). ...

this paper discusses the biosorption of ni(ii) ions from aqueous solutions by bacillus sphaericus biomass. the biosorption process was affected by the solution ph, biomass concentration, contact time, temperature and initial ni(ii) concentration respectively. the sorption kinetics and equilibrium data were described well with the pseudo-second order kinetic model and the freundlich isotherm mod...

We report that ammonia borane with a high uptake capacity for hydrogen can be encapsulated in a metal-organic framework (MOF) via capillary action, where the MOF functions as a chemical guide to control the hydrogen desorption pathways of ammonia borane by releasing only pure hydrogen, lowering its hydrogen desorption temperature, and suppressing its volumetric expansion during hydrogen desorpt...