InGaAsP-InP ridge-waveguide DBR lasers with first-order surface gratings fabricated using CAIBE

1997 ◽  
Vol 9 (11) ◽  
pp. 1445-1447 ◽  
Author(s):  
R.M. Lammert ◽  
A.M. Jones ◽  
C.T. Youtsey ◽  
J.S. Hughes ◽  
S.D. Roh ◽  
...  
Keyword(s):  
Ridge Waveguide ◽  
First Order ◽  
Dbr Lasers ◽  
Order Surface

Low-threshold narrow-linewidth InGaAs-GaAs ridge-waveguide DBR lasers with first-order surface gratings

1997 ◽  
Vol 9 (2) ◽  
pp. 149-151 ◽  
Author(s):  
R.M. Lammert ◽  
J.S. Hughes ◽  
S.D. Roh ◽  
M.L. Osowski ◽  
A.M. Jones ◽  
...  
Keyword(s):  
Ridge Waveguide ◽  
Narrow Linewidth ◽  
First Order ◽  
Low Threshold ◽  
Dbr Lasers ◽  
Order Surface

Biodegradation rates of aromatic contaminants in biofilm reactors

1995 ◽  
Vol 31 (1) ◽  
pp. 117-128 ◽  
Author(s):  
Jean-Pierre Arcangeli ◽  
Erik Arvin
Keyword(s):  
Aromatic Hydrocarbons ◽  
Competitive Inhibition ◽  
Removal Rate ◽  
First Order ◽  
Biofilm Reactors ◽  
First Order Kinetics ◽  
Reducing Conditions ◽  
Low Concentrations ◽  
Degradation Rates ◽  
Order Surface

This study has shown that microorganisms can adapt to degrade mixtures of aromatic pollutants at relatively high rates in the μg/l concentration range. The biodegradation rates of the following compounds were investigated in biofilm systems: aromatic hydrocarbons, phenol, methylphenols, chlorophenols, nitrophenol, chlorobenzenes and aromatic nitrogen-, sulphur- or oxygen-containing heterocyclic compounds (NSO-compounds). Furthermore, a comparison with degradation rates observed for easily degradable organics is also presented. At concentrations below 20-100 μg/l the degradation of the aromatic compounds was typically controlled by first order kinetics. The first-order surface removal rate constants were surprisingly similar, ranging from 2 to 4 m/d. It appears that NSO-compounds inhibit the degradation of aromatic hydrocarbons, even at very low concentrations of NSO-compounds. Under nitrate-reducing conditions, toluene was easily biodegraded. The xylenes and ethylbenzene were degraded cometabolically if toluene was used as a primary carbon source; their removal was influenced by competitive inhibition with toluene. These interaction phenomena are discussed in this paper and a kinetic model taking into account cometabolism and competitive inhibition is proposed.

Heat/mass transport in shear flow over a heterogeneous surface with first-order surface-reactive domains

2015 ◽  
Vol 782 ◽  
pp. 260-299 ◽  
Author(s):  
Preyas N. Shah ◽  
Eric S. G. Shaqfeh
Keyword(s):  
Mass Transfer ◽  
Shear Rate ◽  
Shear Flow ◽  
Reaction Rate ◽  
Patch Size ◽  
Patch Area ◽  
First Order ◽  
Effective Boundary ◽  
Order Surface ◽  
Slip Distance

Surfaces that include heterogeneous mass transfer at the microscale are ubiquitous in nature and engineering. Many such media are modelled via an effective surface reaction rate or mass transfer coefficient employing the conventional ansatz of kinetically limited transport at the microscale. However, this assumption is not always valid, particularly when there is strong flow. We are interested in modelling reactive and/or porous surfaces that occur in systems where the effective Damköhler number at the microscale can be $O(1)$ and the local Péclet number may be large. In order to expand the range of the effective mass transfer surface coefficient, we study transport from a uniform bath of species in an unbounded shear flow over a flat surface. This surface has a heterogeneous distribution of first-order surface-reactive circular patches (or pores). To understand the physics at the length scale of the patch size, we first analyse the flux to a single reactive patch. We use both analytic and boundary element simulations for this purpose. The shear flow induces a 3-D concentration wake structure downstream of the patch. When two patches are aligned in the shear direction, the wakes interact to reduce the per patch flux compared with the single-patch case. Having determined the length scale of the interaction between two patches, we study the transport to a periodic and disordered distribution of patches again using analytic and boundary integral techniques. We obtain, up to non-dilute patch area fraction, an effective boundary condition for the transport to the patches that depends on the local mass transfer coefficient (or reaction rate) and shear rate. We demonstrate that this boundary condition replaces the details of the heterogeneous surfaces at a wall-normal effective slip distance also determined for non-dilute patch area fractions. The slip distance again depends on the shear rate, and weakly on the reaction rate, and scales with the patch size. These effective boundary conditions can be used directly in large-scale physics simulations as long as the local shear rate, reaction rate and patch area fraction are known.

scholarly journals Imaging of first-order surface-related multiples by reverse-time migration

2016 ◽  
Vol 208 (2) ◽  
pp. 1077-1087 ◽  
Author(s):  
Xuejian Liu ◽  
Yike Liu ◽  
Hao Hu ◽  
Peng Li ◽  
Majid Khan
Keyword(s):  
Reverse Time ◽  
Reverse Time Migration ◽  
First Order ◽  
Time Migration ◽  
Order Surface

First order surface roughness correction of active microwave observations for estimating soil moisture

1997 ◽  
Vol 35 (4) ◽  
pp. 1065-1069 ◽  
Author(s):  
T.J. Jackson ◽  
H. McNairn ◽  
M.A. Weltz ◽  
B. Brisco ◽  
R. Brown
Keyword(s):  
Surface Roughness ◽  
Soil Moisture ◽  
First Order ◽  
Order Surface
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