Extremely low back facet feedback by quantum-confined Stark effectabsorption in an edge-emitting light-emitting diode

The quantum-confined Stark effect is employed to form an integral reverse-biased absorber in a GaInAsP edge-emitting light-emitting diode. Optical low coherence reflectometry is used to measure the magnitude of reflections through this absorber. Front-facet-back-facet roundtrip reflection magnitudes are below -110 dB in devices having an antireflection coating on the front facet only. All other round trip reflections are below -80 dB. This device provides a wide usable dynamic range in optical low coherence reflectometry measurements     

Evanescent amplification in a single-mode optical fibre

By replacing a portion of the cladding of a single-mode fibre with a laser dye, amplification can be achieved by means of an evanescent field interaction. External gains as high as 22 dB have been measured by guiding both a pulsed pump and CW signal within the single-mode fibre.     

Isovaleric acidemia. Study and treatment in 3 brothers

The cases of 3 sibs presenting with isovaleric acidemia are reported. The first infant died when he was 9 day-old. The two others appear to have benefited from a controlled leucine diet which was introduced from the first days on of life. The clinical symptomatology, highly typical of the disease, is described. Diagnosis was not assessed on amino-acids chromatography but on the chromatography of volatile fatty acids. The mode of treatment is described: peritoneal dialysis, with the object of rounding a crucial cape, and overall controlled leucine diet, but supplemented by essential amino-acids.     

Treatment of methyl tert-butyl ether contaminated water using a dense medium plasma reactor: a mechanistic and kinetic investigation

Plasma treatment of contaminated water appears to be a promising alternative for the oxidation of aqueous organic pollutants. This study examines the kinetic and oxidation mechanisms of methyl tert-butyl ether (MTBE) in a dense medium plasma (DMP) reactor utilizing gas chromatography-mass spectrometry and gas chromatography-thermal conductivity techniques. A rate law is developed for the removal of MTBE from an aqueous solution in the DMP reactor. Rate constants are also derived for three reactor configurations and two pin array spin rates. The oxidation products from the treatment of MTBE-contaminated water in the DMP reactor were found to be predominately carbon dioxide, with smaller amounts of acetone, tert-butyl formate, and formaldehyde. The lack of stable intermediate products suggests that the MTBE is, to some extent, oxidized directly to carbon dioxide, making the DMP reactor a promising tool in the future remediation of water. Chemical and physical mechanisms together with carbon balances are used to describe the formation of the oxidation products and the important aspects of the plasma discharge.     

On maximum power of reverse osmosis separation processes

This paper considers the application of finite time thermodynamics (FTT) to reverse osmosis (RO) processes. A new thermodynamically ideal model of the endoreversible RO process is proposed and combined with basic transport equations for the irreversible mass transfer through the membrane. This approach is then applied to a simplified case of RO desalting of a concentrated sodium chloride solution. The results emphasize the trade-off between the permeate flow rate and the recovery rate. It also shows the existence of a maximum value for the power of separation which corresponds to the maximum conversion rate of mechanical exergy into chemical exergy. Finally the environmental and technical significances of the criteria such as power of separation are discussed on an example of the RO process.