An Analog Circuit for Accurate OCVD Measurements
An electronic circuit for making accurate open-circuit voltage decay measurements is presented. The circuit overcomes the main limitations that occur in the standard method when used for carrier lifetime characterization because it realizes the ldquoopen-circuit conditionsrdquo of the device under test with an impedance higher than 100 MOmega and reduces the noise that is inherent in the differential operation of the method.
Evaluation of NB-PLC in railway environments
In this paper, the possibility to use Narrow-Band Power-Line Communication (NB-PLC), based on PRIME and G3-PLC protocols, in a particular harsh environment is demonstrated, with the purpose to significantly reduce the cable infrastructure and the related costs. To this end, the performances of a NB-PLC system have been measured when it is used in conjunction with an a.c. single phase power-line that delivers energy to the light signals in a railway environment. The context is very representative, since the lights in a terminal station and, hence, their controlling signals must obey to severe security standards and operate in a very harsh environment, populated by many electromagnetic interferences of several typologies, power sources and drain nodes. A testbed has been built, composed by the power generation core, the PLC modems and a cable long up to 2250m. Performance in terms of PSNR, RS SI, Throughput and BER have been reported for the entire modulation scheme that the PLC protocols enable.
Comparison between Two Chemicals for Reducing Scale Formation in Reverse Osmosis Systems
In this present research was transacted with the calcium carbonate scale inhibition on the membrane surface of the reverse osmosis desalination system. Influence of changing feed solution flow rate (10-25)l/h, pH of the feed solution (6-10) on the recovery ,penetrate flow rate and total dissolved solid in (RO) system by using solution of calcium carbonate as feed solution was investigated, furthermore the effect of adding two types of scale inhibitor ,zinc chloride and polyamino polyether methylene phosphonate with difference concentration (2-8)mg/l for zinc chloride and (8-15) mg/l for polyamino polyether methylene phosphonate was calculated. The results showed that the permeate rate increases as the feed flow rate augmentation ,while it reducing with time, the total dissolved solids decreases as the feed flow rate increases while it increases with time and recovery rate decreases as the feed flow rate increases and it also decreases with time. It was concluded that the permeate rate decreases as the feed solution pH value increases and it cause high scale forming thus decrease the permeate TDS.By adding the scale inhibitor, it was found that the permeate rate and recovery rates increases as the concentration of inhibitor increases while the total dissolved solids decreases in the permeate with increasing the concentration of both inhibitors .It was discovered that Polyamino polyether methylene phosphonate more sturdy than zinc chloride as scale inhibitor for reverse osmosis desalination system in all concentrations was studied in this article.