Natural source-based graphene as sensitising agents for air quality monitoring

Natural carbon powder has been used as a precursor to prepare two main types of sensitising agents of nitrogen-doped carbon nanoparticles (N-CNPs) and nitrogen-doped graphene quantum dots coupled to nanosheets (N-GQDs-NSs) by using simple treatments of chemical oxidation and centrifugation separation. Characterization based on FTIR, XPS, XRD, Raman spectroscopy, FE-SEM, HR-TEM, AFM, UV-Vis and FL, revealed successful doping carbon nanoparticle with nitrogen with an average plane dimension of 50 nm and relatively smooth surface. The versatility of the prepared samples as sensitising agents was developed and established by exploiting its ability for detection of volatile organic compounds via simple optical fibre based sensing configuration. The comparative experimental studies on the proposed sensor performance indicate fast response achieved at a few tens of seconds and excellent repeatability in exposure to the methanol vapour. The low limit of detection of 4.3, 4.9 and 10.5 ppm was obtained in exposure to the methanol, ethanol and propanol vapours, respectively, in the atmosphere condition. This study gives insights into the chemical/physical mechanism of an enhanced economic optical fibre based gas sensor and illustrates it for diverse sensing applications, especially for chemical vapour remote detection and future air quality monitoring

Investigation on effects of ergosan^TM and vibromax^TM in control of white spot disease (WSD) and Vibriosis in shrimp Litopenaeus vannamei

Complementary feedstuff extract from Laminaria digitata and Ascophylum nodosum that containing 1% alginic acids as shrimps stimulating of immune system for control of WSSV is used in this study. The test shrimps Litopenaeus vannamei in larvae stage (Z1-PL1), post larvae stage (PL1-PL10) and juvenile (from 30th day to 40th day) fed by complimentary feedstuff comprised control group. The other condition in test and control group was the same manner. Both groups after 40 days exposed to WSSV by oral inoculation. The clinical sign and mortality recorded for 10 days. The results showed the survival rate of exposed group was higher than the control group and it was significant (p<0/05). The result also show the mortality observed in exposed group 48 hours later than the control group. This study can led us to new methods for control of White spot disease

Multicomponent reactive transport of carbon dioxide in fluvial heterogeneous aquifers

Bureau of Economic Geolog