Design and evaluation of an inlet conditioner to dry particles for real-time particle sizers

Real-time particle sizers provide rapid information about atmospheric particles, particularly peak exposures, which may be important in the development of adverse health outcomes. However, these instruments are subject to erroneous readings in high-humidity environments when compared with measurements from filter-based, federal reference method (FRM) samplers. Laboratory tests were conducted to evaluate the ability of three inlet conditioners to dry aerosol prior to entering a real-time particle sizer for measuring coarse aerosols (Model 3321 Aerodynamic Particle Sizer, APS) under simulated highly humid conditions. Two 30 day field studies in Birmingham, AL, USA were conducted to compare the response of two APSs operated with and without an inlet conditioner to that measured with FRM samplers. In field studies, the correlation of PM(10-2.5) derived from the APS and that measured with the FRM was substantially stronger with an inlet conditioner applied (r2 ranged from 0.91 to 0.99) than with no conditioner (r2 = 0.61). Laboratory experiments confirmed the ability of the heater and desiccant conditioner to remove particle-borne moisture. In field tests, water was found associated with particles across the sizing range of the APS (0.5 microm to 20 microm) when relative humidity was high in Birmingham. Certain types of inlet conditioners may substantially improve the correlation between particulate mass concentration derived from real-time particle sizers and filter-based samplers in humid conditions.     

Catalytic co-pyrolysis of <Emphasis Type="Italic">Pterospermum acerifolium</Emphasis> and plastic waste

The continuous increase in generation of solid wastes and gradual declining of fossil fuels necessities the development of sustainable conversion technologies. Recent studies have shown that the addition of biomass with hydrogen-rich co-reactants (plastics) altogether enhances the quality of bio-fuels using pyrolysis process. It was observed that red mud (which is produced as by-product in Bayer process) was used as a catalyst in few conversion process. In this study, pyrolysis of biomass (Pterospermum acerifolium) and waste plastic mixture with activated red-mud catalyst was investigated using thermo-gravimetric analysis. The kinetic parameters (activation energy and pre-exponential factor) of this process were determined using distributed activation energy model (DAEM). The DAEM was effectively applied to decide the activation energy (E) and pre-exponential factor (A) for each sample at various conversions during the catalytic co-pyrolysis. The biomass, plastic, biomass–plastic, and biomass–plastic–catalyst exhibited activation energies in the ranges of 78–268, 172–218, 67–307, and 202–292 kJ/mol, respectively.     

High-sensitivity direct analysis of aflatoxins in peanuts and cereal matrices by ultra-performance liquid chromatography with fluorescence detection involving a large volume flow cell

This paper reports a sensitive and cost effective method of analysis for aflatoxins B1, B2, G1 and G2. The sample preparation method was primarily optimised in peanuts, followed by its validation in a range of peanut-processed products and cereal (rice, corn, millets) matrices. Peanut slurry [12.5 g peanut + 12.5 mL water] was extracted with methanol: water (8:2, 100 mL), cleaned through an immunoaffinity column and thereafter measured directly by ultra-performance liquid chromatography-fluorescence (UPLC-FLD) detection, within a chromatographic runtime of 5 minutes. The use of a large volume flow cell in the FLD nullified the requirement of any post-column derivatisation and provided the lowest ever reported limits of quantification of 0.025 for B1 and G1 and 0.01 μg/kg for B2 and G2. The single laboratory validation of the method provided acceptable selectivity, linearity, recovery and precision for reliable quantifications in all the test matrices as well as demonstrated compliance with the EC 401/2006 guidelines for analytical quality control of aflatoxins in foodstuffs.     

Coping with the ‘Indian summer’: unique nesting cycle and nest architecture of the paper wasp,Polistes wattii

The Science of Nature - Leaf-cutting ants are highly successful herbivores in the Neotropics. They forage large amounts of fresh plant material to nourish a symbiotic fungus that sustains the...     

Bioccumulation and toxicity of Cu and Cd in Vallisneria spiralis (L.)

Accumulation of Cu and Cd by Vallisneria spiralis was studied under laboratory conditions. Plants showed ability to reduce 5 µg ml^–1 Cu background concentration to below 0.05 µg ml^–1 (m.p.l., WHO 1985) within 48 h. The Cd concentration of 1.0 µg ml^–1 was reduced to below m.p.l. (0.005 µg ml^–1) in 168 h. Cysteine synthesis was more under Cd stress condition. Both the metals were toxic to the plants at higher concentrations; more in the case of Cd.NBRI Rsearch Publication No. 417 (N.S.).     

Screening of antibiotic residues in fresh milk of Kathmandu Valley,Nepal

The prevalence of two groups of antibiotics; namely penicillin and sulfonamides was studied in fresh milk available in Kathmandu Valley of Nepal. The milk samples (n = 140) were collected from three different sources; individual farmers, cottage dairies and organized dairies of Kathmandu valley. Qualitative and semi-quantitative analysis with rapid screening kits revealed that 23% samples were positive for antibiotic residues in the fresh milk for penicillin and sulfonamide groups (1–256 µg/kg). High performance liquid chromatography (HPLC) analyses detected 81% samples positive for amoxicillin (68–802 µg/kg), 41% for sulfadimethoxine (31–69 µg/kg), 27% for penicillin G (13–353 µg/kg), and 12% for ampicillin (0.5–92 µg/kg). Due to the precision and accuracy of liquid chromatography method, it detected more positive samples and consequently presented higher prevalence than the rapid screening kits. The antibiotic residues were found above the maximum residue limits that presented serious threat to consumer health and raised a serious concern regarding the implementation and monitoring of international regulations in developing countries.     

Thermodynamic modelling of bio-species accommodation

An ecological model has been constructed. A chemical analogy to the biological system has been developed, and the system's driving forces have been identified.     

Metal- and ionic liquid-based photocatalysts for biodiesel production: a review

Environmental Chemistry Letters - Diminishing petroleum reserves, increasing carbon emissions, and the&nbsp;growing demand for fuels are calling for alternative fuels. Global diesel consumption...