RESUMO
Volatile chemical products (VCP) are an increasingly important source of hydrocarbon and oxygenated volatile organic compound (OVOC) emissions to the atmosphere, and these emissions are likely to play an important role as anthropogenic precursors for secondary organic aerosol (SOA). While the SOA from VCP hydrocarbons is often accounted for in models, the formation, evolution, and properties of SOA from VCP OVOCs remain uncertain. We use environmental chamber data and a kinetic model to develop SOA parameters for 10 OVOCs representing glycols, glycol ethers, esters, oxygenated aromatics, and amines. Model simulations suggest that the SOA mass yields for these OVOCs are of the same magnitude as widely studied SOA precursors (e.g., long-chain alkanes, monoterpenes, and single-ring aromatics), and these yields exhibit a linear correlation with the carbon number of the precursor. When combined with emissions inventories for two megacities in the United States (US) and a US-wide inventory, we find that VCP VOCs react with OH to form 0.8-2.5× as much SOA, by mass, as mobile sources. Hydrocarbons (terpenes, branched and cyclic alkanes) and OVOCs (terpenoids, glycols, glycol ethers) make up 60-75 and 25-40% of the SOA arising from VCP use, respectively. This work contributes to the growing body of knowledge focused on studying VCP VOC contributions to urban air pollution.
Assuntos
Poluentes Atmosféricos , Compostos Orgânicos Voláteis , Poluentes Atmosféricos/análise , Hidrocarbonetos , Compostos Orgânicos Voláteis/análise , Terpenos , Alcanos , Aerossóis/análise , Éteres , ChinaRESUMO
We conducted an empirical study to co-design a social robot with children to bring about long-term behavioural changes. As a case study, we focused our efforts to create a social robot to promote handwashing in community settings while adhering to minimalistic design principles. Since cultural views influence design preferences and technology acceptance, we selected forty children from different socio-economic backgrounds across India as informants for our design study. We asked the children to design paper mock-ups using pre-cut geometrical shapes to understand their mental models of such a robot. The children also shared their feedback on the eight resulting different conceptual designs of minimalistic caricatured social robots. Our findings show that children had varied expectations of the robot's emotional intelligence, interactions, and social roles even though it was being designed for a specific context of use. The children unequivocally liked and trusted anthropomorphized caricatured designs of everyday objects for the robot's morphology. Based on these findings, we present our recommendations for the physical and interaction features of a minimalist social robot assimilating the children's inputs and social robot design principles grounded in prior research. Future studies will examine the children's interactions with a built prototype.
RESUMO
Utilization of waste from fish processing industry for production of value added products has attracted substantial attention. Blackspotted croaker (Protonibea diacanthus) is a marine fish having the potential of abundant supply of raw skins for production of gelatin. This study was aimed to optimize the extraction conditions for gelatin production from skin of Blackspotted croaker. Response surface methodology (RSM) was adopted by following central composite design to determine the optimal conditions of four independent variables namely concentration of NaOH (X1), soaking time (X2), extraction temperature (X3) and extraction time (X4) for three response variables namely yield, gel strength and melting point. The models obtained by RSM produced a satisfactory fit to the data with respect to gelatin extraction (for gelatin yield, R (2) = 0.867, P = 0.0003; for gel strength, R (2) = 0.837, P = 0.007; for melting point, R (2) = 0.765, P = 0.01). Based on these models, the optimum conditions to achieve the predicted maximum values were: yield of 17.21 % at X1 = 0.23 %, X2 = 46.19 min, X3 = 55.29 °C and X4 = 17.29 h; gel strength of 422.69 g at X1 = 0.22 %, X2 = 44.56 min, X3 = 59.02 °C and X4 = 15.35 h and melting point of 23.48 °C at X1 = 0.20 %, X2 = 46.68 min, X3 = 56.23 °C and X4 = 15.21 h. It can be concluded from the present study that Blackspotted croaker skin is a prospective source to produce gelatin in good yield with desirable quality attributes comparable to commercially available mammalian gelatins.
RESUMO
In view of the folklore use of green leaves to treat inflammation, the anti-inflammatory property of chlorophylls and their degradation products were studied. Chlorophyll a and pheophytin a (magnesium-free chlorophyll a) from fresh leaves showed potent anti-inflammatory activity against carrageenan-induced paw edema in mice and formalin-induced paw edema in rats. Chlorophyll a inhibited bacterial lipopolysaccharide-induced TNF-α (a pro-inflammatory cytokine) gene expression in HEK293 cells, but it did not influence the expression of inducible nitric acid synthase and cyclooxygenase-2 genes. Chlorophyll b only marginally inhibited both inflammation and TNF-α gene expression. But both chlorophyll a and chlorophyll b showed the same level of marginal inhibition on 12-O-tetradecanoyl-phorbol-13-acetate-induced NF-κB activation. Chlorophylls and pheophytins showed in vitro anti-oxidant activity. The study shows that chlorophyll a and its degradation products are valuable and abundantly available anti-inflammatory agents and promising for the development of phytomedicine or conventional medicine to treat inflammation and related diseases.