50 research outputs found
More Crop and Profit per Drop of Water: Drip Irrigation for Empowering Distressed Small Farmers
Improved Oxygen Reduction Reaction Catalyzed by Pt/Clay/Nafion Nanocomposite for PEM Fuel Cells
A novel Pt nanoparticle (Pt NP) embedded aminoclay/Nafion
(Pt/AC/N)
nanocomposite catalyst film was prepared for oxygen reduction reaction
by sol–gel method. The prepared nanocomposite films were surface
characterized using XRD and TEM and thermal stability was studied
by TGA. The prepared film has firmly bound Pt NP and could exhibit
an improved electro-reduction activity compared to vulcan carbon/Nafion
supported Pt NP (Pt/VC/N). Moreover, the Pt/AC/N film possessed good
stability in the acidic environment. The limiting current density
of the Pt/AC/N film with 35.4 μg/cm<sup>2</sup> of Pt loading
was found to be 4.2 mA/cm<sup>2</sup>, which is 30% higher than that
of the Pt/VC/N. The maximum H<sub>2</sub>O<sub>2</sub> intermediate
formation was found to be ∼1.6% and the reaction found to follow
a four electron transfer mechanism. Accelerated durability test for
2000 potential cycles showed that ca. 78% of initial limiting current
was retained. The results are encouraging for possible use of the
Pt/AC/N as the free-standing electrocatalyst layer for polymer electrolyte
membrane fuel cells
Probing the Mechanism of Isonitrile Formation by a Non-Heme Iron(II)-Dependent Oxidase/Decarboxylase
The isonitrile moiety is an electron-rich functionality that decorates various bioactive natural products isolated from diverse kingdoms of life. Isonitrile biosynthesis was restricted for over a decade to isonitrile synthases, a family of enzymes catalyzing a condensation reaction between l-Trp/l-Tyr and ribulose-5-phosphate. The discovery of ScoE, a non-heme iron(II) and α-ketoglutarate-dependent dioxygenase, demonstrated an alternative pathway employed by nature for isonitrile installation. Biochemical, crystallographic, and computational investigations of ScoE have previously been reported, yet the isonitrile formation mechanism remains obscure. In the present work, we employed in vitro biochemistry, chemical synthesis, spectroscopy techniques, and computational simulations that enabled us to propose a plausible molecular mechanism for isonitrile formation. Our findings demonstrate that the ScoE reaction initiates with C5 hydroxylation of (R)-3-((carboxymethyl)amino)butanoic acid to generate 1, which undergoes dehydration, presumably mediated by Tyr96 to synthesize 2 in a trans configuration. (R)-3-isocyanobutanoic acid is finally generated through radical-based decarboxylation of 2, instead of the common hydroxylation pathway employed by this enzyme superfamily
Variational iterative method: an appropriate numerical scheme for solving system of linear Volterra fuzzy integro-differential equations
Economics of Subsidies in a Welfare State: Dynamics of Populist Policies and Farm Profitability
The New York Times and Wall Street Journal: Does Their Coverage of Earnings Announcements Cause 'Stale' News to Become 'New' News?
Financial Feasibility of Water Conservation in Agriculture
Global water use for food production needs to be reduced to remain within planetary boundaries, yet the financial feasibility of crucial measures to reduce water use is poorly quantified. Here, we introduce a novel method to compare the costs of water conservation measures with the added value that reallocation of water savings might generate if used for expansion of irrigation. Based on detailed water accounting through the use of a high‐resolution hydrology‐crop model, we modify the traditional cost curve approach with an improved estimation of demand and increasing marginal cost per water conservation measure combination, adding a correction to control for impacts on downstream water availability. We apply the method to three major river basins in the Indo‐Gangetic plain (Indus, Ganges and Brahmaputra), a major global food producing region but increasingly water stressed. Our analysis shows that at basin level only about 10% (Brahmaputra) to just over 20% (Indus and Ganges) of potential water savings would be realized; the equilibrium price for water is too low to make the majority of water conservation measures cost effective. The associated expansion of irrigated area is moderate, about 7% in the Indus basin, 5% in the Ganges and negligible in the Brahmaputra, but farmers' gross profit increases more substantially, by 11%. Increasing the volumetric cost of irrigation water influences supply and demand in a similar way and has little influence on water reallocation. Controlling for the impact on return flows is important and more than halves the amount of water available for reallocation