55 research outputs found
Cogranulation of low rates of graphene and graphene oxide with macronutrient fertilizers remarkably improves their physical properties
Published: November 20, 2017The beneficial effects of graphene (GN) and graphene oxide (GO) additives on the physical properties of monoammonium phosphate (MAP) fertilizer granules were investigated. Low doses (0.05 to 0.5% w/w) of GN and GO sheets were cogranulated with MAP and effects on the crushing strength, abrasion and impact resistance of prepared granules were evaluated. Cogranulation with 0.5% w/w GN sheets (MAP-GN) significantly enhanced the mechanical strength of MAP granules (∼18 times improvement) whereas inclusion of same amounts of GO sheets (MAP-GO) improved the strength to a lesser extent (∼8 times improvement). The cogranulation of GN also improved MAP granules resistance to abrasion (>70%) and impact resistance (>75%). Heating MAP-GO granules at 50 °C after granulation is shown to enhance their physical properties in comparison to MAP-GO granules dried under ambient temperatures. The advantages of GN and GO sheets compared with current additives in enhancing the physical properties of MAP granules are explained by their high specific area, superior nanofiller–matrix and adhesion/interlocking ability arising from their unique wrinkled structures and two-dimensional (2D) geometry. These results confirm the potential of GN/GO additives to enhance the physical properties of MAP granules that could be translated to other fertilizers and applied in the industry.Shervin Kabiri, Roslyn Baird, Diana N. H. Tran, Ivan Andelkovic, Mike J. McLaughlin, and Dusan Losi
Graphene oxide-Fe(III) composite containing phosphate - a novel slow release fertilizer for improved agriculture management
Novel materials offer opportunities to develop new types of fertilizers which could potentially increase efficiency of nutrient use in agriculture. Slow-release fertilizers can be more effective than traditional nutrient sources and simultaneously reduce negative impacts of nutrients to the environment. Using low-cost, abundant natural material, graphite rock, a functionalized graphene oxide (GO)/iron (GO-Fe) composite was synthetised and examined as a new carrier of phosphate ions in order to improve nutrient delivery to plants. The morphology of the composite was examined with scanning electron microscopy (SEM), and X-ray diffraction (XRD) was used to determine the presence of crystal phases. The composite was also characterised with thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR). We found that the presence of ferric ions was responsible for attachment of phosphate ions onto the GO-Fe composite, providing a loading capacity of 48 mg P/g. The kinetics of P release were examined using a column perfusion test while P diffusion in three different types of soils was examined using a visualization technique and chemical analysis. Compared with commercial monoammonium phosphate (MAP) fertilizer, application of GO-Fe composite loaded with phosphate (GO-Fe-P) resulted in slower release of P, thus reducing the possibility for leaching or runoff of soluble P to surface and groundwaters.Ivan B. Andelkovic, Shervin Kabiri, Ehsan Tavakkoli, Jason K. Kirby, Michael J. McLaughlin, Dusan Losi
Engineered phosphate fertilisers with dual-release properties
A new strategy to produce phosphate (P) fertilizers with both fast and slowly soluble P by the compaction method to produce composite products is presented. This unique composition is created by combining monoammonium phosphate (MAP) as a highly soluble P nutrient source, with a commercially available slow-release P such as struvite (Str) or P-loaded graphene oxide (GO). Graphene oxide-loaded P was synthesized by in situ oxidation of GO and ferrous ion (GO-Fe) mixtures with hydrogen peroxide and further loading of P onto the GO-Fe composite. The nutrient release in water was studied for dual-release MAP-Str and MAP-GO-Fe-P and compared to their corresponding slow- and fast-release sources. Column perfusion experiments showed a biphasic dissolution behavior with no significant difference between MAP-GO-Fe-P and MAP-Str. Visualization of P diffusion and chemical analysis of the soil after diffusion were used to assess the diffusion of P from different P fertilizers in various types of soil. Runoff and leaching simulations were performed to investigate the effects of the prepared fertilizer formulations on the environment. Overall, the diffusion of the dual-release fertilizers and the P loss in runoff and leaching experiments were less than for MAP. The better environmental performance of the dual-release fertilizers compared to MAP was related to the specific properties of the GO-based materials such as their two-dimensional structure and to the low solubility of the Str in the case of Str-based fertilizers.Shervin Kabiri, Ivan B. Andelkovic, Rodrigo C. da Silva, Fien Degryse, Roslyn Baird, Ehsan Tavakkoli, Dusan Losic, and Michael J. McLaughli
Improved accuracy of in-ring laser spectroscopy by in-situ electron cooler voltage measurement
Ratings of age of acquisition of 299 words across 25 languages: Is there a cross-linguistic order of words?
We present a new set of subjective age-of-acquisition (AoA) ratings for 299 words (158 nouns, 141 verbs) in 25 languages from five language families (Afro-Asiatic: Semitic languages; Altaic: one Turkic language: Indo-European: Baltic, Celtic, Germanic, Hellenic, Slavic, and Romance languages; Niger-Congo: one Bantu language; Uralic: Finnic and Ugric languages). Adult native speakers reported the age at which they had learned each word. We present a comparison of the AoA ratings across all languages by contrasting them in pairs. This comparison shows a consistency in the orders of ratings across the 25 languages. The data were then analyzed (1) to ascertain how the demographic characteristics of the participants influenced AoA estimations and (2) to assess differences caused by the exact form of the target question (when did you learn vs. when do children learn this word); (3) to compare the ratings obtained in our study to those of previous studies; and (4) to assess the validity of our study by comparison with quasi-objective AoA norms derived from the MacArthur–Bates Communicative Development Inventories (MB-CDI). All 299 words were judged as being acquired early (mostly before the age of 6 years). AoA ratings were associated with the raters’ social or language status, but not with the raters’ age or education. Parents reported words as being learned earlier, and bilinguals reported learning them later. Estimations of the age at which children learn the words revealed significantly lower ratings of AoA. Finally, comparisons with previous AoA and MB-CDI norms support the validity of the present estimations. Our AoA ratings are available for research or other purposes
Scholarly publishing depends on peer reviewers
The peer-review crisis is posing a risk to the scholarly peer-reviewed journal system. Journals have to ask many potential peer reviewers to obtain a minimum acceptable number of peers accepting reviewing a manuscript. Several solutions have been suggested to overcome this shortage. From reimbursing for the job, to eliminating pre- publication reviews, one cannot predict which is more dangerous for the future of scholarly publishing. And, why not acknowledging their contribution to the final version of the article published? PubMed created two categories of contributors: authors [AU] and collaborators [IR]. Why not a third category for the peer-reviewer
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