1,721,229 research outputs found
Low-temperature heat capacity and thermodynamic functions of nano Fe
No full textThe size of nano Fe powders was determined to be 25 nm in diameter by SEM. The isobaric molar heat capacity C-p of the nano Fe was measured with the high precision adiabatic low-temperature calorimeter in the temperature range from 84 K to 350 K. The relationship of C-p with temperature T was established as
Study on the Properties of Microwave Curing Epoxy Resin/Nano-Fe Composite Materials
No full textNano-Fe particles were selected as microwave-absorber, and added in the epoxy resin. Epoxy resin/nano-Fe composite materials were cured by microwave irradiation and heating. Vector network analysis, dynamic mechanical analysis(DMA) and scanning electron microscope(SEM) were used to study the curing behaviors of composite materials under the different curing ways. Results show that the dielectric constant(εr) and the dielectric loss factor(tanδ) of the epoxy resin increased obviously when nano-Fe particles were added, and microwave absorption properties of epoxy resin/nano-Fe composite materials improved greatly with increasing contents of nano-Fe particles. DMA results indicate that the storage modulus (E’) and glass transition temperature(Tg) of epoxy resin samples with nano-Fe particles were higher than those without nano-Fe particles. The microstructure and phase composition of the samples were studied by SEM and EDX. Results show that nano-Fe particles were homogeneously dispersed in the epoxy resin matrix under microwave irradiation, which implies improved strength and toughness of epoxy resin/nano-Fe composite materials.</jats:p
Investigation of mechanical properties and cure behavior of DGEBA/nano-Fe 2O 3 with polyamine dendrimer
No full textThe preparation of epoxy/iron (III) oxide nanoparticles (nano-Fe 2O 3) and studying the effect of nano-Fe 2O 3 on improving mechanical and thermal characteristics of the epoxy matrix, is highlighted in this work. Epoxy nanocomposites are prepared by dispersing nano-Fe 2O 3 in diglycidyl ether of bisphenol A (DGEBA) and, subsequently, cross-linking by using polypropylenimine octaamine dendrimer (PPOD) as curing agent with low volatility. Preparation of epoxy/nano-Fe 2O 3 nanocomposites are carried out for different concentrations (0, 1, 5, 10 and 15%) of nano-Fe 2O 3. The mechanical experiments showed that the nano-Fe 2O 3 increasing from 0% to 10% led to an increase and 15% of nano-Fe 2O 3 led to a decrease in the tensile properties. Curing reaction kinetics of DGEBA/10% nano-Fe 2O 3 with PPOD was investigated by DSC at dynamic mode. A two-parameter (m, n) autocatalytic model (Sestak-Berggren equation) was found to be the most adequate selected kinetic model. The dynamic curing behavior of DGEBA/PPOD/10% nano-Fe 2O 3 could be described by α/t=7. 1×10 9exp(-57,230/RT)( 1-α)0.82α0.41. © 2012 Elsevier Ltd. All rights reserved
Correlation network among the different sources and rates of nano and chelated Fe fertilization based on phytochemical concentrations in tomato fruits [Cont: Control; NFe10: Nano Fe (10 mg/L); NFe10: Nano Fe (20 mg/L); NFe40: Nano Fe (40 mg/L); CFe10: Chelated Fe (10 mg/L); CFe10: Chelated Fe (20 mg/L); and CFe40: Chelated Fe (40 mg/L)].
No full textCorrelation network among the different sources and rates of nano and chelated Fe fertilization based on phytochemical concentrations in tomato fruits [Cont: Control; NFe10: Nano Fe (10 mg/L); NFe10: Nano Fe (20 mg/L); NFe40: Nano Fe (40 mg/L); CFe10: Chelated Fe (10 mg/L); CFe10: Chelated Fe (20 mg/L); and CFe40: Chelated Fe (40 mg/L)].</p
Highly Efficient Utilization of Nano-Fe(0) Embedded in Mesoporous Carbon for Activation of Peroxydisulfate
No full textNanoscale
zerovalent iron (nZVI) particles have received much attention
in environmental science and technology due to their unique electronic
and chemical properties. However, the aggregation and oxidation of
nZVI brings much difficulty in practical application of environmental
remediation. In this study, we reported a composite nano-Fe(0)/mesoporous
carbon by a chelation-assisted coassembly and carbothermal reduction
strategy. Nano-Fe(0) particles with surface iron oxide (Fe2O3·FeO) were wrapped with graphitic layers which
were uniformly dispersed in mesoporous carbon frameworks. The unique
structure made the nano-Fe(0) particles stable in air for more than
20 days. It was used as a peroxydisulfate (PDS) activator for the
oxidation treatment of 2,4,6-trichlorophenol (TCP). The TOF value
of MCFe for TCP degradation is nearly 3 times higher than those of
FeSO4 and Fe2O3·FeO and nearly
2 times than that of commercial nZVI. The reactive oxygen species
(ROS) including •SO4–, HO•,
and •O2–, 1O2 are efficiently generated by PDS activation with MCFe. The PDS activation
process by nano-Fe(0) particles was intrinsically induced by the ferrous
ions (Fe(II)) continuously generated at the solid/aqueous interface.
Namely, the nano-Fe(0) particles were highly efficiently utilized
in sulfate radical-based advanced oxidation processes (SR-AOP). The
porous structure also assists the absorption and transfer of TCP during
the degradation process
Uptake and biological responses to nano-Fe versus soluble FeCl3 in excised mussel gills
No full text10 pages, 7 figures, 2 tablesNano-Fe particle uptake was experimentally examined in vitro using excised gills and blood cells of the edible blue mussel Mytilus sp. Whole gills were exposed to both Fe(2)O(3) nanoparticles and a solution of the hydrated FeCl(3) salt, for up to 12 h, and blood cells for 30 min. Equimolar Fe(+3) in the nano- and the soluble form was estimated under the assumption of dense spherical particles accommodating the same number of Fe(+3) as in the dissolved salt solution, namely: 1,000 microg L(-1) Fe(2)O(3) equivalent to 100 microg L(-1) FeCl(3).6H(2)O. Putative toxic impact of nano-Fe in gill epithelia and blood cells was assessed by an array of techniques including light- and electron microscopy, biomarkers for oxidative stress (lipid peroxidation levels), neurotoxic effects (acetylcholinesterase activity) and cytotoxicity (neutral red retention). Total and filtered fractions (20 and 200 nm, respectively) of Fe were analysed by ICP-OES. Our results provide evidence for the following: (1) much of both the soluble (95%) and the nano-Fe (90%) were removed from the water column within 12 h; (2) dissolved- and nano-Fe seemed to follow different routes of uptake within the gill epithelium; (3) both nano-Fe and soluble FeCl(3) caused similar impairment of lysosomal stability in circulating blood cells; (4) lipid peroxidation in gills exposed to the two distinct forms of Fe was increased, while acetylcholinesterase activity was unaffected. In these short-term in vitro studies, there appears to be little difference in toxic response between exposure to the Fe salt and the nano-Fe indicating that, in this case, the nanoparticles do not invoke special properties affecting biological function in gills. However, with the use of nano-Fe as a food additive, clearly longer-term in vivoPeer reviewe
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Investigation of mechanical properties and cure behavior of DGEBA/nano-Fe 2O 3 with polyamine dendrimer
No full textInvestigation of mechanical properties and cure behavior of DGEBA/nano-Fe 2O 3 with polyamine dendrime
Nano-Fe/Cu particles for the remediation of cesium contaminated solutions
No full textThe great East Japan Earthquake in 2011 triggered the Fukushima Daiichi nuclear power plant accident. Large amount of cesium was released into the environment following this severe accident. Therefore, this research work evaluated the applicability of nano-Fe/Cu particles for the removal of cesium from contaminated waters for the first time. Cesium removal was investigated using batch technique with respect to initial cesium concentration, contact time, temperature, pH, competing cations and dosage of nanoparticles. The results showed that nano-Fe/Cu particles demonstrated effective performance for removal of cesium. The removal efficiency exceeded 99% at initial cesium concentration of 1 mg/L and 1 g/L dose. The removal of cesium was largely depending on the solution pH and temperature. The current study proved the potential utility of the nano-Fe/Cu particles as a promising adsorbent for the treatment of waters containing cesium
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