12 research outputs found
Helping feed the world with rice innovations: CGIAR research adoption and socioeconomic impact on farmers
Rice production has increased significantly with the efforts of international research centers and national governments in the past five decades. Nonetheless, productivity improvement still needs to accelerate in the coming years to feed the growing population that depends on rice for calories and nutrients. This challenge is compounded by the increasing scarcity of natural resources such as water and farmland. This article reviews 17 ex-post impact assessment studies published from 2016 to 2021 on rice varieties, agronomic practices, institutional arrangements, information and communication technologies, and post-harvest technologies used by rice farmers. From the review of these selected studies, we found that stress-tolerant varieties in Asia and Africa significantly increased rice yield and income. Additionally, institutional innovations, training, and natural resource management practices, such as direct-seeded rice, rodent control, and iron-toxicity removal, have had a considerable positive effect on smallholder rice farmers’ economic well-being (income and rice yield). Additional positive impacts are expected from the important uptake of stress-tolerant varieties documented in several Asian, Latin American, and African countries
Effects of Posttreatments on the Storage Stability of Reclaimed Rubber
Reclaimed rubber should be considered a source of new material with an economic impact, so the recycling of waste rubber is especially important. In this paper, sulfur-cured waste tire rubber powder is successfully devulcanized in a normal-pressure continuous regeneration system under the application of an activator and aromatic oil. Then, the reclaimed rubber was subjected to further mechanical shearing using a two-roll mill, rubber extruder, and rubber strainer. The effects of the storage time at room temperature on the properties and structure of reclaimed rubber were examined by sol fraction measurement, Mooney viscosity measurement, crosslink density measurement, tensile property testing, and Rubber Process Analyzer (RPA) measurement. The results under the test conditions indicated that different postprocessing operations were not making much difference to the properties of the reclaimed rubber. But the effect of storage time is more significant; the Mooney viscosity value increased from 65 to 90 when the storage period increases to 60 days, the sol fraction decreased, and the crosslink and density storage modulus also increased with increasing storage time due to the slow recombination and aggregation of the molecular fragments with free radicals happening in the reclaimed rubber during the storage
A new approach to determine rheological percolation of carbon nanotubes in microstructured polymer matrices
We demonstrate the rheological percolation of carbon nanotubes (CNTs) in microstructured polymer matrices. Polymer/CNT composites are fabricated from polycarbonates with different molecular weights to diversify the microstructures, which vary with the polymer radius of gyration and entanglements. We propose a model for the dispersion of CNTs in polymer matrices, which explains the electrical and rheological properties. The percolation theory represented by a power-law relation cannot account for the rheological percolation of CNTs in this work. Therefore, we investigate the crossover points to provide a quantitative indication of the rheological percolation threshold of nanofillers in polymer matrices. For the first time, the rheological percolation threshold is determined experimentally with this definition. The effects of molecular weight and shear viscosity of the medium on the percolation of CNTs are demonstrated separately. © 2013 Elsevier Ltd. All rights reserved.
Carburization of stainless steel clad by uranium-plutonium carbide fuel
Carburization of stainless steel clad by the fuel in fast reactor fuel pins, containing uranium-plutonium mixed carbide, would adversely affect the mechanical properties of the clad. The extent of carburization depends on the relative carbon potentials of the fuel and the clad. The measurement of the carbon potential of stainless steel as a function of temperature in the operating range of the fuel pins was recently reported from this laboratory. The method is based on equilibration of SS specimens with liquid sodium while simultaneously monitoring the carbon potential of sodium with an electrochemical carbon meter. In the present work, the same procedure was extended to the fuel and results obtained with both UC and (U,Pu)C in the range of 840 to 960 K are reported. Using the present results and the earlier data on carbon potential of SS, the possibility of clad carburization is analysed
Development and characterizations of Ag nanoparticles decorated TiO2-ZrO2 coatings as electrode material for supercapacitors
Supercapacitors are considered as newly developed auxiliary and clean supplies of power and energy for the next generation energy storage devices with significant impact in many fields. In the present investigation, Ag nanoparticles decorated over TiO2-ZrO2 films are used as the material for energy storage applications. The cyclic voltammograms of the proposed material show better specific capacitance values and robust cyclic stability. The results of the electrochemical measurements further show a strong double-layer electrical capacitance of ternary mixed oxides. The synergetic interaction among the components in the hierarchical nanostructured porous Ag@TiO 2-ZrO2 film guaranteed the good capacitive performance. The comparison between the TiO2-ZrO2 films and Ag decorated TiO 2-ZrO2 films bring out the strong interconnection between the constitution and composition of both systems and their properties. These results underline the exceptional electrical double layer capacitive behavior that is seen in porous ternary composite films with better surface area. Furthermore, such a simple and low-cost layer by layer assembly method with self-cleaning property can be used for the large-scale fabrication of diverse functional architectures for energy storage and conversions