Nature and electronic properties of Y-junctions in CNTs and N-doped CNTs obtained by the pyrolysis of organometallic precursors

Carbon nanotubes (CNTs) and N-doped CNTs with Y-junctions have been prepared by the pyrolysis of nickelocene-thiophene and nickel phthalocyanine-thiophene mixtures, respectively, the latter being reported for the first time. The junctions are free from the presence of sulfur and contain only carbon or carbon and nitrogen. The electronic properties of the junction nanotubes have been investigated by scanning tunneling microscopy. Tunneling conductance measurements reveal rectifying behavior with regions of coulomb blockade, the effect being much larger in the N-doped junction nanotubes

Towards Learning-Based Distributed Task Allocation Approach for Multi-Robot System

This paper introduces a novel application of Graph Convolutional Networks (GCNs) for enhancing the efficiency of the Consensus-Based Bundle Algorithm (CBBA) in multi-robot task allocation scenarios. The proposed approach in this research lies in the integration of a learning-based strategy to approximate the heuristic methods traditionally used for scoring in the CBBA framework. By employing GCNs, the proposed methodology aims to learn and predict the score function, which is crucial for task allocation decisions in multi-robot systems. This approach not only streamlines the allocation process but also potentially improves the accuracy and efficiency of task distribution among robots. The paper presents a detailed exploration of how GCNs can be effectively tailored for this specific application, along with results demonstrating the advantages of this learning-based approach over conventional heuristic methods in various simulated multi-robot task allocation scenarios

Breeding high-iron pearl millet cultivars: present status and future prospects

Micronutrient malnutrition, widespread in resource poor families in the developing world where large populations rely on cereals as staple food, has emerged as a major health challenge. Over 60% and 30% of the world’s populations are deficient in iron (Fe) and zinc (Zn), respectively1. About 80% of pregnant women and 70% children are reported to suffer from Fe deficiency, while 52% children (<5 years) have stunted growth in India2,3. Biofortification is a cost-effective and sustainable agricultural approach to deliver essential micronutrients through staple foods. Pearl millet is an important staple food in the arid and semi-arid regions of Asia and Africa. The primary focus of HarvestPlus-supported pearl millet biofortification research at ICRISAT is on improving Fe density with Zn density as an associated trait..

Development of mobile sensors for estimation of grain qualities and contaminants to enhance nutrition and safety of grain-products in developing countries; current status

The governments of several developing countries responded to their population “malnutrition crisis” (P.Webb et al., 2018), among others, by promotion of crops of high nutritional value and their enhanced usage for food products formulations (e.g. “Millet Mission” in India or “Blending Policy” in Kenya). Simultaneously, several CGIAR crop improvement programs-initiated the development of nutritionally enhanced crop cultivars (e.g. ICRISAT, CIAT, IIT). In developing countries, the promotion of novel cultivars is generally a slow and tedious process, especially if the improved grain (quantity or quality) doesn’t ultimately result in the economic incentives (e.g. the market price). Thus far, there is no economic advantage directly linked to the trade of bio-fortified crop cultivars in developing countries which does prevents their accelerated adoption. This may change if/once the necessary information on a crops value is enabled

Iniadi pearl millet germplasm as a valuable genetic resource for high grain iron and zinc densities

Crop biofortification is increasingly being recognized as a cost-effective and sustainable approach to address the widespread micronutrient malnutrition arising from Fe and Zn deficiencies. Pearl millet as a cereal crop species has higher Fe density than all other major cereals. Earlier studies in pearl millet have shown that breeding lines, hybrid parents, improved populations and composites having high Fe and Zn densities were often based largely or entirely on iniadi pearl millet germplasm. In an attempt to identify additional sources of high Fe density in this group of germplasm, 297 accessions were screened using Perl's Prussian Blue staining, of which 191 accessions (118 from Togo, 62 from Ghana and 11 from Burkina Faso) were re-evaluated during the 2010 rainy and 2012 summer seasons using the inductively coupled plasma atomic emission spectroscopy method. On the basis of the mean performance over the two seasons (environments), large variability was observed for both Fe (51–121 mg/kg) and Zn (46–87 mg/kg) densities. There was a highly significant and positive correlation between the two micronutrients (r= 0.77, P< 0.01). Of these re-evaluated accessions, 49% had higher Fe density than the high-Fe control commercial cultivar ICTP 8203 (81 mg/kg), and most of these accessions also had Zn density ≥ 61 mg/kg (59 mg/kg for ICTP 8203). A total of 27 accessions (20 from Togo and seven from Ghana) having a Fe density of 95–121 mg/kg (1 standard error of difference above that for ICTP 8203) and a Zn density of 59–87 mg/kg were selected as a valuable germplasm resource for genetic improvement of these two micronutrients in pearl millet

Dislocation Driven Chromium Precipitation in Fe-9Cr Binary Alloy: A Positron Lifetime Study

The influence of initial heat treatment on anomalous Cr precipitation within high temperature solubility region in Fe-9Cr alloy has been investigated using positron lifetime studies. Air-quenched samples with pre-existing dislocations exhibited a distinct annealing stage in positron lifetime between 800 and 1100 K corresponding to Cr-precipitation. During this stage, Transmission Electron Microscopy showed fine precipitates of average size 4 nm, dispersed throughout the sample and from EDS analysis they are found to be Cr-enriched. The existence of dislocations is found to be responsible for Cr precipitation.Comment: Revised version Submitted to Phys. Rev.

A Study of the Formation of Single- and Double-Walled Carbon Nanotubes by a CVD Method

The reduction in H2/CH4 atmosphere of aluminum-iron oxides produces metal particles small enough to catalyze the formation of single-walled carbon nanotubes. Several experiments have been made using the same temperature profile and changing only the maximum temperature (800-1070 °C). Characterizations of the catalyst materials are performed using notably 57Fe Mo¨ssbauer spectroscopy. Electron microscopy and a macroscopical method are used to characterize the nanotubes. The nature of the iron species (Fe3+, R-Fe, ç-Fe-C, Fe3C) is correlated to their location in the material. The nature of the particles responsible for the high-temperature formation of the nanotubes is probably an Fe-C alloy which is, however, found as Fe3C by postreaction analysis. Increasing the reduction temperature increases the reduction yield and thus favors the formation of surface-metal particles, thus producing more nanotubes. The obtained carbon nanotubes are mostly single-walled and double-walled with an average diameter close to 2.5 nm. Several formation mechanisms are thought to be active. In particular, it is shown that the second wall can grow inside the first one but that subsequent ones are formed outside. It is also possible that under given experimental conditions, the smallest (<2 nm) catalyst particles preferentially produce double-walled rather than single-walled carbon nanotubes