FUEL SYNTHESIS OF SYNGAS USING HYDROTALCITE DERIVED CATALYST

This project investigates the fuel synthesis from syngas using hydrotalcite derived catalyst. The focus of this research is syngas conversion into methanol as an alternative source of fuel. Hydrotalcite derived catalyst was used as it is flexible to reform its structure and have been demonstrated its best performances as catalyst. The range of hydrotalcite derived catalyst will be prepared via co-precipitation method with the aid of metal precursors of nickel, zinc with alumina as support. Hydrotalcite derived catalyst of Ni-Al, Zn-Al and Ni-Zn-Al will be tested throughout this study. The physicochemical and catalytic properties of catalysts was studied usingRAMAN Spectroscopy method, Brunauer-Emmett-Teller (BET) method and Field Emission Scanning Electron Microscopy (FESEM). Catalytic performance of synthesized catalyst was tested using a hydrocarbon cracking reactor to synthesize syngas into methanol. The desired temperature and pressure for this project was fixed at 200℃ and 2 bar respectively. From the overall catalytic reaction, it proves that Zn-Ni-Al has the highest yield of methanol production compared to 2 other bimetallic catalysts. Thecomposition of feed gas used was CO/H2/N2used was 35/45/20

Plant regeneration from axillary bud derived callus in white yam (Dioscorea rotundata)

Published online: 14 June 2016Dioscorea rotundata, commonly known as white yam, is an important staple food crop widely cultivated in West Africa and provides food security to millions of people. Genetic improvements of this crop using the advanced biotechnology tools have been hampered hitherto by the recalcitrant nature of regeneration through somatic embryogenesis. Therefore, we have developed an efficient and reproducible system for plant regeneration via somatic embryogenesis. Explants of different types (immature leaf, node, stem internode, root segment, petiole, and axillary bud) of D. rotundata accession TDr 2436 were tested for their embryogenic potentials on Murashige and Skoog (MS) medium supplemented with various auxins (2,4-D, NAA, and picloram). Among all explants tested, axillary bud explants cultured on MS medium supplemented with picloram (0.5–12 mg/l) favored the production of calli. Maximum proliferation of calli (526 mg fresh weight/explant) was achieved on MS medium supplemented with picloram (0.5 mg/l), casein hydrolysate (600 mg/l), and proline (1 g/l). Histology analysis confirmed that the embryogenic calli produced on this medium were mixed with non-embryogenic calli. Transfer of calli on MS basal medium supplemented with activated charcoal (1 %) changed the color of calli to purple and promoted the production of somatic embryos (87 embryos/callus) as well as adventitious shoot buds. Furthermore, upon transfer to MS medium supplemented with BAP (0.4 mg/l), the embryos continued their differentiation and maturation and germinated into complete plantlets. The adventitious shoot buds produced multiple shoots on MS medium supplemented with BAP (0.4 mg/l). Well-developed germinated plantlets were acclimatized in the screen house with 90 % survivability. Histology studies confirmed that the regeneration of D. rotundata reported here followed dual regeneration pathways. The embryogenic calli regenerated through development of somatic embryos and germinated into complete plantlets, however non-embryogenic calli regenerated through organogenesis and developed multiple shoots. The developed protocol has potential for somatic hybridization, mass clonal propagation, and genetic transformation applications

Agrobacteriummediated genetic transformation of yam (Dioscorea rotundata): an important tool for functional study of genes and crop improvement

Published online: 15 Sep 2014Although genetic transformation of clonally propagated crops has been widely studied as a tool for crop improvement and as a vital part of the development of functional genomics resources, there has been no report of any existing Agrobacterium-mediated transformation of yam (Dioscorea spp.) with evidence of stable integration of T-DNA. Yam is an important crop in the tropics and subtropics providing food security and income to over 300 million people. However, yam production remains constrained by increasing levels of field and storage pests and diseases. A major constraint to the development of biotechnological approaches for yam improvement has been the lack of an efficient and robust transformation and regeneration system. In this study, we developed an Agrobacterium-mediated transformation of Dioscorea rotundata using axillary buds as explants. Two cultivars of D. rotundata were transformed using Agrobacterium tumefaciens harboring the binary vectors containing selectable marker and reporter genes. After selection with appropriate concentrations of antibiotic, shoots were developed on shoot induction and elongation medium. The elongated antibiotic-resistant shoots were subsequently rooted on medium supplemented with selection agent. Successful transformation was confirmed by polymerase chain reaction, Southern blot analysis, and reporter genes assay. Expression of gusA gene in transgenic plants was also verified by reverse transcription polymerase chain reaction analysis. Transformation efficiency varied from 9.4 to 18.2% depending on the cultivars, selectable marker genes, and the Agrobacterium strain used for transformation. It took 3–4 months from Agro-infection to regeneration of complete transgenic plant. Here we report an efficient, fast and reproducible protocol for Agrobacterium-mediated transformation of D. rotundata using axillary buds as explants, which provides a useful platform for future genetic engineering studies in this economically important crop

Spontaneous Interlayer Charge Transfer near the Magnetic Quantum Limit

Experiments reveal that a confined electron system with two equally-populated layers at zero magnetic field can spontaneously break this symmetry through an interlayer charge transfer near the magnetic quantum limit. New fractional quantum Hall states at unusual total filling factors such as \nu = 11/15 (= 1/3 + 2/5) stabilize as signatures that the system deforms itself, at substantial electrostatic energy cost, in order to gain crucial correlation energy by "locking in" separate incompressible liquid phases at unequal fillings in the two layers (e.g., layered 1/3 and 2/5 states in the case of \nu = 11/15).Comment: 4 pages, 4 figures (1 color) included in text. Related papers at http://www.ee.princeton.edu/~hari/papers.htm

Multiwavelength Study on Solar and Interplanetary Origins of the Strongest Geomagnetic Storm of Solar Cycle 23

We study the solar sources of an intense geomagnetic storm of solar cycle 23 that occurred on 20 November 2003, based on ground- and space-based multiwavelength observations. The coronal mass ejections (CMEs) responsible for the above geomagnetic storm originated from the super-active region NOAA 10501. We investigate the H-alpha observations of the flare events made with a 15 cm solar tower telescope at ARIES, Nainital, India. The propagation characteristics of the CMEs have been derived from the three-dimensional images of the solar wind (i.e., density and speed) obtained from the interplanetary scintillation data, supplemented with other ground- and space-based measurements. The TRACE, SXI and H-alpha observations revealed two successive ejections (of speeds ~350 and ~100 km/s), originating from the same filament channel, which were associated with two high speed CMEs (~1223 and ~1660 km/s, respectively). These two ejections generated propagating fast shock waves (i.e., fast drifting type II radio bursts) in the corona. The interaction of these CMEs along the Sun-Earth line has led to the severity of the storm. According to our investigation, the interplanetary medium consisted of two merging magnetic clouds (MCs) that preserved their identity during their propagation. These magnetic clouds made the interplanetary magnetic field (IMF) southward for a long time, which reconnected with the geomagnetic field, resulting the super-storm (Dst_peak=-472 nT) on the Earth.Comment: 24 pages, 16 figures, Accepted for publication in Solar Physic

Multi-Wavelength View of Flare Events on November 20, 2003

We analyze two flare events which occurred in active region NOAA 501 on November 20, 2003. The H-alpha and magnetogram measurements show interaction between two filaments which produced a slowly rising flare event, corresponding to two stages of magnetic reconnection. The relative clockwise rotation between the two sunspot systems caused filament destabilization. The cusp-shaped magnetic field in the main phase of the second flare and its evolution in correlation with ribbon separation provide evidence for the cause of the CME eruption. The propagation and orientation of the CME with respect to the ecliptic plane is illustrated by IPS images.Comment: 4 pages, 4 figures; To appear in "Magnetic Coupling between the Interior and the Atmosphere of the Sun", eds. S.S. Hasan and R.J. Rutten, Astrophysics and Space Science Proceedings, Springer-Verlag, Heidelberg, Berlin, 200

Kondo Effect and Surface-State Electrons

We have used low temperature scanning tunneling spectroscopy and atomic manipulation to study the role of surface-state electrons in the Kondo effect of an isolated cobalt atom adsorbed on Ag(111). We show that the observed Kondo signature remains unchanged in close proximity of a monoatomic step, where the local density of states of the surface-state electrons is strongly perturbed. This result indicates a minor role for surface-state electrons in the Kondo effect of cobalt, compared to bulk electrons. A possible explanation for our findings is presented.Comment: 4 pages, 4 figures, ACSIN-7 proceeding

Random sequential adsorption of spheres on a cylinder

Inspired by observations of beads packed on a thin string in such systems as sea-grapes and dental plaque, we study the random sequential adsorption of spheres on a cylinder. We determine the asymptotic fractional coverage of the cylinder as a function of the sole parameter in the problem, the ratio of the sphere radius to the cylinder radius (for a very long cylinder) using a combination of analysis and numerical simulations. Examining the asymptotic structures, we find weak chiral ordering on sufficiently small spatial scales. Experiments involving colloidal microspheres that can attach irreversibly to a silica wire via electrostatic forces or DNA hybridization allow us to verify our predictions for the asymptotic coverage

Scattering Theory of Kondo Mirages and Observation of Single Kondo Atom Phase Shift

We explain the origin of the Kondo mirage seen in recent quantum corral Scanning Tunneling Microscope (STM) experiments with a scattering theory of electrons on the surfaces of metals. Our theory combined with experimental data provides the first direct observation of a single Kondo atom phase shift. The Kondo mirage at the empty focus of an elliptical quantum corral is shown to arise from multiple electron bounces off the walls of the corral in a manner analagous to the formation of a real image in optics. We demonstrate our theory with direct quantitive comparision to experimental data.Comment: 13 pages; significant clarifications of metho

Theory of STM Spectroscopy of Kondo Ions on Metal Surfaces

The conduction electron density of states nearby a single magnetic impurity, as measured recently by scanning tunneling microscopy (STM), is calculated. It is shown that the Kondo effect induces a narrow Fano resonance as an intrinsic feature in the conduction electron density of states. The line shape varies with the distance between STM tip and impurity, in qualitative agreement with experiments, and is sensitive to details of the band structure. For a Co impurity the experimentally observed width and shift of the Kondo resonance are in accordance with those obtained from a combination of band structure and strongly correlated calculations.Comment: 5 pages, 4 figures, presented at the NATO Advanced Research Workshop on "Size Dependent Magnetic Scattering", Pecs, Hungary, May 28 - June 1, 200