jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: PJSC “MMC “Norilsk Nickel”, Polar Division, Norilsk, Russia | O. V. Bol’shakova | E. V. Salimzhanova | М. Н. Нафталь | PO “NPP Kvalitet”, Moscow, Russia | Н. В. Белоусова
Source: Tsvetnye Metally (article, 2018-06-29)
Field: Chemistry — Inorganic Chemistry

The factors affecting the nickel oxide reduction Nickel powder production in a tube furnace employing available feedstock and minimum power for Ni oxide reduction is one of the promising way to cut the production costs for Ni powder used to remove Cu ions from Ni electrolyte by cementation. Recent studies carried out in Norilsk Nickel resulted in the fine-tuned Ni powder process flowsheet. Unlike ANP production technique of OJSC Kola MMC, the Polar Division flowsheet provides reagent nickel powder of proper quality with no liquid petrochemicals added in the process. It implies reduction at lower temperatures, supply of natural gas and air to the rotary tube furnace burner to maintain the required reduction temperature, use of Kayerkansky open pit coal as a reductant with higher ash content compared to coal from Bachatsky open pit used at Kola MMC. Previous investigations of Gipronickel Institute indicates that the solid reductants with lower volatiles and ash content at Kola MMC do not ensure ANP to comply with the process requirements. It can be assumed that freshly reduced nickel oxide is catalytically active towards the oxidative conversion of gaseous hydrocarbons, namely methane, while palladium present in initial nickel oxide significantly increases its catalytic activity. The critical affecting factors are as follows: Ni-Pd ratio of the initial Ni oxide, specific ratio of carbon monoxide and molecular hydrogen generated during the solid reductant oxidation and catalytic oxidative conversion of gaseous hydrocarbons into synthetic gas, temperature range of reduction. Nickel ; Reduction (mathematics) ; Nickel oxide ; Materials science ; Metallurgy ; Mathematics Pigment Synthesis and Properties
Authors: Jyotirmayee Mohanty | Raman Khurana | N. Barooah | Achikanath C. Bhasikuttan
Source: Zenodo (CERN European Organization for Nuclear Research) (article, 2018-05-01)
Field: Chemistry — Spectroscopy

Photophysical and protolytic properties of neutral red with macrocyclic receptors: Fluorescence sensor and drug delivery applications Radiation &amp; Photochemistry Division, Bhabha Atomic Research Centre, Mumbai-400 085, India Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai-400 094, India E-mail: bkac@barc.gov.in Fax: 91-22-25505151 <em>Manuscript received 19 March 2018, accepted 04 April 2018</em> Stimuli-responsive supramolecular assemblies of potential drug/guest molecules through non-covalent host-guest inter­action have gained enormous interest as they find promising in drug delivery and fluorescence sensor applications. In this review article, the supramolecular interactions of a biologically important intracellular pH indicator dye Neutral Red (NR) with three macrocyclic hosts, namely, cucurbit[7]uril (CB7), <em>p</em>-sulfonatocalix[6]arene (SCX6) and β-cyclodextrin (β-CD), having comparable cavity dimensions, have been discussed. The protonated form of neutral red interacts strongly with CB7 and SCX6 cation receptors (10<sup>5</sup>–10<sup>6</sup> M<sup>–1</sup>), whereas the neutral form interacts with β-CD. As a result, NR displays upward p<em>K</em><sub>a</sub> shift (2–2.3 units) in the presence of CB7 or SCX6 and downward p<em>K</em><sub>a</sub> shift (0.7 unit) with β-CD. The binding affinity of NR with CB7/SCX6 can be fine-tuned by addition and competitive binding of metal ions, which leads to a p<em>K</em><sub>a</sub> shift of the dye. This p<em>K</em><sub>a</sub> shift method has been exploited to relocate the dye from the macrocyclic cavity of CB7 to the biomolecular pocket of bovine serum albumin which can find applications in drug delivery. The fluorescence quenching observed in the SCX-neutral red interactions stands in contrast to the fluorescence enhance­ment observed with CB7 and β-CD. This is due to the unique portal stacking interaction of NRH<sup>+</sup> with the SCXs, compared to the axial inclusion geometry documented for CB7 and β-CD. The electron transfer from the SCX to the neutral red dye is adjudged to be the effective excited-state relaxation pathway leading to fluorescence quenching. In combination with the metal-ion induced fluorescence regeneration, the SCX-neutral red system finds potential appli­cations in drug delivery, photodynamic therapy, catalysis, and sensor applications. Fluorescence ; Chemistry ; Photochemistry ; Drug ; Pharmacology ; Medicine ; Optics ; Physics Molecular Sensors and Ion Detection ; Photochromic and Fluorescence Chemistry ; Analytical Chemistry and Sensors
Authors: Carlos Díaz Aviñó
Source: Dialnet (Universidad de la Rioja) (article, 2018-01-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Design of anisotropic nanostructures for light control The rapid theoretical and experimental advances in micro- and nanofabrication methods has currently made possible the governing of light flow with unprecedented control. Metamaterials and metasurfaces are engineered nanostructures composed by designed building blocks with the ability to manipulate light under a prescribed response. As a result, metamaterials provide a high number of novel potential applications which were previously inconceivable. This Ph.D. Thesis explores on some uses of these exceptional metamaterials, specifically to achieve optical undetectability and controlled beamshaping. The main objective of this Thesis is the proposal of new photonic structures based on metal-dielectric multilayered metamaterials, which due to their high form anisotropy are capable of generating highly localized light distributions, as well as optically inert responses in the far field. The mechanism of scattering cancellation is thoroughly analyzed in nanoparticles of cylindrical symmetry. With an accurate control of a multilayered morphology and a proper combination of materials, it is possible to fine-tune the scattering cancellation at different wavelengths to achieve invisibility. Secondly, an adequate design of a nonplanar metacoating in the nanoscale gives us the ability of achieving tight focusing of high numerical-aperture electromagnetic waves. Moreover, the use of the engineered metasurfaces may execute a beam shaping to transform wide-angle converging waves into shape-preserving accelerating beams. The work developed here is not limited exclusively to developments based on theoretical foundations and numerical simulations, but also an attempt to immerse into the experimental labor. In this direction we studied the Dyakonov surface waves (DSWs), which can be found at the interface between a birefringent medium and another isotropic medium. The excitation occurs in the near field under photoluminescence, and the evidence of the existence of the DSWs is based on the experimental determination of its complex propagation constant, whose imaginary part is significantly smaller compared to that found in the guided and leaky modes in the surrounding media. Metamaterial ; Numerical aperture ; Nanophotonics ; Light scattering ; Transformation optics ; Scattering ; Photonics ; Optics ; Aperture (computer memory) ; Photonic metamaterial ; Nanostructure ; Nanolithography ; Physics ; Optoelectronics ; Materials science ; Wavelength ; Nanotechnology ; Acoustics ; Fabrication Metamaterials and Metasurfaces Applications ; Plasmonic and Surface Plasmon Research ; Optical Wireless Communication Technologies
Authors: John P. Anton
Source: CUNY Academic Works (City University of New York) (article, 2018-01-01)
Field: Chemistry — Physical and Theoretical Chemistry

Aluminum-26: A Canonized Cosmochemical Conundrum This study focuses on the challenges associated with the historical development of the interpretative role of 26Al as both a thermodynamic contributor to planetesimal formation processes and an acutely precise chronometer of protoplanetary disk events. Conventional thought asserts that 26Mg concentrations can occur as isotopic excesses in meteorites and represent the daughter product of 26Al, a radioactive form of aluminum (t½ = ~0.73 ka). The greatest 26Mg concentrations generally occur in calcium aluminum inclusions (CAIs), meteoric constituents considered among the oldest known materials in the Solar System whose formation appear to predate the less refractory protoplanetary building blocks known as “chondrules.” The tendency for CAIs to exhibit higher 26Mg concentrations than chondrules is considered support for assigning a later formation age (e.g., 1-2 Ma younger) to the latter, a notion bolstered by some literature supporting this perspective based on Pb-age dating (e.g., Amelin et al., 2002; Bouvier and Wadhwa, 2010; Zinner E. and C. Göpel. 2002). Given that 26Al is the parent material of meteoric 26Mg excesses, then certain minimum criteria must be met before 26Al can be accepted as a fine-tuned chronometer or the proposed chief source of internal heat for planetesimals. First, 26Mg excesses must be genuine and solely a result of a specific decay pathway associated with 26Al decay rather than an artifact of extraneous factors, including analytical method biasing or data misinterpretation. Secondly, 26Al was uniformly distributed throughout the protoplanetary disk (at least within the orbits that terrestrial bodies reside). Last, the original 26Al concentration in the protoplanetary disk must be known before this isotope can be considered a chronometer. When 26Mg excesses are compared to the ratio of stable isotopic concentrations (27Al/24Mg), the resulting calculated value of the initial 26Al/27Al ratio consistently appears to be approximately 5x10-5. This special value is considered ‘canonical’ and referred to as such. It is also worth mentioning that if any of the aforementioned criteria are not satisfied, then the case for pointing to 26Al as the chief internal heat source for planetesimals or as a viable chronometer fails. The principal goal of this thesis is to test the validity of the results published by MacPherson et al. (1995). Their work is arguably one of the most comprehensive canonical model studies to date. This thesis also evaluated the strength of the canonical model via new perspectives and the results thereof are discussed herein and pose serious considerations regarding the nature and meaning of the ‘canonical’ value as well as the cogency of utilizing 26Al as a relative dating tool. Philosophy History and advancements in chemistry
Authors: Suhair A. Bani‐Atta
Source: JORDANIAN JOURNAL OF ENGINEERING AND CHEMICAL INDUSTRIES (JJECI) (article, 2018-12-01)
Field: Materials Science — Materials Chemistry

Different Polyoxometalate Structures Obtained from theNa11H[H(2-x)Bi2W20O70(HWO3)x]·46H2O(x=1.4). In the supramolecular chemistry world, Polyoxometalates (POMs) are considered as a new family of inorganic molecular containers, construct itself by self-assembly reaction from very small units, to form a cluster with unique structural and properties. three structures reported in this paper - differ in their unit cell parameters and also differ from the well-known - as the result of reaction of the Na11H[H(2- x)Bi2W20O70(HWO3)x]·46H2O (x=1.4) with Ca ion at different pH conditions. These structures are [Ca(H2O)7]2[Na(H2O)2]2[HBi2W20O70(HWO3)].14H2O(1), H2[NH4]10[HBi2W20O70(HWO3)] (2), and [NH4]6[Na(H2O)4]2[Ca(H2O)4]2[W12O42].2H2O (3). The last one is bismuth-free and it is formed through reassembly of the precursor. Full structural characterization was made by multiple testing techniques such as single-crystal X-ray diffraction, UV-visible spectroscopy, FT-IR, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The single-crystal X-ray diffraction results for the three compounds are as follows:(1), Triclinic, space group P-1, while (2) and (3) crystallize in monoclinic space groups C2/m and P21/n respectively. Polyoxometalate ; Triclinic crystal system ; Monoclinic crystal system ; Crystallography ; Supramolecular chemistry ; Thermogravimetric analysis ; Chemistry ; Bismuth ; Spectroscopy ; Crystal structure ; Scanning electron microscope ; Single crystal ; Powder diffraction ; Infrared spectroscopy ; Materials science ; Physics Polyoxometalates: Synthesis and Applications ; Metal-Organic Frameworks: Synthesis and Applications ; Advanced Nanomaterials in Catalysis
Authors: Pengfei Ji
Source: Knowledge@UChicago (University of Chicago) (article, 2018-01-01)
Field: Chemistry — Inorganic Chemistry

Transforming Hydroxides in Metal-Organic Framework Nodes for Catalytic Applications MOFs have provided a highly tunable platform to access site-isolated catalysts that do not undergo multimetallic decomposition. Such site-isolation effect has allowed the design and synthesis of a large variety of novel catalysts that do not have homogeneous or heterogeneous analogues. My research was focused on the hydroxide groups on the MOF nodes, which offer powerful means for introducing catalytic functionalities. Chapter 1 of this thesis discusses general design strategies for MOFs, with specific focus on Zr-based MOFs. This class of MOFs offer an ideal platform to create novel and stable catalysts on the inorganic nodes through different post-synthetic modifications. Chapter 2 through Chapter 6 of this thesis explore the use of inorganic MOF nodes with bridging hydroxides as binding sites for generating various single-site solid catalysts. For example, the Zr3-OH functionality in Zr6TPDC was metalated with MgMe2 or CoCl2 to afford highly active catalysts for carbonyl hydroboration or C-H bond borylation reactions. To increase the electron-donating ability and open space around the Zr3-OH group, three MOFs including Zr8MTBC, Zr12TPDC and Ti8BDC with new inorganic nodes were synthesized. These inorganic nodes were shown to provide superior supports for cobalt catalysts. Chapter 7 through Chapter 10 of this thesis examine the transformation of inorganic nodes with terminal hydroxides into competent catalysts for a variety of transformations. For example, Ce6-BTC has six terminal hydroxides per Ce6 node which can be activated by pinacol borane to afford terminal hydrides that are active for pyridine hydroboration, alkene hydroboration and alkene hydrophosphination. Other MOFs with terminal hydroxides were similarly activated to generate highly effective catalysts for olefin polymerization and pyridine hydroboration and hydrosilylation reactions. Catalysis ; Chemistry ; Environmental science ; Business ; Computer science ; Process engineering ; Engineering ; Organic chemistry Metal-Organic Frameworks: Synthesis and Applications
Authors: Natee Sirisit
Source: Hokkaido University Collection of Scholarly and Academic Papers (Hokkaido University) (article, 2018-12-25)
Field: Materials Science — Materials Chemistry

Advanced XAFS analysis for local structure of functional materials X-ray absorption fine structure ; Materials science ; Physics Machine Learning in Materials Science ; X-ray Diffraction in Crystallography ; X-ray Spectroscopy and Fluorescence Analysis
Authors: 良 飯田
Source: Hokkaido University Collection of Scholarly and Academic Papers (Hokkaido University) (article, 2018-03-22)
Field: Materials Science — Biomaterials

Control of Nanoparticle Self-Assembly in Water by Rational Surface Design Nanotechnology refers to a technology that controls substances from a few nanometers to less than100 nanometers Control (management) ; Computer science ; Artificial intelligence Diatoms and Algae Research ; Micro and Nano Robotics ; Electrostatics and Colloid Interactions
Authors: MH Maarten Bakker
Source: Data Archiving and Networked Services (DANS) (article, 2018-01-30)
Field: Materials Science — Biomaterials

Supramolecular drug delivery systems: molecular engineering of carrier affinity Drug delivery ; Supramolecular chemistry ; Molecular engineering ; Chemistry ; Drug ; Drug carrier ; Combinatorial chemistry ; Nanotechnology ; Stereochemistry ; Materials science ; Medicine ; Organic chemistry ; Pharmacology ; Molecule Nanoparticle-Based Drug Delivery ; Monoclonal and Polyclonal Antibodies Research ; RNA Interference and Gene Delivery
Authors: James A. Neal
Source: eScholarship (California Digital Library) (article, 2018-01-01)
Field: Materials Science — Polymers and Plastics

Advanced Polymeric Materials via Manipulation of Dynamic Molecular Interactions Tremendous synthetic advances in the fields of organic and polymer chemistry have created new opportunities to design advanced, new polymeric materials. Empowered with a suite of advanced synthetic tools, researchers have looked to nature for new inspiration in materials design. Nature has provided a near endless stream of ideas to draw upon for new advanced materials. The goal of this dissertation is to use lessons learned from nature to create cutting-edge, advanced polymeric materials that rely on dynamic molecular interactions. The thesis begins, in Chapter 1, with the background of each individual chapter, including both a guiding principle from nature, as well as, examples of selected previously published work in the field.In Chapter 2, I draw on lessons learned from the human bone to incorporate sacrificial hydrogen bonds into a covalently crosslinked self-healing material. This work addresses the long-standing challenge in the field of self-healing materials by combining robust mechanical and efficient self-healing properties. Specifically, the toughness of the material is increased 7-fold.In Chapter 3, I draw from the observation that nature displays remarkable ranges in mechanical properties from simple building blocks to create a widely tunable metallopolymer system. Specifically, the mechanical performance of the system is tuned from viscous oils to stiff plastics by careful selection of type and amount of added metal. This behavior is explained via ligand exchange mechanism, where associative and dissociative mechanisms are leveraged to achieve widely different properties.In Chapter 4, I imitate the mechanical gradients commonly observed in nature that protect biological materials from damage. Through a sophisticated understanding of metal-ligand crosslinks, I develop a novel approach to generating stiffness gradients in polymeric materials. The result is a mechanical gradient that spans over a 200-fold difference in stiffness.In Chapter 5, I attempt to duplicate the impressive moldability of silicate glass in covalently crosslinked polymer networks. Towards this goal, I have identified the silyl ether motif as a potential key to creating commercially-relevant vitrimer materials. If successful, these vitrimeric materials could replace thermosets in a variety of applications. Nanotechnology ; Computer science ; Mechanical engineering ; Materials science ; Engineering Polymer composites and self-healing
Authors: Khan Mohammad Ahsan Uddin
Source: Aaltodoc (Aalto University) (article, 2018-01-01)
Field: Materials Science — Biomaterials

Control of Silver Nano-particle Nucleation and Synthesis with Nanocelluloses: Applications in Paper-based Sensing and Anti-microbial Activity The synthesis of silver nanoparticles (AgNPs) has drawn significant research interest due to their unique and well-defined physical-chemical properties. Developing a feasible chemical method to synthesize silver nanoparticles using sustainable, renewable, and environmentally friendly materials is very important for environmental safely. In this work, a new route for the synthesis of silver nanoparticles (AgNPs) by using sustainable, renewable and environmentally friendly cellulose nanocrystals (CNCs) is described. Moreover, in this study the utilization of cellulose-AgNPs materials in sensing and antibacterial applications was investigated. The influence of the surface charge of cellulose nanocrystals on the rate of nucleation, growth, stabilization and size distribution of AgNPs was investigated. CNCs produced by sulfuric acid hydrolysis followed by partial desulfation and CNC produced by hydrochloric acid (HCl) hydrolysis followed by different levels of carboxylation by TEMPO-mediated oxidation were used to elucidate the effects of sulfate ester and of carboxyl groups on the silver nanoparticle synthesis process. The results shed light on the mechanistic aspects related to synthesis, control of nucleation, and stabilization of AgNP in a sustainable way, and highlight the potential of CNCs in metal nanoparticle synthesis. The fundamental knowledge of controlled nucleation of plasmonic silver nanoparticles by cellulose was applied to demonstrate a new plasmonic sensing mechanism for qualitative detection of proteins on paper. In contrast to conventional paper-based diagnostic devices that use the cellulosic component as a support structure, the proposed method takes advantage of cellulose as a nucleation controller during silver nanoparticle formation. Reduction of silver ions interacting competitively with the nucleation controlling cellulosic surface and the suppressing effect of protiens on reduction (via complexation) resulted in silver nanoparticles whose size–shape dependent plasmonic properties quantitatively reflected the concentration of protein on paper. In addition, aerogels prepared from aqueous dispersions of anionic and cationic cellulose nanofibrils (CNFs) were investigated as solid supports for enzymes and silver nanoparticles to elicit a sustained antibacterial effect. The antibacterial activity of CNF aerogels loaded with silver nanoparticles (AgNP) after in situ synthesis via UV reduction was tested against gram-negative and gram-positive bacteria. The results were compared with CNFs aerogels carrying antibacterial lysozyme. Nucleation ; Nanotechnology ; Nano- ; Biological system ; Particle (ecology) ; Silver Nano ; Materials science ; Biochemical engineering ; Chemistry ; Biology ; Engineering ; Ecology ; Composite material Advanced Cellulose Research Studies ; Biosensors and Analytical Detection
Authors: David Hermann Lamparelli | Antonio Ricca | Vincenzo Palma | Leone Oliva
Source: Molecules (article, 2018-05-25)
Field: Chemistry — Inorganic Chemistry

High Conversion of Styrene, Ethylene, and Hydrogen to Linear Monoalkylbenzenes 1-Alkylbenzenes as a precursor of surfactants, can be produced from ethylene, styrene, and hydrogen. These intermediates, lacking tertiary carbons, are environmentally more benign than commercial ones that bear the aromatic ring linked to an internal carbon of the aliphatic chain. The one-pot synthesis of highly linear 1-alkylbenzenes (LABs) through the homogeneous catalysis of olefin poly-insertion from cheap and largely available reagents can be carried out with a high turnover and selectivity. A purposely designed reactor that allows for the fine control of the three components feed, along with temperature, plays a key role in this achievement. A turnover of 194 g of LABs per mmol of catalyst per hour can be obtained with the simultaneous removal of polyethylene as a by-product. Alkylbenzenes ; Styrene ; Ethylene ; Olefin fiber ; Catalysis ; Reagent ; Selectivity ; Chemistry ; Organic chemistry ; Hydrogen ; Chemical engineering ; Polymer chemistry ; Copolymer ; Polymer Zeolite Catalysis and Synthesis ; Catalysis and Oxidation Reactions ; Asymmetric Hydrogenation and Catalysis