scholarly journals Synthesis and Characterization of Crystalline NaY-Zeolite from Belitung Kaolin as Catalyst for n-Hexadecane Cracking

Crystals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 404 ◽  
Author(s):  
Yuni K. Krisnandi ◽  
Indah R. Saragi ◽  
Riwandi Sihombing ◽  
Rizki Ekananda ◽  
Indah P. Sari ◽  
...  
Keyword(s):  
High Performance ◽  
Colloidal Silica ◽  
Nay Zeolite ◽  
Percentage Yield ◽  
Structure Similarity ◽  
The One ◽  
Silica Synthesis ◽  
Nay Zeolites ◽  
Cracking Catalysts

Crystalline sodium Y (NaY) zeolite has been synthesized using alternative natural source of aluminate and silicate, extracted from natural Belitung kaolin. Prior to use, the natural kaolin was pretreated to obtain fragmented metakaolin and extracted silica. Synthesis was conducted with the addition of NaY gel (two types of NaY seeds were used, prepared from colloidal sillica or sodium silica water) using hydrothermal method for 21 h at 100 °C. The characterization on the as-synthesized zeolites confirmed that the one prepared using colloidal silica-seed has closer structure similarity to NaY zeolite that was synthesized using pro analysis silicate and aluminate sources. Thus, the rest of the synthesis of NaY was carried out using colloidal silica-NaY seed. The NaY zeolites then were converted to HY, through ammonium-exchange followed by calcination, to be tested as cracking catalysts using n-hexadecane as a probe molecule. It shows that HY from metakaolin and extracted silica gives high performance, i.e., n-hexadecane conversion of 58%–64%, also C5-C12 percentage yield and selectivity of 56%–62% and 98%. This work has shown the potential to utilize kaolin as alternative silicate aluminate sources for crystalline zeolite synthesis and to obtain inexpensive and environmentally friendly catalyst materials.

scholarly journals Preparation and Characterization of Stealth Archaeosomes Based on a Synthetic PEGylated Archaeal Tetraether Lipid

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Julie Barbeau ◽  
Sandrine Cammas-Marion ◽  
Pierrick Auvray ◽  
Thierry Benvegnu
Keyword(s):  
High Performance ◽  
Drug Carriers ◽  
Physicochemical Characteristics ◽  
Release Studies ◽  
Poly Ethylene ◽  
Membrane Spanning ◽  
The Stability ◽  
The One ◽  
Egg Pc

The present studies were focused on the formation and characterization of sterically stabilized archaeosomes made from a synthetic PEGylated archaeal lipid. In a first step, a synthetic archaeal tetraether bipolar lipid was functionalized with a poly(ethylene glycol), PEG, and (PEG45-Tetraether) with the aim of coating the archaeosome surface with a sterically stabilizing hydrophilic polymer. In a second step, Egg-PC/PEG45-Tetraether (90/10 wt%) archaeosomes were prepared, and their physicochemical characteristics were determined by dynamic light scattering (size, polydispersity), cryo-TEM (morphology), and by high-performance thin layer chromatography (lipid composition), in comparison with standard Egg-PC/PEG45-DSPE formulations. Further, a fluorescent dye, the carboxyfluorescein, was encapsulated into the prepared archaeosomes in order to evaluate the potential of such nanostructures as drug carriers. Release studies have shown that the stability of Egg-PC/PEG45-Tetraether-based archaeosomes is significantly higher at 37∘C than the one of Egg-PC/PEG45-DSPE-based liposomes, as evidenced by the slower release of the dye encapsulated into PEGylated archaeosomes. This enhanced stability could be related to the membrane spanning properties of the archaeal bipolar lipid as already described with natural or synthetic tetraether lipids.

Preparation and Characterization of NH2-Terminal Fibrinogen Bβ Fragments from N-DSK of Human Fibrinogen

1984 ◽  
Vol 51 (01) ◽  
pp. 016-021 ◽  
Author(s):  
S Birken ◽  
G Agosto ◽  
B Lahiri ◽  
R Canfield
Keyword(s):  
High Performance ◽  
Gel Filtration ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Reverse Phase ◽  
Human Fibrinogen ◽  
Human Volunteers ◽  
Cnbr Cleavage ◽  
Two Peaks

SummaryIn order to investigate the early release of NH2-terminal plasmic fragments from the Bβ chain of fibrinogen, substantial quantities of Bβ 1-42 and Bβ 1-21 are required as immunogens, as radioimmunoassay standards and for infusion into human volunteers to determine the half-lives of these peptides. Towards this end methods that employ selective proteolytic cleavage of these fragments from fibrinogen have been developed. Both the N-DSK fragment, produced by CNBr cleavage of fibrinogen, and Bβ 1-118 were employed as substrates for plasmin with the finding of higher yields from N-DSK. Bβ 1-42 and Bβ 1-21 were purified by gel filtration and ion-exchange chromatography on SP-Sephadex using volatile buffers. When the purified preparation of Bβ 1-42 was chromatographed on reverse-phase high performance liquid chromatography, two peaks of identical amino acid composition were separated, presumably due either to pyroglutamate or to amide differences.

Preparation and Characterization of the High Molecular Weight [3H]Hyaluronic Acid

1992 ◽  
Vol 57 (10) ◽  
pp. 2151-2156 ◽  
Author(s):  
Peter Chabreček ◽  
Ladislav Šoltés ◽  
Hynek Hradec ◽  
Jiří Filip ◽  
Eduard Orviský
Keyword(s):  
Molecular Weight ◽  
Hyaluronic Acid ◽  
High Molecular Weight ◽  
Methyl Bromide ◽  
High Performance ◽  
Hydrogen Atoms ◽  
Isolation And Characterization ◽  
Labelling Procedure ◽  
Enzymatic Depolymerization

Two methods for the preparation of high molecular weight [3H]hyaluronic acid were investigated. In the first one, hydrogen atoms in the molecule were replaced by tritium. This isotopic substitution was performed in aqueous solution using Pd/CaCO3 as the catalyst. In the second method, the high molecular weight hyaluronic acid was alkylated with [3H]methyl bromide in liquid ammonia at a temperature of -33.5 °C. High-performance gel permeation chromatographic separation method was used for the isolation and characterization of the high molecular weight [3H]hyaluronic acid. Molecular weight parameters for the labelled biopolymers were Mw = 128 kDa, Mw/Mn = 1.88 (first method) and Mw = 268 kDa, Mw/Mn = 1.55 (second method). The high molecular weight [3H]hyaluronic acid having Mw = 268 kDa was degraded further by specific hyaluronidase. Products of the enzymatic depolymerization were observed to be identical for both, labelled and cold biopolymer. This finding indicates that the described labelling procedure using [3H]methyl bromide does not induce any major structural rearrangements in the molecule.

scholarly journals Synthesis and Polymerization Kinetics of Rigid Tricyanate Ester

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1686
Author(s):  
Andrey Galukhin ◽  
Roman Nosov ◽  
Ilya Nikolaev ◽  
Elena Melnikova ◽  
Daut Islamov ◽  
...  
Keyword(s):  
Kinetic Analysis ◽  
Single Step ◽  
Polymerization Kinetics ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
Diffusion Controlled ◽  
Polymerization Product ◽  
The One ◽  
Kinetics Of

A new rigid tricyanate ester consisting of seven conjugated aromatic units is synthesized, and its structure is confirmed by X-ray analysis. This ester undergoes thermally stimulated polymerization in a liquid state. Conventional and temperature-modulated differential scanning calorimetry techniques are employed to study the polymerization kinetics. A transition of polymerization from a kinetic- to a diffusion-controlled regime is detected. Kinetic analysis is performed by combining isoconversional and model-based computations. It demonstrates that polymerization in the kinetically controlled regime of the present monomer can be described as a quasi-single-step, auto-catalytic, process. The diffusion contribution is parameterized by the Fournier model. Kinetic analysis is complemented by characterization of thermal properties of the corresponding polymerization product by means of thermogravimetric and thermomechanical analyses. Overall, the obtained experimental results are consistent with our hypothesis about the relation between the rigidity and functionality of the cyanate ester monomer, on the one hand, and its reactivity and glass transition temperature of the corresponding polymer, on the other hand.

scholarly journals Comparative Study of the Field Performances of Pressure-Grouted Micropiles Using Gravity and Packers

2021 ◽  
Vol 11 (15) ◽  
pp. 6736
Author(s):  
Ong Heo ◽  
Yeowon Yoon ◽  
Jinung Do
Keyword(s):  
Urban Areas ◽  
High Performance ◽  
Driving Forces ◽  
Field Performance ◽  
Underground Space ◽  
Creep Tests ◽  
Deep Foundation ◽  
Installation Depth ◽  
Pressure Grouting ◽  
The One

When underground space requires excavation in areas below the water table, the foundation system suffers from buoyancy, which leads to the uplifting of the superstructure. A deep foundation system can be used; however, in cases where a hard layer is encountered, high driving forces and corresponding noises cause civil complaints in urban areas. Micropiles can be an effective alternative option, due to their high performance despite a short installation depth. Pressurized grouting is used with a packer to induce higher interfacial properties between micropile and soil. In this study, the field performance of micropiles installed using gravitational grouting or pressure-grouted using either a geotextile packer or rubber packer was comparatively evaluated by tension and creep tests. Micropiles were installed using pressure grouting in weak and fractured zones. As results, the pressure-grouted micropiles showed more stable and stronger behaviors than ones installed using the gravitational grouting. Moreover, the pressure-grouted micropile installed using the rubber packer showed better performance than the one using the geotextile packer.

scholarly journals AFX Zeolite for Use as a Support of NH3-SCR Catalyst Mining through AICE Joint Research Project of Industries–Academia–Academia

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 163
Author(s):  
Masaru Ogura ◽  
Yumiko Shimada ◽  
Takeshi Ohnishi ◽  
Naoto Nakazawa ◽  
Yoshihiro Kubota ◽  
...  
Keyword(s):  
High Performance ◽  
Ionic Species ◽  
Research Project ◽  
Joint Research ◽  
Structure Directing Agent ◽  
Scr Catalyst ◽  
Organic Structure ◽  
Nh3 Scr ◽  
Joint Research Project ◽  
The One

This paper introduces a joint industries–academia–academia research project started by researchers in several automobile companies and universities working on a single theme. Our first target was to find a zeolite for NH3-SCR, that is, zeolite mining. Zeolite AFX, having the same topology of SSZ-16, was found to be the one of the zeolites. SSZ-16 can be synthesized by using an organic structure-directing agent such as 1,1′-tetramethylenebis(1-azonia-4-azabicyclo[2.2.2]octane; Dab-4, resulting in the formation of Al-rich SSZ-16 with Si/Al below five. We found that AFX crystallized by use of N,N,N′,N′-tetraethylbicyclo[2.2.2]oct-7-ene-2,3:5,6-dipyrrolidinium ion, called TEBOP in this study, had the same analog as SSZ-16 having Si/Al around six and a smaller particle size than SSZ-16. The AFX demonstrated a high performance for NH3-SCR as the zeolitic support to load a large number of divalent Cu ionic species with high hydrothermal stability.

scholarly journals Development and characterization of Nb3Sn/Al2O3 superconducting multilayers for particle accelerators

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chris Sundahl ◽  
Junki Makita ◽  
Paul B. Welander ◽  
Yi-Feng Su ◽  
Fumitake Kametani ◽  
...  
Keyword(s):  
High Performance ◽  
High Energy ◽  
Particle Accelerators ◽  
Quality Factors ◽  
Critical Fields ◽  
Linear Accelerators ◽  
Cross Sectional ◽  
Low Field ◽  
Superconducting Radio Frequency

AbstractSuperconducting radio-frequency (SRF) resonator cavities provide extremely high quality factors > 1010 at 1–2 GHz and 2 K in large linear accelerators of high-energy particles. The maximum accelerating field of SRF cavities is limited by penetration of vortices into the superconductor. Present state-of-the-art Nb cavities can withstand up to 50 MV/m accelerating gradients and magnetic fields of 200–240 mT which destroy the low-dissipative Meissner state. Achieving higher accelerating gradients requires superconductors with higher thermodynamic critical fields, of which Nb3Sn has emerged as a leading material for the next generation accelerators. To overcome the problem of low vortex penetration field in Nb3Sn, it has been proposed to coat Nb cavities with thin film Nb3Sn multilayers with dielectric interlayers. Here, we report the growth and multi-technique characterization of stoichiometric Nb3Sn/Al2O3 multilayers with good superconducting and RF properties. We developed an adsorption-controlled growth process by co-sputtering Nb and Sn at high temperatures with a high overpressure of Sn. The cross-sectional scanning electron transmission microscope images show no interdiffusion between Al2O3 and Nb3Sn. Low-field RF measurements suggest that our multilayers have quality factor comparable with cavity-grade Nb at 4.2 K. These results provide a materials platform for the development and optimization of high-performance SIS multilayers which could overcome the intrinsic limits of the Nb cavity technology.

scholarly journals Constructing Large-Scale Genetic Maps Using an Evolutionary Strategy Algorithm

Genetics ◽  
2003 ◽  
Vol 165 (4) ◽  
pp. 2269-2282
Author(s):  
D Mester ◽  
Y Ronin ◽  
D Minkov ◽  
E Nevo ◽  
A Korol
Keyword(s):  
Discrete Optimization ◽  
High Performance ◽  
Large Scale ◽  
Simulated Data ◽  
Real Data ◽  
Genetic Maps ◽  
Chromosome 1 ◽  
Evolutionary Strategy ◽  
Group A ◽  
The One

Abstract This article is devoted to the problem of ordering in linkage groups with many dozens or even hundreds of markers. The ordering problem belongs to the field of discrete optimization on a set of all possible orders, amounting to n!/2 for n loci; hence it is considered an NP-hard problem. Several authors attempted to employ the methods developed in the well-known traveling salesman problem (TSP) for multilocus ordering, using the assumption that for a set of linked loci the true order will be the one that minimizes the total length of the linkage group. A novel, fast, and reliable algorithm developed for the TSP and based on evolution-strategy discrete optimization was applied in this study for multilocus ordering on the basis of pairwise recombination frequencies. The quality of derived maps under various complications (dominant vs. codominant markers, marker misclassification, negative and positive interference, and missing data) was analyzed using simulated data with ∼50-400 markers. High performance of the employed algorithm allows systematic treatment of the problem of verification of the obtained multilocus orders on the basis of computing-intensive bootstrap and/or jackknife approaches for detecting and removing questionable marker scores, thereby stabilizing the resulting maps. Parallel calculation technology can easily be adopted for further acceleration of the proposed algorithm. Real data analysis (on maize chromosome 1 with 230 markers) is provided to illustrate the proposed methodology.

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