scholarly journals Evaluation of Mechanical Properties of Polysaccharide Films Prepared from Furcellaria Lumbricalis and Gigartina Skottsbergii Seaweeds by PF-QNM Technique

2021 ◽  
Author(s):  
Ivan Simkovic ◽  
Filip Gucmann ◽  
Raniero Mendichi ◽  
Alberto Giacometti Schieroni ◽  
Daniele Piovani ◽  
...  
Keyword(s):  
Complex Mixture ◽  
Xrd Analysis ◽  
Random Coil ◽  
Main Peak ◽  
Cellulose Content ◽  
Gigartina Skottsbergii ◽  
Seaweed Extracts ◽  
Furcellaria Lumbricalis ◽  
First Time ◽  
Compact Spheres

Abstract Films from Furcellaria lumbricalis (FL) and Gigartina skottsbergii (GS) seaweed extracts were prepared and their properties were investigated. According to NMR analysis of GS ultrasonic water (GSUW) extraction (1-3)-α-glycan 6-sulfate was isolated. The analogical treatment with carbonate-peroxide solution (GSUCP) resulted in a mixture of the same glycan and carrageenan hybrids µ-D6S and ν-D2S,6S observed for the first time in this study. The extraction of GS in boiling water under reflux (GSW) in comparison to FL (FLW), indicates that GSW consisted of the most complex mixture of α-, β-, κ-, ι-, θ-, ζ-carrageenans, (1-3)-α-glycan partially sulfated at C6, and µ-D6S and ν-D2S,6S hybrids. The analogical FLW extract contained α-, θ-, λ-, µ-, ν- and ζ-carrageenans and (1-3)-α-glycan partially sulphated at C6. SEC-MALS results indicate that molecular weight of chromatographic main peak (Mp) is decreasing: GSUCP (994 kg/mol) > GSUW (565 kg/mol) > FLW (498 kg/mol) > ι-carrageenan (264 kg/mol) > κ-carrageenan (174 kg/mol) > furcellaran (144 kg/mol) > GSW (78 kg/mol). Macromolecules conformation is varying from flexible random coil for κ-carrageenan to nearly compact spheres for ι-carrageenan. Furcellaran conformation is intermediate between κ-carrageenan and ι-carrageenan, specifically a little more compact than κ-carrageenan. XRD analysis confirmed no cellulose content in all prepared films. AFM and PF-QNM analysis showed relations between values of Rg and Mp and the values of surface roughness, reduced moduli, stiffness and adhesion.

Self-Irradiation of Monazite Ceramics: Contrasting Behavior of PuPO4 and (La,Pu)PO4 Doped with Pu-238

2004 ◽  
Vol 824 ◽  
Author(s):  
Boris E. Burakov ◽  
Maria A. Yagovkina ◽  
Vladimir M. Garbuzov ◽  
Alexander A. Kitsay ◽  
Vladimir A. Zirlin
Keyword(s):  
Radiation Damage ◽  
Crack Formation ◽  
Alpha Decay ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Deep Blue ◽  
Long Term Storage ◽  
First Time ◽  
Term Storage

AbstractTo investigate the behavior of monazite during accelerated radiation damage, which simulates effects of long term storage, 238Pu-doped polycrystalline samples of (La,Pu)PO4 and PuPO4 were synthesized for the first time ever and studied using powder X-ray diffraction (XRD) analysis and optical microscopy. The starting precursor materials were obtained by precipitation of La and (or) Pu from their aqueous nitrate solutions followed by calcination in air at 700°C for 1 hour, cold pressing, and sintering in air at 1200-1250°C for 2 hours. The 238Pu contents in ceramic samples measured using gamma spectrometry were (in wt.% el.): 8.1 for (La,Pu)PO4 and 7.2 for PuPO4. The (La,Pu)PO4 monazite remained crystalline at ambient temperature up to a cumulative dose of 1.19 × 1025 alpha decays/m3. In contrast, the PuPO4 monazite became nearly completely amorphous at a relatively low dose of 4.2 × 1024 alpha decays/m3. Swelling and crack formation due to the alpha decay damage was observed in the PuPO4 ceramic. Also, under self-irradiation this sample completely changed color from initial deep blue to black. The (La,Pu)PO4 monazite was characterized by a similar change in color from initial light blue to gray, however, no swelling or crack formation have so far been observed. The results of this study allow us to conclude that the radiation damage behavior of monazite strictly depends on the chemical composition. The justification of monazite-based ceramics as actinide waste forms requires additional investigation.

scholarly journals Long term Arecibo monitoring of the water megamaser in MG J0414+0534

2012 ◽  
Vol 8 (S287) ◽  
pp. 340-344
Author(s):  
Paola Castangia ◽  
C. M. Violette Impellizzeri ◽  
John P. McKean ◽  
Christian Henkel ◽  
Andreas Brunthaler ◽  
...  
Keyword(s):  
High Redshift ◽  
Main Peak ◽  
Powerful Radio ◽  
Upper Limit ◽  
Maser Line ◽  
Line Widths ◽  
Velocity Drift ◽  
First Time ◽  
Water Maser

AbstractWe monitored the 22 GHz maser line in the lensed quasar MG J0414+0534 at z = 2.64 with the 300-m Arecibo telescope for almost two years to detect possible additional maser components and to measure a potential velocity drift of the lines. The main maser line profile is complex and can be resolved into a number of broad features with line widths of 30-160 km s−1. A new maser component was tentatively detected in October 2008 at a velocity of +470 km s−1. After correcting for the estimated lens magnification, we find that the H2O isotropic luminosity of the maser in MG J0414+0534 is ~26,000 solar luminosities, making this source the most luminous ever discovered. Both the main line peak and continuum flux densities are surprisingly stable throughout the period of the observations. An upper limit on the velocity drift of the main peak of the line has been estimated from our observations and is of the order of 2 km s−1 per year. We discuss the results of the monitoring in terms of the possible nature of the maser emission, associated with an accretion disk or a radio jet. This is the first time that such a study is performed in a water maser source at high redshift, potentially allowing us to study the parsec-scale environment around a powerful radio source at cosmological distances.

scholarly journals Photoabsorption effect in the thin films of the CdPbS solid solutions

2020 ◽  
Vol 62 (6) ◽  
pp. 55-64
Author(s):  
Vyacheslav F. Markov ◽  
◽  
Karina V. Grashchenkova ◽  
Larisa N. Maskaeva ◽  
Yury G. Shashmurin ◽  
...  
Keyword(s):  
Nitrogen Dioxide ◽  
Solid Solutions ◽  
Deposition Time ◽  
Equilibrium Phase ◽  
Reaction System ◽  
Xrd Analysis ◽  
Cadmium Content ◽  
Crystallinity Degree ◽  
First Time ◽  
Crystallite Diameter

In this work, we have attempted to detect the photoadsorption effect using various photoactivation sources of semiconductor layers of CdxPb1–xS solid solutions that are sensitive to the presence of nitrogen dioxide in air. For this purpose, CdxPb1–xS films (up to 600 nm thick) were synthesized from the citrate – ammonia reaction system by the chemical bath deposition (CBD) on glass and sitall substrates. Using XRD analysis, we determined the structure and composition of CdxPb1–xS solid solutions. It was found that all films crystallize in the cubic structure B1 of lead sulfide. Taking into account the content of the substituting component in the samples and comparing it with the equilibrium phase diagrams of the PbS-CdS system, we concluded that the obtained solid solutions are strongly supersaturated in nature. The cadmium content in the PbS lattice increases in films deposited on sitall and glass from 3.9 to 5.9 and from 4.3 to 5.4 at.% with an increase in the deposition time from 60 to 120 minutes, respectively. It must be noted that their crystallinity degree increases with increasing deposition time. The size of the particles forming the layers was determined by SEM microscopy. The predominant crystallite diameter is 250-300 nm. The sensory properties of films of CdxPb1–xS solid solutions with respect to the presence of nitrogen dioxide with a concentration of 100 mg/m3 in air were studied using preliminary photoactivation by various sources with a radiation wavelength from 420 to 1000 nm. For the first time, a positive photoadsorption effect was revealed for CBD produced films of CdxPb1–xS solid solutions. The preliminary photoactivation of the films with a blue lamp (760–1000 nm) for 9-13 minutes allows the film to increase the response to NO2 more than doubled. A high relaxation rate of CdxPb1–xS -based sensor elements after contact with nitrogen dioxide was shown to be 4–10 minutes, which allows to reuse it.

scholarly journals Optical polarised phase function of the HR 4796A dust ring

2019 ◽  
Vol 626 ◽  
pp. A54 ◽  
Author(s):  
J. Milli ◽  
N. Engler ◽  
H. M. Schmid ◽  
J. Olofsson ◽  
F. Ménard ◽  
...  
Keyword(s):  
Phase Function ◽  
Scattered Light ◽  
Dust Particles ◽  
Cometary Dust ◽  
Very Large Telescope ◽  
Wide Range ◽  
Alternative Scenarios ◽  
First Time ◽  
Dust Ring ◽  
Compact Spheres

Context. The scattering properties of the dust originating from debris discs are still poorly known. The analysis of scattered light is however a powerful remote-sensing tool to understand the physical properties of dust particles orbiting other stars. Scattered light is indeed widely used to characterise the properties of cometary dust in the solar system. Aims. We aim to measure the morphology and scattering properties of the dust from the debris ring around HR 4796 A in polarised optical light. Methods. We obtained high-contrast polarimetric images of HR 4796 A in the wavelength range 600–900 nm with the SPHERE/ZIMPOL instrument on the Very Large Telescope. Results. We measured for the first time the polarised phase function of the dust in a debris system over a wide range of scattering angles in the optical. We confirm that it is incompatible with dust particles being compact spheres under the assumption of the Mie theory, and propose alternative scenarios compatible with the observations, such as particles with irregular surface roughness or aggregate particles.

Effect of carbon sources on physicochemical properties of bacterial cellulose produced from Gluconacetobacter xylinus MTCC 7795

e-Polymers ◽  
2016 ◽  
Vol 16 (4) ◽  
pp. 331-336
Author(s):  
Rushali Singh ◽  
Ashwani Mathur ◽  
Navendu Goswami ◽  
Garima Mathur
Keyword(s):  
Physicochemical Properties ◽  
Bacterial Cellulose ◽  
Specific Growth ◽  
Carbon Sources ◽  
Xrd Analysis ◽  
Culture Conditions ◽  
Shake Flask Culture ◽  
Gluconacetobacter Xylinus ◽  
X Ray ◽  
First Time

AbstractIn this study, the effect of modified Hestrin Schramm (HS) medium supplemented with different carbon sources viz., glucose, fructose, galactose and lactic acid on the yield and physicochemical properties of bacterial cellulose (BC) produced from Gluconacetobacter xylinus strain MTCC 7795 in shake flask culture conditions was investigated. Growth studies indicated that all carbon sources supported the growth of bacteria, though specific growth rate and doubling time differs. Fructose gave the highest cellulose yield of 7.72 mg/ml after 130 h of fermentation, while yield in glucose and galactose supplemented medium were 4.49 mg/ml and 3.38 mg/ml, respectively. X-ray powder diffraction (XRD) analysis revealed that all BC samples were amorphous in comparison to commercial cellulose. Fourier transform infrared (FTIR) spectroscopic investigations of bacterial cellulose (BC) samples affirm the purity of the cellulose produced. No significant variations in physicochemical properties of cellulose samples produced with different carbon sources were observed. This study for the first time has investigated the effect of carbon sources on physicochemical properties of bacterial cellulose produced by G. xylinus MTCC 7795 and provides a strategy for economical production of BC with anticipated application in therapeutics and tissue engineering.

The Effect of Substrate on TiO2 Thin Films Deposited by Atomic Layer Deposition (ALD)

2015 ◽  
Vol 1087 ◽  
pp. 147-151 ◽  
Author(s):  
Rosniza Hussin ◽  
Kwang Leong Choy ◽  
Xiang Hui Hou
Keyword(s):  
Thin Films ◽  
Atomic Layer ◽  
Xrd Analysis ◽  
Titanium Isopropoxide ◽  
Steel Plates ◽  
Main Peak ◽  
Polycrystalline Thin Films ◽  
Crystal Substrate ◽  
The Difference ◽  
Xrd Patterns

ALD is a precision growth technique that can deposit either amorphous or polycrystalline thin films on a variety of substrates. The difference in substrate can cause a variation in the ALD process, even it is carried out using the same reactants and deposition conditions [1]. TiO2thin films were grown using TTIP (Titanium isopropoxide) ALD on silicon wafers, glass slides, and stainless steel plates in order to study the effect of substrates on the growth of TiO2with 3,000 deposition cycles, at 300°C.The thin films were analyzed using Xray Diffraction (XRD), Raman Spectroscopy, Atomic Force Microscope (AFM) and Spectroscopic Ellipsometer. From XRD analysis were indicates the main peak for anatase (101) (2θ= 25.3) was observed from the XRD patterns for TiO2on all substrates. The results show that crystalline TiO2thin films can easily grow on a crystal substrate rather than on an amorphous substrate.

Development of advanced, non-toxic, synthetic radiation shielding aggregate

2018 ◽  
Vol 106 (1) ◽  
pp. 59-68 ◽  
Author(s):  
Manish Mudgal ◽  
Ramesh Kumar Chouhan ◽  
Sarika Verma ◽  
Sudhir Sitaram Amritphale ◽  
Satyabrata Das ◽  
...  
Keyword(s):  
Red Mud ◽  
Nuclear Power ◽  
Power Plants ◽  
Xrd Analysis ◽  
Radiation Shielding ◽  
Industry Waste ◽  
Hematite Ore ◽  
First Time ◽  
Different Sources ◽  
Aggregate Impact Value

AbstractFor the first time in the world, the capability of red mud waste has been explored for the development of advanced synthetic radiation shielding aggregate. Red mud, an aluminium industry waste consists of multi component, multi elemental characteristics. In this study, red mud from two different sources have been utilized. Chemical formulation and mineralogical designing of the red mud has been done by ceramic processing using appropriate reducing agent and additives. The chemical analysis, SEM microphotographs and XRD analysis confirms the presence of multi-component, multi shielding and multi-layered phases in both the different developed advance synthetic radiation shielding aggregate. The mechanical properties, namely aggregate impact value, aggregate crushing value and aggregate abrasion value have also been evaluated and was compared with hematite ore aggregate and found to be an excellent material useful for making advanced radiation shielding concrete for the construction of nuclear power plants and other radiation installations.

scholarly journals Properties of RF Magnetron-Sputtered Copper Gallium Oxide (CuGa2O4) Thin Films

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 921
Author(s):  
Ashwin Kumar Saikumar ◽  
Sreeram Sundaresh ◽  
Shraddha Dhanraj Nehate ◽  
Kalpathy B. Sundaram
Keyword(s):  
Thin Films ◽  
Annealing Temperature ◽  
Wavelength Region ◽  
Rf Magnetron Sputtering ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Morphological Studies ◽  
Increasing Trend ◽  
First Time ◽  
Post Deposition

Thin films of CuGa2O4 were deposited using an RF magnetron-sputtering technique for the first time. The sputtered CuGa2O4 thin films were post-deposition annealed at temperatures varying from 100 to 900 °C in a constant O2 ambience for 1.5 h. Structural and morphological studies were performed on the films using X-ray diffraction analysis (XRD) and a Field Emission Scanning Electron Microscope (FESEM). The presence of CuGa2O4 phases along with the CuO phases was confirmed from the XRD analysis. The minimum critical temperature required to promote the crystal growth in the films was identified to be 500 °C using XRD analysis. The FESEM images showed an increase in the grain size with an increase in the annealing temperature. The resistivity values of the films were calculated to range between 6.47 × 103 and 2.5 × 108 Ωcm. Optical studies were performed on all of the films using a UV-Vis spectrophotometer. The optical transmission in the 200–800 nm wavelength region was noted to decrease with an increase in the annealing temperature. The optical bandgap value was recorded to range between 3.59 and 4.5 eV and showed an increasing trend with an increase in the annealing temperature.

scholarly journals The method of cleaning and modification of the material for bone xenografts in bi-phase media containing high pressure CO2

2019 ◽  
Vol 485 (5) ◽  
pp. 588-593
Author(s):  
M. V. Bulat ◽  
M. A. Pigaleva ◽  
I. V. Novikov ◽  
E. E. Levin ◽  
M. O. Gallyamov
Keyword(s):  
High Pressure ◽  
Bone Tissue ◽  
Xrd Analysis ◽  
Mineral Phase ◽  
Dispersed Particles ◽  
Animal Bone ◽  
High Pressure Co2 ◽  
Bone Fragments ◽  
First Time ◽  
Highly Dispersed Particles

In the present work, a promising method was proposed for purification of fragments of animal bone tissue from high-molecular weight compounds in bi-phase media containing high-pressure CO2 for the first time, namely, in solutions of carbonic and peroxycarbonic acids. The effectiveness of this purification was confirmed by SEM and IR spectroscopy. It turned out that during the exposure of bone fragments in solutions of carbonic and peroxycarbonic acids under high pressure of CO2, the components of the mineral phase of bone tissue are also extracted, which allows to obtain highly dispersed particles of hydroxyapatite during the deposition of the extract. The structure and composition of the extracts were investigated by XRD analysis and SEM.

scholarly journals Bioprocessing of Waste Sago Pulp Fiber Based on Chloride Solution for Cellulose Isolation

2021 ◽  
Vol 12 (1) ◽  
pp. 441-449
Keyword(s):  
Chloride Solution ◽  
Crystal Size ◽  
Xrd Analysis ◽  
Solution Concentration ◽  
Sem Analysis ◽  
Pulp Fiber ◽  
Ir Absorption ◽  
Powder Size ◽  
Cellulose Content ◽  
Cellulose Surface

The utilization of chloride solution in the bioprocessing of sago pulp fiber waste (SPFW) aims to obtain high purity cellulose before its use in making bioethanol. Before the bioprocessing, SPFW with a powder size of 149 μm was immersed in 15% (v/v) NH4OH and 5% (v/v) H2O2 solution. Bioprocessing parameters reported in this study included bioprocessing time, chloride solution concentration, and bioprocessing temperature. Based on the optimization results, the SPFW bioprocessing for 5 hours using 4% hydrochloric acid and a temperature of 95oC was the optimum condition with the acquisition of cellulose content of 67%. SPFW cellulose was confirmed by the presence of specific IR absorption peaks at wave numbers 1429.4 cm-1, 1322.4 cm-1, 1157.3 cm-1, 1110 cm-1, and 897 cm-1. Scanning Electron Microscopy (SEM) analysis shows that bioprocessing using chloride solutions produces a porous, rough, and fibrous cellulose surface. Also, the fiber length is irregular with the irregular location. Based on XRD analysis, SPFW bioprocessing produced single-phase cellulose with a crystal size of 15 nm. Physically, the bioprocessing causes the discoloration of the sago pulp fiber to turn dark brown.

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