Highly Densified MgB2 Bulks by Reactive Mg Liquid Infiltration

2006 ◽  
Vol 47 ◽  
pp. 7-16 ◽  
Author(s):  
Giovanni Giunchi ◽  
Giovanni Ripamonti ◽  
Elena Perini ◽  
Stefano Ginocchio ◽  
Enrico Bassani ◽  
...  
Keyword(s):  
Polycrystalline Material ◽  
Bulk Material ◽  
Analytical Description ◽  
Liquid Infiltration ◽  
In Situ Method ◽  
New Process ◽  
Conventional Sintering ◽  
Reactive Liquid ◽  
Mgb2 Superconductors

The issues in the conventional sintering of the MgB2 superconductors have conducted to the discovery of a new way to densify this material. The new process is an “in situ” method that relies on the reactive liquid infiltration (RLI) of liquid Magnesium into Boron powders packed preform. The RLI process allows to obtain highly dense manufacts without the use of hot pressing apparatus and can be applied to the manufacture of large superconducting pieces. One of the peculiarities of the MgB2 superconductivity, that withstand up to 39 K, is represented by the relative insensitiveness of the supercurrent percolation to the orientation of the grain boundaries. This property allows to use polycrystalline material without loosing superconducting performance, granted that a good connectivity between the crystalline grains must be realized, as the RLI process allows to do. The microstructure of the bulk material obtained by RLI shows a variety of morphologies, according to the kind of the used Boron powders and to the process variables. A detailed analysis of the microstructure of the MgB2 obtained by RLI will be presented, as well as its analytical description and the correlation with the superconducting characteristics.

scholarly journals Application of Furcellaran Nanocomposite Film as Packaging of Cheese

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1428
Author(s):  
Agnieszka Pluta-Kubica ◽  
Ewelina Jamróz ◽  
Gohar Khachatryan ◽  
Adam Florkiewicz ◽  
Pavel Kopel
Keyword(s):  
Silver Nanoparticles ◽  
Nanocomposite Film ◽  
Microbiological Quality ◽  
Inhibitory Effect ◽  
Quality Properties ◽  
In Situ Method ◽  
And Migration ◽  
Total Bacteria

There is a serious need to develop and test new biodegradable packaging which could at least partially replace petroleum-based materials. Therefore, the objective of this work was to examine the influence of the recently developed furcellaran nanocomposite film with silver nanoparticles (obtained by an in situ method) on the quality properties of two cheese varieties: a rennet-curd (gouda) and an acid-curd (quark) cheese. The water content, physicochemical properties, microbiological and organoleptic quality of cheese, and migration of silver nanoparticles were examined. Both the number of Lactococcus and total bacteria count did not differ during storage of gouda regardless of the packaging applied. The number of Lactococcus decreased in analogous quark samples. The use of the film slowed down and inhibited the growth of yeast in gouda and quark, respectively. An inhibitory effect of this film on mold count was also observed; however, only regarding gouda. The level of silver migration was found to be lower in quark than in gouda. The film improved the microbiological quality of cheeses during storage. Consequently, it is worth continuing research for the improvement of this film in order to enable its use in everyday life.

Photocatalytic degradation of tetracycline under visible light using TiO2@sulfur doped carbon nitride nanocomposite synthesized via in-situ method

2021 ◽  
Vol 9 (4) ◽  
pp. 105560
Author(s):  
Krishnan Divakaran ◽  
Amanulla Baishnisha ◽  
Vellaichamy Balakumar ◽  
Krishnan Nattamai Perumal ◽  
Chandran Meenakshi ◽  
...  
Keyword(s):  
Visible Light ◽  
Photocatalytic Degradation ◽  
Carbon Nitride ◽  
In Situ Method

In Situ Diagnostics of Vuv Laser Cvd of Semiconductor Interfaces by Ftir Spectroscopy and Spectroscopic Ellipsometry

1995 ◽  
Vol 397 ◽  
Author(s):  
M. Barth ◽  
J. Knobloch ◽  
P. Hess
Keyword(s):  
Film Thickness ◽  
Bulk Material ◽  
Substrate Surface ◽  
Cluster Formation ◽  
Interface Layer ◽  
Native Oxide ◽  
Initial Growth ◽  
Difference Spectra ◽  
Si Substrates

ABSTRACTThe growth of high quality amorphous hydrogenated semiconductor films was explored with different in situ spectroscopic methods. Nucleation of ArF laser-induced CVD of a-Ge:H on different substrates was investigated by real time ellipsometry, whereas the F2 laser (157nm) deposition of a-Si:H was monitored by FTIR transmission spectroscopy. The ellipsometric studies reveal a significant influence of the substrate surface on the nucleation stage, which in fact determines the electronic and mechanical properties of the bulk material. Coalescence of initial clusters occurs at a thickness of 16 Å for atomically smooth hydrogen-terminated c-Si substrates, whereas on native oxide covered c-Si substrates the bulk volume void fractions are not reached until 35 Å film thickness. For the first time we present a series of IR transmission spectra with monolayer resolution of the initial growth of a-Si:H. Hereby the film thickness was measured simultaneously using a quartz crystal microbalance with corresponding sensitivity. The results give evidence for cluster formation with a coalescence radius of about 20 Å. Difference spectra calculated for layers at different depths with definite thickness reveal that the hydrogen-rich interface layer stays at the substrate surface and does not move with the surface of the growing film. The decrease of the Urbach energy switching from native oxide to H-terminated substrates suggests a strong influence of the interface morphology on the bulk material quality.

Measuring Reservoir Compaction Through Radioactive Marker Technique

2002 ◽  
Vol 124 (4) ◽  
pp. 269-275
Author(s):  
Paolo Macini ◽  
Ezio Mesini
Keyword(s):  
Land Subsidence ◽  
Reservoir Rock ◽  
Reservoir Compaction ◽  
Critical Comparison ◽  
In Situ Method ◽  
Sufficient Precision ◽  
Good Agreement

Radioactive Marker Technique (RMT), an in-situ method to measure reservoir rock compaction and to evaluate uniaxial compressibility coefficients Cm, is examined here. Recent field applications seems to confirm that RMT-derived Cm’s match with sufficient precision with those calculated from land subsidence observed over the field by means of geodetic surveys, but are not always in good agreement with those derived from lab measurements. In particular, here is reported an application of RMT in the Italian Adriatic offshore, which highlights the discrepancies of Cm’s measurements from lab and RMT. At present, these discrepancies aren’t thoroughly understood, so, from an applicative standpoint, it is still necessary to perform a critical comparison and integration between both set of data.

scholarly journals The influence of physical state on shikimic acid ozonolysis: a case for in situ microspectroscopy

2014 ◽  
Vol 14 (19) ◽  
pp. 10761-10772 ◽  
Author(s):  
S. S. Steimer ◽  
M. Lampimäki ◽  
E. Coz ◽  
G. Grzinic ◽  
M. Ammann
Keyword(s):  
Degradation Rate ◽  
Shikimic Acid ◽  
Bulk Material ◽  
Water Mixture ◽  
Gas Uptake ◽  
X Ray ◽  
Scanning Transmission ◽  
Dry Conditions ◽  
Semi Solid

Abstract. Atmospheric soluble organic aerosol material can become solid or semi-solid. Due to increasing viscosity and decreasing diffusivity, this can impact important processes such as gas uptake and reactivity within aerosols containing such substances. This work explores the dependence of shikimic acid ozonolysis on humidity and thereby viscosity. Shikimic acid, a proxy for oxygenated reactive organic material, reacts with O3 in a Criegee-type reaction. We used an environmental microreactor embedded in a scanning transmission X-ray microscope (STXM) to probe this oxidation process. This technique facilitates in situ measurements with single micron-sized particles and allows to obtain near-edge X-ray absorption fine structure (NEXAFS) spectra with high spatial resolution. Thus, the chemical evolution of the interior of the particles can be followed under reaction conditions. The experiments show that the overall degradation rate of shikimic acid is depending on the relative humidity in a way that is controlled by the decreasing diffusivity of ozone with decreasing humidity. This decreasing diffusivity is most likely linked to the increasing viscosity of the shikimic acid–water mixture. The degradation rate was also depending on particle size, most congruent with a reacto-diffusion limited kinetic case where the reaction progresses only in a shallow layer within the bulk. No gradient in the shikimic acid concentration was observed within the bulk material at any humidity indicating that the diffusivity of shikimic acid is still high enough to allow its equilibration throughout the particles on the timescale of hours at higher humidity and that the thickness of the oxidized layer under dry conditions, where the particles are solid, is beyond the resolution of STXM.

Sign in / Sign up

Export Citation Format

Share Document