Soft x-ray reflectivity-enhancement in astronomical telescopes via overcoatings: alternative materials and deposition methods

2019 ◽  
Author(s):  
Giovanni Pareschi ◽  
Marta Maria Civitani ◽  
Giorgia Sironi ◽  
Yang Yang ◽  
Vincenzo Cotroneo ◽  
...  
Keyword(s):  
X Ray ◽  
Alternative Materials

New lightweight x-ray optics: alternative materials

2009 ◽  
Author(s):  
M. Skulinova ◽  
R. Hudec ◽  
J. Sik ◽  
M. Lorenc ◽  
L. Pina ◽  
...  
Keyword(s):  
Ray Optics ◽  
X Ray ◽  
Alternative Materials

Alternative materials in view of new light weight x-ray optics

2009 ◽  
Author(s):  
M. Skulinova ◽  
R. Hudec ◽  
J. Sik ◽  
M. Lorenc ◽  
L. Pina ◽  
...  
Keyword(s):  
Light Weight ◽  
Ray Optics ◽  
X Ray ◽  
Alternative Materials

Soil-Lime Blocks Using Construction Residues - Durability Study

2012 ◽  
Vol 727-728 ◽  
pp. 1422-1427
Author(s):  
Suélen Silva Figueiredo ◽  
Cibelle Guimarães Silva ◽  
Izabelle Marie Trindade Bezerra ◽  
Suellen Lisboa Dias ◽  
Gelmires Araújo Neves ◽  
...  
Keyword(s):  
Construction Industry ◽  
Raw Materials ◽  
Raw Material ◽  
Partial Replacement ◽  
Distribution Analysis ◽  
X Ray Diffraction ◽  
New Techniques ◽  
X Ray ◽  
Curing Period ◽  
Alternative Materials

The construction industry in addition to being considered one of the biggest natural resources consumers is still responsible for generating large quantities of residues. The impacts caused by these residues have motivated research aimed at developing new techniques for reuse and recycling this material by using as raw material to make alternative materials. The introduction of demolition residues (DR) in soil-lime bricks replacing part of the pozzolan becomes possible due to the cementing properties that these residues may present when finely grounded. This study aims to evaluate the durability of soil-lime blocks embedded with demolition residues. For this study the raw materials were characterized by particle size distribution analysis, X-ray diffraction and chemical analysis. Then test specimens were prepared using mixes in a 1:10 ratio of lime:soil and embedded with residue in partial replacement of lime, in the proportions of 25%, 50% and 75% with curing period of 90 days. Later, the test specimens were evaluated for durability. The results showed that soil-lime bricks embedded with contents above 50% of residues had their durability affected.

scholarly journals Study of the effect of diatomite on physico-mechanical properties of concrete

Cerâmica ◽  
2020 ◽  
Vol 66 (377) ◽  
pp. 50-55
Author(s):  
A. R. S. Macedo ◽  
A. S. Silva ◽  
D. S. da Luz ◽  
R. L. S. Ferreira ◽  
C. S. Lourenço ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Silica Content ◽  
Mass Concrete ◽  
High Porosity ◽  
X Ray Diffraction ◽  
Specific Mass ◽  
X Ray ◽  
Alternative Materials ◽  
Fine Particle Size

Abstract Concretes present great potential to be used in many areas of civil construction. Their properties can be improved by substitution or addition of alternative materials to the Portland cement. The diatomite is a sedimentary material composed mainly by silica and amorphous impurities, presenting very fine particle size, high porosity, and low specific mass. Concrete was produced in a ratio of 1:1:2 (cement: sand: gravel) with the addition of diatomite at contents of 5% and 10% by cement weight and a water/cement ratio of 0.54. The physico-mechanical properties of the concretes were evaluated by tests of compressive strength and water absorption by immersion. Also, X-ray diffraction and scanning electron microscopy were carried out to analyze the main phases in the cement paste. The results indicated that the addition of diatomite in the concrete increased the compressive strength due to the silica content in the material and reduced slightly the porosity.

scholarly journals The electronic structure and band interface of cesium bismuth iodide on a titania heterostructure using hard X-ray spectroscopy

2018 ◽  
Vol 6 (20) ◽  
pp. 9498-9505 ◽  
Author(s):  
Dibya Phuyal ◽  
Sagar M. Jain ◽  
Bertrand Philippe ◽  
Malin B. Johansson ◽  
Meysam Pazoki ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Solar Cells ◽  
X Ray ◽  
Bismuth Iodide ◽  
Alternative Materials

Bismuth halide compounds are a non-toxic alternative materials for solar cells and show promise in devices.

scholarly journals Effect of different sources of alumina on the microstructure and mechanical properties of the triaxial porcelain

Cerâmica ◽  
2014 ◽  
Vol 60 (356) ◽  
pp. 471-481 ◽  
Author(s):  
G. Gralik ◽  
A. L. Chinelattot ◽  
A. S. A. Chinelatto
Keyword(s):  
Mechanical Properties ◽  
Aluminum Hydroxide ◽  
Raw Materials ◽  
Primary Aluminum ◽  
Mechanical Resistance ◽  
Alternative Source ◽  
X Ray ◽  
Alternative Materials ◽  
Alumina Refractory ◽  
Different Sources

Porcelains composed of kaolin-quartz-feldspar are called triaxial porcelains. The use of alumina as a substitute for quartz in porcelains has been developed for some time. The results show a significant improvement in their mechanical properties, but alumina has a high cost. The possibility of using alternative materials as a source of alumina with lower cost was investigated. In this work, alternative raw materials were used as a source of alumina: refractory bauxite, primary aluminum hydroxide, reprecipitated aluminum hydroxide. Compositions with commercial alumina and quartz were also formulated to better understand the effects of adding these alternative materials. The raw materials were milled, dried, and characterized by analysis of the particle size distribution, X-ray diffraction, and X-ray fluorescence. The compositions were formulated by replacing the different sources of alumina in the formulation of porcelain. The compositions studied were shaped by pressing and sintered at different temperatures (1150-1400 ºC). The results showed that the use of bauxite and aluminum hydroxide as an alternative source of Al2O3 is viable. The impurities contained in refractory bauxite contributed to the lower values of flexural strength found in compositions having refractory bauxite as a source of alumina. The compositions with reprecipitated aluminum hydroxide showed a high mechanical resistance at low sintering temperatures, while compositions with aluminum hydroxide obtained by the Bayer process achieved good results of mechanical strength in a wide temperature range.

The Effects of Biochar Additive on the Properties of Geopolymer Materials

2019 ◽  
Vol 798 ◽  
pp. 273-278
Author(s):  
Phitchayanin Khamlue ◽  
Narumon Lertcumfu ◽  
Pharatree Jaita ◽  
Supalak Manotham ◽  
Tawee Tunkasiri ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Exchange Capacity ◽  
Pollutant Removal ◽  
X Ray Diffraction ◽  
Ion Exchange Capacity ◽  
X Ray ◽  
Alternative Materials ◽  
Alkaline Activator ◽  
Materials Used ◽  
Interesting Alternative

In this research, the effects of biochar additive on the properties of geopolymer materials were investigated. Normally, the geopolymer can be used for adsorption materials due to good ion exchange capacity. Biochar also has the application as an adsorption material for pollutant removal. Biochar particles were prepared from waste materials in pyrolysis condition. The geopolymer materials were prepared by mixing metakaolin and aluminium oxide in alkaline activator solutions of Na2SiO3and NaOH. Biochar was mixed with geopolymer by 0, 10, 20, and 30 % weight of binder. A NaOH concentration of 15 M, and Na2SiO3/NaOH ratios of 1.5 by weight were used. The density, porosity, and water absorption were measured. The phase formation, microstructure, and bonds of the sample were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). The adsorption capacity of each sample was determined by methylene blue adsorption tests. The result of the removal efficiency of all samples shows high adsorption capacity (60-70 %). It should be interesting alternative materials used for remove of aqueous solution.

Polycrystalline Lead Iodide Films: Optical, Electrical and X-ray Counting Characterization

2001 ◽  
Vol 685 ◽  
Author(s):  
L. Fornaro ◽  
E. Saucedo ◽  
L. Mussio ◽  
A. Gancharov ◽  
F. Guimaraes ◽  
...  
Keyword(s):  
Physical Vapor Deposition ◽  
Peak Position ◽  
Polycrystalline Films ◽  
Lead Iodide ◽  
X Ray ◽  
Force Microscopy ◽  
Material Deposition ◽  
Deposition Parameters ◽  
Average Grain Size ◽  
Alternative Materials

AbstractLead iodide purified by zone refining and repeated sublimation was used for growing Polycrystalline films by physical vapor deposition. Palladium film was deposited as rear contact onto glass and alumina substrates 2.5 × 2.5 cm2 in size. Onto it, lead iodide polycrystalline films were grown by sublimation at 390 °C and 5 × 10−5 mm Hg, substrate temperatures of about 200 °C and deposition times of about 10 days. Film thickness was measured by X-ray transmission at 59.5 keV giving values from 35 to 50 μm (5%). Optical and atomic force microscopy were performed to the films giving an average grain size of (80±20) μm. Low temperature photoluminescence was performed and peak position and broadness confirmed the high purity of starting materials. Films were characterized by X-ray diffraction, giving an [ΣI (0 0 l)] / [ΣI (h k l)] relation of 0.8 that indicates a strong growth preferred orientation along c axis. Front palladium thermal deposition contacts and acrylic encapsulation were done and apparent resistivity (2 × 1014 Ω. cm) and current density (7 pA/cm2 (30 V)) were obtained. X-ray film response was checked by irradiating with 241Am and an X-ray beam. Finally, film and detector characterizations were correlated with starting material, deposition parameters and previous results for the same and alternative materials like mercuric iodide.

Space and Time Distribution of Hard X-Ray Emission in a Loop at the Beginning of a Flare

1994 ◽  
Vol 144 ◽  
pp. 275-277
Author(s):  
M. Karlický ◽  
J. C. Hénoux
Keyword(s):  
Time Distribution ◽  
Electron Bombardment ◽  
Spatial Evolution ◽  
Superthermal Electrons ◽  
Flare Loop ◽  
X Ray ◽  
Superthermal Electron ◽  
Flare Loops ◽  
Chromospheric Evaporation ◽  
Temporal And Spatial

AbstractUsing a new ID hybrid model of the electron bombardment in flare loops, we study not only the evolution of densities, plasma velocities and temperatures in the loop, but also the temporal and spatial evolution of hard X-ray emission. In the present paper a continuous bombardment by electrons isotropically accelerated at the top of flare loop with a power-law injection distribution function is considered. The computations include the effects of the return-current that reduces significantly the depth of the chromospheric layer which is evaporated. The present modelling is made with superthermal electron parameters corresponding to the classical resistivity regime for an input energy flux of superthermal electrons of 109erg cm−2s−1. It was found that due to the electron bombardment the two chromospheric evaporation waves are generated at both feet of the loop and they propagate up to the top, where they collide and cause temporary density and hard X-ray enhancements.

Some Problems in Understanding the Solar Corona

1994 ◽  
Vol 144 ◽  
pp. 1-9
Author(s):  
A. H. Gabriel
Keyword(s):  
Solar Corona ◽  
Solar Atmosphere ◽  
Theoretical Modelling ◽  
Total System ◽  
Major Advance ◽  
X Ray ◽  
Proper Perspective ◽  
Space Observations

The development of the physics of the solar atmosphere during the last 50 years has been greatly influenced by the increasing capability of observations made from space. Access to images and spectra of the hotter plasma in the UV, XUV and X-ray regions provided a major advance over the few coronal forbidden lines seen in the visible and enabled the cooler chromospheric and photospheric plasma to be seen in its proper perspective, as part of a total system. In this way space observations have stimulated new and important advances, not only in space but also in ground-based observations and theoretical modelling, so that today we find a well-balanced harmony between the three techniques.

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