Longevity of Borehole and Shaft Sealing Materials: Characterization of Ancient Cement Based Building Materials

1983 ◽  
Vol 26 ◽  
Author(s):  
Christine A. Langton ◽  
Della M. Roy
Keyword(s):  
Nuclear Waste ◽  
Building Materials ◽  
Materials Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Long Term Stability ◽  
Sealing Materials ◽  
National Effort

ABSTRACTDurability and long-term stability of cements in plasters, mortars, and/or concretes utilized as borehole plugging and shaft sealing materials are of present concern in the national effort to isolate nuclear waste within deep geological repositories. The present study consists of an examination of selected ancient building materials and provides insights into the durability of certain ancient structures. These data were combined with knowledge obtained from the behavior of modern portland cements and natural materials to evaluate the potential for longevity of such materials in a borehole environment. Analyses were conducted by petrographic, SEM, chemical, and x-ray diffraction techniques.

Structural characterization of free-standing gallium arsenide coiled membranes produced by micromachining

1999 ◽  
Vol 32 (1) ◽  
pp. 60-64
Author(s):  
Krishan Lal ◽  
S. Niranjana N. Goswami ◽  
J. Miao ◽  
H. L. Hartnagel
Keyword(s):  
High Resolution ◽  
Beam Width ◽  
Thin Strip ◽  
X Ray Diffraction ◽  
Free Standing ◽  
X Ray ◽  
Long Term Stability ◽  
Diffraction Peaks

High-resolution X-ray diffraction techniques have been employed successfully to evaluate crystalline quality and long-term stability of coiled membranes. The process of fabrication involves photolithography, implantation by 2 MeV N^{2+} ions inn-type GaAs substrates, followed by selective etching. A five-crystal X-ray diffractometer was employed in (+, −, +) setting with an Mo Kα1exploring beam for high-resolution X-ray diffractometry and topography experiments. The exploring-beam width was reduced to illuminate different segments of the coiled membrane. Diffraction curves recorded from the bulk crystal surrounding the sensor had a half width of 26 arcseconds, whereas the half widths from sensor segments were in the range ∼58 to ∼166 arcseconds. Different segments (particularly vertical ones) were identified from the observed angular separations between different diffraction peaks as well as from the shape of the diffraction peaks. It was found that different segments of the sensor were tilted with respect to one another and the tilt angles were in the range 15–212 arcseconds. High-resolution X-ray diffraction topographs recorded from (5\bar 11) and (400) diffracting planes revealed that the sides of the trough below the membrane created by etching are not vertical, but tapered. Also, there is a thin strip of crystal freely hanging over the tapered regions as a result of underetching. The surface of the cavity is uneven. The structural perfection of different membrane segments could also be ascertained from the contrast in topographs.

Synthesis of Trilaminar Core–Shell Au/α-Fe2O3@SnO2Nanocomposites and their Application for Nonenzymatic Dopamine Electrochemical Sensing

NANO ◽  
2019 ◽  
Vol 14 (11) ◽  
pp. 1950138 ◽  
Author(s):  
Sai Zhang ◽  
Shijun Yue ◽  
Jiajia Li ◽  
Jianbin Zheng ◽  
Guojie Gao
Keyword(s):  
Electron Microscopy ◽  
High Sensitivity ◽  
Electrochemical Sensing ◽  
Synthesis Process ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Long Term Stability ◽  
Transmission Electron

Au nanoparticles anchored on core–shell [Formula: see text]-Fe2O3@SnO2 nanospindles were successfully constructed through hydrothermal synthesis process and used for fabricating a novel nonenzymatic dopamine (DA) sensor. The structure and morphology of the Au/[Formula: see text]-Fe2O3@SnO2 trilaminar nanohybrid film were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The electrochemical properties of the sensor were investigated by cyclic voltammetry and amperometry. The experimental results suggest that the composites have excellent catalytic property toward DA with a wide linear range from 0.5[Formula: see text][Formula: see text]M to 0.47[Formula: see text]mM, a low detection limit of 0.17[Formula: see text][Formula: see text]M (S/[Formula: see text]) and high sensitivity of 397.1[Formula: see text][Formula: see text]A[Formula: see text]mM[Formula: see text][Formula: see text]cm[Formula: see text]. In addition, the sensor exhibits long-term stability, good reproducibility and anti-interference.

Carbon Dioxide Reforming of Methane over Ni/Mo/La2O3-SBA-15 Сatalyst

2012 ◽  
Vol 455-456 ◽  
pp. 960-965
Author(s):  
Jian Huang ◽  
T. Huang ◽  
A. Rongzhang ◽  
Wei Huang ◽  
Ren Xiong Ma
Keyword(s):  
Carbon Dioxide ◽  
Strong Interaction ◽  
Carbon Deposition ◽  
Catalytic Performance ◽  
Stability Test ◽  
X Ray Diffraction ◽  
Carbon Dioxide Reforming ◽  
X Ray ◽  
Long Term Stability

Carbon dioxide reforming of methane over Ni/Mo/ La2O3-SBA-15 was studied. The catalyst was characterized by N2 adsorption, X-ray diffraction, H2-TPR,CO2-TPD and TG-GTA analysis. The results indicated that the introduction of an appropriate amount of La2O3 exhibited a higher activity and stability. In the long term stability test, La2O3 impregnated Ni/Mo-SBA-15 gave the highest conversion and stable activity at 800°C for 250 h. The effect of La was suggested to be due to its lower tendency to carbon deposition. Characterization results showed a strong interaction between La and Mo or Ni which facilitated the improvement of catalytic performance.

scholarly journals Preparation, Modification, and Characterization of Alginate Hydrogel with Nano-/Microfibers: A New Perspective for Tissue Engineering

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Bianca Palma Santana ◽  
Fernanda Nedel ◽  
Evandro Piva ◽  
Rodrigo Varella de Carvalho ◽  
Flávio Fernando Demarco ◽  
...  
Keyword(s):  
Cell Viability ◽  
Chemical Properties ◽  
Chemical Characteristics ◽  
X Ray Diffraction ◽  
Alginate Hydrogel ◽  
X Ray ◽  
New Perspective ◽  
Nih 3T3

We aimed to develop an alginate hydrogel (AH) modified with nano-/microfibers of titanium dioxide (nfTD) and hydroxyapatite (nfHY) and evaluated its biological and chemical properties. Nano-/microfibers of nfTD and nfHY were combined with AH, and its chemical properties were evaluated by FTIR spectroscopy, X-ray diffraction, energy dispersive X-Ray analysis, and the cytocompatibility by the WST-1 assay. The results demonstrate that the association of nfTD and nfHY nano-/microfibers to AH did not modified the chemical characteristics of the scaffold and that the association was not cytotoxic. In the first 3 h of culture with NIH/3T3 cells nfHY AH scaffolds showed a slight increase in cell viability when compared to AH alone or associated with nfTD. However, an increase in cell viability was observed in 24 h when nfTD was associated with AH scaffold. In conclusion our study demonstrates that the combination of nfHY and nfTD nano-/microfibers in AH scaffold maintains the chemical characteristics of alginate and that this association is cytocompatible. Additionally the combination of nfHY with AH favored cell viability in a short term, and the addition of nfTD increased cell viability in a long term.

Baustoffanalyse mit Infrarotspektroskopie / Analysis of building materials by infrared spectroscopy

1998 ◽  
Vol 4 (3) ◽  
pp. 209-232
Author(s):  
R. Salzer ◽  
R. Lunkwitz ◽  
T. Braun ◽  
M. Mühle
Keyword(s):  
Building Materials ◽  
Molecular Spectroscopy ◽  
Spectroscopic Measurement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Modern Methods ◽  
Wet Chemical ◽  
Ir Spectroscopic ◽  
Instrumental Methods

Abstract Modern methods of instrumental analysis provide very convenient ways to characterize building materials. At present, wet chemical procedures are still in use not only for sample preparation but also for the real investigation. Raster electron microsopy and x-ray diffraction are the preferred instrumental methods of analysis in many places. In this review the high potential of optical molecular spectroscopy for characterization of building materials will be demonstrated by typical examples. Extensive series of wet chemical analysis may be substituted even by a single IR spectroscopic measurement combined with modern procedures of chemometric data evaluation.

scholarly journals Graphene Langmuir-Schaefer films Decorated by Pd Nanoparticles for NO2 and H2 Gas Sensors

2019 ◽  
Vol 19 (2) ◽  
pp. 64-69 ◽  
Author(s):  
Dmytro Kostiuk ◽  
Stefan Luby ◽  
Peter Siffalovic ◽  
Monika Benkovicova ◽  
Jan Ivanco ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Pd Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Si Substrates ◽  
Long Term Stability ◽  
Atomic Force ◽  
Few Layer Graphene

Abstract NO2 and H2 gas sensing by few-layer graphene (FLG) were studied in dependence on the annealing and decoration of graphene by palladium nanoparticles (NPs). Graphene was deposited onto SiO2 (500 nm)/Si substrates by a modified Langmuir-Schaefer technique. A solution of FLG flakes in 1-methyl-2-pyrrolidone was obtained by a mild sonication of the expanded milled graphite. FLG films were characterized by atomic force microscopy, X-ray diffraction, Raman spectroscopy, and the Brunnauer-Emmett-Teller method. Average FLG flake thickness and lateral dimension were 5 nm and 300 nm, respectively. Drop casting of Pd NP (6–7 nm) solution onto FLG film was applied to decorate graphene by Pd. The room temperature (RT) resistance of the samples was stabilized at 15 kΩ by vacuum annealing. Heating cycles of FLG film revealed its semiconducting character. The gas sensing was tested in the mixtures of dry air with H2 gas (10 to 10 000 ppm) and NO2 gas (2 to 200 ppm) between RT and 200 °C. The response of 26 % to H2 was achieved by FLG with Pd decoration at 70 °C and 10 000 ppm of H2 in the mixture. Pure FLG film did not show any response to H2. The response of FLG with Pd to 6 ppm of NO2 at RT was ≥ 23 %. It is 2 times larger than that of the pure FLG sample. Long term stability of sensors was studied.

Preparation and Characterization of Electrochemical Glucose Sensor Based on Nickel Electrodes Supported by Silicon Microchannel Plates

2011 ◽  
Vol 138-139 ◽  
pp. 1126-1131
Author(s):  
Bai Rui Tao ◽  
Feng Juan Miao ◽  
Yong Jie Zheng
Keyword(s):  
Glucose Sensor ◽  
Electrochemical Etching ◽  
Alkaline Solutions ◽  
X Ray Diffraction ◽  
Long Term Stability ◽  
Microchannel Plates ◽  
Electro Oxidation ◽  
Oxidation Of Glucose

A novel nickel nanocomposite electrode supported by 3D ordered silicon microchannel plates (MCP) had been reported and its electrocatalytic toward the oxidation of glucose for sensor had been studied. The 3D ordered Si MCP electrodes were first fabricated by electrochemical etching and then Nickel nanoparticles were deposited onto the sidewall of the MCP via electroless deposition followed by annealing at 300°C for 300 s under argon to stabilize the structure. The morphology of the Ni/Si-MCP electrode was characterized by Scanning electron microscope (SEM) and X-ray diffraction (XRD). The electrochemical methods were employed to investigate the Ni/Si-MCP materials. The Ni/Si-MCP nanocomposites exhibit superior electrocatalytic properties towards glucose electro-oxidation in alkaline solutions, in addition to showing excellent long-term stability and good reproducibility.

Characterization of an X-ray mirror mechanical bender for the European XFEL

2016 ◽  
Vol 23 (4) ◽  
pp. 855-860 ◽  
Author(s):  
Maurizio Vannoni ◽  
Idoia Freijo Martín ◽  
Harald Sinn
Keyword(s):  
Radius Of Curvature ◽  
Cylindrical Shape ◽  
Mirror Surface ◽  
Fizeau Interferometer ◽  
X Ray ◽  
Optical Setup ◽  
Long Term Stability ◽  
Large Aperture

One of the classical devices used to tune a mirror on an X-ray optical setup is a mechanical bender. This is often designed in such a way that the mirror is held with clamps on both ends; a motor is then used to put a torque on the clamps, inducing a cylindrical shape of the mirror surface. A mechanical bender with this design was recently characterized, to bend a 950 mm-long mirror up to a radius of curvature of 10 km. The characterization was performed using a large-aperture Fizeau interferometer with an angled incidence setup. Some particular and critical effects were investigated, such as calibration, hysteresis, twisting and long-term stability.

Dissolution of used Candu Fuel at Various Temperatures and Redox Conditions

1985 ◽  
Vol 50 ◽  
Author(s):  
S. Stroes-Gascoyne ◽  
L. H. Johnson ◽  
P. A. Beeley ◽  
D. M. Sellinger
Keyword(s):  
Potential Importance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Long Term Stability ◽  
Saturated Water ◽  
Reducing Conditions ◽  
Release Studies ◽  
Show Evidence ◽  
Radionuclide Release

AbstractSamples of used UO2 fuel exposed to air-saturated water at 25°C for eight years have been examined using electron microscopy and X-ray diffraction techniques. The results, in conjunction with solution analysis uata, show evidence for a UO3.2H2O precipitate on the fuel surface, and confirm the importance of grain-boundary leaching in controlling Cs-137 release. Studies of useo-fuel dissolution under both oxidizing and reducing conditions at 150°C show significantly lower radionuclide release to solution for reducing conditions, illustrating the potential importance of reoox chemistry in determining the long-term stability of used fuel after disposal.

scholarly journals The long-term stability of residual stresses in steel

2021 ◽  
Vol 3 (12) ◽  
Author(s):  
Eckehard Mueller
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Compressive Residual Stress ◽  
List Type ◽  
X Ray Diffraction ◽  
X Ray ◽  
Term Stability ◽  
Long Term Stability ◽  
The Stability

Abstract There is frequent debate over the long-term stability of calibration specimens. It is an essential component of monitoring, especially for X-ray diffraction equipment used to determine residual stresses. If residual stresses are stable, a second consideration is that the residual stress should not be close to 0 MPa. If such specimens are available for monitoring, it is more sensitive concerning changes. These are key requirements when developing calibration specimens. In this study five specimens were observed, one of them was tested for more than 20 years. The stresses were determined with X-ray diffractometers. In the last four years two different X-ray methods for determination were used. It can be shown that high compressive residual stress does not change in steel if the specimens had no dynamic or static load and were stored under normal laboratory conditions. Article Highlights Finding a material in which compressive residual stress is stable Showing that the stability of compressive residual stress is over a long term The stability of the compressive residual stress is in a great range

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