scholarly journals Biodegradation and Microbial Contamination of Limestone Surfaces: An Experimental Study from Batalha Monastery, Portugal

2021 ◽  
Vol 2 (1) ◽  
pp. 31-45 ◽  
Author(s):  
Yufan Ding ◽  
Catia Sofia Clemente Salvador ◽  
Ana Teresa Caldeira ◽  
Emma Angelini ◽  
Nick Schiavon
Keyword(s):  
Experimental Study ◽  
Bacterial Communities ◽  
Air Pollutants ◽  
Metagenomic Dna ◽  
X Ray ◽  
Dna Test ◽  
Microbial Biofilms ◽  
Chemical Attack ◽  
Physical And Chemical ◽  
Microbial Samples

An experimental study was conducted to assess the nature and extent of the biodeterioration of the limestone in the Batalha Monastery in Portugal. Stone fragments covered with microbial biofilms and lichenous crusts were investigated using Optical Microscopy (OM), Low Vacuum Scanning Electron Microscopy with Energy Dispersive Spectroscopy (LV-SEM + EDS), and X-ray micro-Diffractometry (μ-XRD). Microbial samples were collected from the stone surface, cultured, and analyzed with NGS metagenomic DNA test to classify the bacterial communities associated with the formation of the biofilms. Particulate air pollutants collected on Pall GN-6 paper filters using a cascade impactor were characterized by SEM-EDS + NGS. The results showed that lichens play a major role in biodeterioration by promoting both physical and chemical attack on the limestone substrate via hyphae mechanical penetration along calcite inter-crystalline spaces, the dissolution/leaching of calcite minerals, and the precipitation of secondary minerals such as Ca-oxalates within the stone porosity framework. DNA analyses identified the bacterial communities within the biofilms and their relative abundances. Air quality monitoring results suggest that the microbial population colonizing the monastery limestone could at least partially be derived from the dry and wet deposition of airborne biological particles on the stone surfaces and that S, N, and P-rich air pollutants may have provided nutrients and energy for the bacteria communities, thus indirectly facilitating biofilm formation, the growth of a lichenous crusts, and limestone biodeterioration effects.

Identification of Particulate Air Pollutants and Contaminants by Scanning Electron Microscopy and X-ray Spectrometry

1971 ◽  
Vol 29 ◽  
pp. 62-63
Author(s):  
J. L. Price ◽  
T. L. Shirley
Keyword(s):  
Air Pollutants ◽  
Two Phase ◽  
X Ray ◽  
Phase Study ◽  
Particulate Pollutants ◽  
Leaf Surfaces ◽  
Definite Problem ◽  
Physical And Chemical ◽  
Palladium Metal ◽  
Scanning Electron

Although our knowledge of the effects of gaseous air pollutants on plants is expanding rapidly, little is known about the identification and effects of particulate air pollutants on plant surfaces. Accordingly, a two-phase study was undertaken: (a) to identify and characterize the various particulate pollutants and contaminants found on leaf surfaces; and (b) to determine their physical and chemical effects. This report describes the progress made in the first phase of this study.Using a Jeolco JSM-U3 scanning electron microscope with double dispersive X-ray spectrometers, observations were made on intact leaf surfaces (upper and lower) and on various particulate samples. Studies were made on various crop plants as well as on native chaparral and desert plants. Most of the samples were coated with approximately 50-100 Å of gold-palladium metal, since “charging” is a definite problem with particulate specimens.

Deterioration of Mortar Composites in Acidic Environment

2014 ◽  
Vol 1064 ◽  
pp. 3-8 ◽  
Author(s):  
M. Omrane ◽  
M. Mouli ◽  
A.S. Benosman ◽  
Y. Senhadji
Keyword(s):  
Experimental Study ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Acidic Environment ◽  
Acid Solutions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Aggressive Environment ◽  
Chemical Attack ◽  
Acidic Environments

In recent years, the rapid deterioration of various reinforced concrete structures has been widely recognized as worldwide problem. Acidic environments are very aggressive to concrete structures, as well as promote their degradation. The aim of this experimental study is to make a comparative analysis of the behavior of mortars prepared by cement (CPJ-CEM II/A) and composites of different percentage by weight of polymer. It highlights the influence of PET on the durability of these mortars. After 28 days of curing specimens in water, they are put in acid solutions of the same concentration 3% (HCl, H2SO4, H3PO4and HNO3). Weights tests measuring are made ​​at different ages. The results demonstrate the beneficial effect of the addition of PET in the modified materials against chemical attack by various acids. The formations which appear such as different calcium salts were determined by X-ray diffraction. These results take into account the recycling of plastic waste in the manufacture of modified mortars against aggressive environment.

scholarly journals Comparison of Synchrotron X-Ray Microanalysis with Electron and Proton Microscopy for Individual Particle Analysis

1991 ◽  
Vol 35 (B) ◽  
pp. 1265-1273
Author(s):  
K.H. Janssens ◽  
F. van Langevelde ◽  
F.C. Adams ◽  
R.D. Vis ◽  
S.R. Sutton ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Gas Phase ◽  
Air Pollutants ◽  
Chemical Characterization ◽  
Particle Analysis ◽  
Characterization Methods ◽  
X Ray ◽  
Physical And Chemical Characterization ◽  
Individual Particle Analysis ◽  
Physical And Chemical

A considerable number of the elements and a profusion of organic compounds are emitted into the atmosphere in association with solid and liquid particles. More than 50 percent of all air pollutants are preferentially present in particulate matter rather than in the gas phase. The assessment of the potential environmental and toxic effects of particulate matter in the atmosphere requires a detailed physical and chemical characterization. Methods for analyzing aerosols have recently been extensively reviewed by Maenhaut.

Characterization of defects in tabular silver halide grains

1990 ◽  
Vol 48 (4) ◽  
pp. 1046-1047
Author(s):  
C. Goessens ◽  
D. Schryvers ◽  
J. Van Landuyt ◽  
A. Verbeeck ◽  
R. De Keyzer
Keyword(s):  
Radiation Damage ◽  
Silver Halide ◽  
Chemical Characteristics ◽  
X Ray ◽  
Free Region ◽  
Central Defect ◽  
Crystallographic Defects ◽  
Physical And Chemical ◽  
Two Sides

Silver halide grains (AgX, X=Cl,Br,I) are commonly recognized as important entities in photographic applications. Depending on the preparation specifications one can grow cubic, octahedral, tabular a.o. morphologies, each with its own physical and chemical characteristics. In the present study crystallographic defects introduced by the mixing of 5-20% iodide in a growing AgBr tabular grain are investigated. X-ray diffractometry reveals the existence of a homogeneous Ag(Br1-xIx) region, expected to be formed around the AgBr kernel. In fig. 1 a two-beam BF image, taken at T≈100 K to diminish radiation damage, of a triangular tabular grain is presented, clearly showing defect contrast fringes along four of the six directions; the remaining two sides show similar contrast under relevant diffraction conditions. The width of the central defect free region corresponds with the pure AgBr kernel grown before the mixing with I. The thickness of a given grain lies between 0.15 and 0.3 μm: as indicated in fig. 2 triangular (resp. hexagonal) grains exhibit an uneven (resp. even) number of twin interfaces (i.e., between + and - twin variants) parallel with the (111) surfaces. The thickness of the grains and the existence of the twin variants was confirmed from CTEM images of perpendicular cuts.

An Experimental Study on Bond between Porcelain and Gold : Observation with Fine Focus X-ray Generator (Part 1)

1978 ◽  
Vol 31 (5) ◽  
pp. 425-431
Author(s):  
Shigeki Murakami ◽  
Yasunari Uchida ◽  
Yoshinori Chikaura
Keyword(s):  
Experimental Study ◽  
X Ray ◽  
Fine Focus

scholarly journals Composite Material of PDMS with Interchangeable Transmittance: Study of Optical, Mechanical Properties and Wettability

2021 ◽  
Vol 5 (4) ◽  
pp. 110
Author(s):  
Flaminio Sales ◽  
Andrews Souza ◽  
Ronaldo Ariati ◽  
Verônica Noronha ◽  
Elder Giovanetti ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Room Temperature ◽  
Casting Process ◽  
Optical Characteristics ◽  
Smart Devices ◽  
Superhydrophobic Coating ◽  
Gravity Casting ◽  
High Flexibility ◽  
Physical And Chemical

Polydimethylsiloxane (PDMS) is a polymer that has attracted the attention of researchers due to its unique properties such as transparency, biocompatibility, high flexibility, and physical and chemical stability. In addition, PDMS modification and combination with other materials can expand its range of applications. For instance, the ability to perform superhydrophobic coating allows for the manufacture of lenses. However, many of these processes are complex and expensive. One of the most promising modifications, which consists of the development of an interchangeable coating, capable of changing its optical characteristics according to some stimuli, has been underexplored. Thus, we report an experimental study of the mechanical and optical properties and wettability of pure PDMS and of two PDMS composites with the addition of 1% paraffin or beeswax using a gravity casting process. The composites’ tensile strength and hardness were lower when compared with pure PDMS. However, the contact angle was increased, reaching the highest values when using the paraffin additive. Additionally, these composites have shown interesting results for the spectrophotometry tests, i.e., the material changed its optical characteristics when heated, going from opaque at room temperature to transparent, with transmittance around 75%, at 70 °C. As a result, these materials have great potential for use in smart devices, such as sensors, due to its ability to change its transparency at high temperatures.

scholarly journals Physical and chemical imaging of adhesive interfaces with soft X-rays

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Hiroyuki Yamane ◽  
Masaki Oura ◽  
Osamu Takahashi ◽  
Tomoko Ishihara ◽  
Noriko Yamazaki ◽  
...  
Keyword(s):  
Molecular Level ◽  
Covalent Bond ◽  
Chemical Imaging ◽  
Diglycidyl Ether ◽  
X Rays ◽  
X Ray ◽  
Covalent Bond Formation ◽  
Chemical States ◽  
The Individual ◽  
Physical And Chemical

AbstractAdhesion is an interfacial phenomenon that is critical for assembling carbon structural composites for next-generation aircraft and automobiles. However, there is limited understanding of adhesion on the molecular level because of the difficulty in revealing the individual bonding factors. Here, using soft X-ray spectromicroscopy we show the physical and chemical states of an adhesive interface composed of a thermosetting polymer of 4,4’-diaminodiphenylsulfone-cured bisphenol A diglycidyl ether adhered to a thermoplastic polymer of plasma-treated polyetheretherketone. We observe multiscale phenomena in the adhesion mechanisms, including sub-mm complex interface structure, sub-μm distribution of the functional groups, and molecular-level covalent-bond formation. These results provide a benchmark for further research to examine how physical and chemical states correlate with adhesion, and demonstrate that soft X-ray imaging is a promising approach for visualizing the physical and chemical states at adhesive interfaces from the sub-mm level to the molecular level.

Russellite: a second occurrence

1970 ◽  
Vol 37 (290) ◽  
pp. 705-707 ◽  
Author(s):  
L. C. Hodge
Keyword(s):  
Powder Diffraction ◽  
Western Australia ◽  
Original Description ◽  
Chemical Data ◽  
Green Material ◽  
X Ray ◽  
Fine Grained ◽  
Physical And Chemical ◽  
Pale Green

SummaryRussellite Bi2O3. WO3 occurs in a small pegmatite near Poona, Western Australia. The fine-grained yellow to pale green material is an inseparable mixture of russellite, bismite, koechlinite, and bismutite. X-ray powder diffraction, physical, and chemical data agree in general with the original description of the mineral from Cornwall, England. The original analyses made on micro quantities are now supplemented by analyses on macro quantities.

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