Diagnostic Techniques for PACVD Systems for Depositing Protective Coatings

1988 ◽  
Vol 117 ◽  
Author(s):  
Ward C. Roman ◽  
John H. Stufflebeam ◽  
Alan C. Eckbreth
Keyword(s):  
Protective Coatings ◽  
Plasma Chemistry ◽  
Diagnostic Techniques ◽  
Gas Temperature ◽  
Remote Sensors ◽  
Science Base ◽  
Starting Point ◽  
Plasma Species ◽  
Laser Diagnostic

AbstractPACVD techniques for depositing protective coatings are an emerging field in plasma processing technology. Technology transfer is limited by a lack of understanding of the basic mechanisms involved in the gas phase plasma chemistry. The aspects of plasma species concentration and distribution and plasma gas temperature are fragmentary and unclear. Laser diagnostic techniques represent a critical starting point for providing some of this needed information. The techniques are in-situ, nonintrusive, and give excellent spatial and temporal resolution. Numerous diagnostic techniques for detailed coating characterization are available, but a correlation of the PACVD parameters with some of the key coating properties is required. Thus, a predictive capability that is lacking in the present science base can be established together with important phenomenological aspects needed for efficient deposition of high quality protective coatings. As the mechanisms become better understood, use of remote sensors and A.I may then be introduced. This paper will review selected diagnostic techniques available for characterizing these nonequilibrium reactive plasmas and the coatings.

Laser/Optical Diagnostic Techniques for Plasma Materials Processing

1987 ◽  
Vol 98 ◽  
Author(s):  
Ward C. Roman
Keyword(s):  
Gas Phase ◽  
Synergistic Effects ◽  
Diagnostic Techniques ◽  
Materials Processing ◽  
Gas Temperature ◽  
Optical Diagnostic ◽  
Needed Information ◽  
Starting Point ◽  
Plasma Techniques

ABSTRACTThe application of plasma techniques is emerging as one of the more efficient means of processing materials. Technology transfer of plasma systems, both thermal and nonequilibrium, however, is severely limited by a lack of understanding of the basic mechanisms involved which govern the plasma processes used in many applications including advanced coatings. The aspects of plasma gas temperature, and species concentration and distribution (molecular, atomic, excited) in the gas phase and associated synergistic effects are fragmentary and unclear. Laser/optical diagnostic techniques represent a critical starting point for providing this needed information; they are in-situ, non-intrusive,species and quantum level specific and give excellent spatial and temporal resolution. A survey of Laser/optical diagnostic techniques applicable to plasma materials processing needs is presented. Some examples of the use of different techniques are also given.

scholarly journals Chemical Modification as a Method of Improving Biocompatibility of Carbon Nonwovens

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3198
Author(s):  
Justyna Frączyk ◽  
Sylwia Magdziarz ◽  
Ewa Stodolak-Zych ◽  
Ewa Dzierzkowska ◽  
Dorota Puchowicz ◽  
...  
Keyword(s):  
Surface Modification ◽  
Cellular Response ◽  
Fiber Surface ◽  
Thermal Conversion ◽  
Cartilage Tissue ◽  
Polar Component ◽  
Nonwoven Fabrics ◽  
Biological Compatibility ◽  
Starting Point

It was shown that carbon nonwoven fabrics obtained from polyacrylonitrile fibers (PAN) by thermal conversion may be modified on the surface in order to improve their biological compatibility and cellular response, which is particularly important in the regeneration of bone or cartilage tissue. Surface functionalization of carbon nonwovens containing C–C double bonds was carried out using in situ generated diazonium salts derived from aromatic amines containing both electron-acceptor and electron-donor substituents. It was shown that the modification method characteristic for materials containing aromatic structures may be successfully applied to the functionalization of carbon materials. The effectiveness of the surface modification of carbon nonwoven fabrics was confirmed by the FTIR method using an ATR device. The proposed approach allows the incorporation of various functional groups on the nonwovens’ surface, which affects the morphology of fibers as well as their physicochemical properties (wettability). The introduction of a carboxyl group on the surface of nonwoven fabrics, in a reaction with 4-aminobenzoic acid, became a starting point for further modifications necessary for the attachment of RGD-type peptides facilitating cell adhesion to the surface of materials. The surface modification reduced the wettability (θ) of the carbon nonwoven by about 50%. The surface free energy (SFE) in the chemically modified and reference nonwovens remained similar, with the surface modification causing an increase in the polar component (ɣp). The modification of the fiber surface was heterogeneous in nature; however, it provided an attractive site of cell–materials interaction by contacting them to the fiber surface, which supports the adhesion process.

On properties of seawater defined by temperature, salinity, and pressure

2021 ◽  
Vol 79 (3) ◽  
pp. 121-147
Author(s):  
George Veronis
Keyword(s):  
Vertical Direction ◽  
Great Depth ◽  
Local Potential ◽  
Potential Density ◽  
Marine Research ◽  
Station Data ◽  
Starting Point ◽  
The World ◽  
Gravitational Stability

Hydrographic station data, consisting principally of temperature and salinity determinations, have been used by physical oceanographers to develop a climatological picture of the distribution of these quantities in the oceans of the world. Density as determined by Knudsen's formula, taken together with hydrostatic and geostrophic dynamics, also provides a crude picture of oceanic flow. However, the data probably contain substantially more information than has been derived from them in the past.The quantity that is orthogonal to potential-density curves in the S plane is suggested as a useful variable to complement the information contained in potential density. The derivation of this quantity, denoted by τ in this paper, is straightforward. A polynomial expression for τ that is suitable for computer calculations of τ from hydrographic station data is given. Shown are examples of hydrographic station data from the Atlantic plotted on the τσ diagram. The information contained in the τσ diagram shows many of the features exhibited in the TS plane. Vertical sections of τ appear to provide information about mixing in different parts of the Atlantic. The distribution of τ for abyssal waters at selected stations in the oceans of the world resembles the distribution of abyssal density as plotted by Lynn and Reid (1968). From the data presented, it appears that τ may serve as a good tracer for abyssal water movements.Since τ is defined to be orthogonal to σ, the expectation is that τ is a dynamically passive variable. However, since σ does not correlate with abyssal densities, it appears to lose dynamical significance at great depth, and τ assumes dynamical significance because of its orthogonality to σ. This unexpected feature leads to an exploration of the dynamical significance of σ. A natural starting point is the question of stability of abyssal water.A distinction is made between stability as determined by in situ determinations and as determined by the potential-density (σ) distribution. Simple examples are presented to show that analysis based on σ alone can lead to incorrect conclusions about gravitational stability of the water in the abyssal ocean. The reason is that seawater is a multicomponent thermodynamic system, and the thermodynamic coefficients are functions of pressure, salinity, and temperature. This functional dependence leads to adjustments in density as a water particle moves adiabatically in the vertical direction so that a layer of water that appears to be unstable near the surface may be stable (as determined by in situ determination) at great depth. A local potential density, which is simply the vertical integral of the in situ stability, is derived. This quantity gives a precise picture of gravitational stability in the vertical direction. Some distributions of local potential density are shown.Originally published May 15, 1972, in the Journal of Marine Research 30(2), 227???255.

Heat Transfer to Oil Shale in a Closely Spaced Bundle as an Approximation to a Packed Bed

1981 ◽  
Vol 103 (4) ◽  
pp. 307-317
Author(s):  
K. S. Udell ◽  
H. R. Jacobs
Keyword(s):  
Heat Transfer ◽  
Oil Shale ◽  
Tube Bundle ◽  
Packed Bed ◽  
Cylindrical Sample ◽  
Chemical Processes ◽  
Published Data ◽  
Thermal Processes ◽  
Gas Temperature

The heat transfer to a single cylindrical sample of oil shale in a staggered tube bundle was studied both numerically and experimentally in order to evaluate the thermal and chemical processes associated with the retorting of oil shale in packed beds particular to in-situ processing. The cylinders were subjected to constant gas temperatures and to gas temperature histories experienced in an actual combustion retort. The results of the numerical modeling were compared with the experimental data in order to evaluate the model’s performance. It was found that the model satisfactorily described the thermal processes experienced during the combustion retorting of oil shale within the limits of the accuracy of published data on oil shale thermal properties and chemical kinetics. Net heat transfer to cylindrical oil shale samples in a staggered bundle configuration was also calculated and was shown to nearly duplicate published data related to gas-solid heat transfer in a packed bed combustion retort.

scholarly journals Testing the effect of water in crevasses on a physically based calving model

2012 ◽  
Vol 53 (60) ◽  
pp. 90-96 ◽  
Author(s):  
S. Cook ◽  
T. Zwinger ◽  
I.C. Rutt ◽  
S. O'Neel ◽  
T. Murray
Keyword(s):  
Finite Element ◽  
Water Depth ◽  
Surface Mass Balance ◽  
Two Dimensional ◽  
Finite Element Code ◽  
Surface Mass ◽  
Starting Point ◽  
Physically Based ◽  
Calving Rate

AbstractA new implementation of a calving model, using the finite-element code Elmer, is presented and used to investigate the effects of surface water within crevasses on calving rate. For this work, we use a two-dimensional flowline model of Columbia Glacier, Alaska. Using the glacier’s 1993 geometry as a starting point, we apply a crevasse-depth calving criterion, which predicts calving at the location where surface crevasses cross the waterline. Crevasse depth is calculated using the Nye formulation. We find that calving rate in such a regime is highly dependent on the depth of water in surface crevasses, with a change of just a few metres in water depth causing the glacier to change from advancing at a rate of 3.5 kma–1 to retreating at a rate of 1.9 km a–1. These results highlight the potential for atmospheric warming and surface meltwater to trigger glacier retreat, but also the difficulty of modelling calving rates, as crevasse water depth is difficult to determine either by measurement in situ or surface mass-balance modelling.

scholarly journals Fluorescence In Situ Hybridization (FISH) Analysis of the Locations of the Oligonucleotides 5S rDNA, (AGGGTTT)3, and (TTG)6 in Three Genera of Oleaceae and Their Phylogenetic Framework

Genes ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 375 ◽  
Author(s):  
Xiaomei Luo ◽  
Juncheng Liu
Keyword(s):  
In Situ Hybridization ◽  
Fluorescence In Situ Hybridization ◽  
5S Rdna ◽  
Fish Analysis ◽  
Cytogenetic Map ◽  
Ligustrum Lucidum ◽  
Starting Point ◽  
Central Regions ◽  
Almost All

We report the cytogenetic map for a collection of species in the Oleaceae, and test similarities among the karyotypes relative to their known species phylogeny. The oligonucleotides 5S ribosomal DNA (rDNA), (AGGGTTT)3, and (TTG)6 were used as fluorescence in situ hybridization (FISH) probes to locate the corresponding chromosomes in three Oleaceae genera: Fraxinus pennsylvanica, Syringa oblata, Ligustrum lucidum, and Ligustrum × vicaryi. Forty-six small chromosomes were identified in four species. (AGGGTTT)3 signals were observed on almost all chromosome ends of four species, but (AGGGTTT)3 played no role in distinguishing the chromosomes but displayed intact chromosomes and could thus be used as a guide for finding chromosome counts. (TTG)6 and 5S rDNA signals discerned several chromosomes located at subterminal or central regions. Based on the similarity of the signal pattern (mainly in number and location and less in intensity) of the four species, the variations in the 5S rDNA and (TTG)6 distribution can be ordered as L. lucidum < L. × vicaryi < F. pennsylvanica < S. oblata. Variations have observed in the three genera. The molecular cytogenetic data presented here might serve as a starting point for further larger-scale elucidation of the structure of the Oleaceae genome, and comparison with the known phylogeny of Oleaceae family.

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