H-Atom Assisted jet Vapor Deposition of Parylene-n polymer

1998 ◽  
Vol 544 ◽  
Author(s):  
B. L. Halpern ◽  
P. Komarenko ◽  
R. F. Graves ◽  
P. D. Fuqua ◽  
J. F. Mcdonald ◽  
...  
Keyword(s):  
Vapor Deposition ◽  
Atomic Hydrogen ◽  
Index Of Refraction ◽  
Small Scale ◽  
Slow Flow ◽  
Process Technology ◽  
New Approach ◽  
Jet Vapor Deposition ◽  
Parylene Film ◽  
Powerful Strategy

AbstractWe describe a new approach to deposition of Parylene N thin films. It utilizes a small scale, sonic speed, Jet Vapor DepositionTM (JVDTM) process technology in place of the conventional larger scale, slow flow, Gorham apparatus. It employs a simple but powerful strategy to promote radical polymerization: exposure of the growing film, during deposition, to a high flux of atomic hydrogen. We believe that H atoms have two effects: they clean oxygen from the substrate, and they promote crosslinking in the Parylene film by abstraction of H atoms from the Parylene ring or side groups. With “H atom assisted JVD” Parylene N deposits and adheres even on warm substrates; it has reduced index of refraction and dielectric constant.

scholarly journals A New Approach to Quantifying Bioaccumulation of Elements in Biological Processes

Biology ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 345
Author(s):  
Kinga Proc ◽  
Piotr Bulak ◽  
Monika Kaczor ◽  
Andrzej Bieganowski
Keyword(s):  
Element Concentration ◽  
Experimental System ◽  
Small Scale ◽  
New Approach ◽  
Realistic Situation ◽  
Initial Load ◽  
Test Elements ◽  
Organism Growth ◽  
Bioaccumulation Index ◽  
Phosphorous Concentration

Bioaccumulation, expressed as the bioaccumulation factor (BAF), is a phenomenon widely investigated in the natural environment and at laboratory scale. However, the BAF is more suitable for ecological studies, while in small-scale experiments it has limitations, which are discussed in this article. We propose a new indicator, the bioaccumulation index (BAI). The BAI takes into account the initial load of test elements, which are added to the experimental system together with the biomass of the organism. This offers the opportunity to explore the phenomena related to the bioaccumulation and, contrary to the BAF, can also reveal the dilution of element concentration in the organism. The BAF can overestimate bioaccumulation, and in an extremal situation, when the dilution of element concentration during organism growth occurs, the BAF may produce completely opposite results to the BAI. In one of the examples presented in this work (Tschirner and Simon, 2015), the concentration of phosphorous in fly larvae was lower after the experiment than in the younger larvae before the experiment. Because the phosphorous concentration in the feed was low, the BAF indicated a high bioaccumulation of this element (BAF = 14.85). In contrast, the BAI showed element dilution, which is a more realistic situation (BAI = −0.32). By taking more data into account, the BAI seems to be more valid in determining bioaccumulation, especially in the context of entomoremediation research.

Poststack impedance inversion considering the diffractive component of the wavefield

Geophysics ◽  
2020 ◽  
Vol 85 (1) ◽  
pp. R11-R28 ◽  
Author(s):  
Kun Xiang ◽  
Evgeny Landa
Keyword(s):  
Specular Reflection ◽  
Low Frequency ◽  
Velocity Model ◽  
Forward Modeling ◽  
Small Scale ◽  
Fracture Detection ◽  
Frequency Model ◽  
New Approach ◽  
Impedance Inversion ◽  
Diffraction Imaging

Seismic diffraction waveform energy contains important information about small-scale subsurface elements, and it is complementary to specular reflection information about subsurface properties. Diffraction imaging has been used for fault, pinchout, and fracture detection. Very little research, however, has been carried out taking diffraction into account in the impedance inversion. Usually, in the standard inversion scheme, the input is the migrated data and the assumption is taken that the diffraction energy is optimally focused. This assumption is true only for a perfectly known velocity model and accurate true amplitude migration algorithm, which are rare in practice. We have developed a new approach for impedance inversion, which takes into account diffractive components of the total wavefield and uses the unmigrated input data. Forward modeling, designed for impedance inversion, includes the classical specular reflection plus asymptotic diffraction modeling schemes. The output model is composed of impedance perturbation and the low-frequency model. The impedance perturbation is estimated using the Bayesian approach and remapped to the migrated domain by the kinematic ray tracing. Our method is demonstrated using synthetic and field data in comparison with the standard inversion. Results indicate that inversion with taking into account diffraction can improve the acoustic impedance prediction in the vicinity of local reflector discontinuities.

scholarly journals Inhomogeneous Mixing in Lagrangian Cloud Models: Effects on the Production of Precipitation Embryos

2018 ◽  
Vol 76 (1) ◽  
pp. 113-133 ◽  
Author(s):  
Fabian Hoffmann ◽  
Takanobu Yamaguchi ◽  
Graham Feingold
Keyword(s):  
Turbulent Mixing ◽  
Cloud Model ◽  
Small Scale ◽  
New Approach ◽  
Air Masses ◽  
Lagrangian Particles ◽  
Cloud Models ◽  
Large Eddy ◽  
Salutary Effect ◽  
Linear Eddy Model

Abstract Although small-scale turbulent mixing at cloud edge has substantial effects on the microphysics of clouds, most models do not represent these processes explicitly, or parameterize them rather crudely. This study presents a first use of the linear eddy model (LEM) to represent unresolved turbulent mixing at the subgrid scale (SGS) of large-eddy simulations (LESs) with a coupled Lagrangian cloud model (LCM). The method utilizes Lagrangian particles to provide the trajectory of air masses within LES grid boxes, while the LEM is used to redistribute these air masses among the Lagrangian particles based on the local features of turbulence, allowing for the appropriate representation of inhomogeneous to homogeneous SGS mixing. The new approach has the salutary effect of mitigating spurious supersaturations. At low turbulence intensities, as found in the early stages of an idealized bubble cloud simulation, cloud-edge SGS mixing tends to be inhomogeneous and the new approach is shown to be essential for the production of raindrop embryos. At higher turbulence intensities, as found in a field of shallow cumulus, SGS mixing tends to be more homogeneous and the new approach does not significantly alter the results, indicating that a grid spacing of 20 m may be sufficient to resolve all relevant scales of inhomogeneous mixing. In both cases, droplet in-cloud residence times are important for the production of precipitation embryos in the absence of small-scale inhomogeneous mixing, either naturally due to strong turbulence or artificially as a result of coarse resolution or by not using the LEM as an SGS model.

scholarly journals New Perspectives on the Urban–Rural Dichotomy and Dialect Contact in the Arabic gələt Dialects in Iraq and South-West Iran

Languages ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 198
Author(s):  
Bettina Leitner
Keyword(s):  
Comparative Analysis ◽  
Urban Space ◽  
Native Speakers ◽  
Small Scale ◽  
Alternative Analysis ◽  
Dialect Contact ◽  
New Approach ◽  
Geographic Context ◽  
Urban Rural

This paper reevaluates the ground on which the division into urban and rural gələt dialects, as spoken in Iraq and Khuzestan (south-western Iran), is built on. Its primary aim is to describe which features found in this dialect group can be described as rural and which features tend to be modified or to emerge in urban contexts, and which tend to be retained. The author uses various methodical approaches to describe these phenomena: (i) a comparative analysis of potentially rural features; (ii) a case study of Ahvazi Arabic, a gələt dialect in an emerging urban space; and (iii) a small-scale sociolinguistic survey on overt rural features in Iraqi Arabic as perceived by native speakers themselves. In addition, previously used descriptions of urban gələt features as described for Muslim Baghdad Arabic are reevaluated and a new approach and an alternative analysis based on comparison with new data from other gәlәt dialects are proposed. The comparative analysis yields an overview of what has been previously defined as rural features and additionally discusses further features and their association with rural dialects. This contributes to our general understanding of the linguistic profile of the rural dialects in this geographic context.

scholarly journals New Approach for Understanding the Oxidation Stability of Neopolyol Ester Lubricants Using a Small-Scale Oxidation Test Method

ACS Omega ◽  
2018 ◽  
Vol 3 (9) ◽  
pp. 10449-10459 ◽  
Author(s):  
Sandrine Duong ◽  
Nora Lamharess-Chlaft ◽  
Mickaël Sicard ◽  
Bruno Raepsaet ◽  
Maria Elena Galvez ◽  
...  
Keyword(s):  
Oxidation Stability ◽  
Test Method ◽  
Small Scale ◽  
New Approach ◽  
Oxidation Test

scholarly journals Precipitation Atlas for Germany (GePrA)

Atmosphere ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 737
Author(s):  
Christopher Jung ◽  
Dirk Schindler
Keyword(s):  
Spatial Resolution ◽  
Large Scale ◽  
High Spatial Resolution ◽  
Spline Interpolation ◽  
Absolute Error ◽  
Coefficient Of Determination ◽  
Small Scale ◽  
Monthly Precipitation ◽  
New Approach ◽  
Very High Spatial Resolution

A new approach for modeling daily precipitation (RR) at very high spatial resolution (25 m × 25 m) was introduced. It was used to develop the Precipitation Atlas for Germany (GePrA). GePrA is based on 2357 RR time series measured in the period 1981–2018. It provides monthly percentiles (p) of the large-scale RR patterns which were mapped by a thin plate spline interpolation (TPS). A least-squares boosting (LSBoost) approach and orographic predictor variables (PV) were applied to integrate the small-scale precipitation variability in GePrA. Then, a Weibull distribution (Wei) was fitted to RRp. It was found that the mean monthly sum of RR ( R R ¯ s u m ) is highest in July (84 mm) and lowest in April (49 mm). A great dependency of RR on the elevation (ε) was found and quantified. Model validation at 425 stations showed a mean coefficient of determination (R2) of 0.80 and a mean absolute error (MAE) of less than 10 mm in all months. The high spatial resolution, including the effects of the local orography, make GePrA a valuable tool for various applications. Since GePrA does not only describe R R ¯ s u m , but also the entire monthly precipitation distributions, the results of this study enable the seasonal differentiation between dry and wet period at small scales.

Low pressure chemical vapor deposition of B-N-C-H films from triethylamine borane complex

1995 ◽  
Vol 10 (2) ◽  
pp. 320-327 ◽  
Author(s):  
R.A. Levy ◽  
E. Mastromatteo ◽  
J.M. Grow ◽  
V. Paturi ◽  
W.P. Kuo ◽  
...  
Keyword(s):  
Activation Energy ◽  
Growth Rate ◽  
Chemical Vapor Deposition ◽  
Apparent Activation Energy ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Low Pressure ◽  
Index Of Refraction ◽  
Arrhenius Behavior ◽  
Pressure Chemical

In this study, films consisting of B-N-C-H have been synthesized by low pressure chemical vapor deposition using the liquid precursor triethylamine borane complex (TEAB) both with and without ammonia. When no NH3 is present, the growth rate was observed to follow an Arrhenius behavior in the temperature range of 600 to 800 °C with an apparent activation energy of 11 kcal/mol. A linear dependence of growth rate is observed as a function of square root of flow rate for the TEAB range of 20 to 60 sccm, indicating that the reaction rate is controlled by the adsorption of borane. The addition of NH3 to TEAB had the effect of lowering the deposition temperature down to 300 °C and increasing the apparent activation energy to 22 kcal/mol. Above 650 °C, the carbon concentration of the deposits increased significantly, reflecting the breakup of the amine molecule. X-ray diffraction measurements indicated the films to be in all cases amorphous. Infrared spectra of the films showed absorption peaks representing the vibrational modes of B-N, B-N-B, B-H, and N-H. The index of refraction varied between 1.76 and 2.47, depending on composition of the films. Films deposited with no NH3 above 700 °C were seen to be compressive while films below that temperature were tensile. In the range of 350 to 475 °C, the addition of NH3 to TEAB resulted in films that were mildly tensile, while below 325 °C and above 550 °C, the films were found to be compressive. Both the hardness and Young's modulus of the films decreased with higher temperatures, reflecting the influence of the carbon presence.

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