scholarly journals Revisiting the Surface Energy Imbalance

2021 ◽  
Author(s):  
Jielun Sun ◽  
William J. Massman ◽  
Robert M. Banta ◽  
Sean P. Burns
Keyword(s):  
Surface Energy ◽  
Energy Imbalance

Reflections on the surface energy imbalance problem

2012 ◽  
Vol 156 ◽  
pp. 65-74 ◽  
Author(s):  
Ray Leuning ◽  
Eva van Gorsel ◽  
William J. Massman ◽  
Peter R. Isaac
Keyword(s):  
Surface Energy ◽  
Energy Imbalance ◽  
Imbalance Problem

Impact of Climate Change and Surface Energy (Im) Balance on North-East India Monsoonal Rainfall

2021 ◽  
Vol 7 (2) ◽  
pp. 35-47
Author(s):  
Pramod Kumar
Keyword(s):  
Climate Change ◽  
Surface Energy ◽  
Thermal Radiation ◽  
Sensible Heat ◽  
Study Region ◽  
Near Surface ◽  
Energy Imbalance ◽  
North East India ◽  
North East ◽  
Monsoonal Precipitation

In recent decades, climate change and its impact on the ecosystem has remained a concern from global to regional to local scale. Many studies performed over India have highlighted the change in precipitation associated with the Indian summer monsoon (ISM) and its linkage with changed land surface processes. Over North-East India (NEI), changed surface and atmospheric energy imbalance due to increase in wasteland, deforestation and over cultivation have made the soil barren. In addition, soil moisture of barren land has decreased, latent (sensible) heat decreased (increased) with stimulating ground heat increment. This led to lower evapotranspiration and convection leading to precipitation decrement. To analyse this in detail, the present study shows a lower increase in the near surface temperature during 1956-1985 (period I), but a higher increasing trend has been seen during 1986-2015 (period II). In the case of precipitation trends, an increase during period I and a decrease at a 95% significant level during period II are seen. The average air temperature warming rate increase of 0.09 °C/year is observed. The monsoonal precipitation has decreased significantly in recent years (1986-2015) than that in the past (1956-1985). In addition, a decrease in monsoonal precipitation at 0.35 mm/year rate during period II is seen over NEI. A prominent increment of 0.12 W/m2 is observed in surface sensible heat flux over NEI. Land use land cover change (LULCC) is continuously altering the local rate of change of thermal radiation, evapotranspiration and convection, and has also played a critical role in defining monsoonal precipitation over NEI. However, the surface net solar and thermal radiation change are in equilibrium with the surface sensible and latent heat for sustaining the surface energy budget. Hence, a small change in surface net radiation causes an imbalance of surface energetics. It is one of the most prominent causes for the precipitation pattern changes over NEI. The LULCCs and earth’ surface energy imbalance reinforce climate variability and climate change over the study region.

The annealed (0001) α-alumina surface and its influence on thin-film growth

1995 ◽  
Vol 53 ◽  
pp. 336-337
Author(s):  
Michael W. Bench ◽  
Paul G. Kotula ◽  
C. Barry Carter
Keyword(s):  
Electron Microscopy ◽  
Surface Energy ◽  
Film Growth ◽  
Thin Film Growth ◽  
Energy Calculations ◽  
Transmission Electron ◽  
Reflection Electron Microscopy ◽  
Low Energy Electron ◽  
Surface Nature

The growth of semiconductors, superconductors, metals, and other insulators has been investigated using alumina substrates in a variety of orientations. The surface state of the alumina (for example surface reconstruction and step nature) can be expected to affect the growth nature and quality of the epilayers. As such, the surface nature has been studied using a number of techniques including low energy electron diffraction (LEED), reflection electron microscopy (REM), transmission electron microscopy (TEM), molecular dynamics computer simulations, and also by theoretical surface energy calculations. In the (0001) orientation, the bulk alumina lattice can be thought of as a layered structure with A1-A1-O stacking. This gives three possible terminations of the bulk alumina lattice, with theoretical surface energy calculations suggesting that termination should occur between the Al layers. Thus, the lattice often has been described as being made up of layers of (Al-O-Al) unit stacking sequences. There is a 180° rotation in the surface symmetry of successive layers and a total of six layers are required to form the alumina unit cell.

The nucleation of cavities at grain boundaries

1987 ◽  
Vol 45 ◽  
pp. 288-291
Author(s):  
P. J. Goodhew
Keyword(s):  
Surface Tension ◽  
Surface Energy ◽  
Grain Boundaries ◽  
Radiation Damage ◽  
Impurity Concentration ◽  
Driving Force ◽  
Nucleation And Growth ◽  
Phase Boundaries ◽  
Cavity Nucleation ◽  
Spherical Bubble

Cavity nucleation and growth at grain and phase boundaries is of concern because it can lead to failure during creep and can lead to embrittlement as a result of radiation damage. Two major types of cavity are usually distinguished: The term bubble is applied to a cavity which contains gas at a pressure which is at least sufficient to support the surface tension (2g/r for a spherical bubble of radius r and surface energy g). The term void is generally applied to any cavity which contains less gas than this, but is not necessarily empty of gas. A void would therefore tend to shrink in the absence of any imposed driving force for growth, whereas a bubble would be stable or would tend to grow. It is widely considered that cavity nucleation always requires the presence of one or more gas atoms. However since it is extremely difficult to prepare experimental materials with a gas impurity concentration lower than their eventual cavity concentration there is little to be gained by debating this point.

Influence of Fiber Surface Energy on Mechanical Properties of Sisal Fiber - Bio Based Epoxy Composites

2019 ◽  
Vol 35 (4) ◽  
pp. 485-496
Author(s):  
S. RAJKUMAR ◽  
◽  
R. JOSEPH BENSINGH ◽  
M. ABDUL KADER ◽  
SANJAY K NAYAK ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Energy ◽  
Fiber Surface ◽  
Epoxy Composites ◽  
Sisal Fiber

Surface energy of cellulosic materials: The effect of particle morphology, particle size, and hydroxyl number

TAPPI Journal ◽  
2015 ◽  
Vol 14 (9) ◽  
pp. 565-576 ◽  
Author(s):  
YUCHENG PENG ◽  
DOUGLAS J. GARDNER
Keyword(s):  
Particle Size ◽  
Surface Energy ◽  
Particle Morphology ◽  
Nanofibrillated Cellulose ◽  
Particle Sizes ◽  
Hydroxyl Number ◽  
Small Individual ◽  
Dispersion Component ◽  
Commercial Applications ◽  
Lower Temperature

Understanding the surface properties of cellulose materials is important for proper commercial applications. The effect of particle size, particle morphology, and hydroxyl number on the surface energy of three microcrystalline cellulose (MCC) preparations and one nanofibrillated cellulose (NFC) preparation were investigated using inverse gas chromatography at column temperatures ranging from 30ºC to 60ºC. The mean particle sizes for the three MCC samples and the NFC sample were 120.1, 62.3, 13.9, and 9.3 μm. The corresponding dispersion components of surface energy at 30°C were 55.7 ± 0.1, 59.7 ± 1.3, 71.7 ± 1.0, and 57.4 ± 0.3 mJ/m2. MCC samples are agglomerates of small individual cellulose particles. The different particle sizes and morphologies of the three MCC samples resulted in various hydroxyl numbers, which in turn affected their dispersion component of surface energy. Cellulose samples exhibiting a higher hydroxyl number have a higher dispersion component of surface energy. The dispersion component of surface energy of all the cellulose samples decreased linearly with increasing temperature. MCC samples with larger agglomerates had a lower temperature coefficient of dispersion component of surface energy.

A new method for quantifying the blocking of coated paperboard

TAPPI Journal ◽  
2010 ◽  
Vol 9 (5) ◽  
pp. 29-35 ◽  
Author(s):  
PAULINE SKILLINGTON ◽  
YOLANDE R. SCHOEMAN ◽  
VALESKA CLOETE ◽  
PATRICE C. HARTMANN
Keyword(s):  
Surface Roughness ◽  
Fatty Acid ◽  
Surface Energy ◽  
Film Thickness ◽  
External Factors ◽  
Additive Concentration ◽  
Pressure Surface ◽  
Fatty Acid Amides ◽  
Coated Surfaces ◽  
Definite Period

Blocking is undesired adhesion between two surfaces when subjected to pressure and temperature constraints. Blocking between two coated paperboards in contact with each other may be caused by inter-diffusion, adsorption, or electrostatic forces occurring between the respective coating surfaces. These interactions are influenced by factors such as the temperature, pressure, surface roughness, and surface energy. Blocking potentially can be reduced by adjusting these factors, or by using antiblocking additives such as talc, amorphous silica, fatty acid amides, or polymeric waxes. We developed a method of quantifying blocking using a rheometer. Coated surfaces were put in contact with each other with controlled pressure and temperature for a definite period. We then measured the work necessary to pull the two surfaces apart. This was a reproducible way to accurately quantify blocking. The method was applied to determine the effect external factors have on the blocking tendency of coated paperboards, i.e., antiblocking additive concentration, film thickness, temperature, and humidity.

Effect of Plasma Surface Treatment on Surface Energy and Adhesion Properties for Cr Coating on Substrates

2013 ◽  
Vol 51 (10) ◽  
pp. 735-741
Author(s):  
Dong-Yong Kim ◽  
Eun-Wook Jeong ◽  
Kwun Nam Hui ◽  
Youngson Choe ◽  
Jung-Ho Han ◽  
...  
Keyword(s):  
Surface Energy ◽  
Surface Treatment ◽  
Adhesion Properties ◽  
Plasma Surface ◽  
Plasma Surface Treatment ◽  
Cr Coating
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