surface energies
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2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Samed Ayhan Özsoy ◽  
Safiye Meriç Acıkel ◽  
Cem Aydemir

Purpose The surface energy of the printing material can be increased to desired levels with different chemicals or methods. However, the important thing is that the surface properties of printing material are not affected negatively. In this way the aim of this paper provide that the surface properties of matte and glossy coated paper is improved by the argon containing atmospheric pressure plasma device because the plasma treatment method does not occur surface damaging on the papers. Design/methodology/approach In experimental studies, test samples cut from 160 mm × 30 mm in size from 115 g/m2 gloss- and matt-coated papers were used. The plasma treatments of paper samples were carried out with an argon containing atmospheric pressure plasma device of laboratory scale that produces plasma of the corona discharge type at radio frequency. The optimized plasma parameters were at a frequency of 20 kHz and plasma power 200 W. A copper electrode of length 12 cm and diameter 2.5 mm was placed in the centre of the nozzle. Findings Research findings showed that the surface energies of the papers increased with the increase in plasma application time. While the contact angle of the untreated glossy paper is 82.2, 8 second plasma applied G3 sample showed 54 contact angle value. Similarly, the contact angle of the base paper of matt coated is 91.1, while M3 is reduced to 60.4 contact angles by the increasing plasma time. Originality/value Plasma treatment has shown that no chemical coating is needed to increase the wettability of the paper surface by reducing the contact angle between the paper and the water droplet. In addition, the surface energies of all papers treated by argon gas containing atmospheric pressure plasma, increased. Plasma treatment provides to improve both the wettability of the paper and the adhesion property required for the ink, with an environmentally friendly approach.


Author(s):  
Wei Li ◽  
Xianghe Peng ◽  
Alfonso H W Ngan ◽  
Jaafar El-Awady

Abstract First principles calculations of the energies and relaxation of unreconstructed low-index surfaces, i.e. (001), (011) and (111) surfaces, in NiCoCr and NiFeX (X=Cu, Co or Cr) equiatomic multi-principal element alloys are presented. The calculations were conducted for twelve-layer slabs represented by special quasi-random supercells using the projector augmented wave method within the generalized gradient approximation. While experimental predictions are unavailable for comparison, the calculated surface energies agree fairly well with those from thermodynamic modeling and a bond-cutting model. In addition, the calculations unveil an important surface structure, namely, that the topmost surface layer is in contraction except for the (001) surface of NiFeCr alloy, the next layer below is in extension, and the bulk spacing is gradually recovered from the subsequent layers down. Additionally, the surface contraction is the most pronounced on the (011) plane, being about 4-10% relative to the bulk spacings. The results presented here can provide an understanding of surface-controlled phenomena such as corrosion, catalytic activities and fracture properties in these equiatomic multi-principal element alloys.


2021 ◽  
Author(s):  
◽  
Leila Rajabibonab

<p>The simulation of adsorption processes on a heterogeneous crystal surface is the main interest of this thesis. Two applications of this event have been developed with Kinetic Monte Carlo simulation. One is how to control the crystal growth by macromolecules and the other is how to measure the effective rate of interactions near a crystal surface. The first part of this thesis, considers the effective rate of catalytic conversion on a heterogeneous catalytic surface. We assume the crystal surface has two types of active site, one is neutral and the other one is highly active. We compared our result from simulation with the analytical method that is given by the homogenization theory. Our result revealed the importance of patterns of surface energies and the size of them on reaction rate.  In the second project we consider the adsorption of a homopolymer chain on a crystal surface with two types of surface energies in order to limit the growth of one site and let the other sites grow more. We developed a new Kinetic Monte Carlo simulation method in this part, which was also applied to block copolymer chains that are more complex than a homo-polymer chain. Using this method four important phases of the polymer chains at high temperatures and also the free energies of the system across different patterns of active sites have been found. We tested different types of co-polymers to find the most differentiative block copolymer for controlling the crystal growth.</p>


2021 ◽  
Author(s):  
◽  
Leila Rajabibonab

<p>The simulation of adsorption processes on a heterogeneous crystal surface is the main interest of this thesis. Two applications of this event have been developed with Kinetic Monte Carlo simulation. One is how to control the crystal growth by macromolecules and the other is how to measure the effective rate of interactions near a crystal surface. The first part of this thesis, considers the effective rate of catalytic conversion on a heterogeneous catalytic surface. We assume the crystal surface has two types of active site, one is neutral and the other one is highly active. We compared our result from simulation with the analytical method that is given by the homogenization theory. Our result revealed the importance of patterns of surface energies and the size of them on reaction rate.  In the second project we consider the adsorption of a homopolymer chain on a crystal surface with two types of surface energies in order to limit the growth of one site and let the other sites grow more. We developed a new Kinetic Monte Carlo simulation method in this part, which was also applied to block copolymer chains that are more complex than a homo-polymer chain. Using this method four important phases of the polymer chains at high temperatures and also the free energies of the system across different patterns of active sites have been found. We tested different types of co-polymers to find the most differentiative block copolymer for controlling the crystal growth.</p>


2021 ◽  
Vol 119 (20) ◽  
pp. 201603
Author(s):  
Wentao Jin ◽  
Guangde Chen ◽  
Xiangyang Duan ◽  
C. Moyses Araujo ◽  
Xubo Jia ◽  
...  
Keyword(s):  

2021 ◽  
Author(s):  
Purvika Agarwal ◽  
Debajeet K. BORA

<p><a>Here, we describe the exfoliation of 2D Hematene single layer from a Hematite nanoparticle-based nanoarchitectures obtained by a water-mediated synthesis route with the ultrasonication method in a brief period which is 5 min. The Hematene obtained shows the fine structure of honeycomb lattice resembling the Hematite hexagonal crystallographic pattern. Here, we found that the ultrasonicated Hematite film with Hematene flakes shows enhanced current density than the pristine Hematite film which can be extended further to increase the efficiency of well-performing or champion photoanode for the artificial photosynthesis application. Besides this, a new photocurrent transient spike is obtained, which we ascribed as the generation of the sub-surface state by Hematene flakes. Followed by this, we have also deciphered a qualitative predictive mechanism for the fast exfoliation of Hematene in which surface energies and hydroxylation of crystal facets are proposed to be the factor responsible for the quick exfoliation process. </a></p>


Pharmaceutics ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1434
Author(s):  
Lina Miethke ◽  
Paul Prziwara ◽  
Jan Henrik Finke ◽  
Sandra Breitung-Faes

Applying additives and excipients during the dry processing of fine particles is a common measure to control the particle–particle interactions, to specifically influence the powder properties and to enhance the process efficiency or product quality. In this study, the impacts of a particulate lubricant, a nano-disperse flow additive and liquid grinding aids on the dry fine milling and subsequent tableting of the ground material were investigated for three different organic model compounds. It is presented that the three additive classes cause varying and partly opposing effects during these process steps. Especially the lubricant and the grinding aids were shown to increase the efficiency of the milling process as well as the product fineness of the ground material, and to avoid critical product adhesions on the machine surfaces. Thereby, stable and efficient grinding conditions were partially not possible without the addition of such additives. However, as these positive effects are attributed to a reduction of the adhesive forces between the particles, much lower tablet strengths were achieved for these additives. This propagation of powder, and in turn, final product properties over whole process chains, has not been studied in detail so far. It was further revealed that the material behavior and the microstructure of the product particles is decisive for the processing as well, which is why additive effects may be product-specific and can even be suppressed under certain processing conditions. In comparison to the process performances, the powder properties and surface energies of the product particles were less influenced by the additives. On the contrary, particle-based morphologies or deformation behavior seem to play a major role in comparison to inorganic materials. Thus, it can be stated that global bulk properties and surface energies provide first indications of powder behavior and susceptibility. However, additional specific properties need to be evaluated to more clearly understand the influences of additives.


2021 ◽  
pp. 222-234
Author(s):  
David Rickard

Framboid microcrystals, which are intrinsically similar in size and habit within any individual framboid, must have all nucleated and grown at the same time. The formation of many thousands of equidimensional and equimorphic microcrystals in framboids is the fundamental evidence for burst nucleation. This is conventionally described by the LaMer model, which is characterized by (1) a lag phase before nucleation becomes significant; (2) burst nucleation where the rate of nucleation increases exponentially and may be completed in seconds; and (3) a short growth phase where nucleation becomes again insignificant. The growth phase is limited by the diffusion of Fe and S in stagnant, diffusion limited environments. By contrast, individual pyrite crystals evidence isolated nucleation and unlimited growth in advecting systems. The reaction with surface =FeS provided by sulfidized iron oxyhydroxides may a major route for producing individual pyrite crystals, rather than framboids, especially in sediments. Framboid formation by the nucleation of pyrite in solution can be described by classical nucleation theory (CNT), which leads to results consistent with observed critical supersaturation ranges, critical nucleus radius, and surface energies.


2021 ◽  
Vol 1041 ◽  
pp. 29-35
Author(s):  
Bianca Rae Pasela ◽  
Rayda P. Gammag ◽  
Acelle Pearl T. Castillo ◽  
Doebner von C. Tumacder ◽  
Kathrina Lois Taaca

In this study, facile preparation using a new solvent – lactic acid and physical properties of PAni-Cs films are observed. The main goal of the study is to easily synthesize PAni-Cs films using lactic acid as solvent through the solvent casting method and investigate if producing PAni-Cs with lactic acid will enhance its properties. The presence of PAni-Cs was confirmed by observing its structure using Fourier transform infrared (FTIR) spectroscopy. The wettability of the films showed that films produced with lactic acid are less hydrophobic than those produced with acetic acid. Consequently, the computed surface energies revealed PAni-Cs films produced using lactic acid were higher. Water uptake of the films showed deviations when PAni and the solvents (lactic acid and acetic acid) were introduced. Furthermore, films produced with lactic acid were observed to be more flexible. These characterizations revealed that PAni-Cs produced with lactic acid are comparable to the properties of those produced with acetic acid showing that lactic acid helps in the improvement of PAni-Cs surface properties.


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