Investigating the Wettability of Rapeseed Leaves

2021 ◽  
Vol 37 (3) ◽  
pp. 399-409
Author(s):  
Yong He ◽  
Jianjian Wu ◽  
Shupei Xiao ◽  
Hui Fang ◽  
Qishuai Zheng
Keyword(s):  
Surface Tension ◽  
Free Energy ◽  
Significant Influence ◽  
Leaf Surface ◽  
Contact Angles ◽  
List Type ◽  
Factors Affecting ◽  
Spray Droplets ◽  
Droplet Sizes ◽  
Leaf Wettability

HighlightsContact angles of spray droplets were positively correlated with their surface tension.Wettability of rape leaves was generally poor for most pesticides.Surface structure and free energy determine the hydrophobicity of rape leaves.The size of the spray droplets had no significant influence on rape leaf wettability.Abstract. In order to improve the deposition and adherence of spray droplets on leaf surfaces, the wettability of rapeseed leaves was investigated. We explored the effect of different pesticides and test surfaces on droplet contact angles, and analyzed the effects of leaf surface properties, droplet sizes and the addition of organosilicone adjuvant on wettability. The results indicated that contact angles of different liquids were positively correlated with their surface tension for rapeseed leaves. The wettability of rapeseed leaves was generally poor using different pesticides, but was highest for a fungicide mixture of difenoconazole and propiconazole. The hydrophobicity of rapeseed leaves is largely determined by the complex microstructure and the low surface free energy of the leaves. The size of the spray droplets had no significant influence on the wettability. Moreover, the addition of an organosilicone adjuvant significantly reduced the surface tension of all spray droplets, with the best result for a 50% procymidone solution. In conclusion, the factors affecting rapeseed leaf surface wettability should be considered comprehensively before selecting the appropriate pesticide, so as to improve its utilization rates. Keywords: Contact angle, Leaf surface, Pesticide application, Spray droplet.

Retention and Spread Capability of Impacted Droplets with Surfactant and Hydrocolloid Based Adjuvants

2021 ◽  
Vol 64 (6) ◽  
pp. 1883-1894
Author(s):  
JohnPaul R. Abbott ◽  
Heping Zhu ◽  
Hongyoung Jeon
Keyword(s):  
Surface Tension ◽  
High Speed ◽  
Leaf Surface ◽  
Imaging System ◽  
Ionic Surfactant ◽  
List Type ◽  
Cross Sectional ◽  
Spray Solution ◽  
Leaf Surfaces ◽  
Leaf Wettability

HighlightsRetention and spread of droplets with seven adjuvants were investigated on flat leaves.Surface tension of spray solutions, leaf wettability, and roughness strongly affected droplet retention and spread.Complete droplet retention occurred on hydrophilic leaves with all adjuvants and concentrations.High retention and spread on superhydrophobic leaves were achieved with the organo-silicone adjuvant.No retention occurred on superhydrophobic leaf surfaces with the hydrocolloid polymer adjuvant.Abstract. To optimize spray application efficiency, it is necessary to understand how the addition of adjuvants modifies the deposition properties of spray droplets on leaf surfaces due to variations in adhesive characteristics, such as roughness and wettability. Retention and spread of droplets with seven commercially available adjuvants were tested and compared at different concentrations. Tests were conducted with three leaf surfaces ranging in roughness and wettability from very smooth and hydrophilic to very rough and superhydrophobic. The adjuvants were formulated with non-ionic surfactant, crop oil, seed oil, organo-silicone, hydrocolloid polymer, or combinations of these agents as primary ingredients. Droplets of approximately 340 µm diameter were emitted from a streamed mono-sized generator. Droplet impact and spread were recorded with a 3D imaging system consisting of three high-speed digital cameras and analyzed using 3D motion analysis software. Retention and spread were determined by comparing droplet liquid volumes and droplet cross-sectional areas before and after impact, respectively. The surface tension of spray solutions and wettability of leaf surfaces strongly affected droplet retention. Droplets with lower surface tension were more likely to achieve high retention than those with higher surface tension. Droplet retention generally decreased with increasing leaf roughness-wettability. All droplets with and without adjuvants achieved 100% retention on the hydrophilic leaf surface. Addition of non-ionic, oil, or organo-silicone based adjuvants in the spray solution improved droplet retention on hydrophobic leaves, while the organo-silicone based adjuvant achieved the highest retention on superhydrophobic leaf surfaces. Droplet retention with the hydrocolloid polymer adjuvant was generally comparable to the other six adjuvants on the hydrophilic leaves and on the hydrophobic leaves with intermediate roughness and wettability but failed to achieve any retention on the superhydrophobic leaves. To improve droplet retention and adhesion, selection of adjuvants representing the non-ionic, oil, organo-silicone, blended, or hydrocolloid-based additives for enhancing spray solution performance must comply with the leaf surface characteristics. Keywords: Droplet rebound, High-speed imaging, Leaf wettability, Pesticide droplet deposition, Topography parameters.

Design Parameters for Superhydrophobicity and Superoleophobicity

MRS Bulletin ◽  
2008 ◽  
Vol 33 (8) ◽  
pp. 752-758 ◽  
Author(s):  
Anish Tuteja ◽  
Wonjae Choi ◽  
Gareth H. McKinley ◽  
Robert E. Cohen ◽  
Michael F. Rubner
Keyword(s):  
Surface Tension ◽  
Surface Topography ◽  
Leaf Surface ◽  
Contact Angles ◽  
Design Parameters ◽  
Lotus Leaf ◽  
General Design ◽  
Composite Interface

AbstractRecent experiments have revealed that the wax on the lotus leaf surface, by itself, is weakly hydrophilic, even though the lotus leaf is known to be superhydrophobic. Conventional understanding suggests that a surface of such waxy composition should not be able to support superhydrophobicity and high contact angles between a liquid and the surface. Here, we show that the unexpected superhydrophobicity is related to the presence of “reentrant texture” (that is, a multivalued surface topography) on the surface of the lotus leaf. We exploit this understanding to enable the development of superoleophobic surfaces (i.e., surfaces that repel extremely low-surface-tension liquids, such as various alkanes), where essentially no naturally oleophobic materials exist. We also develop general design parameters that enable the evaluation of the robustness of the composite interface on a particular surface. Based on these design parameters, we also rank various superhydrophobic and superoleophobic substrates discussed in the literature, with particular emphasis on surfaces developed from inherently hydrophilic or oleophilic materials.

scholarly journals Influence of the ambient temperature on water and diiodomethane contact angle with quartz surface

2015 ◽  
Vol 70 (1) ◽  
Author(s):  
Konrad Terpiłowski
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Free Energy ◽  
Ambient Temperature ◽  
Everyday Life ◽  
Temperature Change ◽  
Contact Angles ◽  
Quartz Surface ◽  
Show Difference ◽  
Increasing Temperature

AbstractWettability of solids is a key phenomenon in many processes. One should mentioned those which accompany us in our everyday life i.e. washing or cementing as well as those applied in industry e.g. flotation of minerals. Value of the contact angles are affected by many factors. One of them is temperature. In this paper monocrystaline quartz was used in the investigations which were carried out in the range 5−50°C with the step every 5°C. As follows the value of the contact angle of both water and diiodomethane changes with the increasing temperature. The change of its value for water is much larger than in case of another liquids of apolar character. Using Chibowski approach the apparent surface free energy was calculated in two ways with and without correction about temperature change of the surface tension. The calculation show difference between both results. Taking into consideration another value of the surface tension should not be neglected even if measurements is taken at a temperature close to 20°C which is the standard in one in such measurements

scholarly journals Magnetic Field Effect on Water Surface Tension in Aspect of Glass and Mica Wettability

2020 ◽  
Vol 4 (3) ◽  
pp. 37
Author(s):  
Aleksandra Szcześ ◽  
Emil Chibowski ◽  
Emilia Rzeźnik
Keyword(s):  
Magnetic Field ◽  
Surface Tension ◽  
Free Energy ◽  
Surface Free Energy ◽  
Magnetic Field Effect ◽  
Contact Angles ◽  
Acid Base ◽  
Water Contact ◽  
The Difference ◽  
The Magnetic Field

It was reported in many papers that the magnetic field (MF) affects properties of water, and, among others, its surface tension. Thus, it should be reflected in changes of the wetting contact angle of a water droplet deposited on the solid surface. In this study, the water contact angles were measured on the glass and mica surface. The water was first exposed to the static magnetic field (MF) (15 mT or 0.27 T) for 1, 5, and 10 min under dynamic conditions. Then applying the van Oss et al. approach (LWAB), it was found that the MF effect is reflected in the changes of the calculated acid-base components of the solids, especially the electron donor parameter. However, the total surface free energy of the solids remained practically unchanged. Moreover, the apparent surface free energy of the solids calculated from the water contact angle hysteresis (CAH), i.e., the difference between the advancing and receding contact angles, changes in the same way as the electron donor parameter does. Since the solid surfaces were not magnetically treated, the acid-base components, which are mainly results from hydrogen bonding interactions, may be indirect evidence of the water structure changed by the MF action. All of the mentioned changes are greater for the glass than for a more hydrophilic mica surface and depend upon the time of MF exposure and its strength. The magnetic field effect on the changes of the surface-free energy parameters for the mica and glass is opposite what may be due to the difference in the surface hydrophilicity. A “magnetic memory” effect was also found. The effect of MF on the water surface tension depends on the circulation time. It increases with the field duration. Moreover, the changes in the work of water adhesion indicate the possibility of solid surface wettability changes by the external MF water treatment. However, these are preliminary results that need further confirmation by other techniques.

Factors Affecting the Use and Consequences of Management Accounting Practices in A Transitional Economy: The Case of Vietnam

2016 ◽  
pp. 54-73 ◽  
Author(s):  
Anh Doan Ngoc Phi
Keyword(s):  
Significant Influence ◽  
Quantitative Data ◽  
Structural Equation ◽  
Qualitative Data ◽  
Management Accounting ◽  
Transitional Economy ◽  
Equation Modeling ◽  
Enterprise Performance ◽  
Factors Affecting

This study seeks to help fill an important gap in the literature by investigating factors that have facilitated the use of management accounting practices (MAPs) in Vietnam - a transitional economy. Data were collected from 220 medium-to-large enterprises. Follow-up interviews were conducted with 20 accounting heads/vice heads to obtain further information and clarification. The quantitative data collected was analyzed using both descriptive and inferential statistics (including t-tests and structural equation modeling), while the qualitative data was used to shed further light on the various relationships described by the quantitative analysis. This paper reveals that both decentralization and competition have a positive, significant influence on the use of new MAPs except for the old ones. Consequently, the use of MAPs has a positive, significant influence on enterprise performance.

Bifunctional Composites for Biofilms Modulation on Cervical Restorations

2021 ◽  
pp. 002203452110181
Author(s):  
A.A. Balhaddad ◽  
I.M. Garcia ◽  
L. Mokeem ◽  
M.S. Ibrahim ◽  
F.M. Collares ◽  
...  
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Contact Angles ◽  
Bacterial Biofilm ◽  
Dental Composite ◽  
Log P ◽  
Rrna Gene ◽  
Cervical Lesions ◽  
Biofilm Growth ◽  
Biofilm Development

Cervical composites treating root carious and noncarious cervical lesions usually extend subgingivally. The subgingival margins of composites present poor plaque control, enhanced biofilm accumulation, and cause gingival irritation. A potential material to restore such lesions should combine agents that interfere with bacterial biofilm development and respond to acidic conditions. Here, we explore the use of new bioresponsive bifunctional dental composites against mature microcosm biofilms derived from subgingival plaque samples. The designed formulations contain 2 bioactive agents: dimethylaminohexadecyl methacrylate (DMAHDM) at 3 to 5 wt.% and 20 wt.% nanosized amorphous calcium phosphate (NACP) in a base resin. Composites with no DMAHDM and NACP were used as controls. The newly formulated 5% DMAHDM–20% NACP composite was analyzed by micro-Raman spectroscopy and transmission electron microscopy. The wettability and surface-free energy were also assessed. The inhibitory effect on the in vitro biofilm growth and the 16S rRNA gene sequencing of survival bacterial colonies derived from the composites were analyzed. Whole-biofilm metabolic activity, polysaccharide production, and live/dead images of the biofilm grown over the composites complement the microbiological assays. Overall, the designed formulations had higher contact angles with water and lower surface-free energy compared to the commercial control. The DMAHDM-NACP composites significantly inhibited the growth of total microorganisms, Porphyromonas gingivalis, Prevotella intermedia/nigrescens, Aggregatibacter actinomycetemcomitans, and Fusobacterium nucleatum by 3 to 5-log ( P < 0.001). For the colony isolates from control composites, the composition was typically dominated by the genera Veillonella, Fusobacterium, Streptococcus, Eikenella, and Leptotrichia, while Fusobacterium and Veillonella dominated the 5% DMAHDM–20% NACP composites. The DMAHDM-NACP composites contributed to over 80% of reduction in metabolic and polysaccharide activity. The suppression effect on plaque biofilms suggested that DMAHDM-NACP composites might be used as a bioactive material for cervical restorations. These results may propose an exciting path to prevent biofilm growth and improve dental composite restorations’ life span.

scholarly journals Influence of moisture content on the contact angle and surface tension measured on birch wood surfaces

2021 ◽  
Author(s):  
Rami Benkreif ◽  
Fatima Zohra Brahmia ◽  
Csilla Csiha
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Moisture Content ◽  
Solid Wood ◽  
Contact Angles ◽  
Surface Moisture ◽  
Wood Coatings ◽  
The Relationship ◽  
Wood Surfaces

AbstractSurface tension of solid wood surfaces affects the wettability and thus the adhesion of various adhesives and wood coatings. By measuring the contact angle of the wood, the surface tension can be calculated based on the Young-Dupré equation. Several publications have reported on contact angle measured with different test liquids, under different conditions. Results can only be compared if the test conditions are similar. While the roles of the drop volume, image shooting time etc., are widely recognized, the role of the wood surface moisture content (MC) is not evaluated in detail. In this study, the effect of wood moisture content on contact angle values, measured with distilled water and diiodomethane, on sanded birch (Betula pendula) surfaces was investigated, in order to find the relationship between them. With increasing MC from approximately 6% to 30%, increasing contact angle (decreasing surface tension) values were measured according to a logarithmic function. The function makes possible the calculation of contact angles that correspond to different MCs.

scholarly journals On factors affecting surface free energy of carbon black for reinforcing rubber

2020 ◽  
Vol 9 (1) ◽  
pp. 170-181 ◽  
Author(s):  
Shangyong Zhang ◽  
Ruipeng Zhong ◽  
Ruoyu Hong ◽  
David Hui
Keyword(s):  
Free Energy ◽  
Carbon Black ◽  
Surface Free Energy ◽  
Surface Activity ◽  
Gas Flow ◽  
Influential Factors ◽  
Chromatographic Column ◽  
Factors Affecting ◽  
Carrier Gas Flow

AbstractThe surface activity of carbon black (CB) is an important factor affecting the reinforcement of rubber. The quantitative determination of the surface activity (surface free energy) of CB is of great significance. A simplified formula is obtained to determine the free energy of CB surface through theoretical analysis and mathematical derivation. The surface free energy for four kinds of industrial CBs were measured by inverse gas chromatography, and the influential factors were studied. The results showed that the aging time of the chromatographic column plays an important role in accurate measurement of the surface free energy of CB, in comparison with the influences from the inlet pressure and carrier gas flow rate of the chromatographic column filled with CB. Several kinds of industrial CB were treated at high temperature, and the surface free energy of CB had a significant increase. With the increase of surface free energy, the maximum torque was decreased significantly, the elongation at break tended to increase, the heat generation of vulcanizates was increased, and the wear resistance was decreased.

Liquid Film Migration in Aluminium Brazing Sheet?

2006 ◽  
Vol 519-521 ◽  
pp. 1151-1156 ◽  
Author(s):  
A. Wittebrood ◽  
S. Desikan ◽  
R. Boom ◽  
Laurens Katgerman
Keyword(s):  
Free Energy ◽  
Corrosion Resistance ◽  
Liquid Film ◽  
Significant Influence ◽  
Clear Explanation ◽  
Distribution Of Elements ◽  
Essential Properties ◽  
Low Levels ◽  
Number Of Publications ◽  
Liquid Film Migration

From literature and own observations it is known that the clad and core alloys that make up aluminium brazing sheet can show severe interaction during the brazing cycle. This interaction leads to a complete re-distribution of elements, changing essential properties like strength and corrosion resistance. This interaction has been reported many times but up to present time no clear explanation is given why this interaction is actually occurring. There are a number of publications addressing the circumstances under which the interaction is more severe. Chemistry and low levels of strain applied before brazing have a significant influence on the severity of the interaction. As a yet possible mechanism behind the interaction Liquid Film Migration is mentioned. The observations done so far are in line with this described mechanism but no ultimate proof has been given so far. The question why the interaction takes place cannot be answered yet, clearly a change of free energy of the system is involved but the mechanism or mechanisms behind the change is unclear.

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