scholarly journals Capillary Pumping between Droplets on Superhydrophobic Surfaces

2021 ◽  
Author(s):  
shiva moradi ◽  
Mohammad Charsooghi ◽  
Luca Businaro ◽  
Mehdi Habibi ◽  
Ali-Reza Moradi
Keyword(s):  
Image Processing ◽  
Surface Tension ◽  
Morphometric Parameters ◽  
The Other ◽  
Superhydrophobic Surfaces ◽  
Curvature Radius ◽  
Capillary Channel ◽  
Droplet Sizes ◽  
Balloon Experiment ◽  
Spherical Droplets

The famous two-balloon experiment involves two identical balloons filled up with air and connected via a hollow tube, and upon onsetting the experiment one of the balloons shrinks and the other expands. Here, we present the liquid version of that experiment. We use superhydrophobic (SHP) substrates to form spherical droplets and connect them with a capillary channel. Different droplet sizes, substrates of different hydrophobicities, and various channel pathways are investigated, and morphometric parameters of the droplets are measured through image processing. In the case of SHP substrates the pumping is from the smaller droplet to the larger one, similar to the two-balloon experiment. However, if one or both of the droplets are positioned on a normal substrate the curvature radius will indicate the direction of pumping. We interpret the results by considering the Laplace pressures and the surface tension applied by the channel at the connecting points.

Immunoferritin localization of intracellular antigens in positively stained frozen sections

1978 ◽  
Vol 36 (2) ◽  
pp. 168-169
Author(s):  
K. T. Tokuyasu
Keyword(s):  
Surface Tension ◽  
Water Surface ◽  
Thin Layers ◽  
The Other ◽  
Positive Staining ◽  
Frozen Sections ◽  
The Past ◽  
Ultrathin Frozen Sections ◽  
Definition Of

During the past investigations of immunoferritin localization of intracellular antigens in ultrathin frozen sections, we found that the degree of negative staining required to delineate u1trastructural details was often too dense for the recognition of ferritin particles. The quality of positive staining of ultrathin frozen sections, on the other hand, has generally been far inferior to that attainable in conventional plastic embedded sections, particularly in the definition of membranes. As we discussed before, a main cause of this difficulty seemed to be the vulnerability of frozen sections to the damaging effects of air-water surface tension at the time of drying of the sections.Indeed, we found that the quality of positive staining is greatly improved when positively stained frozen sections are protected against the effects of surface tension by embedding them in thin layers of mechanically stable materials at the time of drying (unpublished).

Computer Vision and robotics in postal automation

1999 ◽  
Vol 18 (3-4) ◽  
pp. 265-273
Author(s):  
Giovanni B. Garibotto
Keyword(s):  
Image Processing ◽  
Computer Vision ◽  
Pattern Recognition ◽  
Material Handling ◽  
State Of The Art ◽  
Short Description ◽  
The Other ◽  
Functional Requirements ◽  
Postal Automation ◽  
And Robotics

The paper is intended to provide an overview of advanced robotic technologies within the context of Postal Automation services. The main functional requirements of the application are briefly referred, as well as the state of the art and new emerging solutions. Image Processing and Pattern Recognition have always played a fundamental role in Address Interpretation and Mail sorting and the new challenging objective is now off-line handwritten cursive recognition, in order to be able to handle all kind of addresses in a uniform way. On the other hand, advanced electromechanical and robotic solutions are extremely important to solve the problems of mail storage, transportation and distribution, as well as for material handling and logistics. Finally a short description of new services of Postal Automation is referred, by considering new emerging services of hybrid mail and paper to electronic conversion.

scholarly journals Analysis of the Nosema Cells Identification for Microscopic Images

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3068
Author(s):  
Soumaya Dghim ◽  
Carlos M. Travieso-González ◽  
Radim Burget
Keyword(s):  
Neural Network ◽  
Machine Learning ◽  
Image Processing ◽  
Deep Learning ◽  
The Other ◽  
Support Vector ◽  
Learning Approaches ◽  
Microscopic Images ◽  
Trained Neural Network ◽  
Nosema Disease

The use of image processing tools, machine learning, and deep learning approaches has become very useful and robust in recent years. This paper introduces the detection of the Nosema disease, which is considered to be one of the most economically significant diseases today. This work shows a solution for recognizing and identifying Nosema cells between the other existing objects in the microscopic image. Two main strategies are examined. The first strategy uses image processing tools to extract the most valuable information and features from the dataset of microscopic images. Then, machine learning methods are applied, such as a neural network (ANN) and support vector machine (SVM) for detecting and classifying the Nosema disease cells. The second strategy explores deep learning and transfers learning. Several approaches were examined, including a convolutional neural network (CNN) classifier and several methods of transfer learning (AlexNet, VGG-16 and VGG-19), which were fine-tuned and applied to the object sub-images in order to identify the Nosema images from the other object images. The best accuracy was reached by the VGG-16 pre-trained neural network with 96.25%.

A note on the instabilities of a horizontal shear flow with a free surface

2000 ◽  
Vol 406 ◽  
pp. 337-346 ◽  
Author(s):  
L. ENGEVIK
Keyword(s):  
Surface Tension ◽  
Free Surface ◽  
Shear Flow ◽  
Velocity Profile ◽  
Froude Number ◽  
The Other ◽  
Algebraic Equations ◽  
Horizontal Shear ◽  
Analytical Treatment ◽  
Unstable Region

The instabilities of a free surface shear flow are considered, with special emphasis on the shear flow with the velocity profile U* = U*0sech2 (by*). This velocity profile, which is found to model very well the shear flow in the wake of a hydrofoil, has been focused on in previous studies, for instance by Dimas & Triantyfallou who made a purely numerical investigation of this problem, and by Longuet-Higgins who simplified the problem by approximating the velocity profile with a piecewise-linear profile to make it amenable to an analytical treatment. However, none has so far recognized that this problem in fact has a very simple solution which can be found analytically; that is, the stability boundaries, i.e. the boundaries between the stable and the unstable regions in the wavenumber (k)–Froude number (F)-plane, are given by simple algebraic equations in k and F. This applies also when surface tension is included. With no surface tension present there exist two distinct regimes of unstable waves for all values of the Froude number F > 0. If 0 < F [Lt ] 1, then one of the regimes is given by 0 < k < (1 − F2/6), the other by F−2 < k < 9F−2, which is a very extended region on the k-axis. When F [Gt ] 1 there is one small unstable region close to k = 0, i.e. 0 < k < 9/(4F2), the other unstable region being (3/2)1/2F−1 < k < 2 + 27/(8F2). When surface tension is included there may be one, two or even three distinct regimes of unstable modes depending on the value of the Froude number. For small F there is only one instability region, for intermediate values of F there are two regimes of unstable modes, and when F is large enough there are three distinct instability regions.

scholarly journals Unsteady flow induced by a withdrawal point beneath a free surface

2005 ◽  
Vol 47 (2) ◽  
pp. 185-202 ◽  
Author(s):  
T. E. Stokes ◽  
G. C. Hocking ◽  
L. K. Forbes
Keyword(s):  
Surface Tension ◽  
Free Surface ◽  
Unsteady Flow ◽  
Critical Values ◽  
The Other ◽  
Withdrawal Rate ◽  
Steady Solutions

AbstractThe unsteady axisymmetric withdrawal from a fluid with a free surface through a point sink is considered. Results both with and without surface tension are included and placed in context with previous work. The results indicate that there are two critical values of withdrawal rate at which the surface is drawn directly into the outlet, one after flow initiation and the other after the flow has been established. It is shown that the larger of these values corresponds to the point at which steady solutions no longer exist.

Comparison of Four Surfactants: In Vitro Surface Properties and Responses of Preterm Lambs to Treatment at Birth

PEDIATRICS ◽  
1987 ◽  
Vol 79 (1) ◽  
pp. 38-46
Author(s):  
Machiko Ikegami ◽  
Yotaro Agata ◽  
Tarek Elkady ◽  
Mikko Hallman ◽  
David Berry ◽  
...  
Keyword(s):  
Surface Tension ◽  
Surface Properties ◽  
Surface Adsorption ◽  
Soluble Proteins ◽  
The Other ◽  
Clinical Responses ◽  
Spreading Rates ◽  
Surface Spreading

Natural sheep surfactant, rabbit surfactant, human surfactant, and surfactant TA were compared for in vitro surface properties and for responses of preterm lambs to treatment. Equivalent amounts of sheep, rabbit, and human surfactants were needed to lower the surface tension to less than 10 dynes/cm, whereas four times less surfactant TA similarly lowered the surface tension. Surface-spreading rates were similar for the surfactants. The surface adsorption of the batch of human surfactant tested was much slower than was adsorption of the other surfactants. Ventilation was significantly improved in all surfactant-treated lambs relative to the control lambs, indicating the general efficacy of the surfactant treatments. Overall, surfactant TA had the best in vitro characteristics, yet the preterm lambs treated at birth with surfactant TA had lower Po2 values and higher ventilatory requirements than did the sheep surfactant-treated lambs. The in vivo responses to rabbit surfactant were intermediate between the responses to sheep surfactant and to surfactant TA. Human surfactant resulted in the least effective clinical response. More of the phosphatidylcholine associated with human surfactant and surfactant TA was lost from the alveoli and lung tissue after four hours of ventilation than was lost from sheep or rabbit surfactant-treated lambs. More intravascular radiolabeled albumin leaked into the alveoli of the surfactant TA-treated lambs than sheep or rabbit surfactant-treated. lambs. The four surfactants also had different sensitivities to the effects on minimum surface tensions of the soluble proteins present in alveolar washes. The study demonstrates that the range of clinical responses was not predictable based on the in vitro surface properties that we measured. The surfactants behaved differently with respect to loss from the lungs and sensitivity to soluble proteins. Factors other than surface properties are important for the in vivo responses to surfactant treatments.

Soft-Computing-Based Approaches for Plant Leaf Disease Detection

2019 ◽  
pp. 100-113
Author(s):  
Vivek K. Verma ◽  
Tarun Jain
Keyword(s):  
Image Processing ◽  
Leaf Area ◽  
Soft Computing ◽  
Environmental Conditions ◽  
The Other ◽  
Disease Detection ◽  
Plant Leaves ◽  
Plant Leaf ◽  
Disease Occurrence ◽  
Plant Image

The disease occurrence phenomena in plants are season-based which is dependent on the presence of the pathogen, crops, environmental conditions, and varieties grown. Some plant varieties are particularly subject to outbreaks of diseases; on the other hand, some are opposite to them. Huge numbers of diseases are seen on the plant leaves and stems. Diseases management is a challenging task. Generally, diseases are seen on the leaves or stems of the plant. Image processing is the best way for the detection of plant leaf diseases. Different kinds of diseases occur because of the attack of bacteria, fungi, and viruses. The monitoring of leaf area is an important tool in studying physiological capabilities associated with plant boom. Plant disorder is usually an unusual growth or dysfunction of a plant. Sometimes diseases damage the leaves of plants.

scholarly journals Jetting Performance of Polyethylene Glycol and Reactive Dye Solutions

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 739 ◽  
Author(s):  
Zhiyuan Tang ◽  
Kuanjun Fang ◽  
Yawei Song ◽  
Fuyun Sun
Keyword(s):  
Surface Tension ◽  
Polyethylene Glycol ◽  
Production Efficiency ◽  
Hydrophobic Interactions ◽  
Reactive Dye ◽  
Droplet Formation ◽  
Visible Absorption ◽  
Fluid Behavior ◽  
Spherical Droplets ◽  
Dye Solutions

The jetting performance of dye inks determines the image quality, production efficiency, and lifetime of the print head. In the present study, we explored the jetting performance of mixed solutions of polyethylene glycol (PEG) and reactive dye by testing the visible absorption spectra, rheological properties, and surface tension, in addition to the observation of droplet formation. The results indicate that PEG macromolecules could change the aggregate groups of Red 218 molecules into smaller ones through hydrophobic interactions and separation effect. The addition of PEG into the dye solution increased the viscosity and decreased the surface tension. In the whole shear rate range tested, the 10% and 20% PEG400, as well as the 30% PEG200 dye solutions, showed good Newtonian fluid behavior. PEG macromolecules improved the droplet formation of the dye solutions. Increasing the PEG400 concentration to 30% and 40% resulted in elimination of the formation of satellites and the formation of ideal droplets at 10,000 Hz jetting frequency. A 30% PEG600-dye solution with the Z value of 4.6 formed the best spherical droplets at 10,000 Hz and produced perfect color images on cotton fabrics.

Bubble Entrapment in Sprayed Films

2014 ◽  
Author(s):  
A. Dalili ◽  
S. Chandra ◽  
J. Mostaghimi ◽  
H. T. Charles Fan ◽  
J. C. Simmer
Keyword(s):  
Surface Tension ◽  
Film Thickness ◽  
The Other ◽  
Bubble Motion ◽  
Sauter Mean Diameter ◽  
Glass Substrates ◽  
Buoyancy Forces ◽  
Mean Diameter ◽  
Imagej Software ◽  
Bubble Movement

A compressed air sprayer was used to spray model paint onto two glass substrates at the same time. Afterwards, one glass substrate was placed on a LED light source and still photographs were taken from the top using a DSLR camera with a timer system. The other substrate was put on a balance to record weight. Pictures and weight measurements were taken at 5 second intervals for 15 minutes. The sprayed film thickness was varied. The pictures were analyzed using ImageJ software. Bubble Count vs. Time, Sauter Mean Diameter (SMD) of Bubbles vs. Time as well as Weight vs. Time was plotted. It was seen that the pace of weight loss was faster for thinner films. The rate of bubble escape also depended on film thickness. It took a longer time for thicker films to lose the bubbles entrapped in them. In the first 30 seconds, large bubbles escaped due to buoyancy forces and afterwards surface-tension driven flows became dominant. There was also a lot of bubble movement in thicker films. The effect of gravity was studied as well. Gravity did not affect the bubble escape rate since a downward facing film had the same bubble count as an upward facing film confirming that bubble motion was not due to buoyancy forces alone. However, the SMD of bubbles in a downward facing film was larger than an upward facing film. Buoyancy is not a factor in bubble escape from the downward facing film and only surface-tension driven flows play a role.

PERFORMANCE COMPARISON OF DENOISING METHODS FOR HISTORICAL DOCUMENTS

2015 ◽  
Vol 77 (22) ◽  
Author(s):  
Sayed Muchallil ◽  
Fitri Arnia ◽  
Khairul Munadi ◽  
Fardian Fardian
Keyword(s):  
Image Processing ◽  
Processing Technique ◽  
Performance Comparison ◽  
The Other ◽  
Historical Documents ◽  
Median Filtering ◽  
Document Images ◽  
Post Processing ◽  
Binary Images ◽  
Complete Procedure

Image denoising plays an important role in image processing.  It is also part of the pre-processing technique in a binarization complete procedure that consists of pre-processing, thresholding, and post-processing.  Our previous research has confirmed that the Discrete Cosine Transform (DCT)-based filtering as the new pre-processing process improved the performance of binarization output in terms of recall and precision. This research compares three classical denoising methods; Gaussian, mean, and median filtering with the DCT-based filtering. The noisy ancient document images are filtered using those classical filtering methods. The outputs of this process are used as the input for Otsu, Niblack, Sauvola and NICK binarization methods. Then the resulted binary images of the three classical methods are compared with those of DCT-based filtering. The performance of all denoising algorithms is evaluated by calculating recall and precision of the resulted binary images.  The result of this research is that the DCT based filtering resulted in the highest recall and precision as compared to the other methods. 

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