DEVELOPMENT OF A NON-CONTINUOUS MICRO-FLOW OPTO-WETTING DROPLET MANIPULATION TECHNOLOGY

2005 ◽  
Vol 17 (06) ◽  
pp. 293-299 ◽  
Author(s):  
MING-YIH LEE ◽  
HUNG-CHIA LIN ◽  
HUNG-WEI CHIANG ◽  
WEI-XUN LEE ◽  
XIAN-DONG HUANG
Keyword(s):  
Surface Tension ◽  
Uv Light ◽  
Liquid Droplet ◽  
Average Particle Size ◽  
Base Material ◽  
Material Surface ◽  
Average Particle ◽  
Hydrophilic Property ◽  
Manipulation System ◽  
Droplet Manipulation

The aim of this study is to develop a non-continuous droplet manipulation technology in contrast to conventional continuous flow micro-fluidic systems. The droplets were manipulated based on the proposed opto-wetting effect. In addition, an experimental ultraviolet (UV) light actuated droplet manipulation system was developed for verifying the opto-wetting droplet manipulation. The proposed opto-wetting effect was achieved by utilizing ultraviolet to activate oxidation-reduction mechanism of nano-TiO2 photo catalyst coated base material. The water-affinity of the base material will changed due to the decreased free-energy of the material surface. Therefore, the contact angle between the liquid droplet and base material will also be changed which facilitates droplet manipulability. The main components of the proposed ultraviolet (UV) light actuated droplet manipulation system include ultraviolet masking device, moving platform and main frame structure. System software and user interface were designed by using Microsoft Visual Basic 6.0 toolkit. Upon completion of the proposed system, experiments were carried out to verify system functionalities. Follow by the controlled variable optimization using Taguchi method and liquid droplet manipulation experiments. The experiment results indicate that by exposure to 6.8mW UV light, the surface tension and hydrophilic property of nano-TiO2 (anatase type, 3.5% concentration, PH 1.5, and with average particle size of 69 nm) coated base material will changed. The change of surface tension and hydrophilic property were critical for droplet manipulation. The moving speed of the liquid droplet was measured as 3.33mm/sec. The results suggest that the opto-wetting system may be effective to overcome the shortcoming of traditional opto-electrowetting technique. The proposed opto-wetting droplet manipulation system could potentially applied for manipulating biomedical or pathological test specimens in the future.

scholarly journals Surface Activity of Humic Acid and Its Sub-Fractions from Forest Soil

2021 ◽  
Vol 13 (15) ◽  
pp. 8122
Author(s):  
Shijie Tian ◽  
Weiqiang Tan ◽  
Xinyuan Wang ◽  
Tingting Li ◽  
Fanhao Song ◽  
...  
Keyword(s):  
Surface Tension ◽  
Particle Size ◽  
Humic Acid ◽  
Forest Soil ◽  
Surface Activity ◽  
Self Assembly ◽  
Average Particle Size ◽  
Gaussian Model ◽  
Exponential Model ◽  
Average Particle

Surface activity of humic acid (HA) and its six sub-fractions isolated from forest soil were characterized by surface tension measurements, dynamic light scattering, and laser doppler electrophoresis. The surface tension of HA and its sub-fractions reduced from 72.4 mN·m−1 to 36.8 mN·m−1 in exponential model with the increasing concentration from 0 to 2000 mg·L−1. The critical micelle concentration (CMC) and Z-average particle size ranged from 216–1024 mg·L−1 and 108.2–186.9 nm for HA and its sub-fractions, respectively. The CMC have related with alkyl C, O-alkyl C, aromatic C, and carbonyl C (p < 0.05), respectively, and could be predicted with the multiple linear regression equation of CMC, CMC = 18896 − 6.9 × C-296 × alkyl C-331 × aromatic C-17019 × H/C + 4054 × HB/HI (p < 0.05). The maximum particle size was 5000 nm after filtered by a membrane with pore size of 450 nm, indicating HA and its sub-fractions could progressed self-assembly at pH 6.86. The aggregate sizes of number-base particle size distributions were mainly in six clusters including 2 ± 1 nm, 5 ± 2 nm, 10 ± 3 nm, 21 ± 8 nm, 40 ± 10 nm, and >50 nm analyzed by Gaussian model that maybe due to the inconsistency of the components and structures of the HA sub-fractions, requiring further study. It is significance to explore the surface activity of HA and its sub-fractions, which is helpful to clarify the environmental behavior of HA.

Photocatalytically Active Cotton Fabrics Produced with Anatase Synthesized Using a Low-Temperature Sol-Gel Process

2018 ◽  
Vol 762 ◽  
pp. 408-412
Author(s):  
Raivis Eglītis ◽  
Gundars Mežinskis
Keyword(s):  
Photocatalytic Activity ◽  
Uv Light ◽  
Sol Gel ◽  
Average Particle Size ◽  
Synthesis Method ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Sol Gel Process ◽  
Anatase Nanoparticles ◽  
Pre Treatment

In this work two different hydrosols were used to impregnate a commercially available cotton fabric with anatase nanoparticles to give it photocatalytic activity. To increase the activity, different pre-treatment methods were applied. The nanoparticle size was determined using dynamic light scattering and x-ray diffraction and the fabrics were examined using scanning electron microscopy. Photocatalytic activity was measured using the degradation of methyl-orange while irradiating the samples with UV light. The synthesis method allowed to produce anatase with an average particle size of 32 to 37 nm depending on the synthesis method used.

scholarly journals Volatile Organic Compound (VOC) Removal via Photocatalytic Oxidation Using TiO2 Coated Nanofilms

2017 ◽  
Vol 15 (7) ◽  
pp. 491-501
Author(s):  
Sunun KHAMI ◽  
Wipawee KHAMWICHIT ◽  
Ratthapol RANGKUPAN ◽  
Kowit SUWANNAHONG
Keyword(s):  
Bacterial Cellulose ◽  
Photocatalytic Oxidation ◽  
Uv Light ◽  
Average Particle Size ◽  
Average Particle ◽  
Experimental Conditions ◽  
Electrospinning Technique ◽  
Photocatalytic Reactor ◽  
Toluene Concentration ◽  
Spinning Process

In this paper, toluene removal via photocatalytic oxidation using TiO2 dip coated nanofilms is presented. Nanofilms were synthesized from bacterial cellulose using the electrospinning technique. The physical properties of the nanofilms were analyzed by scanning electron microscopy (SEM). The ratio of bacterial cellulose/nylon used in the spinning process was 0.165:1. The results from SEM showed that the structure of the TiO2 composite nanofilms was rutile crystalline with an average particle size of 20 nm, and synthesized nanofilms had an average size of 20 - 30 nm. The band gap energies of TiO2-dip coated nanofilms ranged from 3.18 - 3.21 eV. SEM results of TiO2 coated nanofilms suggested that the TiO2 was rather uniformly distributed onto the surface of the nanofilms. The actual amount of TiO2 coated on the nanofilms was estimated using thermogravimetric analysis (TGA) for 1x1 cm2 surface area. It was found that 0.1852, 0.2897 and 0.7275 mg of TiO2 were coated on the surface of the nanofilms for 1, 2.5 and 5 % (weight) TiO2 dosage, respectively. The photocatalytic activity of the nanofilms was tested for the removal of gaseous toluene in a photocatalytic reactor. Experimental conditions were set as follows: UV light intensity of approximately 2.7 mW.cm-2, flow rate of 0.2 L.min-1, and an initial toluene concentration of about 200±20 ppm, and a retention time at 200 min. The degradation rate of toluene increased with increasing dosage of TiO2 from 1, 2.5 and 5 %. The nanofilms at a 5 % dosage yielded the highest removal efficiency of 92.71 %, followed by the 2.5 and 1 % dosage, respectively.

scholarly journals Photocatalytic Degradation of Rhodamine B and Malachite Green by Cobalt Sulfide Nanoparticles

2022 ◽  
Vol 34 (2) ◽  
pp. 331-341
Author(s):  
Gunjan Chauhan ◽  
Manjeet Sharma
Keyword(s):  
Malachite Green ◽  
Rhodamine B ◽  
Degradation Rate ◽  
Uv Light ◽  
Average Particle Size ◽  
Single Step ◽  
Cobalt Sulfide ◽  
Cds Nanoparticles ◽  
Average Particle ◽  
Cobalt Sulphide

Present study reports the simple and cost effective thermolytic method for the synthesis of cobalt sulphide nanoparticles (CoS NPs). The PXRD spectrum of cobalt sulphide (CdS) nanoparticles exhibited four peaks indexed to (100), (101), (102) and (110) crystal planes. The average particle size observed from DLS and PXRD was in the range 4.81-12.20 nm. A blue shift in band gap was observed from UV-visible spectra. The FESEM and TEM studies revealed that cobalt sulfide nanoparticles are of cubic and rectangle shapes. FTIR spectra of hexadecylamine (HDA) capped CoS NPs exhibited ν(N-H) absorption around 3350-3240 cm–1. The stretching frequency due to ν(Co-S) appeared in the region 334-332 cm–1. Proton NMR (1H) spectra of CoS NPs showed signals at nearly same positions as in case of capping agent, suggesting its capping nature. ESI-MS analyses of cobalt sulphide nanoparticles displayed peak at m/z = 124.93 corresponding to the [CoS2]+ ion. Thermogravimetric curves showed single step decomposition corresponding to 84.28% weight loss and 15.72% as final residue due to cobalt oxide. The degradation rate of rhodamine B and malachite green dyes after irradiating with sunlight showed 92-94% degradation while irradiated with UV-light of 4.8 eV show much slower degradation rate.

scholarly journals Synthesis and Characterization of Co2+ Ions Doped ZnS-CdS Composite Nanopowder

2020 ◽  
Author(s):  
Madhavi Jonnalagadda
Keyword(s):  
Average Particle Size ◽  
Exchange Interactions ◽  
Host Lattice ◽  
Material Surface ◽  
Precipitation Process ◽  
Average Particle ◽  
Magnetic Studies ◽  
Chemical Homogeneity ◽  
Ferromagnetic Nature ◽  
Co Precipitation

ZnS-CdS composite nano-powder doped with (0.01 mol %) Cobalt has been collected by a co-precipitation process at 300 K. The sample is characterized by structural, combined spectroscopic methods and magnetic studies. The prepared samples were belonging to cubic structure no impurity phases were observed. Doping of cobalt increase the neighborhood strain assessment and a decreases lattice constants decides from x-ray diffraction data. The crystallite size is 10.42nm. From UV-absorption and EPR studies revealed that the energy band gap of Co2+ doped ZnS-CdS composite nanopowder and extension of sp-d exchange interactions and common d-d transitions. The variation in the energy bandgap varies as a function of cobalt concentration is due to structural modification. Photoluminescence spectrum reveals the defect-related emissions and shows the formation of luminescence. FT-IR spectrum confirmed the feature vibrational manner of Zn, Cd, O&ndash;H and sulfide ions are in the host lattice. The doping-induced magnetic properties are studied by vibrating sample magnetometer which matches with the theoretical values besides ferromagnetic nature. Magnetic studies confirm the ferromagnetic nature of the material. Surface morphology and chemical homogeneity studies were carried out by using SEM with EDAX. Transmission electron microscope recommends the crystalline nature of nanoparticles, with average particle size is of the order of 20-100nm.

scholarly journals Methylene Blue Dye Photocatalytic Degradation over Synthesised Fe3O4/AC/TiO2 Nano-Catalyst: Degradation and Reusability Studies

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2360
Author(s):  
Seyedehmaryam Moosavi ◽  
Rita Yi Man Li ◽  
Chin Wei Lai ◽  
Yusliza Yusof ◽  
Sinyee Gan ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Uv Light ◽  
Agricultural Waste ◽  
Average Particle Size ◽  
Blue Dye ◽  
Average Particle ◽  
Step Procedure ◽  
Nano Catalyst ◽  
One Step ◽  
The Stability

In this study, activated carbon (AC) from coconut shell, as a widely available agricultural waste, was synthesised in a simple one-step procedure and used to produce a magnetic Fe3O4/AC/TiO2 nano-catalyst for the degradation of methylene blue (MB) dye under UV light. Scanning electron microscopy revealed that TiO2 nanoparticles, with an average particle size of 45 to 62 nm, covered the surface of the AC porous structure without a reunion of its structure, which according to the TGA results enhanced the stability of the photocatalyst at high temperatures. The photocatalytic activities of synthesised AC, commercial TiO2, Fe3O4/AC, and Fe3O4/AC/TiO2 were compared, with Fe3O4/AC/TiO2 (1:2) exhibiting the highest catalytic activity (98%). Furthermore, evaluation of the recovery and reusability of the photocatalysts after treatment revealed that seven treatment cycles were possible without a significant reduction in the removal efficiency.

Fluorescence in the assessment of the share of a key component in the mixing of feed

2020 ◽  
Vol 18 (1) ◽  
pp. 1086-1092
Author(s):  
Dominika Barbara Matuszek
Keyword(s):  
Granulometric Composition ◽  
Uv Light ◽  
High Reliability ◽  
Average Particle Size ◽  
Average Particle ◽  
Particle Sizes ◽  
Mixing Process ◽  
Multicomponent Mixtures ◽  
Computer Image Analysis ◽  
Significant Statistical Difference

AbstractThis paper presents the results of the mixing of a multicomponent feed for cattle. Three types of mixtures with different proportions of individual components and granulometric composition were selected. After the mixing process, the fraction of the key component (tracer) was determined. Tracer consisted of crushed grains of yellow maize, which was wet treated with a 0.01% solution of Rhodamine B. A tracer with two different average particle sizes d1 = 2.0 mm and d2 = 1.25 mm was introduced into the mixture. Then, the sample was illuminated with UV light, and the content of the tracer in the sample was evaluated using the computer image analysis. In addition, the tracer was separated to determine its fraction using a laboratory scale. From the obtained results, the high reliability of the fluorescence optical method for the evaluation of the homogeneity of granular multicomponent mixtures was proved. It was also observed that slightly better results were obtained for a tracer with a larger average particle size (d = 2.0 mm), although the comparative analysis did not indicate a significant statistical difference in the results in each series of tests.

The Effect of Surface Roughness on the Erosion of Mild Steel

2004 ◽  
Author(s):  
Stacy A. Nelson ◽  
Michael J. Baker ◽  
William F. Deans
Keyword(s):  
Surface Roughness ◽  
Mild Steel ◽  
Average Particle Size ◽  
Roughness Parameter ◽  
Operating Conditions ◽  
Wave Number ◽  
Material Surface ◽  
Average Particle ◽  
Initial Surface ◽  
Surface Roughness Parameter

This paper investigates the relationship between the surface roughness parameter, Ra, and the erosion of the material surface. Jet impingement tests were carried out on the surface of mild steel plates at an impact angle of 30 degrees to the material surface. The erosion test rig utilised sand as the erodent at a concentration of 2%wt, with average particle size of 270 μm. The average surface roughness Ra, of the test specimens ranged from 0.07 μm to 1.14 μm. The erosion damage was assessed by a unique application of the surface profilometry technique. In addition, by using Fast Fourier Transforms to convert the surface profile scans into wave-number spectra, the changes in the material surface after erosion exposure were easily monitored. The investigation showed that the surface roughness parameter plays a significant role in the erosion process, particularly in the initial stages. The operating conditions of the impinging jet were associated with an equilibrium condition, both for the surface roughness and the eroded depth. As a result, materials having an initial surface roughness value greater than the equilibrium Rae value showed a decrease in surface roughness, whereas those having an initial value less than the equilibrium value showed an increase in surface roughness. This trend was confirmed by the changes in the amplitudes of the wave-number spectra for each plate, over the erosion period. The eroded depth was maximum for the plate having the smallest difference between the initial Ra value and the equilibrium value Rae. This subsequently decreased as the deviation from the equilibrium value was increased.

scholarly journals Soy protein isolate-carboxymethyl cellulose conjugates with pH sensitivity for sustained avermectin release

2019 ◽  
Vol 6 (7) ◽  
pp. 190685 ◽  
Author(s):  
Long Chen ◽  
Hongjun Zhou ◽  
Li Hao ◽  
Huayao Chen ◽  
Xinhua Zhou
Keyword(s):  
Release Rate ◽  
Soy Protein ◽  
Carboxymethyl Cellulose ◽  
Uv Light ◽  
Average Particle Size ◽  
Soy Protein Isolate ◽  
Weibull Model ◽  
Protein Isolate ◽  
Toxicity Tests ◽  
Average Particle

Carboxymethyl cellulose (CMC) was grafted onto the surface of soy protein isolate (SPI) to obtain soy protein isolate-carboxymethyl cellulose conjugate (SPC). Avermectin (AVM) was hydrophobically encapsulated as a model drug to obtain SPC@AVM. The reaction between SPI and CMC was confirmed by infrared spectroscopy, thermal analysis and SDS-PAGE electrophoresis. The results of scanning electron microscopy showed that the average particle size of the drug-loaded microspheres was 129 nm and the shape of microspheres changed from block to spherical after the addition of AVM. After encapsulation of AVM, the absolute value of zeta potential was greater than 15 mV, which indicated better stability. Compared to AVM solution, SPC@AVM showed more wettability on the leaf surface and the contact angle on the leaves decreased from 71.64° to 57.33°. The maximum liquid holding capacity increased by 41.41%, from 8.85 to 12.52 mg cm −2 , which effectively reduced leaf loss. SPC@AVM also prevented UV photolysis, wherein the half-life was extended from 18 to 68 min when exposed to UV light. Moreover, toxicity tests showed that the encapsulation of AVM was beneficial to retain the insecticidal effect of AVM in the presence of ultraviolet light. The release rate of AVM showed pH responsiveness and the release rate under neutral conditions was faster than acidic and alkaline conditions. Moreover, the process conformed to the Weibull model.

scholarly journals Photo-Luminescence study of Ba3Gd1-x(BO3)3 : X Ce3+ phosphor

YMER Digital ◽  
2021 ◽  
Vol 20 (11) ◽  
pp. 75-82
Author(s):  
V. R Panse ◽  
Keyword(s):  
Blue Light ◽  
Uv Light ◽  
Average Particle Size ◽  
Photo Luminescence ◽  
Average Particle ◽  
Solution Combustion ◽  
Excitation Peak ◽  
Broad Absorption Band ◽  
Sem Image ◽  
Light Excitation

The polycrystalline powder sample of Ce3+ activated barium gadolinium borate phosphors Ba3Gd1-x(BO3)3 : X Ce3+(0.01 ≤ X ≤ 0.06 ) are prepared by solution combustion. Formation of phosphor in desired crystalline phase confirmed by powder XRD characterization & FTIR. A SEM image shows the irregular grains with average particle size 2.5μm. The excitation spectrum consists of a single broad absorption band from 200 to 400 nm with the prominent excitation peak at 343 nm [2F5/2 to 5D1 of Ce3+ ions]. Strongest emission peak of 488nm [5D1→ 2F5/2] and weak of 501nm [5D1→ 2F7/2] wavelength which is of blue light is observed at 343nm UV light excitation. Ba3Gd1-x(BO3)3 : X Ce3+ phosphor emits blue light under UV excitation. Maximum PL emission takes place at 3 mole percentage of Ce3+. Concentration quenching for Ce3+ ions is studied. Hence Ba3Gd1-x(BO3)3 : X Ce3+ is new UV excited blue emitting phosphor useful for UV/Blue chip WLEDs.

Sign in / Sign up

Export Citation Format

Share Document