scholarly journals Influence of Deposition Condition on Y2O3Coatings Produced by Pulsed Electrophoretic Deposition

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Hidetoshi Miyazaki ◽  
Asumi Ichikawa ◽  
Hisao Suzuki ◽  
Toshitaka Ota
Keyword(s):  
Aqueous Solution ◽  
Citric Acid ◽  
Bias Voltage ◽  
Electrophoretic Deposition ◽  
Second Step ◽  
Deposition Condition ◽  
Nanoparticle Suspension ◽  
Heat Treated ◽  
Deposited Film ◽  
Deposition Conditions

Y2O3nanoparticle suspension aqueous solution was prepared using citric acid. Then, Y2O3film was deposited using this solution with pulsed electrophoretic deposition (EPD). A dense Y2O3film of 25.7 μm thickness was obtained with deposition conditions of 0.5 wt% Y2O3concentration, bias voltage of 0.5 V, and bias frequency of 1 kHz. The respective resistivities of the as-deposited film and films heat-treated at 200°C and 400°C were 2.84 × 103 Ω·cm, 5.36 × 104 Ω·cm, and 2.05 × 106 Ω·cm. A 59.8 μm thick dense Y2O3film was obtained using two-step deposition with change of the bias voltage: a first step of 0.5 V and a second step of 2.0 V.

Effect of Hot Water Treatment with Organic Additives in Fresh Cut Carrot

2021 ◽  
Vol 7 (1) ◽  
pp. 1-9
Author(s):  
Taslima Ayesha Aktar Nasrin ◽  
◽  
Latifa Yasmin ◽  
Most Sadia Arfin ◽  
Mohammad Mainuddin Molla ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Sodium Chloride ◽  
Citric Acid ◽  
Respiration Rate ◽  
Sensory Quality ◽  
Beta Carotene ◽  
Bacterial Count ◽  
Total Bacterial Count ◽  
Heat Treated ◽  
Fresh Cut

Fresh cut carrot (Daucus carota L.) slices were treated with hot (60°C) water and hot aqueous solution (2% sodium chloride, 2% citric acid and 10% lime juice) for 1 min and then surface water was removed. Following treatment, fresh-cut carrot slices were kept in a polypropylene (PP) box and stored in a refrigerator (4±1°C and 50±5% RH) for 12 days. The effectiveness of the treatments in extending shelf life was evaluated by determining respiration rate, firmness, weight loss, external colour, whiteness index (WI), some chemical parameters (ascorbic acid content, TSS, acidity, pH, total sugar, reducing sugar and beta carotene), total bacterial count (TBC) and sensory quality. The highest increment of WI (48.4%) was observed without heat-treated carrot slices. On the other hand, WI was increased by 12.1% and 21.7% in carrot slices treated with hot aqueous solution of 2% citric acid and with hot aqueous solution of 2% sodium chloride respectively at 12 days of storage. On the 12th day of storage, fresh-cut carrot treated with hot aqueous solution of 2% citric acid scored 7.3 and the rest of the sample scored less than 4.5 (indicate as unacceptable) in overall acceptability. Carrot slices treated with hot aqueous solution of 2% citric acid and 2% sodium chloride retained a minimum number of TBC and delayed changes in WI, external colour and beta carotene content compared to without heat-treated carrot slices. Keywords: Citric acid, respiration rate, sensory quality, sodium chloride, total bacterial count, whiteness index

Green Electrospinning and Crosslinking of Polyvinyl Alcohol/Citric Acid

2015 ◽  
Vol 32 ◽  
pp. 32-42 ◽  
Author(s):  
Jing Jing Shi ◽  
En Long Yang
Keyword(s):  
Heat Treatment ◽  
Aqueous Solution ◽  
Citric Acid ◽  
Polyvinyl Alcohol ◽  
X Ray Diffraction ◽  
Heat Treated ◽  
Acid Aqueous Solution ◽  
Ft Ir ◽  
Citric Acid Content ◽  
Nanofiber Membranes

The present study reports green electrospinning of polyvinyl alcohol (PVA) / citric acid nanofiber membranes, and the membranes were then crosslinked by heat treatment. The electric conductivity of the PVA aqueous solution increases rapidly and the growth slows down along with the increase of citric acid content. The viscosity of 13 wt% PVA aqueous solutions with citric acid had a small increase and remained stable in one week, which was suitable for electrospinning fibers. Porous, interconnected nonwoven nanofiber membranes were electrospun from a thoroughly mixing of PVA/ citric acid aqueous solution. The membranes were then heat treated at 140 °C for 2 h. The postelectrospinning crosslinked nanofiber membranes were insoluble in water, while the non-crosslinked electrospun nanofiber membranes dissolved instantaneously. FT-IR spectrum, X-ray diffraction, and DSC thermograms reveal that crosslinking of PVA nanofiber membranes occurred through esterfication reaction during heat treatment.

scholarly journals Fabrication of Transparent Mg(OH)2 Thin Films by Drop-Dry Deposition

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 724
Author(s):  
Tong Li ◽  
Masaya Ichimura
Keyword(s):  
Thin Films ◽  
Aqueous Solution ◽  
Optical Properties ◽  
Surface Morphology ◽  
Magnesium Hydroxide ◽  
Dry Deposition ◽  
Visible Range ◽  
Substrate Heating ◽  
Water Effects ◽  
Deposition Conditions

Magnesium hydroxide (Mg(OH)2) thin films were deposited by the drop-dry deposition (DDD) method using an aqueous solution containing Mg(NO3)2 and NaOH. DDD was performed by dropping the solution on a substrate, heating-drying, and rinsing in water. Effects of different deposition conditions on the surface morphology and optical properties of Mg(OH)2 thin films were researched. Films with a thickness of 1−2 μm were successfully deposited, and the Raman peaks of Mg(OH)2 were observed for them. Their transmittance in the visible range was 95% or more, and the bandgap was about 5.8 eV. It was found that the thin films have resistivity of the order of 105 Ωcm. Thus, the transparent and semiconducting Mg(OH)2 thin films were successfully prepared by DDD.

Citric acid modified waste cigarette filters for adsorptive removal of methylene blue dye from aqueous solution

2021 ◽  
pp. 50655
Author(s):  
Aafia Tehrim ◽  
Min Dai ◽  
Xiange Wu ◽  
Malik Muhammad Umair ◽  
Imran Ali ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Citric Acid ◽  
Blue Dye ◽  
Methylene Blue Dye ◽  
Adsorptive Removal

Inerte Amminkomplexe als mehrwertige Kationsäuren in wäßriger Lösung / Inert Ammine Complexes as Multivalent Cationic Acids in Aqueous Solution

1980 ◽  
Vol 35 (9) ◽  
pp. 1096-1103 ◽  
Author(s):  
Matthias Kretschmer ◽  
Lutwin Labouvie ◽  
Karl-W. Quirin ◽  
Helmut Wiehn ◽  
Ludwig Heck
Keyword(s):  
Aqueous Solution ◽  
Ionic Strength ◽  
Spectrophotometric Method ◽  
Complex Cation ◽  
Aqua Ligand ◽  
Second Step ◽  
Acidity Constants ◽  
Ammine Complexes ◽  
Temperature Variations ◽  
Enthalpy Changes

Acidity constants of ammine complexes of tetravalent platinum in aqueous solutions have been determined by a spectrophotometric method at very low ionic strengths and extrapolated to zero ionic strength. Temperature variations of pK-values (25 °C and 50 °C) yield thermodynamic parameters for two successive deprotonation steps of hexaammineplatinum(IV), pentaamminechloroplatinum(IV), and tris(ethylenediamine)pla- tinum(IV) complexes and for the deprotonation of pentaammineaquacobalt(III) ion.The enthalpy changes for the first and second steps are similar and range from 50 to 75 kJ/mole while for the aqua ligand of Co(III) 33 kJ/mole are found. The very large dif­ference in the entropy changes (about 70 to 80 J/K mole for the first step and -10 to + 20 J/K mole for the second step) is interpreted by a model of solvation change. The primary hydration sphere of strongly oriented and immobilized water dipoles around the highly charged complex cation is transformed to a hydrogen-bonded solvation sheath when the electric field of the complex is weakened upon release of the first proton.

Electrophoretic Deposition of Titania Thin Films: Influence of Deposition Time on Microstructural and Optical Properties of the Coatings

2013 ◽  
Vol 829 ◽  
pp. 917-921
Author(s):  
Saber Ghannadi ◽  
Hossein Abdizadeh ◽  
Mohammad Reza Golobostanfard
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Electrophoretic Deposition ◽  
Deposition Time ◽  
Colloidal Suspension ◽  
Vis Spectroscopy ◽  
Titania Films ◽  
Titania Sol ◽  
Deposited Film ◽  
Deposited Films

Titania thin films were prepared by electrophoretic deposition at various deposition times (1, 5 and 10 min) in constant applied potential (5 V). For this purpose, modified titania sol was prepared as a colloidal suspension. The influence of deposition time on the thickness and optical properties of titania films was investigated. Scanning electron microscope images illustrate compact and homogeneous titania films deposited on FTO substrates. The results show that the film thickness increases with increasing the deposition time. It could be inferred from UV-Vis spectroscopy that increasing the thickness of deposited film causes higher absorbance at UV region. Also, increasing the deposition time from 1 to 5 min leads to increase in optical band gap of the deposited films.

scholarly journals Adsorption of heavy metals and methylene blue from aqueous solution with citric acid modified peach stone

2018 ◽  
Vol 53 (11) ◽  
pp. 1678-1688 ◽  
Author(s):  
Junhua Yan ◽  
Guihong Lan ◽  
Haiyan Qiu ◽  
Chao Chen ◽  
Yongqiang Liu ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Aqueous Solution ◽  
Methylene Blue ◽  
Citric Acid

scholarly journals Citric Acid Capped CdS Quantum Dots for Fluorescence Detection of Copper Ions (II) in Aqueous Solution

Nanomaterials ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 32 ◽  
Author(s):  
Zhezhe Wang ◽  
Xuechun Xiao ◽  
Tong Zou ◽  
Yue Yang ◽  
Xinxin Xing ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Quantum Dots ◽  
Citric Acid ◽  
Limit Of Detection ◽  
Copper Ions ◽  
High Sensitivity ◽  
Fluorescence Sensor ◽  
Cds Quantum Dots ◽  
Detection Range ◽  
Cds Qds

Citric acid capped CdS quantum dots (CA-CdS QDs), a new assembled fluorescent probe for copper ions (Cu2+), was synthesized successfully by a simple hydrothermal method. In this work, the fluorescence sensor for the detection of heavy and transition metal (HTM) ions has been extensively studied in aqueous solution. The results of the present study indicate that the obtained CA-CdS QDs could detect Cu2+ with high sensitivity and selectivity. It found that the existence of Cu2+ has a significant fluorescence quenching with a large red shifted (from greenish-yellow to yellowish-orange), but not in the presence of 17 other HTM ions. As a result, Cu2S, the energy level below the CdS conduction band, could be formed at the surface of the CA-CdS QDs and leads to the quenching of fluorescence of CA-CdS QDs. Under optimal conditions, the copper ions detection range using the synthesized fluorescence sensor was 1.0 × 10‒8 M to 5.0 × 10‒5 M and the limit of detection (LOD) is 9.2 × 10‒9 M. Besides, the as-synthesized CA-CdS QDs sensor exhibited good selectivity toward Cu2+ relative to other common metal ions. Thus, the CA-CdS QDs has potential applications for detecting Cu2+ in real water samples.

scholarly journals Two-Step Separation of Chitin from Shrimp Shells Using Citric Acid and Deep Eutectic Solvents with the Assistance of Microwave

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 409 ◽  
Author(s):  
Dandan Zhao ◽  
Wen-Can Huang ◽  
Na Guo ◽  
Shuye Zhang ◽  
Changhu Xue ◽  
...  
Keyword(s):  
Citric Acid ◽  
Deep Eutectic Solvents ◽  
Second Step ◽  
X Ray Diffraction ◽  
X Ray ◽  
Shrimp Shells ◽  
Ft Ir ◽  
Scanning Electron ◽  
Ft Ir Spectroscopy

In this research, a two-step extraction approach was developed for chitin preparation from shrimp shells by utilizing citric acids and deep eutectic solvents (DESs), which effectively removed minerals and proteins. In the first step, minerals of shrimp shells were removed by citric acid, and the demineralization efficiency reached more than 98%. In the second step, the removal of protein was carried out using deep eutectic solvents with the assistance of microwave, and the deproteinization efficiency was more than 88%. The results of scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction analysis (XRD), and thermogravimetric analysis (TGA) showed that the quality of DES-prepared chitin was comparable to that of traditional acid/alkali-prepared chitin. These results were realized without utilizing hazardous chemicals, which are detrimental to the environment. This research indicates that a DES-based preparation approach has the potential for application in the recovery of biopolymers from natural resources.

Microstructure Characterization of the Reaction Interface between CBN Grain and Titanium-Deposited Film

2012 ◽  
Vol 538-541 ◽  
pp. 166-171
Author(s):  
Wen Feng Ding ◽  
Yang Min Liang ◽  
Jian He ◽  
Li Tang ◽  
Jie Yu ◽  
...  
Keyword(s):  
Heating Temperature ◽  
Cubic Boron Nitride ◽  
High Vacuum ◽  
Reaction Products ◽  
X Ray Diffraction ◽  
X Ray ◽  
Energy Dispersion Spectrometer ◽  
Heat Treated ◽  
Deposited Film

Cubic boron nitride (CBN) abrasive grains with surface titanium-deposited film were heat-treated during 550-950°C for 60 min under high vacuum circumstance. Detailed interfacial compounds analysis by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersion spectrometer (EDS), differential thermal analysis (DTA) indicates that the interfacial reactions are much dependent on the heating temperature to some extents, and the reaction products, TiN, TiB2 and TiB chiefly form the network structure. In particular, at 950°C the transition layers with excellent performance, CBN/TiB2/TiB/(TiB+TiN)/TiN/CBN, is realized.

Sign in / Sign up

Export Citation Format

Share Document