Design optimization and stability enhancement of modified inter-digital capacitive humidity transducer with cobalt ferrite nanoparticles as dielectric

2019 ◽  
Vol 42 (4) ◽  
pp. 917-923
Author(s):  
Jiss Paul ◽  
Jacob Philip
Keyword(s):  
Recovery Time ◽  
Room Temperature ◽  
Cobalt Ferrite ◽  
Dynamic Range ◽  
Ferrite Nanoparticles ◽  
Sensitive Layer ◽  
Humidity Transducer ◽  
The Stability ◽  
Stability Enhancement ◽  
Sensing Characteristics

A modified inter-digital capacitive (IDC) transducer for relative humidity (RH) measurement is fabricated by coating a thick film of polyvinyl alcohol (PVA) on the structure. The effective capacitance of the sensor, measured at 1MHz, increases with RH at room temperature. The RH sensing characteristics of PVA coated IDC transducer are analysed in terms of its sensitivity, dynamic range, frequency response, repeatability and recovery time. It is found that the stability of such a PVA based RH transducer improves remarkably by diffusing nanoparticles of CoFe2O4 in the PVA layer. A standard deviation of ± 0.05 and ± 0.01 for a sensitive layer with pure PVA and PVA-CoFe2O4 combination respectively results in a measurement error of ± 0.005 and ± 0.003.

A novel method to evaluate nanofluid stability using multivariate image analysis

2017 ◽  
Vol 9 (39) ◽  
pp. 5826-5833 ◽  
Author(s):  
Maykon Alves Lemes ◽  
Denilson Rabelo ◽  
Anselmo Elcana de Oliveira
Keyword(s):  
Image Analysis ◽  
Cobalt Ferrite ◽  
Ferrite Nanoparticles ◽  
Multivariate Image Analysis ◽  
Cobalt Ferrite Nanoparticles ◽  
Insulating Oil ◽  
Novel Method ◽  
Nanofluid Stability ◽  
The Stability ◽  
Multivariate Image

A multivariate image analysis (MIA)-based approach in conjunction with chemometrics is proposed to evaluate the stability of nanofluids prepared by dispersing cobalt ferrite nanoparticles in mineral insulating oil.

scholarly journals Biological synthesis of cobalt ferrite nanoparticles

2012 ◽  
Vol 2 (1) ◽  
pp. 9 ◽  
Author(s):  
Anal K. Jha ◽  
Kamal Prasad
Keyword(s):  
Room Temperature ◽  
Cobalt Ferrite ◽  
Low Cost ◽  
Ferrite Nanoparticles ◽  
Biological Synthesis ◽  
Vibrating Sample Magnetometer ◽  
X Ray ◽  
Cobalt Ferrite Nanoparticles ◽  
Transmission Electron ◽  
Individual Nanoparticles

A low-cost green and reproducible yeast (<em>Saccharomyces cerevisiae</em>) mediated biosynthesis of cobalt ferrite nanoparticles is reported. The synthesis is performed at close to room temperature in the laboratory. X-ray, Fourier transform infrared spectroscopy and high resolution transmission electron microscopy analyses are performed to ascertain the formation of cobalt ferrite nanoparticles. Individual nanoparticles, as well as a very few aggregate having the size of 3-15 nm, were found. The vibrating sample magnetometer measurement showed superparamagnetic behavior in cobalt ferrite nanoparticles. The mechanism involved in the biosynthesis of cobalt ferrite nanoparticles has also been discussed.

scholarly journals Theoretical and Experimental Research on Ammonia Sensing Properties of Sulfur-Doped Graphene Oxide

Chemosensors ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 220
Author(s):  
Yao Yu ◽  
Zhijia Liao ◽  
Fanli Meng ◽  
Zhenyu Yuan
Keyword(s):  
Graphene Oxide ◽  
Electrical Properties ◽  
Recovery Time ◽  
Room Temperature ◽  
Gas Sensing ◽  
Theoretical Models ◽  
Ammonia Sensing ◽  
Doped Graphene ◽  
Response And Recovery ◽  
Sensing Characteristics

In this paper, gas sensing characteristics of sulfur-doped graphene oxide (S-GO) are firstly presented. The results of the sensing test revealed that, at room temperature (20 °C), S-GO has the optimal sensitivity to NH3. The S-GO gas sensor has a relatively short response and recovery time for the NH3 detection. Further, the sensing limit of ammonia at room temperature is 0.5 ppm. Theoretical models of graphene and S-doped graphene are established, and electrical properties of the graphene and S-doped graphene are calculated. The enhanced sensing performance was ascribed to the electrical properties’ improvement after the graphene was S-doped.

scholarly journals FTIR and Electrical Study of Dysprosium Doped Cobalt Ferrite Nanoparticles

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Hemaunt Kumar ◽  
Jitendra Pal Singh ◽  
R. C. Srivastava ◽  
P. Negi ◽  
H. M. Agrawal ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Spinel Structure ◽  
Room Temperature ◽  
Cobalt Ferrite ◽  
Spinel Phase ◽  
Ferrite Nanoparticles ◽  
Absorption Bands ◽  
Octahedral Sites ◽  
Electrical Study

We have studied the role of Dy3+ doping on the XRD, TEM, FTIR, and dielectric and electrical properties of CoFe2O4 at room temperature. Cubic spinel phase of CoFe2−xDyxO4 (x = 0.00, 0.05, 0.10, and 0.15) was synthesized by using different sintering temperatures (300, 500, 700, and 900°C). The two absorption bands ν1 and ν2 are observed in Fourier transform infrared spectroscopy (FTIR) spectra corresponding to the tetrahedral and octahedral sites, which show signature of spinel structure of the sample. For the sample sintered at 300°C, the dielectric constant is almost unchanged with the frequency at the particular concentrations of x = 0.00 and 0.05. Similar result is obtained for the sample sintered at 500°C (x = 0.10, 0.15), 700°C (x = 0.05, 0.10, and 0.15), and 900°C (x = 0.05, 0.10). An increase in the dielectric constant was observed for the undoped cobalt ferrite sintered at 500, 700, and 900°C. The values of electrical resistivity of the materials vary from ~105 to 109 Ω-cm.

scholarly journals Recent developments in the synthesis and stability of metal ferrite nanoparticles

2019 ◽  
Vol 102 (1) ◽  
pp. 61-72
Author(s):  
Muhammad Imran Din ◽  
Faria Rafique ◽  
Muhammad Sadaf Hussain ◽  
Hafiz Arslan Mehmood ◽  
Sadia Waseem
Keyword(s):  
Cobalt Ferrite ◽  
Sodium Citrate ◽  
Sodium Dodecyl ◽  
Ferrite Nanoparticles ◽  
Synthetic Methods ◽  
Recent Developments ◽  
Iron Ferrite ◽  
Mixed Nanoparticles ◽  
The Stability ◽  
Co Precipitation

This article presents a comprehensive review on the synthesis and stability of ferrite nanoparticles such as nickel ferrite (NiFe2O4), zinc ferrite (ZnFe2O4), manganese ferrite (MnFe2O4), iron ferrite (Fe2O3), cobalt ferrite (CoFe2O4) and also mixed nanoparticles. Different synthetic methods for ferrite nanoparticles have been reviewed such as co-precipitation, thermal decomposition and hydrothermal, microwave-assisted and sonochemical methods. The effect on the stability of different capping agents like canola oil, glycerol, sodium dodecyl, sodium citrate, oleic acid, Triton-100 and sodium dodecyl benzene sulfonates has also been studied.

Methods for the Concentration of Bovine Ac-Globulin (Factor V)

1961 ◽  
Vol 06 (03) ◽  
pp. 435-444 ◽  
Author(s):  
Ricardo H. Landaburu ◽  
Walter H. Seegers
Keyword(s):  
Room Temperature ◽  
Barium Carbonate ◽  
Deae Cellulose ◽  
Reducing Agents ◽  
Factor V ◽  
Isoelectric Precipitation ◽  
Stabilizing Agent ◽  
Bovine Plasma ◽  
The Stability

SummaryAn attempt was made to obtain Ac-globulin from bovine plasma. The concentrates contain mostly protein, and phosphorus is also present. The stability characteristics vary from one preparation to another, but in general there was no loss before 1 month in a deep freeze or before 1 week in an icebox, or before 5 hours at room temperature. Reducing agents destroy the activity rapidly. S-acetylmercaptosuccinic anhydride is an effective stabilizing agent. Greatest stability was at pH 6.0.In the purification bovine plasma is adsorbed with barium carbonate and diluted 6-fold with water. Protein is removed at pH 6.0 and the Ac-globulin is precipitated at pH 5.0. Rivanol and alcohol fractionation is followed by chromatography on Amberlite IRC-50 or DEAE-cellulose. The final product is obtained by isoelectric precipitation.

Tyrosine-Selective Bioconjugation with Iminoxyl Radicals

2020 ◽  
Author(s):  
Katsuya Maruyama ◽  
Takashi Ishiyama ◽  
Yohei Seki ◽  
Kounosuke Oisaki ◽  
Motomu Kanai
Keyword(s):  
Reaction Time ◽  
Steric Hindrance ◽  
Room Temperature ◽  
Water Soluble ◽  
Light Irradiation ◽  
Sodium Ascorbate ◽  
Iminoxyl Radical ◽  
Short Reaction Time ◽  
Modified Peptides ◽  
The Stability

A novel Tyr-selective protein bioconjugation using the water-soluble persistent iminoxyl radical is described. The conjugation proceeded with high Tyr-selectivity and short reaction time under biocompatible conditions (room temperature in buffered media under air). The stability of the conjugates was tunable depending on the steric hindrance of iminoxyl. The presence of sodium ascorbate and/or light irradiation promoted traceless deconjugation, restoring the native Tyr structure. The method is applied to the synthesis of a protein-dye conjugate and further derivatization to azobenzene-modified peptides.

Circular dichroism and infrared study of β-turn formation in repeat peptides of elastin

1987 ◽  
Vol 52 (5) ◽  
pp. 1356-1361
Author(s):  
S. Abdel Rahman ◽  
M. Elsafty ◽  
A. Hattaba
Keyword(s):  
Circular Dichroism ◽  
Solid State ◽  
Ir Spectra ◽  
Chain Length ◽  
Room Temperature ◽  
Infrared Study ◽  
Feature Characteristic ◽  
C 50 ◽  
The Stability ◽  
Circular Dichroïsm

The conformation of elastin-like peptides Boc-Ala-Pro-Gly-Val-APEGM, Boc-Ala-Pro-Gly-Val-Gly-Val-APEGM, Boc-Ala-Pro-Gly-Val-Ala-Pro-Gly-Val-Gly-Val-APEGM, Boc-Ala-Pro-Gly-Val-Gly-Val-Ala-Pro-Gly-Val-Gly-Val-APEGM were examined in solution using circular dichroism at 30 °C, 50 °C, and 70 °C and in solid state by IR at room temperature. The studies show that the β-turn is a significant conformational feature for peptides under investigation in solution at 30 °C and 50 °C, but at 70 °C the tetra, hexa, and decapeptides show the CD feature characteristic of the β-structure while the dodecapeptide spectra show the presence of β-turn which indicates the stability of the β-turn at this chain length. The IR spectra show that in the solid state at room temperature all investigated peptides assume essentially a β-turn except the tetrapeptide which present evidence of antiparallel β-structure. The β-turn contribution in the IR spectra increases with the increase of the chain length of the peptide.

Cholesterol in Serum and Lipoprotein Fractions

1956 ◽  
Vol 2 (3) ◽  
pp. 145-159 ◽  
Author(s):  
Joseph T Anderson ◽  
Ancel Keys
Keyword(s):  
Human Serum ◽  
Total Cholesterol ◽  
Filter Paper ◽  
Room Temperature ◽  
Paper Electrophoresis ◽  
Cholesterol Content ◽  
Intraindividual Variability ◽  
Detailed Data ◽  
The Stability ◽  
Source Of Error

Abstract 1. Methods are described for the separation, by paper electrophoresis and by cold ethanol, of α- and β-lipoproteins in 0.1 ml. of serum, with subsequent analysis of cholesterol in the separated portions. 2. It is shown that both methods of separation yield separated fractions containing substantially the same amounts of cholesterol. 3. Detailed data are given on the errors of measurement for total cholesterol and for cholesterol in the separated lipoprotein fractions. 4. Studies are reported on the stability of cholesterol in stored serum and on paper electrophoresis strips. It is shown that simple drying on filter paper causes no change in cholesterol content and yields a product that is stable for many weeks at ordinary room temperature. 5. The sources of variability in human serum cholesterol values are examined and it is shown that spontaneous intraindividual variability is a much greater source of error than the errors of measurement with these methods.

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