scholarly journals MWCNTs/ZnO Nanofibers Fabrication, Properties and Applications

2019 ◽  
Vol 16 (1) ◽  
pp. 196-211
Author(s):  
Magda Dawy Badry
Keyword(s):  
Food Packaging ◽  
Fiber Diameter ◽  
Aluminum Foil ◽  
Hexagonal Wurtzite Structure ◽  
Organic Precursor ◽  
X Ray ◽  
Before And After ◽  
Zno Nanofibers ◽  
The Mean ◽  
Xrd Patterns

Electrospun MWCNTs nanofibers (CNF1, CNF2 and CNF3) with different concentrations of MWCNTs (0.3, 1.5, 2 wt%), respectively, were deposited on Aluminum foil substrates.  Also,Zinc AcetatedihydrateZn(CH3COO)2.2H2O (ZNF) and MWCNTs/zinc acetate (CZNF)nanofiberswere deposited on Aluminum foil substratesand annealed in the presence of oxygen at 400 oC. The resultant fibers were characterized using X-ray differaction (XRD), scanning electron microscope with energy dispersive X-Ray spectrophotometry (SEM,EDX), Fourier transform infrared (FTIR). SEM,EDX and FTIR exhibited a total decomposition of the organic precursor after calcination and formation of zinc oxide (ZONF and CZONF). The mean fiber diameter was found to be increased with increasing MWCNTs concentration and ranged 490-767 nm. XRD patterns indicated that ZnO was corundum with the hexagonal wurtzite structure. The crystallite size of ZONF and CZONF were determined by shurrer equation to be26 and  29.7  nm, respectively. The optical analysis indicated that the percentage transmittance increased after calcination.The band gap for the electrospun fibers before and after calcination was calculated. CZONF nanofibers have elec­trical properties similar to those of semiconductors. The testedcompounds CNF2, CNF3, CZNF and CZONF exhibited different activities against the bacteriaand yeast pathogen Candidaalbicans. CZNF compound is the most active against the bacteria and yeast pathogen. So, these compounds can be used as food packaging.  

scholarly journals Synthesis of Nanoscale Zerovalent Iron (nZVI) Supported on Biochar for Chromium Remediation from Aqueous Solution and Soil

2019 ◽  
Vol 16 (22) ◽  
pp. 4430 ◽  
Author(s):  
Haixia Wang ◽  
Mingliang Zhang ◽  
Hongyi Li
Keyword(s):  
Aqueous Solution ◽  
Photoelectron Spectroscopy ◽  
Zero Valent Iron ◽  
Zerovalent Iron ◽  
X Ray ◽  
Nanoscale Zerovalent Iron ◽  
Before And After ◽  
Pseudo Second Order ◽  
Xrd Patterns ◽  
Co Precipitation

Maize straw biochar-supported nanoscale zero-valent iron composite (MSB-nZVI) was prepared for efficient chromium (Cr) removal through alleviating the aggregation of zero-valent iron particles. The removal mechanism of MSB-nZVI was investigated by scanning electron microscopy with energy dispersive X-ray (SEM-EDX), X-ray diffractometry (XRD), and X-ray photoelectron spectroscopy (XPS). Cr(VI) removal from aqueous solution by MSB-nZVI was greatly affected by pH and initial concentration. The removal efficiency of Cr(VI) decreased with increasing pH, and the removal kinetics followed the pseudo-second-order model. XRD patterns of MSB-nZVI before and after reaction showed that reduction and precipitation/co-precipitation (FeCr2O4, Fe3O4, Fe2O3) occurred with the conversion of Cr(VI) to Cr(III) and Fe(0) to Fe(II)/Fe(III). The produced precipitation/co-precipitation could be deposited on the MSB surface rather than being only coated on the surface of nZVI particles, which can alleviate passivation of nZVI. For remediation of Cr(VI)-contaminated saline–alkali soil (pH 8.6–9.0, Cr 341 mg/kg), the released amount of Cr(VI) was 70.7 mg/kg, while it sharply decreased to 0.6–1.7 mg/kg at pH 4.0–8.0, indicating that the saline–alkali environment inhibited the remediation efficiency. These results show that MSB-nZVI can be used as an effective material for Cr(VI) removal from aqueous solution and contaminated soil.

scholarly journals Imaging in the Evaluation of Endoscopic or Surgical Treatment for Achalasia

2016 ◽  
Vol 2016 ◽  
pp. 1-4
Author(s):  
Diego Palladino ◽  
Andrea Mardighian ◽  
Marilina D’Amora ◽  
Luca Roberto ◽  
Francesco Lassandro ◽  
...  
Keyword(s):  
Surgical Treatment ◽  
Digestive Tract ◽  
Endoscopic Treatment ◽  
Heller Myotomy ◽  
Esophageal Achalasia ◽  
Pneumatic Dilation ◽  
X Ray ◽  
Before And After ◽  
High Operative Risk ◽  
The Mean

Purpose.Aim of the study is to evaluate the efficacy of the endoscopic (pneumatic dilation) versus surgical (Heller myotomy) treatment in patients affected by esophageal achalasia using barium X-ray examination of the digestive tract performed before and after the treatment.Materials and Methods.19 patients (10 males and 9 females) were enrolled in this study; each patient underwent a barium X-ray examination to evaluate the esophageal diameter and the height of the barium column before and after endoscopic or surgical treatment.Results.The mean variation of oesophageal diameter before and after treatment is −2.1 mm for surgery and 1.74 mm for pneumatic dilation (OR 0.167, CI 95% 0.02–1.419, andP: 0.10). The variations of all variables, with the exception of the oesophageal diameter variation, are strongly related to the treatment performed.Conclusions.The barium X-ray study of the digestive tract, performed before and after different treatment approaches, demonstrates that the surgical treatment has to be considered as the treatment of choice of achalasia, reserving endoscopic treatment to patients with high operative risk and refusing surgery.

scholarly journals Investigation of Ferrimagnetic Sr-hexaferrite Nanocrystals for Clinical Hyperthermia

2021 ◽  
pp. X
Author(s):  
Burcu ERTUĞ
Keyword(s):  
Crystallite Size ◽  
Room Temperature ◽  
Vibrating Sample Magnetometry ◽  
Sem Images ◽  
Ceramic Method ◽  
X Ray ◽  
The Mean ◽  
Xrd Patterns ◽  
Potential Use ◽  
Scanning Electron

Sr-hexaferrite samples were produced via the conventional ceramic method. X-ray diffractometry (XRD) patterns confirmed the single nanocrystal phase as Sr-hexaferrite where any pattern peaks of unreacted Fe2O3 phase were  not detected. The mean crystallite size values were determined to be 44.12±3.4nm and 41.2±3.2nm for SHF-O1 and SHF-O2, respectively. The chemical bonding peaks of our sample indicated that the structure of Sr-hexaferrite formation was confirmed by FTIR spectra result. Scanning electron microscopy (SEM) images indicated clearly observed porosity regions with relative densities as high as 94% and 87% for SHF-O1 and SHF-O2 samples.The vibrating sample magnetometry (VSM) of each sample at 2K and under a magnetic field of 10 kOe yielded saturation magnetizations, Ms of 93.5 and 94.1 emu/g; remanence values, Mr of 76.4 and  67.8 emu/g for SHF-O1 and SHF-O2, respectively. The magnetization loops of both samples indicated a soft ferrimagnetic behaviour in which the saturation magnetizations were higher than those measured  at room temperature in the previous studies. The coercivities, Hc were measured to be 150Oe for both samples. The squareness values, SQR (Mr/Ms) were measured to be high, approximately 0.82 and 0.72 for SHF-O1 and SHF-O2, respectively. Depending on the adequate values of magnetization and coercivity along with small mean crystallite size and low porosity values of the obtained Sr-hexaferrite samples, we estimate that these samples are likely to be evaluated further for the potential use as thermoseeds in the field of clinical hyperthermia.

Effect of iodide treatment on iodine concentration and volume of endemic non-toxic goitre in childhood

1985 ◽  
Vol 108 (1) ◽  
pp. 44-50 ◽  
Author(s):  
B. Leisner ◽  
B. Henrich ◽  
D. Knorr ◽  
R. Kantlehner
Keyword(s):  
Thyroid Volume ◽  
Iodine Concentration ◽  
Thyroxine Binding Globulin ◽  
X Ray ◽  
Thyroxine Therapy ◽  
Iodine Supplementation ◽  
Before And After ◽  
The Mean ◽  
Young Subjects ◽  
Normal Controls

Abstract. In a total of 195 children and adolescents of both sex (mean age 12.9, range 5–17 years) with endemic non-toxic goitre the thyroidal iodine concentration (IC) was determined using X-ray fluorescent scanning on admission and during iodine (100 μg daily) and l-thyroxine (3 μg/kg body weight daily) treatment respectively. Additionally the thyroid volume was measured sonographically in a longitudinal study including 46 patients before and after 4–8 months of iodine supplementation (100 μg daily). The IC was 305 ± 144 μg/g. It compared well with that of adult goitre patients (288 ± 109 μg/g) and was significantly inferior to the value of normal controls (389 ± 170 μg/g). Under l-thyroxine therapy the IC further decreased (243 ± 144 μg/g), whereas patients receiving iodide showed an increase of the IC (570 ± 197 μg/g). The mean TSH level fell from 2.3 ± 0.9 μU/ml to 1.4 ± 0.6 μU/ml. The average T4/TBG (thyroxine binding globulin) ratio showed a slight increase which, however, was not significant. The mean goitre volume decreased by 40%. It was evidenced that iodide is useful not only in the prophylaxis of non-toxic goitre but also as a more physiologic treatment than thyroid hormones, at least for young subjects with simple diffuse goitres.

Dry Effect of Cementitious Materials on Testing Results of X-Ray CT

2012 ◽  
Vol 450-451 ◽  
pp. 187-192 ◽  
Author(s):  
Jian De Han ◽  
Wei Sun ◽  
Gang Hua Pan
Keyword(s):  
Cement Paste ◽  
Three Dimensional ◽  
Cementitious Materials ◽  
Drying Process ◽  
X Ray ◽  
Before And After ◽  
X Ray Computed ◽  
The Mean ◽  
The Impact ◽  
Gray Values

In this study three-dimensional X-ray computed tomography (X-ray CT) is used to investigate the testing results differences of cement paste and mortar before and after drying. It can be found that the mean gray values of paste and mortar before drying are bigger than after drying, and the impact of drying on cement paste is more serious than mortar. In addition, the porosity of non-drying cement paste and mortar is 1.10% and 0.43%, while that of drying cement paste and mortar is 1.55% and 0.70%, respectively. So, the porosity of paste and mortar markedly increases after drying process. The numbers of pores of paste and mortar sharply increase after drying process in particular between 0.01mm3 and 0.1mm3. The impact of drying on smaller pores is more serious than bigger pores.

scholarly journals On-chip ZnO nanofibers prepared by electrospinning method for NO2 gas detection

2018 ◽  
Vol 27 (4) ◽  
pp. 317 ◽  
Author(s):  
Van Hoang Nguyen ◽  
Van Dung Nguyen ◽  
Quang Dat Do ◽  
Thi Minh Nguyet Quan ◽  
Manh Hung Chu ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Hexagonal Wurtzite Structure ◽  
X Ray Diffraction ◽  
Electrospinning Technique ◽  
X Ray ◽  
Electrospinning Method ◽  
Resistance Modulation ◽  
Zno Nanofibers ◽  
On Chip ◽  
Gas Response

In the present study, on-chip ZnO nanofibers were fabricated by means of the electrospinning technique followed by a calcination process at 600 oC towards the gas sensor application. The morphology, composition, and crystalline structure of the as-spun and annealed ZnO nanofibers were investigated by field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX), and X-ray diffraction (XRD), respectively. The findings show that spider-net like ZnO nanofibers with a diameter of 60 – 100 nm were successfully synthesized without any incorporation of impurities into the nanofibers. The FESEM images also reveal that each nanofiber is composed of many nanograins. The combination of experimental and calculated X-ray diffraction data indicate that ZnO nanofibers were crystallized in hexagonal wurtzite structure. For the gas sensing device application, the ZnO nanofibers-based sensors were tested with the nitrogen dioxide gas in the temperature range of 200 oC to 350 oC and concentrations from 2.5 ppm to 10 ppm. The sensing property results indicate that at the optimal working temperature of 300 oC, the ZnO nanofibers-based sensors exhibited a maximum response of 30 and 166 times on exposure of 2.5 and 10 ppm NO2 gas, respectively. The presence of nanograins within nanofibers, which results in further intensification of the resistance modulation, is responsible for such high gas response.

Impact of foaming agent and nanoparticle fillers on the properties of irradiated rubber

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Hanan M. Eyssa ◽  
Soma A. El Mogy ◽  
Hussein A. Youssef
Keyword(s):  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Radiation Dose ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Foaming Agent ◽  
X Ray ◽  
Sem Image ◽  
Before And After ◽  
Xrd Patterns

AbstractA sponge rubber nanocomposite based on styrene–butadiene rubber (SBR)/nanoclay (montmorillonite, MMT) or nano-calcium carbonate (CaCO3) fillers with various foaming agent contents was produced by a simple technique, roll milling. The nanoparticles were examined by different techniques, such as X-ray fluorescence (XRF), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), and Fourier-transform infrared (FT–IR). The sponge rubber nanocomposites were characterized by scanning electron microscopy (SEM) image analysis before and after exposures to radiation doses, as well as by the XRD patterns for the unirradiated samples. The different properties of the obtained nanocomposites, including their foaming degree, tensile strength, elongation at break, and thermal conductivity, were also investigated. The foam composites containing nano-CaCO3 possessed the best cell and crosslinking densities and mechanical properties among the other composites, while its foaming degree was the lowest. The results indicated that the thermal conductivity was reduced by increasing the foaming agent concentration. However, it increased as the radiation dose increased, and the optimum radiation dose was obtained at 75 kGy. The foam containing MMT exhibited an intermediate behavior while high thermal conductivity was recorded for the foam containing the CaCO3 nanoparticles.

Chlorhexidine Adsorption in Hydroxyapatite and Alginate Microspheres by Extrusion in Zinc and Calcium Chloride

2016 ◽  
Vol 720 ◽  
pp. 25-30 ◽  
Author(s):  
Nadia Mohammed Elmassalami Ayad ◽  
Daniel Navarro da Rocha ◽  
Andrea Machado Costa ◽  
Marcelo Henrique Prado da Silva
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Chloride ◽  
Crystalline Phase ◽  
X Ray ◽  
Zn Concentration ◽  
Vis Spectroscopy ◽  
Before And After ◽  
Xrd Patterns ◽  
Scanning Electron

In this work, the adsorption of a low-concentration solution of chlorhexidine (CHX), an antimicrobial drug, in hydroxyapatite (HA) and alginate microspheres was studied. The microspheres were formed by extrusion of a 1:10 mixture of alginate and HA in two different divalent solutions: CaCl2 and ZnCl2. UV-Vis spectroscopy showed that the microspheres adsorbed approximately half of the chlorhexidine in solution, which was initially at 0.2%. XRD patterns obtained prior adsorption confirmed the presence of HA as the only crystalline phase. Scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX) analysis were performed before and after CHX adsorption. The spheres produced in CaCl2 solution did not show significant change after adsorption. However, samples obtained in ZnCl2 solution showed a different microstructure, with the presence of crystals with a high Zn concentration. X-Ray Fluorescence (XRF) confirmed the presence of ZnO in the samples after CHX absorption.

X-Ray Diffraction Patterns of Oil Palm Empty Fruit Bunch Fibers with Varying Crystallinity

2015 ◽  
Vol 1087 ◽  
pp. 321-328 ◽  
Author(s):  
Fatin Afifah Ahmad Kuthi ◽  
Khairiah Haji Badri ◽  
Azlin Mohmad Azman
Keyword(s):  
Acid Hydrolysis ◽  
Oil Palm ◽  
Empty Fruit Bunch ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Before And After ◽  
Different Temperatures ◽  
Diffraction Patterns ◽  
Xrd Patterns

Crystallinity of oil palm fiber from empty fruit bunch (EFB) with and without tretaments was studied by analyzing the X-ray diffraction (XRD) pattern. In this paper, we focused on the effect of acid hydrolysis onto EFB on the crystallinity of the extracted cellulose. The reaction was carried out by soaking EFB in 1% (v/v) aqueous sulfuric acid (H2SO4) at different temperatures of 120, 130 and 140°C for 1 h. The XRD patterns significantly showed changes in the 2θ peaks before and after the treatment. These changes were described in term of polymorphs type present, reflection and allomorphs of the samples. XRD peak high and XRD deconvolution methods were used to calculate and compare the percentage of crystallinity of untreated EFB (UT-EFB) and acid hydrolyzed samples (AH-EFB). Based on the calculation, increment of about 1.3 times and 1.5 times were achieved by using WAXS and XRD deconvolution methods respectively. This is due to the removal of amorphous part contributed by lignin, hemicellulose and cellulose. Fourier Transform infrared (FTIR) spectra showed the presence of similar peaks in AH-EFB and commercial microcrystalline cellulose (C-MCC) at 1427, 1315, 895 and 1022 cm-1. The micrographic features showed the acid hydrolysis had successfully took place and separated the EFB microfibrils bundles.

scholarly journals Statistically Coherent Calibration of X-Ray Fluorescence Spectrometry for Major Elements in Rocks and Minerals

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Surendra P. Verma ◽  
Sanjeet K. Verma ◽  
M. Abdelaly Rivera-Gómez ◽  
Darío Torres-Sánchez ◽  
Lorena Díaz-González ◽  
...  
Keyword(s):  
Linear Regression ◽  
Major Elements ◽  
Chemical Data ◽  
Confidence Limits ◽  
Total Uncertainty ◽  
X Ray ◽  
Analytical Instruments ◽  
Before And After ◽  
The Mean ◽  
Mean Concentration

We applied both the ordinary linear regression (OLR) and the new uncertainty weighted linear regression (UWLR) models for the calibration and comparison of a XRF machine through 59 geochemical reference materials (GRMs) and a procedure blank sample. The mean concentration and uncertainty data for the GRMs used for the calibrations (Supplementary Materials) (available here) filewere achieved from an up-to-date compilation of chemical data and their processing from well-known discordancy and significance tests. The drift-corrected XRF intensity and its uncertainty were determined from mostly duplicate pressed powder pellets. The comparison of the OLR (linear correlation coefficient r∼0.9523–0.9964 and 0.9771–0.9999, respectively, for before and after matrix correction) and UWLR models (r∼0.9772–0.9976 and 0.9970–0.9999, respectively) clearly showed that the latter with generally higher values of r is preferable for routine calibrations of analytical procedures. Both calibrations were successfully applied to rock matrices, and the results were generally consistent with those obtained in other laboratories although the UWLR model showed mostly narrower confidence limits of the mean (slope and intercept) or lower uncertainties than the OLR. Similar sensitivity (∼2.69–46.17 kc·s−1·%−1 for the OLR and ∼2.78–59.69 kc·s−1·%−1 for the UWLR) also indicated that the UWLR could advantageously replace the OLR model. Another novel aspect is that the total uncertainty can be reported for individual chemical data. If the analytical instruments were routinely calibrated from the UWLR model, this action would make the science of geochemistry more quantitative than at present.

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