Crystallization of Unvulcanized Rubber at Different Temperatures

1946 ◽  
Vol 19 (4) ◽  
pp. 1145-1162 ◽  
Author(s):  
Lawrence A. Wood ◽  
Norman Bekkedahl
Keyword(s):  
Quantitative Data ◽  
Effect Of Temperature ◽  
X Ray Diffraction ◽  
General Study ◽  
Volume Changes ◽  
Experimental Conditions ◽  
X Ray ◽  
Vulcanized Rubber ◽  
Different Temperatures ◽  
Comprehensive Study

Abstract Crystals may be formed in natural rubber under varied experimental conditions. Different combinations of stretching and cooling have been used to induce crystallization in unvulcanized and in vulcanized rubber. The appearance and disappearance of crystals have been studied by observations of the volume, heat capacity, light absorption, birefringence, x-ray diffraction, hardness, and other mechanical properties. There has, however, been no comprehensive study of the effect of temperature on the crystallization. The present investigation was undertaken to explore this field. In the work reported here it has been the aim to study crystallization at different temperatures under the simplest possible conditions. The main features of the crystallization of vulcanized rubber have been shown to be similar to those of the crystallization of unvulcanized rubber, vulcanization decreasing the rate of crystallization. Consequently unvulcanized rubber was selected for study. Stretching obviously complicates the experimental conditions, and so was not employed. Of the different methods of measuring crystallization, it seems that change of volume is the simplest and best adapted to yielding quantitative data on the course of the crystallization or fusion. The present work is, therefore, concerned with a general study of the volume changes in unvulcanized rubber at different temperatures.

Effect of Growth Temperature on the Indium Incorporation in InGaN Epitaxial Films

2011 ◽  
Vol 287-290 ◽  
pp. 1456-1459 ◽  
Author(s):  
P. C Chang ◽  
C. L Yu ◽  
Y. W Jahn ◽  
S. J Chang ◽  
K. H Lee
Keyword(s):  
Optoelectronic Devices ◽  
Chemical Vapor ◽  
Epitaxial Films ◽  
Effect Of Temperature ◽  
X Ray Diffraction ◽  
Film Properties ◽  
X Ray ◽  
Different Temperatures ◽  
Peak Emission

InxGa1-xN epilayers have been grown by metalorganic chemical vapor deposition (MOCVD) at different temperatures between 740°C to 830°C. The thickness of InGaN film is 50nm for all samples. The incorporation of indium is found to increase with decreasing grown temperature. The optical properties and film quality of the samples have been investigated by photoluminescence (PL) system and X-ray diffraction (XRD). The Full Width at Half Maximum (FWHM) of PL and XRD decreases with increasing the grown temperature. We also found that the peak emission of PL shifts with changing the grown temperature. The effect of temperature on the film properties was determined. This understanding will lead to better quality control of the optoelectronic devices.

Effect of Temperature on the Phase Behaviors of Zircon by Carbothermal Reduction-Nitridation

2011 ◽  
Vol 492 ◽  
pp. 480-483 ◽  
Author(s):  
Li Yin ◽  
Zhao Hui Huang ◽  
You Guo Xu ◽  
Yue Tong Li ◽  
Yang Gai Liu ◽  
...  
Keyword(s):  
Energy Dispersive Spectroscopy ◽  
Carbothermal Reduction ◽  
Raw Material ◽  
Effect Of Temperature ◽  
X Ray Diffraction ◽  
Scanning Electronic Microscopy ◽  
Electronic Microscopy ◽  
X Ray ◽  
Different Temperatures ◽  
Phase Behaviors

Phase behaviors of zircon at different temperatures via carbothermal reduction-nitridation were investigated in this study. By using zircon as raw material, with carbon coke as reducing agent, the influence of reaction temperatures (1450, 1500, 1550 and 1600 °C, respectively) on phase behaviors and microstructure of the products was characterized by X-ray diffraction analysis (XRD), scanning electronic microscopy (SEM) and energy dispersive spectroscopy (EDS). The results shows that by carbothermal reduction-nitridation, the main phases in the final products of zircon are m-ZrO2, c-ZrO2, β-SiC, ZrN and β-Si3N4at different temperatures for 4 hours.

Effect of Temperature on Fe3O4 Magnetic Nanoparticles Prepared by Coprecipitation Method

2014 ◽  
Vol 900 ◽  
pp. 172-176 ◽  
Author(s):  
Ji Mei Niu ◽  
Zhi Gang Zheng
Keyword(s):  
Magnetic Nanoparticles ◽  
Coprecipitation Method ◽  
Effect Of Temperature ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Magnetic Carriers ◽  
Average Grain Size ◽  
Or Gene ◽  
Block Temperature

The Fe3O4 magnetic nanoparticles obtained by the aqueous coprecipitation method are characterized systematically using scanning electron microscope, X-ray diffraction and vibrating sample magnetometer. These magnetic nanoparticles are spheric, dispersive, and have average grain size of 50 nm. The size and magnetic properties of Fe3O4 nanoparticles can be tuned by the reaction temperature. All samples exhibit high saturation magnetization (Ms=53.4 emu·g-1) and superparamagnetic behavior with a block temperature (TB) of 215K. These properties make such Fe3O4 magnetic nanoparticles worthy candidates for the magnetic carriers of targeted-drug or gene therapy in future.

scholarly journals Zeolite NaP1 Functionalization for the Sorption of Metal Complexes with Biodegradable N-(1,2-dicarboxyethyl)-D,L-aspartic Acid

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2518
Author(s):  
Dorota Kołodyńska ◽  
Yongming Ju ◽  
Małgorzata Franus ◽  
Wojciech Franus
Keyword(s):  
Experimental Data ◽  
Aspartic Acid ◽  
Ph Value ◽  
Complexing Agents ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Modified Zeolite ◽  
X Ray ◽  
Slow Release Fertilizers ◽  
Pseudo Second Order

The possibility of application of chitosan-modified zeolite as sorbent for Cu(II), Zn(II), Mn(II), and Fe(III) ions and their mixtures in the presence of N-(1,2-dicarboxyethyl)-D,L-aspartic acid, IDHA) under different experimental conditions were investigated. Chitosan-modified zeolite belongs to the group of biodegradable complexing agents used in fertilizer production. NaP1CS as a carrier forms a barrier to the spontaneous release of the fertilizer into soil. The obtained materials were characterized by Fourier transform infrared spectroscopy (FTIR); surface area determination (ASAP); scanning electron microscopy (SEM-EDS); X-ray fluorescence (XRF); X-ray diffraction (XRD); and carbon, hydrogen, and nitrogen (CHN), as well as thermogravimetric (TGA) methods. The concentrations of Cu(II), Zn(II), Mn(II), and Fe(III) complexes with IDHA varied from 5–20 mg/dm3 for Cu(II), 10–40 mg/dm3 for Fe(III), 20–80 mg/dm3 for Mn(II), and 10–40 mg/dm3 for Zn(II), respectively; pH value (3–6), time (1–120 min), and temperature (293–333 K) on the sorption efficiency were tested. The Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin adsorption models were applied to describe experimental data. The pH 5 proved to be appropriate for adsorption. The pseudo-second order and Langmuir models were consistent with the experimental data. The thermodynamic parameters indicate that adsorption is spontaneous and endothermic. The highest desorption percentage was achieved using the HCl solution, therefore, proving that method can be used to design slow-release fertilizers.

scholarly journals A Superhydrophobic, Antibacterial, and Durable Surface of Poplar Wood

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1885
Author(s):  
Xinyu Wu ◽  
Feng Yang ◽  
Jian Gan ◽  
Zhangqian Kong ◽  
Yan Wu
Keyword(s):  
Stearic Acid ◽  
Antibacterial Properties ◽  
Alkali Resistance ◽  
Poplar Wood ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Temperatures ◽  
Acid And Alkali Resistance ◽  
The Stability

The silver particles were grown in situ on the surface of wood by the silver mirror method and modified with stearic acid to acquire a surface with superhydrophobic and antibacterial properties. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray energy spectroscopy (XPS) were used to analyze the reaction mechanism of the modification process. Scanning electron microscopy (SEM) and contact angle tests were used to characterize the wettability and surface morphology. A coating with a micro rough structure was successfully constructed by the modification of stearic acid, which imparted superhydrophobicity and antibacterial activity to poplar wood. The stability tests were performed to discuss the stability of its hydrophobic performance. The results showed that it has good mechanical properties, acid and alkali resistance, and UV stability. The durability tests demonstrated that the coating has the function of water resistance and fouling resistance and can maintain the stability of its hydrophobic properties under different temperatures of heat treatment.

scholarly journals Hydrothermal Ageing and Its Effect on Fracture Load of Zirconia Dental Implants

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3103
Author(s):  
Laurent Gremillard ◽  
Agnès Mattlet ◽  
Alexandre Mathevon ◽  
Damien Fabrègue ◽  
Bruno Zberg ◽  
...  
Keyword(s):  
Dental Implants ◽  
Fracture Load ◽  
Accelerated Ageing ◽  
Dental Ceramics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dental Restorations ◽  
Different Temperatures ◽  
Mechanical Performances ◽  
Kinetics Of

Due to growing demand for metal-free dental restorations, dental ceramics, especially dental zirconia, represent an increasing share of the dental implants market. They may offer mechanical performances of the same range as titanium ones. However, their use is still restricted by a lack of confidence in their durability and, in particular, in their ability to resist hydrothermal ageing. In the present study, the ageing kinetics of commercial zirconia dental implants are characterized by X-ray diffraction after accelerated ageing in an autoclave at different temperatures, enabling their extrapolation to body temperature. Measurements of the fracture loads show no effect of hydrothermal ageing even after ageing treatments simulated a 90-year implantation.

scholarly journals Modeling of magneto-conductivity of bismuth selenide: a topological insulator

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Yogesh Kumar ◽  
Rabia Sultana ◽  
Prince Sharma ◽  
V. P. S. Awana
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Single Crystal ◽  
Single Crystals ◽  
X Ray Diffraction ◽  
Field Range ◽  
X Ray ◽  
Bulk Carriers ◽  
Different Temperatures

AbstractWe report the magneto-conductivity analysis of Bi2Se3 single crystal at different temperatures in a magnetic field range of ± 14 T. The single crystals are grown by the self-flux method and characterized through X-ray diffraction, Scanning Electron Microscopy, and Raman Spectroscopy. The single crystals show magnetoresistance (MR%) of around 380% at a magnetic field of 14 T and a temperature of 5 K. The Hikami–Larkin–Nagaoka (HLN) equation has been used to fit the magneto-conductivity (MC) data. However, the HLN fitted curve deviates at higher magnetic fields above 1 T, suggesting that the role of surface-driven conductivity suppresses with an increasing magnetic field. This article proposes a speculative model comprising of surface-driven HLN and added quantum diffusive and bulk carriers-driven classical terms. The model successfully explains the MC of the Bi2Se3 single crystal at various temperatures (5–200 K) and applied magnetic fields (up to 14 T).

Preparation of Ultra–Fine La3NbO7 Powder by Solid State Reaction

2012 ◽  
Vol 512-515 ◽  
pp. 158-161 ◽  
Author(s):  
Ling Dai ◽  
Qiang Xu ◽  
Shi Zhen Zhu ◽  
Ling Liu
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Single Phase ◽  
Thermal Barrier ◽  
X Ray Diffraction ◽  
X Ray ◽  
Granular Particle ◽  
Fine Particle Size ◽  
Ultra Fine Particle ◽  
Different Temperatures

As a new candidate material for the ceramic layer in thermal barrier coatings (TBCs) system, La3NbO7 was synthesized with La2O3 powder and Nb2O5 powder by solid state reaction. The stating powders with a mole ratio of La to Nb of 3:1 were mixed and then the mixture was calcined under the different temperatures(800°C, 1000°C, 1200°C) and dwell times(2h, 6h, 10h). The phase structure of the powder was observed by X–ray diffraction(XRD), and the microstructure of the sample was observed by scanning electron microscope(SEM). The effect of calcination temperature and dwell Time on the phase formation were examined. The results indicate that the La3NbO7 powder with single phase can be synthesized successfully at 1200°C for 10h in air, and the La3NbOsub>7 powders synthesized have an ultra-fine particle size of 0.5˜1µm with a granular particle shape. With the temperature increasing, LaNbO4/sub> was synthesized firstly and then La3NbO7 was synthesized with a mole ratio of La2O3 to LaNbO4 of 1:1.

scholarly journals Theoretical study of the properties of X-ray diffraction moiré fringes. II. Illustration of angularly integrated moiré images

2019 ◽  
Vol 75 (4) ◽  
pp. 610-623
Author(s):  
Jun-ichi Yoshimura
Keyword(s):  
Incident Wave ◽  
Angular Width ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Acta Cryst ◽  
Low Contrast ◽  
X Ray ◽  
Moiré Fringes ◽  
Wide Range ◽  
Fringe Patterns

Using a theory of X-ray diffraction moiré fringes developed in a previous paper, labelled Part I [Yoshimura (2015). Acta Cryst. A71, 368–381], the X-ray moiré images of a silicon bicrystal having a weak curvature strain and an interspacing gap, assumed to be integrated for an incident-wave angular width, are simulation-computed over a wide range of crystal thicknesses and incident-wave angular width, likely under practical experimental conditions. Along with the simulated moiré images, the graphs of characteristic quantities on the moiré images are presented for a full understanding of them. The treated moiré images are all of rotation moiré. Mo Kα1 radiation and the 220 reflection were assumed in the simulation. The results of this simulation show that fringe patterns, which are significantly modified from simple straight fringes of rotation moiré, appear in some ranges of crystal thicknesses and incident-wave angular width, due to a combined effect of Pendellösung oscillation and an added phase difference from the interspacing gap, under the presence of a curvature strain. The moiré fringes which slope to the perpendicular direction to the diffraction vector in spite of the assumed condition of rotation moiré, and fringe patterns where low-contrast bands are produced with a sharp bend of fringes arising along the bands are examples of the modified fringe pattern. This simulation study provides a wide theoretical survey of the type of bicrystal moiré image produced under a particular condition.

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