scholarly journals Influences of Temperature on the Conversion of Ammonium Tungstate Pentahydrate to Tungsten Oxide Particles with Controllable Sizes, Crystallinities, and Physical Properties

2018 ◽  
Vol 16 (2) ◽  
pp. 124 ◽  
Author(s):  
Asep Bayu Dani Nandiyanto ◽  
Heli Siti Halimatul Munawaroh ◽  
Tedi Kurniawan ◽  
Ahmad Mudzakir
Keyword(s):  
Physicochemical Properties ◽  
Physical Properties ◽  
Undergraduate Students ◽  
Tungsten Trioxide ◽  
Model Material ◽  
Effect Of Temperature ◽  
Water Molecules ◽  
Ammonium Ions ◽  
Experimental Procedure ◽  
Ammonium Tungstate

The purpose of this study was to investigate influences of temperature on the conversion of ammonium tungstate pentahydrate (ATP) powder to tungsten trioxide (WO3) particles with controllable sizes, crystallinities, and physicochemical properties. In this study, we used a simple thermal decomposition method. In the experimental procedure, we explored the effect of temperature on the physicochemical properties of ATP by testing various heating temperatures (from 100 to 900 °C). The heated ATP samples were then characterized by a physical observation (i.e. color) and various analysis methods (i.e. a thermal gravimetric and differential thermal analysis, infrared spectroscopy, an X-ray diffraction, and a scanning electron microscope). Experimental results showed that increases in temperature had an impact to the decreases in particle size, the change in material crystallinity, and the change in physical properties (e.g. change of color from white, orange, to yellowish green). The relationships between the reaction temperatures and the physicochemical properties of the ATP were also investigated in detail along with the theoretical consideration and the proposal of the WO3 particle formation mechanism. In simplification, the phenomena can be described into three zones of temperatures. (1) Below 250 °C (release of water molecules and some ammonium ions).; (2) At 250-400 °C (release of water molecules and ammonium ions, restructurization of tungsten and oxygen elements, and formation of amorphous tungsten trioxide). (3) At higher than 400 °C (crystallization of tungsten trioxide). Since ATP possessed reactivity on temperature, its physicochemical properties changing could be observed easily, and the experimental procedure could be done easily. The present study will benefit not only for “chemistry and material science” but also potentially to be used as a model material for explaining the thermal behavior of material to undergraduate students (suitable used for a class and laboratory experiment and demonstration).

scholarly journals Preliminary Studies Regarding the Physicochemical Characteristics of Some Balsamic Vinegars

1970 ◽  
Vol 66 (2) ◽  
Author(s):  
Delia Mihaela TRUTA ◽  
Maria TOFANA ◽  
Sonia Ancuţa SOCACI ◽  
Rowena CHELEMAN
Keyword(s):  
Physicochemical Properties ◽  
Physical Properties ◽  
Quality Evaluation ◽  
Physicochemical Characteristics ◽  
Production Method ◽  
Chemical Information ◽  
Grape Must ◽  
The Third ◽  
The Future ◽  
Balsamic Vinegar

The aim of this work is to analyze the chemical and physical properties of balsamic vinegar, in order to improve the chemical information about this product, useful for its authentication and quality evaluation. Using three balsamic vinegars purchased in local markets as samples, this study investigated the labeling and the physicochemical properties of commercial concentrated balsamic vinegar in order to understand their production method and quality. Two of the samples were balsamic vinegars from Modena (BVM) and the third was a balsamic vinegar from Kalamata (BVK). According to the labels, all the balsamic vinegars samples were made of grape must and had an acidity of 6%. The appearance of the samples of vinegar differed significantly, but the acidity from the label was the same for all. Since people are paying much more attention to health, the number of concentrated vinegar products is expected to increase in the future. Thus, appropriate rules and physicochemical properties are required to regulate vinegar production and quality.

scholarly journals Konsentrasi Katalis dan Suhu Optimum pada Reaksi Esterifikasi menggunakan Katalis Zeolit Alam Aktif (ZAH) dalam Pembuatan Biodiesel dari Minyak Jelantah

2013 ◽  
Vol 14 (3) ◽  
pp. 219 ◽  
Author(s):  
Dwi Kartika ◽  
Senny Widyaningsih
Keyword(s):  
Physical Properties ◽  
Natural Zeolite ◽  
Oil And Gas ◽  
Catalyst Concentration ◽  
Waste Cooking Oil ◽  
Effect Of Temperature ◽  
Molar Ratio ◽  
Cooking Oil ◽  
Biodiesel Synthesis ◽  
Directorate General

Transesterification of waste cooking oil into biodiesel using KOH catalyst with and without esterification process usingactivated natural zeolite (ZAH) catalyst has been carried out. Activation of the zeolite was done by refluxing with HCl 6Mfor 30 min, followed calcining and oxydized at 500oC for 2 hours, consecutively. The transesterification without esterificationprocess were done using KOH catalyst 1% (w/w) from oil and methanol weight and oil/methanol molar ratio 1:6 at 60oC. Theesterification reaction was also done using ZAH catalyst then continued by transesterification using KOH catalyst inmethanol media. In order to study the effect of ZAH catalyst concentration at constant temperature, the catalysts werevaried, i.e. 0, 1, 2, and 3% (w/w). To investigate the effect of temperature, the experiments were done at various temperaturefrom 30, 45, 60, and 70oC at constant catalyst concentration. The conversion of biodiesel was determined by 1H-NMRspectrometer and physical properties of biodiesel were determined using ASTM standard methods. The results showedthat the transesterification using KOH catalyst without esterification produced biodiesel conversion of 53.29%. The optimumcondition of biodiesel synthesis via esterification process were reached at 60oC and concentration of ZAH catalyst of2% (w/w), that could give biodiesel conversion = 100.00%. The physical properties were conformed with biodiesel ASTM2003b and Directorate General of Oil and Gas 2006 specification.

scholarly journals Effects of the Temperature and the pH on the Main Protease of SARS-CoV-2: A Molecular Dynamics Simulation Study

2021 ◽  
Vol 12 (6) ◽  
pp. 7239-7248
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Root Mean Square ◽  
Dynamics Simulation ◽  
Effect Of Temperature ◽  
Water Molecules ◽  
Mean Square ◽  
Main Protease ◽  
Decreasing Ph ◽  
Increasing Temperature

The novel coronavirus, recognized as COVID-19, is the cause of an infection outbreak in December 2019. The effect of temperature and pH changes on the main protease of SARS-CoV-2 were investigated using all-atom molecular dynamics simulation. The obtained results from the root mean square deviation (RMSD) and root mean square fluctuations (RMSF) analyses showed that at a constant temperature of 25℃ and pH=5, the conformational change of the main protease is more significant than that of pH=6 and 7. Also, by increasing temperature from 25℃ to 55℃ at constant pH=7, a remarkable change in protein structure was observed. The radial probability of water molecules around the main protease was decreased by increasing temperature and decreasing pH. The weakening of the binding energy between the main protease and water molecules due to the increasing temperature and decreasing pH has reduced the number of hydrogen bonds between the main protease and water molecules. Finding conditions that alter the conformation of the main protease could be fundamental because this change could affect the virus’s functionality and its ability to impose illness.

(NH4)[B3PO6(OH)3]·0.5H2O

2007 ◽  
Vol 63 (11) ◽  
pp. i185-i185 ◽  
Author(s):  
Wei Liu ◽  
Jingtai Zhao
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Water Molecules ◽  
Hydrogen Bond Network ◽  
Ammonium Ions ◽  
One Dimensional ◽  
Bond Network ◽  
Solvothermal Conditions

The title compound, ammonium catena-[monoboro-monodihydrogendiborate-monohydrogenphosphate] hemihydrate, was obtained under solvothermal conditions using glycol as the solvent. The crystal structure is constructed of one-dimensional infinite borophosphate chains, which are interconnected by ammonium ions and water molecules via a complex hydrogen-bond network to form a three-dimensional structure. The water molecules of crystallization are disordered over inversion centres, and their H atoms were not located.

Science of Art and Analysis: A Mixture for Undergraduate Non-Specialists

1992 ◽  
Vol 267 ◽  
Author(s):  
W. Stanley Taft ◽  
James W. Mayer
Keyword(s):  
Physical Properties ◽  
Computer Science ◽  
Undergraduate Students ◽  
Analytical Methods ◽  
Art History ◽  
Analytical Techniques ◽  
Cornell University ◽  
The Third ◽  
Works Of Art ◽  
Modern Analytical

ABSTRACTAt Cornell University we are in the third year of teaching an interdisciplinary, undergraduate course on the physical properties and structures of works of Art, and the modern analytical methods used to investigate them: Art, Isotopes, and Analysis. The challenge is to explain concepts familiar to museum scientists and conservators to a group of 150 undergraduate students with a background that ranges from Art History to Computer Science. Painting techniques (Fresco, Tempera, Oil, etc.) are demonstrated to the class. The analytical techniques involve the interactions of electrons, photons, ions and neutrons with pigments and other materials. This instructional approach serves as an introduction to published analyses of works of art.

Radiothermal radiation method for aqueous solutions

2021 ◽  
Author(s):  
L.A. Morozova ◽  
S.V. Savel’ev
Keyword(s):  
Dielectric Properties ◽  
Alkali Metal ◽  
Thermal Radiation ◽  
Aqueous Solutions ◽  
Physical Properties ◽  
Dielectric Constants ◽  
Water Molecules ◽  
Absorption Coefficients ◽  
Basic Substance ◽  
High Dilutions

For the first time, an ultra-high-sensitivity method for measuring radio-thermal radiation was developed and used in practice in order to establish the difference in the physical properties of aqueous solutions of substances in the millimeter region of the spectrum. The method is used to study the dynamics of the dielectric properties of aqueous solutions depending on the composition of the base substance and its concentration. The dynamics of dielectric properties establishes a one-to-one correspondence between the number and concentration of ions of the dissolved basic substance contained in water and the number of water molecules involved in cooperative interaction, which gives a consistent microscopic picture of ion-water cooperative interactions in the studied aqueous solutions of K2SO4 and Cs2SO4. The density of water molecules perturbed by the ions of the base substance contained in the hydration shell at normal concentrations is proportional to the number of ions, while the transition to weaker solutions leads to the creation of multilayer hydration shells. This means that the number of perturbed water molecules, depending on the number of ions, increases according to a law different from linear. In accordance with the experimental data, the values of the absorption coefficients of aqueous solutions were determined in a wide range of concentrations for alkali metal sulfates. It is noted that alkali metal sulfates have physical properties that generalize the dynamics of dielectric constants depending on the concentration of the base substance. A monotonic increase in the values of the absorption coefficients of solutions with a decrease in the concentration of basic substances in the region of high dilutions was established with individual dynamics for each basic substance, reflecting the total hydration changes in salt solutions. Research has shown that the proposed method for measuring radio-thermal radiation fixes a significant difference in the values of the dielectric constants of aqueous solutions at high dilutions from their values for water.

Dispiroacridine-indacenobisthiophenes positional isomers: Impact of the bridge on the physicochemical properties

2021 ◽  
Author(s):  
Jean-David Peltier ◽  
Benoît Heinrich ◽  
Bertrand Donnio ◽  
Olzhas A. Ibraikulov ◽  
Thomas Heiser ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Physicochemical Properties ◽  
Physical Properties ◽  
Charge Transport ◽  
Energy Levels ◽  
Molecular Organization ◽  
Positional Isomers ◽  
Lumo Energy ◽  
Positional Isomerism ◽  
Homo Lumo

We report the influence of positional isomerism on the electronic (electrochemical HOMO/LUMO energy levels), photophysical and physical properties (molecular organization, crys¬¬tallinity and phase transitions) and charge transport properties of dispiroacridine-in¬da¬ce¬no¬bis¬thio¬phene...

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