scholarly journals Tailoring the Size and Shape—New Path for Ammonium Metavanadate Synthesis

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3446
Author(s):  
Marta Prześniak-Welenc ◽  
Małgorzata Nadolska ◽  
Barbara Kościelska ◽  
Kamila Sadowska
Keyword(s):  
Room Temperature ◽  
Chemical Properties ◽  
Ph Control ◽  
Ammonium Metavanadate ◽  
Step Procedure ◽  
One Step ◽  
The One ◽  
Physical And Chemical ◽  
Ammonium Compounds ◽  
And Chemical Properties

Ammonium metavanadate, NH4VO3, plays an important role in the preparation of vanadium oxides and other ammonium compounds, such as NH4V3O8, (NH4)2V3O8, and NH4V4O10, which were found to possess interesting electrochemical properties. In this work, a new route for the synthesis of NH4VO3 is proposed by mixing an organic ammonium salt and V2O5 in a suitable solvent. The one-step procedure is carried out at room temperature. Additionally, the need for pH control and use of oxidants necessary in known methods is eliminated. The mechanism of the NH4VO3 formation is explained. It is presented that it is possible to tailor the morphology and size of the obtained NH4VO3 crystals, depending on the combination of reagents. Nano- and microcrystals of NH4VO3 are obtained and used as precursors in the hydrothermal synthesis of higher ammonium vanadates. It is proven that the size of the precursor particles can significantly affect the physical and chemical properties of the resulting products.

Address of the President Lord Todd, O. M. at the Anniversary Meeting, 1 December 1980

1980 ◽  
Vol 211 (1182) ◽  
pp. 1-13 ◽  
Keyword(s):  
Usnic Acid ◽  
Chemical Properties ◽  
Wide Range ◽  
One Step ◽  
Oxidative Processes ◽  
The One ◽  
Physical And Chemical ◽  
Biosynthetic Studies ◽  
And Chemical Properties

The Copley Medal is awarded to Sir Derek Barton, F. R. S. Among Sir Derek Barton's many distinguished contributions to organic chemistry, outstanding is his conception and development of conformational analysis, which represents the most important advance in this century in the understanding of the stereochemistry of organic compounds, and for which he received a Nobel Prize in 1969. Originally devised for cyclohexane derivatives, the concept was rapidly extended to other ring systems, and is of major importance in interpretation of the physical and chemical properties of a wide range of natural products. Sir Derek has also contributed greatly to the understanding of biosynthesis, and in many cases demonstrated the validity of his hypotheses by labelling experiments in vivo . In particular, his ideas on the nature of phenolic coupling, involving one-electron oxidative processes, formed the basis of a very large number of successful biosynthetic studies, especially in the alkaloid field. He has also applied his ideas to the simulation of natural biosynthetic sequences, the one-step synthesis of the complex usnic acid from a simple monocyclic precursor providing one of the most striking examples.

New Condensation Products of Rubber Hydrocarbons by the Aid of Benzyl Chloride

1932 ◽  
Vol 5 (2) ◽  
pp. 110-116
Author(s):  
F. Kirchhof
Keyword(s):  
Aluminum Chloride ◽  
Benzyl Chloride ◽  
Condensation Product ◽  
Chemical Properties ◽  
Metal Chlorides ◽  
Condensation Products ◽  
New Type ◽  
The One ◽  
Physical And Chemical ◽  
And Chemical Properties

Abstract The application of the long-known Friedel-Crafts reaction to rubber hydrocarbons led to a new type of condensation products which may be called provisionally aral cyclorubbers (“benzylidene rubbers”), since their benzylidene groups are probably condensed with the polyprene skeleton to cyclic systems. It would not have been foreseen without further work that rubber would form this type of condensation product with aral halides in the presence of aluminum chloride, since on the one hand benzyl chloride is known to form, by the action of aluminum chloride in the Friedel-Crafts reaction, an amorphous, apparently high molecular hydrocarbon of the empirical composition (C7H6)x, and on the other hand rubber in solution is transformed by the metal chlorides, especially aluminum chloride, into amorphous polycyclorubbers. Under definite conditions of condensation with aluminum chloride aral groups are combined with the skeleton of the rubber hydrocarbon with the formation of white to yellowish amorphous bodies which contain, in addition to a small proportion of organically combined chlorine, only carbon and hydrogen, and are therefore to be regarded as hydrocarbons. In their physical and chemical properties these substances resemble the already known amorphous substance of the empirical formula (C7H6)x, which doubtless is polybenzylidene, probably hexabenzylidene.

Physical and Chemical Properties of Silicon Dioxide Film Deposited by New Process

1987 ◽  
Vol 105 ◽  
Author(s):  
Takuji Goda ◽  
Hirotsugu Nagayama ◽  
Akihiro Hishinuma ◽  
Hideo Kawahara
Keyword(s):  
Silicon Dioxide ◽  
Room Temperature ◽  
Etching Rate ◽  
Chemical Properties ◽  
Industrial Area ◽  
Physical And Chemical Properties ◽  
Silicon Dioxide Film ◽  
Wide Range ◽  
Physical And Chemical ◽  
And Chemical Properties

AbstractA new coating process of silicon dioxide (SiO2) “LPD” process, has been developed recently. Silicon dioxide (SiO2) film can be deposited on any substrate at the room temperature by immersing in hexafluorosilicic acid (H2SiF6).In this study, physical and chemical properties of the “LPD- SiO2” film were investigated by using XPS, IR, ellipsometry, and etch rate measurement. The properties of this film deposited at the room temperature were almost the same as those of plasma CVD. The “LPD-SiO2” film without annealing was contained traces of F and OH. However, by annealing, F and OH were rapidly evaporated from the film and the film was getting densified.As the “LPD-SiO2” film deposited at the room temperature showed very good results of chemical etching rate and of step coverage, it is expected that it is possible to use this “LPD- SiO2” film in the wide range of industrial area.

scholarly journals Effects of Continuous Cropping of Dictyophora on Soil Physical and Chemical Properties, Microbial Biomass and Enzyme Activity

2021 ◽  
Vol 8 (7) ◽  
pp. 214-220
Author(s):  
Long Tong ◽  
◽  
Hongyan Li ◽  
Xiaoming Liu ◽  
Bin Li ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Ph Value ◽  
Chemical Properties ◽  
Available Phosphorus ◽  
Continuous Cropping ◽  
Physical And Chemical Properties ◽  
Factors Affecting ◽  
The One ◽  
Physical And Chemical ◽  
And Chemical Properties

The continuous obstacle of Dictyophora indusiata has become the one of the main factors affecting the healthy development of D. indusiata industry. In order to study the effects of continuous cropping of D. indusiata on the soil environment, four treatments were used in this study: no planted (CK), planted for 1 years (1Y), continuous cropping for 2 years (2Y) and continuous cropping for 3 years (3Y), to determined of the yield of D. indusiata, soil physical and chemical properties, microbial content and enzyme activity. The results showed that the yield and soil pH value decreased with the increase of continuous cropping years, and the contents of organic matter, total nitrogen, total phosphorus and total potassium, C/N and C/P also increased with the increase of continuous cropping years. Soil availability decreased with the increase of continuous cropping years, the content of alkaline nitrogen, available phosphorus and available potassium decreased by 12.25%, 28.91% and 24.86% at 3Y compared with 1Y, respectively. The biomass of bacteria, actinomycetes and fungi and the total amount of microorganism in soil increased at 1Y compared with CK, but with the increase of continuous cropping years, the biomass of bacteria and actinomycetes and the total amount of microorganism decreased significantly, while the biomass of fungi increased significantly; the continuous cropping of D. indusiata also decreased the value of bacteria/fungi in soil. The enzyme activities of the soil were higher than those of the unplanted plots, however, the activities of urease, catalase, peroxidase, sucrase, phosphatase and protease decreased with the increase of continuous cropping years. In a word, with the increase of continuous cropping, the acidity of rhizosphere soil increased, the availability of soil nutrients and the activity of soil enzymes decreased, the biomass of soil microorganisms, bacteria and actinomycetes decreased. However, the increase of fungal biomass led to the decline of soil texture.

Experimental Study on the Heat Transfer in the Al Powder

2009 ◽  
Vol 83-86 ◽  
pp. 953-958
Author(s):  
Ching Yen Ho ◽  
Yu Hsiang Tsai ◽  
Mao Yu Wen
Keyword(s):  
Heat Transfer ◽  
Thermal Conduction ◽  
Room Temperature ◽  
Bulk Material ◽  
Chemical Properties ◽  
Bulk Materials ◽  
Processing Technologies ◽  
Insulating Material ◽  
Physical And Chemical ◽  
And Chemical Properties

Nanometer-sized particles possess characteristic physical and chemical properties different from those of bulk materials due to an increase in surface-to-volume ratios as well as of confinement of electrons, excitons, and photons into small volumes. Therefore it is worthwhile to discuss the thermal behaviours of powders constituted by nanometer-sized particles. The heat transfer in the powder composed of nanoparticles is experimentally investigated in this paper. The understanding for thermal properties of the powder is advantageous to the advancement of the processing technologies such as laser cladding, laser sintering, powder metallurgy and its other applications. The powder is wrapped up in the slender tube made of insulating material. One end of the slender tube filled with powder is maintained at temperature 0°C and the other end is kept at room temperature. The temperature histories at two different locations in the slender tube are recorded using thermal couples. The results show that the thermal diffusivity in the powder composed of nanoparticles is larger than that in bulk material. The pressure on the Al powders enhances the rate of heat transport due to the increase of contact area for thermal conduction.

Bulrush-Like Double Perovskite: Synthesis, Tunneling Magnetoresistance, and Magnetocaloric Effects

2008 ◽  
Vol 8 (6) ◽  
pp. 2793-2810 ◽  
Author(s):  
W. Zhong ◽  
N. J. Tang ◽  
C. T. Au ◽  
Y. W. Du
Keyword(s):  
Room Temperature ◽  
Recent Observation ◽  
Chemical Properties ◽  
Double Perovskite ◽  
Tunneling Magnetoresistance ◽  
Double Perovskites ◽  
New Approach ◽  
Half Metallic ◽  
Physical And Chemical ◽  
And Chemical Properties

The recent observation of room temperature tunneling magnetoresistance (TMR) in half-metallic A2FeMoO6 (A = Ca, Sr, Ba) double perovskites, and their importance to the emerging field of spintronics has led to considerable effort being dedicated to detailed investigations of the physical and chemical properties of these materials. This article will present an review of our recent investigations covering the synthesis, structures, magnetic and transport properties of "bulrush-like" A2FeMoO6 (A = Sr, Ba). Utilizing the high shape anisotropy as well as the reactivity of A2FeMoO6 to water and a sonochemical technique, we managed to manipulate the properties of grain boundary barriers, and thus put forward a new approach for the enhancement of room temperature TMR. The magnetocaloric effects of A2FeMoO6 double perovskites will also be discussed.

Preparation of Lignopolyols by Chemical Modification of Kraft Lignin from Oil Palm Lignocellulosic Waste

2015 ◽  
Vol 1107 ◽  
pp. 137-141
Author(s):  
Abbas Hasan Faris ◽  
Afidah Abdul Rahim ◽  
Mohamad Nasir Mohamad Ibrahim
Keyword(s):  
Oil Palm ◽  
Room Temperature ◽  
Chemical Properties ◽  
Kraft Lignin ◽  
Kraft Pulping ◽  
Lignocellulosic Waste ◽  
Alkaline Conditions ◽  
Physical And Chemical ◽  
Tga And Dsc ◽  
And Chemical Properties

The main objective of this research was to describe the thermal and chemical characteristics of lignopolyols. Lignin was extracted from oil palm empty fruit bunch after kraft pulping process. Oxypropylation reaction was achieved by reacting kraft lignin with propylene oxide under alkaline conditions at room temperature. The physical and chemical properties of lignopolyols were evaluated by FTIR, NMR, GPC, TGA, and DSC. Lignopolyol exhibited higher chemical activity than kraft lignin. The polyols used as precursors in biomass-based wood adhesives preparation demonstrated promising results. Keywords: kraft lignin, lignopolyol, oxypropylation, NMR spectroscopy, DSC

scholarly journals Influence of the Addition of Calcium Hydroxide Powder on Some Physical and Chemical Properties of the Sealer MTA Fillapex

2012 ◽  
Vol 3 (2) ◽  
pp. 180-183
Author(s):  
Marcelo Ferrarezi de Andrade ◽  
Renato de Toledo Leonardo ◽  
Edson Alves de Campos ◽  
Milton Carlos Kuga ◽  
Marco Antonio Hungaro Duarte ◽  
...  
Keyword(s):  
Calcium Hydroxide ◽  
Calcium Release ◽  
Ph Value ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Ph Values ◽  
The One ◽  
Physical And Chemical ◽  
The Impact ◽  
And Chemical Properties

ABSTRACT Objective This study evaluated the flow, pH and calcium release of MTA Fillapex (G1) or Fillapex plus 10% in weight of calcium hydroxide powder (G2), compared to AH Plus (G3) and Sealapex (G4). Materials and methods The flow test was performed according to ISO 6876:2001 requirements. The sealers were placed into plastic tubes and immersed in deionized water. After 24 hours, 7, 14 and 28 days, the water of each tube was removed and tested to evaluate the pH values and the level of released calcium. Calcium release values were analyzed statistically by Kruskal Wallis and Dunn tests and pH values analyzed by ANOVA and Tukey tests (α = 5%). Results G1 presented higher flow among all sealers. The addition of 10% calcium hydroxide into MTA Fillapex reduced the flow (p < 0.05) but, in a level, that is lower than the one recommended for ISO norms. G2 and G4 presented pH values and calcium release higher than G3 (p < 0.05) in all periods. G1 presented pH value higher than G3 (p < 0.05), except in 7 days period (p > 0.05). G4 presented higher pH values than G1 and G2, but the calcium release was similar for all periods (p > 0.05). G3 presented lower calcium release among all groups (p < 0.05). Conclusion The addition of 10% calcium hydroxide in MTA Fillapex caused reduction in flow and no negative interference in pH and/or calcium release. However, the obtained flow is different from ISO requirements. Clinical relevance MTA Fillapex presents levels of flow above the ISO norms. The addition of calcium hydroxide is a suggestion for solving this problem, but the impact of these procedures should be carefully evaluated. How to cite this article Keine KC, Guiotti FA, Leonardo RT, Kuga MC, Duarte MAH, de Campos EA, de Andrade MF. Influence of the Addition of Calcium Hydroxide Powder on Some Physical and Chemical Properties of the Sealer MTA Fillapex. World J Dent 2012;3(2):180-183.

scholarly journals Marine-Derived Collagen as Biomaterials for Human Health

2021 ◽  
Vol 8 ◽  
Author(s):  
Ning Xu ◽  
Xue-Liang Peng ◽  
Hao-Ru Li ◽  
Jia-Xuan Liu ◽  
Ji-Si-Yu Cheng ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Chemical Properties ◽  
Extraction Methods ◽  
Marine Organisms ◽  
The Other ◽  
Physical And Chemical Properties ◽  
Fish Scales ◽  
The One ◽  
Physical And Chemical ◽  
And Chemical Properties

Collagen is a kind of biocompatible protein material, which is widely used in medical tissue engineering, drug delivery, cosmetics, food and other fields. Because of its wide source, low extraction cost and good physical and chemical properties, it has attracted the attention of many researchers in recent years. However, the application of collagen derived from terrestrial organisms is limited due to the existence of diseases, religious beliefs and other problems. Therefore, exploring a wider range of sources of collagen has become one of the main topics for researchers. Marine-derived collagen (MDC) stands out because it comes from a variety of sources and avoids issues such as religion. On the one hand, this paper summarized the sources, extraction methods and characteristics of MDC, and on the other hand, it summarized the application of MDC in the above fields. And on the basis of the review, we found that MDC can not only be extracted from marine organisms, but also from the wastes of some marine organisms, such as fish scales. This makes further use of seafood resources and increases the application prospect of MDC.

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