Study of Relative Metallic Character of Noble Metals Cu, Ag and Au at Normal Temperatures

2021 ◽  
Vol 1019 ◽  
pp. 174-178
Author(s):  
Ramesh Kumar ◽  
Priti Kumari ◽  
Kumar Saurav ◽  
Purushottam Poddar ◽  
Vijay Kumar Verma

The relative metallic character of noble metals, Cu, Ag & Au has been suggested by their physical and chemical properties. Their position in the metallic series is in the neighborhood of that of Li, Mg and Zn. These Metals are inferior of Li, Mg, Zn, Fe, Co and Ni in metallic character. Li, Mg, Zn, Fe, Co and Ni are inferior to Na, K, Rb, Cs, Ca, Ba and Sr. The noble metals have simple metallic character in physical properties at normal temperatures.

Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1476
Author(s):  
Ana Cristina Ferrão ◽  
Raquel P. F. Guiné ◽  
Elsa Ramalhosa ◽  
Arminda Lopes ◽  
Cláudia Rodrigues ◽  
...  

Hazelnuts are one of the most appreciated nuts worldwide due to their unique organoleptic and nutritional characteristics. The present work intended to analyse several physical and chemical properties of different hazelnut varieties grown in Portugal, namely Tonda de Giffoni, Grada de Viseu, Segorbe, Longa de Espanha, Butler, Gunslebert, and Negreta. In general, the results revealed statistically significant differences between the varieties under study. The Gunslebert had more elongated hazelnuts and with heavier shelled fruits, while the kernels of the Grada de Viseu revealed to be heavier. Grada de Viseu was harder in the shell, Gunslebert had a harder core, and Segorbe was more resistant to fracture. Fat was the more representative component for all varieties and in some cases the values of moisture and water activity were over the recommended amount (≥0.62). Tonda de Giffoni was the variety with the highest induction time, indicating the highest oxidation stability. Moreover, discriminant analysis revealed that the variables more important to distinguish the varieties were protein (λ = 0.007) and water activity (λ = 0.010). The results of this study help to better understand the differences between some hazelnut varieties that are cultivated in Portugal, which gives important hints for all players in the hazelnut sector.


2021 ◽  
pp. 1-10
Author(s):  
Anshu Siwach ◽  
Siddhartha Kaushal ◽  
Ratul Baishya

Abstract Mosses are one of the most important and dominant plant communities, especially in the temperate biome, and play a significant role in ecosystem function and dynamics. They influence the water, energy and element cycle due to their unique ecology and physiology. The present study was undertaken in three different temperate forest sites in the Garhwal Himalayas, viz., Triyuginarayan (Kedarnath Wildlife Sanctuary (KWLS)), Chakrata, and Kanasar forest range. The study was focused on understanding the influence of mosses on soil physical properties and nutrient availability. Different physico-chemical properties were analysed under two different substrata, that is, with and without moss cover in two different seasons, viz., monsoon and winter. We observed mosses to influence and alter the physical properties and nutrient status of soil in both seasons. All soil physical and chemical properties, except magnesium, showed significant difference within the substrates, among all the sites and across the two seasons. Besides the soil characteristics underneath the moss vegetation, the study also highlights the diversity of mosses found in the area. Mosses appear to create high nutrient microsites via a high rate of organic matter accumulation and retain nutrients for longer periods thus, maintaining ecosystem stability.


Soil Research ◽  
1991 ◽  
Vol 29 (2) ◽  
pp. 263 ◽  
Author(s):  
PP Cavanagh ◽  
AJ Koppi ◽  
AB Mcbratney

Reducing cultivation may improve many soil physical and chemical properties of a red-brown earth. A trial was set up in 1986 on a red-brown earth near Forbes, N.S.W., comparing direct-drilling and conventional-cultivation crop establishment techniques. The surface soil (0-100 mm) was sampled at the end of the third year and assessed for macropore structure, infiltration characteristics, bulk density, pH, electrolytic conductivity, organic carbon and total nitrogen content. Cultivation degraded some desirable soil physical properties as indicated by data obtained from image analysis and infiltration. Bulk density did not mirror differences in macroporosity. Organic carbon, total nitrogen and electrolytic conductivity levels were higher in direct-drilled soil in comparison to conventionally tilled soil. It ib concluded that the improvement of soil chemical and physical properties afforded by a reduction in tillage would lead to an increase in soil water infiltration rate and storage.


Soil Research ◽  
1991 ◽  
Vol 29 (2) ◽  
pp. 263
Author(s):  
PP Cavanagh ◽  
AJ Koppi ◽  
AB Mcbratney

Reducing cultivation may improve many soil physical and chemical properties of a red-brown earth. A trial was set up in 1986 on a red-brown earth near Forbes, N.S.W., comparing direct-drilling and conventional-cultivation crop establishment techniques. The surface soil (0-100 mm) was sampled at the end of the third year and assessed for macropore structure, infiltration characteristics, bulk density, pH, electrolytic conductivity, organic carbon and total nitrogen content. Cultivation degraded some desirable soil physical properties as indicated by data obtained from image analysis and infiltration. Bulk density did not mirror differences in macroporosity. Organic carbon, total nitrogen and electrolytic conductivity levels were higher in direct-drilled soil in comparison to conventionally tilled soil. It ib concluded that the improvement of soil chemical and physical properties afforded by a reduction in tillage would lead to an increase in soil water infiltration rate and storage.


Author(s):  
Mokhtaria Ould Kada ◽  
Allel Mokaddem ◽  
Bendouma Doumi ◽  
Mohamed Berber ◽  
Lahouari Temimi ◽  
...  

Background: In this paper, we have studied the improvement of the physical and chemical properties of the fiber-matrix interface of a Biocomposite based on the copolymer polylactic acid (PLA). Methodology: We have developed an analytical model using a genetic approach to locate the interface damage under the effect of mechanical stress, temperature and humidity. Our simulation is based on Weibull's probabilistic approach and the law of water diffusion in polymer matrix, the diffusion is generated by Fick's law. Results: Our results show that the interface of Biocomposite (Starch-PLA) is the most resistant to the different constraints applied and that the physical and chemical properties of this material are much more improved compared to other materials studied by the same genetic model. Conclusion: Our calculations coincide perfectly with the conclusions of Antoine et al. who determined that natural fibers improve the physical properties of composite materials.


1950 ◽  
Vol 23 (1) ◽  
pp. 266-280 ◽  
Author(s):  
W. Murray Gall

Abstract Hard rubber, frequently called ebonite, is a material which has many desirable physical and chemical properties. The relatively new plastics industry has offered stiff competition, yet it is reasonably safe to say that, for certain applications, nothing else can be substituted for hard rubber and still maintain its unique properties. One of the principal qualities of this material is its finished appearance. When a high-grade ebonite compound is properly processed, it can be given a high lustrous finish which sets it apart from similar materials for beauty and richness. The highest grade of hard rubber is a compound containing only rubber and sulfur. It is in this type of compound that maximum physical properties and highest luster are found.


BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 5975-5998
Author(s):  
Faustino Ruiz-Aquino ◽  
Lizbeth Luna-Bautista ◽  
Aremi E. Luna-Bautista ◽  
Wenceslao Santiago-García ◽  
Luis F. Pintor-Ibarra ◽  
...  

The anatomical characteristics and the physical and chemical properties of wood of Quercus macdougallii Martínez are presented for the first time. Q. macdougallii Martínez is an endemic species of the Sierra Juarez of Oaxaca. The microscopic characteristics were described in preparations of typical cuts and dissociated material. The physical properties were evaluated according to the ASTM D 143-94 standard in sapwood and heartwood specimens. The measurable elements and physical properties were classified according to the mean. With the measurable elements, the paper pulp quality index was determined. In sapwood and heartwood, the basic chemical composition was determined. The wood of Q. macdougallii presented a pronounced grain, a thick texture, and a straight thread. Fibers, fibrotracheids, uniseriate, multiseriate, and aggregate rays were found. Basic density 0.55 g cm-3 in sapwood and 0.61 g cm-3 in heartwood is classified as moderately heavy and heavy, respectively. The saturation point of the fiber is classified as high. Based on its physical properties, Q. macdougallii wood can be used in the manufacture of furniture, veneer, floors, tool handles, and construction. Based on the pulp quality indices and chemical composition, this wood could be used to obtain cellulose pulp for paper.


1967 ◽  
Vol 182 (1) ◽  
pp. 109-134 ◽  
Author(s):  
A. C. M. Wilson

Major items of C.E.G.B. power plant are now being designed to operate at high steam temperatures and hydraulic pressures. In consequence, the risk of fires due to leaking petroleum lubricants is increasing. Suitable fire-resistant (f.r.) fluids are therefore desirable. Some of these have, however, given rise to difficulties in service due to changes in their physical and chemical properties. The physical properties of non-aqueous synthetic f.r. fluids (i.e. phosphate esters and chlorinated diphenyls) have been surveyed, and their chemical stability and anti-corrosion properties determined. Whilst the physical properties of the phosphate esters are better than those of the chlorinated diphenyls the chemical stability and corrosion properties are much worse.


2012 ◽  
Vol 9 (74) ◽  
pp. 2299-2308 ◽  
Author(s):  
Fujia Chen ◽  
David Porter ◽  
Fritz Vollrath

Silkworm cocoons have evolved a wide range of different structures and combinations of physical and chemical properties in order to cope with different threats and environmental conditions. We present our observations and measurements on 25 diverse types of cocoons in a first attempt to correlate physical properties with the structure and morphology of the cocoons. These two architectural parameters appear to be far more important than the material properties of the silk fibres themselves. We consider tensile and compressive mechanical properties and gas permeation of the cocoon walls, and in each case identify mechanisms or models that relate these properties to cocoon structure, usually based upon non-woven fibre composites. These properties are of relevance also for synthetic non-woven composite materials and our studies will help formulate bio-inspired design principles for new materials.


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