Search results

Filters

  • Journals
  • Authors
  • Keywords
  • Date
  • Type

Search results

Number of results: 36
items per page: 25 50 75
Sort by:
Download PDF Download RIS Download Bibtex

Abstract

The article describes the impact of germanium on the course of surface phenomena in casting alloys of silver used in gold smithing. The aim of this works is to describe the assessment of resulting alloys, comparing the area of raw castings and the impact of the addition content of the alloy on the hardness of the samples. The evaluation also was subject to corrosion resistance of giving a comparison of their use in relations to traditional silver alloys.
Go to article

Authors and Affiliations

M. Jesiotr
W. Trzaskowski
D. Trochimiak
P. Nawrocki
K. Łukasik
D. Myszka
Download PDF Download RIS Download Bibtex

Abstract

Three plants extracts were used for biosynthesis of Ag nanoparticles (AgNPs). AgNPs nucleation process requires effective reduction agents which secure Ag+ to Ag0 reduction and also stabilizing/capping agents. The UV-vis and TEM observation revealed that the best results were obtained by R. officinalis leaf extract. The strong SPR band peak appeared at the wavelength 418 nm. Synthetized AgNPs were globular, fine (~20 nm), uniform and stabile throughout the experiment. A rapid rate of AgNPs synthesis was also significant and economically advantageous factor. Fine (10-20 nm) and globular nanoparticles were synthetized also by U. dioica leaf extract, but the stability of nanoparticles was not permanent. Despite V. vitis-idaea fruit extract contains a lot of reducing agents, UV-vis did not confirm the presence of AgNPs in solution. Synthetized Ag particles were very unstable, Ag particles agglomerated very fast and clearly indicated sediment was formed.

Go to article

Authors and Affiliations

O. Velgosová
A. Mražíková
L. Veselovský
J. Willner
A. Fornalczyk
Download PDF Download RIS Download Bibtex

Abstract

For the reliable applications of silver nanowires, AgNW, which is used as a conductive transparent film in electronic devices, the isothermal degradation behaviors of AgNW films with and without overcoating were investigated. Accelerated isothermal degradation was performed as a function of temperature, time, and atmosphere. Electrical resistance and optical transmittance were measured and correlated with the microstructural damages, such as formation of oxide particles and fragmentations of AgNW, which were quantitatively determined from the scanning electron micrographs. The overcoating retarded the formation of oxide particles and subsequent fragmentations as well as resulting degradation in electrical resistance without affecting the optical transmittance.

Go to article

Authors and Affiliations

Jae-Yeon Kim
Hye-Young Kim
Hyun-Su Kim
Ki-Tae Yoo
Won-Jon Yang
Jai-Won Byeon
Download PDF Download RIS Download Bibtex

Abstract

Silver nanoparticles (AgNPs) are widely used in numerous industries and areas of daily life, mainly as antimicrobial agents. The particles size is very important, but still not suffi ciently recognized parameter infl uencing the toxicity of nanosilver. The aim of this study was to investigate the cytotoxic effects of AgNPs with different particle size (~ 10, 40 and 100 nm). The study was conducted on both reproductive and pulmonary cells (CHO-9, 15P-1 and RAW264.7). We tested the effects of AgNPs on cell viability, cell membrane integrity, mitochondrial metabolic activity, lipid peroxidation, total oxidative and antioxidative status of cells and oxidative DNA damage. All kinds of AgNPs showed strong cytotoxic activity at low concentrations (2÷13 μg/ml), and caused an overproduction of reactive oxygen species (ROS) at concentrations lower than cytotoxic ones. The ROS being formed in the cells induced oxidative damage of DNA in alkaline comet assay. The most toxic was AgNPs<10 nm. The results indicate that the silver nanoparticles, especially less than 10 nm, may be harmful to the organisms. Therefore, risk should be considered when using nanosilver preparations and provide appropriate protective measures when they are applied.

Go to article

Authors and Affiliations

Lidia Zapór
Download PDF Download RIS Download Bibtex

Abstract

In August 2016, tomato plants grown during a hot, wet summer with heavy soil flooding, displaying symptoms of wilting, dead plant, root rot with crown and stem rot, at Beni Suef and Fayoum governorates were examined. A number of 16 fungal isolates were isolated from tomato plants displaying the above symptoms. These isolates were classified as belonging to six species, namely: Alternaria solani, Chaetomium globosum, Fusarium solani, Fusarium oxysporum, Pythium spp. and Rhizoctonia solani. Isolates of Pythium spp. were prevalent and were found to be more pathogenic than the other fungal isolates. This species causes damping-off, root rot, sudden death, stem rot and fruit rot. The pathogen was identified as Pythium aphanidermatum based on morphological, cultural, and molecular characteristics. Biogenic silver nanoparticles (AgNPs) were produced using the F. oxysporum strain and characterized by transmission electron microscopy (TEM). The size of these spherical particles ranged from 10 to 30 nm. In vitro, biogenic AgNPs showed antifungal activity against P. aphanidermatum. In greenhouse and field experiments, AgNPs treatment significantly reduced the incidence of dead tomato plants due to root rot caused by P. aphanidermatum compared to the control. All of the investigated treatments were effective and the treatment of root dipping plus soil drenching was the most effective. To the best of our knowledge, this study describes P. aphanidermatum on tomato in Egypt for the first time. Also, biogenic AgNPs could be used for controlling root rot disease caused by this pathogen.
Go to article

Authors and Affiliations

Ibrahim Elshahawy
Hesham Mohamed Abouelnasr
Sirag Mohamed Lashin
Osama Mohamed Darwesh
Download PDF Download RIS Download Bibtex

Abstract

Layers of silver particles are used in the studies on pathophysiology and treatment of diseases, both in pre-clinical and clinical conditions. Silver layers can be formed using different techniques and on different substrates. Deposition by magnetron sputtering on glass beads was used in this study. Silver absorption by the body was estimated by calculating the difference in thickness of the silver nanolayer deposited on a bead and measured before and after application of the bead in an animal model of gastrointestinal inflammation. Recommendations for the minimal thickness of silver nanolayer deposited on glass beads were worked out for further studies.

Go to article

Authors and Affiliations

Krzysztof Siczek
Wojciech Pawlak
Hubert Zatorski
Jakub Fichna
Download PDF Download RIS Download Bibtex

Abstract

Silver coatings have a very high reflection ability. To avoid their darkening from the hydrogen sulphide in the air, a thin layer of heat-resistant colorless lacquer is applied to the coatings. Silver plating is mainly used in jewelery, optics, electronics and electrical engineering. Depending on their application the thickness of the layer may vary from 2 to 24 μm. It can be done in several ways: chemical, electrochemical, contact, etc. The most common way of silver plating is the electrochemical deposition using cyanide and non-cyanide electrolytes. The cyanide electrolytes produce light, fine crystalline, dense and plastic coatings upon silver-plating. Usually silver coatings are applied with copper or nickel intermediate layer. In order to improve the de-oxidation of the aluminum surface new chemical treatment in acid – alkaline solution was applied. Our previous research shows that the presence of diamond nanoparticles in the electrolyte increase the metal deposition. Samples were prepared from electrolyte containing 10 g/l diamond nanoparticles. Their properties were compared to the properties of reference samples. The diamonds were obtained by detonation synthesis. The aim of this study is to obtain electrochemically deposited silver layer with high density, adhesion and electric conductivity on aluminum alloys substrate. The coatingwas directly plated without intermediate layer. Non-cyanide electrolyte composition and electrochemical parameters were determined in order to produce Ag coatings on Al alloy substrate without intermediate layer. The coating is with good adhesion, density and thickness of 14-23 μm.

Go to article

Authors and Affiliations

R. Valov
V. Petkov
S. Valkano
Download PDF Download RIS Download Bibtex

Abstract

Prolonged exposure to UV radiation, and ever-increasing life expectancy, mean that an increasing proportion of the population suffers from clouding of the intraocular lens. Nowadays, the performance of intraocular implantation procedures is commonplace. Unfortunately, with the increasing number of operations, the number of postoperative complications is also increasing. One way to avoid complications may be to use an intraocular implant that has been immersed in a solution containing silver nanoparticles. As part of the study, four selected intraocular implants – that are available on the ophthalmic market – were tested. In order to investigate the effect of silver particles on the optical properties of the implants, tests were carried out using a UV-VIS spectrophotometer. Two series of implants were tested: before and after immersion in a silver solution. The implants were immersed for a period of 7 days. It was found that the presence of silver particles does not have a negative impact on the translucency of the implants.
Go to article

Authors and Affiliations

K. Jeż
1
ORCID: ORCID
M. Gacek
1
ORCID: ORCID
M. Nabiałek
1
ORCID: ORCID
L. Toth
2
ORCID: ORCID
M. Pike-Biegunski
3

  1. Czestochowa University of Technology, Faculty of Production Engineering and Materials Technology, Department of Physics, 19 Armii Krajowej Str., 42-200 Częstochowa, Poland
  2. Óbuda University, Bánki Donát Faculty of Mechanical and Safety Engineering, Material Science Department, 1081, Népszínház 8, Budapest, Hungary
  3. Nano Koloid sp. z o. o, Hoża 62/37, 00-682 Warszawa, Poland
Download PDF Download RIS Download Bibtex

Abstract

This article describes silver specimens of the size of tenths to a few millimetres, found in small pegmatites and quartz veinlets of the porphyritic granitoid area in 22 sites in the eastern part of the Variscan granitoid Karkonosze pluton, from 20 of which native silver occurrences were previously not known. The sites are scattered on the whole surface of the granitoid. The native silver occurred in wire, rod, platy, dendritic, anhedral granular and euhedral cubic and octahedral habits; in some specimens twins and fenster faces were also found. Associated with native silver small amounts of acanthite crystallized commonly, sometimes apparently formed by sulphur diffusion into silver. Inclusions of native gold, electrum, galena, chalcopyrite and pyrite occurred in the native silver. The parent fluids of the specimens were epithermal, because the homogenization temperature (Th) of inclusions in quartz, calcite and cleavelandite that were the host minerals of the native silver was generally 91–165ºC and for individual samples the Th range was 4–11ºC. The total salinity of the fluid was 2.4–7.2 wt. % with Na and Ca (hydro)carbonates as the main dissolved components and admixtures of K, Mg, Fe, Al, S, Cl and F. The parent granitoid contains Ag in trace amounts (0.034–0.056 ppm) and was probably the source of this element for the crystals of native silver. Migration of Ag was made easier by the presence of fluoride ions in fluids.
Go to article

Authors and Affiliations

Andrzej Kozłowski
1
Witold Matyszczak
1

  1. University of Warsaw, Faculty of Geology, Żwirki i Wigury 93, 02-089 Warszawa, Poland
Download PDF Download RIS Download Bibtex

Abstract

The publication presents experimental verification of a mathematical model of silver nanowire (AgNWs) fabrication in a continuous flow process in a helical tubular reactor. Silver nanowires were synthesised with a polyol process, with ethylene glycol as the reductant of the nanomaterial precursor and solvent of the reactants. The observed average diameters and lengths of AgNWs were 98-226 nm and 5-45 μm, respectively. The experimental conversions of the precursor were 0.71-0.90. A comparison of calculated and measured conversions for the investigated range of residence times and temperatures showed that the observed error was less than 20%.
Go to article

Authors and Affiliations

Grzegorz Dzido
1
ORCID: ORCID
Muhammad Omer Farooq
2
ORCID: ORCID
Aleksandra Smolska
2
ORCID: ORCID

  1. Silesian University of Technology, Department of Chemical Engineering and Process Design,Strzody 7, 44-100 Gliwice, Poland
  2. Silesian University of Technology, Doctoral School, Akademicka 2A, 44-100 Gliwice, Poland
Download PDF Download RIS Download Bibtex

Abstract

Недотыкомка is a symbol-word in the Russian literature of the Silver Age, meaning ubiquitous evil, according to the modernist world view, constituting the nature of existence. In this paper we demonstrate how the translation of this untranslatable word has influenced the perception of a literary work. We focus mainly on the poem Недотыкомка серая… (1905), the title of which in Wiktor Woroszylski’s translation is Niepochwytnica szara… (1971), while in the translation by Włodzimierz Słobodnik – Niedoruszajka szara… (1971) and in the novel Мелкий бес (1905), where this fulfils an important function (in René Śliwowski’s translation of 1973 – the name of this creature is Niedotkniątko). We examine what role the character of niedotykomka has in the discussed novels and we analyze the impact translation strategies have on the image of a fictional universe as well as a lyrical situation (i.e., the change of the feminine grammatical form in the character’s name into a grammatically neuter one).

Go to article

Authors and Affiliations

Agnieszka Potyrańska
Download PDF Download RIS Download Bibtex

Abstract

The article is focused on a presentation of 16 silver calyxes owned by Mr. Piotr Maciej Przypkowski. These objects are adorned with various coins: ancient Roman (4), medieval (3), and modern (9). In addition to the coins, each vessel has Latin (12) and Polish (4) maxims as well as alchemic and astrological symbols under its rim. This is very likely the latest, attested in numismatic literature, example of historical coins being reused as decorative elements of vessels.
Go to article

Authors and Affiliations

Grzegorz Śnieżko
1
ORCID: ORCID

  1. Instytut Archeologii i Etnologii PAN, Al. Solidarności 105, 00–140 Warszawa
Download PDF Download RIS Download Bibtex

Abstract

This article presents an analysis of the Polish translation of the first poem from the series of six poems Звезда Маир (1898) by Fiodor Sologub and here in the translation by Witold Dąbrowski, Gwiazda Mair. Our task is to analyze the translation and trace to what extent the translator reflected the specificity of the lyrical situation presented in the original, and to what extent its image in the translation has changed. In addition, the focus was on translating the author’s proper names, reflecting Sologub’s creation of paradise, in order to show how specific translation activities affect the recipient’s perception of the lyrical situation shown in the poem. The rhythmic organization of the poem and the arrangement of rhymes in the original and in translation were also examined. It was shown to what extent the translators managed to reflect the hidden meanings and meaning‐creating symbols, so important for this Russian symbolist.
Go to article

Authors and Affiliations

Agnieszka Potyrańska
1

  1. Uniwersytet Marii Curie‑Skłodowskiej, Lublin
Download PDF Download RIS Download Bibtex

Abstract

In this study, Ag-impregnated silica aerogel composites were fabricated via wet impregnation. In this approach, silver salt was reduced with ethylene glycol in the presence of polyvinylpyrrolidone (PVP) at reaction temperature 80°C. PVP was used as a capping agent to protect the Ag nanoparticles (NPs) from agglomeration. Wet impregnation was used to synthesize the Ag/SiO2 composite by combining the reduction of AgNO3 with a silica aerogel slurry. Experimental results showed that the AgNO3 concentration and PVP: AgNO3 ratio had an active influence on the growth of Ag NPs on silica surfaces. The X-ray diffraction (XRD) patterns of the composite material showed no imprints of impurities or parasitic materials except for Ag and SiO2. Scanning electron microscopy (SEM) images revealed that the Ag NPs were well impregnated into the porous silica aerogel structure. It was found that SiO2 aerogel surfaces were homogeneously surrounded by the Ag NPs.
Go to article

Authors and Affiliations

Pratik S. Kapadnis
1
Kyungsun Kim
1
Hyung-Ho Park
2
Haejin Hwang
1
ORCID: ORCID

  1. Inha university, Department of Materials Science and Engineering, Incheon 22212, Republic of Korea
  2. Yonsei University, Department of Materials Science and Engineering, Seoul 03722, Republic of Korea
Download PDF Download RIS Download Bibtex

Abstract

The extraction of mineral deposits is usually charged with additional taxes or royalty fees that go beyond the general income tax. As a rule, countries prefer stable sources of fiscal revenues based on the volume of raw material extraction, and investors prefer models based on profit tax, i.e. taking operating costs and risks lower than the expected profitability of the project into account. As a rule, too high a burden for the mining sector affects investors’ decisions regarding the introduction of new investments. There are a number of examples where excessive fiscal burdens force investors to move to countries with more favorable tax systems. An analysis of various forms of taxation of mining enterprises around the world has been presented and compared with the system implemented in Poland. Usually, the countries that apply the royalty fee in the mining sector at the same time introduce a number of adaptation mechanisms. This is crucial for new investments due to the fact that they may to some extent compensate for the high costs of transition from the investment to the operational phase. In most cases, several incentive mechanisms are used at the same time, e.g. the accelerated settlement of investment expenditures and the unlimited settlement of losses. The copper and silver mining tax introduced in Poland increased the discounted effective tax rate (ETR) from 38.5% to 89% for the entire investment period, which resulted in a 11-year return on investment, as well as a drop in the internal rate of return (IRR).There are currently no mechanisms in Poland which would balance the burden of this tax for a new investor. In order to balance the extraction tax for certain minerals in terms of the IRR and ETR key indicators, the introduction of several adaptation mechanisms has been proposed. For new investments the most essential mechanism is the preferential settlement of capital expenditures incurred in the pre-production phase of an investment. The others include accelerated amortization, the ability to deduct certain expenses for the exploration phase from the tax base, along with an extended tax loss settlement period, or a mechanism for deducting a certain percentage of investment expenses directly from the tax.

Go to article

Authors and Affiliations

Stanisław Speczik
Kinga Capik
Download PDF Download RIS Download Bibtex

Abstract

The electrical contactors play a crucial role in closing the circuit in many power distribution components like overhead lines, underground cables, circuit breakers, transformers, and control systems. The failure in these components mainly occurs due to the break-down of contactors due to the continuous opening and closing action of contacts. Silver (Ag)-based oxide contact materials are widely used in practice, among which silver tin oxide (AgSnO2) is most common. An attempt is made in increasing the performance of AgSnO2, by adding Tungsten Oxide (WO3) in various weight proportions, thus finding the optimal proportion of AgSnO2WO3 to have increased mechanical and electrical performances. All the composite samples are fabricated in-house using powder metallurgy process. The assessment of physical and electrical properties namely, density, hardness, porosity, and electrical conductivity, showed that 90%Ag-8.5%SnO2-1.5%WO3 composite yielded superior results. With help of morphological tests, wear characteristics are also investigated, which showed that 90%Ag-8.5%SnO2-1.5%WO3 composite has a wear coefficient of 0.000227 and a coefficient of friction of 0.174 at an optimized load of 10 N and sliding velocity of 0.5 mm/s.
Go to article

Bibliography

[1] P.B. Joshi, N.S.S. Murti, V.L. Gadgeel, V.K. Kaushik, J. Mater. Sci. Lett. 14 (16), 1099-1101 (1995). DOI: https://doi.org/10.1007/BF00423372
[2] P.B. Joshi, P. Ramakrishnan, Materials for electrical and electronic contacts: processing, properties, and applications, Science Pub Inc. (2004).
[3] Z. Ying, W. Jingqin, K. Huiling, IEEE T. Comp. Pack. Man. 9 (5), 864-870 (2018). DOI: https://doi.org/10.1109/TCPMT.2018.2882237
[4] P.B. Joshi, V.J. Rao, B.R. Rehani, A. Pratap, Silver-Zinc oxide electrical contact materials by mechanochemical synthesis route (2007).
[5] B. Holm, Northwest coast Indian art: An analysis of form. University of Washington Press (2017).
[6] O. Nilsson, F. Hauner, D. Jeannot, Replacement of AgCdO by AgSnO/sub 2/in DC contactors, In Proceedings of the 50th IEEE Holm Conference on Electrical Contacts and the 22nd International Conference on Electrical Contacts Electrical Contacts. (pp. 70-74). IEEE (2004 September). DOI: https://doi.org/10.1109/HOLM.2004.1353097
[7] D .A. Romanov, S.V. Moskovskii, E.A. Martusevich, E.A. Gayevoy, V.E. Gromov, Structural-phase state of the system “CdO-Ag coating/copper substrate” formed by electroexplosive method. Metalurgija 57 (4), 299-302 (2018).
[8] P.G. Slade, R.K. Smith, Electrical switching life of vacuum circuit breaker interrupters. In Electrical Contacts-2006. Proceedings of the 52nd IEEE Holm Conference on Electrical Contacts (pp. 32- 37). IEEE (2006, September). DOI: https://doi.org/10.1109/HOLM.2006.284061
[9] S.H. Choi, B. Ali, S.Y. Kim, S.K. Hyun, S.J. Seo, K.T. Park, J.S. Park, Int. J. Appl. Ceram. Tec. 13 (2), 258-264 (2016). DOI: https://doi.org/10.1111/ijac.12478
[10] C. Wu, Q. Zhao, N. Li, H. Wang, D. Yi, W. Weng, J. Alloy Compd. 766, 161-177 (2018). DOI: https://doi.org/10.1016/j.jallcom.2018.06.317
[11] J.L. Wintz, S. Hardy, Design guideline of contactors: optimal use of assembled contacts. In 2013 IEEE 59th Holm Conference on Electrical Contacts (Holm 2013) (pp. 1-10). IEEE (2013, September). DOI: https://doi.org/10.1109/HOLM.2013.6651406
[12] N.M. Talijan, V. Ćosović, J. Stajić-Trošić, A. Grujić, D. Živkovic, E. Romhanji, J. Min. Metall. B. 43 (2), 171-176 (2007). DOI: https://doi.org/10.2298/JMMB0702171T
[13] B. Rehani, P.B. Joshi, P.K. Khanna, J. Mater. Eng. Perform. 19 (1), 64-69 (2010). DOI: https://doi.org/10.1007/s11665-009-9437-3
[14] P.G. Slade, (Ed.), Electrical contacts: principles and applications, CRC Press (2017).
[15] M.W. Richert, J. Richert, A. Hotloś, P. Pałka, W. Pachla, M. Perek- Nowak, In Mater. Sci. Forum. 667, 145-150 (2011). DOI: https://doi.org/10.4028/www.scientific.net/MSF.667-669.145
[16] V. Ćosović, N. Talijan, D. Živković, D. Minić, Z. Živković, J. Min. Metall. B. 48 (1), 131-141 (2012).
[17] K. Wojtasik, W. Missol, Metal Powder Report 59 (7), 34-39 (2004). DOI: https://doi.org/10.1016/S0026-0657(04)00206-1
[18] M . Lungu, S. Gavriliu, T. Canta, M. Lucaci, E. Enescu, J. Optoelectron. Adv. M. 8 (2), 576 (2006).
[19] V. Ćosović, M.M. Pavlović, A. Cosovic, P. Vulić, M. Premović, D. Živković, N.M.Talijan, Sci. Sinter. 45 (2), 173-180 (2013). DOI: https://doi.org/10.2298/SOS1302173C
[20] N.M. Talijan, Zaštitamaterijala 52 (3), 173-180 (2011).
[21] M . Mustapha, F. Mustapha, O. Mamat, P. Hussain, Powder Metall. 54 (3), 343-353 (2011). DOI: https://doi.org/10.1179/003258909X12573447241581
[22] N.M. Talijan, V.R. Ćosović, A.R. Ćosović, D.T. Živković, Metallurgical and Materials Engineering 18 (4), 259-272 (2012).
[23] M . Braunovic. IEICE T. Electron. 92 (8), 982-991 (2009). DOI: https://doi.org/10.1587/transele.E92.C.982
[24] A . Dogariu, S. Sukhov, J. Sáenz, Nat. Photonics. 7 (1), 24-27 (2013). DOI: https://doi.org/10.1038/nphoton.2012.315
[25] M . Taher, F. Mao, P. Berastegui, A.M. Andersson, U. Jansson, Tribol. Int. 119, 680-687 (2018). DOI: https://doi.org/10.1016/j.triboint.2017.11.026
[26] F. Findik, H. Uzun, Mater. Design 24 (7), 489-492 (2003). DOI: https://doi.org/10.1016/S0261-3069(03)00125-0
[27] B.A. Wasmi, A.A. Al-Amiery, A.A.H. Kadhum, A.B. Mohamad, J. Nanomater. (2014).
[28] M . Lungu, S. Gavriliu, D. Patroi, M. Lucaci, Adv. Mat. Res. 23, 103-106 (2007). DOI: https://doi.org/10.4028/www.scientific.net/AMR.23.103
[29] M . Raja, J. Chandrasekaran, M. Balaji, P. Kathirvel, Optik 145, 169-180 (2017). DOI: https://doi.org/10.1016/j.ijleo.2017.07.049
[30] E . Harea, I. Lapsker, A. Laikhtman, L. Rapoport, L. Tribol, Lett. 52 (2), 205-212 (2013).
[31] S. Praveen Kumar, R. Parameshwaran, A. Ananthi, J. JenilJaba Sam, Arch. Metall. Mater. 62 (2017). DOI: https://doi.org/10.1515/amm-2017-0287
[32] S.P. Kumar, R. Parameshwaran, S.A Kumar, S. Nathiya, K. Heenalisha, Mater. Today-Proc. (2020). DOI: https://doi.org/10.1016/j.matpr.2020.05.666
[33] H . Li, X. Wang, Y. Xi, Y. Liu, X. Guo, Mater. Design. 121, 85-91 (2017). DOI: https://doi.org/10.1016/j.matdes.2017.02.059
[34] Mohd Shahadan Mohd Suan, Nurulhawa Ali Hasim, Mohd Edeerozey Abd Manaf, Mohd Rafie Johan, Chinese J. Phys. 55 (5), 1857-1864 (2017). DOI: https://doi.org/10.1016/j.cjph.2017.08.012
Go to article

Authors and Affiliations

S. Praveen Kumar
1
ORCID: ORCID
S.M. Senthil
1
ORCID: ORCID
R. Parameshwaran
1
ORCID: ORCID
R. Rathanasamy
1
ORCID: ORCID

  1. Kongu Engineering College, Erode, Tamilnadu, India
Download PDF Download RIS Download Bibtex

Abstract

Through the powder metallurgy technique, alloys of the eutectic composition of the Zn-Al system were manufactured (22.3 wt.%Al), reinforced with Ag additions (0.5, 1, 2.5, 5 wt.%), with subsequent annealing heat treatment at three different temperatures; 100, 150 and 200°C for 1 hr. X-ray diffraction, optical microscopy and mechanical tests were performed on the resulting samples. The addition of Ag favors the formation of alpha and beta compounds with Al and Zn respectively, which improves the compressive strength of the alloy. However, with the presence of Ag the hardness is decreased. On the other hand, the application of an annealing heat treatment, shows no significant effect on the evaluated properties of the alloy. The microstructure of the alloys resulted in the presence of very small grains smaller than 1 mm and with rounded morphology.
Go to article

Authors and Affiliations

Miguel Angel Rubio-Padrón
1
ORCID: ORCID
Olga Alondra Echartea-Reyes
1
Carlos A. Calles-Arriaga
1
ORCID: ORCID
Enrique Rocha-Rangel
1
ORCID: ORCID

  1. Universidad Politécnica de Victoria, Ciudad Victoria, México
Download PDF Download RIS Download Bibtex

Abstract

Twenty silver minerals of the sulphide, arsenide, selenide, telluride, sulphosalt and chloride groups were found in 13 locations in the Variscan Karkonosze granitoid pluton. Previously only one of these minerals was known from this area. The findings include species characterized in publications as rare or exceptionally rare, e.g., muthmannite and tsnigriite. They occur in pegmatites and quartz veins; their parageneses are described. The studies include determination of chemical compositions, formulae calculations and recording of XRD patterns. Inclusion studies in paragenetic quartz indicate that they crystallized from epithermal fluids with a common but low component of CO 2. The results suggest that the minerals formed from trace elements (Ag included) in the Karkonosze granitoid due to very local degrees of recrystallization of the host granitoid.
Go to article

Authors and Affiliations

Andrzej Kozłowski
1
Witold Matyszczak
1

  1. University of Warsaw, Faculty of Geology, Żwirki i Wigury 93, 02-089 Warszawa, Poland
Download PDF Download RIS Download Bibtex

Abstract

ABSTRACT:

The main goal of this publication is to familiarize western numismatists with the current trends and findings in the research on medieval payment ingots (grivnas) in Eastern Europe. The author presents up-to-date chronological classification of silver payment ingots, shortly describes their basic types and gives the basic list of classic and modern works in this field.

Go to article

Authors and Affiliations

Ilya Shtalenkow
Download PDF Download RIS Download Bibtex

Abstract

Modern archaeological research uses physico-chemical methods to answer questions beyond the scope of the conventional historian’s workshop. This applies to research on the borderline of fields, including material research into the elemental and isotopic composition of artefacts. The results of such analyses make it possible to address issues relating to the distribution of raw materials and the technology of artefact production. The paper discusses the SEM-EDS and LA-ICP-QMS micro-analysis methodology, addressing the limitations that result from the specification of techniques and the state of preservation of archaeological artefacts due to corrosion processes and conservation treatment. We present the preliminary results of technological research and provenance study of early medieval objects made of silver alloys, considered by typological group, i.e. coins, cake, and jewellery. Two hundred objects were analysed, revealing clear evidence for the use of remelted dirhams as the main source of raw material. The results of the research allowed for a material description of the phenomenon of the existence of cores in cross denarii, distinguishing two types of cores: based on copper and brass. In the case of jewellery, the research provided evidence for technological distinction, indicating the use of copper-based solders, as well as tin- and lead-based dolders, which have analogies in goldsmithing material from the Czech Republic. Recipes based on the marked composition are described in ancient sources. Silver cakes, on the other hand, can be divided into three extraction groups related to the degree of purification of the raw material. The preliminary results indicate that these objects were made of Asian dirhams and native lead, perhaps as an additive in the cupellation process.
Go to article

Authors and Affiliations

Ewelina Miśta-Jakubowska
1
ORCID: ORCID

  1. National Centre for Nuclear Research, Andrzeja Sołtana 7, PL 05–400 Otwock, Poland
Download PDF Download RIS Download Bibtex

Abstract

The aim of the research was to analyze the degree of infection of winter wheat by fungal diseases and to evaluate the morphological and physiological parameters of plants depending on varied foliar fertilization (with and without the ionic form of silver) and applied plant protection agents (active ingredients: propiconazole, fenpropidin, azoxystrobin) in the 2016/2017, 2017/2018 and 2018/2019 growing seasons. The results showed that micronutrient fertilizers with silver and pesticides reduced the severity of fungal diseases better than the control. In most cases, foliar fertilizers enriched with the ionic form of silver at a dose of 1 and 2 l · ha −1 were the most effective. Moreover, foliar fertilization and pesticides had a positive effect on the morphology of wheat. Combined treatment (micronutrient fertilizer with silver and pesticide at a dose of 1 l · ha −1) increased stalk length and weight, ear weight and thousand grain weight to the greatest extent in comparison to the other treatments, while the pesticides stimulated ear length the most. In turn, microelement fertilizers with silver at a dose of 1 and 2 l · ha −1 were better in terms of flag leaf length. Wheat treated with foliar fertilizer and pesticide significantly improved the chlorophyll content based on the leaf greenness index (SPAD). It was found that the foliar application of microelements with silver is promising for use in agriculture because they controlled fungal diseases and ensured the good condition of plants more effectively than pesticides harmful to the environment.
Go to article

Authors and Affiliations

Ewelina Matras
1
ORCID: ORCID
Anna Gorczyca
1
ORCID: ORCID
Marek Kołodziejczyk
2
ORCID: ORCID
Bogdan Kulig
2
ORCID: ORCID
Sebastian Wojciech Przemieniecki
3
ORCID: ORCID

  1. Department of Microbiology and Biomonitoring, University of Agriculture in Krakow, Krakow, Poland
  2. Department of Agroecology and Plant Production, University of Agriculture in Krakow, Krakow, Poland
  3. Department of Entomology, Phytopathology and Molecular Diagnostics, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland
Download PDF Download RIS Download Bibtex

Abstract

In 2009, in the village of Wysoczany, Sanok district, Podkarpackie voivodeship, a silver coin was accidentally found. This coin is a tetradrachm. It has irregular oval shape and is plano-convex. It is not well preserved, i.e. it has poorly legible depictions on both sides, which significantly impedes its typological classification, and thus its precise dating. The dimensions of the coin are: 27.5 × 28.5 mm and its weight is: 11.83 g (after conservation works). In the case of the described here coin there are no clear analogies and, therefore, there is no certainty to what type it should be attributed. This paper attempts to analyse a few of the existing possibilities. One of the taken into consideration is the south-eastern direction, i.e. Geto-Dacian mintage or Celtic Geto-Dacian one. Some similarities can be found in the following types: Agriş A — Şilindia, Ramna, and also in the category referred to as “the other types” according to the typology by C. Preda. The other possible direction is the central Celtic mintage associated with Boii. However, none of the examples presented in this paper is a close analogy to the coin from Wysoczany. Therefore, its typological attribution as well as its dating remain to be an open question.

Go to article

Authors and Affiliations

Iwona Florkiewicz
Piotr N. Kotowicz

This page uses 'cookies'. Learn more