Metal Coins Research Articles

Surface, Elemental and Electrochemical Characterizations of Ancient Coins By Non – Destructive Techniques

Abstract The cultural heritage field represents a witness to artifacts values in a continuous evolution, it strongly influences our sense of identity and our behavior as people. To protect these archaeological treasures, different conservation and restoration methods are required. Considering the field of priceless artifacts, our research direction led us to preliminary studies of metallic coins from 20th century through non–destructive techniques. Copper–based coins were subjected to the surface characterization through optical microscopy (OM) in transmitted light, elemental composition analysis using Wavelength Dispersive X-ray Fluorescence (WDXRF) and electrochemical corrosion using Tafel extrapolarization technique. The microscopic investigations showed that the patina layer is due to presence of copper content in coins composition confirmed by X-ray fluorescence spectroscopy technique. Also, the electrochemical tests disclosed different corrosion rate according to each chemical composition of coins. This study provide a broad overview of ancient coins to preserve their value in the future.

Identification of Microbial Contamination: Isolation from Metallic Coins

Identification of Microbial Contamination: Isolation from Metallic Coins

A Model for Minimizing the Cost of Distributing Metallic Coins in Mexico

A Model for Minimizing the Cost of Distributing Metallic Coins in Mexico

The Importance of Corrosion Protection of Metal-Containing Historical Artifacts and Common Methods Used for Preservation

Metal objects were used for various purposes like in the production, decoration, and painting of metallic coins, kitchenwares, and as structural components from ancient ages to the present. Metal extraction and processing ability became one of the important factors to determine the development level of society. For this reason, repairing and protecting the ancient artifacts buried underground or in an aqueous environment that recovered from the archaeological excavations and historical sites is extremely important to protect the history and cultural heritage of society. Historical artifacts are very fragile against environmental factors after their removal from the dig sites and thus rapid intervention procedures are required. Furthermore, historical artifacts exhibited without an application of a protective coating can easily corrode at an increased rate against atmospheric conditions over time. Therefore, developing new approaches for the preservation of metallic objects of cultural heritage has significant importance. It is necessary to know the type of metal to be processed as the coating to be developed for protection will be determined according to the type of metal. Primarily, metal surfaces must be cleansed from the corroded layer followed by developing and applying a structure able to isolate the metal from the environment in order to prevent corrosion. Various materials such as waxes, oils and greases, polymers, glasses and glassy enamels, metallic, and organic coatings have been used to develop corrosion-resistant coatings. Soluble corrosion inhibitors have also been used, which can promote the spontaneous formation of a protective barrier film on surfaces. The structures to be used in the protection of the ancient artifacts must have specific features: • must not cause a change in color and has to preserve authenticity in visual appearance, • easy to apply, • low cost, • reversibility in some cases, i.e. easy to remove from the surface, • environmentally friendly, non-toxic. In this review, the methods commonly used for the protection of archaeological artifacts are examined and their advantages and disadvantages are stated.

On the issues of ensuring the information security of the financial sector of the Russian Federation

The article is devoted to one of the most pressing problems of the modern digital economy - its information security. To a greater extent, this applies to the financial sector, which carries out electronic transactions and is actively looking for more efficient analogues of metal coins, paper banknotes, etc. The main reason for these problems is an acute shortage of specialists who possess modern information technologies and understand the essence of the ongoing changes associated with the digital transformation of economic processes. The ways of overcoming the personnel shortage and repelling cyber attacks in financial structures are considered.

A Fe3N/carbon composite electrocatalyst for effective polysulfides regulation in room-temperature Na-S batteries

The practical application of room-temperature Na-S batteries is hindered by the low sulfur utilization, inadequate rate capability and poor cycling performance. To circumvent these issues, here, we propose an electrocatalyst composite material comprising of N-doped nanocarbon and Fe3N. The multilayered porous network of the carbon accommodates large amounts of sulfur, decreases the detrimental effect of volume expansion, and stabilizes the electrodes structure during cycling. Experimental and theoretical results testify the Fe3N affinity to sodium polysulfides via Na-N and Fe-S bonds, leading to strong adsorption and fast dissociation of sodium polysulfides. With a sulfur content of 85 wt.%, the positive electrode tested at room-temperature in non-aqueous Na metal coin cell configuration delivers a reversible capacity of about 1165 mA h g−1 at 167.5 mA g−1, satisfactory rate capability and stable capacity of about 696 mA h g−1 for 2800 cycles at 8375 mA g−1.

Rational design of mechanically robust Ni-rich cathode materials via concentration gradient strategy

Mechanical integrity issues such as particle cracking are considered one of the leading causes of structural deterioration and limited long-term cycle stability for Ni-rich cathode materials of Li-ion batteries. Indeed, the detrimental effects generated from the crack formation are not yet entirely addressed. Here, applying physicochemical and electrochemical ex situ and in situ characterizations, the effect of Co and Mn on the mechanical properties of the Ni-rich material are thoroughly investigated. As a result, we successfully mitigate the particle cracking issue in Ni-rich cathodes via rational concentration gradient design without sacrificing the electrode capacity. Our result reveals that the Co-enriched surface design in Ni-rich particles benefits from its low stiffness, which can effectively suppress the formation of particle cracking. Meanwhile, the Mn-enriched core limits internal expansion and improve structural integrity. The concentration gradient design also promotes morphological stability and cycling performances in Li metal coin cell configuration.

3D Modelling and FEM Analysis on Metal Coin Edge Punching Error

Minting metal coin, mean to impress a given relief model on both coin faces and also on the edge. Due to the high striking pressure, the round blank material is forced to fill the inner space between dies. In the past, for less coin value, the coin edge remained cylindrical, without any inscription. Following the increased coin value, it was introduced a security feature against forgery; on the coin edge model could be toothed or inscribed with relief or incuse text logo. Besides the coin edge basic design, a various amount of coin edge error types are released. In the paper there are studied some errors on the metal coin edge impressed with incuse text by punching. First, there are presented some particular examples and general aspects about the coin edge punching are also introduced. Then, the simplified 3D model of the parts is presented. Also, the finite element analysis on this model is realized and is achieved for different initial conditions. In the final part, the analysis results and conclusions are presented.

Independent friction-restitution modeling of two-disk collisions

The oblique collisions between two axisymmetric disks moving on a flat horizontal surface are described in terms of impact modeling based on the assumption that normal and tangential restitution mechanisms operate independently of friction. Describing these mechanisms in terms of the usual Coulomb formulation, the model allows for an interpretation of some “anomalous” experimental data reported in the literature. These experimental data, corresponding to the variation of the coefficients of friction and tangential restitution with the impact angle, remained unexplained in classic formulations, are understood within the framework of the independent friction-restitution closure. Experimental data for metallic coins are in agreement with that formulation, including rolling friction effects.

Considerations on Fractional Reserve Banking and Free-Banking

In this article, our goal is to examine a controversy very dear to Austrian economists: that of the legitimacy of the fractional reserve banking system, defined as a system in which the bankers keep in their vaults a quantity of money (narrowly defined) lower than the quantity of cash deposits granted to their clients.
 In the Austrian vision, the monetary supply, broadly defined (Mises, 1971), consists of money properly said, plus monetary substitutes (bank notes, cash deposits), plus credit-money, this one corresponding to any future right to a monetary sum (time deposits, promissory notes, pre-fixed derivatives). In a narrow sense, money supply consists in money properly said (fiat-money or commodity money).
 We must, however, clarify some aspects of the money supply. Monetary substitutes have their origin in the monetary certificates. Monetary certificates, in their turn, are tools utilized to confer information about the medium of exchange. For instance, precious metal coins mintage confers information about the metal’s purity and about the weight of the coin; bank notes and current account balances confer information about the amount, overseer and proprietor of the deposited money. So, money certificates can change the agents’ valuations concerning the particular good in question, even being able of independent valuation. Monetary certificates can be physically connected to the medium of exchange or separated from it. In the case of physically connected monetary certificates, we have what we normally call monetary substitutes. Monetary substitutes can, due to their nature, work as property titles to the very medium of exchange. Contemporaneously, monetary substitutes usually can be identified with cash deposits (current account balances) and paper checks, provided that the use of bank notes is increasingly rare.
 Having made those clarifications concerning monetary substitutes, we will, following Mises (1971, p. 135), call fiduciary media the quantity of monetary substitutes that exceeds the quantity of money properly said.
 However, before proceeding with our Investigation about the consequences of the legalization of the production of fake monetary substitutes (fiduciary media), we must explain what would be a fake monetary substitute and the nature of this counterfeiting. We must, therefore, start our argumentation establishing some differences about the nature of loan and deposit contracts [x].

Revisiting the Properties of Money

The properties of money commonly referenced in the economics literature were originally identified by Jevons (1876) and Menger (1892) in the late 1800s and were intended to describe physical currencies, such as commodity money, metallic coins, and paper bills. In the digital era, many non-physical currencies have either entered circulation or are under development, including demand deposits, cryptocurrencies, stablecoins, central bank digital currencies (CBDCs), in-game currencies, and quantum money. These forms of money have novel properties that have not been studied extensively within the economics literature, but may be important determinants of the monetary equilibrium that emerges in the forthcoming era of heightened currency competition. This paper makes the first exhaustive attempt to identify and define the properties of all physical and digital forms of money. It reviews both the economics and computer science literatures and categorizes properties within an expanded version of the original functions-and-properties framework of money that includes societal and regulatory objectives.

Monetary Famine, Paper Money, and International Constraints on Economic Growth: The Case of Colonial Quebec

New France, like most European colonies in the New World, suffered from a persistent shortage of metal coins. As Quebec could only legally import from France, their standards of living were constrained by their ability to export a few primary products (mostly fur, cod, timber and wheat). Mercantilist restrictions and underdeveloped financial markets limited the ability to use the capital account to import coins and tightened the balance of payments constraint. The introduction of playing card money in New France in 1685, the first use of paper money in the West, provided a means of relaxing this constraint. It produced a substitute domestic money which allowed scarce metal coins to be used to purchase imports. The balance-of-payments constrained growth models that grew out of Thirlwall’s Law is applied to this experience, with discussions of the export constraints of Quebec’s reliance on a few primary exports (with furs being the most dominant one) with inelastic demand and facing the vagaries of changing tastes in Europe.

Stabilizing High-Rate Lithium Electroplating Via Inter-Electrode Thermal Gradient at Low Temperature

Temperature is known to significantly influence battery electrochemistry and performance due to its strong dependence on kinetics and diffusion. To date, the role of temperature on battery behavior has mostly been considered in an isothermal case. We have shown previously that applying a negative thermal gradient (cathode warmer than anode) in conventional Li+-ion batteries with graphite anodes exacerbates Li plating at the anode, loss of lithium inventory, and rapid loss of cell capacity (1). We have also shown previously that applying inter-electrode thermal gradients in lithium symmetric cells at moderate current densities (1.5 mA cm-2) can significantly improve performance and long-term cycling stability. The direction of an inter-electrode thermal gradient governs lithium plating morphology and dictates whether unstable, one-dimensional Li electroplating or stable, more homogeneous electroplating occurs (2). With a warmer positive electrode (40°C) and a colder negative electrode (0°C) (negative thermal gradient) we previously observed unstable cell behavior, extensive side reactions between Li and the electrolyte, and internal shorting. Reversing these temperatures in the symmetric Li cell so that the negative electrode is warmer than the positive electrode (positive thermal gradient) decreases overpotentials, minimizes deleterious side reactions between Li and the electrolyte, and encourages long cycle life.This presentation studies the effects of a positive thermal gradient during high-rate electroplating and stripping and shows the promise that this novel thermal control holds for enabling fast-charging in lithium metal batteries. First, we will use symmetric Li metal coin cells to investigate the roles of thermal gradient magnitude and electrode temperatures on high-rate (10 mA cm-2) lithium plating stability. We couple trends in electrochemical impedance spectroscopy (EIS) throughout cycling with post mortem imaging and microscopy to quantify extents of Li deactivation as a function of the applied thermal condition. After identifying optimal thermal conditions for highly reversible Li electroplating and stripping with symmetric Li metal cells, we apply this thermal gradient to an anode-free full cell with a LiFePO4 cathode. Operando video microscopy of Li electrodeposition onto a copper substrate confirms that a positive thermal gradient favorably alters the morphology of electroplated Li compared to isothermal control. Internal thermal sensing and EIS, as well as post mortem materials characterization, including X-ray diffraction (XRD) and scanning electron microscopy (SEM), will be used to discuss and characterize cell behavior in the presence of an applied thermal gradient.References R. Carter and C. T. Love, ACS Appl Mater Interfaces, 10, 26328 (2018).R. W. Atkinson III, R. Carter and C. T. Love, Energy Storage Materials, 22, 18 (2019). DISTRIBUTION A: Approved for public release, distribution is unlimited.

Traditional conservation on Chinese Metal Coins (Kepeng) from sangkulu-kulu underwater archaeological sites, Selayar Regency

This study aims to carry out conservation using a traditional approach to the artifacts of Chinese metal coins (kepeng) that are raised from the Sangkulu-kulu Selayar underwater site. The natural ingredients used are a solution of wuluh starfruit (Averrhoa Bilimbi), maja fruit solution (Aegle Marmelos (L) Correa), lime juice (Citrus Aurantifolia), tamarind juice (Tamarindus Indica) and coconut water (Cocoa nutifera). The methods used include identification of weathering. The second stage is of XRF analysis. The third stage is immersion with a conservative ingredients solution. The results showed that of the five solutions used in the cleaning of 3 types of weathering in the coin sample, the lime solution was faster in removing three types of weathering (chemistry, physical and biotic), especially for the types of chemical and biotic weathering. Acidic solutions are used to remove active patina; a tamarind solution is the most effective solution in eliminating physical weathering by a process that lasts slowly or little by little.

CREDIT AND THE PROBLEM OF TRUST IN THE THOUGHT OF JOHN LOCKE, c. 1668–1704

AbstractThis article presents a reinterpretation of John Locke's contribution to debates about the interest rate in the seventeenth century. It suggests that his argument that England should maintain the ‘natural’ rate, rather than impose a lower rate, was motivated by his theological, moral, and social conceptions of credit and its dependence on trust. In order to solve the endemic shortage of metal coin limiting the growth of monetary exchange in England, Locke stressed that the higher, ‘natural’ rate of interest would facilitate interpersonal borrowing and lending among neighbours, allowing currency to flow more freely around the country. By contrast, while he acknowledged that institutional creditors such as goldsmith-bankers could quicken the circulation of money by issuing debt instruments like bills of exchange, he saw institutional credit as a threat to the moral community. Not only did he question how people could rationally trust financiers without any epistemic apprehension of their personal probity, but he moreover doubted whether individuals accumulating so much money were likely to act trustworthily. Finally, using an otherwise unstudied dialogue about the Bank of England, this article argues Locke extended his criticisms about the threats posted by private banks to the country's nascent system of public credit.

An Evaluation of Laser Cleaning as a Conservation Technique for an Archaeological Metal Coins

An Evaluation of Laser Cleaning as a Conservation Technique for an Archaeological Metal Coins

Stabilizing Anode-Free Lithium Batteries Via External Thermal Gradients

Temperature is known to have a profound impact on battery electrochemistry and performance due to the strong temperature-dependence of kinetics and diffusion. However, the role of temperature on battery behavior has mostly been considered in the case of an isothermal cell. Though active thermal management systems for batteries strive to maintain isothermal control, localized thermal gradients can still develop within individual cells, which can significantly influence local electrochemistry. For this reason, it is important to understand the consequences and also the potential benefits of non-uniform temperature distribution across batteries.Thermal gradients have been applied to lithium symmetric cells to significantly improve performance and stability. The direction of an interelectrode thermal gradient governs lithium plating morphology and dictates whether unstable, one-dimensional Li electroplating or stable, homogeneous electroplating occurs (1). With a warm positive electrode (40°C) and a cold negative electrode (0°C) (negative thermal gradient) we observe unstable cell behavior, extensive side reactions between Li and the electrolyte, and internal shorting. Reversing these temperatures so that the negative electrode is warmer than the positive electrode (a “positive” thermal gradient) decreases overpotentials, minimizes deleterious side reactions between Li and the electrolyte, and encourages long cycle life. Additionally, a positive thermal gradient stabilizes high-rate plating and stripping (1), showing promise for enabling fast-charging in lithium metal batteries.This presentation will discuss the impact of thermal gradients on stabilizing lithium plating and stripping and its application for improving long-term cycle life in anode-free lithium metal batteries. First, we will use symmetric Li metal coin cells to investigate the roles of thermal gradient magnitude and electrode temperatures on lithium plating stability. After identifying optimal thermal conditions for highly reversible Li plating and stripping, we will apply this thermal gradient to an anode-free full cell with LiFePO4 cathode to confirm its benefit on long-term cycling in a practical cell. Operando techniques, such as optical microscopy and internal thermal sensing, as well as post mortem materials characterization, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy, will be used to describe and characterize cell behavior in the presence of an applied thermal gradient.

Potentials of traditional cash metal coins versus digital contactless payment in the time of coronavirus pandemic

This paper addresses the challenges associated to the strength of potential for payment with traditional metal cash and paper money versus a non-cash method of payment in the era of the COVID 19 pandemic in the world and our country. The pandemic served to accelerate the contactless method of payment, because payment without contact is now not only a convenience, but a necessity. Before the pandemic in Europe, cash accounted for close to half of the payments, and in just a few weeks of the COVID 19 pandemic, it fell by 10 percent. Concepts that have so far preferred cash were definitely compromised during the pandemic crisis, and the pandemic is actually the strongest marketing of digital contactless payment methods so far, through the dominant contactless style of money exchange in the world and Europe, as shown in the paper we have today. Some research studies described in the paper in form of the health adventages of mobile wallet payments, as opposed to the proven health-threatening cash and coin-based cash payment model, indicate that the end of the cash era is approaching, being primarily accelerated by the health risk of COVID 19 infection. Particularly interesting is the live study conducted in the area of the northern Kosovo and Metohija, presented in a form of a set of financial services offered by the Postal Savings Bank of the Kosovska Mitrovica branch office, and relation between the contactless and cash payment model, before and after the COVID 19 pandemic. Naturally, all of this is accompanied by significantly limited knowledge related to SARS Cov 2, better known as the current COVID 19 pandemic.

Coins and cultural contact: adoption and use of metal coins by non-Greeks in ancient Calabria (6th- 5th centuries BC.)

We are all familiar with the main questions involved in the adoption and use of coined metal by the Greeks back in the 6th-5th centuries BC; questions such as the steps in the expansion in the Mediterranean area of the habit of coining; abstract value and concrete value; intrinsic value and “fiduciarity” of coined money and so forth. In this short paper, our intention is to focus attention on coin and metal finds in general (hoards, excavations, sporadic findings) in Southern Italy during the 8th- 5th centuries BC our case study intends to call attention to the ways of contact between the apoikiai and non-Greeks communities showing how the expansion of coinage promoted cultural change in this area and period specially as far as the notion of value goes.

Основные черты денежного обращения на Дальнем Востоке России в период Гражданской войны (1918–1922 гг.)

The paper considers the main features and peculiarities of money circulation in the Russian Far East during the Civil War (1918–1922) and foreign military intervention in the region. The information on main issuers and money emissions of this period of history is disclosed, taking into account the regional aspect. The main factors influencing local money circulation are indicated, such as: predominant paper money turnover, a large number of monetary surrogates, low turnover of metal coins, counterfeiting, the presence of currency profiteers and foreign monetary expansion. The attention is drawn to the attempts of Japan, using the situation in the region and pursuing its political and economic goals, to introduce its own special banknotes into the economy of the Far East in order to displace the local currency and take control of the local market.