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The process of extraction/re-extraction of copper from heap leaching solutions using the Acorga M5774 Solvay extractant (Sytec, Belgium/USA) representing a modified aldoxime (5-nonylsalicylaldoxime) was studied. This extractant is characterized by a high effectiveness and a large selectivity of copper to iron, thus enabling a more rapid phase separation. During experiments, a pregnant leach solution obtained after the percolation leaching of the Sayak deposite ore (Republic of Kazakhstan) was used, g/dm3: H2SO4 – 11.67, Сu – 2.44, Fe – 2.613, Al – 0.345, Si – 0.127, Zn – 0.05, рН = 1.85. The main parameters and effectiveness of the extractant were studied by plotting extraction and re-extraction isotherms, as well as by simulating the closed cycle processing sequence and determining the level of copper extraction at the liquid extraction stage. The extraction/re-extraction of copper from pregnant leach solutions was studied. An aliphatic product of Elixore 205 (Total, France) was used as an extractant diluent, with the amount in the organic phase equal to 90%. Based on the conducted studies, extraction and re-extraction isotherms were plotted. In the liquid extraction process, simulated using the obtained isotherms, the extraction of copper comprised 96.18% (at an organic/aqueous phase ratio of 1.1) with a reagent saturation of 79%. The dependence of iron transfer from the organic phase on the saturation of organic phase with copper was obtained. Thus, the performed studies confirmed the effectiveness of the Acorga M5774 extractant for the purposes of extracting copper from pregnant leach solutions obtained during heap leaching of the Sayak deposit ore.

We expect global potential output growth to increase from 2.5% in 2022 to 2.8% by 2026. Compared with the April 2022 staff assessment, global potential output growth is marginally slower. The current range for the US neutral rate is 2% to 3%, unchanged from the last annual assessment., Nous nous attendons à ce que la croissance de la production potentielle mondiale passe de 2,5 % en 2022 à 2,8 % d’ici 2026. Cette croissance est un peu plus modérée que nous l’avions anticipé dans l’évaluation d’avril 2022. Quant à la fourchette des estimations du taux neutre aux États-Unis, elle reste inchangée depuis la dernière évaluation annuelle, soit entre 2 et 3 %.

The use of hydrochloric acid for processing aluminum-containing raw materials has a number of advantages over other acids, which include: easy decomposition of aluminum compounds with the transfer of aluminum into solution; low solubility of silica in HCl, the possibility of complete separation of the solid residue without significant losses of acid, etc. The paper considers the possibility of using the method for processing ash and slag dumps accumulated in large volumes in the country. Based on the thermodynamic analysis of reactions of interaction between ash components and hydrochloric acid, the behavior of aluminum, iron and nonferrous metal compounds during leaching is studied. It was shown that the preliminary roasting of ash with calcium chloride provides a high extraction of aluminum in the solution from the cinder. Based on experimental studies, the influence of time, temperature and acid consumption on the degree of aluminum extraction into the solution has been established. At optimal conditions of leaching conducted at S:L = 1:3, T = 60 ºC, τ = 60 min extraction of aluminum in a solution as chloride amounted to 99.92 %. At the same time the extraction of silica in solid sediment due to the maximum transfer of impurities in the solution was 99.8 %. The mechanism of the leaching process is proposed. The values of activation energy and the order of the reaction, indicating the complex 3-step character of the reactions, have been calculated. It is established that the limiting stage during leaching is the dissolution of anorthite.

In this work the issue of processing of dross with preliminary separation of the metal part from the oxide one is reviewed. Based on a comparative analysis of the results of known works it is shown that this approach can be quite effective if a technology is developed for the separate processing of the oxide part to obtain a commercial product. The authors of this work proposed carrying out chlorinating roasting under oxidizing conditions with various chlorine-containing reagents as one of the effective ways of processing the oxide part of the dross. Based on the thermodynamic analysis of the reactions of interaction between the components of the oxide part of the dross and calcium and ammonium chlorides, the principal possibility of obtaining pure zinc oxide, suitable for use as mineral additives in animal feed has been shown. As a result of thermodynamic calculations of the reactions of interaction of impurity metals with calcium chloride and ammonium chloride, the values of Gibbs free energy and reaction rate constants were determined in the temperature range 973 and 1373 K. It has been established that under the conditions of roasting the oxide part of the dross with both calcium chloride and ammonium chloride, a high degree of sublimation of impurity metals from the dross in the form of their chlorides into dust is achieved. It has been shown that roasting the oxide part of the dross using ammonium chloride is more efficient than with calcium chloride.

New experimental results have been obtained on the behavior of arsenic and other associated metals (Re and others) under conditions of oxidative and reductive sintering. It has been established that the extraction of arsenic strongly depends on the process temperature during oxidative sintering. The extraction of arsenic into dust media at 873 K is 50% and rhenium is 88–90%. The effect of excess air on the extraction of arsenic and rhenium into dust was studied: the higher the excess air coefficient, the more complete the extraction of arsenic and rhenium into the dust. The obtained data indicate that achieving a high level of arsenic extraction from the initial product is not possible during oxidative sintering. The best arsenic removal results were reached under the conditions of reductive sintering of initial material by natural gas. The extraction of arsenic into dust at 823 K was 88%, and at 1373 K arsenic is almost completely converted into dust. Obtained new experimental results have a fundamental importance for the selection and organization of a comprehensive technology for the processing complex in composition refractory gold-copper-arsenic-bearing products.

This article combines individual data from household surveys in the Latin American countries to obtain a regional income and analyse its distribution and recent changes. It concentrates upon whether distributive changes in the countries over the past decade have improved income distribution between individuals or widened gaps. The region’s indicators of global inequality declined considerably during 1997-2014. This decline in global inequality is explained essentially by the reduction of inequality within Latin American countries, especially in Brazil. The incomes of the inhabitants of Latin America are now more equal in relative terms than a decade ago, although differences in the countries’ average incomes have increased.

The practicability of improving the existing technology of converting copper mattes by comelting with the difficult-toprocess high-sulfur copper-zinc concentrate. The basis for research in the behavior of non-ferrous metals, arsenic and antimony is thermodynamic analysis of the reactions of matte components, converter slag and copper-zinc concentrate interaction in the temperature range 1073–1573 K. The behaviour mechanism of copper, zinc, lead, arsenic, and antimony compounds during co-processing of copper-zinc concentrate with matte is established. High values of the Gibbs free energy of reactions of interaction between oxides of lead and zinc with elemental sulfur, sulfides of non-ferrous metals and iron show the feasibility of the highest possible extraction of lead and zinc into dust in the form of their volatile compounds: sulfides, as well as oxides of lead and zinc in the metallic state in the form of gas. There is shown the possibility of the highest possible extraction of arsenic and antimony into dust by means of converting their nonvolatile pentavalent oxides (As2O5, Sb2O5) into volatile trivalent oxides (As2O3, Sb2O3) and non-toxic sulfides (As2S3, Sb2S3) by the converter slag sulfidizing with the components of copper–zinc concentrate: elemental sulfur and iron sulfide. Direct processing of copper-zinc concentrate in converter allows selective extracting copper into matte as well as lead and zinc into a rich semiproduct suitable for their extraction by existing technologies. It is shown that a significant quality improvement of the resulting converter slag and blister copper is achieved by the high sublimation of arsenic and antimony into dust under conditions of converting copper-lead mattes together with a high-sulfur concentrate.

The solubility of oxygen in mattes of various compositions was determined based on the study of the equilibrium of the copper–lead matte–gas phase system. The experiments were conducted with different compositions of synthetic matte with copper content ranged from 25% to 45%. The behaviour of iron and lead compounds and their effect on the oxygen content in copper–lead matte were studied. The pattern of oxygen solubility was established and factors affecting the formation of quantitative ratios of the forms of oxygen in copper–lead mattes were identified. We put forward a statement that oxygen in copper–lead matte dissolves in the form of wustite (FeO) and magnetite (Fe3O4). The content of Fe3O4 is directly dependent on the content of FeS in copper–lead matte and strongly correlated with it. An increase of the content of non-ferrous metals in copper–lead matte leads to a reduction of the content of FeS and consequently of that of Fe3O4. The research revealed that unlike the copper-rich mattes, the main characteristics that determine the properties of copper–lead mattes are the content of copper, lead and oxygen, as well as the quantitative ratio of the forms of iron. Regression equations were constructed to predict the content of FeO and Fe3O4 in copper–lead mattes depending on their composition.

We describe a process of chlorination of fly ash with either chlorine gas or calcium chloride, which successfully decomposes mullite and permits the extraction of a number of industrially useful, acid-soluble compounds. As a guide for determining optimal input molar ratios and temperatures, the Gibbs energies for three groups of reactions of major fly ash components between 973 K and 1473 K were calculated: (1) chlorination with chlorine gas; (2) chlorination with chlorine gas in the presence of coal; (3) chlorination with calcium chloride. Laboratory-scale measurements with fly ash from six coal combustion power plants in Kazakhstan show that chlorination with either calcium chloride or chlorine gas allows efficient extraction of alumina (α-Al2O3) and silica with both high yield and purity.

The purpose of this work is to improve the technological indicators of the existing mine contractile smelting technology by joint smelting of intermediate products, recycled materials of lead production with high-sulfur copper-zinc concentrate. It is established that during the smelting of copper-zinc concentrate which is difficult to process, high selective extraction of copper into matte and zinc into slag is achieved in one stage. The method consisted in the joint smelting of lead intermediates and high-sulfur copper-zinc concentrate in an electric furnace at a temperature of 1250 ° C under conditions of sequential blowing of the melt with air, then with natural gas. It is established that when the melt is purged with air and natural gas for 20 minutes, an equilibrium distribution of metals between the melting products is achieved. It is shown that simultaneous use of copper-zinc concentrate as a sulfidizer reduces the content of copper and lead in slag, increases the extraction of arsenic and antimony into the dust. Consumption of coke and quartz flux is reduced in comparison with the existing technology from 6.7 to 2.5% and from 12.5 to 2.8% of the initial feed weight, respectively, which significantly reduces material and energy costs of the process. As a result of extensive laboratory testing, the optimum composition of the new charge has been selected. Metal distribution between smelting products of the new charge with addition of 30% of high-sulfur copper-zinc concentrate was established. High recovery of copper to the matte up to 94.8%, against 83.7% according to the existing technology; lead to the rough lead - up to 93.6%, against 70.8%; zinc to the slag - up to 94.7%, against 83.7%; arsenic to the dust - up to 91%, against 69.5% and antimony to the dust - up to 92.3%, against 60.0% according to the existing technology.

In November 2020, the Bank of Canada launched a pilot project with the Office of the Superintendent of Financial Institutions aimed at better understanding risks to the economy and the financial system related to climate change. Part of this work included developing a set of Canada-relevant climate transition scenarios that explore pathways consistent with achieving certain climate targets. The scenarios vary in terms of two key drivers of climate transition risk: (i) the ambition and timing of climate policy and (ii) the pace of technological change and availability of advanced technologies. To develop the scenarios, we used a suite-of-models approach that linked a computable general equilibrium energy-economy model with two macroeconomic models. The scenarios focus on Canada and the United States because of the material exposure of the Canadian financial sector to these regions. They capture the evolution of the global economy, summarized across 10 emissions-intensive sectors of the economy and across 8 distinct regions of the world. The analysis illustrated the important sectoral restructuring the Canadian and global economies may need to undertake to meet climate targets. The analysis showed that every sector contributes to the transition and that the financial impacts vary across sectors. These impacts depend on how the sectors are impacted by emissions and capital expenditures costs and on how the demand for their products is affected by the decarbonization of economies. The scenarios also shed light on the risks of significant macroeconomic impacts, in particular for commodity-exporting countries like Canada. The economic impacts for Canada are driven mostly by declines in global prices of commodities rather than by domestic policy decisions. Finally, the analysis showed that delaying climate policy action increases the overall economic impacts and risks to financial stability., En novembre 2020, la Banque du Canada a lanc�� un projet pilote en collaboration avec le Bureau du surintendant des institutions financi��res afin de mieux comprendre les risques li��s aux changements climatiques pesant sur l�����conomie et le syst��me financier. Le projet consistait notamment �� ��laborer un ensemble de sc��narios de transition climatique adapt��s au Canada pour explorer diff��rentes avenues compatibles avec l���atteinte de cibles climatiques. Les sc��narios varient selon deux grands facteurs de risque li��s �� la transition : 1) la port��e des politiques climatiques et le moment o�� elles sont adopt��es, et 2) le rythme des progr��s technologiques et la disponibilit�� des technologies de pointe. Pour ��laborer les sc��narios, nous avons utilis�� une approche fond��e sur diff��rents mod��les permettant d���associer un mod��le calculable d�����quilibre g��n��ral, ax�� sur l�����nergie et l�����conomie, �� deux mod��les macro��conomiques. Les sc��narios portent principalement sur le Canada et les ��tats-Unis en raison de l���exposition importante du secteur financier canadien �� ces r��gions. Ils prennent en compte l�����volution de l�����conomie mondiale, r��sum��e �� dix secteurs ��conomiques �� fortes ��missions et �� huit r��gions distinctes dans le monde. L���analyse montre qu���une vaste restructuration sectorielle de l�����conomie canadienne et mondiale pourrait s���av��rer n��cessaire pour assurer l���atteinte des cibles climatiques. D���abord, elle indique que tous les secteurs doivent contribuer �� la transition, laquelle pourrait avoir des incidences financi��res diff��rentes sur chacun. Ces incidences d��pendent de la mani��re dont les secteurs sont touch��s par les co��ts des ��missions et les d��penses d���investissement, et de la fa��on dont la demande de leurs produits est affect��e par la d��carbonation des ��conomies. Ensuite, il y a aussi des risques de r��percussions profondes au niveau macro��conomique, en particulier pour les pays exportateurs de produits de base, comme le Canada. Les impacts sur l�����conomie canadienne sont surtout attribuables aux baisses des prix mondiaux des produits de base. Enfin, l���analyse r��v��le que des politiques climatiques diff��r��es amplifient, globalement, les incidences ��conomiques et les risques pour la stabilit�� financi��re.

Dross from hot-dip galvanizing is an important source of pure zinc ingots and zinc oxide for use as mineral additives in animal and poultry feed. Thermodynamic calculations have shown the possibility of solving the issue of dross processing by roasting using CaCl2 and NH4Cl. The influence of the consumption of chlorinating reagents, the roasting temperature on the degree of sublimation of Pb, Fe, Ni, Cu and Cd has been investigated. It has been shown that the best results are achieved when roasting the dross with the simultaneous use of CaCl2 and NH4Cl in amounts of 6 and 15% by weight of the feed material. The optimal roasting parameters were established: T = 1000 °C, duration—60 min, air flow—0.1 L/min. Recovered pure zinc oxide composition (%) was: 0.05 Pb, 0.15 Fe, 0.06 Ni, 0.003 Cu and 0.001 Cd. The degree of sublimation of copper, nickel and iron chlorides was ~75%, with lead and cadmium at 90–98% of their initial amount in the dross.

The paper describes special aspects of using the wind power plants (wind turbines) in the power grid. The paper provides the classification and schematic presentation of AC wind turbines, analyzes the role, place and performance of wind power plants in Smart Grid systems with a large share of renewable energy sources. The authors also reviews a detailed analysis of existing AC wind turbines in this paper. Recommendations are given for how to enhance the wind power plants in smart grids in terms of reliability, and introduce the hardware used in the generation, conversion and interface systems into the existing power grid. After the wind power plants had been put online, the relevance of the Smart Grid concept for existing power grids was obvious. The execution of such projects is assumed to be financially costly, requires careful study, and development of flexible algorithms, but in some cases this may be the only approach. The analysis of using wind turbines shows that the structural configuration of wind power plants can be based on the principles known in the power engineering. The approaches may differ, not fundamentally, but in engineering considerations. it is necessary to point out that the method of controlling dual-power machines is quite comprehensive so that their wide use will face operational problems caused by the lack of highly professional specialists in electric drives. Therefore, it seems advisable to use square-cage asynchronous generators in wide applications. The paper shows that as the renewable energy sources are largely used in power grids, there is an issue of maintaining the power generation at a required level considering the variability of incoming wind energy. This results in the malfunctions in the operation of relay protection devices and emergency control automatics (RP and ECA), and the complicated control. Also, the standards of the CIS countries and regulatory documents miss the requirements for the wind turbine protections, taking into account their specialty causing the inefficient standard protective logic, which does not work correctly in a number of abnormal and emergency operating modes, and especially Smart Grid in power grids.

The kinetic parameters of the process of regeneration of a carbonate-sulfate melt with natural gas (reaction (1)) and a mixture of natural gas with air (reaction (2)) are determined in this work. It is shown that the mechanism of the process is described by a first-order equation. The activation energy of reaction (2) is four times lower than the activation energy of reaction (1). It has been established that the removal of sulfur from a carbonate-sulfate melt by bubbling with a mixture of natural gas and air can easily be carried out in the operating temperature range of an absorption column for purifying exhaust gases. The developed technology can become a practical and economical method of utilization of poor in sulfur content flue gases of thermal power plants and metallurgical enterprises., В настоящей работе определены кинетические параметры процесса регенерации карбонатно-сульфатного расплава природным газом (реакция (1)) и смесью природного газа с воздухом (реакция (2)). Показано, что механизм процесса описывается уравнением первого порядка. Энергия активации реакции (2) в четыре раза ниже энергии активации реакции (1). Установлено, что удаление серы из карбонатно-сульфатного расплава путем барботирования смесью природного газа с воздухом легко может быть осуществлено в диапазоне рабочих температур абсорбционной колонны очистки отходящих газов. Разработанная технология может стать практичным и экономичным методом утилизации бедных по содержанию серы дымовых газов ТЭС и металлургических предприятий., Горный журнал Казахстана, Выпуск 1 (189) 2021, Pages 34-40

The article considers the behavior of iron and lead compounds and their effect on the oxygen content in copper-lead mattes. The substantiation is given for the statement that the consideration of copper-lead matte in the form of a quasi-triple Cu2S PbS FeS system does not seem to be correct. When studying the thermodynamics of copper-lead mattes, it is necessary to take into account the oxygen content and the form of its presence in mattes. Such an approach allows the most comprehensive assessment of the behavior of copper, lead, arsenic and antimony in the process of converting copper-lead mattes. The oxidation mechanism of iron and lead sulfide and their mutual in- fluence on the formation of wustite and magnetite are shown based on the results of thermodynamic analysis. The Gibbs energy of the oxidation reactions of FeS and PbS was calculated.

Given its size and importance for global commodity markets, the question of how fast the Chinese economy can grow over the medium term is an important one. This paper addresses this question by examining the evolution of the supply side of the Chinese economy over history and projecting how it will evolve over the next 15 years.

This paper presents Bank of Canada staff’s current assessment of the US neutral rate, along with a newly developed set of models on which that assessment is based. The overall assessment is that the US neutral rate currently lies in a range of 1.75 to 2.75 percent., Cette étude présente l’évaluation actuelle, par le personnel de la Banque du Canada, du taux neutre aux États-Unis, ainsi qu’un nouvel ensemble de modèles sur lesquels repose cette évaluation. La Banque estime globalement que ce taux se situe en ce moment dans une fourchette allant de 1,75 à 2,75 %.

The article discusses the solubility of copper and lead in slag during mine blast smelting of intermediate products and recycled materials of lead production. The statement regarding the dependence of the solubility of copper and lead in slags from the composition of matte, slag, temperature and oxygen partial pressure is substantiated. Based on the mathematical processing of industrial and experimental data on the equilibrium of the copper-lead matte-slag-gas phase system, the dependences of the solubility of copper and lead from the composition of the slag, temperature, and PO2 are established. It was found that increase in temperature increases the solubility of copper and lead in slag. The shift of the partial pressure of oxygen towards the reducing atmosphere increases the growth of dissolved losses of lead, and vice versa, reduces the dissolved losses of copper to slag. Multiple correlation equations are generated that make it possible to predict the solubility of copper and lead in slags depending from the composition of the slag, temperature, and oxygen partial pressure, These equations can be used to control the process of mine contractile smelting of intermediate products and recycled materials of lead production.

This article is an overview of research in fault diagnosis, detection, and reconfiguration. The review particularly focuses on power electronic applications and drives. Diagnostics of systems with conventional inverter drives (CID) is considered because knowledge of fault diagnosis in CIDs can be used for application in other inverter drive topologies; therefore, several techniques of fault diagnosis and reconfiguration in CIDs are analyzed.

This article represents research on fault diagnosis of inverter electric drives. It puts more emphasis on power electronics and drives. The paper begins with the diagnostics of systems with conventional inverter drives, because knowledge of the fault diagnosis in conventional inverter can be used for its applications in other topologies of inverter drives. Therefore, the article describes several methods for troubleshooting.

Based on the relevant literature review, this paper proposes a list of the indicators of sustainable tourism. First, the overview of the sustainable development and sustainable tourism concepts are presented. Secondly, the list of the indicators of sustainable tourism is discussed, as useful tools for assessing, planning and management of sustainable tourism in a destination. Finally, it is concluded that the indicators help to understand whether tourism in a specific destination is sustainable or not, and undertake a certain measures towards sustainability.

A new modification of the least squares method (LSM) is proposed. The main idea is to consider the fitting parameters β i as independent random variables with a certain distribution density F(β1, β2, ..., β k ; φ1, ..., φ m ), which depends on a set of m experimental points φ j . Within this approach, the estimates of the parameters $$ \hat \beta _i $$ minimize squared deviations and are equivalent to means of the probability distribution $$ \hat \beta _i $$ = $$ \bar \beta _i $$ = ∫β i F(β1, β2, ..., β k ; φ1, ..., φ m )dβ1 dβ2...dβ k .

BIS interbank lending data show that the Great Recession generated large and persistent changes in the international interbank lending positions of various countries. The main objective of this study is to understand the role of changes in international interbank credit flows in transmitting shocks across borders. To accomplish this task, we needed a global structural model with an international interbank market. Our search for a suitable structural model revealed that the Bank of Canada version of the global economy model (BoC-GEM-FIN) comes closest to our needs. BoC-GEM-FIN includes region-specific interbank markets, as well as some international borrowing and lending, but abstracts from the international interbank lending. This paper describes the modifications we made in order to introduce the international interbank market into BoC-GEM-FIN. The modified model is calibrated to match the changes in international interbank lending positions and the decline in the business lending of US banks that took place after the fourth quarter of 2008. Our simulations show that the international interbank market amplifies spillover effects of demand shocks but does not systematically alter the effects of supply shocks, including those for commodities., Les données de la Banque des Règlements Internationaux relatives au financement interbancaire montrent que la Grande Récession a changé considérablement et durablement les positions de financement interbancaire internationales de plusieurs pays. La présente étude a pour principal objectif de comprendre l’incidence des changements de flux de crédit interbancaires internationaux sur la transmission transfrontière des chocs. Ainsi, il nous fallait un modèle structurel mondial intégrant un marché interbancaire international. Nous avons trouvé que la version du modèle économique mondial de la Banque du Canada – soit le modèle BoC-GEMFIN – répondait le mieux à nos besoins. Ce modèle tient compte de marchés interbancaires propres à une région ainsi que de certaines activités internationales d’emprunt et de prêt, mais fait abstraction du financement interbancaire international. Dans les lignes qui suivent, nous décrivons les modifications que nous avons apportées au modèle BoC-GEM-FIN pour y intégrer le marché interbancaire international. Nous avons calibré le modèle modifié pour faire correspondre les changements de positions de financement interbancaire internationales à la diminution du nombre de prêts consentis aux entreprises par les banques américaines qui est survenue après le quatrième trimestre de 2008. D’après nos simulations, le marché interbancaire international amplifie les effets de débordement des chocs de demande, mais ne modifie pas systématiquement les effets des chocs d’offre ni ceux des chocs liés aux produits de base.

Given its size and importance for global commodity markets, the question of how fast the Chinese economy can grow over the medium term is an important one. This paper addresses this question by examining the evolution of the supply side of the Chinese economy over history and projecting how it will evolve over the next 15 years. Using a Cobb-Douglas production function, we decompose the growth of trend GDP into those of the capital stock, labour, human capital and total factor productivity (TFP) and then forecast trend output growth out to 2030 using a bottom-up approach based on forecasts that we build for each one of these factors. Our paper distinguishes itself from existing work in that we construct a forecast of Chinese TFP growth based on the aggregation of forecasts of its key determinants. Moreover, our analysis is based on a carefully constructed estimate of the Chinese productive capital stock and a measure of human capital – based on Chinese wage survey data – that better reflects the returns to education in China. Our results suggest that Chinese trend output growth will decelerate from around 7% currently to about 5% by 2030, and are consistent with a gradual rebalancing of the Chinese economy characterized by a decline in the investment rate., Compte tenu de la taille de l’économie chinoise et de l’importance de celle-ci pour les marchés mondiaux des produits de base, il est pertinent de s’interroger sur le rythme de croissance potentiel de cette économie à moyen terme. Nous nous prêtons à l’exercice en étudiant l’évolution de l’offre dans le temps au sein de l’économie chinoise et en anticipant la progression de cette dernière dans les 15 années à venir. À l’aide d’une fonction de production Cobb-Douglas, nous décomposons la croissance tendancielle du PIB en quatre facteurs – l’accroissement du stock de capital, la hausse de la main-d’oeuvre, l’augmentation du capital humain et l’amélioration de la productivité totale des facteurs (PTF) –, puis prévoyons la croissance tendancielle de la production jusqu’en 2030 à l’aide d’une approche ascendante fondée sur nos prévisions pour chacun de ces facteurs. Notre article se distingue des travaux actuels en ce que nous construisons une prévision de la croissance de la PTF chinoise à partir de l’agrégation de prévisions concernant ses principaux déterminants. Par ailleurs, notre analyse repose sur une estimation rigoureusement construite du stock de capital productif en Chine et sur une mesure du capital humain – d’après des données d’enquête sur les salaires chinois – qui tient mieux compte des rendements de l’éducation dans ce pays. Nos résultats donnent à penser que la croissance tendancielle de la production chinoise ralentira pour passer d’environ 7 % actuellement à 5 % d’ici 2030, et cadrent avec un rééquilibrage progressif de l’économie chinoise, marqué par une baisse du taux d’investissement.

We propose a simple approach to using value-at-risk (VaR) to measure market risk within the equity inventory of a market making entity, a task which presents several challenges specific to the market making function. Market makers constantly stand ready to buy and sell shares to market participants. In doing so, they inevitably maintain the inventory of shares, a portfolio of sorts, subject to market risk. VaR is a standard tool for measuring the market risk in investment portfolios, so a variety of calculation techniques have been developed over the years. However, the application of VaR to market making inventories requires a few adjustments, for unlike the typical investment portfolio these inventories change rapidly, as if they were rebalanced intra-day. Moreover, the number of unique tickers in the inventory for a given day may routinely list thousands of securities. As a result, at any moment in an inventory there could be hundreds of items with missing historical price data, which makes challenging the application of even the simplest VaR methods. The approach proposed in this paper deals with the rapidly rebalancing portfolio and missing data issues inherent in market making equity portfolios by rescaling portfolio weight to allow for the application of well-known VaR techniques to very large inventories.

Consider randomly picked points inside the n-dimensional unit hypersphere centered at the origin of the Cartesian coordinate system. The Cartesian coordinates of the points are random variables, which form an n-dimensional vector for each point. Observing only the x-coordinate I obtained its probability density function (PDF). I show that it is related to the Gaussian distribution: in limit its companion PDF?? converges to the PDF of the standard normal distribution., 7 pages, 3 figures

I studied the convergence of regional house prices to national prices in USA by analyzing time-series of house price indices of 9 Census Divisions. I found the evidence of the convergence in some parts of the country using asymmetric unit root tests. The fact that the evidence of the convergence is not present in large parts of the country raises an issue of execution and interpretation of results of Federal Reserve Bank's annual stress testing of the US banking system., Comment: 38 pages, 7 tables, 30 figures

Consider error terms x(i) of a moving average process MA(q), where x(i)=e(i) + e(i-1)+...+e(i-q) and e(i) - independent identically distributed (i.i.d.) random variables. We recognize a term x(i) as a local maximum if the following condition holds true: x(i-1) < x(i) > x(i+1). If the local maximum x(i) is followed by the next local maxiumum x(k), then d=k-i is the distance between local maxima. The distances d(j) themselves are random vriables. In this paper we study the probability distribution of distances d(j). Particularly, we show that for any q>0 mean distance E[d(j)]=4 and asymptotically the variance is also equal to 4., Updated references, corrected equations, language edited. 4 pages

Bu çalışmada, Samsun'daki Eti-Bakır Tesisinin Outokumpu tip flaş izabesinden alınan data, Visual Basic bilgisayar programı uygulaması ile Excel baglantısı kullanıldı. Eti-Bakır tesisinde kullanılan flaş izabe, metalik sülfür konsantrelerin ergitilmesi için kullanılan pirometallurjik yöntemdir. Fabrikada, bakır flaş izabesi için hava ile üflenen ince ve kuru bakır sülfür konsantre karışımları, silika flaks ve linyit ana yakıt olan doğal gaz ile birlikte kullanılmaktadır. Fırının temel ürünü ergimiş mat ve 0.5-2% civarında bakır içeren curuftur. Bakırın geri kazanımı için curuf, flotasyon işlemine tabi tutulur. Flaş fırınından çıkan 8-12% hacmindeki SO2 gazı H2SO4'e dönüştürülür. Fabrikanın malzeme ve ısı dengesini kullanılarak yazılan program, flaş fırınındaki tüketilen oksijenle zenginleştirilmiş hava, yakıt ve linyitin optimizasyonu için kullanıldı. In this study the data taken from Outokumpu type Flash smelter of Eti-Bakır Plant (Samsun, Turkey) was used to write a computer program in Visual Basic with interface to Excel. Flash smelting is the pyrometallurgical process for smelting metal sulfide concentrates, used in Eti-Bakır plant. In this plant, copper flash smelting consists of blowing fine, dried copper sulfide concentrate mixtures, silica flux, lignite with air into the furnace and natural gas as main fuel. The molten matte is the principal product of the furnace and slag contains 0.5-2% Cu. It is sent to a slag treatment (flotation) process for Cu recovery. This flash furnace off-gas contains from 8-12 volume % SO2 which is fixed as H2SO4. Written program was used to optimize the consumption of oxygen enriched air, fuel and lignite in this Flash Smelter by making material and heat balance of the plant. 143

We analyze numerical stability of a recursive computation scheme of present value (PV) amd show that the absolute error increases exponentially for positive discount rates. We show that reversing the direction of calculations in the recurrence equation yields a robust PV computation routine., 6 pages, 2 tables

There is a sequence of random numbers x1,x2, ..., xn and so on. Numbers are independent of each other, but all numbers are from the same continuous distribution. If x1 < x2 > x3, then x2 is a local maximum. Here, we show that the probability mass function (PMF) of idstribution of distances between local maxima is non-parametric and the same for any probability distribution of random numbers in the sequence, and that the average distance is exactly 3. We present a method of computation of this PMF and its table for distances betwen 2 and 29. This PMF is confirmed to match distance distributions of sample random number sequences, which were created by pseudo-random number generators or obtained from "true" random number sources., 8 pages, 1 figure, 2 tables. This version updates a reference to an earlier work by Oshanin, and corrects a typo in equation 3.1 (thanks to Eduardo D. da Costa for noticing it)