Exchange Positions Research Articles

Transient characteristics of typical design basis accidents in integrated small reactor NHR200-II using RELAP5 model

The development of advanced integrated small reactors is one of the most important trends in nuclear engineering nowadays, the NHR200-II reactor proposed by Tsinghua university has also undergone several iterations of improvement. The increased thermal–hydraulic parameters mean that the design-basis accidents need to be reanalyzed, of which three typical scenarios are chosen as benchmarks and simulated with the complete RELAP5-model. The small break loss-of-coolant accident, the pump-shaft-stuck accident and the heat-transfer-tube-rupture in main heat exchanger accident were assessed systematically and showed good agreement with previous research. The characteristics like the transient flow rate at the break, the moment of inertia of circuit pump and the position of the main heat exchanger were examined, different control variables mainly affect the sequence of trigger actions rather than overall thermal–hydraulic parameters. The results demonstrate that the reactor core can be cooled sufficiently throughout all transient conditions and be flooded with coolant.

Matrix Non-Structural Model and Its Application in Heat Exchanger Network without Stream Split

Heat integration by a heat exchanger network (HEN) is an important topic in chemical process system synthesis. From the perspective of optimization, the simultaneous synthesis of HEN belongs to a mixed-integer and nonlinear programming problem. Both the stage-wise superstructure (SWS) model and the chessboard model are the most widely adopted and belong to structural models, in which a framework is assumed for stream matching, and the global optimal solution outside its feasible domain may be defined by the framework. A node-wise non-structural model (NW-NSM) is proposed to find more universal stream matching options, but it requires a mass of structural variables and extra multiple correction strategies. The aim of this paper is to develop a novel matrix non-structural model (M-NSM) for HEN without stream splits from the perspectives of global optimization methods and superstructure models. In the proposed M-NSM, the heat exchanger position order is quantized by matrix elements at each stream, and a HEN structure is initialized by the random generation of matrix elements. An approach for solving HEN problems based on a matrix real-coded genetic algorithm is employed in this model. The results show that M-NSM provides more flexibility to expand the search region for feasible solutions with higher efficiency than previous models.

The Rubiks Cubes in Group Theory

This paper expounds the basic concept of group theory and its application in Rubiks Cube transformation and restoration formula. The different states of the magic cube are regarded as the elements of the magic cube group, and the set generated by six basic operations is equivalent to the homomorphism of the magic cube group for analysis, from the mathematical characteristics of the permutation group to some practical examples. The collection of possible states of Rubik's Cube is a group, called Rubik's Cube Group, which can be analyzed with the knowledge of group theory. The essence of the magic cube group is the subgroup of the substitution group. There are six basic operations of the magic cube. The combination of basic operations can only produce even pairs of blocks to exchange positions or flip directions at the same time. Therefore, there are some restrictions on the transformation of the magic cube. Some practical examples give some ideas for creating the magic cube formula.

Catalytic Oxidation of VOC over Cobalt-Loaded Hierarchical MFI Zeolite

The zeolites ZSM-5 with different Si/Al ratios were modified with a buffer solution of HF and NH4F. This acidic treatment led to the obtaining of a material with secondary mesoporosity. The deposition of cobalt from an aqueous solution of cobalt acetate on the surface of treated samples generates the formation of different cobalt oxide species: bulk-like Co3O4 phases strongly interacting with the support, Co2+ in ion exchange positions (γ and β sites) and silicate-like phases. The mechanism of cobalt silicate phase formation is proposed here and includes a replacement of silanol groups and the bridging hydrogens by Co and the inclusion of the Co atoms in tetrahedral framework positions. The catalysts, obtained through use of the treated ZSM-5, exhibit higher activity in the reactions of propane, and n-hexane completes oxidation compared with the catalyst samples containing un-treated zeolite. Both the finer dispersion of metal oxide particles on the hierarchical sample and the presence of secondary mesoporosity improve the effectiveness of the active phase utilization via access to larger number of active sites.

Hydrodynamics for the ABC model with slow/fast boundary

In this article, we consider the ABC model in contact with slow/fast reservoirs. In this model, there is one particle per site, which can be of type α∈{A,B,C} and particles exchange positions in the discrete set of points {1,…,N−1} with a rate which is weakly asymmetric and depends on the type of particles involved in the exchange mechanism. At the boundary points x=1,N−1 particles can be injected or removed, and the rate at which this happens depends on the type of particles involved. We prove the hydrodynamic limit, in the diffusive time scale, given by a system of non-linear coupled equations with several boundary conditions, that depend on the strength of the reservoir’s action.

Numerical investigation of extracted position characteristics in porous media with lean methane and air premixtures combustion

Hydrogen production through steam generated from low-grade fuel recovery is considered a prospective method. To maximize the energy recovery, the influence of the heat exchanger position on the heat extraction stability of lean methane-air premixtures combustion in a porous burner has been numerically explored. The extracted position coefficient (EPC) is defined and a heat extraction model is validated through the experimental findings. It is shown that extracted position has a significant influence on the temperature profile, heat transfer capacity, heat loss as well as heat recovery rate. When the EPC is lower than 0.18, the filtration burner shows worse stability with great heat loss, the heat transfer behavior of the heat exchange tubes is severely weakened and heat recovery efficiency is merely about 13%. The optimal heat recovery position is recommended in the EPC range of 0.36–0.55, which has shown excellent heat extraction performance and accelerated the process of acquiring a quasi-steady state. Within this EPC range, the fluctuation of outlet temperature difference can be stabilized within 0.2 K, which maximizes the heat flux of heat exchangers, and heat recovery efficiency of about 70%–89% recovered with a concentration of 0.4%–0.8%.

ФОРМУВАННЯ ФІНАНСОВО ПЕРСПЕКТИВНОЇ ІДЕЇ: БІРЖОВЕ ПІДПРИЄМНИЦТВО

Over the past two decades, the exchange environment has changed significantly, digitized, become more flexible and moved to other platforms. Technological, low-cost trading platforms contributed to intensifying competition between traditional exchanges. Conventional cooperative exchanges had neither the structural flexibility nor the financial agility to actively compete with new trading platforms. Digitization of exchanges leads to the emergence of new regulatory problems; therefore it is important that regulators and exchange management clearly understand the process of forming a financially promising idea and exchange position, are able to assess new risks and effectively solve them. The purpose of the study is to develop an approach to determining the value of the process of initiation, categorization and implementation of financially promising ideas and projects from the point of view of service on exchange platforms and its introduction as an evaluation of stock market instruments. Scientific publications and monographic editions, magazine articles and materials of scientific and practical conferences became the methodological basis of the research. Content analysis of scientific periodicals was used during the research; comparative critical analysis of existing approaches and methods of analysis of financial stability and tax burden; analysis of economic activity of enterprises in the aerospace industry; statistical methods of analysis. The main hypothesis of the study was the assumption of the possibility of forming an approach to determining the meaning of the process of initiation, categorization and implementation of financially promising ideas and projects from the point of view of service on exchange platforms and introduction as stock market tools. Presenting main material. The article examines the main aspects of the formation of an approach to determining the meaning of the process of initiation, categorization and implementation of financially promising ideas on stock exchanges. It is emphasized that financial ecology has significantly affected the exchange environment, forcing exchanges to review their roles and change the policy of their strategies regarding the formation of financially promising ideas. The stock exchange is presented as a commercial organization that produces a single product – price. The originality and practical significance is defined in the development of a methodical approach to determining the value of the process of initiation, categorization and implementation of financially promising ideas and projects from the point of view of service on exchange platforms and its introduction as an evaluation of stock market instruments. Conclusions and prospects for further research. The study analyzed the transformation of the stock exchange from the market model to the enterprise model. The role of the main functions of the stock exchange was reviewed and an analysis of the formation of an approach to determining the meaning of the process of initiation, categorization and implementation of financially promising ideas and projects from the point of view of service on stock exchange platforms and its introduction as an evaluation of stock market instruments was carried out

Cobalt on dealuminated-Siβ as a catalyst for the oxidative dehydrogenation of propane

The present work aims at investigating the oxidative dehydrogenation of propane (ODHP) catalytic properties of Co species supported on a Siβ zeolitic support. The Co2+ species incorporated in the silanol nests created by dealumination of a HAlSiβ pristine support (Co-Siβ) appeared to be about 4 times more active (3.1 × 10-3 s-1) compared with that in exchange position of HAlSiβ (0.9 ×10-3 s-1) for the formation of propene at 400 °C. The turn over frequency of the Co-Siβ samples are found to be greater than or equal to those reported in most of the earlier studies performed with Co-containing materials to date and to be about 7 times greater than that of V-Siβ materials (0.4 ×10-3 s-1) from an earlier study, which illustrates the superiority of Co-Siβ over V-Siβ for the ODHP reaction. Maximum incorporable content of Co as Co-Siβ is dictated by the amount of removable Al.

Metal-Organic Frameworks as Electrocatalysts.

Transition metal complexes are well-known homogeneous electrocatalysts. In this regard, metal-organic frameworks (MOFs) can be considered as an ensemble of transition metal complexes ordered in a periodic arrangement. In addition, MOFs have several additional positive structural features that make them suitable for electrocatalysis, including large surface area, high porosity, and high content of accessible transition metal with exchangeable coordination positions. The present review describes the current state in the use of MOFs as electrocatalysts, both as host of electroactive guests and their direct electrocatalytic activity, particularly in the case of bimetallic MOFs. The field of MOF-derived materials is purposely not covered, focusing on the direct use of MOFs or its composites as electrocatalysts. Special attention has been paid to present strategies to overcome their poor electrical conductivity and limited stability.

Metal–Organic Frameworks as Electrocatalysts

AbstractTransition metal complexes are well‐known homogeneous electrocatalysts. In this regard, metal–organic frameworks (MOFs) can be considered as an ensemble of transition metal complexes ordered in a periodic arrangement. In addition, MOFs have several additional positive structural features that make them suitable for electrocatalysis, including large surface area, high porosity, and high content of accessible transition metal with exchangeable coordination positions. The present review describes the current state in the use of MOFs as electrocatalysts, both as host of electroactive guests and their direct electrocatalytic activity, particularly in the case of bimetallic MOFs. The field of MOF‐derived materials is purposely not covered, focusing on the direct use of MOFs or its composites as electrocatalysts. Special attention has been paid to present strategies to overcome their poor electrical conductivity and limited stability.

CsxCo/Na-MOR Coating on Ceramic Monoliths for Co-Adsorption of Hydrocarbons Mixture and Selective Catalytic Reduction of NOx

In this work, ceramic monoliths were coated with powders based on exchanged Cs and/or Co cations in Na-mordenite (MOR) zeolite. SEM images showed that zeolite particles fill the macropores of cordierite walls and form a continuous layer of approximately 40 µm with good adherence. XPS analysis revealed that Co and Cs are present on the film surface solely as Co2+ and Cs+ at exchange positions in zeolite. The monolithic structures were evaluated for the butane-toluene co-adsorption and SCR of NOx with hydrocarbon mixture as the reducing agent. The presence of alkali metal cations in the zeolitic lattice favored the adsorption capacity of both hydrocarbons, while cobalt cations provoked a decrease in the adsorbed amounts due to its weak interaction with the HCs. Breakthrough curves of butane adsorption showed a roll-up phenomenon, associated with a competitive adsorption effect generated from toluene presence. In the desorption process, it was observed that adsorbed toluene hindered the butane diffusion through mordenite channels, which released at higher temperatures (above 250 °C). Cs2CoM and Cs7CoM monoliths were more active than the CoM monolith for NO-SCR. The presence of Cs cations close to Co cations increased the hydrocarbons concentration around active sites at high temperatures, according to TPD results, promoting the reduction activity of NO.

����� �� ������ �������� ������ �����

Abstract. Introduction. The activity of banks in foreign exchange markets, which consists in the management of assets and liabilities in foreign currency and in bank metals, is associated with currency risks (one of the elements of market risk), which arise in connection with the use of various currencies and bank metals during conducting banking operations. Risk means the uncertainty associated with the occurrence of any event or its consequences. The continuous functioning of the foreign exchange market is its main feature, which leads to the fact that a bank that has an open position in foreign currency is exposed to currency risk even when it is not working. Under such circumstances, the analysis and assessment of currency risks in the bank becomes very relevant, the results of which will ensure the creation of conditions for its stable and efficient functioning. Purpose. The purpose of the work is the analysis and assessment of the bank's currency risk. Results. The article examines the nature and types of currency risk, analyzes the structure and dynamics of currency assets and liabilities on various grounds. Also, the work identifies the risk of currency operations of JSC "Ukrsibbank" and draws relevant conclusions. Conclusions. The work draws the following conclusions: in the composition of foreign currency assets, a significant share of loans to legal entities is almost 33% and other currency assets - almost 62%, the lowest share is loans to individuals and funds in other banks; the dynamics of all currency assets is not uniform, there is a clear growth trend only in other currency assets, and only through them the bank increases currency assets in general; the largest share in the bank's monetary assets and liabilities is made up of US dollars and Euros; in terms of the number of currencies that the bank uses in foreign exchange operations, the currency portfolio is not diversified, which causes additional risk. Therefore, the bank's foreign exchange risk management policy can be assessed as positive, since banks, in contrast to risks, create reserves for assets from conversion into the reporting currency, in recent years have followed the norms of the foreign exchange position and used favorable trends in exchange rate changes in the formation of foreign currency assets and liabilities.

Neo-splicetopes, new potential targets in tumor T cell therapy? Pros and Caveats

Adoptive T cell therapy is by now the most effective immunotherapy, being able to eradicate large established tumors in selected clinical situations. Through invention of T cell receptor (TCR) gene therapy, the grafting of new antigen specificities onto patients’ T cells, it has become feasible. As such, tumor specific somatic mutations occurring within MHC I epitopes are attractive prime candidates for T cell receptor (TCR) gene therapy. However, not every amino acid exchange within a putative tumor epitope will result in the generation of a high affinity MHC class I epitope suitable for TCR therapy. In fact, depending on the position of the amino acid exchange within the epitope the mutant residue can dramatically reduce MHC class I binding affinity and thereby its therapeutic use. Therefore, identification of neo-splicetopes (i.e. spliced epitopes generated from a tumor specific neoantigen) may be of value particularly in those cases in which recurrent tumor specific mutations do not result in the formation of a high affinity non-spliced neo-epitope. Furthermore, identification of different neosplicetope derived from the same neoantigen has the potential to expand the HLA-1 haplotype diversity. We will present experimental data describing the identification and immunological verification of new spliced mutant tumor specific epitopes in those neo-antigens which can otherwise only be poorly targeted and discuss arguments in favour of our approach but also point out existing caveats.

Authoritative performances of care in home exchange

This research examines the position of home exchange within the sharing economy. Drawing on in-depth qualitative research, we adopt the lens of authoritative performances to explore how home exchangers resolve contradictions between competing endeavours. Taking a pluralistic view, our findings have revealed that home exchangers are entrepreneurial in the meanings they attach to their homes. However, this is softened by authoritative performances of care that replace impersonal exchange with interpersonal relationships of reciprocity and mutual trust. Our findings also offer further contributions by exploring how home exchangers experience the dichotomies of familiar and unfamiliar in tourism and the absent and present host.

The Performance of the U Shape Double pipe heat exchanger under effect of using Active Techniques.

The main aim from this research experimentally studied the effect of external power effect like use the active technique which is represented as an air bubble injection on shell side of of U shape double pipe heat exchanger and in this investigations was used a suitable U shape heat exchanger with different position angle of the U shape Exchanger like position (U shape , ? Inverse U shape ) in additionally used a system which has all the equipments that measuring flow rates and parameters, the vortex generation due to the curvature of bending shell and tube has strong effect to increase the performance of exchanger. The results with this injection inside the shell side demonstrated that the optimize position of exchanger with best performance of parameter was with (?) Inverse and the exchanger enhancement was (24.4%) due to the different shape of diffuser which was used it with inverse U shape exchanger. the air bubble injection as active technique it suggested that the effect cause by the bubble increment the agitation of flow and due to the motion of fluid and air as mixing turbulence flow motion and increased the heat transfer rate and performance parameter of exchanger .

Penerapan Algoritma Bayesian Regulation untuk Estimasi Posisi Cadangan Devisa Indonesia

Foreign exchange reserves need to be predicted because it is a significant monetary indicator to show the strength or weakness of a country's economic fundamentals. Therefore, the purpose of this study is to estimate the position of Indonesia's foreign exchange reserves at the end of 2022 and 2023 so that the government has benchmarks and information in determining the right economic policy so that the position of foreign exchange reserves remains stable. The estimation algorithm used in this study is the Bayesian Regulation algorithm, one of the Artificial Neural Network algorithms. The research data used is data on the position of Indonesia's foreign exchange reserves (US$ million) obtained from the economic reports of Bank Indonesia. This research will be analyzed using three network architecture models 4-9-1, 4-18-1, and 4-27-1. Based on the analysis of the three models used, the results show that the 4-27-1 model is the best because it has a lower Mean Square Error (MSE) value of 0.00203297. Another benchmark is seen from more minor epochs (iterations) and faster times than the other two models, even though they both produce a 100% accuracy rate. Thus, it can be concluded that the Bayesian Regulation algorithm is good enough to estimate the position of foreign exchange reserves using the 4-27-1 model. Based on the prediction results, the part of Indonesia's foreign exchange reserves at the end of 2022 and 2023 slightly decreased compared to 2021.

Ni-H-Beta Catalysts for Ethylene Oligomerization: Impact of Parent Cation on Ni Loading, Speciation, and Siting

Ni-H-Beta catalysts for ethylene oligomerization (EO) were prepared by ion exchange of NH4-Beta and H-Beta zeolites with aqueous Ni(NO3)2 and characterized by H2-temperature-programmed reduction (TPR), NH3-temperature-programmed desorption (TPD), and diffuse-reflectance infrared Fourier-transform spectroscopy (DRIFTS). Quadruple exchange of NH4-Beta at 70 °C resulted in 2.5 wt.% Ni loading corresponding to a Ni2+/framework aluminum (FAl) molar ratio of 0.52. [NiOH]+ and H+ are the primary charge-compensating cations in the uncalcined catalyst, as evidenced by TPR and DRIFTS. Subsequent calcination at 550 °C in air yielded a Ni-H-Beta catalyst containing primarily bare Ni2+ ions bonded to framework oxygens. Quadruple exchange of H-Beta at 70 °C gave 2.0 wt.% Ni loading (Ni2+/FAl = 0.41). After calcination at 550 °C, the resulting Ni-H-Beta catalyst comprises a mixture of bare Ni2+ ions: [NiOH]+ and NiO species. The relative abundance of [NiOH]+ increases with the number of exchanges. In situ pretreatment at 500 °C in flowing He converted the [NiOH]+ species to bare Ni2+ ions via dehydration. The bare Ni2+ ions interact strongly with the Beta framework as evidenced by a perturbed antisymmetric T-O-T vibration at 945 cm−1. DRIFT spectra of CO adsorbed at 20 °C indicate that the Ni2+ ions occupy two distinct exchange positions. The results of EO testing at 225 °C and 11 bar (ethylene) suggested that the specific Ni2+ species initially presented (e.g., bare Ni2+, [NiOH]+) did not significantly affect the catalytic performance.

Analisis Determinan Cadangan Devisa Indonesia Tahun 1991-2020

Foreign exchange reserves are the total value of international assets controlled by the government as the monetary authority. Foreign exchange reserves can be used to finance balance of payments imbalances or achieve monetary stabilization by intervening in the foreign exchange market. The position of Indonesia's foreign exchange reserves fluctuates greatly, there are many factors that can influence it, both from within and outside the country. This study will analyze the effect of the exchange rate, composite stock price index, world oil prices, net exports, and foreign debt on the position of Indonesia's foreign exchange reserves from 1991 to 2020 using Ordinary Least Square regression analysis. The regression results show that world oil prices, net exports, and foreign debt have a positive effect on foreign exchange reserves, while the exchange rate has a negative effect on foreign exchange reserves. Meanwhile, the composite stock price index was found to have no effect on the position of Indonesia's foreign exchange reserves.

Enhanced boron modified graphitic carbon nitride for the selective photocatalytic production of benzaldehyde

Graphitic carbon nitride is a non-metal photocatalyst easily prepared from nitrogen organic compounds through green synthesis processes that do not require the use of solvents. This work proposes the use of boron to modify the layered g-C3N4 structure by incorporating B to induce defects aimed at the enhancement of the photocatalytic activity. Boron-modified graphitic carbon has been obtained using elemental B and NaBH4 as precursors. The XRD and FTIR characterization results suggest that the C and N positions of g-C3N4 can be replaced by B, resulting in a layered modified structure in which the tri-s-triazine units are altered. The exchange of B atoms differed from the boron precursor according to the analysis of the chemical properties of the surface. Thus, the elemental B had a preference to exchange positions with N atoms, whereas the use of NaBH4 led to the substitution of B into the C positions. This difference considerably affected the photocatalytic activity during the selective oxidation of benzyl alcohol. The sample modified with NaBH4 led to the highest oxidation rate and selectivity linked to a lesser recombination effect than the other samples according to photoluminescence tests. This work provides evidence about the convenience of the selection of precursors during the modification of g-C3N4. The photon absorbance rate was determined for the estimation of the quantum yield. Although the photon absorbance rate was quite similar in all the cases, the different registered kinetics led to a maximum quantum efficiency of 0.15% for NaBCN.

Bucharest Stock Exchange development between 1995 and 2020. From frontier to secondary emerging market

"The current paper presents and discuss the evolution of Bucharest Stock Exchange over the past 25 years since the re-establishment of this institution. The study also discuss the upgrade and re-classification of the Romanian capital market as a secondary emerging market by the index provider FTSE Russel. Further, it presents Bucharest Stock Exchange position among the security exchanges of the former communist countries, which became member of the European Union. Also, some influences resulting from the implementation of European Union directives in financial sector are discussed The paper concludes showing that Bucharest Stock Exchange still has a long road ahead until it will fulfill the conditions to be re-classified as a full emerging market by the other two global index providers, MSCI Barra and Standard and Poor’s. Key Words: security market, frontier market, secondary emerging market JEL Classification: G10, G19 "