Search results for: ion exchange
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 1510

Search results for: ion exchange

1450 Tuning of Indirect Exchange Coupling in FePt/Al₂O₃/Fe₃Pt System

Authors: Rajan Goyal, S. Lamba, S. Annapoorni

Abstract:

The indirect exchange coupled system consists of two ferromagnetic layers separated by non-magnetic spacer layer. The type of exchange coupling may be either ferro or anti-ferro depending on the thickness of the spacer layer. In the present work, the strength of exchange coupling in FePt/Al₂O₃/Fe₃Pt has been investigated by varying the thickness of the spacer layer Al₂O₃. The FePt/Al₂O₃/Fe₃Pt trilayer structure is fabricated on Si <100> single crystal substrate using sputtering technique. The thickness of FePt and Fe₃Pt is fixed at 60 nm and 2 nm respectively. The thickness of spacer layer Al₂O₃ was varied from 0 to 16 nm. The normalized hysteresis loops recorded at room temperature both in the in-plane and out of plane configuration reveals that the orientation of easy axis lies along the plane of the film. It is observed that the hysteresis loop for ts=0 nm does not exhibit any knee around H=0 indicating that the hard FePt layer and soft Fe₃Pt layer are strongly exchange coupled. However, the insertion of Al₂O₃ spacer layer of thickness ts = 0.7 nm results in appearance of a minor knee around H=0 suggesting the weakening of exchange coupling between FePt and Fe₃Pt. The disappearance of knee in hysteresis loop with further increase in thickness of the spacer layer up to 8 nm predicts the co-existence of ferromagnetic (FM) and antiferromagnetic (AFM) exchange interaction between FePt and Fe₃Pt. In addition to this, the out of plane hysteresis loop also shows an asymmetry around H=0. The exchange field Hex = (Hc↑-HC↓)/2, where Hc↑ and Hc↓ are the coercivity estimated from lower and upper branch of hysteresis loop, increases from ~ 150 Oe to ~ 700 Oe respectively. This behavior may be attributed to the uncompensated moments in the hard FePt layer and soft Fe₃Pt layer at the interface. A better insight into the variation in indirect exchange coupling has been investigated using recoil curves. It is observed that the almost closed recoil curves are obtained for ts= 0 nm up to a reverse field of ~ 5 kOe. On the other hand, the appearance of appreciable open recoil curves at lower reverse field ~ 4 kOe for ts = 0.7 nm indicates that uncoupled soft phase undergoes irreversible magnetization reversal at lower reverse field suggesting the weakening of exchange coupling. The openness of recoil curves decreases with increase in thickness of the spacer layer up to 8 nm. This behavior may be attributed to the competition between FM and AFM exchange interactions. The FM exchange coupling between FePt and Fe₃Pt due to porous nature of Al₂O₃ decreases much slower than the weak AFM coupling due to interaction between Fe ions of FePt and Fe₃Pt via O ions of Al₂O₃. The hysteresis loop has been simulated using Monte Carlo based on Metropolis algorithm to investigate the variation in strength of exchange coupling in FePt/Al₂O₃/Fe₃Pt trilayer system.

Keywords: indirect exchange coupling, MH loop, Monte Carlo simulation, recoil curve

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1449 The Nexus between Country Risk and Exchange Rate Regimes: A Global Investigation

Authors: Jie Liu, Wei Wei, Chun-Ping Chang

Abstract:

Using a sample of 110 countries over the period 1984-2013, this paper examines the impacts of country risks on choosing a specific exchange rate regime (first by utilizing the Levy-Yeyati and Sturzenegger de facto classification and then robusting it by the IMF de jure measurement) relative to other regimes via the panel multinomial logit approach. Empirical findings are as follows. First, in the full samples case we provide evidence that government is more likely to implement a flexible regime, but less likely to adopt a fixed regime, under a low level of composite and financial risk. Second, we find that Eurozone countries are more likely to choose a fixed exchange rate regime with a decrease in the level of country risk and favor a flexible regime in response to a shock from an increase of risk, which is opposite to non-Eurozone countries. Third, we note that high-risk countries are more likely to choose a fixed regime with a low level of composite and political risk in the government, but do not adjust the exchange rate regime as a shock absorber when facing economic and financial risks. It is interesting to see that those countries with relatively low risk display almost opposite results versus high-risk economies. Overall, we believe that it is critically important to account for political economy variables in a government’s exchange rate policy decisions, especially for country risks. All results are robust to the panel ordered probit model.

Keywords: country risk, political economy, exchange rate regimes, shock absorber

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1448 ASEAN Our Eyes: A Strategic Information Exchange Platform on Counter-Terrorism

Authors: Nila Febri Wilujeng, Helda Risman

Abstract:

Enjoying stable security within its region for the last 50 years, ASEAN nowadays contends with the global context emerging dynamically, which brings about multidimensional challenges and threats such as terrorism, radicalism, armed rebellion, hijacking, and other non-traditional threats. Dealing with these circumstances, ASEAN member states tighten its capacity by enhancing regional cooperation and strategic information exchange among ASEAN member states so-called ASEAN Our Eyes. This initiative adopted for the sake of forestalling any possible threat posed by violent extremism, radicalization, and terrorism through timely strategic information exchange among ASEAN member states. By using qualitative method, this paper will utilize regional security complex and international cooperation theories in analyzing the process to examine ASEAN Our Eyes based on its terms of reference. As a result, it portrays that ASEAN Our Eyes is able to undermine the gaps in the realm of strategic information exchange in monitoring the movement of violent extremism, radicalism, foreign terrorist fighters, and crime-terror nexus. However, it remains premature as a strategic measure to encounter those threats in the years to come.

Keywords: regional cooperation, counter-terrorism, ASEAN our eyes, strategic information exchange

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1447 Message Framework for Disaster Management: An Application Model for Mines

Authors: A. Baloglu, A. Çınar

Abstract:

Different tools and technologies were implemented for Crisis Response and Management (CRM) which is generally using available network infrastructure for information exchange. Depending on type of disaster or crisis, network infrastructure could be affected and it could not be able to provide reliable connectivity. Thus any tool or technology that depends on the connectivity could not be able to fulfill its functionalities. As a solution, a new message exchange framework has been developed. Framework provides offline/online information exchange platform for CRM Information Systems (CRMIS) and it uses XML compression and packet prioritization algorithms and is based on open source web technologies. By introducing offline capabilities to the web technologies, framework will be able to perform message exchange on unreliable networks. The experiments done on the simulation environment provide promising results on low bandwidth networks (56kbps and 28.8 kbps) with up to 50% packet loss and the solution is to successfully transfer all the information on these low quality networks where the traditional 2 and 3 tier applications failed.

Keywords: crisis response and management, XML messaging, web services, XML compression, mining

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1446 The Fight against Pollution of Heavy Metals

Authors: K. Menad, A. Feddag, M. A. Hassnaoui

Abstract:

We are living in a time and in a world heavily polluted. In the list of the great dangers awaiting the man can be placed on top of the list pollution by heavy metals: lead, mercury, cadmium, etc. Fatigue, Depression, Thyroid disorder, Alzheimer's, Parkinson's, Cancer, are some of the health problems caused by heavy metal pollution. The environmental protection has long since become a major political and economic issue. Among the priorities, include safeguarding water resources. All countries of the world are concerned either because they lack water or because they pollute it. There are several ways to remove these heavy metals; ion exchange by zeolites is one of these ways, which our work is based on. Zeolites were among the main clean up materials by either adsorption, ion exchange and catalysis. Lead and cadmium, heavy metals, is one of the main dangers fulminate the flora and fauna of our small planet, so many resources are deployed to remedy them. The elimination of lead and cadmium by ion exchange has been extensively studied. However, exchange capacity of more and larger formed a major challenge for researchers and industry.

Keywords: composite, ion excahnge, zeolite LTA, zeolite x

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1445 Implication of the Exchange-Correlation on Electromagnetic Wave Propagation in Single-Wall Carbon Nanotubes

Authors: A. Abdikian

Abstract:

Using the linearized quantum hydrodynamic model (QHD) and by considering the role of quantum parameter (Bohm’s potential) and electron exchange-correlation potential in conjunction with Maxwell’s equations, electromagnetic wave propagation in a single-walled carbon nanotubes was studied. The electronic excitations are described. By solving the mentioned equations with appropriate boundary conditions and by assuming the low-frequency electromagnetic waves, two general expressions of dispersion relations are derived for the transverse magnetic (TM) and transverse electric (TE) modes, respectively. The dispersion relations are analyzed numerically and it was found that the dependency of dispersion curves with the exchange-correlation effects (which have been ignored in previous works) in the low frequency would be limited. Moreover, it has been realized that asymptotic behaviors of the TE and TM modes are similar in single wall carbon nanotubes (SWCNTs). The results show that by adding the function of electron exchange-correlation potential lead to the phenomena and make to extend the validity range of QHD model. The results can be important in the study of collective phenomena in nanostructures.

Keywords: transverse magnetic, transverse electric, quantum hydrodynamic model, electron exchange-correlation potential, single-wall carbon nanotubes

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1444 Kinetic Modeling of Transesterification of Triacetin Using Synthesized Ion Exchange Resin (SIERs)

Authors: Hafizuddin W. Yussof, Syamsutajri S. Bahri, Adam P. Harvey

Abstract:

Strong anion exchange resins with QN+OH-, have the potential to be developed and employed as heterogeneous catalyst for transesterification, as they are chemically stable to leaching of the functional group. Nine different SIERs (SIER1-9) with QN+OH- were prepared by suspension polymerization of vinylbenzyl chloride-divinylbenzene (VBC-DVB) copolymers in the presence of n-heptane (pore-forming agent). The amine group was successfully grafted into the polymeric resin beads through functionalization with trimethylamine. These SIERs are then used as a catalyst for the transesterification of triacetin with methanol. A set of differential equations that represents the Langmuir-Hinshelwood-Hougen-Watson (LHHW) and Eley-Rideal (ER) models for the transesterification reaction were developed. These kinetic models of LHHW and ER were fitted to the experimental data. Overall, the synthesized ion exchange resin-catalyzed reaction were well-described by the Eley-Rideal model compared to LHHW models, with sum of square error (SSE) of 0.742 and 0.996, respectively.

Keywords: anion exchange resin, Eley-Rideal, Langmuir-Hinshelwood-Hougen-Watson, transesterification

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1443 Entropy Risk Factor Model of Exchange Rate Prediction

Authors: Darrol Stanley, Levan Efremidze, Jannie Rossouw

Abstract:

We investigate the predictability of the USD/ZAR (South African Rand) exchange rate with sample entropy analytics for the period of 2004-2015. We calculate sample entropy based on the daily data of the exchange rate and conduct empirical implementation of several market timing rules based on these entropy signals. The dynamic investment portfolio based on entropy signals produces better risk adjusted performance than a buy and hold strategy. The returns are estimated on the portfolio values in U.S. dollars. These results are preliminary and do not yet account for reasonable transactions costs, although these are very small in currency markets.

Keywords: currency trading, entropy, market timing, risk factor model

Procedia PDF Downloads 239
1442 The Effect of Deficit Financing on Macro-Economic Variables in Nigeria (1970-2013)

Authors: Ezeoke Callistus Obiora, Ezeoke Nneka Angela

Abstract:

The study investigated the effect of deficit financing on macroeconomic variables in Nigeria. The specific objectives included to find out the relationship between deficit financing and GDP, interest rate, inflation rate, money supply, exchange rate and private investment respectively on a time series covering a period of 44 years (1970 – 2013). The Ordinary Least Square multiple regression produced statistics for the coefficient of determination (R2), F-test, t-test used for the interpretation of the study. The findings revealed that Deficit financing has significant positive effect on GDP and exchange rate. Again, deficit financing has a positive and insignificant relationship inflation, money supply and investment. Only interest rate recorded negative yet insignificant relationship with deficit financing. The implications of the findings are that deficit financing can be a veritable tool for boosting economic development in Nigeria, but the influential positively rising exchange rate implies that deficit financing devalues the Naira exchange rate to other currencies indicating that deficit financing can affect Nigerians competitive advantage at the world market. Thus, the study concludes that deficit financing has not encouraged economic growth in Nigeria.

Keywords: deficit financing, money supply, exchange rate, inflation, GDP, investment, Nigeria

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1441 Separation of CO2 Using MFI-Alumina Nanocomposite Hollow Fiber Ion-Exchanged with Alkali Metal Cation

Authors: A. Alshebani, Y. Swesi, S. Mrayed, F. Altaher, I. Musbah

Abstract:

Cs-type nanocomposite zeolite membrane was successfully synthesized on an alumina ceramic hollow fibre with a mean outer diameter of 1.7 mm; cesium cationic exchange test was carried out inside test module with mean wall thickness of 230 μm and an average crossing pore size smaller than 0.2 μm. Separation factor of n-butane/H2 obtained indicate that a relatively high quality closed to 20. Maxwell-Stefan modeling provides an equivalent thickness lower than 1 µm. To compare the difference an application to CO2/N2 separation has been achieved, reaching separation factors close to (4,18) before and after cation exchange on H-zeolite membrane formed within the pores of a ceramic alumina substrate.

Keywords: MFI membrane, nanocomposite, ceramic hollow fibre, CO2, ion-exchange

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1440 Gains and Pitfalls of Participating on International Staff Exchange Programs: Individual Experiences of Academic Staff of Makerere University, Uganda

Authors: David Onen

Abstract:

Staff exchanges amongst different work organizations are a growing international phenomenon. In higher education in particular, it is not only the staff participating on international exchange programs, but their students as well. The practice of exchanging staff is premised on the belief that participating members of staff would not only get the chance to network with colleagues from partner institutions but also gain the opportunity for knowledge sharing and skills development. As a result, it would not only benefit the participating individual staff but their institutions too. However, in practice, staff exchange programs everywhere are not all ‘a bed of roses’. In fact, some of the programs seem to be laden with unapparent source of trouble or danger for the participating staff. This paper is a report on an on-going study investigating the experiences of members of academic staff of Makerere University in Uganda who have ever participated on international staff exchange programs. The study is aimed at documenting individual experiences in order to stimulate, not only a debate, but practical ways of enriching the experiences of staff who engage on well-meant international staff exchange programs. The study has employed an exploratory survey research design in which self-administered questionnaire and interview guide are being used to collect data from university academic staff respondents selected through snow-ball and purposive sampling techniques. Data have been analysed with the use of appropriate descriptive and inferential statistics as well as content analysis techniques. Preliminary study findings reveal that the majority of the respondents (95.5%) were, to a large extent, fully satisfied with their participation on the staff exchange programs. Many attested to gaining new experience (97%), networking (75%), gaining new knowledge (94%), acquiring new skills (88%), and therefore bringing to their institutions something ‘new’ and ‘beneficial’. However, a reasonably large percentage (57%) of the participants too expressed dissatisfaction in the institutional support that Makerere University gave them during their participation on the exchange programs. Some respondents reported about the ‘unfriendly welcome’ they received upon returning ‘home’ because colleagues detested how they were chosen to participate on such programs. The researcher thus concluded that international staff exchange programs are truly beneficial to both the participating staff and their institutions though with pitfalls. The researcher thus recommended for mutual and preferably equal engagement of the participating institutions on staff exchange programs if such programs are to benefit both the participating staff and institutions. Besides, exchange programs require clear terms of cooperation including on how staff are selected, facilitated and what are expected of the sending and host institutions as well as the concerned staff.

Keywords: gains, exchange programs, higher education, pitfalls

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1439 Separation of CO2 Using MFI-Alumina Nanocomposite Hollow Fibre Ion-Exchanged with Alkali Metal Cation

Authors: A. Alshebani, Y. Swesi, S. Mrayed, F. Altaher, I. Musbah

Abstract:

Cs-type nanocomposite zeolite membrane was successfully synthesized on a alumina ceramic hollow fibre with a mean outer diameter of 1.7 mm, cesium cationic exchange test was carried out inside test module with mean wall thickness of 230 μm and an average crossing pore size smaller than 0.2 μm. Separation factor of n-butane/H2 obtained indicate that a relatively high quality closed to 20. Maxwell-Stefan modeling provides an equivalent thickness lower than 1 µm. To compare the difference an application to CO2/N2 separation has been achieved, reaching separation factors close to (4,18) before and after cation exchange on H-zeolite membrane formed within the pores of a ceramic alumina substrate.

Keywords: MFI membrane, CO2, nanocomposite, ceramic hollow fibre, ion-exchange

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1438 Short-Term Energy Efficiency Decay and Risk Analysis of Ground Source Heat Pump System

Authors: Tu Shuyang, Zhang Xu, Zhou Xiang

Abstract:

The objective of this paper is to investigate the effect of short-term heat exchange decay of ground heat exchanger (GHE) on the ground source heat pump (GSHP) energy efficiency and capacity. A resistance-capacitance (RC) model was developed and adopted to simulate the transient characteristics of the ground thermal condition and heat exchange. The capacity change of the GSHP was linked to the inlet and outlet water temperature by polynomial fitting according to measured parameters given by heat pump manufacturers. Thus, the model, which combined the heat exchange decay with the capacity change, reflected the energy efficiency decay of the whole system. A case of GSHP system was analyzed by the model, and the result showed that there was risk that the GSHP might not meet the load demand because of the efficiency decay in a short-term operation. The conclusion would provide some guidances for GSHP system design to overcome the risk.

Keywords: capacity, energy efficiency, GSHP, heat exchange

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1437 Dynamic Comovements between Exchange Rates, Stock Prices and Oil Prices: Evidence from Developed and Emerging Latin American Markets

Authors: Nini Johana Marin Rodriguez

Abstract:

This paper applies DCC, EWMA and OGARCH models to compare the dynamic correlations between exchange rates, oil prices, exchange rates and stock markets to examine the time-varying conditional correlations to the daily oil prices and index returns in relation to the US dollar/local currency for developed (Canada and Mexico) and emerging Latin American markets (Brazil, Chile, Colombia and Peru). Changes in correlation interactions are indicative of structural changes in market linkages with implications to contagion and interdependence. For each pair of stock price-exchange rate and oil price-US dollar/local currency, empirical evidence confirms of a strengthening negative correlation in the last decade. Methodologies suggest only two events have significatively impact in the countries analyzed: global financial crisis and Europe crisis, both events are associated with shifts of correlations to stronger negative level for most of the pairs analyzed. While, the first event has a shifting effect on mainly emerging members, the latter affects developed members. The identification of these relationships provides benefits in risk diversification and inflation targeting.

Keywords: crude oil, dynamic conditional correlation, exchange rates, interdependence, stock prices

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1436 Modeling the Philippine Stock Exchange Index Closing Value Using Artificial Neural Network

Authors: Frankie Burgos, Emely Munar, Conrado Basa

Abstract:

This paper aimed at developing an artificial neural network (ANN) model specifically for the Philippine Stock Exchange index closing value. The inputs to the ANN are US Dollar and Philippine Peso(USD-PHP) exchange rate, GDP growth of the country, quarterly inflation rate, 10-year bond yield, credit rating of the country, previous open, high, low, close values and volume of trade of the Philippine Stock Exchange Index (PSEi), gold price of the previous day, National Association of Securities Dealers Automated Quotations (NASDAQ), Standard and Poor’s 500 (S & P 500) and the iShares MSCI Philippines ETF (EPHE) previous closing value. The target is composed of the closing value of the PSEi during the 627 trading days from November 3, 2011, to May 30, 2014. MATLAB’s Neural Network toolbox was employed to create, train and simulate the network using multi-layer feed forward neural network with back-propagation algorithm. The results satisfactorily show that the neural network developed has the ability to model the PSEi, which is affected by both internal and external economic factors. It was found out that the inputs used are the main factors that influence the movement of the PSEi closing value.

Keywords: artificial neural networks, artificial intelligence, philippine stocks exchange index, stocks trading

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1435 Effect of the Binary and Ternary Exchanges on Crystallinity and Textural Properties of X Zeolites

Authors: H. Hammoudi, S. Bendenia, K. Marouf-Khelifa, R. Marouf, J. Schott, A. Khelifa

Abstract:

The ionic exchange of the NaX zeolite by Cu2+ and/or Zn2+ cations is progressively driven while following the development of some of its characteristic: crystallinity by XR diffraction, profile of isotherms, RI criterion, isosteric adsorption heat and microporous volume using both the Dubinin–Radushkevich (DR) equation and the t-plot through the Lippens–de Boer method which also makes it possible to determine the external surface area. Results show that the cationic exchange process, in the case of Cu2+ introduced at higher degree, is accompanied by crystalline degradation for Cu(x)X, in contrast to Zn2+-exchanged zeolite X. This degradation occurs without significant presence of mesopores, because the RI criterion values were found to be much lower than 2.2. A comparison between the binary and ternary exchanges shows that the curves of CuZn(x)X are clearly below those of Zn(x)X and Cu(x)X, whatever the examined parameter. On the other hand, the curves relating to CuZn(x)X tend towards those of Cu(x)X. This would again confirm the sensitivity of the crystalline structure of CuZn(x)X with respect to the introduction of Cu2+ cations. An original result is the distortion of the zeolitic framework of X zeolites at middle exchange degree, when Cu2+ competes with another divalent cation, such as Zn2+, for the occupancy of sites distributed within zeolitic cavities. In other words, the ternary exchange accentuates the crystalline degradation of X zeolites. An unexpected result also is the no correlation between crystal damage and the external surface area.

Keywords: adsorption, crystallinity, ion exchange, zeolite

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1434 Hybrid Model for Measuring the Hedge Strategy in Exchange Risk in Information Technology Industry

Authors: Yi-Hsien Wang, Fu-Ju Yang, Hwa-Rong Shen, Rui-Lin Tseng

Abstract:

The business is notably related to the market risk according to the increase of liberalization of financial markets. Hence, the company usually utilized high financial leverage of derivatives to hedge the risk. When the company choose different hedging instruments to face a variety of exchange rate risk, we employ the Multinomial Logistic-AHP to analyze the impact of various derivatives. Hence, the research summarized the literature on relevant factors affecting managers selected exchange rate hedging instruments, using Multinomial Logistic Model and and further integrate AHP. Using Experts’ Questionnaires can test multi-level selection and hedging effect of different hedging instruments in order to calculate the hedging instruments and the multi-level factors of weights to understand the gap between the empirical results and practical operation. Finally, the Multinomial Logistic-AHP Model will sort the weights to analyze. The research findings can be a basis reference for investors in decision-making.

Keywords: exchange rate risk, derivatives, hedge, multinomial logistic-AHP

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1433 An Empirical Investigation into the Effect of Macroeconomic Policy on Economic Growth in Nigeria

Authors: Rakiya Abba

Abstract:

This paper investigates the effect of the money supply, exchange and interest rate on economic growth in Nigeria through the application of Augmented Dickey-Fuller technique in testing the unit root property of the series and Granger causality test of causation between GDP, money supply, the exchange, and interest rate. The results of unit root suggest that all the variables in the model are stationary at 1, 5 and 10 percent level of significance, and the results of Causality suggest that money supply and exchange granger cause IR, the result further reveals two – way causation existed between M2 and EXR while IR granger cause GDP the null hypothesis is rejected and GDP does not granger cause IR as indicated by their probability values of 0.4805 and confirmed by F-statistics values of 0.75483. The results revealed that M2 and EXR do not granger causes GDP, the null hypothesis is accepted at 75percent 18percent respectively as indicated by their probability values of 0.7472 and 0.1830 respectively; also, GDP does not granger cause M2 and EXR. The Johansen cointegration result indicates that despite GDP does not granger cause M2, IR, and EXR, but there existed 1 cointegrating equation, implying the existence of long-run relationship between GDP, M2 IR, and EXR. A major policy implication of this result is that economic growth is function of and money supply and exchange rate, effective monetary policies should direct on manipulating instruments and importance should be placed on justification for adopting a particular policy be rationalized in order to increase growth in economy

Keywords: economic growth, money supply, interest rate, exchange rate, causality

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1432 Arsenic Removal by Membrane Technology, Adsorption and Ion Exchange: An Environmental Lifecycle Assessment

Authors: Karan R. Chavan, Paula Saavalainen, Kumudini V. Marathe, Riitta L. Keiski, Ganapati D. Yadav

Abstract:

Co-contamination of groundwaters by arsenic in different forms is often observed around the globe. Arsenic is introduced into the waters by several mechanisms and different technologies are proposed and practiced for effective removal. The assessment of three prominent technologies, namely, adsorption, ion exchange and nanofiltration was carried out in this study based on lifecycle methodology. The life of the technologies was divided into two stages: cradle to gate (C-G) and gate to gate (G-G), in order to find out the impacts in different categories of environmental burdens, human health and resource consumption. Life cycle inventory was estimated by use of models and design equations concerning with the different technologies. Regeneration was considered for each technology and over the course of its full lifetime. The impact values of adsorption technology for the C-G stage are greater by thousand times (103) and million times (106) compared to ion exchange and nanofiltration technologies, respectively. The impact of G-G stage of the lifecycle is the major contributor of the impact for all the 3 technologies due to electricity consumption during the operation. Overall, the ion Exchange technology fares well in this study of removal of As (V) only.

Keywords: arsenic, nanofiltration, lifecycle assessment, membrane technology

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1431 Behavior of Iran Stock Exchange and Impacts of US Oil and Financial Markets

Authors: Erfan Memarian, Seyyed Fazayel Alizadeh

Abstract:

This study aims to evaluate the impacts of the oil and financial markets of the United States on Iran stock exchange and to develop an ARDL model to predict the short and long-term relationship between these markets. In this regard, all 713 weekly data between 28 July 1999 and 20 March 2013 were analyzed by using Microfit4.0 and Eviews7 econometric softwares. The independent variable of the study is the “Price and Yield Index (TEDPIX)” of Tehran Stock Exchange and the independent variables include S & P 500 Index, the US three-month treasury bill rate and West Texas Intermediate oil spot price index. The results show that the West Texas Intermediate oil spot price and the S&P 500 indices have significant positive relationships with Iran's TEDPIX. Also, there exists a significant negative relationship between Iran's TEDPIX and the US three-month Treasury bill rate.

Keywords: TEDPIX; Tehran Stock Exchange; S&P 500 index; USA three-month Treasury bill rate; West Texas Intermediate oil

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1430 The Effect of Tax Avoidance on Firm Value: Evidence from Amman Stock Exchange

Authors: Mohammad Abu Nassar, Mahmoud Al Khalilah, Hussein Abu Nassar

Abstract:

The purpose of this study is to examine whether corporate tax avoidance practices can impact firm value in the Jordanian context. The study employs a quantitative approach using s sample of (124) industrial and services companies listed on the Amman Stock Exchange for the period from 2010 to 2019. Multiple linear regression analysis has been applied to test the study's hypothesis. The study employs effective tax rate and book-tax difference to measure tax avoidance and Tobin's Q factor to measure firm value. The results of the study revealed that tax avoidance practices, when measured using effective tax rates, do not significantly impact firm value. When the book-tax difference is used to measure tax avoidance, the study results showed a negative impact on firm value. The result of the study has not supported the traditional view of tax avoidance as a transfer of wealth from the government to shareholders for industrial and services companies listed on the Amman Stock Exchange, indicating that Jordanian firms should not use tax avoidance strategies to enhance their value.

Keywords: tax avoidance, effective tax rate, book-tax difference, firm value, Amman stock exchange

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1429 Synthesis of Epoxidized Castor Oil Using a Sulphonated Polystyrene Type Cation Exchange Resin and Its Blend Preparation with Epoxy Resin

Authors: G. S. Sudha, Smita Mohanty, S. K. Nayak

Abstract:

Epoxidized oils can replace petroleum derived materials in numerous industrial applications, because of their respectable oxirane oxygen content and high reactivity of oxirane ring. Epoxidized castor oil (ECO) has synthesized in the presence of a sulphonated polystyrene type cation exchange resin. The formation of the oxirane ring was confirmed by Fourier Transform Infrared Spectroscopy (FTIR) analysis. The epoxidation reaction was evaluated by Nuclear Magnetic Resonance (NMR) studies. ECO is used as a toughening phase to increase the toughness of petroleum-based epoxy resin.

Keywords: epoxy resin, epoxidized castor oil, sulphonated polystyrene type cation exchange resin, petroleum derived materials

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1428 Determinants of Financial Performance of South African Businesses in Africa: Evidence from JSE Listed Telecommunications Companies

Authors: Nomakhosi Tshuma, Carley Chetty

Abstract:

This study employed panel regression analysis to investigate the financial performance determinants of MTN and Vodacom’s rest of Africa businesses between 2012 to 2020. It used net profit margin, return on assets (ROA), and return on equity (ROE) as financial performance proxies. Financial performance determinants investigated were asset size, debt ratio, liquidity, number of subscribers, and exchange rate. Data relating to exchange rates were obtained from the World Bank website, while financial data and subscriber information were obtained from the companies’ audited financial statements. The study found statistically significant negative relationships between debt and both ROA and net profit, exchange rate and both ROA and net profit, and subscribers and ROE. It also found significant positive relationships between ROE and both asset size and exchange rate. The study recommends strategic options that optimise on the above findings, and these include infrastructure sharing to reduce infrastructure costs and the minimisation of foreign-denominated debt.

Keywords: financial performance, determinants of financial performance, business in Africa, telecommunications industry

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1427 Studies on Separation of Scandium from Sulfate Environment Using Ion Exchange Technique

Authors: H. Hajmohammadi , A. H. Jafari, M. Eskandari Nasab

Abstract:

The ion exchange method was used to assess the absorption of sulfate media from laboratory-grade materials. The Taguchi method was employed for determining the optimum conditions for scandium adsorption. Results show that optimum conditions for scandium adsorption from sulfate were obtained by Purolite C100 cationic resin in 0.1 g/l sulfuric acid and scandium concentration of 2 g/l at 25 °C. Studies also showed that lowering H₂SO₄ concentration and aqueous phase temperature leads to an increase in Sc adsorption. Visual Minteq software was used to ascertain the various possible cation types and the effect of concentration of scandium ion species on scandium adsorption by cationic resins. The simulation results of the above software show that scandium ion species are often cationic species that are consistent with experimental data.

Keywords: scandium, ion exchange resin, simulation, leach copper

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1426 Language and Culture Exchange: Tandem Language Learning for University Students

Authors: Hebe Wong, Luz Fernandez Calventos

Abstract:

Tandem language learning, a language exchange process based on the principles of autonomy and reciprocity, provides opportunities for interlocutors to learn each other’s language by communicating online or face-to-face. While much attention has been paid to the process and outcomes of tandem learning via email, little has been discussed about the effectiveness of face-to-face tandem learning on language and culture exchange for university students. The LACTS (Language and Culture Tandem Scheme), an 8-week project, was set up to study students’ perceptions of conducting tandem learning to assist their language and culture exchange. Students of both post-graduate and undergraduate programmes (N=103) from a Hong Kong SAR university were put in groups of 4 to 6 according to their availability and language preferences and met for an hour a week. While sample task sheets on a range of topics were provided to assist the language exchange, all groups were encouraged to take charge of their meeting format and choose their own topics. At the end of the project, a 19-item questionnaire, which included both open-and closed-ended questions investigating students’ perceptions of reciprocal teaching and cultural exchange, was administered. Thirty-minute individual interviews were conducted to elicit students’ views and experiences in the LACTS activities. Quantitative and qualitative data analysis showed that most students agreed that the project had enhanced their cultural awareness and helped create an inclusive and participatory learning environment. Significant differences were found in students’ confidence in speaking their targeted language after joining the scheme. The interviews also provided rich data on the variety of formats and leadership patterns in student-led meetings, which could shed light on student autonomy and future tandem language learning projects.

Keywords: autonomy, reciprocity, tandem language learning, university students

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1425 Hydrometallurgical Recovery of Cobalt, Nickel, Lithium, and Manganese from Spent Lithium-Ion Batteries

Authors: E. K. Hardwick, L. B. Siwela, J. G. Falconer, M. E. Mathibela, W. Rolfe

Abstract:

Lithium-ion battery (LiB) demand has increased with the advancement in technologies. The applications include electric vehicles, cell phones, laptops, and many more devices. Typical components of the cathodes include lithium, cobalt, nickel, and manganese. Recycling the spent LiBs is necessary to reduce the ecological footprint of their production and use and to have a secondary source of valuable metals. A hydrometallurgical method was investigated for the recovery of cobalt and nickel from LiB cathodes. The cathodes were leached using a chloride solution. Ion exchange was then used to recover the chloro-complexes of the metals. The aim of the research was to determine the efficiency of a chloride leach, as well as ion exchange operating capacities that can be achieved for LiB recycling, and to establish the optimal operating conditions (ideal pH, temperature, leachate and eluant, flowrate, and reagent concentrations) for the recovery of the cathode metals. It was found that the leaching of the cathodes could be hindered by the formation of refractory metal oxides of cathode components. A reducing agent was necessary to improve the leaching rate and efficiency. Leaching was achieved using various chloride-containing solutions. The chloro-complexes were absorbed by the ion exchange resin and eluted to produce concentrated cobalt, nickel, lithium, and manganese streams. Chromatographic separation of these elements was achieved. Further work is currently underway to determine the optimal operating conditions for the recovery by ion exchange.

Keywords: cobalt, ion exchange, leachate formation, lithium-ion batteries, manganese, nickel

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1424 Quaternized PPO/PSF Anion Exchange Membranes Doped with ZnO-Nanoparticles for Fuel Cell Application

Authors: P. F. Msomi, P. T. Nonjola, P. G. Ndungu, J. Ramontja

Abstract:

In view of the projected global energy demand and increasing levels of greenhouse gases and pollutants issues have inspired an intense search for alternative new energy technologies, which will provide clean, low cost and environmentally friendly solutions to meet the end user requirements. Alkaline anion exchange membrane fuel cells (AAEMFC) have been recognized as ideal candidates for the generation of such clean energy for future stationary and mobile applications due to their many advantages. The key component of the AAEMFC is the anion exchange membrane (AEM). In this report, a series of quaternized poly (2.6 dimethyl – 1.4 phenylene oxide)/ polysulfone (QPPO/PSF) blend anionic exchange membranes (AEM) were successfully fabricated and characterized for alkaline fuel cell application. Zinc Oxide (ZnO) nanoparticles were introduced in the polymer matrix to enhance the intrinsic properties of the AEM. The characteristic properties of the QPPO/PSF and QPPO/PSF-ZnO blend membrane were investigated with X-ray diffraction (XRD), thermogravimetric analysis (TGA) scanning electron microscope (SEM) and contact angle (CA). To confirm successful quaternisation, FT-IR spectroscopy and proton nuclear magnetic resonance (1H NMR) were used. Other properties such as ion exchange capacity (IEC), water uptake, contact angle and ion conductivity (IC) were also undertaken to check if the prepared nanocomposite materials are suitable for fuel cell application. The membrane intrinsic properties were found to be enhanced by the addition of ZnO nanoparticles. The addition of ZnO nanoparticles resulted to a highest IEC of 3.72 mmol/g and a 30-fold IC increase of the nanocomposite due to its lower methanol permeability. The above results indicate that QPPO/PSF-ZnO is a good candidate for AAEMFC application.

Keywords: anion exchange membrane, fuel cell, zinc oxide nanoparticle, nanocomposite

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1423 Corporate Fund Mobilization for Listed Companies and Economic Development: Case of Mongolian Stock Exchange

Authors: Ernest Nweke, Enkhtuya Bavuudorj

Abstract:

The Mongolia Stock Exchange (MSE) serves as a vehicle for executing the privatization policy of Mongolian Government as it transitioned from socialist to free market economy. It was also the intention of the Government to develop the investment and securities market through its establishment and to further boost the ailing Mongolian economy. This paper focuses on the contributions of the Mongolian Stock Exchange (MSE) to the industrial and economic development of Mongolia via Corporate fund mobilization for listed companies in Mongolia. A study of this nature is imperative as economic development in Mongolia has been accelerated by corporate investments. The key purpose of the research was to critically analyze the operations of the MSE to ascertain the extent to which the objectives for which it was established have been accomplished and to assess its contributions to industrial and economic development of Mongolia. In achieving this, secondary data on the activities of the MSE; its market capitalization over the years were collected and analyzed vis-à-vis the figures for Mongolia’s macro-economic data for the same time period to determine whether the progressive increase in market capitalization of the MSE has positively impacted on Mongolia’s economic growth. Regression analysis package was utilized in dissecting the data. It was proven that the Mongolian Stock Exchange has contributed positively and significantly to Mongolia’s economic development though not yet to the desired level. Against the findings of this research, recommendations were made to address, the problems facing the MSE and to enhance its performance and ultimately its contributions to industrial and economic development of the Mongolian nation.

Keywords: Corporate Fund Mobilization, Gross Domestic Product (GDP), market capitalization, purchasing power, stock exchange

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1422 Ownership Structure and Portfolio Performance: Pre- and Post-Crisis Evidence from the Amman Stock Exchange

Authors: Mohammad Q. M. Momani

Abstract:

The objective of this study is to examine whether the value relevance of ownership structure changed as the Amman Stock Exchange market conditions changed. Using data from 2005 to 2014, the study finds that the performance of portfolios that contain firms with concentrated ownership structure declines significantly during the post-crisis period. These portfolios exhibit poor performance relative to portfolios that contain firms with dispersed ownership structure during the post-crisis period. The results argue that uninspired performance of the Amman Stock Exchange during the post-crisis period, increased the incentives for controlling shareholders to expropriate. Investors recognized these incentives and discounted firms that were more likely to expropriate.

Keywords: value relevance, ownership structure, portfolio performance, Jordan, ASE

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1421 Removal of Aggregates of Monoclonal Antibodies by Ion Exchange Chrmoatography

Authors: Ishan Arora, Anurag Rathore

Abstract:

The primary objective of this work was to study the effect of resin chemistry, pH and molarity of binding and elution buffer on aggregate removal using Cation Exchange Chromatography and find the optimum conditions which can give efficient aggregate removal with minimum loss of yield. Four different resins were used for carrying out the experiments: Fractogel EMD SO3-(S), Fractogel EMD COO-(M), Capto SP ImpRes and S Ceramic HyperD. Runs were carried out on the AKTA Avant system. Design of Experiments (DOE) was used for analysis using the JMP software. The dependence of the yield obtained using different resins on the operating conditions was studied. Success has been achieved in obtaining yield greater than 90% using Capto SP ImpRes and Fractogel EMD COO-(M) resins. It has also been found that a change in the operating conditions generally has different effects on the yields obtained using different resins.

Keywords: aggregates, cation exchange chromatography, design of experiments, monoclonal antibodies

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