Search results for: crystal growth

Authors: Tae Kyu An

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We demonstrate repurposing linear micropatterns on the CD as a master mold to fabricate TIPS-PEN microwires. From the micropatterns on CDs, we replicated polyurethane acrylate (PUA) templates which are robust and flexible until submicrometer scale patterns. Subsequently, 1.5 μm TIPS-PEN microwires separated by 1.5 μm were grown. Using crystal analysis tools with polarized optical microscopy and X-ray diffraction measurement, it was revealed that each TIPS-PEN microwires are highly crystalline and uniform compared to spin-coated films. It is attributed to the template-guided growth of TIPS-PEN crystals along the linear template, thus the OFETs comprised of TIPS-PEN microwires displayed the high field-effect mobility.

Keywords: compact disk, macro patterning, OFET, soft lithography

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Authors: Bernur Acikgoz

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The purpose of this paper is to investigate the effects of public spending on economic growth and examine the sources of economic growth in developed countries since the 1990s. This paper analyses whether public spending effect on economic growth based on Cobb-Douglas Production Function with the two econometric models with Autoregressive Distributed Lag (ARDL) and Dynamic Fixed Effect (DFE) for 21 developed countries (high-income OECD countries), over the period 1990-2013. Our models results are parallel to each other and the models support that public spending has an important role for economic growth. This result is accurate with theories and previous empirical studies.

Keywords: public spending, economic growth, panel data, ARDL models

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Authors: Umar Hayat, Shahid Ali, Lala Rukh

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Foreign aid is one of the critical variables that promote economic growth. This paper is an attempt to examine the long-run relationship between foreign aid and economic growth for Pakistan over the period of 1972 to 2021. This study uses Johnson's co-integration technique to investigate the long-run relationship among the variables in the model. For short-run dynamics, we utilized the Error Correction Mechanism (ECM). The results strongly support the conventional view about aid-led growth. The analysis of the impact of aid on growth both at the micro and the macro levels generally gives different results. The result shows that in the short run inference of foreign aid under the nondemocratic form of government is significant negatively, while foreign aid does not affect economic growth in the case of democratic government.

Keywords: foreign aid, economic growth, political regimes, developing economy

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Authors: Zohreh Derikvand

Abstract:

One new 2D metal-organic coordination polymer of Ni(II) namely [Ni2(ndc)2(DMSO)4(H2O)]n, where ndc = naphthalene-1,4-dicarboxylic acid and DMSO= dimethyl sulfoxide has been synthesized and characterized by elemental analysis, spectral (IR, UV-Vis), thermal (TG/DTG) analysis and single crystal X-ray diffraction. Compound 1 possesses a 2D layer structure constructed from dinuclear nickel(II) building blocks in which two crystallographically independent Ni2+ ions are bridged by ndc2– ligands and water molecule. The ndc2– ligands adopt μ3 bridging modes, linking the metal centers into a two-dimensional coordination framework. The two independent NiII cations are surrounded by dimethyl sulfoxide and naphthalene-1,4-dicarboxylate molecules in distorted octahedron geometry. In the crystal structures of 1 there are non-classical hydrogen bonding arrangements and C-H–π stacking interactions. Electrochemical behavior of [Ni2(ndc)2(DMSO)4(H2O)]n, (Ni-NDA) on the surface of carbon nanotube (CNTs) glassy carbon electrode (GCE) was described. The surface structure and composition of the sensor were characterized by scanning electron microscopy (SEM). Oxidation of fructose on the surface of modified electrode was investigated with cyclic voltammetry and electrochemical impedance spectroscopy (EIS) and the results showed that the Ni-NDA/CNTs film displays excellent electrochemical catalytic activities towards fructose oxidation.

Keywords: naphthalene-1, 4-dicarboxylic acid, crystal structure, coordination polymer, electrocatalysis, impedance spectroscopy

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Authors: Devi Eka Septiyani Arifin, Jrjeng Ruan

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As an approach to manipulate the performance of polymer thin film, epitaxy crystallization within polymer blends of poly(vinylidene fluoride) (PVDF) and its copolymer poly(vinylidene fluoride-trifluoroethylene) P(VDF-TrFE) was studied in this research, which involves the competition between phase separation and crystal growth of constitutive semicrystalline polymers. The unique piezoelectric feature of poly(vinylidene fluoride) crystalline phase is derived from the packing of molecular chains in all-trans conformation, which spatially arranges all the substituted fluorene atoms on one side of the molecular chain and hydrogen atoms on the other side. Therefore, the net dipole moment is induced across the lateral packing of molecular chains. Nevertheless, due to the mutual repulsion among fluorene atoms, this all-trans molecular conformation is not stable, and ready to change above curie temperature, where thermal energy is sufficient to cause segmental rotation. This research attempts to explore whether the epitaxial interactions between piezoelectric crystals and crystal lattice of hexamethylbenzene (HMB) crystalline platelet is able to stabilize this metastable all-trans molecular conformation or not. As an aromatic crystalline compound, the melt of HMB was surprisingly found able to dissolve the poly(vinylidene fluoride), resulting in homogeneous eutectic solution. Thus, after quenching this binary eutectic mixture to room temperature, subsequent heating or annealing processes were designed to explore the involve phase separation and crystallization behavior. The phase transition behaviors were observed in-situ by X-ray diffraction and differential scanning calorimetry (DSC). The molecular packing was observed via transmission electron microscope (TEM) and the principles of electron diffraction were brought to study the internal crystal structure epitaxially developed within thin films. Obtained results clearly indicated the occurrence of heteroepitaxy of PVDF/PVDF-TrFE on HMB crystalline platelet. Both the concentration of poly(vinylidene fluoride) and the mixing ratios of these two constitutive polymers have been adopted as the influential factors for studying the competition between the epitaxial crystallization of PVDF and P(VDF-TrFE) on HMB crystalline. Furthermore, the involved epitaxial relationship is to be deciphered and studied as a potential factor capable of guiding the wide spread of piezoelectric crystalline form.

Keywords: epitaxy, crystallization, crystalline platelet, thin film and mixing ratio

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Authors: Gisele Mah, Paul Saah

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The rising rates of inflation are hindering economic growth in developing nations. Hence, this study investigated the effects of inflation rates on the economic growth of South Africa using the secondary time series data from 1987 to 2022. The main objectives of this study were to investigate the long run relationship between inflation and economic growth, and also to determine the causality direction between these two variables. The study utilized the Autoregressive Distributed Lag (ARDL) bounds test of co-integration to investigate whether there is a long-run relationship between inflation and economic growth. The Pairwise Granger causality approach was employed to determine the second objective, which is the direction of causality. The study discovered only one co-integration relationship between our variables and it was between inflation and economic growth. The results showed that there is a negative and significant relationship between inflation and economic growth. There appeared to be a positive and significant relationship between economic growth and exchange rate. The interest rates have shown to be negative and insignificant in explaining economic growth. The study also established that inflation does Granger cause economic growth which is given as GDP. Similarly, the study discovered that inflation Granger causes exchange rates. Therefore, the study recommends that inflation should be decreased in South Africa, in order for economic growth to increase. Contrary, this study recommends that South Africa should increase its exchange rates, in order for economic growth to also increase.

Keywords: inflation rate, economic growth, South Africa, autoregressive distributed lag model

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Authors: N. R. Mohamad, H. Ono, H. Haroon, A. Salleh, N. M. Z. Hashim

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In this research, we have studied and analyzed the modulation of light and liquid crystal in HPDLCs using Finite Domain Time Difference (FDTD) method. HPDLCs are modeled as a mixture of polymer and liquid crystals (LCs) that categorized as an anisotropic medium. FDTD method is directly solves Maxwell’s equation with less approximation, so this method can analyze more flexible and general approach for the arbitrary anisotropic media. As the results from FDTD simulation, the highest diffraction efficiency occurred at ±19 degrees (Bragg angle) using p polarization incident beam to Bragg grating, Q > 10 when the pitch is 1µm. Therefore, the liquid crystal is assumed to be aligned parallel to the grating constant vector during these parameters.

Keywords: birefringence, diffraction efficiency, finite domain time difference, nematic liquid crystals

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Authors: Fekri Shawtari

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The banking sector plays a very crucial role in the economic development of the country. As a financial intermediary, it has assigned a great role in the economic growth and stability. This paper aims to examine the empirically the relationship between banking industry and economic growth in state of Qatar. We adopt the VAR vector error correction model (VECM) along with Granger causality to address the issue over the long-run and short-run between the banking sector and economic growth. It is expected that the results will give policy directions to the policymakers to make strategies that are conducive toward boosting development to achieve the targeted economic growth in current situation.

Keywords: economic growth, banking sector, Qatar, vector error correction model, VECM

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Authors: Philippe Gugler

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This contribution reflects some important questions regarding inter alia the economic development occurring in the light of the ASEAN’s goal of creating the ASEAN Economic Community (AEC) by 2015. We observe a continuing economic growth of GDP per capita over recent years despite the negative effects of the world economic crisis. IMF forecasts indicate that this trend will continue. The paper focuses on the analysis and comparison of economic growth trends of ASEAN countries.

Keywords: ASEAN, convergence, divergence, economic growth, globalization, integration

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Authors: Bindya Jacob

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The aim of the present study was to assess the quality of catchup growth induced by Oral Nutrition Supplement (ONS), in animal model of growth restriction due to under nutrition. Quality of catch-up growth was assessed by proportion of lean body mass (LBM) and fat mass (FM). Young SD rats were food restricted at 70% of normal caloric intake for 4 weeks; and re-fed at 120% of normal caloric intake for 4 weeks. Refeeding diet had 50% calories from animal diet and 50% from ONS formulated for optimal growth. After refeeding, the quantity and quality of catch-up growth were measured including weight, length, LBM and FM. During nutrient restriction, body weight and length of animals was reduced compared to healthy controls. Both LBM and FM were significantly lower than healthy controls (p < 0.001). Refeeding with ONS resulted in increase of weight and length, with significant catch-up growth compared to baseline (p < 0.001). Detailed examination of body composition showed that the catch-up in body weight was due to proportionate increase of LBM and FM, resulting in a final body composition similar to healthy controls. This data supports the use of well-designed ONS for recovery from growth restriction due to under nutrition, and return to normal growth trajectory characterized by normal ratio of lean and fat mass.

Keywords: catch up growth, body composition, nutrient restriction, healthy growth

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Authors: Christopher I. Ifeacho, Adeleke Omolade

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The paper examines the relationship between energy price dynamics and green growth in Sub Sahara African Countries. The quest for adopting green energy in order to improve green growth that can engender sustainability and stability has received more attention from researchers in recent times. This study uses a panel autoregressive distributed lag approach to investigate this relationship. Findings from the result showed that energy price dynamics and exchange rates have more short-run significant impacts on green growth in individual countries rather than the pooled result. Furthermore, the long-run result confirmed that inflation and capital have a significant long-run relationship with green growth. The causality test result revealed the existence of a bi-directional relationship between green growth and energy price dynamics. The study recommends caution in a currency devaluation and improvement in renewable energy production in the Sub Sahara Africa in order to achieve sustainable green growth.

Keywords: green growth, energy price dynamics, Sub Saharan Africa, relationship

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Authors: Jessica Ordoñez, Francisco Ochoa, Pascual García

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The objective of this paper is to analyze the relationship between return migration in Ecuador and economic growth. The improvement of macroeconomic conditions in Latin America, starting in 2012, makes the region a new migratory destination, in both senses in north-south and south-south flows. Current studies highlight only the role of the entrepreneurial migrant in generating employment and economic growth in the region. Nevertheless, it has not been considered that not all migrants are entrepreneurs and that not all entrepreneurs contribute to economic growth. This research compares the socioeconomic and labor characteristics of migrant returnees working as freelancers in Ecuador. The principal aim is to demystify the role of migrant entrepreneurs in regional growth and to identify socioeconomic characteristics that can enhance growth. A panel econometric model was used, which is part of the information from labor and macroeconomic surveys.

Keywords: economic growth, entrepreneur, migration, returned migration

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Authors: S. Boonlertnirun, R. Suvannasara, K. Boonlertnirun

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Hypoxia has negative effects on growth and crop yield, its severity is so varied depending on crop growth stages, duration of hypoxia and crop species. The objective was to evaluate the sensitive growth stage and the duration of hypoxia negatively affecting growth and yield of waxy corn. Pot experiment was conducted using a split plot in randomized complete block with 3 growth stages: V3 (3-4 true leaves), V7 (7-8 true leaves), and R1 (silking stage), and three hypoxic durations: 6, 9, and 12 days, in an open–ended outdoor greenhouse during January to March 2013. The results revealed that different growth stages had significantly (p < 0.5) different responses to hypoxia, seeing that the sensitive growth stage affecting plant height, yield and yield components was mostly detected in V7 growth stage whereas leaf greenness and days to silking were sensitive to hypoxia at R1 growth stage. Different hypoxic durations significantly affected the yield and yield components, hypoxic duration of twelve days showed the most negative effect greater than the others. In this present study, it can be concluded that waxy corn plants were waterlogged at V7 growth stage for twelve days had the most negative effect on yield and yield components.

Keywords: hypoxia duration, waxy corn, growth stage, Zea mays L.

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Authors: T. N. Tran Thi, J. Morse, C. Detlefs, P. K. Cook, C. Yıldırım, A. C. Jakobsen, T. Zhou, J. Hartwig, V. Zurbig, D. Caliste, B. Fernandez, D. Eon, O. Loto, M. L. Hicks, A. Pakpour-Tabrizi, J. Baruchel

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The ability to grow boron-doped diamond epilayers of high crystalline quality is a prerequisite for the fabrication of diamond power electronic devices, in particular high voltage diodes and metal-oxide-semiconductor (MOS) transistors. Boron and intrinsic diamond layers are homoepitaxially overgrown by microwave assisted chemical vapour deposition (MWCVD) on single crystal high pressure, high temperature (HPHT) grown bulk diamond substrates. Various epilayer thicknesses were grown, with dopant concentrations ranging from 1021 atom/cm³ at nanometer thickness in the case of 'delta doping', up 1016 atom/cm³ and 50µm thickness or high electric field drift regions. The crystalline quality of these overgrown layers as regards defects, strain, distortion… is critical for the device performance through its relation to the final electrical properties (Hall mobility, breakdown voltage...). In addition to the optimization of the epilayer growth conditions in the MWCVD reactor, other important questions related to the crystalline quality of the overgrown layer(s) are: 1) what is the dependence on the bulk quality and surface preparation methods of the HPHT diamond substrate? 2) how do defects already present in the substrate crystal propagate into the overgrown layer; 3) what types of new defects are created during overgrowth, what are their growth mechanisms, and how can these defects be avoided? 4) how can we relate in a quantitative manner parameters related to the measured crystalline quality of the boron doped layer to the electronic properties of final processed devices? We describe synchrotron-based techniques developed to address these questions. These techniques allow the visualization of local defects and crystal distortion which complements the data obtained by other well-established analysis methods such as AFM, SIMS, Hall conductivity…. We have used Grazing Incidence X-ray Diffraction (GIXRD) at the ID01 beamline of the ESRF to study lattice parameters and damage (strain, tilt and mosaic spread) both in diamond substrate near surface layers and in thick (10–50 µm) overgrown boron doped diamond epi-layers. Micro- and nano-section topography have been carried out at both the BM05 and ID06-ESRF) beamlines using rocking curve imaging techniques to study defects which have propagated from the substrate into the overgrown layer(s) and their influence on final electronic device performance. These studies were performed using various commercially sourced HPHT grown diamond substrates, with the MWCVD overgrowth carried out at the Fraunhofer IAF-Germany. The synchrotron results are in good agreement with low-temperature (5°K) cathodoluminescence spectroscopy carried out on the grown samples using an Inspect F5O FESEM fitted with an IHR spectrometer.

Keywords: synchrotron X-ray diffaction, crystalline quality, defects, diamond overgrowth, rocking curve imaging

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Authors: Sungsoo Na, Chanho Park

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Lung cancer is one of the most common severe diseases driving to the death of a human. Lung cancer can be divided into two cases of small-cell lung cancer (SCLC) and non-SCLC (NSCLC), and about 80% of lung cancers belong to the case of NSCLC. From several studies, the correlation between epidermal growth factor receptor (EGFR) and NSCLCs has been investigated. Therefore, EGFR inhibitor drugs such as gefitinib and erlotinib have been used as lung cancer treatments. However, the treatments result showed low response (10~20%) in clinical trials due to EGFR mutations that cause the drug resistance. Patients with resistance to EGFR inhibitor drugs usually are positive to KRAS mutation. Therefore, assessment of EGFR and KRAS mutation is essential for target therapies of NSCLC patient. In order to overcome the limitation of conventional therapies, overall EGFR and KRAS mutations have to be monitored. In this work, the only detection of EGFR will be presented. A variety of techniques has been presented for the detection of EGFR mutations. The standard detection method of EGFR mutation in ctDNA relies on real-time polymerase chain reaction (PCR). Real-time PCR method provides high sensitive detection performance. However, as the amplification step increases cost effect and complexity increase as well. Other types of technology such as BEAMing, next generation sequencing (NGS), an electrochemical sensor and silicon nanowire field-effect transistor have been presented. However, those technologies have limitations of low sensitivity, high cost and complexity of data analyzation. In this report, we propose a label-free and high-sensitive detection method of lung cancer using quartz crystal microbalance based platform. The proposed platform is able to sense lung cancer mutant DNA with a limit of detection of 1nM.

Keywords: cancer DNA, resonance frequency, quartz crystal microbalance, lung cancer

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Authors: Elsayeda M. Elgaml, Dina M. Ibrahim, Elsayed A. Sallam

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Association rule mining is one of the most important fields of data mining and knowledge discovery. In this paper, we propose an efficient multiple support frequent pattern growth algorithm which we called “MSFP-growth” that enhancing the FP-growth algorithm by making infrequent child node pruning step with multiple minimum support using maximum constrains. The algorithm is implemented, and it is compared with other common algorithms: Apriori-multiple minimum supports using maximum constraints and FP-growth. The experimental results show that the rule mining from the proposed algorithm are interesting and our algorithm achieved better performance than other algorithms without scarifying the accuracy.

Keywords: association rules, FP-growth, multiple minimum supports, Weka tool

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Authors: Christopher Ikechukwu Ifeacho

Abstract:

The paper examines the relationship between energy price dynamics and green growth in Sub Sahara African Countries. The quest for adopting green energy in order to improve the green growth that can engender sustainability, and stability has received more attention from researchers in recent times. This study uses a panel Autoregressive distributed lag approach to investigate this relationship. Findings from the result showed that energy price dynamics and exchange rate have more short-run significant impacts on green growth in individual countries rather than the pooled result. Furthermore, the long-run result confirmed that inflation and capital have a significant long-run relationship with green growth. The causality test result revealed the existence of a bi-directional relationship between green growth and energy price dynamics. The study recommends caution in a currency devaluation and improvement in renewable energy production in the Sub Sahara Africa in order to achieve sustainable green growth.

Keywords: green growth, energy price dynamics, Sub Sahara Africa., sustainability

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Authors: A. Benatiallah, A. Hadjadj, D. Benatiallah, F. Abaidi, A. Harrouz

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Photovoltaic system is established as a reliable and economical source of electricity in rural and Sahara areas, especially in developing countries where the population is dispersed, has low consumption of energy and the grid power is not extended to these areas due to viability and financial problems. The production of energy by the photovoltaic system is very fluctuates and depend of meteorological conditions. Wind is a very important and often neglected parameter in the behavior of the solar module. The electric performances of a solar module to the silicon are very appreciable to the blows; in the present work we have studies the behavior of multi-crystal solar module according to the density of dust, and the principals electric feature of the solar module. An evaluation permits to affirm that a solar module under the effect of sand will collect a lower flux to the normal conditions.

Keywords: photovoltaic, multi-crystal module, experimental, effect of dust, performances

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Authors: Balthazar Temu, Zhao Yan, Bogdan-Petrin Ratiu, Sang Soon Oh, Qiang Li

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Quantum confinement can be used to increase efficiency and control the emitted spectra in lasers and LEDs. In semiconductor nanowires, quantum confinement can be achieved in the axial direction by stacking multiple quantum disks or in the radial direction by forming a core-shell structure. In this work we demonstrate room temperature lasing in topological photonic crystal nanowire array lasers by using the InGaAs radial quantum well as the gain material. The nanowires with the GaAs/ InGaAs/ InGaP quantum well structure are arranged in a deformed honeycomb lattice, forming a photonic crystal surface emitting laser (PCSEL) . Under optical pumping we show that the PCSEL lase at the wavelength of 1001 nm (undeformed pattern) and 966 nm (stretched pattern), with the lasing threshold of 103 µJ〖/cm 〗^2. We compare the lasing wavelengths from devices with three different nanowire diameters for undeformed compressed and stretched devices, showing that the lasing wavelength increases as the nanowire diameter increases. The impact of deforming the honeycomb pattern is studied, where it was found out that the lasing wavelengths of undeformed devices are always larger than the corresponding stretched or compressed devices with the same nanowire diameter. Using photoluminescence results and numerical simulations on the field profile and the quality factors of the devices, we establish that the lasing of the device is from the radial quantum well structure.

Keywords: honeycomb PCSEL, nanowire laser, photonic crystal laser, quantum well laser

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Authors: Jeeban Amgain

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This paper investigates the impact of the size and composition of government expenditure and tax on GDP per capita growth in 36 Asian economies over the period of 1991-2012. The research employs the technique of panel regression; Fixed Effects and Generalized Method of Moments (GMM) as well as other statistical and descriptive approaches. The finding concludes that the size of government expenditure and tax revenue are generally low in this region. GDP per capita growth is strongly negative in response to Government expenditure, however, no significant relationship can be measured in case of size of taxation although it is positively correlated with economic growth. Panel regression of decomposed fiscal components also shows that the pattern of allocation of expenditure and taxation really matters on growth. Taxes on international trade and property have a significant positive impact on growth. In contrast, a major portion of expenditure, i.e. expenditure on general public services, health and education are found to have significant negative impact on growth, implying that government expenditures are not being productive in the Asian region for some reasons. Comparatively smaller and efficient government size would enhance the growth.

Keywords: government expenditure, tax, GDP per capita growth, composition

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Authors: Anna Drzewicz, Marzena Tykarska

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The chiral liquid crystal phases form the helicoidal structure, which is characterized by the helical pitch and the helical twist sense. In anticlinic smectic phase with antiferroelectric properties three types of helix temperature dependence have been obtained: increased helical pitch with temperature and right-handed helix, decreased helical pitch with temperature and left-handed helix and the inversion of both. The change of helical twist sense may be observed during the transition from one liquid crystal phase to another or within one phase for the same substance. According to Gray and McDonnell theory, the helical handedness depends on the absolute configuration of the assymetric carbon atom and its position related to the rigid core of the molecule. However, this theory does not explain the inversion of helical twist sense phenomenon. It is supposed, that it may be caused by the presence of different conformers with opposite handendess, which concentration may change with temperature. In this work, the inversion of helical twist sense in the chiral liquid crystals differing in the length of alkyl chain, in the substitution the benzene ring by fluorine atoms and in the type of helix handedness was tested by vibrational spectroscopy (infrared and raman spectroscopy) and by nuclear magnetic resonance spectroscopy. The results obtained from the vibrational spectroscopy confirm the presence of different conformers. Moreover, the analysis of nuclear magnetic resonance spectra is very useful to check, on which structural fragments the change of conformations are important for the change of helical twist sense.

Keywords: helical twist sense, liquid crystals, nuclear magnetic resonance spectroscopy, vibrational spectroscopy

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Authors: Tanimola Kazeem Abiodun

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In the paper, attempt was made to investigate the impact of international trade on economic growth at the disaggregate level both from the theoretical and economic angle. The study in its contribution examines this impact at the disaggregated level. To this end, a hypothesis was formulated to investigate the short ?run and long run impact of international trade on growth in the country. In the econometrics investigation that follow, international trade was disaggregated to export and imports and their short run and long run effect on growth was examined. Also, the aggregate international trade was also investigated to see the long run effects of its own growth. The results of the findings indicate that; both export and import impact significantly to growth in the short run. The long-run impact of export on growth was found to be positive, significant and stable both. Engle-Granger co integration test and error correlation mechanism were applied to these long run relationships. For the import, while the short run was found to be positive and significant on its impact on growth, the long run relationship was found to be negative but not significant. Therefore, it is thus recommended among others that the country should engage more on export promotion drives.

Keywords: international trade, disaggregated, import, export, econometrics, trade, economic growth, foreign trade, import, export

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Authors: M. C. Theong, F. L. Ang, G. J. Muga

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Growth of firms is influenced by environmental changes such as the global and national economy. On the other hand, it indicates the economic situation of a country. Therefore, it is imperative for firms to be sensitive to changes and to stay competitive and remain compatible with the environment. The Malaysian construction industry is prone to environmental changes due to its complexity. In order to survive in the construction industry, focus on the development of the firms themselves to achieve long term their long term goals is vital besides maximizing profits. The objective of this paper is to measure growth of the public listed construction companies in Malaysia and to investigate the development of the companies with highest, moderate and lowest growth. Growth is measured based on the companies' sales between year 2008 and 2012 collected via secondary data collection method. Findings show that the highest average growth created is 235.20 % while the lowest average growth is -22.75%. The construction companies remained active in the construction industry by implementing different sets of strategies and involving in several types of construction projects.

Keywords: growth, Malaysian construction industry, public listed companies, sales

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Authors: Shoroog Alraddadi

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In this study, the effect of gamma irradiation on the structural and transport properties of Bismuth Telluride (Bi₂Te₃) thin films was investigated. Bi₂Te₃ thin films with thicknesses varying from 100 nm to 500 nm were grown using thermal evaporation in vacuum 10⁻⁵ Torr. The films were irradiated by Gamma radiation with different doses (50, 200, and 500 kGy). The crystal structure of Bi₂Te₃ thin films was studied by XRD diffraction. It was showed that the degree of crystallinity of films increases as the doses increase. Furthermore, it was found that the electrical conductivity of Bi₂Te₃ increase as the doses increase. From these results, it can be concluding that the effect of radiation on the structural and transport properties was positive at the levels of irradiation used.

Keywords: bismuth telluride, gamma irradiation, thin film, transport properties

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Authors: Abigail Mosetsanagape Mooketsi, Itumeleng Pleasure Mongale, Joel Hinaunye Eita

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The aim of this study is to analyse the impact of transport infrastructure on economic growth in South Africa through Engle Granger two step approach using the data from 1970 to 2013. GDP is used as a proxy for economic growth whilst rail transport (rail lines, rail goods transported) and air transport(air passengers carried, air freight) are used as proxies for transport infrastructure. The results showed that there is a positive long-run relationship between transport infrastructure and economic growth. The results show that South Africa’s economic growth can be boosted by providing transport infrastructure. The estimated models were simulated and the results that the model is a good fit. The findings of this research will be beneficial to policy makers, academics and it will also enhance the ability of the investors to make informed decisions about investing in South Africa.

Keywords: transport, infrastructure, economic growth, South Africa

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Authors: Olumuyiwa Ayoola Kokapi, Olugbenga Solomon Bello

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Dyes are organic compounds with complex aromatic molecular structure that resulted in fast colour on a substance. Dye effluent found in wastewater generated from the dyeing industries is one of the greatest contributors to water pollution. Groundnut hull (GH) is an agricultural material that constitutes waste in the environment. Environmental contamination by hazardous organic chemicals is an urgent problem, which is partially solved through adsorption technologies. The choice of groundnut hull was promised on the understanding that some materials of agricultural origin have shown potentials to act as Adsorbate for hazardous organic chemicals. The aim of this research is to evaluate the potential of groundnut hull to adsorb Crystal violet dye through kinetic, isotherm and thermodynamic studies. The prepared groundnut hulls was characterized using Brunauer, Emmett and Teller (BET), Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). Operational parameters such as contact time, initial dye concentration, pH, and effect of temperature were studied. Equilibrium time for the adsorption process was attained in 80 minutes. Adsorption isotherms used to test the adsorption data were Langmuir and Freundlich isotherms model. Thermodynamic parameters such as ∆G°, ∆H°, and ∆S° of the adsorption processes were determined. The results showed that the uptake of dye by groundnut hulls occurred at a faster rate, corresponding to an increase in adsorption capacity at equilibrium time of 80 min from 0.78 to 4.45 mg/g and 0.77 to 4.45mg/g with an increase in the initial dye concentration from 10 to 50 mg/L for pH 3.0 and 8.0 respectively. High regression values obtained for pseudo-second-order kinetic model, sum of square error (SSE%) values along with strong agreement between experimental and calculated values of qe proved that pseudo second-order kinetic model fitted more than pseudo first-order kinetic model. The result of Langmuir and Freundlich model showed that the adsorption data fit the Langmuir model more than the Freundlich model. Thermodynamic study demonstrated the feasibility, spontaneous and endothermic nature of the adsorption process due to negative values of free energy change (∆G) at all temperatures and positive value of enthalpy change (∆H) respectively. The positive values of ∆S showed that there was increased disorderliness and randomness at the solid/solution interface of crystal violet dye and groundnut hulls. The present investigation showed that, groundnut hulls (GH) is a good low-cost alternative adsorbent for the removal of Crystal Violet (CV) dye from aqueous solution.

Keywords: adsorption, crystal violet dye, groundnut halls, kinetics

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Authors: Zahra Amirhosseini, Mahtab Nameni

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The aim of this study was to investigate the relationship between growth, beta, and Company's cash. We calculate cash as dependent variable and growth opportunity and beta as independent variables. This study was based on an analysis of panel data. Population of the study is the companies which listed in Tehran Stock exchange and a financial data of 215 companies during the period 2010 to 2015 have been selected as the sample through systematic sampling. The results of the first hypothesis showed there is a significant relationship between growth opportunities cash holdings. Also according to the analysis done in the second hypothesis, we determined that there is an inverse relation between company risk and cash holdings.

Keywords: growth, beta, liquidity, company

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Authors: Givi Kupatadze

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Backward economies are facing a challenge of achieving sustainable high economic growth rate. Dominant growth models represent a roadmap in framing economic development strategy. This paper examines a relevance of the dominant growth models for backward economies. Cobb-Douglas production function, the Harrod-Domar model of economic growth, the Solow growth model and general formula of gross domestic product are examined to undertake a comprehensive study of the dominant growth models. Deductive research method allows to uncover major weaknesses of the dominant growth models and to come up with practical implications for economic development strategy. The key finding of the paper shows, contrary to what used to be taught by textbooks of economics, that constant returns to scale property of the dominant growth models are a mere coincidence and its generalization over space and time can be regarded as one of the most unfortunate mistakes in the whole field of political economy. The major suggestion of the paper for backward economies is that understanding and considering taxonomy of economic activities based on increasing and diminishing returns to scale represent a cornerstone of successful economic development strategy.

Keywords: backward economies, constant returns to scale, dominant growth models, taxonomy of economic activities

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Authors: G. Çelik Gül, F. Kurtuluş

Abstract:

Rare earths containing complex metal oxides have drawn much attention due to physical, chemical and optical properties which make them feasible in so many areas such as non-linear optical materials and ion exchanger. We have researched a systematic study to obtain rare earth containing zirconium molybdate compound, characterization, investigation of crystal system and calculation of unit cell parameters.  After a successful synthesis of Nd₂Zr₃(MoO₄)₉ which is a member of rare earth metal containing complex oxides family, X-ray diffraction (XRD), High Score Plus/Rietveld refinement analysis, and Fourier Transform Infrared Spectroscopy (FTIR) were completed to determine the crystal structure. Morphological properties and elemental composition were determined by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis. Thermal properties were observed via Thermogravimetric-differential thermal analysis (TG/DTA).

Keywords: Nd₂Zr₃(MoO₄)₉, powder x-ray diffraction, solid state synthesis, zirconium molybdates

Procedia PDF Downloads 396

Authors: F. Husem, M. E. Turan, Y. Sun, H. Ahlatci, I. Tozlu

Abstract:

Residual stress and fatigue crack growth rates are important to determine mechanical behavior of rails. This study aims to make relationship between residual stress and fatigue crack growth values in rails. For this purpose, three R260 quality rails (0.6-0.8% C, 0.6-1.25 Mn) were chosen. Residual stress of samples was measured by cutting method that is related in railway standard. Then samples were machined for fatigue crack growth test and analyze was completed according to the ASTM E647 standard which gives information about parameters of rails for this test. Microstructure characterizations were examined by Light Optic Microscope (LOM). The results showed that residual stress change with fatigue crack growth rate. The sample has highest residual stress exhibits highest crack growth rate and pearlitic structure can be seen clearly for all samples by microstructure analyze.

Keywords: residual stress, fatigue crack growth, R260, SEM, ASTM E647

Procedia PDF Downloads 326