An Examination of the Causal Relationship Between Tourism and Economic Growth in Ghana from 1987 to 2018

The growth of every nation is its ability to improve every sector of the economy that provides better outcomes through revenue mobilization and investment. With the Ghana’s attention shifted to tourism, it is imperative to identify how tourism could trigger growth in the country. Thus, the study sought to examine the causal relationship between tourism and economic growth of Ghana and its related challenges. The study adopted a mixed method approach in the collection and analysis of data. Both secondary and primary data were used in the analysis of the study. In analyzing the quantitative study, data on tourism and GDP from 1987 to 2018 were used. The study adopted the Johansen Cointegration test and the instrumental variable estimation to identify the causal relationship among the variables. The outcome of the study from the Johansen and Co-integration test instrumental variable showed that there is a unidirectional causal relationship between tourism receipt and GDP growth both in the short run and the long run and a positive significant effect of tourism on economic growth of Ghana. The result showed that government has been the major contributor to the sector. Also, the most challenging issue curtailing the sector was found to be the issue of the COVID 19 pandemic. As such, the study recommended that ensuring public-private partnership could improve the sector to ensure growth in the economy. Further extensive research is required to understand the effects of tourism on host communities. Keywords: Tourism, Gross Domestic Product (GDP), Economic Growth, Ghana, Tourism industry, Climate Change. DOI: 10.7176/JESD/11-20-04 Publication date:October 31st 202

Photon-assisted Landau-Zener transitions in a periodically driven Rabi dimer coupled to a dissipative mode

We investigate multiple photon-assisted Landau-Zener (LZ) transitions in a hybrid circuit quantum electrodynamics device in which each of two interacting transmission-line resonators is coupled to a qubit, and the qubits are driven by periodic driving fields and also coupled to a common phonon mode. The quantum state of the entire composite system is modeled using the multi-$\rm D_2$ Ansatz in combination with the time-dependent Dirac-Frenkel variational principle. Applying a sinusoidal driving field to one of the qubits, this device is an ideal platform to study the photon-assisted LZ transitions by comparing the dynamics of the two qubits. A series of interfering photon-assisted LZ transitions take place if the photon frequency is much smaller than the driving amplitude. Once the two energy scales are comparable, independent LZ transitions arise and a transition pathway is revealed using an energy diagram. It is found that both adiabatic and nonadiabatic transitions are involved in the dynamics. Used to model environmental effects on the LZ transitions, the common phonon mode coupled to the qubits allows for more available states to facilitate the LZ transitions. An analytical formula is obtained to estimate the short-time phonon population and produces results in reasonable agreement with numerical calculations. Equipped with the knowledge of the photon-assisted LZ transitions in the system, we can precisely manipulate the qubit state and successfully generate the qubit dynamics with a square-wave pattern by applying driving fields to both qubits, opening up new venues to manipulate the states of qubits and photons in quantum information devices and quantum computer

Millimeter-scale exfoliation of hBN with tunable flake thickness

As a two-dimensional (2D) dielectric material, hexagonal boron nitride (hBN) is in high demand for applications in photonics, nonlinear optics, and nanoelectronics. Unfortunately, the high-throughput preparation of macroscopic-scale, high-quality hBN flakes with controlled thickness is an ongoing challenge, limiting device fabrication and technological integration. Here, we present a metal thin-film exfoliation method to prepare hBN flakes with millimeter-scale dimension, near-unity yields, and tunable flake thickness distribution from 1-7 layers, a substantial improvement over scotch tape exfoliation. The single crystallinity and high quality of the exfoliated hBN are demonstrated with optical microscopy, atomic force microscopy, Raman spectroscopy, and second harmonic generation. We further explore a possible mechanism for the effectiveness and selectivity based on thin-film residual stress measurements, density functional theory calculations, and transmission electron microscopy imaging of the deposited metal films. We find that the magnitude of the residual tensile stress induced by thin film deposition plays a key role in determining exfoliated flake thickness in a manner which closely resembles 3D semiconductor spalling. Lastly, we demonstrate that our exfoliated, large-area hBN flakes can be readily incorporated as encapsulating layers for other 2D monolayers. Altogether, this method brings us one step closer to the high throughput, mass production of hBN-based 2D photonic, optoelectronic, and quantum devices.Comment: 21 pages, 5 figures, work completed at Stanford Universit

The effect of polyacrylic Acid (PAA) binder molecular weight on the performance of alumina-coated polyolefin separator for lithium-ion batteries (LIBs)

LIBs have been widely used for electronics and electric vehicles (EVs). Apart from the electrochemically active electrodes, separator also plays an important role in the battery performance. Due to the low electrolyte uptake and low thermal stability of commercial polyolefin membrane separators, ceramic-coated separators have attracted tremendous attentions. However, the commonly used non-aqueous polymer binders have a low binding strength and cause environmental pollution. In this work, aqueous PAA was used as the binder for alumina coating. By comparing two PAA binders with contrasting molecular weights (MW), we observed a better thermal stability and ion redistribution capability in the coated separator with high MW PAA binder. We concluded this work by proposing possible solutions to improve the structural integrity of the coating.Bachelor of Engineering (Materials Engineering

Dynamic nonlinear CO2 emission effects of urbanization routes in the eight most populous countries.

A dynamic STIRPAT model used in the current study is based on panel data from the eight most populous countries from 1975 to 2020, revealing the nonlinear effects of urbanization routes (percentage of total urbanization, percentage of small cities and percentage of large cities) on carbon dioxide (CO2) emissions. Using "Dynamic Display Unrelated Regression (DSUR)" and "Fully Modified Ordinary Least Squares (FMOLS)" regressions, the outcomes reflect that percentage of total urbanization and percentage of small cities have an incremental influence on carbon dioxide emissions. However, square percentage of small cities and square percentage of total urbanization have significant adverse effects on carbon dioxide (CO2) emissions. The positive relationship between the percentage of small cities, percentage of total urbanization and CO2 emissions and the negative relationship between the square percentage of small cities, square percentage of total urbanization and CO2 emissions legitimize the inverted U-shaped EKC hypothesis. The impact of the percentage of large cities on carbon dioxide emissions is significantly negative, while the impact of the square percentage of large cities on carbon dioxide emissions is significantly positive, validating a U-shaped EKC hypothesis. The incremental effect of percentage of small cities and percentage of total urbanization on long-term environmental degradation can provide support for ecological modernization theory. Energy intensity, Gross Domestic Product (GDP), industrial growth and transport infrastructure stimulate long-term CO2 emissions. Country-level findings from the AMG estimator support a U-shaped link between the percentage of small cities and CO2 emissions for each country in the entire panel except the United States. In addition, the Dumitrescu and Hulin causality tests yield a two-way causality between emission of carbon dioxide and squared percentage of total urbanization, between the percentage of the large cities and emission of carbon dioxide, and between energy intensity and emission of carbon dioxide. This study proposes renewable energy options and green city-friendly technologies to improve the environmental quality of urban areas

Estimation of the long run nonlinear environmental effect of urbanization pathways.

Estimation of the long run nonlinear environmental effect of urbanization pathways.</p

Panel variable data interpretation, quantification and sources.

Panel variable data interpretation, quantification and sources.</p

Findings of cross sectional correlation in panel variable data.

Findings of cross sectional correlation in panel variable data.</p

Statistical summary and correlation of panel variables.

Statistical summary and correlation of panel variables.</p