Historical Evolution of Entrepreneurial Development in the Global South: The Case of Ghana, 1957-2010

In spite of growing awareness among strategy, business history and entrepreneurship scholars of the benefits of entrepreneurial development, our understanding of the evolution of entrepreneurial development in developing nations remains limited. A historical analysis of the issue in post-colonial Ghana from 1957 to 2010 led to the identification of three distinctive phases. The first phase represented the immediate post-colonial reforms (1957–1966), where large-scale nationalisation and establishment of state-owned enterprises hampered development of private enterprises. The second phase was the turbulent period (1967–1979), where totalitarianism and confiscation of assets deterred private investments and ownership, thereby creating a harsh economic and institutional environment. These culminated in the last phase, the renaissance of social entrepreneurship (1980–2010) where different entrepreneurial models flourished, including the diaspora philanthropy and the “philanthropic chief”

Accounting for the Transitions after Entrepreneurial Business Failure: An Emerging Market Perspective

This study builds on prior scholarly works on institutions and entrepreneurship by examining the process of transitions and institutional obstacles that force serial entrepreneurs’ shift to operate in the formal or informal sector after entrepreneurial business failures. Using insights from 32 serial entrepreneurs in Ghana, a framework was developed and utilized to explicate how the pull and push motivations for the transition into or persisting with formality or informality after business failure unfolds over time. Our analysis sheds light on the processes and effects of the motivations on the persistently high level of entrepreneurial activities in the informal sector for many emerging economies

Deformation and failure mechanism of slope in three dimensions

Understanding three-dimensional (3D) slope deformation and failure mechanism and corresponding stability analyses are crucially important issues in geotechnical engineering. In this paper, the mechanisms of progressive failure with thrust-type and pull-type landslides are described in detail. It is considered that the post-failure stress state and the pre-peak stress state may occur at different regions of a landslide body with deformation development, and a critical stress state element (or the soil slice block) exists between the post-failure stress state and the pre-peak stress state regions. In this regard, two sorts of failure modes are suggested for the thrust-type and three sorts for pull-type landslides, based on the characteristics of shear stress and strain (or tensile stress and strain). Accordingly, a new joint constitutive model (JCM) is proposed based on the current stability analytical theories, and it can be used to describe the mechanical behaviors of geo-materials with softening properties. Five methods, i.e. CSRM (comprehensive sliding resistance method), MTM (main thrust method), CDM (comprehensive displacement method), SDM (surplus displacement method), and MPM (main pull method), for slope stability calculation are proposed. The S-shaped curve of monitored displacement vs. time is presented for different points on the sliding surface during progressive failure process of landslide, and the relationship between the displacement of different points on the sliding surface and height of landslide body is regarded as the parabolic curve. The comparisons between the predicted and observed load–displacement and displacement–time relations of the points on the sliding surface are conducted. The classification of stable/unstable displacement–time curves is proposed. The definition of the main sliding direction of a landslide is also suggested in such a way that the failure body of landslide (simplified as “collapse body”) is only involved in the main sliding direction, and the strike and the dip are the same as the collapse body. The rake angle is taken as the direction of the sum of sliding forces or the sum of displacements in collapse body, in which the main slip direction is dependent on progressive deformation. The reason of non-convergence with finite element method (FEM) in calculating the stability of slope is also numerically analyzed, in which a new method considering the slip surface associated with the boundary condition is proposed. It is known that the boundary condition of sliding surface can be described by perfect elasto-plastic model (PEPM) and JCM, and that the stress and strain of a landslide can be described properly with the JCM

Modélisation de l'endommagement anisotrope des roches saturées

L'objectif consistait à décrire de manière précise les comportements mécaniques et poromécaniques des grès des Vosges secs et saturés. En ce qui concerne la modélisation du comportement mécanique du grès des Vosges secs, on propose un modèle d'endommagement anisotrope induit par des microfissures. Ce modèle, basé sur les travaux précédents, décrit un comportement mécanique endommagé, en tenant compte du mécanisme du glissement et de l'ouverture des microfissures. Le potentiel complémentaire thermodynamique est caractérisé par sa dépendance linéaire par rapport à variable endommagé et par la présence d'un terme linéaire par rapport au tenseur de contrainte. L'évolution d'endommagement est liée directement à la propagation des microfissures. En particulier, un moyen pour déterminer tous les paramètres a été proposé. La vérification du modèle proposé sur divers chemins de sollicitations a montré une bonne performance. En ce qui concerne la modélisation du comportement poromécanique du grès des Vosges saturé, on développe le modèle d'endommagement anisotrope induit par des microfissures, afin de décrire les comportements poromécaniques. On adopte les paramètres d'essai de compression triaxial drainé, pour simuler les comportements d'endommagements anisotrope des roches drainées et non drainée saturée. En se basant des observations expérimentales, les contraintes effectives de Terzaghi sont utilisées avec le critère de la propagation des microfissures, afin de décrire la caractéristique de la rupture des microfissures. La formulation du potentiel thermodynamique est aussi développée, l'équation d'état peut être obtenue, en utilisant le potentiel dual. La simulation numérique montre que le modèle développé est capable de décrire les principales caractéristiques liées à l'endommagement induit par les microfissurations.LILLE1-BU (590092102) / SudocSudocFranceF

Harnessing AI for business development: A review of drivers and challenges in Africa

An accumulating body of research has demonstrated that artificial intelligence (AI) is an indistinguishable feature of the fourth industrial revolution. This study integrates the literature on AI and new technologies to examine the constraining and facilitating forces for developing and scaling-up AI-enabling technologies in Africa. This article proposes an integrated conceptual model to elucidate the range of external drivers encompassing global competitive drivers, and market and industry drivers. The internal drivers include the potential to enhance product development speed, improve quality, drive production cost down, and minimize errors and manual processes in organizations. The barriers identified include institutional dysfunction, poor infrastructure to support development of large-scale AI, lack of skilled AI experts, and lack of access to latest technologies in the regional population. The public policy implications for Africa as the potential next frontier market for AI development are discussed alongside contributions to theory

On the thermo-mechanical properties of unsaturated soils

International audienceThe establishment of energy balance equation is necessary to study the thermo-mechanical properties of unsaturated soils. To solve this equation, the determination of two fundamental parameters as volumetric specific parameter and thermal conductivity coefficient is essential. In this paper, the effective thermal conductivity coefficient of dry soil grain is analyzed for soils with different compositions, and the thermo-mechanical properties of porous media with water and gas are studied by considering the soil water retention curve (SWRC). Different methods, i.e. volumetric average method, self-consistent method, Hashin-Strikman method, are employed to calculate thermal conductivity coefficients, and a new method is proposed to determine the thermo-mechanical parameters. Comparison of the results obtained by different methods shows that the proposed method is in a good agreement with the experimental results and is suitable for describing the main properties of the thermomechanical behaviors of soils. The relationship between the SWRC and the seepage curve is further studied by the natural proportional rule. The characteristics of the SWRC, its differential coefficient and the seepage curve, are investigated by considering the physico-mechanical mechanism; the limit scopes of the indices of the SWRC and the seepage curve are also given

A New Calculation Method of Force and Displacement of Retaining Wall and Slope

On the basis of the force and safety factor analysis of traditional retaining walls, a new analytical method of force and displacement of the slope is suggested, the numerical theoretical solution of the stress distribution of the sliding body can be obtained under the conditions, which the stresses distribution are satisfied with the differential equilibrium equations, the boundary conditions, the compatibility equation and the macroscopic equilibrium equations. The interface stresses between the sliding body and the retaining wall is continuous, and the theoretical solution of retaining wall stress distributions can be obtained, while the stress differential equilibrium equation, the compatibility equation, macroscopic force, and moment balance equations are satisfied. The strain and displacement solutions can be obtained by using Duncan Chang and Hooke constitutive equations for the slope and the retaining wall, respectively. The transfer station of landfill in the Guandukou Town of Badong County is taken as an example, the results of the sliding body and retaining wall analysis show: The stress and strain solutions of a slope and a retaining wall can be obtained by the proposed method. The anti-slip force of the retaining wall calculated by the method in this paper contains the positive pressure and shear force along the contact surface and varies with the deformation of the slope, in addition, the numerical theoretical solution of the retaining wall shows that the retaining wall shape and material can be optimized according to the calculation results. It is feasible for the proposed analysis method of slope with retaining wall design to be run many years