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This study aims to determine the maximum extent of damage in the threat zones, the result of a catastrophic failure in one liquefied petroleum gas storage sphere, located in storage and transfer center in Hassi R’Mel city, Algeria.

To reach the desired results, we relied on ALOHA® v. 5.4.7 software (Areal Locations of Hazardous Atmospheres) for accidents simulation, and on Google Earth as an output tool to show results on the city map.

The results prove that the city of Hassi R’Mel is almost completely threatened by thermal effects resulting from a boiling liquid expanding vapor explosion phenomenon, which can reach a distance of 3.9 km.

Determining the extent to which the damages resulting from an industrial accident may reach is of great importance in preventing industrial hazards, as well as in decision-making in the field of urbanization.

Reactive powder concretes (RPCs) are new concretes characterized by a particle diameter not exceeding 600 µm and very high compressive and tensile strengths. This paper aims to the development and study of the physico-mechanical, elastic properties and durability of an ultra-high performance concrete from materials existing on the Algerian market.

Three mineral additions such as granulated slag, quartz powder and silica fume are incorporated into the cement with 15, 23 and 25 per cent, respectively, in addition to use two different values of steel fiber volume fraction (2 and 2.5 per cent). The results show that the incorporation of 2.5 per cent metal fibers in the formulation of the RPC gives a high compressive strengths of 143.5 MPa at 60 days. The relationship between the relative value and the longitudinal elasto-instantaneous deformations of the RPC to a linear characteristic throughout the relative stress ranges. Also, the modulus of elasticity developed for a fiber-reinforced reactive concrete is greater than that of the unbound fiber.

Results from the current study concluded that the presence of the mineral additions improves the durability of the concretes compared with that not adjuvanted by mineral additions.

It can be possible to manufacture fiber-reinforced reactive powder concretes (RPCFs) with compressive strength exceeding 140 MPa, with an adequate plasticity, despite the simplicity of means and materials and the incorporation of different percentage of metal fiber on the mechanical strength of concretes and its influence on behavior with respect to aggressive environment were achieved.

Leadership is basically about influence and ability to cultivate followership. This chapter examined the nature of indigenous socio-political leadership in Africa using Zimbabwe, Sudan and Nigeria as caselets and compared this with the post-colonial or modern-day leadership realities. A survey was conducted among senior executives at Lagos Business School, Nigeria, with a sample size of 200 persons, to find out their perception of the African indigenous leadership system. An overwhelming 90% believe that culture plays a big role in shaping African leadership style. However, two-thirds of the respondents agreed that Africa lacks proper institutional structures to support good leadership, thus encouraging corruption (97% of the respondents) and non-accountability among the leaders. Also, only 5% thought cultural orientation was the reason why the African followers do not hold their leaders accountable. In other words, it is not in the African culture not to hold leaders accountable for their actions. So, what went wrong? We attempted a deeper look at the effect of colonial rule and the attendant militarisation of the African continent. Our conclusion is that the colonisation of the continent by Europe brought significant distortion to the traditional African indigenous leadership institutions and the psyche of the African leader and the followers alike. Post-colonial Africa has witnessed 133 recorded coups d’etat between 1952 and 2016. This chapter is recommended to all those who seek a deeper understanding of the nature of the African indigenous leadership practices and the factors that have shaped these over the years.

Nonlinear systems identification from experimental data without any prior knowledge of the system parameters is a challenge in control and process diagnostic. It determines mathematical model parameters that are able to reproduce the dynamic behavior of a system. This paper aims to combine two fundamental research areas: MIMO state space system identification and nonlinear control system. This combination produces a technique that leads to robust stabilization of a nonlinear Takagi–Sugeno fuzzy system (T-S).

The first part of this paper describes the identification based on the Numerical algorithm for Subspace State Space System IDentification (N4SID). The second part, from the identified models of first part, explains how we use the interpolation of linear time invariants models to build a nonlinear multiple model system, T-S model. For demonstration purposes, conditions on stability and stabilization of discrete time, T-S model were discussed.

Stability analysis based on the quadratic Lyapunov function to simplify implementation was explained in this paper. The linear matrix inequalities technique obtained from the linearization of the bilinear matrix inequalities was computed. The suggested N4SID2 algorithm had the smallest error value compared to other algorithms for all estimated system matrices.

The stabilization of the closed-loop discrete time T-S system, using the improved parallel distributed compensation control law, was discussed to reconstruct the state from nonlinear Luenberger observers.

The drill string vibrations can create harmful effects on drilling performance because they generate the stick-slip phenomenon which reduces the quality of drilling and decreases the penetration rate and may affect the robustness of the designed controller. For this reason, it is necessary to carefully test the different rock-bit contact models and analyze their influences on system stability in order to mitigate the vibrations. The purpose of this paper is to investigate the effects of rock-bit interaction on high-frequency stick-slip vibration severity in rotary drilling systems.

The main objective of this study is an overview of the influence of the rock-bit interaction models on the bit dynamics. A total of three models have been considered, and the drilling parameters have been varied in order to study the reliability of the models. Moreover, a comparison between these models has allowed the determination of the most reliable function for stick-slip phenomenon.

The torsional model with three degrees of freedom has been considered in order to highlight the effectiveness of the comparative study. Based on the obtained results, it has been concluded that the rock-bit interaction model has big influences on the response of the rotary drilling system. Therefore, it is recommended to consider the results of this study in order to design and implement a robust control system to mitigate harmful vibrations; the practical implementation of this model can be advantageous in designing a smart rotary drilling system.

Many rock-bit functions have been proposed in the literature, but no study has been dedicated to compare them; this is the main contribution of this study. Moreover, a case study of harmonic torsional vibrations analysis has been carried out in well-A, which is located in an Algerian hydrocarbons field, the indices of vibrations detection are given with their preventions.