Institutional repository of university M'Hamed Bougara Boumerdes
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The administrative corruption: from the causes of spread to the mechanism of prevention and combatting
No full textThe administrative corruption is a serious phenomenon that affected various sectors and fields, and led to negative repercussions on the individuals and the state with its institutions. In this line, the administrative corruption is considered a criminal act. Therefore, it is necessary to move and think about how to stop its creeping and find solutions for prevention and combatting, in accordance with legal mechanisms that determine the measures and the institutions
Synthesis and characterization of MoO3: application to the photo production of oxygen under visible light
No full textOne of the most striking features of molybdenum oxide is the versatility of its catalytic properties, which are determined by the valence states of molybdenum and its coordination. It may be anticipated that MoO3 surface must contain catalytic sites which are active in different types of elementary steps. MoO3 was successfully synthesized by hydrothermal route at 400 °C, acquiring n-type conduction, due to oxygen deficiency. The single phase, elucidated by X-ray diffraction, crystallizes in an orthorhombic unit cell (Space Group (SG) Pbnm, N° 62) with a crystallite size of 12 nm. MoO3 is a direct band gap semiconductor with a forbidden band value of 2.93 eV where the electrical conduction occurs by low polaron hopping between mixed valences Mo+6/+5 with an activation energy of 0.14 eV. The thermo-power indicates n-type conduction, and confirmed by the capacitance-potential measurement; the latter gives an electrons density of 1.87 × 1020/cm3and a mobility of 1.77 × 10−6 m2/V.s. The flat band potential Vfb (0.11 VSCE) is determined from the capacitance measurement. The physical and chemical characterizations are correlated for the construction of the potential diagram in order to assess the photo electrochemical properties of MoO3 for the oxygen evolution. The valence band, is located above the O2/H2O potential ( ~ 1.3 VSCE), allowing O2 evolution upon visible light and the oxide is photocathodically protected against corrosion. An evolution rate of 0.13 mL/(mg. h) is obtained within 20 min. at optimal conditions (100 mg of catalyst and 50 °C)
Active Disturbance Rejection Control Based Sensorless Model Predictive Control for PMSM
No full textImproving tracking performance in speed controllers for permanent-magnet synchronous motor (PMSM) drive systems is critical due to internal challenges such as parameter variations, model uncertainty, and external disturbances like load changes. This paper proposes a new method that combines sensorless model predictive control (MPC) with active disturbance rejection control (ADRC), employing an extended state observer (ESO) as a key component of the ADRC. Notably, the proposed ADRC-MPC control integrates the advantages of MPC, such as good time response, high robustness against load variation, and a low effect of parameter variation in comparison to conventional control methods like field-oriented control (FOC). The ADRC-MPC reduces torque and flux ripples and also reduces torque and flux irregularities as well as current harmonics, which presents a major drawback in direct torque control (DTC). The proposed control with finite set model predictive control (FS-MPC) eliminates the PWM modulation and the complexity of continuous control set model predictive control (CCS-MPC). In the outer loop, the ADRC-MPC and the ESO present a very good solution. It presents a lower processing requirement than other controllers, especially the fuzzy logic controller (FLC), and also presents a consistent dynamic behavior across the entire operating range, contrary to the PID. The ADRC with ESO presents a promising solution to these challenges. The effectiveness of the proposed method is demonstrated through numerical simulations using MATLAB/Simulink software and experiments on a 3-kW surface-mounted PMSM drive system. both simulation and experimental results under different conditions show the effectiveness of the proposed approach
Warping and porosity effects on the mechanical response of FG-Beams on non-homogeneous foundations via a Quasi-3D HSDT
No full textThis paper suggests an analytical approach to investigate the free vibration and stability of functionally graded (FG) beams with both perfect and imperfect characteristics using a quasi-3D higher-order shear deformation theory (HSDT) with stretching effect. The study specifically focuses on FG beams resting on variable elastic foundations. In contrast to other shear deformation theories, this particular theory employs only four unknown functions instead of five. Moreover, this theory satisfies the boundary conditions of zero tension on the beam surfaces and facilitates hyperbolic distributions of transverse shear stresses without the necessity of shear correction factors. The elastic medium in consideration assumes the presence of two parameters, specifically Winkler-Pasternak foundations. The Winkler parameter exhibits variable variations in the longitudinal direction, including linear, parabolic, sinusoidal, cosine, exponential, and uniform, while the Pasternak parameter remains constant. The effective material characteristics of the functionally graded (FG) beam are assumed to follow a straightforward power-law distribution along the thickness direction. Additionally, the investigation of porosity includes the consideration of four different types of porosity distribution patterns, allowing for a comprehensive examination of its influence on the behavior of the beam. Using the virtual work principle, equations of motion are derived and solved analytically using Navier's method for simply supported FG beams. The accuracy is verified through comparisons with literature results. Parametric studies explore the impact of different parameters on free vibration and buckling behavior, demonstrating the theory's correctness and simplicity
Cours de: provinces pétrogazeifères : destiné pour les étudiants en Master 2, Géologie Pétrolière
No full textThe rhetoric of torture in Henri Alleg’s La Question
No full textDrawing essentially on David Spurr’s The Rhetoric of Empire (1993), this article discusses the discursive mechanisms that accompany the practice of torture as described in Henri Alleg’s La Question (1958). Examining the relation between these mechanisms and the broader discourses of colonialism and subjection, it shows that the inscription of colonial power on the injured and dehumanised body of the tortured is paralleled by the verbal denigration of these victims, reduced to a state of infantilism or, worse, animality, through verbal reflexes such as animalistic adjectives and tutoiement – a form of speech which consists in the use of the singular form of the second person (you) and which is usually reserved for children and those deemed not worthy of respect. More importantly, it argues that, rejecting both the victim status and the dehumanisation to which his jailers attempt to reduce him, Alleg shapes his own empowering rhetorical strategies, in turn debasing the torturers, ridiculing them, or mocking the colonial myths of chivalry and racial superiority. Instead of the latter, Alleg proposes a discourse of humanism and interracial brotherhood that conquers the violence he endures
Development of functional active films from blend of gelatin with crude orange juice pomace pectin: Test for packaging of virgin olive oil
No full textThe food packaging sector is focused on developing innovative materials to enhance food safety and quality while reducing environmental impact. Accordingly, this study aimed to develop packaging based on bovine gelatin (G) blended with crude sweet orange juice pomace pectin (SOPP) at different ratios (G/SOPP = 85/15, 65/35, 50/50, w/w). The obtained crude SOPP was highly methylated and exhibited antioxidant and antibacterial properties due to the presence of galacturonic acid (<70%) and phenolic compounds (58.2 ± 0.8 mg/g SOPP). High-performance liquid chromatography with diode array detection analysis revealed the presence of hesperidin, catechin, and naringin as major phenolic compounds in SOPP. Further, the incorporation of this latter improved gelatin-based packaging structural homogeneity, opacity, water vapour barrier features, glass transition temperature and tensile strength. G-SOPP (50/50) film showed efficient antibacterial activity against Escherichia coli and Bacillus subtilis and high antioxidant potential reaching values of 0.7, 48.7%, 76.7% and 68.9% for reducing power, β-carotene bleaching inhibition, DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS+ (2,2′-azinobis-[3-ethylbenzothiazoline-6-sulphonic acid]) radicals scavenging activities, respectively. Another interesting finding is that the combination of G and SOPP reduced the oil solubility of G-SOPP films suggesting great physical integrity of the film over 63 days. The polyphenol content released from G-SOPP blend film in a fatty simulant increased as SOPP content of films was increased. G-SOPP (50/50) film, designed as a pouch, delays the photooxidation process of virgin olive oil over 63 days of storage time, without altering its organoleptic properties. Overall, these outstanding results highlighted the potential use of gelatin–pectin blend films for active packaging of oils and lipid-based foods
Dual-Band Vertically Polarized Endfire Antenna Array for 5G NR FR2 Bands Applications
No full textIn this paper, a dual-band endfire antenna is proposed for promising 5G NR mmWave frequency (FR2) bands applications. The antenna design introduces a novel radiating aperture array analogy based on open-end substrate integrated waveguide (SIW) feeding technology to achieve vertically polarized dual-band operation. The simulated -10 dB impedance bandwidth achieves 11.5 % (26.3-29.5 GHz) lower band and 9.6 % (36.8-40.5 GHz) higher band. The peak realized gain is 8.78 dBi and 11.5 dBi in the lower and higher bands, respectively. The mmWave array delivers a scanning angle of ± 40° and ± 32° for a realized endfire gain higher than 5.5 dBi and 8.2 dBi at 28 GHz and 39 GHz, respectively.IEEE Antennas and Propagation Society (APS)Italian National Committee (ITNC)The Institute of Electrical and Electronics EngineersUS National Committee (USNC) of the International Union of Radio Science (URSI
L’Influence des crises géopolitique sur les opérations de la chaîne d’approvisionnement
No full text73 p. : ill. ; 30 cmCette thèse explore le rôle crucial de la géopolitique et de l'énergie dans les dynamiques mondiales contemporaines. Elle examine comment les nations négocient, coopèrent ou rivalisent pour l'accès aux ressources énergétiques, leur transport et leur distribution. L'étude approfondit les implications géopolitiques de l'énergie, soulignant comment ces questions influencent les relations internationales et les politiques nationales. De plus, elle aborde la transition vers des sources d'énergie durables et les nouvelles dynamiques de pouvoir. La recherche se concentre également sur la gestion de la chaîne d'approvisionnement dans le marché des services pétroliers, détaillant les processus de l'extraction à la distribution. En analysant le cas de National Energy Services Reunited (NESR), la thèse met en avant l'importance d'une gestion efficace de la chaîne d'approvisionnement pour optimiser les coûts, améliorer la qualité et assurer la satisfaction des clients
Caractérisation et prédiction du dépôt d’Asphaltène d’un pétrole brute algérienne
No full text91 p. : ill. ; 30 cmLa Production de pétrole et de gaz fait face à de multiples problèmes, dont le dépôt d’Asphaltènes dans le réservoir. Ce problème est dû à de nombreux facteurs affectant la stabilité du pétrole brut produit, qu’il s’agisse de la composition du pétrole lui-même ou du changement de pression lors de la production. Plusieurs tests ont été effectués pour comprendre ce comportement et pour déterminer quelle méthode est la plus précise. Ces tests étaient le test SARA, le test AOP, le titrage au n-heptane et le calcul des valeurs P et S. Chaque méthode avait ses utilisations, ses hauts et ses bas. L'AOP a été considéré comme le plus utile pour déterminer l'effet de la pression sur la précipitation des Asphaltènes, et le titrage au n-heptane est un bon test pour déterminer la stabilité du pétrole brut grâce à un agent peptisant