Search

Mixed organic and mineral deposits clogging perforations in the near wellbore area is a significant problem in the oil and gas industry. Matrix acidizing is widely applied to relieve this damage in the Haoud Berkaoui region using three different acid systems proposed by company services to restore the initial properties. This work aims to understand and interpret the history to investigate the efficient acid system adapted to the reservoir of two candidate wells. Different data are collected and analyzed. However, laboratory tests were conducted to verify the performance of each acid. Matching laboratory results, Acid Response Curves (ARC) interpretation, and microscopic photos with field data analysis show that only one mud acid system (6% HCl-1.5% HF) among the three is adequately used in the field to minimize the skin factor. It also increases the relative permeability in the wellbore region (7 for well N1 and 3.7 for well N2) and a flow rate gain (0.25 m3/h for the well N2). This study allows the best acid selection and suitable additives for maximum oil recovery of wells, solving problems associated with the production of wells and decreasing the cost of the operation in the future. [ABSTRACT FROM AUTHOR]

Proximal humeral fractures are among the most common fractures seen in emergency departments. Accurately diagnosing and selecting the most appropriate treatment for these fractures can be challenging, and consultation with a senior orthopedic surgeon can be time-consuming for both the patient and the emergency unit. We developed a machine learning model for predicting the type of treatment based on injury radiographic images. The model distinguishes between nonoperative and operative treatment options, achieving an accuracy of 86% and an interobserver reliability (kappa) of 0.722 for test-dataset, which is more than the interobserver agreement between shoulder surgeons. This model has the potential to serve as a therapeutic decision support system for the practitioners in the emergency departments to expedite treatment decisions and to reduce patients' waiting time. [ABSTRACT FROM AUTHOR]

Proportional, Integral and Derivative (PID) controllers are the most popular type of controller used in industrial applications because of their notable simplicity and effective implementation. However, manual tuning of these controllers is tedious and often leads to poor performance. The conventional Ziegler-Nichols (Z-N) method of PID tuning was done experimentally enables easy identification stable PID parameters in a short time, but is accompanied by overshoot, high steady-state error, and large rise time. Therefore, in this study, the modern heuristics approach of Particle Swarm Optimization (PSO) was employed to enhance the capabilities of the conventional Z-N technique. PSO with the constriction coefficient method experimentally demonstrated the ability to efficiently and effectively identify optimal PID controller parameters for attitude stabilization of a quadrotor.

Fuzzy gain-scheduled PID (FuGSPID) controllers have attracted significant interest in contemporary research. This paper provides mathematical description help to reduce the code program for a Fuzzy gain-scheduled controller FuGSPID that is subsequently used to stabilize the altitude of a home-constructed Quadcopter. The subject particle swarm optimization approach was employed to optimize the fuzzy output sets of the controller. MATLAB was used to generate the dynamic model, the FuGSPID, and the optimization. A simulation exercise revealed that the new parameters employed in the FuGSPID that were generated as a result of the particle swarm optimization produced fewer trajectory tracking errors. Fuzzy systems are required to process large volumes of tasks and processes. This subsequently impedes the performance of the microcontroller. In light of this, this paper outlines a mathematical description that can potentially reduce the algorithm code employed in the FuGSPID controller and, thereby, making it more intuitive and reducing the processing speed of the microcontroller and reducing the sampling time of the controller and the whole flight controller. The findings of this study revealed that the mathematical description it be useful to reduce instruction of fuzzy controller program to implement it in low cost microcontroller and tested effectively for a quadcopter altitude stabilization. [ABSTRACT FROM AUTHOR]

The intention of this research is to provide tuning for the coefficients of the switching sliding manifold for the second-order sliding mode employing Particle Swarm Optimization. This research was carried out in noisy conditions with a homemade prototype apparatus employing cheap componentry. A Teensy development board was used as flight controller for a quadcopter, with the second-order sliding mode controller being used for attitude stabilization. Other research has offered confirmation for the control law in both theory and simulation where they identify the nonlinear coefficients based on Hurwitz stability analysis and linearization around equilibrium point. But in this research, we shall be focusing upon identification of the coefficients for the switching siding manifold of the second-order siding employing Particle Swarm Optimization, the obtained coefficient validated both practically and experimentally; this has never previously been undertaken. New data samples will also be provided regarding the short time execution for the physical system; this data will prove useful for future applications using artificial intelligence. The outcomes of the research demonstrate that the proposed tuning method for second order sliding mode controller confirm its robustness and effectiveness both in simulation and experiment. [ABSTRACT FROM AUTHOR]

The structural, elastic, electronic, vibrational, and optical properties of BaSe1−xTex alloys are investigated by means of the full-potential linearized augmented plane wave method. The exchange-correlation effects are treated with the local density approximation, as well as the GGA-PBE, GGA-PBEsol, and GGA + mBJ schemes of the generalized gradient approximation. Ternary BaSe1−xTex compounds have not yet been synthesized. Improved predictions of the structural parameters are obtained using the GGA-PBEsol approach. Calculations of the electronic and optical properties with the GGA + mBJ approach yield accurate results. Ternary BaSe1−xTex alloys are wide-band-gap semiconductors with a direct gap Γ-Γ. The upper valence band is mainly due to Se p and Te p states, while the bottom of the conduction band results essentially from Ba d states. The dielectric function, refractive index, reflectivity, absorption coefficient, and energy-loss function are calculated in the range 0-35 eV. The increase in x gives rise to a redshift of the optical spectra. BaSe1−xTex alloys exhibit reflective properties of metals in some energy ranges. The static dielectric constant ɛ1(0) and the static refractive index n0 are calculated. The investigation of the elastic and vibrational properties shows that ternary BaSe1−xTex should be mechanically and dynamically stable, elastically anisotropic, brittle, and relatively soft. [ABSTRACT FROM AUTHOR]

The structural, elastic, electronic and magnetic properties of the MnRhSi Mn-based Heusler alloy were investigated by using first-principles calculations of the full-potential linearized augmented plane wave (FP-LAPW) method. The results of electronic structures show that the MnRhSi exhibits a half-metallic character for a wide range 5.65 to 5.91 Å of lattice constant. The half-metallic behavior is confirmed by the integral value of 3 μ of the total magnetic moment for MnRhSi, which follow the Slater-Pauling rule. [ABSTRACT FROM AUTHOR]

We have performed first-principles calculations of structural, elastic, thermodynamic, and electronic properties of anti-perovskites ACNi (A = Al, Ga, In), by using the full-potential linearized augmented plane wave (FP-LAPW) method combined with the quasi-harmonic Debye model. We carried out our calculations within the local density approximation (LDA) and the generalized gradient approximation (GGA-PBE and GGA-PBEsol functionals). Our results constitute interesting first predictions in the case of many elastic parameters of the anti-perovskites ACNi, among them elastic parameters of AlCNi and GaCNi and some polycrystalline elastic parameters of InCNi. We also report for the first time calculated values, at ambient conditions, of Grüneisen parameter, thermal expansion coefficient, specific heat at constant pressure, specific heat at constant volume, isothermal bulk modulus, and adiabatic bulk modulus for AlCNi, GaCNi, and InCNi. Band structure, total and partial densities of states, and charge density have been obtained and analyzed. Electronic structure results show metallic behavior for the three compounds. Ni 3 d states play dominant role near the Fermi level and there is a strong hybridization between Ni 3 d and C 2 p states. In addition, as ACNi synthesized samples are expected to be carbon-deficient, we calculated structural, elastic, and thermodynamic properties of sub-stoichiometric AlCNi materials. [ABSTRACT FROM AUTHOR]