Structural, electronic and thermoelectric properties of the intermetallic materials based on Mg2X (X= Si, Ge, Sn): DFT calculations

The scope of this work is the investigation of the physical properties of chalcopyrite materials using ab-initio methods in order to simulate a new structure of thin-films photovoltaic cells with high conversion efficiency. In the first framework, we obtained the results of calculations based on Density Functional Theory (DFT) using the full-potential linearized augmented plane wave method (FP-LAPW) as involved in the WIEN2K computational package. For the exchange-correlation potential, the local density approximation (LDA) was used to calculate the lattice parameters, Bulk modulus and its first derivative as well as the densities of states of the intermetallic semiconductors materials based on Mg2X (X=Si, Ge and Sn). The semi-local Becke-Johnson (mBJ) potential and its modified form proposed by Tran and Blaha (TB-mBJ) were also used for studying the electronic and thermoelectric properties; (merit factor, Seebeck coefficient, electronic conductivity). The achieved results were compared to computational works and other data acquired experimentally

Nonlinear predictors for systems with bounded trajectories and delayed measurements

Novel nonlinear predictors are studied for nonlinear systems with delayed measurements without assuming globally Lipschitz conditions or a known predictor map but requiring instead bounded state trajectories. The delay is constant and known. These nonlinear predictors consists of a series of dynamic filters that generate estimates of the state vector (and its maximum magnitude) at different delayed time instants which differ from one another by a small fraction of the overall delay

Algerian-Soviet relations during the period of peaceful coexistence and the location of the Palestinian cause in it 1962/1989 A.D

بدأت العلاقات الجزائرية السوفياتية عندما كان لهيب الثورة الجزائرية يمتد في نهاية الخمسينات من القرن العشرين، وتحولت بوصلتها من عداء وتأييد لدور فرنسا في الجزائر بحجة عدم التدخل في مصالح "الشعوب الفرنسية"، إلى تأييد صريح للكفاح "العادل والشرعي الذي يخوضه الجزائريون بشجاعة" ما أسهم في بناء قاعدة من التعاون الصلب والمتين بين البلدين بعد استقلال الجزائر عام 1962م،حيث تحولت الجزائر إلى بوابة للاتحاد السوفياتي في منطقة المغرب الكبير وقارة وإفريقيا، وتحول الاتحاد السوفياتي إلى "أكبر حليف" للجزائر طيلة ثلاثة عقود تقريبا، ورغم أهمية علاقاتهما، إلا أن مظاهر التوتر ظلت سائدة بينهما بسبب قلة "الحماس" السوفياتي في دعم الجزائر والعرب في معارك استرداد حقوق الشعب الفلسطيني المغتصبة ضد الكيان الصهيوني بين 1967 و1973م.Algerian-Soviet relations began when the flame of the Algerian revolution extended at the end of the fifties of the twentieth century, and its compass transformed from hostility and support for France’s role in Algeria under the pretext of non-interference in the interests of the “French peoples” to an explicit support for the “just and legitimate struggle that the Algerians are waging with courage.” What contributed In building a base of solid and solid cooperation between the two countries after the independence of Algeria in 1962.  As Algeria turned into a gateway to the Soviet Union in the Maghreb, continent and Africa, and the Soviet Union turned into Algeria's "biggest ally" for nearly three decades, despite the importance of their relations, The manifestations of tension continued to prevail between them due to the lack of Soviet "enthusiasm" in supporting Algeria and the Arabs in the battles to restore the rights of the usurped Palestinian people against the Zionist entity between 1967 and 1973

Étude observationnelle des effets associés à divers agents de sédation et d'analgésie administrés en période périopératoire chez les nourrissons atteints d’une cardiopathie congénitale complexe sur l’EEG et le neurodéveloppement

Les cardiopathies congénitales (CC) représentent l’une des anomalies congénitales les plus communes. Près de la moitié des nouveau-nés atteints nécessitent une chirurgie cardiaque au cours de leur premier mois de vie, ce qui les expose à un risque accru d’atteintes cérébrales et a été associé à un développement neurologique altéré. Il est donc nécessaire de trouver des stratégies neuroprotectrices efficaces pour améliorer leur évolution neurologique. Ce mémoire décrit l’influence des doses d’agents pharmacologiques administrées en période périopératoire sur la récupération de l’EEG en postopératoire, ainsi que sur les résultats neurodéveloppementaux évalués à 12 et 24 mois. Nous avons émis l'hypothèse que l’administration de certains agents pharmacologiques de sédation, d’anesthésie et d’analgésie en période intra- et postopératoire pourrait avoir un effet bénéfique au niveau de la récupération cérébrale à court- et long-terme, soit en réduisant la discontinuité observée sur l’EEG postopératoire et/ou en améliorant la performance obtenue lors de divers tests neurodéveloppementaux standardisés. Nos résultats semblent préconiser l’administration de plus fortes doses d’opioïdes en période périopératoire pour réduire la douleur et le stress induit par la chirurgie cardiaque, ce qui serait associé avec une amélioration du pronostic neurodéveloppemental. L’administration de plus fortes doses de dexmédétomidine et de midazolam était marquée par une récupération retardée de l’activité cérébrale après la chirurgie cardiaque sans aucun impact remarquable sur les résultats neurodéveloppementaux dans notre cohorte. Similairement, les doses de kétamine n’ont eu aucun impact sur la récupération cérébrale post-opératoire ou les bilans neurodéveloppementaux.Congenital heart disease (CHD) is one of the most common congenital defects. Almost half of neonates affected require heart surgery during their first month of life, which exposes them to an increased risk of brain damage and has been associated with impaired neurodevelopment. It is therefore important to identify effective neuroprotective strategies to improve their neurological outcomes. This thesis describes the influence of the administration of pharmacological agents during the perioperative period on postoperative EEG recovery and neurodevelopmental outcomes at 12 and 24 months. We hypothesized that the administration of certain pharmacological agents for sedation, anesthesia and analgesia given during the intra- and post-operative period could have a beneficial effect on cerebral recovery, by decreasing the postoperative EEG discontinuity and/or improving neurodevelopmental outcomes. Our results suggest that the administration of higher doses of opioids during the perioperative period could reduce the pain and stress induced by cardiac surgery and are thus associated with improved neurodevelopmental outcomes. The administration of higher doses of dexmedetomidine and midazolam was marked by a delayed recovery of brain activity after cardiac surgery without any noticeable impact on neurodevelopmental outcomes in our cohort. Similarly, the doses of ketamine had no impact on postoperative brain recovery and on their long-term development

Uklanjanje klortetraciklin klorhidrata foto-Fentonovim postupkom: eksperimentalna studija i ANN modeliranje

The present work aimed to study the feasibility of photo-Fenton oxidation for the degradation of chlortetracycline chlorhydrate (CTC) in aqueous solutions, as well as the modelling of system behaviour by artificial neural networks. The removal performance of CTC oxidation by the Photo-Fenton process was studied under solar radiation. Different parameters were studied, such as pH (3 to 5), and initial concentrations of CTC (0.1 to 10 mg l–1), hydrogen peroxide (1.701 to 190.478 mg l–1), and ferrous ions (2.8 to 103.6 mg l–1). Results showed that a high removal efficiency of 92 % was achieved at pH 3 under optimised conditions, such as 10 mg l–1 of CTC, 127.552 mg l–1 of H2O2, and 36.4 mg l–1 of Fe2+. The transformation of CTC molecules was proved by UV-visible and HPLC analyses, which showed that almost no CTC molecules were remaining in the treated solution. A multi-layer perceptron artificial neural network has been developed to predict the experimental removal efficiency of CTC based on four dimensionless inputs: molecular weight, and initial concentrations of CTC, hydrogen peroxide and ferrous ions. The best network has been found with a high determination coefficient of 0.9960, and with a very acceptable root mean square error 0.0108. In addition, the global sensitivity analysis confirms that the most influential parameter for the CTC removal by photo-Fenton oxidation is the initial concentration of ferrous cations with a relative importance of 33 %.Cilj ovog rada bio je ispitati razgradnju klortetraciklin klorhidrata (CTC) u vodenoj otopini foto-Fentonovim procesom, kao i modelirati ponašanje sustava primjenom umjetnih neuronskih mreža. Učinkovitost uklanjanja CTC-a foto-Fentonovim procesom ispitana je pod sunčevom svjetlošću. Proučavani su različiti parametri poput pH (3 do 5) te početnih koncentracija CTC-a (0,1 do 10 mg l–1), vodikova peroksida (1,701 do 190,478 mg l–1) i željeznih iona (2,8 do 103,6 mg l–1). Dobivena je učinkovitost uklanjanja od 92 % pri pH 3, uz 10 mg l–1 CTC, 127,552 mg l–1 H2O2 i 36,4 mg l–1 Fe2+. Koncentracija CTC-a praćena je spektrofotometrijski i tekućinskom kormatografijom, te su utvrđene neznatne koncentracije CTC-a u vodenoj otopini nakon obrade. Umjetna neuronska mreža višeslojni perceptron razvijena je za predviđanje eksperimentalne učinkovitosti uklanjanja CTC-a na temelju četiri bezdimenzionalna ulaza: molekulske mase, te početnih koncentracija CTC-a, vodikova peroksida i željeznih iona. Pronađena je najbolja mreža s visokim koeficijentom determinacije od 0,9960 i vrlo prihvatljivom srednjom kvadratnom pogreškom od 0,0108. Globalna analiza osjetljivosti potvrdila je da je najutjecajniji parametar kod uklanjanja CTC-a foto-Fentonovim procesom početna koncentracija kationa željeza s relativnom važnošću od 33 %

Pressure effects on the structural, elastic , electronic and optical properties of ZnO from first-principles calculations

First-principles calculations of the structural, electronic, optical and elastic properties of ZnO as a function of the pressure have been performed within density functional theory using Ultra soft pseudo potentials and generalized gradient approximation (GGA) for the exchange and correlation energy. Through our results, we note that the lattice constants decrease with the pressure increasing. Also, the elastic constants C11, C12, C13 and C33 and  the bulk modulus B increase with the pressure increasing. However, the elastic constants C44, the Shear modulus (G) and  Young’s modulus (E) decrease slowly with  increasing pressure, the band gap increases with the pressure increasing and ZnO has direct band. As pressure increases, the static dielectric constants ɛ1(0) and static refraction index n(0) decrease. Our calculated results are in good agreement with experimental data and other theoretical calculations.Keywords: DFT calculation, electronic, optical, elastic, under pressur

Electronic structure and magnetic properties of KXF3(X= Fe, Co, Mn, V) from ab initio calculations.

In this work we have performed first-principle calculations of the structural, electronic and magnetic properties of KFeF3, KCoF3, KMnF3, KVF3, using full-potential linearized augmented plane-wave (FP-LAPW) scheme within GGA. Features such as the lattice constant, bulk modulus and its pressure derivative are reported. Also, we have presented our results of the band structure and the density of states. The magnetic moments of KFeF3, KCoF3, KMnF3, KVF3 compounds are in most came from the exchange-splitting of X-3d orbital. Keywords: Magnetic materials; Ab initio calculations; Electronic structur

Design and frequency analysis of continuous finite-time-convergent differentiator

In this paper, a continuous finite-time-convergent differentiator is presented based on a strong Lyapunov function. The continuous differentiator can reduce chattering phenomenon sufficiently than normal sliding mode differentiator, and the outputs of signal tracking and derivative estimation are all smooth. Frequency analysis is applied to compare the continuous differentiator with sliding mode differentiator. The beauties of the continuous finite-time-convergent differentiator include its simplicity, restraining noises sufficiently, and avoiding the chattering phenomenon

Structural and elastic properties of BiOCu0.875S with Cu vacancies : A First principles study

The  structural and elastic properties of BiOCu0.875S with Cu vacancies have been investigated by using the first-principles density functional theory within the generalized gradient approximation. Population  analysis  suggests  that  the  chemical  bonding  in  BiOCu0.875S  has  predominantly  ionic  character  with  mixed covalent−ionic character. Basic physical properties, such as lattice constant, elastic constants Cij, bulk modulus B, shear modulus G, were calculated.  The  elastic  modulus E and  Poisson  ratio ν  the ratio B/G, shear anisotropy  and elastic anisotropy βc/βa  were  also  predicted.  The  results  show  that  tetragonal  phase  BiOCu0.875S  is mechanically stable and behaves in a ductile manner.

Praktični alat umjetne neuronske mreže za predviđanje kompetitivne adsorpcije bojila na polimernoj nanoarhitekturi gemini

The objective of this study was to model the removal efficiency of ternary adsorption system using feed-forward back propagation artificial neural network (FFBP-ANN). The ANN model was trained with Levenberg–Marquardt back propagation algorithm and the best model was found with the architecture of {9-11-4-3} neurons for the input layer, first and second hidden layers, and the output layer, respectively, based on two metrics, namely, mean squared error (MSE) = (0.2717–0.5445) and determination coefficient (R2) = (0.9997–0.9999). Results confirmed the robustness and the efficiency of the developed ANN model to model the adsorption process. This work is licensed under a Creative Commons Attribution 4.0 International License.Cilj ove studije bio je modelirati učinkovitost uklanjanja ternarnog adsorpcijskog sustava pomoću višeslojne unaprijedne neuronske mreže s povratnim rasprostiranjem pogreške (FFBP-ANN). Model ANN-a učen je algoritmom Levenberg–Marquardt, a najbolji model bio je s arhitekturom {9-11-4-3} neurona za ulazni, prvi i drugi skriveni sloj te izlazni sloj, na temelju dvaju metričkih pokazatelja: srednje kvadratne pogreške (MSE) = (0,2717 – 0,5445) i koeficijenta određivanja (R2) = (0,9997 – 0,9999). Rezultati su potvrdili robusnost i učinkovitost razvijenog ANN modela za modeliranje procesa adsorpcije. Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna