Electronic and optical properties of metal-doped TiO2_2 nanotubes: Spintronic and photocatalytic applications

Due to their characteristic geometry, TiO$_2$ nanotubes (TNTs), suitably doped by metal-substitution to enhance their photocatalytic properties, have a high potential for applications such as clean fuel production. In this context, we present a detailed investigation of the magnetic, electronic, and optical properties of transition-metal doped TNTs, based on hybrid density functional theory. In particular, we focus on the $3d$, the $4d$, as well as selected $5d$ transition-metal doped TNTs. Thereby, we are able to explain the enhanced optical activity and photocatalytic sensitivity observed in various experiments. We find, for example, that Cr- and W-doped TNTs can be employed for applications like water splitting and carbon dioxide reduction, and for spintronic devices. The best candidate for water splitting is Fe-doped TNT, in agreement with experimental observations. In addition, our findings provide valuable hints for future experimental studies of the ferromagnetic/spintronic behavior of metal-doped titania nanotubes.Comment: 25 pages (preprint style), 10 figure

Essai de mesure de la performance globale des entreprises : Cas des entreprises nationales du secteur du textile et d’habillement

Currently, the issue of overall performance is at the center of the new managerial strategies of each organization. Its delimitation is very difficult because of the two levels of reality to which it refers: overall performance is both the objective and the main tool of the strategic visions of organizations. These two main axes of reality are extremely linked since the analysis of performance as the main objective of private sector companies particularly leads to the implementation of performance measures. Also, the concept of performance is used to analyze, on the one hand, the by companies of the objective of sustainable development, and to verify the achievement of financial, social and societal performance, on the other hand. The problem of performance is not limited solely to the quantitative analysis of the variations in the results, but to the optimization of the determination of all the qualitative factors which contribute to the achievement of these objectives. Indeed, the objective of performance is not only about achieving the objectives set, but they must be achieved at the lowest cost. Thus, the measures are an opportunity to define, explain and create performance measures. Our objective, therefore, through this study, is to measure, on the one hand, the overall performance of national companies in the textile and clothing sector by determining composite indices, and on the other hand, to measure the structural level of each axis retained as a measure of a specific typology of performance. According to our study and on the basis of principal component factor analyzes and our predictive model, the performance measurement is multidimensional, and multi-level.     JEL Classification : B23, M16, M11, M21, O31 Paper type: Empirical researchActuellement, la problématique de la performance globale est au centre des nouvelles stratégies managériales de chaque organisation. Sa délimitation est très difficile du fait des deux niveaux de réalité auxquels elle fait référence : la performance globale est à la fois l’objectif et le principal outil des visions stratégiques des organisations. Ces deux principaux axes de réalité sont extrêmement liés puisque l’analyse de la performance comme principal objectif des entreprises du secteur privé induit particulièrement à la mise en œuvre de mesures de la performance. Également, le concept de la performance est utilisé pour l’analyse d’une part l’opérationnalisation par les entreprises de l’objectif de développement durable, et de vérifier l’atteinte de la performance financière, sociale et sociétale d’autre part. Ainsi, La problématique de la performance ne se limite pas uniquement à l’analyse quantitative des variations les résultats, mais à l’optimisation de la détermination des facteurs qualitatifs qui contribuent à la réalisation de ces objectifs. En effet, l’objectif de la performance n’est pas uniquement d’aboutir aux objectifs fixés, mais il faut les atteindre aux moindres coûts). C’est ainsi, les mesures sont l’occasion de définir, expliciter et créer des mesures de performance. Notre objectif donc à travers la présente étude, à partir d’une enquête sur 231 entreprises du secteur du textile et d’habillement est de mesurer d’une part, la performance globale des entreprises nationales du secteur du textile et d’habillement par la détermination des indices composites, et d’autre part, mesurer le niveau structurel de chaque axe retenu comme mesure d’une typologie de la performance. Sur la base des analyses factorielles en composantes principales, et notre modèle prédictif, la mesure de performance est de nature multidimensionnelle et multiniveaux.     EL Classification : B23, M16, M11, M21, O31 Type de papier : Recherche empiriqu

Déterminants de Management de qualité dans les entreprises Nationales : Cas des entreprises du secteur du textile et d’habillement

Quality management is a major concern for all companies, allowing efficient, effective and secure operation of the various operating processes. The implementation of an adequate quality management system allows functional modernization, cost control and determination of the risks related to the company's activity. In Morocco, the adoption of the new policy based on quality management aims to modernize national companies, consolidate their competitive position, and develop their quality system through several programs designed for this purpose. The purpose is twofold: firstly to confirm their missions as citizen economic agents in the creation of national wealth and sustainable development, and secondly to achieve a substantial market share in accordance with their strategic vocations. The interest of this work is therefore to analyze the determinants of the quality system in national companies: Case of the textile and clothing sector. This interest is treated from a review of conceptual, theoretical and empirical literature on the need for the implementation of quality approaches in the management of companies. Also, the objective of this work from a survey of 231 companies in the said sector is to show that the quality management system is based on a set of resources and which makes it possible to group, classify, process and to disseminate information. Thus, according to our study, among the main determinants of an efficient management system: the size of the company, the organizational analysis, the environmental analysis, the information systems and the commercial strategies. Finally, via a binary logistic regression, we showed that these factors have a crucial role in the modernization of total quality management.     JEL Classification : B23, M16, M11, M21, O31 Paper type: Empirical researchLe management de la qualité est une préoccupation majeure pour toutes les entreprises, permettant un fonctionnement efficient, efficace et sécurisé des différents processus d’exploitation. La mise en place d’un système de management de qualité adéquat permet une modernisation fonctionnelle, une maitrise des coûts ainsi qu’une détermination des risques liés à l’activité de l’entreprise. Au Maroc, l’adoption de la nouvelle politique basée sur le management de la qualité vise la modernisation des entreprises nationale, la consolidation de leur position concurrentielle, et le développement de leur système de qualité par plusieurs programmes conçus à cette fin. L’objet étant double : d’abord confirmer leurs missions d’agent économique citoyen dans la création de la richesse nationale, et au développement durable, et d’autre part réaliser une part du marché conséquente conformément à leurs vocations stratégiques.  L’intérêt de ce travail est donc d’analyser les déterminants du système de qualité dans les entreprises nationales : Cas du secteur du textile et d’habillement. Cet intérêt est traité à partir d’une revue de littérature conceptuelle, théorique et empirique sur la nécessité de l’implémentation des démarches de qualité dans le management des entreprises. Également, l’objectif de ce travail à partir d’une enquête sur 231 entreprises dudit secteur est de monter que le système de management de la qualité se base sur un ensemble des ressources et qui permet de regrouper, de classifier, de traiter et de diffuser de l'information.  Ainsi, d’après notre étude, parmi les principaux déterminants d’un système de management performant : la taille de l’entreprise, l’analyse organisationnelle et environnementale, les systèmes d’information et les stratégies commerciales. Enfin, via une régression logistique binaire, nous avons montré que ces facteurs ont un rôle crucial dans la modernisation de management de qualité totale.     JEL Classification : B23, M16, M11, M21, O31 Type de papier : Recherche empiriqu

Sparsity-based Recovery of Finite Alphabet Solutions to Underdetermined Linear Systems

International audienceWe consider the problem of estimating a deterministic finite alphabet vector f from underdetermined measurements y = A f, where A is a given (random) n x M matrix. Two new convex optimization methods are introduced for the recovery of finite alphabet signals via l1-norm minimization. The first method is based on regularization. In the second approach, the problem is formulated as the recovery of sparse signals after a suitable sparse transform. The regularization-based method is less complex than the transform-based one. When the alphabet size $p$ equals 2 and (n,N) grows proportionally, the conditions under which the signal will be recovered with high probability are the same for the two methods. When p > 2, the behavior of the transform-based method is established. Experimental results support this theoretical result and show that the transform method outperforms the regularization-based one

Response to Comment on (Novel two-dimensional porous graphitic carbon nitride C6N7 monolayer: A First-principle calculations [Appl. Phys. Lett. 2021, 119, 142102])

Recently, reported a comments on the our paper [Appl. Phys. Lett. 119, 142102 (2021)]. With our response, the APL journal rejected their non scientific comments. There are some ambiguities about their claim: 1-They can check the phonon dispersion of their structure to see ZA out-of-plane mode. 2-They report the uniaxial stress-strain responses in Fig 2., which is unrelated to our paper. For a more helpful understanding of the mechanical properties of the novel C6N7 monolayer, they can publish a paper. 3-They mentioned: Using the DFT method and with assuming a thickness of 3.35 A for the C6N7 monolayer based on graphene thickness. Why did they choose this thickness while we know our C6N7 monolayer is at without buckling? The distance of ZA out-of-plane movement of ions in C6N7 is different from Graphene.Comment: 1 pag

Optimization Of The Electronic And Optical Properties Of Tio2 For Clean Fuel Production

Among different crystal structures and morphologies of TiO2, vertically oriented anatase nanotube arrays show the highest activity for solar energy conversion. However, the long-standing bottleneck is the fact that TiO2 is a wide band gap semiconductor, limiting its activation to the deep-blue and ultraviolet spectral region that contains but a small fraction (5%) of the incident solar energy. Herein, density functional theory (DFT) has been used to compare between density of states of bulk and nanotube forms of TiO2 by using different concentrations of N atoms. The wave functions were described using two different techniques; linear combination of atomic orbital (LCAO) and plane wave. Our results showed a shift in the calculated bandgap for bulk TiO2 only for small concentrations of N atoms as dopant. For TiO2 nanotube, the bandgap decreases as the concentration of N atoms increases. The effect of the diameter of TiO2 nanotubes on their optical and structural properties has also been investigated and discussed in details. Our study presents a protocol to fine tune the optical, electronic and structural properties of TiO2 for energy conversion applications.qscienc

Effects of alirocumab on types of myocardial infarction: insights from the ODYSSEY OUTCOMES trial

Aims  The third Universal Definition of Myocardial Infarction (MI) Task Force classified MIs into five types: Type 1, spontaneous; Type 2, related to oxygen supply/demand imbalance; Type 3, fatal without ascertainment of cardiac biomarkers; Type 4, related to percutaneous coronary intervention; and Type 5, related to coronary artery bypass surgery. Low-density lipoprotein cholesterol (LDL-C) reduction with statins and proprotein convertase subtilisin–kexin Type 9 (PCSK9) inhibitors reduces risk of MI, but less is known about effects on types of MI. ODYSSEY OUTCOMES compared the PCSK9 inhibitor alirocumab with placebo in 18 924 patients with recent acute coronary syndrome (ACS) and elevated LDL-C (≥1.8 mmol/L) despite intensive statin therapy. In a pre-specified analysis, we assessed the effects of alirocumab on types of MI. Methods and results  Median follow-up was 2.8 years. Myocardial infarction types were prospectively adjudicated and classified. Of 1860 total MIs, 1223 (65.8%) were adjudicated as Type 1, 386 (20.8%) as Type 2, and 244 (13.1%) as Type 4. Few events were Type 3 (n = 2) or Type 5 (n = 5). Alirocumab reduced first MIs [hazard ratio (HR) 0.85, 95% confidence interval (CI) 0.77–0.95; P = 0.003], with reductions in both Type 1 (HR 0.87, 95% CI 0.77–0.99; P = 0.032) and Type 2 (0.77, 0.61–0.97; P = 0.025), but not Type 4 MI. Conclusion  After ACS, alirocumab added to intensive statin therapy favourably impacted on Type 1 and 2 MIs. The data indicate for the first time that a lipid-lowering therapy can attenuate the risk of Type 2 MI. Low-density lipoprotein cholesterol reduction below levels achievable with statins is an effective preventive strategy for both MI types.For complete list of authors see http://dx.doi.org/10.1093/eurheartj/ehz299</p