In this investigation, we have conducted a comprehensive analysis of NdPd compound, focusing on its fundamental properties, magnetic behavior, and potential for magnetocaloric applications. The approach involved a combination of ab-initio calculations and MCs. Notably, the computed magnetic moment for the Nd atom stands at 3.11µB, close to the experimental value. Moreover, the exchange couplings of Nd-Nd interactions have unearthed intriguing insights: the initial two exchange couplings (J1= 1.593 meV and J2=-0.358 meV) exhibit positive signs, indicative of ferromagnetic tendencies. Another result from our simulations is the discovery of ferromagnetic ordering within the NdPd compound, which takes place at a critical temperature (Tc of 16K. Additionally, we observed the isothermal magnetic entropy in a 5T magnetic field around the Curie temperature, exhibiting remarkable agreement with laboratory results. This discovery implies that utilizing NdPd for magnetic refrigeration can show significant potential for effectively cooling cryogenic systems operating within temperatures below 20K.

Considering the temporary ecological challenges confronting our global milieu, the imperative to transition towards sustainable and conscientious methodologies looms as an unequivocal necessity. As purveyors of scientific inquiry our mandate is to meticulously explore a plethora of alternatives, liberating ourselves from the shackles of deleterious energy sources. We are investigating the value of semiconducting polymer-based solar cells in this work from a material science perspective because they are quite affordable to synthesize and have demonstrated some encouraging results, due to its notable benefits in photovoltaic (PV) applications, such as its high absorption coefficients, excellent charge carrier mobility, and favorable blend morphology with acceptor materials, which all contribute to improved device performance. We are using poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) in this study. In order to investigate the impact of the Methylammonium Lead Iodide Perovskite (MAPI3) thin film on the performance of the ITO/TiO2/MEH-PPV/Au solar cell, a numerical simulation was carried out using SCAPS-1D. Open circuit voltage (Voc), density of short circuit (Jsc), fill factor (FF), efficiency (η), and other solar cell metrics were measured and analyzed, with special emphasis to device inputs and the ensuing improvements. The performance of the MEH-PPV/TiO2 solar cell has been enhanced by the addition of MAPI3, resulting in a noteworthy 14% efficiency boost. These modelling results can be very useful for a better understanding and control of this type of solar cells.

Indentation, avances exprimentales et de modlisation Indentation advances in experiments and modellingDu 4 au 7 juillet 2023, l'Universit de Tours, s'est tenu le colloque Indentation 2023, neuvime dition de ce congrs francophone organis tous les deux ans.Le colloque a runi tous les scientifiques utilisateurs avancs des techniques d'indentation instrumente.Ces techniques d'indentation statique ou dynamique sont utilises largement par l'industrie pour caractriser les surfaces de matriaux fonctionnaliss.Ces techniques rcentes ne sont pas encore au stade des essais conventionnels de caractrisation des matriaux massifs.C'tait justement l'objet du colloque Indentation 2023 : faire un tat des lieux des aspects exprimentaux et des modlisations en cours dans le domaine tout en mettant la lumire sur l'application dans le domaine des Polymres, lastomres et bio-matriaux.Durant ce colloque, qui a runi une centaine de participants issus des quipes franaises et europennes possdant des quipements instrumentaux et/ou des moyens numriques ddis aux techniques d'indentation, environ une trentaine de prsentations orales et une vingtaine de posters ont t prsents.L'ensemble de ces travaux prsents lors de 7 sessions a suscit de nombreuses discussions et changes entre les participants.La formation sur l'indentation comprenait quatre sessions et tait organise en amont du colloque (https://indentation2023.sciencesconf.org/resource/page/id/2).Une session exprimentale a pu tre organise fort de la participation des fabricants de machine que nous remercions vivement.Fort du succs rencontr encore une fois par le colloque et la formation, une nouvelle dition sera organise Besanon en France.Chaque dition du colloque a donn lieu un numro spcial dans la revue Matriaux et Technique [1][2][3][4][5][6][7][8].Inscrit dans cette tradition, nous prsentons dans ce numro thmatique, un ensemble d'articles issus d'une slection de contributions au colloque, publis aprs un processus d'valuation et de rvision.Ces articles offrent un aperu de toutes les thmatiques abordes au cours du colloque.L'ensemble du numro regroupe des travaux fondamentaux et appliqus et permet de faire un point sur des sujets d'actualit dans le domaine de l'indentation.

A puzzling matter about materials, particularly structural materials, is that they exhibit both a rather extraordinary extension in time, bridging over many historical and prehistorical ages, and a dynamic dimension, changing as they are in time to the point that materials may not be easily recognized as similar today as thousands of years ago. To understand this dichotomy, it is necessary to reach beyond materials science and STEM disciplines and to collect concepts and methods from SSH. Materials and energy are at the core of the physical world in which society functions: they provide the structure of the artifacts that we need, along with the ability to make and use them. They do not exist in an absolute, Aristotelian world, but are invented along historical time, by people to meet their needs, hic et nunc. Materials are social constructs, as is the “theory” (technology, science in modern language) that gives us the keys for making them. As society changes historically, people’s needs evolve and “new” materials are created on the shoulders of older ones, in a kind of evolutionary process. This is the view of social constructivism. This evolutionary metaphor is a first explanation of the continuity between, say, iron from a Roman bloomery and steel, as a contemporary commercial product. This has been formulated as the Social Cycle of Materials (SCM) by sociologists of Knowledge and Innovation, as a process of continuous innovation in which materials are socially constructed over and over again, a process often called “progress”. The continuity from old to new materials needs to be explained by some other model, however, to be fully understood: indeed, why is iron enduring so much, when it might have been displaced by another material at each evolutionary step and it didn’t. The explanation we propose is to accept that “materials have agency”, i.e. that they themselves are the actors of their own perenniality. This refers to another model, the Actor Network Theory (ANT) of Latour et al., which analyzes how change is pulled by a combined network of actors, that include people, organizations, non-human living entities and inanimate things as well.

Poly (vinyl chloride)/ montmorillonite nanocomposites were prepared using a melt mixing technique. For this purpose, three montmorillonite samples (MMT) namely, raw montmorillonite (R-MMT), sodium montmorillonite (Na+-MMT) and organically modified montmorillonite (O-MMT) were used with different contents (0, 1, 3, 5, 7 and 9 phr) in the presence of dioctyl phthalate (DOP). X-Ray Diffraction (XRD), Atomic Force Microscopy (AFM), Differential Scanning Calorimetry (DSC), and mechanical testing were used to investigate the physical properties of nanocomposites (PVC/MMT). The results of XRD show that macromolecule chains of PVC may be intercalated or exfoliated into the gallery of modified montmorillonite (Na+-MMT and O-MMT). Microcomposites structure is formed on the PVC/R-MMT nanocomposites when the unmodified montmorillonite (R-MMT) content is added from 1 to 9 phr. However, the glass transition temperature (Tg) of PVC/O-MMT nanocomposites is shifted slightly to lower temperatures. Furthermore, O-MMT plays the role of an internal plasticizer hence increases the distance between macromolecule chains of the polymer. Consequently, the degree of interactions between the chains decreases inducing a decrease in Tg. Synergy effect is also observed on the PVC/O-MMT nanocomposites with the increase in the amount of O-MMT. The morphological study by AFM shows a reduction in surface roughness under the effect of montmorillonite modified, and particularly with (1 phr) of O-MMT.

Dans ce travail, nous avons développé des couches nanométriques biocompatibles à base de titane (TiN et TiO2) sur acier inoxydable 316L, par CAE-PVD (Cathodic Arc Evaporation), qui est un procédé efficace pour la synthèse de revêtements de haute qualité. Nous avons axé notre étude sur une caractérisation mécanique et tribologique des revêtements par des tests d’indentation et des rayures. Les résultats obtenus montrent une morphologie dense et uniforme couplée à des propriétés mécaniques et interfaciales importantes. Les revêtements TiN et TiO2 ont montré une dureté comprise entre 5,9 GPa et 8,23 GPa. La mesure de l’adhérence par des tests de rayure a montré que les deux revêtements ont une qualité d’adhérence légèrement différente. Les couches développées en TiN et TiO2 ont montré des charges de cohésion critiques comprises entre 1,8 N et 3,3 N avec une charge d’adhérence critique de 13,1 N. Les propriétés tribologiques ont été étudiées, en utilisant un test de Scratch multi-passes à charge constante, ce qui a permis de déterminer le coefficient de frottement et le taux d’usure énergétique. Les coefficients de frottement des deux couches étudiées sont du même ordre de grandeur (0,1), mais on peut dire que la résistance au frottement varie d’une couche à l’autre. L’énergie spécifique d’usure était comprise entre 3,09 × 10−5 J/μm3 et 8,36 × 10−5 J/μm3, et elle n’a pas changé après immersion de la couche de TiN pendant 48 h dans une solution de NaCl à 3 %. Le film mince de TiN, connu pour sa biocompatibilité et ses performances biologiques, a montré des propriétés mécaniques et tribologiques qui lui permettent d’être utilisé dans les implants de hanche et de genou.

The natural stone cutting process is carried out by cutting tools called diamond socket (DS) consisting of two parts diamond and matrix. DS performance in rock cutting highly depends on the production cost of the socket, cutting precision, and energy costs. However, DS performance can be demonstrated after the circular saw with DS is connected to the cutting machine and performs the cutting operation. This trial and error method causes negative effects such as time loss, an increase in labor costs, and disruption in production for natural stone processing plants. For this reason, ultrasonic velocity measurement (UVM) processes are performed on DS to predict DS performance. Within the scope of the study, eight groups of boron carbide (B4C)-doped DS are produced. In the one group of these DSs, no-doped is made, and therefore it is considered as a reference socket. The other seven groups are B4C-doped at different rates. Metallographic parameters (MPs) (unit volume weight, porosity, Knoop hardness, weight wear loss) of DSs produced before cutting experiments are determined. Then cutting performance parameters (CPPs) (specific cutting energy, power consumption, specific abrasion) of circular saws prepared with DS groups are obtained by performing cutting experiments on granite samples. After ultrasonic velocity (UV) in diamond sockets is measured experimentally, the correlations between UV and MPs and CPPs are analyzed. As a result of the experimental analyses, it has been determined that there is a significant correlation between these parameters and UV. Based on these correlations, it has been determined that the UVM method can be used both in the quality control of DSs and in the prediction of cutting performance.

Ce travail s’inscrit dans le cadre du recyclage des déchets industriels (sciure de bois). L’élaboration du charbon de bois et la production de la sciure de bois par les scieries en Côte d’Ivoire entraînent des problèmes environnementaux, climatiques et sanitaires. La présente étude propose, une solution palliative à ces problèmes à partir de l’élaboration de charbon dénommé biocharbon, réalisé avec ces déchets. Cependant, le problème prédominant est la pression de compactage optimale pour confectionner les combustibles. Le but de cette étude est de déterminer cette pression de compactage. Les matières premières utilisées sont la sciure de bois de l’Iroko (Chlorophora excelsa) carbonisée et l’amidon de manioc (Manioht exculenta) transformé en empois d’amidon (EA). Pour les agglomérer, quatre formulations de rapport EA/Sb égale à 0,75, 0,87, 1 et 1,125 sont employés avec une pression de compactage variant de 100 à 500 kPa par pas de 100. Les résultats obtenus à partir des essais montrent que les biocharbons élaborés avec la formulation de rapports 0,75 ne sont pas bien consolidés quelque soit la pression de compactage. Ceux de rapport 1,125 ne nécessitent pas de pression de compactage et ceux de rapport 0,87 et 1 se consolident à 500 kPa. Concernant la masse volumique, elle augmente avec la pression de compactage et on observe une perte de matière pour le rapport 1,125 lorsque la pression est supérieure à 300 kPa. Les essais de combustion révèlent la présence d’odeurs et un dégagement de fumée pour les biocharbons de rapport 1,125. Ainsi, pour l’élaboration des biocharbons, les rapports 0,87 et 1 sous une pression de compactage de 500 kPa sont à retenir pour la formulation idéale.

Copper-graphite composite is one of the most important copper based composites, which is used, widely in electrical applications due to its excellent conductivity and high wear resistant. In this work, an attempt has been made to improve the multi-performance characteristics of copper graphite composite prepared by powder metallurgy and increase its expected life by optimizing the manufacturing process of this composite using statistical method. The experiments were carried out under various conditions of compacting pressure, sintering temperature and graphite content based on L9 orthogonal array. The experimental results indicated that multi-performance characteristics of the prepared composite such as electrical conductivity, densification and wear rate are influenced significantly by the studied parameters and the optimal process parameters level for optimum multi-performance characteristics was obtained in a compaction pressure of 750 MPa, sintering temperature of 950 °C and 10 Vol.-% of graphite content.