english ECATERINA ANDRONESCU, MIRCEA BEURAN, DAN CORNELIU JINGA, CLAUDIU STEFAN TURCULET
Rezumat
Evoluția tehnologică și complexitatea abordărilor obligă cercetătorii și practicienii la abordări interdisciplinare. Nanoștiința a deschis pentru știința materialelor domeniul dimensiunilor 1-100 nm unde proprietățile se schimbă semnificativ impunând cercetătorilor reconsiderarea aplicațiilor și evidențierea de noi oportunități. Sinteza și caracterizarea nanoparticulelor au condus spre deschiderea unui domeniu noi de aplicații – nanomedicina. Alegerea unor terapii medicale, adecvate informațiilor obținute direct de la pacient definește medicina personalizată, iar asocierea diagnosticării cu tratamentul propriu zis (abordarea teranostică) și cu integrarea inteligenței artificiale generează medicina moderna țn prezent și în viitor. Articolul reprezintă o primă deschidere a unui subiect provocator care dinamizează evoluția și precizia procedurilor medicale.
Cuvinte cheie
nanoparticule, nanomedicina, abordare teranostică, inteligența artificială
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Anul
2026
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Numărul
56 (2)
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Paginile
143-154
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Domenii de interes
BIOMATERIALE ȘI BIONANOMATERIALE; SUBSTANȚE, PROCEDURI ȘI DISPOZITIVE PENTRU MEDICINĂ
MIHAI EFTIMIE, CARMEN UDREA, ALINA MELINESCU, ANA FILIP
Rezumat
Au fost elaborate sticle borosilicatice prin doparea cu CoO și, respectiv, NiO a unei compoziții de bază, pentru a studia influența acestor ioni asupra proprietăților optice, structurale, termice și chimice. S-au elaborat două compoziții din materii prime de puritate analitică, topite în creuzete de alumină la 1250°C, turnate în matrițe de grafit și recoapte pentru a elimina tensiunile interne. Sticlele au fost caracterizate prin încercări de stabilitate hidrolitică, dilatometrie, spectroscopie UV-Vis, măsurători de vâscozitate și spectroscopie FTIR. Rezultatele arată că atât Co2+, cât și Ni2+ modifică rețeaua vitroasă și comportamentul optic chiar și la concentrații scăzute (0,5 % în greutate). Sticla cu Ni2+ prezintă o stabilitate hidrolitică mai bună și un coeficient de dilatare termică mai mic, în timp ce sticla cu Co2+ are un interval de lucru mai scurt datorită unei variații mai rapide a vâscozității cu temperatura. Spectrele UV-Vis confirmă benzile de absorbție caracteristice ale ionilor Co2+ and Ni2+, care indică o coordinare tetraedrică a Co2+ și o combinație de coordinare tetraedrică și octaedrică distorsionată pentru Ni2+. Analiza FTIR indică rearanjări structurale ale unităților Si-Onepuntat și [BO3]3-/[BO4]5- induse de ionii metalici tranziționali. Studiul demonstrează că adăugarea de CoO și NiO permite modificarea comportamentului la prelucrare al sticlelelor borosilicate, aspect relevant pentru aplicații funcționale.
Cuvinte cheie
sticlă borosilicatică, oxid de cobalt, oxid de nichel, sticlă colorată, proprietăți optice, spectroscopie FTIR
SUDARSONO, PRINOB AKSAR, ABDUL KHOIRI AL-LATIF, MUHAMMAD RIFKY
Rezumat
Geopolymer concrete is an innovative environmentally friendlier material in terms of being a replacement material for Portland cement by using silicate and aluminium materials like fly ash to replace both natural stone and powder aggregates. In this study, we investigate the effect of adding fiberglass fibers to the physical and mechanical properties of fly ash-based geopolymer with porous structures. In terms of geopolymers we use alkali activators (sodium hydroxide NaOH and sodium silicate Na2SiO3) and foaming agent to prepare lightweight concrete. Fly ash is combined with fiberglass fibers in the weight percentages of 0.00, 0.25 and 0.50 The tests, include density, porosity and compressive strength along with microstructural analysis using Scanning Electron Microscope (SEM). The findings indicated an increase in the porosity value from 32.83% to (44.90%) with decreasing density value from 1.1953 to 1.0042 g/cm3 ranging of fiber content addition respectively On the other hand, while porosity was increased its value in compressive strength significantly increased from 3.41 MPa up to 9.29 MPa. Results of microstructural analyzes showed that in the case of the sample devoid of fibers, a loose pore structure was observed, consisting of unevenly distributed and partially unstable pores while addition of fibers led to a more uniform pore system. A more connected pore network was obtained at higher fiber content. The improved mechanical performance was attributed to the reinforcing effect of the additions of fiberglass fibers that increased pore stability, permitted efficient stress distribution and acted as crack intermediary mechanism in the geopolymer matrix. A balance point between mechanical strength and lightweight was reached at 0.25 fiber percentage. This evidence demonstrates that applying fiberglass reinforcement develops high-performance lightweight geopolymer composite materials suitable for structural applications.
Cuvinte cheie
fly ash, foamed geopolymer, fiberglass fiber, compressive strength, porosity, microstructure
LONGHAI YE
Rezumat
Tensile behavior of Two-dimensional carbon fiber reinforced silicon carbide composite （2D-C/SiC） composites was also studied systematically under quasi-static and high strain rate conditions at temperatures of 20, -70, -150 ℃ to the liquid nitrogen temperature ( -196 ℃). Mechanical loading was performed on a universal testing system with low strain rates and a split Hopkinson tensile bar system with dynamic regimes, with strain rates between 10−3 and 300 s−1. In all test conditions, the material showed a clear nonlinear stress-strain behavior before failure, which is indicative of its pseudo-plastic deformation behavior. Cooling and loading rate were both found to enhance strength. Tensile resistance was observed to rise significantly as the environment changed to cryogenic temperatures. An analogous strengthening behavior was noted as strain rate increased, which is rate-dependent mechanical behavior. Fractographic analysis also helped to understand the mechanisms of damage. In the quasi-static loading, strong fiber pull-out characteristics were observed, indicating progressive interfacial debonding before ultimate failure. Conversely, specimens with dynamic loading exhibited significantly shorter pull-out lengths, suggesting a higher interfacial constraint and more sudden fracture mechanisms. At low temperatures, fracture surfaces appeared irregular and rugged. Instead of massive bundle extraction, localized fiber cluster pull-out with comparatively smooth fracture traces on the extracted clusters dominated failure.
Cuvinte cheie
2D-C/SiC, composite material, low temperature, dynamic tensile
XIAOFENG CHEN, QIAN HONG, LIHUA DING, YANBING WANG, XIAOXIAO MA, XIAOHU SUN, JINGJING ZHOU, JIA HU, XIN LUO
Rezumat
The traditional ordinary Portland cement has a relatively high pH value, which is often extremely unfavorable for vegetation restoration when slope protection treatment is carried out. For this purpose, in this study, ammonium dihydrogen phosphate (ADP) is selected to excite steel slag (SS) to generate cementitious materials with a lower pH value, which are used to bond recycled aggregates, and a porous ecological concrete with a low pH value and environmental friendliness is prepared. The results show that when the SS/ADP is 6 and the water-cement ratio is 0.22, the compressive strength of the prepared cementitious material reaches 37.7 MPa. When it is compounded with aggregates with particle sizes ranging from 12 to 18mm and the slurry-bone ratio is 1/5, the porosity of the prepared porous ecological concrete reaches 35.4%, and the compressive strength reaches a maximum of 4.3 MPa. In addition, it has been confirmed that ADP can significantly reduce the harmful metal ions retained in steel slag, making the content of harmful metal ions in ecological concrete more obviously lower than the national standard limit.
Cuvinte cheie
acid activation, recycled aggregate, ecological concrete, mechanical properties, mechanism research
WENWEN QI
Rezumat
Flexible conductive polymer films require stable charge transport under large deformation, repeated motion, and sweat-related interfacial disturbance. This study develops a polythiophene-based conjugated polymer/multi-walled carbon nanotube composite film using gradient drop-casting, zeta-potential-guided dispersion control, and electric-field-assisted network biasing. The strategy aims to separate a mechanically compliant domain from a current-carrying backbone, thereby reducing conductive-network fracture and signal drift during dynamic strain. The optimized film shows a carbon nanotube orientation degree of 0.82, crystallinity of 46.5%, surface roughness of 18.7 nm, and filler-distribution deviation of 3.1%. Conductive-cluster connectivity remains above 0.85 within the 0–80% strain range, while impedance drift is only 1.2% after 2 × 105 loading cycles. Under simulated sweat with conductivity of 9.7 mS cm-1, conductivity drift is limited to 0.8%. These results indicate that the proposed network-locking strategy improves electromechanical stability and provides a reliable material platform for human-machine interaction and sports health monitoring
Cuvinte cheie
flexible conductive polymer films, dynamic percolation network, multi-walled carbon nanotubes, solvent-induced self-assembly, electric-field biasing, strain sensing, human-machine interaction
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Anul
2026
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Numărul
56 (2)
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Paginile
188-195
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Domenii de interes
BIOMATERIALE ȘI BIONANOMATERIALE; SUBSTANȚE, PROCEDURI ȘI DISPOZITIVE PENTRU MEDICINĂ
MOHAMED BACHAR, DJILLALI CHACHI, REBIH ZAITRI
Rezumat
In this study, we have examined the influence of straight-strand fibre reinforcement on the post-cracking mechanical behaviour of natural aggregate concrete (NAC) and recycled aggregate concrete in which 50 % of the natural coarse aggregate has been replaced by recycled aggregate (RAC50). The parameters studied experimentally have included compressive strength, compressive toughness and dynamic impact energy.The results revealed a significant increase in energy dissipation compared with the reference concrete (0 % fibres), throughout the range of fibre volume fractions (0 %–2 %) and aspect ratios (h/d=60, 80,100). A more significant rate of change in both modes of energy dissipation was observed for fibre-reinforced concrete with recycled aggregates (RAC50-SF) than for fibre-reinforced concrete with natural aggregates (NAC-SF). At a dosage of 1.5 % and an aspect ratio of (h/d=100), both types of concrete, (RAC50-SF) and (NAC-SF), exhibit similar values for both energy modes, thus making recycled concrete suitable for use in high-performance structures.
Cuvinte cheie
compressive strength, recycled aggregate concrete, compressive toughness, dynamic impact energy, fiber-reinforced concrete
LEILA BAZIZ, NADJET BENCHIHEUB, ABDELAZIZ SID, ISMAHANE SERRADJ
Rezumat
This investigation is devoted to study the particular impact of laser Nd:yag radiation on certain mechanical properties such that: elastic modulus, hardness and stiffness of two types of Al-Si-Cu-Mg alloys (industial and recycled) through nanoindentation measures. These materials were subjected to a Laser treatment Nd: Yag with wavelength λ=1.064nm, for different pulse counts. The Atomic Force Microscope (AFM) is used to visualize and analyze radiated regions at the nanoscale, as well as to conduct nanoindentation tests for assessing hardness, stiffness and elastic modulus. In this context, the present study demonstrates that both elasticity and hardness of the radiated areas increase with the number of laser shots. Following a specific number of shots (40 shots for industrial aluminum and 60 shots for the recycled one); all radiated zones display analogous nanoindentation profile. Due to the changes induced to a nanostructural refinement shown by the (SEM); further a significant improvement in mechanical properties is achieved .However, increasing the number of shots to high levels (about 160 shots for industrial aluminum and 200 shots for recycled aluminum) cause a homogenate material structure, resulting an improvement in mechanic properties.
Cuvinte cheie
recycled aluminum alloys, industrial aluminum alloy, Nd:Yag laser, nanoindentation, elasticity and hardness
OANA CAMELIA IACOB
Rezumat
Lucrarea de fata prezintă o analiză a modelelor de sustenabilitate eco-economică în statele membre ale Uniunii Europene (UE) pentru anul 2024, utilizând tehnici avansate de extragere a datelor. Obiectivul principal este de a investiga măsura în care indicatorii economiei circulare și structura impozitării mediului sunt influențate de performanța industrială și de mediu a fiecărei țări. Cercetarea este structurată în jurul a două direcții complementare. Prima direcție utilizează un algoritm de învățare nesupervizată pentru a grupa economiile europene în funcție de capacitatea lor de a integra materiale circulare în industrie. În același timp, identifică și taxele de mediu și fluxurile comerciale de materii prime reciclabile care caracterizează clusterele cu cea mai mare eficiență a resurselor. A doua direcție utilizează un algoritm de clasificare supervizată pentru a identifica pragurile economice critice (taxe pe poluare, taxe pe energie și fluxuri de investiții străine directe) care determină succesul unei țări în atingerea unei rate ridicate de utilizare a materialelor circulare în producție, prin transformarea acestei rate în clase nominale și extragerea unor reguli de decizie logice. Prin încorporarea unor indicatori suplimentari, cum ar fi gestionarea deșeurilor, dependența de importuri și investițiile străine directe, studiul oferă o perspectivă cantitativă asupra modului în care politicile fiscale de mediu și fluxurile de materiale condiționează tranziția către o economie circulară în UE.
Cuvinte cheie
sustenabilitate, taxare de mediu, economie circulară, analiză de tip data mining