In this experimental study, six lime-based mortar compositions were prepared under laboratory conditions, with sand-to-lime putty volume ratios of 1, 2, 3, 4, 5, and 7. The specimens were subjected to accelerated carbonation and subsequently tested. Compressive strength tests on standard samples revealed values significantly higher than those specified in the current Romanian design and assessment regulations for the same composition. Tests performed on non-standard specimens, with reduced height - close to that corresponding to the thickness of the mortar joint - yield very high measured values, making it difficult to establish correlations between these and the strengths obtained on standardized specimens. Chemical analysis proved to be a feasible method for evaluating mortar strength, provided that the aggregate does not contain calcium carbonates. The surface hardness method does not seem appropriate for lime mortars, as the recorded values are too low. For the penetration resistance tests and fastener pull-out tests, the measured values are very scattered, so these methods do not seem reliable for low strength mortars. The Double Punch Test (DPT) appears to be a promising alternative for the determination of compressive strength on site, with experimental results showing a strong correlation with standard compressive strength values. However, tests using multiple methods on samples taken in situ are needed to estimate differences due to curing conditions, starting from chemical analysis that can provide compositional characteristics.
This study evaluates the hydrophobic properties of silica nanoparticle-polydimethylsiloxane (Si-PDMS) treatment developed for fired-clay masonry structures and infrastructures exposed to moisture. The work emerged from a conservation-driven question that also applies to contemporary construction: how to reduce liquid-water penetration without turning a porous substrate into a sealed, vapour-impermeable system with out damaging the material or its apperance. The formulation strategy follows a biomimetic route in which silica nanoparticles generate near-surface roughness and PDMS lowers surface energy, translating lotus-inspired surface. Historical and factory-made firedclay bricks were dryed to constant mass and treated by brush application. The dispersion was prepared without solvent, homogenized by mechanical agitation at 50 Hz, and visually remained free of sedimentation or agglomeration during the preparation/application window. Wettability was assessed by static contact angle, bulk liquid uptake by 24 h immersion, and capillary transport; lateral faces were sealed during the capillary test. The treatment shifted the surface from highly hydrophilic (11.0 degrees) to hydrophobic/superhydrophobic behavior (105.4- 114.7 degrees), reduced 24 h water absorption from 6.70% to 5.56-5.97%, and lowered the capillarity coefficient from 0.0015446 to 0.0013109-0.0013657 g/cm(2)& centerdot;s. The highest surface beading was obtained at 2% Si-PDMS mixture, whereas the lowest immersion and capillary uptake occurred at 1% Si-PDMS mixture, indicating a non-linear tradeoff between interfacial wetting control and bulk transport. Water-vapour transmission and standardized durability tests were not part of the present article; therefore, compatibility claims remain limited to the wetting and hygric indicators reported here.
Recent studies extensively researched the release of titanium particles and ions from dental implants. Titanium release is recognized as a complex process influenced by mechanical, chemical, and biological factors. It plays a significant role in the peri-implant tissue adaptation and the long-term stability of implants. This study aimed to assess titanium release in the peri-implant mucosa and to subsequently correlate these findings with the biomechanical behaviour of implants. An integrated methodology was applied to achieve this, combining exfoliative cytology, inductively coupled plasma mass spectrometry (ICP-MS), and finite element analysis (FEA). The ICP-MS findings revealed detectable concentrations of titanium in peri-implant cells, ranging from approximately 47 to 85 ppb, following a triphasic temporal pattern based on implant age. FEA findings indicated a progressive alteration of stress distribution based on the corrosion level, shifting from a uniform and balanced mechanical behaviour to a more localized and imbalanced stress pattern. Overall, the combined use of exfoliative cytology, ICP-MS, and FEA offers a comprehensive framework for the early assessment of biological and biomechanical risks, with possible applications in implant therapy customization and optimization of long-term monitoring strategies.
Investigation of an 120 years old reinforced concrete beam were carried out in order to find the degree of degradation and other durability characteristics. The idea behind the investigations was to find compositional parameters to ensure durability based on a real-scale experiment. Half Cell Test and visual observations show good condition of the reinforcing bars despite the age of beam. Carbonation depth in some places is practically zero and further investigation presented a high pH in the concrete. Using XRD on powder from the concrete matrix we found unhydrated calcium silicates even after mare than 100 years, fact which attributed to the coarse grinding of a belite cement. This led to self-healing concrete long before the concept appeared.
The possibility of using other types of cements, besides the unitary ones provided for by the road concrete standards, was studied. In this regard, the changes in mechanical and durability properties when replacing a CEM I42.5R cement with CEM II A-M (S-LL) 42.5R type cements and one made in the laboratory of type CEM II A-V were analyzed. Concretes made with cements with supplementary cementitious materials SCM presented better mechanical characteristics in terms of compressive strength, bending strength and wear resistance at long terms or equivalent to concrete made with unitary cement for the modulus of elasticity. Durability tests - freeze-thaw resistance highlighted a better behavior of concretes with cements with SCM compared to the standard one. The shrinkage of concrete with CEM II A-V type cement was very close to that of the reference concrete made with unitary cement; concrete made with CEM II A-M (S-LL) cement had a significantly higher shrinkage. The results are promising, opening the way to testing on a larger scale several types of cements with additives, both for classical mechanical and durability properties but also for some results from the study of specialized literature from other countries.
This paper investigates the effect of combined calcium nitrate tetrahydrate (CN), calcium formate (CF), and silica fume (SF) on early-age compressive strength in Portland cement mortar. For an appropriate mix design with limited numbers of trials, a Taguchi experimental design was conducted. CF was added at 0.5%, 1%, and 1.5%, CN at 1%, 2%, and 3%, and SF at 5%, 10%, and 15% as partial cement replacements. Compressive strength measurements, XRD, FT IR, and FESEM provided information on hydration products, phase transformations, and microstructural densification upon hydration. The optimum mix of 1% CN, 1% CF, and 5% SF improved the 7-day compressive strength by 16.1% over that of the control. CF favored the development of C-S-H by formate action; CN accelerated hydration through the provision of calcium ions, and SF reduced porosity by pozzolanic reaction and filler action. XRD and FT IR showed a decrease in portlandite, while FESEM presented a denser matrix. Accordingly, the results suggest a feasible way to enhance the early performance of cement mortars by adjusting CN, CF, and SF contents.
Mercury intrusion porosimetry (MIP) within the present study, was not used as a stand-alone proof of pore blocking, but as a complementary microstructural method interpreted in relation to capillarity and surface-level hydrophobic behaviour of the hydrophobised brick specimens, with the aim of contextualising changes in liquid water transport after PDMS-Si biomimetic treatment. The study evaluated a silica nanoparticle-polydimethylsiloxane (Si-PDMS) mixture. Aplication to historical Gothic-type and factory-made fired-clay foundation bricks was made by brush and the homogenization was performed by mechanical agitation at 50 Hz, and no visible sedimentation is observed, phase separation of the materials used or agglomeration was during the preparation and application window. The treatment was applied by brush on the exposed surfaces of the specimens. This methodological position is essential because MIP primarily reflects the smallest accessible constrictions within the pore network and is influenced by ink-bottle effects for the surface pore distribution. The results showed that historic bricks that where tested exhibited higher open porosity and a broader pore-throat distribution than modern bricks, confirming their greater susceptibility to capillary uptake and their higher capacity for treatment penetration. By contrast, denser modern bricks that where tested presented lower baseline porosity and more limited changes after treatment. MIP outputs indicated that the 2% Si mixture produced the clearest refinement of accessible porosity, reducing total porosity from 42.842% to 35.111% for Gothic bricks and from 28.861% to 25.236% for factory-made bricks. In contrast, the 5% Si mixture showed a partial rebound in porosity-related parameters, suggesting diminishing returns at higher solids loading. MIP served as a contextual and plausibility-based tool, helping to explain why reductions in capillary vulnerability were more pronounced in more porous historic materials without implying that hydrophobisation acted by sealing the substrate. The porosity analysis therefore supports the conclusion that the biomimetic PDMS-Si treatment modifies interfacial wetting and partially alters accessible near-surface transport pathways, with implications for reducing liquid water ingress, salt crystallization risk, and freeze-thaw susceptibility. The study explicitly acknowledges its current experimental limitations. Because not all the dimensions of the potential study were addressed water-vapour transmission was not measured, and no standardized durability campaign was completed. We attempted to test freeze-thaw behaviour the results wer inconclusive because it was not performed according to a standardized method and the specimens were damaged during the analysis stage. Mechanical strength remain essential for complete cross-study comparison. Interpreted within these methodological boundaries, MIP provides a credible microstructural framework for understanding the protective action Si-PDMS treatment in conservation-oriented masonry applications.
The Prahova Subcarpathians stretch between the D & acirc;mbovita Valley and the Teleajen Valley, representing a large Subcarpathian relief unit, part of the Curvature Subcarpathians. This area consists of a series of massifs and hilly ridges, with elevations ranging between 300 and 850 meters, alternating with Subcarpathian depressions. This intermediate region between the mountains and the plains is characterized by its geographical complexity and the intensity of the urbanization process. The relationships between the relief and settlements are particularly prominent in the local geographical landscape. They can be observed at the level of major landforms, as well as larger or smaller sculptural forms, but mainly at the level of valleys and interfluves. The exposure of Subcarpathian settlements to various types and degrees of geomorphological (and hydrological) risk is a consequence of the specific way these relationships were formed, including valley settlements (terraces, alluvial cones, and glacis slopes) and interfluve settlements. All these aspects contribute to the originality and variety of the Prahova Subcarpathians, connecting the relief with its morphographic and morphometric characteristics, human settlements, economic activities and land use, all of which are in a relationship of interdependence and mutual conditioning.
This article examines a new research direction to enhance the performance of polypropylene meshes commonly used in hernia repair by incorporating iron oxide nanoparticles (IONPs). Classical polypropylene meshes are mechanically strong, but they have been associated with postoperative infections when contamination occurs [1]. In this article, we review the possible integration of IONPs into polypropylene meshes to improve antimicrobial properties, tissue integration , and reduce inflammation [1,2]. IONPs are known for their magnetic and antibacterial properties, especially when functionalized with biocompatible coatings such as chitosan or polyethylene glycol (PEG) [3,4]. These coatings can minimize the risk of post-surgical complications with better tissue integration and reduced biofilm formation [5,6]. The potential for magnetic guidance in tissue regeneration and MRI visibility makes IONPs a valuable tool for non-invasive monitoring and post-operative treatments, including magnetic hyperthermia for infection control [2,7]. This concept raises concerns about production scalability and regulatory compliance. Despite these technological advancements, transitioning such concepts from the laboratory to clinical practice faces technical complexities of industrial-scale production, uncertainties regarding nanotoxicity, and the demands of regulatory frameworks [3,8]. This review brings into discussion the need for further studies to validate long-term biological safety and the economic sustainability and clinical feasibility of IONP-treated polypropylene meshes. These studies could help define the role of such composite materials as next-generation solutions in the surgical management of hernias and in addressing the potential toxicity of nanomaterials [3,8].
This study compared the mechanical behavior and chemical evolution of three temporary dental cements-zinc phosphate (FOZ), glass ionomer (CIS), and resin-based (DT)-aged in air and artificial saliva, and explored how microstructural changes relate to their mechanical performance. Cylindrical specimens of FOZ, CIS, and DT were prepared according to manufacturers' instructions and aged for 3, 14, and 28 days in air or artificial saliva at 25 degrees C. Compressive strength and elastic response were measured by uniaxial testing. X-ray diffraction (XRD) and Fouriertransform infrared spectroscopy (FTIR) were used to characterize crystalline phases and functional groups. FOZ showed marked phase evolution, with XRD revealing a shift from a mixed ZnO-Hopeite composition toward ZnO dominance in air, while saliva preserved higher Hopeite content; these changes were associated with reduced compressive strength in air and increased strength in saliva. CIS remained crystallographically and chemically stable, with BaSO4 as the main crystalline phase and minimal FTIR changes, matching its nearly unchanged compressive strength in air. DT maintained a broadly constant biphasic calcium phosphate-zirconia pattern and a stable resin FTIR signature, consistent with its predominantly elastic behavior and modest variation in elastic force, especially in saliva. The three cements exhibit distinct, material-dependent aging patterns that directly influence their mechanical performance under simulated oral conditions.
Conventional nanoparticle synthesis routes raise growing environmental concerns, making green approaches increasingly relevant. Here, NiO nanoparticles were prepared via hydrothermal synthesis, using Ziziphus lotus (L.) almond as a natural mediating agent, alongside a control synthesis without extract. According to our investigations, no previous study has used, the almonds of Ziziphus lotus (L.), for the production of metal oxide nanoparticles. The nanoparticles obtained were characterized by X-ray diffraction (XRD), UV-visible spectroscopy, scanning electron microscopy (SEM), UV-visible spectroscopy, and zeta potential measurement. The results we obtained showed that the hydrothermal temperature is a crucial parameter in crystallization: samples treated at 140 degrees C exhibited good crystallization, with crystallites averaging around 34 nm in size, and SEM images revealed a clearly ordered lamellar morphology. The presence of this almond extract had multiple effects on the resulting nanoparticles. Their growth was directed towards anisotropic morphologies, their surface charge was modified, and their optical band gap was considerably widened, reaching 3.75 eV, compared to 3.48 eV in the sample without the extract. The results of this study confirm that hydrothermal biosynthesis is a easy and environmentally friendly method for producing NiO nanoparticles. Thus, these nanoparticles may provide new opportunities in the domain of optoelectronics, energy storage and biomedical applications.
Gaining basic knowledge on the nanostructure of advanced composites, based on curcumin, CCM, mixed with various bioactive compounds, in polyethylene glycol, PEG6000, will allow better innovative applications of these composites for their importance, particularly as functional foods and supplements for human health care benefits. Our goal is to understand the behavior of curcumin, in the presence of whey protein concentrate, WPC, transresveratrol, RES, or silymarin, SIL, within PEG6000 matrix, and the role of biomolecules in making advanced composites, such as PEG6000-CCM, PEG6000-CCM-WPC, PEG6000-CCM-RES-WPC and PEG6000-CCM-SIL-WPC, and thus, developing tailored compositions with multifunctionality. In this study, AFM images: 2D-and 3D-topographies as well as phase and amplitude images provide the surface morphology of nanostructured composites at nanometer resolution and surface roughness as root mean square, RMS, confirming the miscibility of compounds within PEG6000 matrix, and the shape and size of composite nanoparticles. The WPC enhances the stability of these composites through the intermolecular hydrogen bonds with CCM and RES or SIL, leading from small molecules to advanced composite nanostructures within the PEG6000 matrix, as evidenced by AFM investigation. FTIR data for all four composites reveal the interaction between the precursor components within PEG6000 matrix primarily by the formation of new intermolecular hydrogen bonds between their functional groups. Conclusively, the innovative nanocomposites, PEG6000-CCM, PEG6000-CCM-WPC, PEG6000-CCM-RES-WPC and PEG6000-CCM-SIL-WPC, provide an effective strategy for the design of novel promising nanocomposites for biomedical applications, such as drug delivery systems to treat various diseases, especially cancer and for bone regeneration medicine.
The presented research work explores the fabrication and parametric optimization of beta-Tri-Calcium Phosphate (beta-TCP) composites reinforced with Zinc Oxide (ZnO) powder, which make them suitable for biomedical applications. TCP is widely recognized for its biocompatibility and bioresorbability, while ZnO offers strong bacterial inhibition and enhanced mechanical strength. The composite is fabricated using a compaction-sintering process, known as Powder Metallurgy technique followed by investigation of physical and mechanical attributes of the as-formed composite specimens. The process parameters viz., particle size of the constituents, volumetric percentage of TCP content and sintering temperature are optimized and the best possible specimen is selected among various combinations using a combinatorial statistical technique namely Historical Data incorporated Additive Ratio Assessment (HD-ARAS). The results demonstrate the performance of beta-TCP-ZnO composites with significant enhancement in Particle Density, Microhardness and Compressive Strength. The starting particles and best ranked composite specimen is further subjected to microstructure study using Scanning Electron Microscope (SEM) to validate the results. This research supports the potential candidature of TCP-ZnO composites as viable materials in bone repair and regeneration.
The aim of this research was to obtain composite ceramic materials based on a silicon carbide (SiC) matrix modified with sintering additives (Al2O3 and Y2O3) and reinforced with 1 wt.% or 5 wt.% milled carbon fibers (C-f) using the spark plasma sintering (SPS) technique. SPS processing was carried out under vacuum at an applied axial pressure of 50 MPa and a sintering temperature of 1850 degrees C, with a holding time of 10 minutes. The structural and morphological characteristics of the silicon carbide-based composites were examined using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Physical and mechanical properties, including bulk density, apparent porosity, Vickers hardness, elastic modulus, friction coefficient, and specific wear rate, were evaluated for all sintered specimens. XRD analysis indicated the predominance of the beta-SiC phase in the composite materials. The results showed that all samples sintered at 1850 degrees C achieved bulk densities above 3 g/cm(3) and apparent porosities below 1.72%, corresponding to a densification degree of at least 98.28%. Furthermore, all analysed specimens exhibited Vickers hardness values exceeding 1568 HV, modulus of elasticity in the range of 240-299 GPa, and an average friction coefficient between 0.41 and 0.93 in dry sliding conditions.
This work presents an optoelectronic study of cobalt-doped nano-TiO2 camouflage films prepared via a non-hydrolytic sol-gel route and examines theirsuitability fordevice integration. Photoluminescence (PL) and UV-Vis absorption measurements show that the films possess a tunable bandgap (3.12-3.24 eV) and exhibit a rapid photoconductive response under visible illumination, with a rise time of about 15 ms and a decay time of roughly 25 ms. SEM observations indicate a highly uniform film morphology, and UV aging tests verify that the coatings retain their structural and optical stability in ambient conditions. When these materials are incorporated into prototype thin-film photodetectors, the devices achieve an on/off photocurrent ratio exceeding 10(3 )and a responsivity of 0.15 A/W at 450 nm, pointing to their practical promise for adaptive optical filters and smart window coatings. In addition, assessment of visual performance shows that nanoscale optical camouflage layers deliver an average increase of 0.91 points in visual impact over conventional materials, underscoring the capacity of nanoscale optical and electronic architectures to reshape graphic design by enabling more dynamic and aesthetically compelling visual experiences.
The paper explores the domain of digitally fabricated dental prostheses, specifically detailing the application of CAD/CAM (Computer-Aided Design/Computer-Aided Manufacturing) methodologies within the field of restorative dentistry. The research undertakes a thorough examination of the digital fabrication sequence in prosthodontics, which encompasses critical phases such as intraoral/laboratory scanning, CAD modeling, automated milling, and final surface treatment. A significant portion of the work is dedicated to the CEREC system's implementation in the chairside clinical environment (i.e., procedures completed within the dental practice). Furthermore, the study includes an assessment of the specialized equipment and the mechanical behavior of three notable restorative biomaterials: Zirconium Dioxide, IPS e.max Ceram Dentin, and Cerasmart. The CEREC system is a computerized system that can be used to design and produce, in a single session, highly accurate, aesthetic, and durable ceramic restorations for small cavities. The dental materials were analyzed both before and after the firing process using infrared absorption spectroscopy (FITR), and the morphology of the samples was highlighted using a high-resolution scanning electron microscope equipped with an EDX detector and thermal analysis (TG-DTG-DTA). The characterization methods were applied to compare the performance of the three materials, with a focus on marginal adaptation, aesthetics, strength, and ease of processing, and to highlight the essential differences between the materials in the context of their use in dental restorations. The results of this study, together with data from the literature, help to understand the interaction of these materials with tissues and also to modify the properties of these materials.
Utilization of agricultural waste for construction materials is an emerging pathway for sustainable development. This study examines the valorization of the Washingtonia filifera palm fibers, one of the main agricultural by-products in Algeria, as a reinforcing material for concrete. Various concentrations and optimum conditions of sodium hydroxide (NaOH) solutions were used to extract the fibers, and subsequently tensile characterization was carried out. The fiber undergone at 2% NaOH for 96 hours has been found to have a 225.95 MPa tensile strength and a 7.85 GPa Young's modulus. Concrete mixtures were made with 0.5%, 1%, and 1.75% palm fibers by weight of cement. According to mechanical testing, the incorporation of fibers resulted in a slight loss of early age compressive strength, mainly due to porosity. However, as the curing age progressed, the strength performance gradually recovered. The compressive strength of 1.75% fiber blend at 28 days was a maximum of 26.79 MPa. Similarly, flexural tensile strength was notably increased as it achieved a value of 5.96 MPa which was nearly 22% higher than the control. The results show that palm fibers can be converted to effective and green reinforcements when treated appropriately, offering benefits to both engineering applications and the environment.
A novel nanoscale optoelectronic imaging platform is presented that leverages quantum-dot-sensitized sensors together with a hybrid clustering strategy to realize ultra-high-speed acquisition and analysis of rapid nanoscale phenomena. By embedding CdSe/ZnS quantum dots into a plasmonic imaging circuit and feeding the sensor output into a modified k-means routine steered by an artificial fish swarm algorithm (AFSA), data redundancy is suppressed and representative keyframes are extracted in real time. Experiments tracking plasmonic nanoparticle motion under pulsed excitation show a 9.96 % rise in clustering accuracy and a 7.44 % increase in recall relative to standard k-means, accompanied by a 0.086 improvement in the silhouette coefficient. Collectively, these results demonstrate concurrent gains in spatial resolution (down to 50 nm) and temporal resolution (sub-microsecond). Demonstrations in in-situ nanomanufacturing quality monitoring and single-molecule bioimaging further illustrate the platform's applicability across nanoelectronics and optoelectronic systems.
Friction welding is an efficient and economical process of joining two similar or dissimilar metals among various welding processes. Now-a-days, the automobile and other industries are using dissimilar metals in a same working area to compensate the problems faced due to temperature and working atmosphere to enhance company's economy. The material AA6351 and EN353 alloy steel have wide applications in aerospace & automobile industries, are joined with different input parameters like Heating Time (HT), Heating ordered using L27 Taguchi Orthogonal Array (OA) to experiment the process. Friction welding is done in KUKA friction welding machine. After experimentation, the responses like temperature, hardness and axial shortening are measured. Using these responses, the optimization is carried out through Grey Relational Analysis (GRA) and the rankings are identified and tabulated to obtain the optimal solutions. Based on rankings, the optimal input parameters are concluded as 18 bar of Heating Pressure (HP), 7 sec of Heating Time (HT), 22 bar of Upset Pressure (UP) and 3 sec of Upset Time (UT). The Field Emission Scanning Electron Microscope (FESEM) analysis is also used to study the Inter-metallic compounds (IMCs).
Making high-performance hybrid composites from discarded fishnets may improve sustainability. Hand-lay-up is used to blend glass fibre and epoxy resin in the study. ASTM standards were followed to quantify tensile, flexural, and impact force. Multiple acid solutions Hydrochloric Acid (HCL), Sulphuric Acid (H2SO4), Acetic Acid (CH3COOH) applied to nylon fishnets destroyed pollutants and strengthened composite assemblies based on Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS) analysis results. Treated consequences demonstrated superior material properties because tensile strengths achieved 50.71 MPa and flexural strengths measured 40.5 MPa while possessing strong impact resistance. A distribution of materials across the hybrid composites along with minimal voids and improved durability made these composites suitable for marine applications which include boat hulls and structural components. Water absorption tests proved excellent resistance capabilities because the composites exhibited low levels of moisture absorption thus maintaining stability when immersed in water. This research dual-purpose project tackles marine pollution and promotes a circular economy via sustainable development by integrating recycled materials into sophisticated composite systems. Chemically modified waste polymers in ecologically friendly engineering applications may improve engineering materials and performance.
