This study comprehensively examines masonry structural diagnostics and analyzes the comparative performance of traditional and advanced strengthening techniques for masonry walls, arches, vaults, and columns. Machine learning and deep learning algorithms are examined in the context of automatically identifying cracks in unreinforced masonry (URM) walls, with a presentation of several research findings. Furthermore, the kinematic and static principles of Limit Analysis, employing a rigid no-tension model, are elaborated upon. The manuscript offers a pragmatic approach, including a comprehensive collection of recent research papers in this field; this paper is therefore valuable for researchers and practitioners specializing in masonry engineering.
Plate and shell structures, within the realm of engineering acoustics, often serve as pathways for the transmission of vibrations and structure-borne noises, facilitated by the propagation of elastic flexural waves. Phononic metamaterials, characterized by a frequency band gap, effectively block elastic waves within certain frequency ranges, but often require a painstakingly slow, iterative approach to design, relying on repeated trials. Deep neural networks (DNNs) have exhibited proficiency in tackling various inverse problems in recent years. A phononic plate metamaterial design workflow is developed and described in this study, using a deep-learning approach. Forward calculations were swiftly accomplished through the application of the Mindlin plate formulation; correspondingly, the neural network was trained for inverse design. Our neural network attained a 2% error in the prediction of the target band gap, using just 360 sets of training and testing data and by strategically optimizing five design parameters. Around 3 kHz, the designed metamaterial plate exhibited -1 dB/mm omnidirectional attenuation, impacting flexural waves.
A film composed of hybrid montmorillonite (MMT) and reduced graphene oxide (rGO) was created and employed as a non-invasive sensor to monitor the absorption and desorption of water within both pristine and consolidated tuff stones. By employing a casting process on a water dispersion containing graphene oxide (GO), montmorillonite, and ascorbic acid, this film was obtained. The GO was then reduced through thermo-chemical means, and the ascorbic acid was subsequently removed by washing. Linearly varying with relative humidity, the hybrid film's electrical surface conductivity demonstrated a range of 23 x 10⁻³ Siemens under arid conditions and reached 50 x 10⁻³ Siemens at a relative humidity of 100%. A high amorphous polyvinyl alcohol (HAVOH) adhesive was employed for sensor application onto tuff stone specimens, thereby ensuring favorable water diffusion from the stone into the film, and this was assessed using capillary water absorption and drying tests. The sensor's performance reveals its capacity to track shifts in stone moisture content, offering potential applications for assessing water uptake and release characteristics of porous materials in both laboratory and field settings.
In this review, the application of polyhedral oligomeric silsesquioxanes (POSS) across a range of structures in the synthesis of polyolefins and the modification of their properties is discussed. This paper examines (1) their incorporation into organometallic catalytic systems for olefin polymerization, (2) their use as comonomers in ethylene copolymerization, and (3) their role as fillers in polyolefin composites. Alongside this, studies examining the utilization of new silicon-based compounds, specifically siloxane-silsesquioxane resins, as fillers for composites comprised of polyolefins are presented. This paper is dedicated to Professor Bogdan Marciniec, in celebration of his jubilee.
A growing supply of materials for additive manufacturing (AM) significantly increases their range of use cases in diverse applications. In conventional manufacturing, 20MnCr5 steel is a prominent example, exhibiting excellent processability in the context of additive manufacturing processes. The process parameter selection and torsional strength analysis of AM cellular structures are incorporated into this research. Brensocatib mouse The research's conclusions indicated a substantial propensity for inter-laminar cracking, a characteristic directly contingent upon the material's layered structure. Brensocatib mouse Moreover, specimens exhibiting a honeycomb structure demonstrated the greatest torsional resistance. To evaluate the optimal characteristics found within samples with cellular structures, a torque-to-mass coefficient was introduced. The honeycomb structure's characteristics were indicative of superior performance, with a 10% lower torque-to-mass coefficient compared to solid structures (PM samples).
Dry-processed rubberized asphalt blends have recently attracted significant attention, positioning them as an attractive alternative to traditional asphalt mixtures. Dry-processing rubberized asphalt has yielded an upgrade in the overall performance characteristics of the pavement, surpassing those of conventional asphalt roads. The objective of this research is to rebuild rubberized asphalt pavement and assess the performance of dry-processed rubberized asphalt mixes based on experimental data obtained from laboratory and field testing. The efficacy of dry-processed rubberized asphalt for noise reduction was tested at various field construction sites. Employing mechanistic-empirical pavement design, a forecast of pavement distress and long-term performance was also executed. Using MTS equipment for experimental evaluation, the dynamic modulus was calculated. Indirect tensile strength (IDT) testing, measuring fracture energy, was utilized to evaluate low-temperature crack resistance. Asphalt aging was assessed employing both rolling thin-film oven (RTFO) and pressure aging vessel (PAV) testing procedures. Employing a dynamic shear rheometer (DSR), the rheological properties of asphalt were evaluated. In the test, the dry-processed rubberized asphalt mixture demonstrated superior cracking resistance. Compared to conventional hot mix asphalt (HMA), the fracture energy improvement was 29-50%. The high-temperature anti-rutting performance of the rubberized pavement was also strengthened. A 19% rise was observed in the dynamic modulus. The rubberized asphalt pavement, as revealed by the noise test, demonstrably decreased noise levels by 2-3 decibels across a range of vehicle speeds. The mechanistic-empirical (M-E) design analysis of predicted distress in rubberized asphalt pavements exhibited a reduction in International Roughness Index (IRI), rutting, and bottom-up fatigue cracking, as shown by the comparison of the predicted outcomes. From the analysis, the dry-processed rubber-modified asphalt pavement shows better pavement performance in comparison to conventional asphalt pavement.
To capitalize on the superior energy absorption and crashworthiness properties of both thin-walled tubes and lattice structures, a novel hybrid structure composed of lattice-reinforced thin-walled tubes with variable cross-sectional cell numbers and gradient densities was designed. This design yielded a high-crashworthiness absorber capable of adjusting energy absorption. To elucidate the interaction mechanism between lattice packing and metal shell, a comprehensive experimental and finite element analysis was conducted on the impact resistance of hybrid tubes, composed of uniform and gradient densities, with diverse lattice configurations, subjected to axial compression. This revealed a remarkable 4340% increase in energy absorption compared to the sum of the individual components. The study investigated the relationship between the configuration of transverse cells and gradient profiles within a hybrid structure and its impact resistance. Results indicated that the hybrid structure possessed a superior energy absorption capacity compared to a bare tube, specifically achieving an 8302% increase in the best-case specific energy absorption. Additionally, the transverse cell configuration was determined to have a more significant effect on the specific energy absorption of the uniformly dense hybrid structure, with a maximum enhancement of 4821% in the various configurations evaluated. The configuration of gradient density exerted a substantial influence on the maximum crushing force exhibited by the gradient structure. Brensocatib mouse Quantitative analysis was applied to study how wall thickness, density, and gradient configuration influence energy absorption. This study, using a combined experimental and numerical simulation methodology, presents a unique idea for enhancing the impact resistance of lattice-structure-filled thin-walled square tube hybrid structures under compressive stresses.
Utilizing the digital light processing (DLP) method, this study effectively demonstrates the 3D printing of dental resin-based composites (DRCs) reinforced with ceramic particles. The printed composites' oral rinsing stability and mechanical characteristics were measured and analyzed. For restorative and prosthetic dental applications, DRCs are a subject of extensive study owing to their consistent clinical performance and pleasing aesthetic outcome. Subjected to periodic environmental stress, these items are prone to undesirable premature failure. We studied the effects of carbon nanotubes (CNT) and yttria-stabilized zirconia (YSZ), two high-strength and biocompatible ceramic additives, on the mechanical characteristics and the stability against oral rinsing of DRCs. To print dental resin matrices incorporating varying weights of carbon nanotubes (CNT) or yttria-stabilized zirconia (YSZ), the rheological behavior of the slurries was first assessed and then the DLP technique was applied. A systematic investigation was undertaken into the mechanical properties, including Rockwell hardness and flexural strength, and the oral rinsing stability of the 3D-printed composites. The DRC formulated with 0.5 wt.% YSZ demonstrated a remarkable hardness of 198.06 HRB and a flexural strength of 506.6 MPa, along with favorable oral rinsing stability. A fundamental viewpoint is provided by this study, useful in the design of advanced dental materials with incorporated biocompatible ceramic particles.