This study investigates the use of marble powder (MP), a local industrial by-product, as a partial sand substitute (7–25%) in self-compacting mortar (SCM) formulations incorporating crushed calcareous sand (fineness modulus = 3.0). Fresh-state tests (mini-cone flow, V-funnel) show that MP incorporation increases flow diameter while raising flow time, reflecting modified rheological behavior. Mechanically, compressive strength improves progressively with substitution rate, while flexural strength remains comparable to the reference mix, with optimal performance at 22%. Durability indicators — immersion absorption and capillary sorptivity — both decrease at moderate substitution levels (7–12%), indicating microstructural densification. Beyond 22%, a decline in durability performance is observed. These results confirm that MP can effectively correct the granulometric deficiency of coarse calcareous sand while enhancing SCM properties within a circular economy framework.
This work proposes a general methodology for the design and experimental validation of dual-arm robotic platforms intended for intelligent manipulation tasks in real-world environments. The proposed framework formalizes the complete engineering process, from the definition of functional requirements to the structural validation of the final prototype, ensuring reproducibility and adaptability across different applications. The methodology is organized into five main stages: (i) requirement analysis and context characterization; (ii) conceptual architecture definition; (iii) detailed mechanical design and structural analysis; (iv) prototype construction and integration; and (v) experimental validation and iterative refinement. Each stage defines its expected deliverables, evaluation metrics, and decision criteria to support systematic design progression. The approach is demonstrated through its implementation within the European project MANiBOT, where the framework guided the development of a modular bimanual robotic platform capable of integrating collaborative manipulators and conveyor subsystems for dual-arm manipulation. Structural testing, deflection measurements, and stability analyses confirmed the robustness and safety of the resulting design. Beyond this specific case, the proposed methodology provides a replicable and extensible design reference for research and industrial teams developing modular robotic structures, supporting the standardization of engineering practices in bimanual mobile robotics.
This study investigates the performance of a skirt sand pile (SSP) system beneath a circular shallow footing using three-dimensional finite element analysis calibrated against a large-scale experimental setup. The SSP, measuring 8.00 m in length and 1.00 m in diameter, was analyzed in a soft clay-sandy soil environment. The Mohr–Coulomb, hardening soil, and linear elastic models were employed to simulate the soil and structural elements. The innovative aspect of this study lies in the comprehensive evaluation of the SSP system's load-bearing capacity and settlement behavior, revealing its superior performance compared to deep cement pile (DCP). Numerical results demonstrated LBR improvements of 1.7 and 1.4 at settlement ratios (s/B%) of 10 % and 15 %, respectively, for the SSP, compared to LBRs of 1.3 and 1.1 for DCM. Additionally, the study explores the significant Influence of increasing SSP length (by 180 %), which resulted in a much greater increase in load-bearing capacity compared to similar changes in DCM. Another key innovation is the analysis of soil cohesion and friction angle effects, where increasing these parameters resulted in a reduction in settlement ratios from 36 % to 12 %, with the load-bearing capacity improving from 2 to 3.7. A significant and innovative aspect of this study is the soil-skirt sandpile interaction, which was found to have a much greater effect on the load-bearing capacity and settlement behavior than the traditional soil-deep cement pile interaction. This study provides critical insights into the efficacy of SSP systems in enhancing foundation performance, offering a cost-effective, efficient alternative to traditional deep cement pile, especially in layered clay-sand soil environments. The findings provide practical guidance for optimizing foundation design and improving the sustainability of geotechnical engineering solutions.
Reham Samaan, Abdelsalaam Mokhtar, Mohamed Saafan
et al.
Non-destructive evaluation techniques for assessing pile foundations have gained significant importance in geotechnical and structural engineering. This study thoroughly assesses the advancements in pile integrity testing from the early days toward current approaches. The study reviews the advancements in pile integrity testing, from early methodologies to modern approaches, while proposing a unique classification of techniques based on their focus: whether they involve the procedure of pile integrity testing or the interpretation of test findings. The analysis declares substantial advancements in testing methodologies, signal processing, and data interpretation techniques for evaluating the structural integrity of deep foundations. The concepts of wave propagation are essential for detecting and evaluating structural flaws, enabling engineers to check pile quality without affecting structural integrity. The review highlights significant issues in pile integrity assessment involving the influence of soil conditions, geometric changes, and material variability on test outcomes. Recent advances have improved the accuracy of flaw detection, enabling real-time monitoring of foundations. Advanced computer techniques now enable more precise test analysis and structural assessments, significantly improving foundation evaluation and safety. This investigation establishes the practical and theoretical basis for implementing advanced machine learning predictive models that combine previous records with pattern recognition algorithms, potentially converting traditional PIT interpretation from an uncertain process to a reliable and precise evaluation system. Conclusions suggest that existing pile integrity testing methods offer thorough solutions for early problem identification and quality assurance in foundation engineering, while also indicating new possibilities for future study and development.
Mohammad Reza Fathi, Soraya Birami, Alireza Payvar
et al.
The Viable System Model (VSM) is a foundational framework in organizational cybernetics, designed to manage complexity and ensure systemic viability in dynamic environments. Given the increasing importance of this model in addressing complex organizational challenges, the primary objective of this research is to conduct a comprehensive and systematic review of existing studies in the field of the Viable System Model. This review aims to identify and analyze the practical areas of this model, evaluate its challenges and opportunities in confronting contemporary systemic issues, and extract key insights from 21 peer-reviewed studies. By synthesizing and analyzing the findings of these studies, this paper intends to provide a clear and coherent picture of the Viable System Model's current state and future potential. The process of identifying relevant studies was conducted using the PRISMA method, which involved searching the Scopus database and performing manual searches. This study employs a bibliometric research design, utilizing a quantitative approach and combining bibliometric and network analysis to examine the landscape of VSM research. Key findings highlight VSM’s role in enhancing organizational resilience, improving decentralized decision-making, and enabling systemic adaptability. The integration of VSM with emerging technologies—such as artificial intelligence, digital twins, and big data analytics—demonstrates its potential to address contemporary organizational challenges. However, critical gaps remain, including limited empirical validation, insufficient applications in underrepresented sectors such as agriculture and education, and scalability issues for small and medium-sized enterprises (SMEs). The study emphasizes the need for longitudinal research, hybrid frameworks, and sector-specific models to enhance the theoretical and practical utility of VSM. By synthesizing recent applications and identifying research opportunities, this paper reinforces the significance of VSM as a robust approach to managing complexity and outlines pathways for future research.
Dynamic and structural geology, Engineering (General). Civil engineering (General)
Most seismic design codes provide formulas for estimating base shear and lateral loads. To determine lateral loads, the building's fundamental vibration period must be calculated, either theoretically or experimentally. However, there is no simplified equation that accurately calculates this parameter. This paper proposes a new simplified formula for computing the fundamental period of reinforced concrete moment-resisting frames (MRFs). The proposed formula is validated through eigenvalue analysis of the mathematical models of various building frames using finite element methods (FEM), with varying structural properties along their height. The proposed model achieved an average prediction error of around 4% and an R² (coefficient of determination) value of 0.999 when compared to FEM results, outperforming existing empirical formulas. A sensitivity analysis was conducted to identify the effect of each of the design parameters, accompanied by a comparative evaluation against some formulas from the literature. The novelty of the suggested method is that it can calculate the fundamental period more accurately and easily by considering the stiffness and seismic mass of the building.
Mechanical engineering and machinery, Structural engineering (General)
Ebtisam Yehia, Ayman Hussein Khalil, Ezz-Eldin Mostafa
et al.
In this paper, punching shear behavior of Ultra-High Performance Concrete (UHPC) was investigated experimentally and numerically. In this study, six 1350 * 1350 * 80 mm flat slabs with extended 200 mm column stubs above the slabs were constructed to study the effect of the increased strength of UHPC and its ductility with different concrete mix ratios and different column aspect ratios. All specimens contained steel fibers which increased slabs ductile behavior and shared directly in increasing punching shear capacity of the examined specimens. Numerical investigation was performed as nonlinear finite element analysis adopting ABAQUS software using concrete damaged plasticity model (CDPM), ABAQUS/Explicit. Compression and tensile behaviors of concrete were modeled by Hognestad Parabola and Bilinear tensile stress versus crack width respectively. The average strength of test specimens ranged between 164 MPa and 193 MPa in compression and 9.6 MPa to 13.1 MPa in tension. In this study, analysis parameters were concrete strength, column aspect ratio, column shape, and flexural reinforcement ratio. The results showed an increase in punching shear capacity in the six specimens ranged between 32% and a 20.8% relative to ACI 318-19 punching strength formula and Euro code EN1990.2012 formula, respectively.
Md Imam Faizan, Rituparna Chaudhuri, Shakti Sagar
et al.
Circulating cell-free mitochondrial DNA (cf-mtDNA) has been found in the plasma of severely ill COVID-19 patients and is now known as a strong predictor of mortality. However, the underlying mechanism of mtDNA release is unexplored. Here, we show a novel mechanism of SARS-CoV-2-mediated pro-inflammatory/pro-apoptotic mtDNA release and a rational therapeutic stem cell-based approach to mitigate these effects. We systematically screened the effects of 29 SARS-CoV-2 proteins on mitochondrial damage and cell death and found that NSP4 and ORF9b caused extensive mitochondrial structural changes, outer membrane macropore formation, and the release of inner membrane vesicles loaded with mtDNA. The macropore-forming ability of NSP4 was mediated through its interaction with BCL2 antagonist/killer (BAK), whereas ORF9b was found to inhibit the anti-apoptotic member of the BCL2 family protein myeloid cell leukemia-1 (MCL1) and induce inner membrane vesicle formation containing mtDNA. Knockdown of BAK and/or overexpression of MCL1 significantly reversed SARS-CoV-2-mediated mitochondrial damage. Therapeutically, we engineered human mesenchymal stem cells (MSCs) with a simultaneous knockdown of BAK and overexpression of MCL1 (MSCshBAK+MCL1) and named these cells IMAT-MSCs (intercellular mitochondrial transfer-assisted therapeutic MSCs). Upon co-culture with SARS-CoV-2-infected or NSP4/ORF9b-transduced airway epithelial cells, IMAT-MSCs displayed functional intercellular mitochondrial transfer (IMT) via tunneling nanotubes (TNTs). The mitochondrial donation by IMAT-MSCs attenuated the pro-inflammatory and pro-apoptotic mtDNA release from co-cultured epithelial cells. Our findings thus provide a new mechanistic basis for SARS-CoV-2-induced cell death and a novel therapeutic approach to engineering MSCs for the treatment of COVID-19.
Chiara Ferrero, Paulo Barbosa Lourenço, Chiara Calderini
A prolonged seismic sequence struck the regions of Central Italy between August 2016 and January 2017, causing several fatalities and widespread damage to the built environment. The main objective of this work was to study the structural and seismic behavior of “Pietro Capuzi” school, located in Visso, in the Marche region, which was severely damaged by the 2016-2017 Central Italy Earthquake. A 3D finite element (FE) model of the entire school was prepared, adopting a macro-modeling approach to represent masonry materials. An eigenvalue analysis was initially performed in order to identify the dominant modes of vibration of the structure and to calibrate the numerical model according to the results of the dynamic identification tests. Afterwards, nonlinear static analyses were performed on the calibrated FE model to evaluate the seismic response of the structure. Finally, the numerical results obtained in terms of crack pattern and failure mechanisms were compared with the damage experienced by the building. The numerical model proved to accurately predict the seismic response exhibited by the structure during the past seismic events.
Mechanical engineering and machinery, Structural engineering (General)
This paper provides a methodology to determine the upper and lower limits of concession period of public private partnerships that would be useful both to the public and the private sector with the impact of risks and uncertainties taken into consideration. The model uses Monte Carlo simulation to evaluate the effect of risks and uncertainties on the concession period. Net present value (NPV) analysis is used for financial evaluation. To demonstrate the applicability of the proposed model, hypothetical public private partnership (PPP) rail way project in Egypt was used a case study. After applying the model accurate results are obtained. However, using this model gives the practitioners a clearly vision about the value of concession period insuring that the private sector doesn’t lose his investment and the government can benefit from the project before end of its service life.
This Special Issue (SI) of Applied Sciences on Development and Application of NonlinearDissipative Devices in Structural Vibration Control contains papers that focus on the developmentand application of innovative nonlinear dissipative systems that mitigate the potentially catastrophiceffects of extreme loading by incorporating new materials or effective mechanical control technologies [...]
The paper presents the fatigue test results including the cracks growth in the composite zirconium-steel subjected to oscillatory bending. Specimens of square cross-section without melted layer and with a melted layer were tested. In the specimens the net ratio of thickness of steel to zirconium layers was h1 : h2 = 2.5 : 1. It was observed that a higher fraction of the intermetallic inclusions near the interface increase the fatigue life. Two different interaction mechanisms between a crack and interface were observed.
Mechanical engineering and machinery, Structural engineering (General)
Jembatan yang terletak di perumahan Jondul Kecamatan Limapuluh Kota Pekanbaru ini dibangun pada tahun 1993 merupakan akses penghubung bagi pejalan kaki maupun alat transportasi. Jembatan ini terbuat dari material kayu. Kondisi struktur jembatan kini telah rubuh dan membutuhkan pembangunan kembali. Penelitian ini dilakukan dengan tujuan untuk merencanakan struktur atas jembatan dengan metode beton bertulangan, bentang jembatan 20 meter dengan lebar 7 meter. Perencanaan struktur terdiri dari tiang sandaran, trotoar, pelat lantai kendaraan, gelagar dan balok diafragma. Perhitungan struktur jembatan mengacu pada RSNI T-12-2004 (Standar Perencanaan Struktur Beton Untuk Jembatan) dan RSNI T-02-2005 (Standar Perencanaan Pembebanan Jembatan). Perhitungan gaya dalam dihitung secara manual menggunakan analisa struktur. Berdasarkan analisa dan perhitungan pada struktur atas jembatan diperoleh hasil perencanaan tiang sandaran direncanakan dengan dimensi 10 cm x 15 cm menggunakan tulangan 2D10, trotoar direncanakan tebal 20 cm menggunakan tulangan D13–140, pelat lantai kendaraan direncanakan tebal 20 cm menggunakan tulangan D13–130, gelagar direncanakan dengan dimensi 60 cm x 125 cm menggunakan tulangan 12D40, balok diafragma direncanakan dengan dimensi 30 cm x 50 cm menggunakan tulangan 4D16.
This special issue of U. Porto Journal of Engineering includes a selection of papers that were presented at the Symposium on Civil Engineering held during the 1st Doctoral Congress in Engineering (DCE 2015). A set of very interesting papers were presented at that session and their authors were invited to submit an extended version of their papers for inclusion in a special issue of this journal. After the reviewing process five papers have been selected covering mainly two different topics: transport infrastructures and structural dynamics and seismic analysis. The first topic is raised in an interesting paper entitled Freeway geometric design comparison between Mexico and Portugal. The second is brought up in four papers which cover very important and updated subjects, such as structural analysis, seismic loading characterization and losses’ estimation. All papers selected include original contributions and I´m strongly convinced that they will be a very interesting tool for the study of the referred subjects. Finally, I would like to congratulate all authors of the published papers and emphasize that the main objectives of this congress have been achieved, namely in what concerns the training process of the students enrolled in the Doctoral Program in Civil Engineering at FEUP.
Basic studies in system science explore the theories, principles, and properties of abstract and concrete systems as well as their applications in system engineering. Systems are the most complicated entities and phenomena in abstract, physical, information, cognitive, brain, and social worlds across a wide range of science and engineering disciplines. The mathematical model of a general system is embodied as a hyperstructure of the abstract system. The theoretical framework of system science is formally described by a set of algebraic operations on abstract systems known as system algebra. A set of abstract structures, properties, behaviors, and principles is rigorously formalized in contemporary system theories. Applications of the formal theories of system science in system engineering, intelligent engineering, cognitive informatics, cognitive robotics, software engineering, cognitive linguistics, and cognitive computing are demonstrated, which reveals how system structural and behavioral complexities may be efficiently reduced in system representation, modeling, analysis, synthesis, inference, and implementation.