Search Results (105)

Recent studies highlight blockchain’s potential to enhance residential energy efficiency by enabling traceable, verifiable, and incentivized household actions. This research focuses on optimal organizational models, technology choices, and measurement systems needed to support carbon reduction at the residential level through blockchain. To do so, a multiple-case study was conducted, analyzing six companies that leverage blockchain in the context of carbon markets. Data have been collected through direct, semi-structured interviews with informants from each company. Results from the six cases have been analyzed through a cross-case comparison and clustered to identify three different archetypes of business ecosystem. The results suggests that blockchain supports residential energy efficiency and carbon markets through behavioural incentives, infrastructural integration and hybrid measurement, and reporting and verification systems. They also indicate that blockchain effectiveness depends less on specific protocols than on aligning technological design, governance, and ecosystem context across civic, financial, and institutional models. Full article

Large-format thin ceramic panels are increasingly used in ventilated façade systems due to their reduced weight, high durability and architectural versatility. However, their reduced thickness and large dimensions require reliable anchoring solutions capable of safely transferring wind loads to the supporting structure. This study investigates the structural behaviour of a concealed mechanical anchoring system for large-format porcelain stoneware panels installed in ventilated façades. An experimental campaign was carried out using a full-scale façade prototype representative of real construction conditions. The specimen was subjected to incremental wind pressure and suction loading in a controlled laboratory environment while monitoring the deformation of the ceramic panels, backing support layer and aluminium substructure. The experimental results show that the ceramic panels exhibited stable structural behaviour without cracking or anchor pull-out under pressure levels up to 3006 Pa, exceeding twice the design service pressure. The maximum estimated deflection at the service pressure level (1300 Pa) was 5.7 mm, significantly below the admissible limit defined by the L/200 serviceability criterion. A simplified mechanical analysis based on classical bending theory confirmed that the stresses induced in the ceramic panels remained well below their flexural strength. The results demonstrate that the investigated concealed anchoring system provides reliable structural performance for large-format thin ceramic panels subjected to wind loading in ventilated façade systems, while the simplified analytical verification confirms the mechanical consistency between the measured deformation levels and the flexural capacity of the ceramic material. Full article

Flying Ad Hoc Networks (FANETs) formed by cooperative Unmanned Aerial Vehicles (UAVs) require formally proven secure and resource-efficient authentication because open wireless channels allow active adversaries to inject commands, replay traffic, and impersonate nodes. Conventional certificate-based mechanisms impose key management overhead and remain vulnerable under device capture, while existing lightweight and Physical Unclonable Function (PUF)-assisted proposals commonly assume stable connectivity, lack formal adversarial verification, or are evaluated only through simulation. This paper presents a lightweight PUF-assisted authentication protocol designed for dynamic multi-hop FANET operation. The scheme provides mutual UAV–Ground Station (GS) authentication and session key establishment and further enables secure UAV–UAV communication using an off-path ticket mechanism that eliminates continuous infrastructure dependence. The protocol is constructed through verification-driven refinement and formally analysed under the Dolev–Yao model, establishing authentication and session key secrecy and resistance to replay and impersonation attacks. Implementation-oriented latency measurements on Raspberry-Pi-class embedded platforms demonstrate that cryptographic processing time can be further reduced with hardware improvements, while the overall end-to-end delay is still largely determined by channel conditions and connection behaviour. Comparative evaluation shows reduced communication cost and broader security coverage relative to existing UAV authentication schemes, indicating practical deployability in large-scale FANET environments. Full article

A hybrid quill shaft for a multifunctional machine tool centre combines a conventional steel body with a wound composite insert that significantly enhances structural stiffness and dynamic properties. This paper presents a methodologically rigorous approach to the design and validation of a hybrid quill shaft, encompassing material optimisation through the NSGA-II evolutionary algorithm, experimental modal analysis, and verification of the influence of an active pre-tensioning anchor system on the compensation of elastic deformations. A finite element model was coupled with an optimisation tool evaluating eight fibre types across 786 iterations. Results unequivocally demonstrated the superiority of M55J fibre with ±88° orientation as the optimal compromise between stiffness (13.2% reduction in deflection), weight (3% reduction), and cost (4.2% cost increase). Composite safety was ensured through the three-dimensional Tsai-Wu strength criterion applied as a constraint. Experimental validation on an assembly with a hydraulic pre-tensioning system demonstrated symmetrical quill shaft behaviour (±0.07 mm/m) and agreement with finite element analysis (9.5% deviation). Numerical modal analysis revealed a pronounced decrease in natural frequencies with increasing overhang (from 308 Hz to 58 Hz). The resulting design incorporating M55J fibres, 2345 mm length, and epoxy resin in a 60:40 fibre-to-matrix ratio represents a practically implementable solution for enhanced precision and productivity in modern machine tool centres. Full article

Since a significant part of the Italian territory was not seismically classified until 2003, most existing bridges have been designed—for decades—disregarding earthquake-induced excitations. In fact, this means that load-bearing devices and shear keys of presently in-service infrastructures may not be up to current codes, both in terms of resistance and displacement capacity. Robust investigations are hence required for verifications and possible retrofit. In this study, the seismic behaviour of a case study post-tensioned concrete bridge built in the 1980s is numerically analysed. The examined structure is 440 m long and composed of nine spans, built with precast segments using the balance cantilever construction method. The deck is divided into two parts connected by a hinged joint in the middle of the central span, obtained with three shear keys and originally designed to allow for thermal expansion only. Most importantly, the mid-span hinge, the end joints and the bearing devices were originally designed without considering the effects of seismic action. In order to preliminarily investigate the performance of devices and joints, the case study bridge is analysed by means of non-linear dynamic time history simulations, formulating different hypotheses about the non-linear behaviour of the load bearings. Forces and displacements over time are obtained for a set of seven accelerograms, and maximum values are compared to the capacity of the bridge devices. Results are then critically discussed. Full article

Corrugated insect wings inspire biomimetic aerodynamic design, yet their behaviour at low and transitional Reynolds numbers remains not fully understood. This study presents a three-dimensional computational analysis of flow over an infinite corrugated wing across Reynolds numbers from 10 to 10,000 and angles of attack from −5 to 20°, with emphasis on spanwise effects. An expanded verification and validation procedure ensured numerical reliability. At the lowest Reynolds numbers, the flow is steady and largely two-dimensional, with localised recirculation zones. As Reynolds numbers or angles of attack increase, the flow transitions to periodic vortex shedding, and three-dimensional structures appear. At a Reynolds number of ten thousand, periodic shedding occurs at zero degrees incidence, indicating a shift toward turbulent or bluff body-like behaviour. The examined corrugated profile does not exhibit a lift-to-drag benefit over smooth aerofoils in steady gliding, although root section corrugation helps delay separation in transitional regimes. This behaviour reflects mechanisms used by dragonflies to maintain stable gliding despite textured wings. By extending flow regime classification, the study identifies conditions where two-dimensional assumptions fail and highlights the influence of spanwise flow structures. These findings deepen understanding of insect wing aerodynamics and support biomimetic design of future wings. Full article

Covered karst collapse is a key geotechnical hazard in infrastructure construction in karst regions of China. In particular, strata consisting of an overlying clay layer and an underlying sand layer are prone to abrupt collapse induced by sand leakage under construction disturbances, which poses serious risks to pile foundation safety. To clarify the disaster-forming mechanism and develop a quantitative analysis method, this study investigates the mechanical behaviour of the entire collapse process by combining theoretical analysis with numerical simulation. A continuous mechanical analysis framework is established that follows the sequence from sand layer leakage to cavity expansion and then clay layer instability. Within this framework, a calculation model for the angle of repose of the sand layer is proposed that considers seepage and confined pressure effects. Simultaneously accounting for the influence of the casing, stability models for overall and localised collapses are developed using limit equilibrium theory. A comprehensive safety factor criterion K_c based on the critical span (or radius) is then proposed, leading to a linked evaluation method that couples the potential span of the sand layer with the ultimate span of the clay layer. The results show that an increase in Δh/h significantly reduces the angle of repose of the sand layer; the mechanical mechanism is confirmed whereby an increase in the roof span leads to shear stress exceeding the soil’s shear strength, thus triggering instability; the proposed safety factor K_c can effectively predict both overall and localised collapse, and case verification demonstrates that the predicted spans match well with actual collapse dimensions. The results provide a theoretical and technical basis for risk prediction, as well as for the prevention and control of pile foundation construction in karst areas. Full article

Asserting program correctness is a longstanding challenge in software development that consumes lots of resources and manpower. It is often accomplished through software testing at various levels. One such level is unit testing, where the behaviour of individual components is tested. In this paper, we introduce the concept of test analysis, which instead of executing unit tests, analyses them to establish their outcome. This is line with previous approaches towards using formal methods for program verification; however, we introduce a middle layer called the test analysis framework, which allows for the introduction of new capabilities. We (briefly) formalize ordinary testing and test analysis to define the relation between the two. We introduce the notion of rich tests with a syntax and semantic instantiated for C. A prototype framework is implemented and extended to handle property-based stubbing and non-deterministic string variables. A few select examples are presented to demonstrate the capabilities of the framework. Full article

This paper presents an analytically derived optimal control strategy for wound-rotor synchronous machines (WRSM) based on minimising the Joule losses in both the stator and rotor windings. The presented control strategy is analysed in terms of analytical derivation, machine current ratios, working regions and constraints. It is experimentally verified on a salient-pole wound-rotor synchronous machine with strongly non-linear equivalent circuit parameters. The verification was performed in two stages: first, considering constant equivalent circuit parameters while assessing strong non-linear behaviour of the machine leading to significant discrepancies in the resulting machine torque. In the second stage, after determination of non-linear machine parameters using measured flux maps, identical control methodology is analysed in terms of variations in ratios between machine currents. Using pre-calculated current ratios the same control methodology is extended for machines with strongly non-linear equivalent circuit parameters and verified in a real environment. The measurement confirms expected machine behaviour in all available control regions achievable by used synchronous motor as well as limits between these control regions. The results of the verification in a real environment show a discrepancy of approximately 5% in measured machine torque in comparison to expected value confirming the validity of the analytically derived approach and introduced modifications for machines with non-linear equivalent circuit parameters. Full article

Managing hydraulic behaviour and water quality in semi-arid, transboundary rivers such as the Talas River in Kazakhstan requires reliable numerical tools for predicting free-surface flow through porous hydraulic structures. This study develops and verifies a two-dimensional computational fluid dynamics (CFD) framework for simulating free-surface water flow through porous media and demonstrates its applicability to a real river reach of the Talas in the Zhambyl region. The model combines the Volume of Fluid (VOF) method with the Darcy–Forchheimer formulation to represent porous resistance, while turbulence is described by the RNG k–$\epsilon$ model, and pressure–velocity coupling is handled by the PISO algorithm. Model verification is conducted against a classic dam-break experiment involving a rectangular porous barrier across a laboratory channel. The simulations successfully reproduce the main experimental observations, including rapid drawdown after gate opening, formation and attenuation of the free-surface wave, localized depression above the porous insert, and the subsequent approach to a quasi-steady state. Time histories of water levels at control points and the spatial progression of the wet front show close agreement with measurements. Using the validated setup, a site-specific two-dimensional domain for the Talas River is constructed to analyse the hydraulic influence of a porous bar. The model quantifies velocity redistribution and energy dissipation across the porous patch and provides physically consistent flow fields suitable for engineering assessments under various discharge conditions. Full article

Morphoeic basal cell carcinoma (mBCC) has a higher risk of local recurrence than the more indolent nodular (nodBCC) subtype. Little is known about the genetic and molecular makeup of mBCC that determines its invasive behaviour: a comparison of mBCC with nodBCC was carried out. Whole-exome sequencing (WES) of 20 BCC tumours (10 eyelid morphoeic and 10 nodular) underwent driver gene detection using OncodriveFM and MutSigCV, followed by a randomisation analysis procedure. Samples underwent RNA sequencing, gene-set enrichment analysis and candidates verified by RT-PCR. PTCH1, FLNB, and double-knockdown human keratinocyte models were used to validate phenotype and gene expression. Hedgehog pathway analysis of 20 additional BCCs underwent immunostaining verification. Our analysis revealed FLNB as a potential driver with a mutational cluster in FLNB Filamin domain 24 and a 4-fold reduction in expression compared to normal eyelids in mBCC only. FLNB knockdown demonstrated an mBCC phenotype. Aberrant Gli2 dominant hedgehog (Hh) signalling was seen in mBCC on three molecular levels: mutational significance, transcriptome profile, and protein expression. Gli2-dominant Hh overexpression was seen in the tumour plus stroma of eyelid morphoeic but not nodular BCC. FLNB is a potential tumour suppressor, with its loss producing a morphoeic phenotype in vitro. Full article

Cross-laminated timber (CLT) panels, composed of orthogonally bonded layers, are often used in civil engineering and tall constructions owing to their sustainability, prefabrication advantages and favourable mechanical performance. However, their multilayered, anisotropic and shear-compliant nature presents significant challenges for accurate structural modelling and performance prediction. This study presents an advanced numerical approach to analysing the bending behaviour of CLT panels using the finite element method (FEM) in combination with the classical laminate theory. The proposed plate model was implemented in FlexPDE and validated through a series of three-point bending experiments on three-layer spruce panels. Further verification was conducted using commercial FEM software—Dlubal, incorporating both linear elastic and non-linear damage models, and Abaqus, where a three-dimensional solid model with a cohesive zone formulation captured progressive delamination and local failure in the glued layers. Comparison of the experimental data and numerical simulations revealed strong agreement in load–deflection behaviour, stiffness evolution and damage localisation. The framework we developed accurately reproduces both the global and the local mechanical responses of CLT panels while maintaining computational efficiency. Our results confirm the reliability of laminate theory-based FEM formulations in the design, optimisation and safety assessment of cross-laminated timber structures in building applications. Full article

The article is devoted to the issues of designing the exploitation of a seam deposit in the boundary areas of underground mines in terms of minimizing the risk of dynamic phenomena. Its main goal was to attempt to demonstrate the relationship between the method of extracting resources trapped in the boundary pillar and the magnitude of the induced seismicity of the rock mass accompanying this process. The substantive considerations concerned the single-wall model and were divided into two main parts—theoretical and verification. As part of the theoretical piece, based on model studies, a geomechanical assessment of the impact of the working face advance on changes in the stress–strain behaviour occurring in the burst-prone layer in terms of the possible loss of continuity of its original structure was carried out. The starting point for the key analyses were the results of numerical simulations based on the algorithms of S. Knothe and W. Budryk’s theories in combination with classical solutions of the mechanics of deformable bodies. Two variants of mining operations in a two-sided environment of goaf were considered, differing in the direction of progress, the degree of constraint of the start and end of the face advance, and mining circumstances in the vicinity of both sides of the advancing face. As part of the verification piece, the results of model analyses were related to an example polygon of a crossing longwall in one of the functioning, rockburst USCB hard coal mines. The scope of the research included a comparison of the experimentally indicated zones of occurrence of tremor-favourable effort processes in the roof of the seam with the actual location of the seismic phenomena foci recorded during the ongoing exploitation. The considerations included in the work formed the basis for formulating conclusions of a cognitive and applicable nature. Full article

A context-aware system is a system that adapts its behaviours in response to changes in the system’s environment (i.e., context). Ensuring the correctness of such a system is difficult because the state of the environment changes frequently in an unpredictable manner according to the laws of physics. Hence, formal verification techniques like model-checking and theorem proving do not work in many cases. Runtime Verification (RV) is a lightweight formal verification technique that consists of checking at runtime whether the execution of the system violates the requirements of the system. The Calculus of Context-aware Ambients (CCA) is a process calculus for modelling context-aware systems and reasoning about their behaviours. This paper proposes an RV tool for CCA, called ccaRV. Given a model of a system in CCA and a property of the system written in LTL (Linear Temporal Logic), ccaRV verifies automatically at runtime if the execution of the system violates the property. We propose a semantic approach to RV, where the RV mechanism is defined at the semantics level and not as an add-on. A consequence of this is that there is no need for generating a monitor from the property specification nor for the instrumentation of a system during verification. We define a labelled reduction relation for CCA, where the labels are used to capture the execution traces at the semantics level. Then we extend LTL with spatial operators and context expressions in order to formulate properties about the system context. We use a case study of the MQTT (Message Queue Telemetry Transport) protocol to evaluate the proposed RV approach. The results show that the ccaRV tool is scalable and its decisions are accurate. Full article

The presented research aims to find a data-driven formula for the compressive stress–strain behaviour of closed-cell aluminium foams with respect to the apparent density of the material. This is a continuation and new development of an earlier study by the authors. In the previous step, 500 artificial neural network models were built and trained on experimental results from compression tests and then evaluated based on, among other factors, mean absolute relative errors for training and verification stages. In this step, the evaluation of networks is amended, and criteria are introduced that are connected with the mechanical characteristics of the material, i.e., the plateau stress and quasi-elastic gradient. A weighted condition of all measures is proposed. Based on the amended conditions, a neural network model with a weighted mean absolute relative error of $\cong 5\%$ is chosen and presented, together with the mathematical equation for its stress–strain–density relationship $\sigma =f\left(\epsilon ,\rho \right)$ over a range of material apparent densities $\rho \in ⟨0.2;0.3⟩ \mathrm{g}/{\mathrm{c}\mathrm{m}}^3$. Experimental relationships for compressive strength and plateau stress are also presented. Full article