Reinforced concrete (RC) beams strengthened with carbon-fabric-reinforced cementitious matrix (CFRCM) systems have shown potential for restoring flexural performance, yet their effectiveness under different corrosion levels remains insufficiently understood. This study presents a numerical investigation of the flexural behaviour of simply supported RC beams externally strengthened with CFRCM plates. Refined finite element models (FEMs) were developed by explicitly incorporating the steel–concrete bond-slip behaviour, the carbon fabric (CF) mesh–cementitious matrix (CM) interface, and the CFRCM–concrete substrate interaction and were validated against experimental results in terms of failure modes, load–deflection responses, and flexural capacities. A parametric study was then conducted to examine the effects of CFRCM layer number, steel corrosion level, and longitudinal reinforcement ratio. The results indicate that the baseline flexural capacity can be fully restored only when the corrosion level remains below approximately 15%; beyond this threshold, none of the CFRCM configurations achieved full recovery. The influence of the reinforcement ratio was found to depend on corrosion severity, while increasing CFRCM layers enhanced flexural performance but exhibited saturation effects for thicker configurations. In addition, corrosion level and CFRCM thickness jointly influenced the failure mode. Comparisons with design predictions show that bilinear CFRCM constitutive models are conservative, whereas existing FRP-based design codes provide closer agreement with numerical and experimental results.
The purpose of this paper is two-fold. First we show that Kim's building-up construction of binary self-dual codes is equivalent to Chinburg-Zhang's Hilbert symbol construction. Second we introduce a $q$-ary version of Chinburg-Zhang's construction in order to construct $q$-ary self-dual codes efficiently. For the latter, we study self-dual codes over split finite fields \(\F_q\) with \(q \equiv 1 \pmod{4}\) through three complementary viewpoints: the building-up construction, the binary arithmetic reduction of Chinburg--Zhang, and the hyperbolic geometry of the Euclidean plane. The condition that \(-1\) be a square is the common algebraic input linking these viewpoints: in the binary case it underlies the Lagrangian reduction picture, while in the split \(q\)-ary case it produces the isotropic line governing the correction terms in the extension formulas. As an application of our efficient form of generator matrices, we construct optimal self-dual codes from the split boxed construction, including self-dual \([6,3,4]\) and \([8,4,4]\) codes over \(\GF{5}\), MDS self-dual \([8,4,5]\) and \([10,5,6]\) codes over \(\GF{13}\), and a self-dual \([12,6,6]\) code over \(\GF{13}\). These structural statements are accompanied by a Lean~4 formalization of the algebraic core.
Rauan Lukpanov, Zhibek Zhantlessova, Duman Dyussembinov
et al.
The study considers the development of a paraffin-based additive for cement–sand injection mortars intended for deep soil stabilisation under the geological conditions of Central Kazakhstan. The present study investigates the influence of the additive on mobility, water separation, setting time, and strength characteristics of mortars, for concentrations ranging from 0.2 to 1.0% by cement mass. The findings demonstrated that the additive enhanced the slump flow area by up to 62%, diminished water separation by 30–32% and extended the setting time by 45–76%. It was demonstrated that compressive and flexural strength were preserved with moderate increases of up to 8–9% in comparison with the reference mixture. The range of 0.6–0.8% was identified as optimal, providing enhanced mobility and stability while maintaining structural integrity. The findings indicate that paraffin-based additives can be effectively applied in deep cementation technologies for enhancing the injectability and performance of soil stabilization mixtures.
Voronoi diagrams are essential geometrical structures with numerous applications, particularly astrophysics-driven finite volume methods. While serial algorithms for constructing these entities are well-established, parallel construction remains challenging. This is especially true in distributed memory systems, where each host manages only a subset of the input points. This process requires redistributing points across hosts and accurately computing the corresponding Voronoi cells. In this paper, we introduce a new distributed construction algorithm, which is implemented in our open-source C++ 3-dimensional Voronoi construction framework. Our approach leverages Delaunay triangulation as an intermediate step, which is then transformed into a Voronoi diagram. We introduce the algorithms we implemented for the precise construction and our load-balancing approach and compare the running time with other state-of-the-art frameworks. MadVoro is a versatile tool that can be applied in various scientific domains, such as mesh decomposition, computational physics, chemistry, and machine learning.
In this note, we show how certain everywhere-regular real rational function solutions of the KP1 equation ("multi-lumps") can be constructed via the polynomial analogs of theta functions from singular rational curves with cusps. We use two methods, one direct and the other producing a degeneration of the well-understood soliton solutions from nodal singular curves. The second approach can be seen as a variation on the long-wave limit technique of Ablowitz and Satsuma, as developed by Zhang, Yang, Li, Guo, and Stepanyants. We present an explicit example of a three-lump solution constructed via the polynomial analog of the theta function from a rational curve with two cuspidal singular points, each with semigroup $\langle 2,5\rangle$. (In the theory of curve singularities, these are known as $A_4$ double points.) We conjecture that these ideas will generalize to give similar $M$-lump solutions with $M = \frac{N(N+1)}{2}$ for $N > 2$ starting from rational curves with two singular points with semigroup $\langle 2,2N+1\rangle$ ($A_{2N}$ double points). We also show a five-lump solution obtained from a curve with two cusps with semigroup $\langle 3,4\rangle$. Similar solutions have been constructed by other methods previously; our contribution is to show how they arise from the algebraic-geometric setting by considering singular curves with several cusps, as in previous work of Agostini, Celik, and Little.
Publicly-verifiable quantum money has been a central and challenging goal in quantum cryptography. To this day, no constructions exist based on standard assumptions. In this study, we propose an alternative notion called quantum cheques (QCs) that is more attainable and technologically feasible. A quantum cheque can be verified using a public-key but only by a single user. Specifically, the payer signs the quantum cheque for a particular recipient using their ID, and the recipient can validate it without the assistance of the bank, ensuring that the payer cannot assign the same cheque to another user with a different ID. Unlike quantum money, QCs only necessitate quantum communication when a cheque is issued by the bank, meaning all payments and deposits are entirely classical! We demonstrate how to construct QCs based on the well-studied learning-with-errors (LWE) assumption. In the process, we build two novel primitives which are of independent interest. Firstly, we construct signatures with publicly-verifiable deletion under LWE. This primitive enables the signing of a message $m$ such that the recipient can produce a classical string that publicly proves the inability to reproduce a signature of $m$. We then demonstrate how this primitive can be used to construct 2-message signature tokens. This primitive enables the production of a token that can be used to sign a single bit and then self-destructs. Finally, we show that 2-message signature tokens can be used to construct QCs.
The warming climate is expected to increase environmental thermal loading on urban buildings. Green infrastructure enhancements have been widely supported as a means to address the resulting heat-related risks, with the challenge of realising enhancements in densely built cities necessitating the consideration of vegetated architectural features. Early efforts promoted horizontal greening, although in recent years ‘vertical greening’ has gained increased prominence. This paper examines the hypothesis that the wider implementation of the latter typology could serve to enhance urban climate resilience, and does so by applying an analysis pathway including the coupling of a novel one-dimensional vertical greening model (VGM) with an urban climate simulation framework to estimate the microclimate and energy-use implications of neighbourhood-scale vertical greening. The simulation results highlighted immediate thermal relief to canyon pedestrians, as well as net annual space-conditioning energy savings for the canyon buildings. These benefits, however, were modest, with a relatively pronounced influence offered for the urban neighbourhood than suburban, and with the living wall category than green facade application. Although the annual savings present potential for the wider implementation in temperate climates, the influence is insufficient to offer it as an exclusive solution, with any widescale application also requiring assessment against other ecosystem benefits and maintenance costs. Practice relevance The study contributes to the evidence base supporting both policy and practice targeting the delivery of green infrastructure enhancements, by presenting evidence that addresses widescale evergreen vertical greening application potential in temperate climates. It emphasises the need for key decision-makers considering such strategies to acknowledge the magnitude of thermal and energy-use benefits that can be reasonably expected, and identifies the most appropriate application typology and siting to prioritise. Finally, the study demonstrates the application of a novel VGM-coupled analysis pathway, which allows for such considerations to be frontloaded to building and urban design approaches. This in turn will offer technically sound reasoning when specifying such strategies and prevent costly failures of future installations.
Architectural engineering. Structural engineering of buildings
Concrete is by a substantial margin the most widely used construction material. Projections indicate that the demand for concrete it will continue to increase to sustain the development of emerging economies. This paper presents a new perspective of low-carbon concrete by refocusing on the actual final product, highlighting the tremendous CO2 saving opportunities of reducing the total paste volume of concrete while simultaneously using high performance, low-clinker cements in the so-called two-fold strategy (low clinker content, low paste volume concrete formulations). Different aspects of low paste volume concrete formulations are discussed based on a combination of published and new concrete performance data, showing the potential for CO2 savings of the strategy and the technical opportunities to retain the robustness and reliability that make concrete such a versatile and widely used material. Chemical admixtures play a crucial role in reaching those objectives, as they enable to reduce the cement content while retaining the needed workability (slump and slump retention) for each application. The key issues relating to using those admixtures in low carbon concrete are highlighted.
Garavaglia Saul, Bruschi Alex, Fanale Francesco
et al.
The DTT tokamak, whose construction is starting in Frascati (Italy), will be equipped with an ECRH system of 16 MW for the first operation phase and with a total of 32 gyrotrons (170 GHz, ≥ 1 MW, 100 s), organized in 4 clusters of 8 units each in the final design stage. To transmit this large number of power beams from the gyrotron hall to the torus hall building a Quasi-Optical (QO) approach has been chosen by a multi-beam transmission line (MBTL) similar to the one installed at W7-X Stellarator. This compact solution, mainly composed of mirrors in “square arrangement” shared by 8 different beams, minimizes the mode conversion losses. The single-beam QOTL is used to connect each gyrotron MOU output to a beam-combiner mirror unit and, after the MBTL, from a beam-splitter mirror unit to the exvessel and launchers sections located in the equatorial and upper ports of 4 DTT sectors. A novelty introduced is that the mirrors of the TLs are embodied in a vacuum enclosure, using metal gaskets, to avoid atmospheric absorption losses and microwave leaks. The TL, designed for up to 1.5 MW per single power beam, will have a total optical path length between 84 m and 138 m from the gyrotrons to the launchers. The main straight section will travel along an elevated corridor ~10 m above the ground level. The development of the optical design reflects the constraints due to existing buildings and expected neutron flux during plasma operation. In addition, the power throughput of at least 90% should be achieved.
Silvia Vilčeková, Peter Mésároš, Eva Krídlová Burdová
et al.
This article is focused on analyzing roof structure from environmental impact indicators and circularity point of view. The life cycle analysis of the roof structure includes the product phase, transport from the factory gate to the site, operational energy and operational water phase, and an end-of-life phase. Three end-of-life scenarios for built-in materials are designed to observe the reduction in environmental impacts throughout the life cycle of the structure. Scenario 1 mainly considers waste incineration, which accounts for almost 77% of the end-of-life phase. In addition, landfilling (15.4%) and recycling (7.7%) are considered. In scenario 2, landfilling accounts for 38.5% and incineration also accounts for 38.5%. Recycling (15.4%) and downcycling (7.6%) are also considered. In scenario 3, recycling and reuse represent 46.1% and 38.5%, respectively. Incineration (7.7%) and downcycling (7.7%) are also considered. The lifetime considered is 50 years and the functional unit is 1 m<sup>2</sup>. One-Click LCA software was used for the analysis. Results for GWP-fossil are 415 kgCO<sub>2eq</sub>, 381 kgCO<sub>2qe</sub> and 362 kgCO<sub>2eq</sub> for scenarios 1, 2 and 3. The circulation score of the roof composition for three scenario is determined to be 2%, 16% and 36%. It can be concluded that the end-of-life phase of the materials influenced these results to a large extent.
The introduction of assistive construction robots can significantly alleviate physical demands on construction workers while enhancing both the productivity and safety of construction projects. Leveraging a Building Information Model (BIM) offers a natural and promising approach to driving robotic construction workflows. However, because of uncertainties inherent in construction sites, such as discrepancies between the as-designed and as-built components, robots cannot solely rely on a BIM to plan and perform field construction work. Human workers are adept at improvising alternative plans with their creativity and experience and thus can assist robots in overcoming uncertainties and performing construction work successfully. In such scenarios, it is critical to continuously update the BIM as work processes unfold so that it includes as-built information for the ensuing construction and maintenance tasks. This research introduces an interactive closed-loop digital twin framework that integrates a BIM into human-robot collaborative construction workflows. The robot's functions are primarily driven by the BIM, but it adaptively adjusts its plans based on actual site conditions, while the human co-worker oversees and supervises the process. When necessary, the human co-worker intervenes to help the robot overcome the encountered uncertainties. A drywall installation case study is conducted to verify the proposed workflow. In addition, experiments are carried out to evaluate the system performance using an industrial robotic arm in a research laboratory setting that mimics a construction site and in the Gazebo simulation. Integrating the flexibility of human workers and the autonomy and accuracy afforded by the BIM, the proposed framework offers significant promise of increasing the robustness of construction robots in the performance of field construction work.
Constructing states from sequences of observations is an important component of reinforcement learning agents. One solution for state construction is to use recurrent neural networks. Back-propagation through time (BPTT), and real-time recurrent learning (RTRL) are two popular gradient-based methods for recurrent learning. BPTT requires complete trajectories of observations before it can compute the gradients and is unsuitable for online updates. RTRL can do online updates but scales poorly to large networks. In this paper, we propose two constraints that make RTRL scalable. We show that by either decomposing the network into independent modules or learning the network in stages, we can make RTRL scale linearly with the number of parameters. Unlike prior scalable gradient estimation algorithms, such as UORO and Truncated-BPTT, our algorithms do not add noise or bias to the gradient estimate. Instead, they trade off the functional capacity of the network for computationally efficient learning. We demonstrate the effectiveness of our approach over Truncated-BPTT on a prediction benchmark inspired by animal learning and by doing policy evaluation of pre-trained policies for Atari 2600 games.