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Design of Low-Energy Composites Based on Upcycled Construction Waste
Návrh nízkoenergetických kompozitů na bázi upcyklovaného stavebního odpadu
(Czech Technical University in Prague) Mildner, Martin; Fořt, Jan; Golian-Struhárová, Alena; Pokorný, Jaroslav; Litoš, Jiří
The dissertation focuses on analysing the potential of construction and demolition waste, particularly recycled brick material, for the design of innovative binders based on alkali-activated materials (AAM). The work provides new findings on the use and valorisation of waste streams through alkali activation, thereby supporting circularity in the construction sector and contributing to a reduction in waste generation. The introductory part summarises the current challenges in this field and outlines the main starting points for innovation in construction materials, including a reassessment of established approaches. The experimental part includes a detailed characterisation of the recycled brick material and its subsequent use, in combination with a by-product of metakaolin production (RON), for the design of AAM systems containing 50100% recycled brick component (OCR) and 050% RON. Both paste and mortar specimens were designed and characterised in terms of basic properties, rheology, microstructure, chemical composition, mechanical performance, durability, and environmental parameters. The results show that the use of multi-component precursors enables the material properties to be adjusted and allows waste or by-products to be converted into binders with performance comparable to conventional cement-based binders. Paste mixtures, 90-day compressive strengths in the range of around 1638.6 MPa were demonstrated. Mixtures with a medium to high RON content showed improved mechanical performance, a finer pore structure, and a higher share of amorphous phase. Life cycle assessment (LCA) indicated that the designed pastes achieve a substantial reduction in carbon footprint (by more than half) compared with a reference Portland cement. The main source of environmental impacts was identified as the alkaline activators, whereas the brick-based precursors contributed only to a limited extent. Mortar mixtures confirmed the beneficial effect of combining OCR and RON on both mechanical and durability performance. At 90 days, compressive strengths of approximately 2245.8 MPa were achieved, depending on the OCR/RON ratio. Very good resistance to freezethaw cycling (50 and 100 cycles) was demonstrated, with most mixtures showing only a minor strength decrease. The dissertation provides new knowledge on the upcycling of underutilised recycled brick material into value-added binders. By achieving synergistic effects through the use of the more reactive RON component, low-carbon composites can be designed with potential application across a wide range of construction products.
Life cycle assessment for informed decision-making in radon mitigation
(Elsevier, 2026) Felicioni L.; Jiránek M.; Lupíšek A.
Radon is the most common indoor air pollutant leading to harmful effects on public health and has been recognised as the second most frequent cause of lung cancer after smoking, accounting for approximately 10–15 % of cases attributable to radon exposure in buildings. This study presents the environmental impacts associated with various radon control technologies, encompassing both active and passive solutions applicable to both new constructions and pre-existing buildings. The assessment was conducted utilizing the Life Cycle Assessment (LCA) methodology, using a single-family house serving as a case study. A total of 11 preventive measures and 7 remedial measures were assessed to determine the most environmentally friendly solutions. The evaluation primarily considered the Global Warming Potential (GWP) over a 50-year service life and other 9 environmental categories commonly relevant to the construction industry normalised and weighted with the Environmental Footprint (EF 3.0) single score indicator method. The analysis presented is an important contribution to the growing body of knowledge in the field of radon mitigation, exploring its environmental impacts and carrying implications within the European and international context as decision-making support. Moreover, this study provides essential data to support informed decision-making by designers and policymakers, integrating environmental performance into the selection of radon mitigation technologies in line with whole-life carbon objectives.
Enhancing sampling-based planning with a library of paths
(Elsevier, 2026) Minařík M.; Vonásek V.; Pěnička R.
Path planning for 3D solid objects is a challenging problem, requiring a search in a six-dimensional configuration space, which is, nevertheless, essential in many robotic applications such as bin-picking and assembly. The commonly used sampling-based planners, such as Rapidly-exploring Random Trees, struggle with narrow passages where the sampling probability is low, increasing the time needed to find a solution. In scenarios like robotic bin-picking, various objects must be transported through the same environment. However, traditional planners start from scratch each time, losing valuable information gained during the planning process. We address this by using a library of past solutions, allowing the reuse of previous experiences even when planning for a new, previously unseen object. Paths for a set of objects are stored, and when planning for a new object, we find the most similar one in the library and use its paths as approximate solutions, adjusting for possible mutual transformations. The configuration space is then sampled along the approximate paths. Our method is tested in various narrow passage scenarios and compared with state-of-the-art methods from the OMPL library. Results show significant speed improvements (up to 85% decrease in the required time) of our method, often finding a solution in cases where the other planners fail. Our implementation of the proposed method is released as an open-source package.
Autonomous Drone Racing: A Survey
(IEEE Robotics and Automation Society, 2024) Hanover D.; Loquercio A.; Bauersfeld L.; Romero A.; Song Y.; Cioffi G.; Kaufmann E.; Scaramuzza D.; Pěnička R.
Over the last decade, the use of autonomous drone systems for surveying, search and rescue, or last-mile delivery has increased exponentially. With the rise of these applications comes the need for highly robust, safety-critical algorithms that can operate drones in complex and uncertain environments. Additionally, flying fast enables drones to cover more ground, increasing productivity and further strengthening their use case. One proxy for developing algorithms used in high-speed navigation is the task of autonomous drone racing, where researchers program drones to fly through a sequence of gates and avoid obstacles as quickly as possible using onboard sensors and limited computational power. Speeds and accelerations exceed over 80 kph and 4 g, respectively, raising significant challenges across perception, planning, control, and state estimation. To achieve maximum performance, systems require real-time algorithms that are robust to motion blur, high dynamic range, model uncertainties, aerodynamic disturbances, and often unpredictable opponents. This survey covers the progression of autonomous drone racing across model-based and learning-based approaches. We provide an overview of the field, its evolution over the years, and conclude with the biggest challenges and open questions to be faced in the future.
MRS Drone: A Modular Platform for Real-World Deployment of Aerial Multi-Robot Systems
(Kluwer Academic Publishers, 2023) Štěpán P.; Walter V.; Heřt D.; Báča T.; Petráček P.; Krátký V.; Pěnička R.; Spurný V.; Petrlík M.; Vrba M.; Žaitlík D.; Stoudek P.; Horyna J.; Pritzl V.; Šrámek M.; Ahmad A.; Silano G.; Bonilla Licea D.; Štibinger P.; Pereira do Nascimento T.; Saska M.
This paper presents a modular autonomous Unmanned Aerial Vehicle (UAV) platform called the Multi-robot System (MRS) Drone that can be used in a large range of indoor and outdoor applications. The MRS Drone features unique modularity changes in actuators, frames, and sensory configuration. As the name suggests, the platform is specially tailored for deployment within a MRS group. The MRS Drone contributes to the state-of-the-art of UAV platforms by allowing smooth real-world deployment of multiple aerial robots, as well as by outperforming other platforms with its modularity. For real-world multi-robot deployment in various applications, the platform is easy to both assemble and modify. Moreover, it is accompanied by a realistic simulator to enable safe pre-flight testing and a smooth transition to complex real-world experiments. In this manuscript, we present mechanical and electrical designs, software architecture, and technical specifications to build a fully autonomous multi UAV system. Finally, we demonstrate the full capabilities and the unique modularity of the MRS Drone in various real-world applications that required a diverse range of platform configurations.