Instytut Lotnictwa

This study examines scientific and technical solutions designed to enhance thermodynamic processes in modern aircraft turbine engines by utilizing heat exchangers. A comprehensive literature review informed the development of a conceptual design for a turbofan engine incorporating both an intercooler and a recuperator. The research included an original parametric and constrained optimization analysis conducted for two engine configurations as follows: one intended for narrow-body and the other for wide-body aircraft. The study focused on achieving the required thrust while enhancing efficiency. Results indicate that integrating heat exchangers can significantly reduce specific fuel consumption (SFC) and/or increase engine power or thrust. Moreover, the recovery of residual heat from exhaust gases through recuperation contributes to improved overall energy efficiency. The study also explores a novel cryogenic design that utilizes liquid hydrogen for cooling the intercooler, recuperator, and turbine. Although not modeled directly, this concept demonstrates the potential to increase the bypass ratio, further reduce SFC, and lower NOx emissions. These findings highlight the promise of combined intercooling and recuperation strategies for improving both economic and environmental performance, with optimal system parameters dependent on aircraft class. The research aligns with ongoing efforts in mechanical engineering and aviation to enhance turbine engine efficiency through innovative thermal management solutions.

Flammability and smoke generation of glass-fiber-reinforced polyester laminates (GFRPs) modified with L-arginine phosphate (ArgPA) have been investigated. The composition, structure, and thermal degradation processes of ArgPA were assessed by the elemental, FTIR, and thermogravimetric analyses. Flammability and smoke emission of GFRPs varying by different amounts (5-15 wt.%) of bio-based flame retardant (FR) prepared via hand lay-up method were assessed in terms of the limiting oxygen index (LOI) and smoke density tests. It was observed that the addition of ArgPA results in the formation of a charred layer with visible bubbles. The LOI of GFRP with 15 wt.% of ArgPA increased from 20.73 V/V % (non-modified GFRP) to 24.55 V/V %, and the material classification was improved from combustible to self-extinguishing. FRs usually increase the specific optical density of smoke, which was also observed for ArgPA-modified GFRPs. However, the specific optical density of smoke at the 4th minute of measurement (Ds(4)) obtained for ArgPA-modified GFRPs was lower than for GFRPs modified with commercially used APP. TG/FTIR studies of resin modified with ArgPA revealed the presence of phosphorus compounds and non-combustible gases in the decomposition products. Results demonstrate the potential of ArgPA as an effective, bio-based FR for the enhancement of GFRP fire safety.

The development of hierarchical structures of unmanned aerial vehicles (UAVs) increases the efficiency of unmanned aerial systems. The grouping of UAVs increases the region of recognition or force of assault. Achieving these requirements is possible through a UAV formation. The UAVs in the formation must be controlled and managed by a commander, but the commander cannot control individual UAVs. The UAVs within the formation have assigned specific individual tasks, so is possible to achieve the flight of the formation with minimum collisions between UAVs and maximized equipment utilization. This paper aims to present a method of formation control for multiple UAVs that allows dynamic changes in the constellations of UAVs. The article includes the results of tests and research conducted in real-world conditions involving a formation capable of adapting its configuration. The results are presented as an element of research for the autonomy swarm, which can be controlled by one pilot/operator. The control of a swarm consisting of many UAVs (several hundred) by one person is now a current problem. The article presents a fragment of research work on high-autonomy UAV swarms. Here is presented a field test that focuses on UAV constellation control.

This article will discuss the software development process utilised in the GNSS-denied navigation project targeted for drones. The process was implemented in an environment where software developers were oriented to developing a source code only and who showed great reluctance to follow any formal process. The mentioned process was a lightweight AGILE-based process that, by assumption, minimised developers’ engagement in activities other than those related to the source code development. The process described in this paper was designed to support and reflect product quality characteristics like functional completeness and correctness, time behaviour, resource utilisation, analysability, modifiability and testability in an “implicit” way. It allowed the developers to achieve those characteristics in an “invisible” manner. This allowed us to achieve acceptable product quality without needing to engage experienced architects. The described process needs improvements and extensions to satisfy certification needs. However, for the prototyping or research phases, it may be a perfect solution for facilitating future product modifications and saving costs. The process improves product quality by underlying the value of transparency, performing specific actions and incorporating specific attributes related to team tasks. This research also focused on finding a metric related to process acceptance in a given environment, resulting in a three-degree scale showing whether the process needed improvements or was accepted by the environment. Such a metric is a new finding and the metric implies that there are some factors that stand behind any process, which determine whether it will be friendly to the environment (people with their habits, work style, personal traits, etc.) or not. However, investigating factors that determine the process acceptance and that are connected to the environment traits were beyond the scope of this research and will be considered in the future.

This review paper presents the current progress in the development of resistance welding techniques for thermoplastic composites, with a particular emphasis on their application in hybrid joints, such as those involving thermosetting composites and metals. Resistance welding, a fusion bonding method, offers significant advantages over adhesive bonding and mechanical joining by eliminating the need for additional adhesive materials and enabling integration into automated manufacturing processes. The study highlights the unique benefits of resistance welding, including lower energy consumption compared to other methods and its compatibility with automated manufacturing, which can reduce production costs by up to 40%. Key findings from the literature indicate that resistance welding is particularly effective in achieving strong, durable joints for complex and large structures, such as those used in the aerospace industry. The review also identifies the main challenges associated with resistance welding, including temperature control, current leakage in carbon-fiber-reinforced polymers, and potential corrosion when using metal meshes. To address these challenges, various strategies are discussed, including surface treatments, the use of nanocomposites, and the integration of carbon nanotubes. The review concludes by emphasizing the need for further research to optimize welding parameters and to develop non-destructive testing methods for industrial applications, ensuring the reliability and long-term performance of welded joints.

Colorectal cancer (CRC) is the second common cause of cancer mortality worldwide, and it still lacks effective approaches for relapsed and metastatic CRC. Recently, oncolytic virus has been emerged as a promising immune therapeutic strategy. In this study, we develop a novel oncolytic adenovirus, rAd.mDCN.mCD40L, which drive oncolytic activity by telomerase reverse transcriptase promoter (TERTp). rAd.mDCN.mCD40L expressed both mouse genes of decorin (mDCN) and CD40 ligand (mCD40L), and produced effective cytotoxicity in both human and mouse CRC cells. Moreover, oncolytic adenovirus mediated mDCN over-expression inhibited Met expression in vitro. In CT26 subcutaneous tumor model, intratumorally delivery of oncolytic adenoviruses could inhibit tumor growth and liver metastasis, while mDCN and/or mCD40L armed oncolytic adenoviruses produced much more impressive responses. No obvious toxicity was detected in lung, liver and spleen. Moreover, mDCN and/or mCD40L armed oncolytic adenoviruses altered the immune state to activate anti-tumor responses, including increasing CD8+ T effector cells and CD4+ memory T cells, reducing MDSCs and Tregs in peripheral blood. Furthermore, mDCN and/or mCD40L armed oncolytic adenoviruses mediated mDCN and/or mCD40L expression in tumors, and up-regulated Th1 cytokines and reduced Th2 cytokines in tumors, which will be benefit for remodeling tumor microenvironment. Importantly, rAd.mDCN.mCD40L and rAd.mCD40L prevented tumor liver metastasis much more effectively than rAd.Null and rAd.mDCN. Therefore, rAd.mDCN.mCD40L and rAd.mCD40L are promising approaches for CRC therapy.

In the present study, using a combination of theoretical discussions, practical examples, and case studies, we sought to gain a comprehensive understanding of how numerical solutions could be used to improve the design and optimize the thermal efficiency of a heat exchanger that utilizes wastewater to reduce the domestic consumption of hot water. To this end, we developed a validated numerical model. We also carried out simulations and experiments, the results of which are presented in this paper. The novelty of this work derives from our use of a new heat exchanger design for a domestic shower, and from the presented experimental–numerical evidence that proves its efficiency. We found that use of our newly designed appliance improved thermal efficiency from 14% to 27%. Moreover, we estimated that the cost of manufacturing and installing such a device did not exceed that of a widely available drain grid. Using our newly designed exchanger, a family of four living in Poland could save EUR 38 (at 2022 values) and reduce CO2 emissions by 192 kg. An average European family could save EUR 68 and reduce CO2 emissions by 76 kg.