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The internal structure of a material is crucial in the design of a number of components, especially those that carry significant loads. Also, the design of such 3D printed components should take into account the type of internal structure of a printed piece. The aim of the study was to evaluate the influence of an internal structure (degree of filling and printing direction) of a 3D printed component on its selected mechanical properties. To carry out experimental research, a set of PLA filament samples was prepared using 3D printing, using a MakerBot Replicator Z18 printer. The test pieces were manufactured in both longitudinal and transverse printing; both the longitudinal and transverse printing were made in two positionings: plane and edge. In this case, four different internal structures were obtained from which static tensile strength and impact tests were carried out. In addition, the samples were made with three different filling options: 100%, 70% and 30%. As a result of the research, it was found that the strength of elements produced by 3D printing from PLA is higher if they are printed in an edge formula, which means that the speed of applying subsequent layers probably plays an important role in building strength.

In the modern aerospace industry, a steady increase in the share of composite materials is recorded every single year. Polymer layer composites seem to be the ones that are used most commonly in aviation. There are multiple methods of producing this type of materials, of which the most commonly used methods are as follows: the infusion method, the negative pressure bag method and the hydraulic press method. The infusion process makes it possible to obtain composites with the best mechanical properties. In the infusion process, the mould is pre-prepared (together with the reinforcement made of the material from which the composite is made, e.g. carbon fibre), which is tightly closed in a negative pressure bag, and the equipment supplying the previously mixed resin with hardener is connected to the injection points. The negative pressure generated by the negative pressure pump in the mould prepared in this way (negative pressure bag) makes the previously prepared resin seep through the reinforcement material. Various negative pressure levels can be used. This work describes the effect of the applied negative pressure level on the obtained mechanical properties of a composite reinforced with carbon fibres. It appears that the best visual properties of the composite material are obtained with the use of indirect (optimal) negative pressure but the best strength properties with the use of maximal negative pressure.

Rare earth elements are an essential critical raw material in the development of modern technologies and are highly sensitive to both supply chain disruptions and market turbulence. The presented study examines the characteristics of fuel, fly ash, and bottom ash from lignite combustion in power plant units. Also, we attempted to determine the amount of amorphous glass in the ashes and whether and to what extent the glass from the ash samples is bound to REY. The suitability of the ash was assessed as an alternative source of REY. The fuel and ash samples were acquired from power plants in Poland. The tests determined the fuel quality parameters, including the chemical and phase composition, of amorphous glass using ICP-MS and XRD methods, respectively. The study showed that all ash samples dissolved in 4% HF were enriched in REY. The efficiency of REY enrichment varied, and its presence in the residue samples was found to be in similar proportions compared to the raw sample. All ash residue samples were enriched in critical elements. The obtained values of the Coutl prospective coefficient allowed for the classification of some of the analyzed ashes and their residues after dissolution in 4% HF as prospective REY raw materials.

IntroductionInterpersonal synchronization involves the alignment of behavioral, affective, physiological, and brain states during social interactions. It facilitates empathy, emotion regulation, and prosocial commitment. Mental disorders characterized by social interaction dysfunction, such as Autism Spectrum Disorder (ASD), Reactive Attachment Disorder (RAD), and Social Anxiety Disorder (SAD), often exhibit atypical synchronization with others across multiple levels. With the introduction of the “second-person” neuroscience perspective, our understanding of interpersonal neural synchronization (INS) has improved, however, so far, it has hardly impacted the development of novel therapeutic interventions.MethodsTo evaluate the potential of INS-based treatments for mental disorders, we performed two systematic literature searches identifying studies that directly target INS through neurofeedback (12 publications; 9 independent studies) or brain stimulation techniques (7 studies), following PRISMA guidelines. In addition, we narratively review indirect INS manipulations through behavioral, biofeedback, or hormonal interventions. We discuss the potential of such treatments for ASD, RAD, and SAD and using a systematic database search assess the acceptability of neurofeedback (4 studies) and neurostimulation (4 studies) in patients with social dysfunction.ResultsAlthough behavioral approaches, such as engaging in eye contact or cooperative actions, have been shown to be associated with increased INS, little is known about potential long-term consequences of such interventions. Few proof-of-concept studies have utilized brain stimulation techniques, like transcranial direct current stimulation or INS-based neurofeedback, showing feasibility and preliminary evidence that such interventions can boost behavioral synchrony and social connectedness. Yet, optimal brain stimulation protocols and neurofeedback parameters are still undefined. For ASD, RAD, or SAD, so far no randomized controlled trial has proven the efficacy of direct INS-based intervention techniques, although in general brain stimulation and neurofeedback methods seem to be well accepted in these patient groups.DiscussionSignificant work remains to translate INS-based manipulations into effective treatments for social interaction disorders. Future research should focus on mechanistic insights into INS, technological advancements, and rigorous design standards. Furthermore, it will be key to compare interventions directly targeting INS to those targeting other modalities of synchrony as well as to define optimal target dyads and target synchrony states in clinical interventions.

The aim of the research was to assess the potential of bottom ash from Polish coal-fired power plants as an alternative source of rare earth elements (REY). The potential of these ashes was compared with fly ash from the same coal combustion cycle. The phase and chemical composition, as well as REY, were determined using: X-ray diffraction and inductively coupled plasma mass spectrometry. The tested ashes were classified as inert-low pozzolanic and inert-medium pozzolanic, as well as sialic and ferrosialic, with enrichment in detrital material. The phase and chemical composition of bottom ash was similar to fly ash from the same fuel combustion cycle. The REY content in the ash was 199–286 ppm and was lower than the average for global deposits, and the threshold value was considered profitable for recovery from coal. Bottom ash’s importance as a potential source of REY will increase by recovering these metals from separated amorphous glass and mullite and grains rich in Al, Mg, K, and P. The industrial value of bottom ash as an alternative source of REY was similar to fly ash from the same fuel combustion cycle.

The ongoing scientific debate on the selection of the best bioindicators to reflect the quality of arable soils indicates both their microbiome and biochemical parameters. Consideration has also been given to the fact that Zea mays has achieved the status of a crop used in the feed industry and for energy purposes, and Triticosecale is attracting increasing interest in this area. Therefore, the aim of this study was to determine the wide range of effects of Zea mays and Triticosecale cultivation on soil microbial and biochemical activity. The assessment of these parameters was based on the determination of microbial abundance, colony development index (CD), ecophysiological index of microbial diversity (EP), soil enzyme activities (dehydrogenases, catalase, urease, acid phosphatase, alkaline phosphatase, β-glucosidase, and arylsulfatase) as well as soil physicochemical properties. The innovative nature of the research was achieved by extending the pool of analyses to include both microbial biodiversity and analysis of soil samples at three depths: 0–20 cm; 21–40 cm; and 41–60 cm. It was found that the highest activities of soil enzymes and the abundance of organotrophic bacteria and fungi, as well as their colony development indices (CD), occurred within the rhizosphere and that their values decreased with increasing depth of the soil profile layers. Two phyla, Actinobacteria and Proteobacteria, representing the microbiome of arable soils, were identified independently of soil management practices. Unique bacterial genera in the soil under Triticosecale cultivation were Pseudonocardia, whereas Rhodoplanes, Nocardioides, and Rhodanobacter were found under Zea mays cultivation. The activity of all enzymes, especially urease and arylsulfatase, was significantly higher in the soil under Triticosecale. This was influenced by the more favorable physicochemical properties of the soil.

Fibre-metal laminates combine both the properties of metal and composite materials, reinforced with fibres; first such laminates already appeared at the end of the 70s. Alongside with the emergence of spacecraft, in which the external plating heats up to temperatures even exceeding 3000 °C, there was a demand for new materials, with increased thermal resistance. Moreover, high thermal resistance is also required in the construction of different protective casings for sensitive equipment, e.g. flight data recorders. In order to protect a spacecraft from massive amounts of heat This article presents research findings, aimed at determining the influence of including metal reinforcement in the form of steel sheet upon the thermal resistance of a multi-layered polymer composite. The samples were exposed to a mixture of hot gases at a temperature of over 900 °C for a period of approximately 150 s. The most important parameter determined on the basis of experimental research was the temperature of the rear surface of the sample. It was observed, that the addition of metal reinforcement causes stabilization of the temperature of the back wall of the sample and a decrease in temperature of the rear wall surface of the insulating sample by approximately 45% and approximately 2-fold increase in the ablative mass loss.

We present synchrotron-based mass spectrometry to probe products formed in a lithium sulphide electrolyte. In operando analysis was carried out at two different potentials in a vacuum compatible microfluidic electrochemical cell. Mass spectral observations show that the charged electrolyte formed sulphur clusters under dynamic conditions, demonstrating electrolyte electron shuttling.

Abstract Background The detrimental impact of malnutrition and cachexia in cancer patients subjected to surgical resection is well established. However, how systemic and local metabolic alterations in cancer patients impact the serum metabolite signature, thereby leading to cancer‐specific differences, is poorly defined. In order to implement metabolomics as a potential tool in clinical diagnostics and disease follow‐up, targeted metabolite profiling based on quantitative measurements is essential. We hypothesized that the quantitative metabolic profile assessed by 1H nuclear magnetic resonance (NMR) spectroscopy can be used to identify cancer‐induced catabolism and potentially distinguish between specific tumour entities. Importantly, to prove tumour dependency and assess metabolic normalization, we additionally analysed the metabolome of patients' sera longitudinally post‐surgery in order to assess metabolic normalization. Methods Forty two metabolites in sera of patients with tumour entities known to cause malnutrition and cachexia, namely, upper gastrointestinal cancer and pancreatic cancer, as well as sera of healthy controls, were quantified by 1H NMR spectroscopy. Results Comparing serum metabolites of patients with gastrointestinal cancer with healthy controls and pancreatic cancer patients, we identified at least 15 significantly changed metabolites in each comparison. Principal component and pathway analysis tools showed a catabolic signature in preoperative upper gastrointestinal cancer patients. The most specifically upregulated metabolite group in gastrointestinal cancer patients was ketone bodies (3‐hydroxybutyrate, P

Rare earth elements are an essential critical raw material in the development of modern technologies and are highly sensitive to both supply chain disruptions and market turbulence. The presented study examines the characteristics of fuel, fly ash, and bottom ash from lignite combustion in power plant units. Also, we attempted to determine the amount of amorphous glass in the ashes and whether and to what extent the glass from the ash samples is bound to REY. The suitability of the ash was assessed as an alternative source of REY. The fuel and ash samples were acquired from power plants in Poland. The tests determined the fuel quality parameters, including the chemical and phase composition, of amorphous glass using ICP-MS and XRD methods, respectively. The study showed that all ash samples dissolved in 4% HF were enriched in REY. The efficiency of REY enrichment varied, and its presence in the residue samples was found to be in similar proportions compared to the raw sample. All ash residue samples were enriched in critical elements. The obtained values of the Coutl prospective coefficient allowed for the classification of some of the analyzed ashes and their residues after dissolution in 4% HF as prospective REY raw materials. [ABSTRACT FROM AUTHOR]

The aim of the research was to assess the potential of bottom ash from Polish coal-fired power plants as an alternative source of rare earth elements (REY). The potential of these ashes was compared with fly ash from the same coal combustion cycle. The phase and chemical composition, as well as REY, were determined using: X-ray diffraction and inductively coupled plasma mass spectrometry. The tested ashes were classified as inert-low pozzolanic and inert-medium pozzolanic, as well as sialic and ferrosialic, with enrichment in detrital material. The phase and chemical composition of bottom ash was similar to fly ash from the same fuel combustion cycle. The REY content in the ash was 199–286 ppm and was lower than the average for global deposits, and the threshold value was considered profitable for recovery from coal. Bottom ash's importance as a potential source of REY will increase by recovering these metals from separated amorphous glass and mullite and grains rich in Al, Mg, K, and P. The industrial value of bottom ash as an alternative source of REY was similar to fly ash from the same fuel combustion cycle. [ABSTRACT FROM AUTHOR]

Vacuum ultraviolet (VUV) single photon ionization mass spectrometry (SPI-MS) is a vacuum-based technique typically used for the analysis of gas phase and solid samples, but not for liquids due to the challenge in introducing volatile liquids in a vacuum. Here we present the first demonstration of in situ liquid analysis by integrating the System for Analysis at the Liquid Vacuum Interface (SALVI) microfluidic reactor into VUV SPI-MS. Four representative volatile organic compound (VOC) solutions were used to illustrate the feasibility of liquid analysis. Our results show the accurate mass identification of the VOC molecules and the reliable determination of appearance energy that is consistent with ionization energy for gaseous species in the literature as reported. This work validates that the vacuum-compatible SALVI microfluidic interface can be utilized at the synchrotron beamline and enable the in situ study of gas-phase molecules evaporating off the surface of a liquid, which holds importance in the study of condensed matter chemistry.

Construction adhesives are usually polymers that have been modified to achieve specific properties so that they can be used under various loading conditions. An attempt was made to estimate the effect of fatigue loading on the temperature of an adhesive material by further physically modifying the basic adhesive composition used in the research. The temperature of the materials during the tests was recorded using a thermal imaging camera and a thermoelectric thermometer. For most materials tested at 20 Hz, an increase in the number of load cycles corresponded to an increase in the temperature of the samples. For a frequency of 30 Hz, after the temperature increased by a certain value, the temperature of the modified samples recorded with the thermal imaging camera decreased. Fatigue loading caused an increase of the temperature of all tested polymeric materials. Observation of the sample during testing with a thermal imaging camera allows a simple identification of the areas with the highest temperature and can be much more useful in practice than recording temperatures with a thermocouple thermometer, as thermocouples need to be properly positioned before testing.

An attempt was made to estimate the value of the deformation energy of a metal specimen and the research system during impact strength tests on pendulum hammers. In the experimental research it was found that the rectangular metal specimens of the same cross-sectional area demonstrate different impact strength, depending on the direction of the load (bending stiffness) whereas the destruction work of such samples exposed to static bending is comparable. The article presents the results of the experimental research, completed with numerical calculations carried out to assess the value of the deformation energy during the impact tests. By performing numerical calculations, the authors estimated the deformation energies of specimens characterised by elastoplastic properties with a reinforcement (bilinear) under destructive loads. The energy of the elastic deformation of the hammer arm was estimated analytically. Based on the research, it was found that in the impact strength test, a large part of the recorded energy is connected with the deformation of the test device, in particular, the pendulum which undergoes bending. Also the recorded impact strength of the material is not proportional to its actual impact strength.

GoalThis paper presents an immersive Virtual Reality (VR) system to analyze and train Executive Functions (EFs) of soccer players. EFs are important cognitive functions for athletes. They are a relevant quality that distinguishes amateurs from professionals.MethodThe system is based on immersive technology, hence, the user interacts naturally and experiences a training session in a virtual world. The proposed system has a modular design supporting the extension of various so-called game modes. Game modes combine selected game mechanics with specific simulation content to target particular training aspects. The system architecture decouples selection/parameterization and analysis of training sessions via a coaching app from an Unity3D-based VR simulation core. Monitoring of user performance and progress is recorded by a database that sends the necessary feedback to the coaching app for analysis.ResultsThe system is tested for VR-critical performance criteria to reveal the usefulness of a new interaction paradigm in the cognitive training and analysis of EFs. Subjective ratings for overall usability show that the design as VR application enhances the user experience compared to a traditional desktop app; whereas the new, unfamiliar interaction paradigm does not negatively impact the effort for using the application.ConclusionThe system can provide immersive training of EF in a fully virtual environment, eliminating potential distraction. It further provides an easy-to-use analyzes tool to compare user but also an automatic, adaptive training mode.

The growing demand for rare-earth elements and yttrium (REY) in modern technologies has resulted in the systematic depletion of primary ores. For this reason, research is being conducted around the world on alternative sources of rare-earth elements, e.g., on the possibilities of recovering REY from coal waste or coal combustion. The article presents the results of comprehensive tests of the fuel—hard coal, and high-temperature HTA ash, fly ash, and bottom ash. Examined samples were taken from a Polish power plant. In the tests, fuel quality parameters were determined in accordance with the standards; microscopic observations in reflected and transmitted light, as well as a scanning electron microscope (SEM/EDS), were used, and chemical and phase composition were determined using ICP-MS and XRD methods, respectively. The distribution of REY between these ashes was analyzed. Their suitability as alternative sources of REY was assessed. The obtained results showed that the process of hard coal combustion in pulverized coal boilers influenced the geochemical differentiation of REY elements in energy waste. This differentiation is manifested by higher concentrations of REY and critical elements in the fly ash than in the bottom ash. The obtained values of the Coutl prospective coefficient made it possible to classify the analyzed fly and bottom ashes as prospective REY raw materials.

The ongoing scientific debate on the selection of the best bioindicators to reflect the quality of arable soils indicates both their microbiome and biochemical parameters. Consideration has also been given to the fact that Zea mays has achieved the status of a crop used in the feed industry and for energy purposes, and Triticosecale is attracting increasing interest in this area. Therefore, the aim of this study was to determine the wide range of effects of Zea mays and Triticosecale cultivation on soil microbial and biochemical activity. The assessment of these parameters was based on the determination of microbial abundance, colony development index (CD), ecophysiological index of microbial diversity (EP), soil enzyme activities (dehydrogenases, catalase, urease, acid phosphatase, alkaline phosphatase, β-glucosidase, and arylsulfatase) as well as soil physicochemical properties. The innovative nature of the research was achieved by extending the pool of analyses to include both microbial biodiversity and analysis of soil samples at three depths: 0–20 cm; 21–40 cm; and 41–60 cm. It was found that the highest activities of soil enzymes and the abundance of organotrophic bacteria and fungi, as well as their colony development indices (CD), occurred within the rhizosphere and that their values decreased with increasing depth of the soil profile layers. Two phyla, Actinobacteria and Proteobacteria, representing the microbiome of arable soils, were identified independently of soil management practices. Unique bacterial genera in the soil under Triticosecale cultivation were Pseudonocardia, whereas Rhodoplanes, Nocardioides, and Rhodanobacter were found under Zea mays cultivation. The activity of all enzymes, especially urease and arylsulfatase, was significantly higher in the soil under Triticosecale. This was influenced by the more favorable physicochemical properties of the soil. [ABSTRACT FROM AUTHOR]

Coal gasification experiments were carried out in a reactor used to simulate underground coal gasification (UCG) processes under ex situ conditions at pressures of 10 and 40 bar. Changes in the optical properties of the organic matter were analyzed and the influence of temperature on coal during the UGC process was subsequently determined. The values of the true maximum reflectance determined for the gasification residue at pressures of 10 and 40 bar, and at distances of 0.75 and 1.75 m, reached a level corresponding to semi-graphite. Furthermore, it was found that the values of the true maximum reflectance and bireflectance decrease with increasing distance from the reactor chamber inlet. In addition, the results show that, regardless of the pressure used during the experiment, the temperature influence on the coal decreased with increasing distance from the reactor chamber inlet. The true temperatures operating during the experiment were higher than those recorded by the thermocouples, regardless of the pressure used. However, it was found that the distance at which the influence of temperature on the coal is still marked during the gasification process depends on the pressure used in the experiment. For example, in the case of the experiment at a pressure of 10 bar, the estimated distance is approximately 60 m, while for a pressure of 40 bar, it is approximately 35 m. These results can, and should, be taken into account for the planning of an UGC process.

Unburned carbon from fly ash and its graphitization products (at temperatures of 2400 and 3000°C) were tested using scanning electron microscope (SEM), X-ray diffraction (×RD) and micro-Raman spectroscopy. The same tests were also carried out for synthetic and natural graphite. Various morphological forms of products with a high degree of graphitization, such as spheroidal graphite, hexagonal plates, column plates, and jagged-edge films were identified in the sample of unburned carbon annealed at 3000°C. The product of thermal treatment at the temperature of 3000°C has the interlayer spacing d002 value characteristic for semigraphite. With increasing temperature the number of crystallites in stack N, their height Lc002 and aromaticity fa increases. The degree of G graphitization of annealed samples increases more than twice with increasing temperature. With the increase of the temperature the aliphatic chains are decomposed and the aromatic systems are reconstructed, so the degree of internal structure order increases. The Raman examinations showed that the structural parameters determined for the graphite and carbonizate samples after thermal treatment at the temperature of 3000°C are equal in the standard deviation range. [ABSTRACT FROM AUTHOR]

Introduction: Interpersonal synchronization involves the alignment of behavioral, affective, physiological, and brain states during social interactions. It facilitates empathy, emotion regulation, and prosocial commitment. Mental disorders characterized by social interaction dysfunction, such as Autism Spectrum Disorder (ASD), Reactive Attachment Disorder (RAD), and Social Anxiety Disorder (SAD), often exhibit atypical synchronization with others across multiple levels. With the introduction of the "second-person" neuroscience perspective, our understanding of interpersonal neural synchronization (INS) has improved, however, so far, it has hardly impacted the development of novel therapeutic interventions. Methods: To evaluate the potential of INS-based treatments for mental disorders, we performed two systematic literature searches identifying studies that directly target INS through neurofeedback (12 publications; 9 independent studies) or brain stimulation techniques (7 studies), following PRISMA guidelines. In addition, we narratively review indirect INS manipulations through behavioral, biofeedback, or hormonal interventions. We discuss the potential of such treatments for ASD, RAD, and SAD and using a systematic database search assess the acceptability of neurofeedback (4 studies) and neurostimulation (4 studies) in patients with social dysfunction. Results: Although behavioral approaches, such as engaging in eye contact or cooperative actions, have been shown to be associated with increased INS, little is known about potential long-term consequences of such interventions. Few proof-of-concept studies have utilized brain stimulation techniques, like transcranial direct current stimulation or INS-based neurofeedback, showing feasibility and preliminary evidence that such interventions can boost behavioral synchrony and social connectedness. Yet, optimal brain stimulation protocols and neurofeedback parameters are still undefined. For ASD, RAD, or SAD, so far no randomized controlled trial has proven the efficacy of direct INS-based intervention techniques, although in general brain stimulation and neurofeedback methods seem to be well accepted in these patient groups. Discussion: Significant work remains to translate INS-based manipulations into effective treatments for social interaction disorders. Future research should focus on mechanistic insights into INS, technological advancements, and rigorous design standards. Furthermore, it will be key to compare interventions directly targeting INS to those targeting other modalities of synchrony as well as to define optimal target dyads and target synchrony states in clinical interventions. [ABSTRACT FROM AUTHOR]

The significant growth of Additive Manufacturing (AM), visible over the last ten years, has driven an increase in demand for small gradation metallic powders of a size lower than 100 µm. Until now, most affordable powders for AM have been produced using gas atomization. Recently, a new, alternative method of powder production based on ultrasonic atomization with melting by electric arc has appeared. This paper summarizes the preliminary research results of AM samples made of two AISI 316L steel powder batches, one of which was obtained during Ultrasonic Atomization (UA) and the other during Plasma Arc Gas Atomization (PAGA). The comparison starts from powder particle statistical distribution, chemical composition analysis, density, and flowability measurements. After powder analysis, test samples were produced using AM to observe the differences in microstructure, porosity, and hardness. Finally, the test campaign covered an analysis of mechanical properties, including tensile testing with Digital Image Correlation (DIC) and Charpy’s impact tests. A comparative study of parts made of ultrasonic and gas atomization powders confirms the likelihood that both methods can deliver material of similar properties.

(1) Background: Due to the limitations of composite cements, the authors carried out tests to compare such materials with preheated composite materials because the latter may be an alternative to cements in the adhesive cementation procedure. (2) Methods: The materials used in the adhesive cementation procedure, i.e., Enamel Plus Hri (Micerium, Avegno, Italy), a heated composite material, and RelyX U200 Automix (3M, Maplewood, MN, USA), a dual composite cement, were tested for microhardness, compressive strength, flexural strength, diametral compressive strength, and elastic modulus. Composite material was heated to the temperature of 50 degrees Celsius before polymerisation. (3) Results: Higher values of microhardness (by 67.36%), compressive strength (by 41.84%), elastic modulus (by 17.75%), flexural strength (by 36.03%), and diametral compressive strength (by 45.52%) were obtained using the Enamel Plus Hri composite material compared to the RelyX U200 self-adhesive cement. The survey results revealed statistically significant differences. (4) Conclusions: Due to its better mechanical properties, the heated composite material (Enamel Plus Hri) is a beneficial alternative to composite cements in the indirect restoration placement procedure. As the strength parameters of the heated composite material increase, a higher resistance to the compressive and bending forces present in the oral cavity, and hence a greater durability of the created prosthetic reconstructions can be expected.

Den vielen außerschulischen Lernorten an der norddeut-schen Wattenmeerküste mangelt es in ihren Bildungsangeboten an Erklärungen und Modellen, die sich eignen, um auch die dortige physikalische Dynamik in Form von Strömungs- und Strukturbildungsphänomenen zu erklären. Die Lernort-leitenden berichten, dass Besuchende Fragen zu entsprechenden Phänomenen stellen, die weder von ihnen noch den Bildungsangeboten beantwortet werden können. Die vorliegende Studie widmet sich diesem Defizit. Sie ist in einem übergeordneten Projekt angesiedelt, das von der Deutschen Bundesstiftung Umwelt gefördert wird. Das übergeordnete DBU-Projekt zielt darauf ab, Exponate für außerschulische Lernorte zu entwickeln, die auch die physikalische Sicht auf die Dynamik an der Küste repräsentieren. Die vorliegende Studie leistet zu diesem übergeordneten Projekt insofern einen Beitrag, als eine Didaktische Rekonstruktion der physikalischen Dynamik an der Küste durchgeführt wurde, die darauf abzielte, Leitlinien für eine didaktische Strukturierung zu entwickeln. Um dieses Ziel zu erreichen, wurde im Rahmen der Didaktischen Rekonstruktion zunächst fachliche Klärung betrieben, indem die zentralen physikalischen Grundideen des Themenfelds herausgearbeitet wurden. Im zweiten Schritt wurden Lernendenperspektiven auf Strömungen und Strukturbildungen mit einer Interviewstudie erfasst. Dabei wurde zum einen beforscht, welche Merkmale Lernende mit den beiden Termini „Strömung“ und „Strukturbildung“ assoziieren. Zum anderen wurde untersucht, wie Lernende die Entstehung von Strömungen und Strukturbildungen erklären. Im dritten Schritt wurden die physikalischen Grundideen mit den untersuchten Lernendenperspektiven verglichen. Auf Basis dieses Vergleichs wurden Leitlinien für eine didaktische Strukturierung zur physikalischen Dynamik an der Küste erarbeitet. Diese Leitlinien dienen im übergeordneten DBU-Projekt der Unterstützung der Zusammenarbeit zwischen Physikdidaktik, Lernortleitenden und Ausstellungsagenturen zur Entwicklung neuer Ausstellungsexponate.

Composite materials are widely used in the construction of means of transport. Due to their low density and high stiffness, sandwich composites generate significant interest. The authors conducted static and dynamic tests in order to determine the effect of density and core thickness on the mechanical properties of a sandwich composite. Particular attention was paid to the impact properties of such composites. Herex and Airex polymer foams of different densities were used as cores, whereas the faces were made up of two layers of fabrics: glass and carbon. The matrix base of the tested materials was made of epoxy resin cured with a dedicated hardener. As a result of the study, a significant influence of the core on the strength parameters of the tested spacer materials was found. The examined polymer foams were found to have different adhesive properties, which affected their residual strength after an impact and the nature of destruction of the studied composites. It was observed that sandwich composites with a thicker core of higher density have higher impact strength and resistance to puncture. In the sandwich composites, low-energy impact loads result in damage only to the layer to which the load has been applied and has a core, so repairing such an element is much easier than in classic layered composites without a core. What is very important is that, in contrast to classic laminates, the bottom cover of the composite is not destroyed at low-impact energy values.