Mimicking natural structures allows the exploitation of proven design concepts for advanced material solutions. Here, our inspiration comes from the anisotropic closed cell structure of wood. The bubbles in our fiber reinforced foam are elongated using temperature dependent viscosity of methylcellulose and constricted drying. The oriented structures lead to high yield stress in the primary direction; 64 times larger than compared to the cross direction. The closed cells of the foam also result in excellent thermal insulation. The proposed novel foam manufacturing process is trivial to up-scale from the laboratory trial scale towards production volumes on industrial scales.

This study deals with the synthesis and thorough characterization of the conjugated polymer T-EHPPD-T-EHBDT, which shows promising performance in polymer/non-fullerene acceptor organic solar cells.

Decarbonization of the automotive industry is one of the major challenges in the transportation sector, according to the recently proposed climate neutrality policies, e.g., the EU 'Fit for 55' package. Hydrogen as a carbon-free energy career is a promising alternative fuel to reduce greenhouse gas emissions. The main objective of the present study is to investigate non-reactive hydrogen jet impingement on a piston bowl profile at different injection angles and under the effect of various pressure ratios (PR), where PR is the relative ratio of injection pressure (IP) to chamber pressure (CP). This study helps to gain further insight into the mixture formation in a heavy-duty hydrogen engine, which is critical in predicting combustion efficiency. In the experimental campaign, a typical high-speed z-type Schlieren method is applied for visualizing the jet from the lateral windows of a constant volume chamber, and two custom codes are developed for postprocessing the results. In particular, the jet's major characteristics i.e., penetration, width, and cross-sectional area are calculated at different PRs (25, 10, 5, and 2.5). The results show that higher pressure ratios lead to faster penetration and larger cross-sectional areas of the hydrogen jet. In addition, the jet-piston interaction at different angles as well as the flow around the piston towards the liner and back to the main cylinder volume are studied considering the optimization of mixture formation in the cylinder. By changing the injection angle (10°, 15°, and 20°), jet-piston impingement occurs near the edges, which results in greater hydrogen concentration around those areas, adversely affecting mixture formation. The measurements are further used to validate a numerical model for hydrogen injection and mixing in a similar jet-piston geometry, applying an unsteady Reynoldsaveraged Navier-Stokes simulation approach in the commercial software Star-CCM+.

<div class="section abstract"><div class="htmlview paragraph">Hydrogen (H₂), a potential carbon-neutral fuel, has attracted considerable attention in the automotive industry for transition toward zero-emission. Since the H₂ jet dynamics play a significant role in the fuel/air mixing process of direct injection spark ignition (DISI) engines, the current study focuses on experimental and numerical investigation of a low-pressure H₂ jet to assess its mixing behavior. In the experimental campaign, high-speed z-type schlieren imaging is applied in a constant volume chamber and H₂ jet characteristics (penetration and cross-sectional area) are calculated by MATLAB and Python-based image post-processing. In addition, the Unsteady Reynolds-Averaged Navier-Stokes (URANS) approach is used in the commercial software Star-CCM+ for numerical simulations. The H₂ jet dynamics is investigated under the effect of nozzle geometry (single-hole, double-hole, and multiple-hole (5-hole)), which constitutes the novelty of the present research, and pressure ratio (PR = injection pressure (P_i) / chamber pressure (P_ch)). The results show that the H₂ jet from the single-hole nozzle possesses the fastest penetration and smallest cross-sectional area. On the contrary, the H₂ jet from the double-hole nozzle possesses the slowest penetration and largest cross-sectional area. The H₂ jet from the multiple-hole nozzle shows characteristics between those of the single-hole and double-hole. Overall, since higher pressure ratio and larger jet cross-sectional area lead to higher uniformity of the fuel/air mixture, high-pressure injection with the double-hole nozzle seems more advantageous to attain efficient mixing.</div></div>