Main Achievements of the Rocket Technology Flight Experiment ROTEX-T

Based on experience gathered during the hypersonic flight experiments SHEFEX-I and SHEFEX-II the German Aerospace Center (DLR) performed the extensively instrumented flight experiment ROTEX-T (ROcket Technology EXperiment-Transition). ROTEX-T was successfully launched on 19th July 2016 at 06:05 am CEST from the Esrange Space Center near Kiruna in northern Sweden. Students of the RWTH Aachen University supported the design of the project with numerical simulations. ROTEX-T was a low cost flight experiment mission without inertial measurement unit, reaction control and parachute system. The payload reached an altitude of 183 kilometers, performed a ballistic re-entry with a total flight time of approximately 446 seconds and was afterwards recovered by helicopter. An unique and modular data acquisition system with sampling rates of 20 Hz, 1 kHz, 10 kHz and 2000 kHz was developed for ROTEX-T to study also instationary aerothermal phenomena

Fabrication and biomechanical characterization of a spider silk reinforced fibrin-based vascular prosthesis

With fibrin-based vascular prostheses, vascular tissue engineering offers a promising approach for the fabrication of biologically active regenerative vascular grafts. As a potentially autologous biomaterial, fibrin exhibits excellent hemo- and biocompatibility. However, the major problem in the use of fibrin constructs in vascular tissue engineering, which has so far prevented their widespread clinical application, is the insufficient biomechanical stability of unprocessed fibrin matrices. In this proof-of-concept study, we investigated to what extent the addition of a spider silk network into the wall structure of fibrin-based vascular prostheses leads to an increase in biomechanical stability and an improvement in the biomimetic elastic behavior of the grafts. For the fabrication of hybrid prostheses composed of fibrin and spider silk, a statically cast tubular fibrin matrix was surrounded with an envelope layer of Trichonephila edulis silk using a custom built coiling machine. The fibrin matrix was then compacted and pressed into the spider silk network by transluminal balloon compression. This manufacturing process resulted in a hybrid prosthesis with a luminal diameter of 4 mm. Biomechanical characterization revealed a significant increase in biomechanical stability of spider silk reinforced grafts compared to exclusively compacted fibrin segments with a mean burst pressure of 362 ± 74 mmHg vs. 213 ± 14 mmHg (p < 0.05). Dynamic elastic behavior of the spider silk reinforced grafts was similar to native arteries. In addition, the coiling with spider silk allowed a significant increase in suture retention strength and resistance to external compression without compromising the endothelialization capacity of the grafts. Thus, spider silk reinforcement using the abluminal coiling technique represents an efficient and reproducible technique to optimize the biomechanical behavior of small-diameter fibrin-based vascular grafts

Chemically induced hypoxia by dimethyloxalylglycine (dmog)-loaded nanoporous silica nanoparticles supports endothelial tube formation by sustained vegf release from adipose tissue-derived stem cells

Inadequate vascularization leading to insufficient oxygen and nutrient supply in deeper layers of bioartificial tissues remains a limitation in current tissue engineering approaches to which prevascularization offers a promising solution. Hypoxia triggering pre-vascularization by enhanced vascular endothelial growth factor (VEGF) expression can be induced chemically by dimethyloxalylglycine (DMOG). Nanoporous silica nanoparticles (NPSNPs, or mesoporous silica nanoparticles, MSNs) enable sustained delivery of molecules and potentially release DMOG allowing a durable capillarization of a construct. Here we evaluated the effects of soluble DMOG and DMOG-loaded NPSNPs on VEGF secretion of adipose tissue-derived stem cells (ASC) and on tube formation by human umbilical vein endothelial cells (HUVEC)-ASC co-cultures. Repeated doses of 100 mM and 500 mM soluble DMOG on ASC resulted in 3- to 7-fold increased VEGF levels on day 9 (P<0.0001). Same doses of DMOG-NPSNPs enhanced VEGF secretion 7.7-fold (P<0.0001) which could be maintained until day 12 with 500 mM DMOG-NPSNPs. In fibrin-based tube formation assays, 100 mM DMOG-NPSNPs had inhibitory effects whereas 50 mM significantly increased tube length, area and number of junctions transiently for 4 days. Thus, DMOG-NPSNPs supported endothelial tube formation by upregulated VEGF secretion from ASC and thus display a promising tool for prevascularization of tissue-engineered constructs. Further studies will evaluate their effect in hydrogels under perfusion

Objectives and Achievements of the Hypersonic Flight Experiment STORT

The three-stage rocket configuration of the hypersonic experiment STORT with several scientific payloads concerning hypersonic technologies was launched from the Andøya Space launch site in northern Norway on 26th June 2026 successfully. The third stage performed a suppressed trajectory to increase integral heat load on the structures of payloads. The duration of a flight phase above Mach 8 at altitudes between 30 km and 38 km was more than 60 seconds. The nose and forebody section of the payload is made of the CMC structures. Three canards with a CMC thermal protection were equipped with thermal management experiments to verify the thermal efficiency of these methods. All engineering science experiments like aerothermal heating of the nose and forebody, CMC material response at temperatures above 2200 K, hypersonic thermal management, shock wave boundary layer interaction, CFRP module with cork coating for high temperature applications, high temperature fin leading edge and radiometer sensors provided unique flight data. A reduced in-flight 3 DoF trajectory simulation running on the flight computer determined the ignition time of the third stage which allowed improved experiment conditions in terms of Mach number and apogee altitude even in the presence of external perturbations

Selected results of the hypersonic flight experiment STORT

The three-stage rocket configuration of the hypersonic experiment STORT with several scientific payloads concerning hypersonic technologies was launched successfully from the Andøya Space launch site in northern Norway on 26th June 2022. The third stage performed a suppressed trajectory to increase integral heat load on the payload structures. The vehicle traveled at speeds above Mach 8 at altitudes between 30 km and 38 km for more than 60 seconds. The nose and forebody section of the payload was made of CMC structures. Three canards with a CMC thermal protection were equipped with thermal management experiments to verify the thermal efficiency of these methods. All engineering science experiments like aerothermal heating of the nose and forebody, CMC material response at temperatures above 2200 K, hypersonic thermal management, shock wave boundary layer interaction, CFRP module with cork coating for high temperature applications, high temperature fin leading edge and radiometer sensors provided unique flight data. A reduced in-flight 3 DoF trajectory simulation running on the flight computer determined the ignition time of the third stage which allowed improved experiment conditions in terms of Mach number and apogee altitude even in the presence of external perturbation

Database of Near-Wall Turbulent Flow Properties of a Jet Impinging on a Solid Surface under Different Inclination Angles

In the present paper, direct numerical simulation (DNS) and particle image velocimetry (PIV) have been applied complementarily in order to generate a database of near-wall turbulence properties of a highly turbulent jet impinging on a solid surface under different inclination angles. Thereby, the main focus is placed on an impingement angle of 45°, since it represents a good generic benchmark test case for a wide range of technical fluid flow applications. This specific configuration features very complex flow properties including the presence of a stagnation point, development of the shear boundary layer and strong streamline curvature. In particular, this database includes near-wall turbulence statistics along with mean and rms velocities, budget terms in the turbulent kinetic energy equation, anisotropy invariant maps, turbulent length/time scales and near-wall shear stresses. These properties are useful for the validation of near-wall modeling approaches in the context of Reynolds-averaged Navier–Stokes (RANS) and large-eddy simulations (LES). From this study, in which further impingement angles (0°, 90°) have been considered in the experiments only, it turns out that (1) the production of turbulent kinetic energy appears negative at the stagnation point for an impingement angle other than 0° and is balanced predominantly by pressure-related diffusion, (2) quasi-coherent thin streaks with large characteristic time scales appear at the stagnation region, while the organization of the flow is predominantly toroidal further downstream, and (3) near-wall shear stresses are low at the stagnation region and intense in regions where the direction of the flow changes suddenly

Design, Manufacturing and Assembly of the STORT Hypersonic Flight Experiment Thermal Protection System

STORT is a DLR project focused on testing of key technologies for flight at hypersonic Mach numbers of higher than 8 for a relatively long time. The overarching aim of the project is to support cost reduction of future space transportation systems while at the same time keeping them highly reliable. To this end, reusability of all stages of future launcher systems is a prerequisite. For first stages, a Mach number of 8-10 seems to be the optimum staging velocity, which means that technologies for the return flight of first stages at those speeds need to be developed and validated. Consequently, STORT aimed at achieving operating conditions representative of such high-energetic reentry flights for reusable first stages at Mach 8, to support the optimization and validation of technologies and simulation tools for the development of future space transportation systems. The present paper thus describes the design, manufacturing and integration of the rocket forebody assembly up to the launch of the vehicle. In addition, an overview of the collected flight data from the thermal protection system sensors is given. The forebody thermal protection system requires the use of ceramic matrix composite material for protection from the high heat loads experienced during the flight. In the present case the thermal protection system was constituted by C/C-SiC composite structures built in-house by DLR. The main elements were a conical nose element and four thin-walled shell segments manufactured via filament winding of carbon fibers. Via an in-situ joining process, integral fixation brackets from CMC material were permanently attached to the shells. The underlying forebody main structure to which the thermal protection system structures were connected was made from aluminum

Dietary α-linolenic acid diminishes experimental atherogenesis and restricts T cell-driven inflammation

Aims Epidemiological studies report an inverse association between plant-derived dietary α-linolenic acid (ALA) and cardiovascular events. However, little is known about the mechanism of this protection. We assessed the cellular and molecular mechanisms of dietary ALA (flaxseed) on atherosclerosis in a mouse model. Methods and results Eight-week-old male apolipoprotein E knockout (ApoE−/−) mice were fed a 0.21 % (w/w) cholesterol diet for 16 weeks containing either a high ALA [7.3 % (w/w); n = 10] or low ALA content [0.03 % (w/w); n = 10]. Bioavailability, chain elongation, and fatty acid metabolism were measured by gas chromatography of tissue lysates and urine. Plaques were assessed using immunohistochemistry. T cell proliferation was investigated in primary murine CD3-positive lymphocytes. T cell differentiation and activation was assessed by expression analyses of interferon-γ, interleukin-4, and tumour necrosis factor α (TNFα) using quantitative PCR and ELISA. Dietary ALA increased aortic tissue levels of ALA as well as of the n−3 long chain fatty acids (LC n−3 FA) eicosapentaenoic acid, docosapentaenoic acid, and docosahexaenoic acid. The high ALA diet reduced plaque area by 50% and decreased plaque T cell content as well as expression of vascular cell adhesion molecule-1 and TNFα. Both dietary ALA and direct ALA exposure restricted T cell proliferation, differentiation, and inflammatory activity. Dietary ALA shifted prostaglandin and isoprostane formation towards 3-series compounds, potentially contributing to the atheroprotective effects of ALA. Conclusion Dietary ALA diminishes experimental atherogenesis and restricts T cell-driven inflammation, thus providing the proof-of-principle that plant-derived ALA may provide a valuable alternative to marine LC n−3 F

Measurements of fiducial and differential cross sections for Higgs boson production in the diphoton decay channel at s√=8 TeV with ATLAS

Measurements of fiducial and differential cross sections are presented for Higgs boson production in proton-proton collisions at a centre-of-mass energy of s√=8 TeV. The analysis is performed in the H → γγ decay channel using 20.3 fb−1 of data recorded by the ATLAS experiment at the CERN Large Hadron Collider. The signal is extracted using a fit to the diphoton invariant mass spectrum assuming that the width of the resonance is much smaller than the experimental resolution. The signal yields are corrected for the effects of detector inefficiency and resolution. The pp → H → γγ fiducial cross section is measured to be 43.2 ±9.4(stat.) − 2.9 + 3.2 (syst.) ±1.2(lumi)fb for a Higgs boson of mass 125.4GeV decaying to two isolated photons that have transverse momentum greater than 35% and 25% of the diphoton invariant mass and each with absolute pseudorapidity less than 2.37. Four additional fiducial cross sections and two cross-section limits are presented in phase space regions that test the theoretical modelling of different Higgs boson production mechanisms, or are sensitive to physics beyond the Standard Model. Differential cross sections are also presented, as a function of variables related to the diphoton kinematics and the jet activity produced in the Higgs boson events. The observed spectra are statistically limited but broadly in line with the theoretical expectations

Evidence for the Higgs-boson Yukawa coupling to tau leptons with the ATLAS detector

Results of a search for H → τ τ decays are presented, based on the full set of proton-proton collision data recorded by the ATLAS experiment at the LHC during 2011 and 2012. The data correspond to integrated luminosities of 4.5 fb−1 and 20.3 fb−1 at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV respectively. All combinations of leptonic (τ → `νν¯ with ` = e, µ) and hadronic (τ → hadrons ν) tau decays are considered. An excess of events over the expected background from other Standard Model processes is found with an observed (expected) significance of 4.5 (3.4) standard deviations. This excess provides evidence for the direct coupling of the recently discovered Higgs boson to fermions. The measured signal strength, normalised to the Standard Model expectation, of µ = 1.43 +0.43 −0.37 is consistent with the predicted Yukawa coupling strength in the Standard Model