Low‐Temperature Co‐Fired Ceramic Substrates for High‐Performance Strain Gauges

Recent advances in the development of high gauge factor thin films for strain gauges prompt the research on advanced substrate materials. A glass ceramic composite has been developed in consideration of a high coefficient of thermal expansion (9.4 ppm/K) and a low modulus of elasticity (82 GPa) for the application as support material for thin‐film sensors. In the first part, constantan foil strain gauges were fabricated from this material by tape casting, pressure‐assisted sintering, and subsequent lamination of the metal foil on the planar ceramic substrates. The accuracy of the assembled load cells corresponds to accuracy class C6. That qualifies the load cells for the use in automatic packaging units and confirms the applicability of the low‐temperature co‐fired ceramic (LTCC) substrates for fabrication of accurate strain gauges. In the second part, to facilitate the deposition of thin‐film sensor structures to the LTCC substrates, pressure‐assisted sintering step is modified using smooth setters instead of release tapes, which resulted in fabrication of substrates with low average surface roughness of 50 nm. Titanium thin films deposited on these substrates as test coatings exhibited low surface resistances of 850 Ω comparable to thin films on commercial alumina thin‐film substrates with 920 Ω. The presented material design and advances in manufacturing technology are important to promote the development of high‐performance thin‐film strain gauges.     

Multilayer optics for the EUV and soft X-rays

1Introduction Engineersandscientistsinfieldsasdiverse asmicrolithographyandspaceastronomyhavea commonneedtouse“light”rangingfromEUV tothesoftX rayregion.Theextremeultraviolet andsoftX rayspectralregionliebetweentheul travioletandthehardX rayregionsoftheelec tromagneticspectrum.Inspiteofthesmooth transitionsbetweenthespectralsubdivisionsit’s worthtodefineroughlytheirapproximatebor ders[1]:extremeultravioletEUV～50nmto～5nm～25eVto～250eV,softX rayregion～5nmto～0.2nm～250eVto～6keV.The…     

Synthesis and Structural Characterization of Macrocyclic Plasmin Inhibitors

Two series of macrocyclic plasmin inhibitors with a C-terminal benzylamine group were synthesized. The substitution of the N-terminal phenylsulfonyl group of a previously described inhibitor provided two analogues with sub-nanomolar inhibition constants. Both compounds possess a high selectivity against all other tested trypsin-like serine proteases. Furthermore, a new approach was used to selectively introduce asymmetric linker segments. Two of these compounds inhibit plasmin with K_i values close to 2 nM. For the first time, four crystal structures of these macrocyclic inhibitors could be determined in complex with a Ser195Ala microplasmin mutant. The macrocyclic core segment of the inhibitors binds to the open active site of plasmin without any steric hindrance. This binding mode is incompatible with other trypsin-like serine proteases containing a sterically demanding 99-hairpin loop. The crystal structures obtained experimentally explain the excellent selectivity of this inhibitor type as previously hypothesized.     

Robust two-degrees of freedom linear quadratic gaussian position control for the front axle actuator of a steer-by-wire system

The Steer-by-Wire (SbW) system is a key technology for highly automated driving. For automated lateral vehicle guidance, the precise position control of the SbW Front Axle Actuator is an essential prerequisite. This contribution presents the modeling, control design, nominal performance, and stability analysis as well as the robustness analysis of the position control for the SbW Front Axle Actuator. Based on a nonlinear model of the plant a simplified linear system model is derived. This model yields the basis for the design of a Two-Degrees of Freedom Linear Quadratic Gaussian Control (2DOF LQG control), which allows an independent design of the command and the disturbance response. Besides an evaluation of the nominal control behavior, μ-analysis is applied to assess the robustness of performance and stability. Finally, real vehicle tests for different driving maneuvers are presented to verify simulation results.

     

Mapping the Binding Sites of UDP and Prostaglandin E2 Glyceryl Ester in the Nucleotide Receptor P2Y6

Cyclooxygenase-2 catalyzes the biosynthesis of prostaglandins from arachidonic acid and the biosynthesis of prostaglandin glycerol esters (PG-Gs) from 2-arachidonoylglycerol. PG-Gs are mediators of several biological actions such as macrophage activation, hyperalgesia, synaptic plasticity, and intraocular pressure. Recently, the human UDP receptor P2Y₆ was identified as a target for the prostaglandin E2 glycerol ester (PGE₂-G). Here, we show that UDP and PGE₂-G are evolutionary conserved endogenous agonists at vertebrate P2Y₆ orthologs. Using sequence comparison of P2Y₆ orthologs, homology modeling, and ligand docking studies, we proposed several receptor positions participating in agonist binding. Site-directed mutagenesis and functional analysis of these P2Y₆ mutants revealed that both UDP and PGE₂-G share in parts one ligand-binding site. Thus, the convergent signaling of these two chemically very different agonists has already been manifested in the evolutionary design of the ligand-binding pocket.     

Membranbasierte Bereitstellung von CO2 für die dezentrale Algenproduktion in einer Bioenergiefassade

This study emphasizes the importance of a sustainable energy supply with regard to climate change. A way is shown how a de-centralized heat supply in urban areas with renewable energies can be combined with algae production. The decentrally generated CO₂ emissions are made usable for biomass production by means of membrane separation technology. The operating behavior of the CO₂-selective membrane materials was observed over an operating period of almost 10 years. This provides solid evidence of the operability of the polymer membrane and membrane module technology. It enables further optimization of the separation process for future applications, also in a wider range of applications.     

Enhancement of biosludge dewatering using proteins through dual conditioning

In pulp and paper mills, effective biosludge dewatering is essential in wastewater treatment to reduce the large volume of biosludge that needs to be treated and disposed. The dewatering process normally requires the use of polymers from petroleum-based sources. This study explores the potential of using cationic proteins such as protamine for biosludge dewatering through dual conditioning with a small amount of a synthetic anionic polymer such as anionic polyacrylamide (APAM). The results show that dual conditioning provides substantial synergistic enhancements in dewatering. The maximum cake solids content of biosludge achieved by adding protamine (7.5%) alone was 12%. By dual conditioning with a small amount of APAM (0.1%), not only the cake solids content was increased to 16%, but also the amount of protamine addition was substantially lowered to 2%. These results, coupled with the change in zeta potential of the particles in the biosludge samples, suggest that the cationic protamine reduced the negative charge of the particles, allowing smaller particles to agglomerate and providing a positively charged framework for the subsequent addition of the negatively charged APAM. After adding APAM, substantial floc-bridging occurred, allowing smaller flocs to aggregate into larger flocs. These synergistic effects can lower the wastewater treatment cost by reducing the amount of synthetic polymer and by applying low-value proteins from natural sources.     

Manufacturing and deformation behavior of alumina and zirconia helical springs at room temperature

Ceramic helical springs with identical dimensions were produced by hard machining from alumina, alumina toughened zirconia (ATZ), and tetragonal zirconia polycrystals (TZP) stabilized with different oxides. According to the results of the spring constant determination under deformation rates of 3 mm/min, the deformation behavior of all ceramic springs obeys to Hook's law. However, variation of the deformation rate, tests under constant load, and spring recovery behavior revealed differences in the deformation behavior of alumina, TZP, and ATZ springs. Alumina springs exhibited time-independent deformation in all tests. In contrast, anelastic deformation at room temperature was demonstrated in all springs containing TZP. This deformation is completely reversible over a period of several days. Anelastic behavior is particularly pronounced in Y-TZP springs, whereas Ce-TZP springs exhibit comparatively very low but still reliably detectable anelasticity. Oxygen vacancies in the TZP ceramic are considered the most likely explanation for the anelastic behavior of TZP springs at room temperature.     

Analytical determination of compounds released during pyrolysis,smoldering, and combustion experiments with insulation materials from renewable resources

Obviously, the use of insulation materials from renewable resources in buildings could provide benefits regarding environmental protection and sustainable management. Nevertheless, their market share in Germany is estimated to be about 7% because of a partial lack of knowledge about their properties, and therefore, of construction certifications. This work was intended to close a knowledge gap concerning emissions during pyrolysis, smoldering, and combustion of commercial insulating materials made from wood, cellulose, meadow grass, hemp, jute, cork, and seaweed as well as polystyrene for comparison reasons. Laboratory-scale experiments were conducted and the measurement of thermal decomposition products was done with gas chromatography combined with mass spectrometry (GC/MS). It was realized that almost all the products could be assigned to the following eight substance classes: carbohydrates, aldehydes/ketones, carbonic acids/esters, substituted phenols, furans, aliphatic hydrocarbons, substituted benzenes, and polycyclic aromatic hydrocarbons. Substance spectra were generated that showed certain conformities, especially between the insulating materials made from wood, cellulose, and meadow grass as well as hemp and jute. Comparisons of the sum of peak areas in the GC/MS-chromatograms provided indications of the relative extent of thermal decomposition product emissions. Calculations according to (∑peak areas _{renewable material})/(∑peak areas _polystyrene) revealed factors between 0.18 (wood, cork) and 0.028 (meadow grass). In the thermal emissions, defined hazardous substances or substance groups were frequently measured. These were included in a toxicity evaluation by which, inter alia, advantages of the natural products compared to polystyrene could be demonstrated.