Fraunhofer-Publica
The Fraunhofer-Publica has been successfully documenting the research results of the Fraunhofer-Gesellschaft for over 30 years. The platform enables the collaborative linking of research-relevant objects and disseminates within the international scientific community.
The Fraunhofer-Publica thus fulfils its responsibility to promote the transfer of knowledge and know-how to industry and society.
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Research outputs
As an application-oriented research organisation, Fraunhofer aims to conduct highly innovative and solution-oriented research - for the benefit of society and to strengthen the German and European economy.
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Projects
Fraunhofer is tackling the current challenges facing industry head on. By pooling their expertise and involving industrial partners at an early stage, the Fraunhofer Institutes involved in the projects aim to turn original scientific ideas into marketable products as quickly as possible.
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Researchers
Scientific achievement and practical relevance are not opposites - at Fraunhofer they are mutually dependent. Thanks to the close organisational links between Fraunhofer Institutes and universities, science at Fraunhofer is conducted at an internationally first-class level.
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Institutes
The Fraunhofer-Gesellschaft is the leading organisation for applied research in Europe. Institutes and research facilities work under its umbrella at various locations throughout Germany.
Recent Additions
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PublicationAutoclaved steel slag coarse aggregate( 2023)A large-scale utilization of steel slag as an aggregate in green concrete industry has been hindered by steel slag’s inherent volume instability. This study presents a volume stability modification procedure to develop autoclaved steel slag aggregates (ASA), investigating ASA’s characteristics and the performance of concrete made with ASA. A total of seven concrete mixes with varying ASA and original steel slag aggregate (OSA) substitution ratios (0%, 30%, 50%, 70%, 100%) was assessed for expansibility, mechanical properties (i.e. compressive strength, splitting tensile strength, axial compression behavior), and durability performance under wetting and drying cycles. The study shows that autoclaving treatments significantly changed the characteristics of steel slag aggregates: the f-CaO content, water absorption, and crushing value were reduced by 84%, 41%, and 22%, respectively. Concrete containing ASA demonstrated lower workability, higher apparent density, greater values in both compressive and splitting tensile strength, and satisfactory durability performance under wetting and drying cycles compared to natural aggregate concrete (NAC). An optimal ASA replacement ratio of 50% led to enhancements in compressive strength, split tensile strength, and elastic modulus by 33.2%, 24.4%, and 20%, respectively, while reducing compression toughness by 16%. Overall, this study introduced a feasible approach for utilizing steel slag to produce high-quality aggregates for green concrete application.
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Journal
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PublicationPilot-scale co-precipitation synthesis of a novel active ingredient made of ultrasmall iron (oxyhydr)oxide nanoparticles for the treatment of hyperphosphatemia( 2024)Due to its simplicity, co-precipitation is the most commonly used method for producing iron (oxyhydr)oxide nanoparticles. However, it is reported to be sensitive to changes in process parameters, which complicates scale-up and is why only volumes up to 1.2 L have been described in the literature. This study aims to demonstrate the scale-up of a co-precipitation synthesis to 100 L using the example of a new phosphate-binding active ingredient based on iron (oxyhydr)oxide. The synthesis was shown to be very robust to changes in synthesis parameters and stirrer geometries. The in vitro phosphate-binding efficacy and the yield were maintained in all five scales tested. Only the content of the components in the nanoparticles varied slightly. However, Mössbauer spectroscopy, dynamic light scattering (DLS), and attenuated total reflection Fourier transform infrared spectroscopy (FT-IR) revealed no evidence of structural changes, but a reduction in the size of the iron (oxyhydr)oxide cores and the total core-shell nanoparticle sizes. Overall, this study has successfully demonstrated that ultrasmall iron (oxyhydr)oxide nanoparticles can be produced on a pilot scale by co-precipitation with a yield of >40 g L-1.
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PublicationMoisture diffusion and tensile properties of epoxy-based and polyurethane-based flax-glass hybrid FRP under hygrothermal and weathering environments( 2023)This research presents tensile modulus and strength of flax-glass hybrid FRP (HFRP) flat coupons with different fibre volume fractions and fabric stacking sequences under constant hygrothermal (50 °C and 95% RH) and cyclic weathering (water spray-ultraviolet radiation) environments for six months. Two types of polymer (i.e., epoxy (EP) and polyurethane (PUR)) were employed in HFRP. Fourier transformed infrared spectroscopy (FTIR) was performed to identify the changes in functional groups of flax fibres and polymer matrix after exposures. The glass transition temperature (Tg) of polymer matrix was measured by differential scanning calorimetry (DSC), which was used to study the influence of environmental exposure on Tg. The 3D diffusion coefficients of EP-based flax FRP and glass FRP laminates were determined based on experimental moisture uptake and Fick's law. A coupled mass diffusion-stress analysis based on finite element (FE) model was conducted to simulate the moisture diffusion and swelling behaviour of HFRP. The results showed that hygrothermal and weathering exposures hardly affected tensile modulus of HFRP regardless of the matrix type. After the environmental exposure, EP-based HFRP experienced lower retention ratio of tensile strength (65.4-88.0%) compared to PUR-based HFRP (80.7-94.1%) because of higher moisture absorption in the EP-based HFRP. The influence of fabric stacking sequence on tensile strength reduction varied with different fibre volume fractions in EP-based HFRP, which was explained by the combined effects of the internal stress and damage propagation at flax-glass interface.
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PublicationQualitative evaluation of flip chip solder bumps produced by stencil printing of solder paste on various electroless nickel/gold metallizations( 2006)Stencil printing of solder paste in conjunction with electroless Ni/Au UBM on Al metallization offers the most economical method for wafer bumping either for Flip chip applications or for WLCSP packages. This paper deals in detail with the bumping process of 6? wafers at 300µm and 200µm pitch and investigates the bump interface integrity for different Au flash thicknesses on 5µm Ni. The bump height produced is 108±5µm with Sn63Pb37 and Sn4Ag0.5Cu compositions. Bumped chips have undergone high temperature storage at 150oC and up to 10 multiple reflow passes. Interesting results show that the shear strength of bumps with 5µmNi/26nmAu/Sn4Ag0.5Cu interface is about 97.1±8.3 MPa; very close to the standard 5µmNi/80nmAu UBM used so far in electroless processes. Furthermore, Sn4Ag0.5Cu bumps with only 5µm Ni UBM (without flash Au) has shown significant shear strength of about 80.4 ± 8.9 MPa which corresponds to about 17% reduction in strength. The prevailing shear fracture mode for all bumped chips is solder bulk fracture. The results imply that a possible reduction in Au flash thickness or a complete absence of Au can be potentially applied without any compromise in the mechanical integrity and robustness of the bumps.
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PublicationAlgorithm for the Automatic Verification of Complex Mixed-Signal ICs regarding ESD-Stress( 2005)In this publication, an algorithm is described which automates the verification of a com¬p¬lex integrated circuit (IC) with regard to the behavior under transient high voltage impulses (e.g. ESD). Here, the complexity of the whole circuit diagram is being reduced in a first step in order to carry out a transient simulation with high current simulation models time-efficiently in a second step. The nowadays usual manual extraction of the relevant circuit parts for such a transient analysis is then automated and therefore, the error susceptibility of this process is minimized as well. The algorithm is embedded in a commercial design frame¬work for IC-design and uses the data structures already existing.