Applied Research

Fraunhofer USA Center for Manufacturing Innovation CMI

Fiber optic gyroscopes are highly precise and accurate rotation sensors. They are used extensively in navigation and guidance systems installed in aircraft, ships, spacecraft and other complex vehicles. Lower performance range applications include turret stabilization systems, in helmet display stabilization and even the first down marker used in National Football League broadcasts. Such gyroscopes can also be used for research in combined quantum and classical navigation systems such as those envisioned for underwater autonomous vehicles. One of the advantages of fiber-optic gyroscopes over other inertial sensors is low noise emittance, which is important for military applications. The performance of these fiber-optic gyroscopes is closely related to the length of the fiber-optic coil and the accuracy of the winding pattern for that coil. Higher accuracy applications, require coils that can be multiple kilometers in length and successful winding of them requires motion control at the micron level, image processing and high-resolution tension control. Current practices require up to two weeks of highly-skilled manual labor to wind such a coil. Fraunhofer USA CMI engineers are developing a computercontrolled machine for coil winding that employs 17 coordinated servo axes that control its moving parts, allowing for micron level placement of the optical fiber in the required pattern configuration and precise tension control. The coils are wound from the inside out, meaning that the supplied length of fiber is divided into two connected spools before the winding process begins. Based on the required winding pattern the system then winds individual layers from each supply spool while fixing the inactive spool on the winding axis to prevent unwinding. Such an automated system with in-process image processing allows for highly accurate coil winding without physical intervention by operators. This enables strategic grade coils and gyroscopes with the key performance features of low cross-talk between signals in adjacent channels and very low thermal drift. Such high accuracy coil winding results in a low coil rejection rate. Furthermore, the automated system reduces labor costs and increases throughput. Fraunhofer USA is deploying this system to wind coils for various customers in multiple industries, including for an Asian aerospace company

Fraunhofer USA Center Midwest CMW

Transition to a hydrogen economy is viewed as a key strategy to reduce emissions of greenhouse gases and to reduce global warming. The use of hydrogen as a fuel requires fuel cells, typically proton-exchange membrane fuel cells, that are electrochemical cells capable of converting chemical energy into electricity through redox reactions. They utilize hydrogen and oxygen to sustain a chemical reaction to produce electricity continuously. Metallic bipolar plates are integral components of fuel cells, where they evenly distribute fuel and oxidant and collect the electric current that is generated. In a fuel stack, they connect individual fuel cells in series, conducting electricity from the anode of one cell to the cathode of the next. Energy efficient fuel cells require high performance bipolar plates that have several key attributes, including adequate fuel flow, fluid impermeability, hydrophobicity, mechanical stability, thermal transmission, and electrical conductance. These attributes define the design of the metallic bipolar plates, including the overall dimensions of the plates, the layout of the flow field, channel width and depth, and the degree of curvature of channels. Thus, precise channel geometries and tight manufacturing tolerances are essential for fuel cell efficiency. Maximum surface area at minimum weight requires complex plate designs and use of thin metals, typically less than 0.1 mm thick, which must be formed without tearing. High-volume production thereof is challenging. Engineers at Fraunhofer USA CMW have worked with colleagues at Clemson University and the Fraunhofer Institute for Production Technology IPT in Aachen, Germany to optimize approaches for the design and manufacturing of metallic bipolar plates for protonexchange membrane fuel cells. Firstly, flow field and channel geometries were optimized regarding fuel distribution, tooling capabilities and press capacities. Following the forming, processes and fixturing tools were developed for precision laser cutting of external and internal plate features and uniform laser joining of anode and cathode half plates. Assembled plates were coated by physical vapor deposition techniques. The coatings met key U.S. Department of Energy targets for corrosion resistance and interfacial contact resistance. Finally, gaskets were applied by screen printing around the outer periphery and media ports to complete bipolar plate demonstrators. These metallic bipolar plates were developed under a project supported by the South Carolina Department of Commerce and a global manufacturer of automotive components. The plates have applications for a wide range of vehicles and industrial equipment

Fraunhofer USA Center Midwest CMW

There is an increasing need for higher power devices that are more efficient, reduce strain on the electrical infrastructure, and are required for specialized industrial systems. To address this need, new high-power electronic devices are under development for application in a wide range of systems, including telecommunications, motor drives, power grids, electric vehicles, and industrial and locomotive traction control. These new devices require ultra-wide bandgap semiconductors with performance characteristics that are beyond the capabilities of the silicon carbide and gallium nitride materials used in electronic devices today. Various materials, including aluminum gallium nitride alloys, boron nitride, and diamond, are being tested for use in these new semiconductors, as are composites, combining multiple materials, where each material offers unique and necessary performance characteristics to the semiconductor. Engineers at Fraunhofer USA CMW have worked with colleagues at the Fraunhofer Institute for Microstructure of Materials and Systems IMWS in Halle, Germany to develop a technique to create single crystalline diamond nanomembranes that can be integrated with other semiconductor materials to create diodes with improved performance (see schematic figures A and B). The diamond nanomembranes are exfoliated from (i) bulk material via (ii) an ion implantation and (iii) separation process. These nanomembranes can then be transferred and further processed via a commercialized micro-transfer printing process (iv). Early prototypes showed an over ten-fold higher increased forward current density compared to traditional all-diamond diodes. Integration of diamond into these heterogeneous diodes also allowed for improved thermal management. Furthermore, the team demonstrated that chemical-mechanical polishing lowered surface roughness on the diamond nanomembranes, a prerequisite for including them in stacked devices such as thyristors, which are robust and operate like switchable diodes that are commonly used in high-voltage applications to control electric power flow. Under a program funded by the Defense Advanced Research Project Agency (DARPA), the Fraunhofer USA CMW engineers are now working with an industry partner to incorporate these diamond nanomembranes with other ultra-wide bandgap semiconductors that will allow devices to operate at higher voltages, frequencies and temperatures than what can currently be achieved with traditional materials, such as silicon carbide and gallium nitride. Access to such devices will be critical for a transition from a centralized to a distributed power grid. Interfacing renewables, such as solar and wind, as well as battery storage, with the grid at large requires the use of these devices

Fraunhofer USA Center for Manufacturing Innovation CMI

Accurate and rapid detection of specific biomolecules is vital in biomedical research and for the development of effective diagnostics. Current methods for rapid biomarker detection include testing for protein antigens and antibodies using lateral flow assays and testing for DNA and RNA using nucleic acid amplification techniques. The former can be rapidly performed at the point-of-sampling but have relatively high error rates, low sensitivity and poor selectivity. By contrast, the latter have relatively high accuracy, selectivity and sensitivity but need to be conducted by trained technicians in a laboratory and are relatively expensive and time consuming. Thus, there is a market need for diagnostics for a range of biomarkers that are both rapid to perform and inexpensive but that also have a high degree of accuracy and sensitivity and that are highly selective. Scientists at Fraunhofer USA CMW have worked with colleagues at the Fraunhofer Institute for Reliability and Microintegration IZM in Berlin, Germany and the Fraunhofer Institute for Cell Therapy and Immunology IZI in Leipzig, Germany to develop an alternative biosensor technology based on electrochemical detection of proteins binding to a functionalized electrode surface. For initial development of this tool, the team focused on detecting antibodies to the major spike protein antigen of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is indicative of viral infection, and to the human c-MYC protein, which is indicative of cancer. The team developed a sensor in which a boron-doped diamond surface acting as an electrode was functionalized by click chemistry with known peptide targets of the relevant antibody. Since this mode of functionalizing the sensor surface is modular, it can be tailored to detect any antibody and thus has applications across a wide range of diseases. Differential pulse voltammetry was deployed to measure antibodies in a human serum sample binding to the peptides on the diamond electrode surface. This resulted in a highly selective and quantitative signal. The diamond-based sensor was packaged with a standard microfluidic system to allow for sample flow over its surface, with electrical connections to the electrode made through the back side of the resulting device. The device plugs into a standard cartridge to allow fluid flow through a syringe pump and provides connection to a potentiostat to record the output signal. This packaging scheme allows for a portable and disposable sensor that could be mass produced and read using standard recording equipment at the point-of-sampling. This detection platform is now being further developed with multiple microfluidic channels to allow for internal controls and the analysis of multiple variables within samples. It is also being further validated with various human samples

Fraunhofer USA Center for Manufacturing Innovation CMI

Meat, mainly beef, pork, mutton, lamb and poultry, is consumed by humans worldwide and contributes a large proportion of the calorific intake in many countries. This is rapidly increasing as the middle class swells in nations with rapidly rising gross domestic product (GDP). Indeed, the average annual per capita consumption of meat worldwide is more than 40 kg, but this rises to 120 kg in the relatively affluent U.S.. The environmental consequences of such rising meat consumption, both in terms of land usage and greenhouse gas emissions, are considerable and contribute significantly to global concerns over limited availability of arable land and climate change. The generation of antibiotic resistant microbes is a further hazard of the large-scale cultivation of animals for meat. However, cultural drivers make it highly likely that meat consumption will continue to be viewed as aspirational by many human populations for decades to come. One leading potential solution to the land use and environmental consequences of meat consumption is to develop and use animal cell culture techniques to culture meat in bioreactors. However, the economical production of high-quality meat in bioreactors faces several hurdles, including the development of high yielding cell lines, the mass propagation of these cell lines, the fabrication of appropriate scaffolds upon which the cells can adhere, grow and divide to generate meatlike tissue, and appropriate bioreactor design for large-scale culturing, including allowing for flexing of the growing tissue to simulate the exercising of muscle in an animal. Scientists at Fraunhofer USA CMI have worked with colleagues at the Fraunhofer Institute for Molecular Biology and Applied Ecology IME in Aachen, Germany to address the issues of a lack of suitable scaffolds and bioreactors for cultured meat production by developing a wet spinner, a circular braider and a tension bioreactor. This has allowed for the wet spinning of plant based polymers to tensile strengths compatible with cultured meat production. The team also developed porous sponges for compression-based scaffolds and showed them to have compression strengths compatible with the culturing of meat products. In addition, muscle satellite cells were isolated from samples biopsied from cattle. These cells were shown to be able to attach to the fiber scaffolds, where they were induced to form myotubes, a developmental precursor of muscle. The cells could also attach to the sponge-like scaffolds. The team is also optimizing the growth medium for muscle satellite cell cultivation and differentiation. To avoid the use of fetal bovine serum, which is expensive and of animal origin, the necessary growth factors are being produced in a cell-free plant expression system. Together, these developments are highly promising for advancing the cultured meat industry.

Fraunhofer USA Center Midwest CMW

As dramatically demonstrated by the coronavirus disease 2019 (COVID-19) pandemic, current diagnostic assays are ill-equipped to deal with the rapid global spread of emerging and reemerging pathogens. These quantitative assays are incompatible with rapid point-of-infection testing. Rather they require biological samples to be collected and then transported to a testing laboratory for the isolation of nucleic acids and the performance of amplification tests to identify the presence and abundance of a specific pathogen. By contrast, crude antigen lateral flow, or strip, tests can be completed at the point of infection but are not quantitative and have higher error rates. Thus, there is considerable demand for accurate nucleic acid-based assays that can be performed at the point-of-infection. Scientists at Fraunhofer USA CMI have worked with colleagues at Boston University Medical Center, the Fraunhofer Institute for Production Technology IPT in Aachen, Germany and the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB in Stuttgart, Germany to incorporate printed hydrogels into fluorescent arrays. These arrays combine the accuracy of nucleic acid amplification tests with the simplicity, speed and convenience of lateral flow assays and are thus suitable for rapid, point-of-infection tests to detect viral pathogens. This platform has the added advantages of long-term stable storage of thermolabile reagents within the hydrogel matrix and multiplexing of outputs from multiple pathogens. The sensors detect the presence of specific pathogens in the samples through biological assays based on DNA amplification. Current development with Fraunhofer USA CMW focuses on integration of hydrogels with boron-doped diamond microelectrode arrays. The outcomes of these assays are thus converted into electrochemical signals. The research team initially developed this technology for the detection of four respiratory disease pathogens, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza virus A, influenza virus B and human rhinovirus. In addition to developing the relevant assays and the hydrogel matrix in which the assay components are encased, the team developed manufacturing processes for the printing of these hydrogel embedded arrays, including defining surface modifications of manufacturing-compatible plastics. Furthermore, the team designed a low-cost, portable reader for the assays and developed algorithms to process the output images to allow for automated analysis. Under a recently awarded grant with the National Institutes of Health (NIH), the research team is now extending this approach to blood borne pathogens, specifically to develop a diagnostic assay to detect human immunodeficiency virus (HIV), the causative agent of acquired immunodeficiency syndrome.

Fraunhofer USA continues to jointly represent the Fraunhofer-Gesellschaft network in the U.S. and has rapidly proven its institutional value as an expert in the U.S. market. Our joint program for internal strategic pre-competitive research continues to prove beneficial for transatlantic knowledge and technology transfer. This program facilitates our readiness to deploy resources across the Atlantic where and when needed. Our continued outreach with Fraunhofer institutes has led to Fraunhofer USA working with about 50 of the 76 research institutes in Germany at a time, to conduct joint project development activities in the U.S., engage in joint pre-competitive strategic technology development projects, executing on U.S.-industry projects or publicly funded projects. Some recent highlights of this transatlantic collaboration include a joint presence at the SC Battery Symposium and the U.S. Battery Show in Detroit with eight different Fraunhofer Institutes from Germany, Fraunhofer IFAM, Fraunhofer IGCV, Fraunhofer ILT, Fraunhofer IPA, Fraunhofer IPT, Fraunhofer ISC, Fraunhofer ISIT, and Fraunhofer IWS, contributing and engaging with local industry stakeholders. Fraunhofer Institutes were supporting delegation trips to the U.S. facilitated through the German Ministry for Economic Affairs and Climate Action BMWK as well. Fraunhofer USA additionally supports the Fraunhofer Institutes though joint engagements and activities with the German Embassy in Washington D.C. and the German Chambers of Commerce Abroad (AHK). Recent examples of these joint activities include “Germany on Campus”, an on-campus university event showcasing collaboration between the United States and Germany, and joint participation as a community partner. Other opportunities for Fraunhofer USA-Fraunhofer Institute engagement include personnel exchange though the Fraunhofer USA Research Scholar Program and the Fraunhofer Innovation Mobility program, which permits Fraunhofer-Gesellschaft staff to work in markets such as the U.S. to better align the science and technology activities and streamline transatlantic collaboration