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Photovoltaic modules: Reliability and sustainability
No full textPhotovoltaic modules have developed into mass products sold in billions and applied all over the world enabling a renewable energy supply. Reliability and sustainability are key factors for the success of Photovoltaics in all climate zones. The second edition of this interdisciplinary book provides insight into relevant environmental aspects (climates), material and module testing equipment and approaches, service life prediction modelling and standardisation of wafer-based photovoltaic modules. The book also addresses recent research and developments on the sustainability assessment of photovoltaic modules including end of life measures and legislation
Improved 3D modeling of end-pumped continuous-wave Ho3+:YAG lasers by inclusion of temperature-dependent material parameters
No full textIn this work, we present an accurate model for simulating continuous wave laser resonators based on a beam propagation method including temperature-dependent material parameters. An experimental Ho3+:YAG resonator is used to validate the model
Masked Accelerators and Instruction Set Extensions for Post-Quantum Cryptography
No full text414460Side-channel attacks can break mathematically secure cryptographic systems leading to a major concern in applied cryptography. While the cryptanalysis and security evaluation of Post-Quantum Cryptography (PQC) have already received an increasing research effort, a cost analysis of efficient side-channel countermeasures is still lacking. In this work, we propose a masked HW/SW codesign of the NIST PQC finalists Kyber and Saber, suitable for their different characteristics. Among others, we present a novel masked ciphertext compression algorithm for non-power-of-two moduli. To accelerate linear performance bottlenecks, we developed a generic Number Theoretic Transform (NTT) multiplier, which, in contrast to previously published accelerators, is also efficient and suitable for schemes not based on NTT. For the critical non-linear operations, masked HW accelerators were developed, allowing a secure execution using RISC-V instruction set extensions. With the proposed design, we achieved a cycle count of K:214k/E:298k/D:313k for Kyber and K:233k/E:312k/D:351k for Saber with NIST Level III parameter sets. For the same parameter sets, the masking overhead for the first-order secure decapsulation operation including randomness generation is a factor of 4.48 for Kyber (D:1403k) and 2.60 for Saber (D:915k).2022
Zero-Rate-Output Anomaly in Lissajous-FM Gyroscopes with Electrostatic Ring Resonators
No full textThis paper investigates the origin of zero-rate-output (ZRO) anomalies observed in Lissajous frequency-modulated (LFM) MEMS gyroscopes employing electrostatic ring resonators. Although LFM detection offers high scale-factor stability through frequency-based angular-rate encoding, residual bias errors often emerge even under zero angular rate. Experimental measurements reveal the presence of a second-harmonic component in the frequency modulation that cannot be explained by conventional linear cross-axis coupling models. To clarify this behavior, a theoretical model is developed considering the inclination of parallel-plate electrostatic transducers under large-amplitude wineglass-mode vibration. The analysis shows that the electrostatic stiffness becomes quadratically dependent on the vibration amplitude of the orthogonal mode, producing a second-order coupling term proportional to cos (2θ). Experimental results obtained using an FPGA-based dual-axis control system confirm that the amplitude of the second-harmonic component scales with the square of the drive voltage, validating the proposed model. These findings demonstrate that plate-tilt-induced nonlinear coupling is a major source of ZRO fluctuation in LFM gyroscopes.10
Spin Dynamics with Inertia in Ferromagnetic Thin Films
No full textUnderstanding spin dynamics on femto- and picosecond timescales offers new opportunities for faster and more efficient devices. On short time scales, the inertia term in the LLG equation becomes important, leading to the nutation of spins. However, experimental observation of nutation is still in its infancy. Here, we experimentally demonstrate a non-resonant excitation of inertial spin dynamics in ultrathin Ni80Fe20 films leading to nutation at a frequency of ∼ 0.1 THz, measured by time-resolved magneto optical Kerr effect (TR-MOKE). The inertial regime has a lifetime of more than 300ps
Effect of seven anti-tuberculosis treatment regimens on sputum microbiome: a retrospective analysis of the HIGHRIF study 2 and PanACEA MAMS-TB clinical trials
No full texte913e922Background: Respiratory tract microbiota has been described as the gatekeeper for respiratory health. We aimed to assess the impact of standard-of-care and experimental anti-tuberculosis treatment regimens on the respiratory microbiome and implications for treatment outcomes. Methods: In this retrospective study, we analysed the sputum microbiome of participants with tuberculosis treated with six experimental regimens versus standard-of-care who were part of the HIGHRIF study 2 (NCT00760149) and PanACEA MAMS-TB (NCT01785186) clinical trials across a 3-month treatment follow-up period. Samples were from participants in Mbeya, Kilimanjaro, Bagamoyo, and Dar es Salaam, Tanzania. Experimental regimens were composed of different combinations of rifampicin (R), isoniazid (H), pyrazinamide (Z), ethambutol (E), moxifloxacin (M), and a new drug, SQ109 (Q). Reverse transcription was used to create complementary DNA for each participant's total sputum RNA and the V3-V4 region of the 16S rRNA gene was sequenced using the Illumina metagenomic technique. Qiime was used to analyse the amplicon sequence variants and estimate alpha diversity. Descriptive statistics were applied to assess differences in alpha diversity pre-treatment and post-treatment initiation and the effect of each treatment regimen. Findings: Sequence data were obtained from 397 pre-treatment and post-treatment samples taken between Sept 26, 2008, and June 30, 2015, across seven treatment regimens. Pre-treatment microbiome (206 genera) was dominated by Firmicutes (2860 [44%] of 6500 amplicon sequence variants [ASVs]) at the phylum level and Streptococcus (2340 [36%] ASVs) at the genus level. Two regimens had a significant depressing effect on the microbiome after 2 weeks of treatment, HR20mg/kgZM (Shannon diversity index p=0·0041) and HR35mg/kgZE (p=0·027). Gram-negative bacteria were the most sensitive to bactericidal activity of treatment with the highest number of species suppressed being under the moxifloxacin regimen. By week 12 after treatment initiation, microbiomes had recovered to pre-treatment level except for the HR35mg/kgZE regimen and for genus Mycobacterium, which did not show recovery across all regimens. Tuberculosis culture conversion to negative by week 8 of treatment was associated with clearance of genus Neisseria, with a 98% reduction of the pre-treatment level. Interpretation: HR20mg/kgZM was effective against tuberculosis without limiting microbiome recovery, which implies a shorter efficacious anti-tuberculosis regimen with improved treatment outcomes might be achieved without harming the commensal microbiota. Funding: European and Developing Countries Clinical Trials Partnership and German Ministry of Education and Research.41
Additive manufacturing of radiation shielding for small satellites
No full textAn increasing demand on reliability in the automotive industry, driven by the development of autonomous driving, has led to a high availability of inexpensive electronics with high potential for space applications. Several of these applications have already been proposed within the NewSpace trend. However, the high-radiation environment inherent to space operations lies outside the automotive hardware development scope and is therefore often the showstopper for using such electronics for space applications. This work examines the possibility of designing and manufacturing weight- and cost-efficient radiation shielding using additive manufacturing. A printable shielding material, composed of tungsten powder embedded in the high-performance thermoplastic polyether-ether-ketone (PEEK), was developed and used to design a multi-material, multifunctional sandwich structure for local shielding of a representative automotive MEMS sensor. Radiation simulation was used to find the most efficient geometry and distribution of the shielding material. Additionally, the simulation has shown the required amount of shielding material to keep the total ionising dose below the previously tested limits of the sensor. The local shielding realised by additive manufacturing allows a minimal use of tungsten and thereby weight benefits compared to traditional shielding in aluminium boxes. The design will be demonstrated on the University of Stuttgart CubeSat mission, SOURCE, by comparing a shielded and unshielded area of the sandwich. The demonstrated shielding concept can easily be transferred to other hardware and missions and can thereby reduce both weight and cost of future spacecrafts
Corrosion of adhesively bonded alloys in maritime environments: A review
No full textThere is a growing demand for material and resource-efficient structures and innovative materials in the transport sector, particularly for maritime applications. To efficiently and seamlessly connect similar and different high-performance materials in marine and naval constructions, modern joining techniques such as adhesive bonding are required. For adhesive joining technology to be applicable in maritime environments, the corrosion stability of bonded joints is of crucial importance, as harsh conditions such as large temperature differences, salt water exposure, and extended time-dependent loads prevail, both during production and use. This paper reviews the state of research on the durability and corrosion of adhesively bonded joints in maritime environments and offers perspectives on this field. The idea behind is to comprehensively present the research areas currently pertinent to the design of corrosion-resistant adhesive composites. The article highlights aspects ranging from the surface pre-treatment of materials to the simulation of corrosion processes that are highly relevant for adhesive bonds in marine structures. The comprehensive view, moreover, includes the classification of relevant adhesive systems, the fundamentals of wet and electrochemical de-adhesion processes of adhesives, the impact of environmental aging on the mechanical properties of adhesive joints as well as an overview of destructive and non-destructive testing suitable for such structures. Finally, the review provides perspectives on future interdisciplinary experimental and theoretical research in the field of aging and corrosion that is likely to promote adhesive joining technologies for marine and naval constructions.14
Concept for a MEMS-based GC Chip as a Part of an Easy-to-Use Handheld System
No full text536540Gas chromatography (GC) is a powerful method to separate different analytes from an unknown mixture. The use of a GC-based analytical system at the point-of-interest is very promising, but also sets high demands. Volatile organic compounds (VOCs) are typical substances that can be used as indicator substances in environmental sensing, evaluation of food products or assessment of the suitability of recyclates. In order to handle these applications, there is a need for easy-to-use and portable devices. Miniaturized components, like the separation column, are therefore very promising. An overview of miniaturized chip-based GC columns from the literature is given. Based on comparison and evaluation, a new concept is derived and presented. This concept will overcome existing limitations. A future aim is to realize a miniaturized GC separation column based on this result together with other system components into a portable system