Open Access

Laser-induced fluorescence (LIF) is a non-invasive optical diagnostics technique frequently used in reactive media to measure physical properties such as gas-phase species concentrations and temperature. It provides important information for understanding reaction and transport processes. For deriving detection schemes that provide selective and quantitative information, fluorescence spectra of the species of interest as well as potential interference sources must be simulated. LIFSim 4.0 is a modular software for simulating absorption, LIF excitation, and LIF emission spectra of NO, SiO, OH, and O2 that also can be extended by the user to include other species. Line positions, line broadening, and collisional quenching are calculated based on spectroscopic data from literature. The code provides spectral analysis tools to interrogate and analyze sensitive spectral regions suitable for derivation of temperature from multi-line LIF measurements. The library includes fitting functions optimized for enhancing and accelerating the post-processing of stacked LIF images with varied excitation wavelength for temperature imaging and separation of the target LIF signal from broad-band or scattering background as well as tools for assessing the validity of results in non-ideal measurement situations.

One promising PV module technology in terms of reducing expensive consumables while keeping the performance on a high level is the N.I.C.E.™ (New Industrial Solar Cell Encapsulation) module technology from Apollon Solar that is based on mechanical pressing contacts. In this paper, we investigate the question if the N.I.C.E.™ module technology is well suited for temperature-sensitive silicon heterojunction (SHJ) solar cells. We present challenges encountered during the ramp-up of our lab-scale manufacturing from 1x1 to 3x4 modules. In the experimental study, we used SHJ cells with different front metal pastes and could demonstrate the high performance of N.I.C.E.™ technology irrespective of the type of paste. Record aperture area module efficiencies of 20.6% are achieved and the LIV parameters are modeled via SunSolve™ simulations. We derive from our investigations that this eco-friendly, recyclable technology is well competitive to standard laminate-based module technology.

In addition to human donor bones, bone models made of synthetic materials are the gold standard substitutes for biomechanical testing of osteosyntheses. However, commercially available artificial bone models are not able to adequately reproduce the mechanical properties of human bone, especially not human osteoporotic bone. To overcome this issue, new types of polyurethane-based synthetic osteoporotic bone models have been developed. Its base materials for the cancellous bone portion and for the cortical portion have already been morphologically and mechanically validated against human bone. Thus, the aim of this study was to combine the two validated base materials for the two bone components to produce femur models with real human geometry, one with a hollow intramedullary canal and one with an intramedullary canal filled with synthetic cancellous bone, and mechanically validate them in comparison to fresh frozen human bone. These custom-made synthetic bone models were fabricated from a computer-tomography data set in a 2-step casting process to achieve not only the real geometry but also realistic cortical thicknesses of the femur. The synthetic bones were tested for axial compression, four-point bending in two planes, and torsion and validated against human osteoporotic bone. The results showed that the mechanical properties of the polyurethane-based synthetic bone models with hollow intramedullary canals are in the range of those of the human osteoporotic femur. Both, the femur models with the hollow and spongy-bone-filled intramedullary canal, showed no substantial differences in bending stiffness and axial compression stiffness compared to human osteoporotic bone. Torsional stiffnesses were slightly higher but within the range of human osteoporotic femurs. Concluding, this study shows that the innovative polyurethane-based femur models are comparable to human bones in terms of bending, axial compression, and torsional stiffness.

The combination of trimethoprim and sulfamethoxazole as a fixed-dose combination in the ratio 1:5 is known as cotrimoxazole. It is used as antibiotic to treat a variety of bacterial infections. Cotrimoxazole is part of the World Health Organization’s list of essential medicines. Cotrimoxazole is an example of a drug that was partially unavailable in Germany during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic and the Ukraine war. The dependency on foreign sources of medicines is well known in Europe and resulted in the Pharmaceutical Strategy for Europe 2020, a strategy concept “will support the competitiveness and innovative capacity of the EU’s pharmaceutical industry”. High-performance thin-layer chromatography (HPTLC) is a cost-effective method for quantifying pharmaceutically active compounds. Diode-array detection (DAD) in conjunction with HPTLC can simultaneously detect ultraviolet‒visible (UV‒VIS) and fluorescence spectra directly from the plate. Visualization as a contour plot helps to identify the optimal wavelengths for compound quantification and reduce uncertainty in the determination. The quantification of trimethoprim and sulfamethoxazole is presented in a case study that highlights the key aspects for HPTLC quantification of pharmaceutical fixed-dose combinations with minimal uncertainty. HPTLC‒DAD allows quantification of trimethoprim and sulfamethoxazole with a required relative standard deviation of less than 2.5%.

Elastic moduli of scandium nitride (ScN) films are determined using a laser-based experimental method working with surface acoustic waves (SAWs). ScN, a semiconductor material with promising potential for various applications, crystallizes in the cubic rock salt (rs) structure. We investigate two samples of high-crystallinity ScN(111) films with thicknesses ∼200 and ∼300 nm, grown on Si(111) substrates by pulsed DC-magnetron co-sputtering and a sample with a fiber-textured ScN film (∼800 nm) on Si(001). From the shape evolution of laser-generated acoustic pulses, SAW dispersion curves were obtained in a frequency range of 50–500 MHz. In order to take advantage of the anisotropy of the film and substrate materials, measurements were performed for 10–15 SAW wavevector directions, which could be defined with a precision of 0.2°. Using perturbation theory with respect to the ratio of film thickness and SAW wavelength, two combinations of the three independent elastic constants of the high-crystallinity rs ScN films could be extracted from the measurement data. The surface roughness of the ScN films is accounted for with a simple model. Complete sets of the three elastic moduli were inferred in two different ways: (i) SAW dispersion data for the third sample were included in the extraction procedure; and (ii) the bulk modulus is set equal to a theoretical literature value. The extracted values for the three elastic constants are at variance with published theoretical results for single-crystal ScN. Possible reasons for these discrepancies are discussed.