Open Access

In the course of the last few years, our students are becoming increasingly unhappy. Sometimes they stop attending lectures and even seem not to know how to behave correctly. It feels like they are getting on strike. Consequently, drop-out rates are sky-rocketing. The lecturers/professors are not happy either, adopting an “I-don’t-care” attitude. An interdisciplinary, international team set in to find out: (1) What are the students unhappy about? Why is it becoming so difficult for them to cope? (2) What does the “I-don’t-care” attitude of professors actually mean? What do they care or not care about? (3) How far do the views of the parties correlate? Could some kind of mutual understanding be achieved? The findings indicate that, at least at our universities, there is rather a long way to go from “Engineering versus Pedagogy” to “Engineering Pedagogy”.

Technologie spielt im Sport schon immer eine große Rolle. Mit steigender Leistungsdichte im Spitzensport wird versucht mithilfe technischer Hilfsmittel dem Sportler die optimalen Umstände zu ermöglichen. Dazu gehört nicht nur Technik im Sportequiptment, sondern auch Sportuntersuchungen wie Leistungsdiagnostiken. Im Laufsport zählen dazu Ausdauer- und Krafttests. Bei Ausdauertests werden physiologische Parameter wie Laktat, Herzfrequenz oder Sauerstoffaufnahme gemessen. Zusätzlich wird die Lauftechnik für einen kurzen Zeitpunkt analysiert. Wie sich diese unter anhaltender Belastung verhält, wird nicht untersucht. Mit neuen Technologien im Bereich Bewegungsanalyse, können immer schneller größere Datensätze ausgewertet werden. Aus diesem Grund wird in dieser Studie die Lauftechnik über mehrere Zeitpunkte aufgezeichnet und nach Ermüdungserscheinungen untersucht. Dazu wurde am Institut für angewandte Trainingswissenschaften (IAT) während einer komplexen Leistungsdiagnostik im März 2021 bei einem Laufbandstufentest (4x2000m oder 4x3000m) die Lauftechnik von 15 Elite- und Elitenachwuchsläufer:innen (m=8, w=7) mithilfe eines 3D-Bewegungsanalyse Systems nach Veränderungen in Winkelstellung und Bodenreaktionskraft untersucht. Als physiologische Vergleichsparameter wurde Herzfrequenz und Laktat aufgenommen. Bei der Analyse der Daten wurden diese in der Gruppe betrachtet. Dabei haben sich schwach signifikante Veränderungen (p=0,047) der vertikalen Bodenreaktionskraft links am Ende der Stufe aufgezeigt. Weitere signifikante Unterschiede (p=0,020) sind im maximalen Kniehub links zu einem größerer Hüftwinkel am Ende sichtbar. Da sonst keine signifikanten Unterschiede zu sehen sind, lässt sich, bei dem hier durchgeführten Protokoll, nicht statistisch gesichert feststellen, ob auftretende Ermüdungserscheinungen die Lauftechnik beeinflussen und verändern. Um festzustellen, ob es geschlechts- oder protokollanhängige Effekte hinsichtlich einer ermüdungsbedingte Lauftechnikveränderung gibt, wurde auch dies statistisch untersucht. Hier zeigten sich jeweils in einzelnen Parametern signifikante Unterschiede (Parameter TO\_knee\_left; p=0,026) in der Geschlechtsspezifik und in der protokollabhängigen Untersuchung (Parameter TSw\_hip\_left; p=0,04) Für weitere Studien zur Untersuchung von Lauftechnikveränderung sollten umfangreichere physiologische Daten zur genaueren Betrachtung der Ermüdung verwendet werden. Grundsätzlich müsste das Protokoll auf eine maximale Ausbelastung (beispielsweise Dauerstufentest von 10-15km oder Ausbelastungs-/Abbruchtest) ausgelegt sein. Grundlegend ist festzustellen, dass sich Simi-Shape als 3D-Bewegungsanalyse-Methode eignet, um spezifische Parameter in der Lauftechnik zu diagnostizieren, gerade hinsichtlich der Effizienz im Auswerteprozess.

In this paper, a crack opening stress equation for in-phase and out-of-phase thermomechanical fatigue (TMF) loading is proposed. The equation is derived from systematic calculations of the crack opening stress with a temperature dependent strip yield model for both plane stress and plane strain, different load ratios and different ratios of the temperature dependent yield stress in compression and tension. Using a load ratio scaled by the ratio of the yield stress in compression and tension, the equation accounts for the effect of the temperature dependent yield stress and the constraint on the crack opening stress. Based on the scaling relation established in this paper, Newman's crack opening stress equation for isothermal loading is enabled to predict the crack opening stress under TMF loading.

The aim of this study was to develop a biomechanically validated finite element model to predict the biomechanical behaviour of the human lumbar spine in compression. For validation of the finite element model, an in vitro study was performed: Twelve human lumbar cadaveric spinal segments (six segments L2/3 and six segments L4/5) were loaded in axial compression using 600 N in the intact state and following surgical treatment using two different internal stabilisation devices. Range of motion was measured and used to calculate stiffness. A finite element model of a human spinal segment L3/4 was loaded with the same force in intact and surgically altered state, corresponding to the situation of biomechanical in vitro study. The results of the cadaver biomechanical and finite element analysis were compared. As they were close together, the finite element model was used to predict: (1) load-sharing within human lumbar spine in compression, (2) load-sharing within osteoporotic human lumbar spine in compression and (3) the stabilising potential of the different spinal implants with respect to bone mineral density. A finite element model as described here may be used to predict the biomechanical behaviour of the spine. Moreover, the influence of different spinal stabilisation systems may be predicted.

High temperature components in internal combustion engines and exhaust systems must withstand severe mechanical and thermal cyclic loads throughout their lifetime. The combination of thermal transients and mechanical load cycling results in a complex evolution of damage, leading to thermomechanical fatigue (TMF) of the material. Analytical tools are increasingly employed by designers and engineers for component durability assessment well before any hardware testing. The DTMF model for TMF life prediction, which assumes that micro-crack growth is the dominant damage mechanism, is capable of providing reliable predictions for a wide range of high-temperature components and materials in internal combustion engines. Thus far, the DTMF model has employed a local approach where surface stresses, strains, and temperatures are used to compute damage for estimating the number of cycles for a small initial defect or micro-crack to reach a critical length. In the presence of significant gradients of stresses, strains, and temperatures, the use of surface field values could lead to very conservative estimates of TMF life when compared with reported lives from hardware testing. As an approximation of gradient effects, a non-local approach of the DTMF model is applied. This approach considers through-thickness fields where the micro-crack growth law is integrated through the thickness considering these variable fields. With the help of software tools, this method is automated and applied to components with complex geometries and fields. It is shown, for the TMF life prediction of a turbocharger housing, that the gradient correction using the non-local approach leads to more realistic life predictions and can distinguish between surface cracks that may arrest or propagate through the thickness and lead to component failure.

Uptakes of 9.2 mmol g−1 (40.5 wt %) for CO2 at 273 K/0.1 MPa and 15.23 mmol g−1 (3.07 wt %) for H2 at 77 K/0.1 MPa are among the highest reported for metal–organic frameworks (MOFs) and are found for a novel, highly microporous copper‐based MOF (see picture; Cu turquoise, O red, N blue). Thermal analyses show a stability of the flexible framework up to 250 °C. Metal–organic frameworks (MOFs) as highly porous materials have gained increasing interest because of their distinct adsorption properties.1–3 They exhibit a high potential for applications in gas separation and storage,4 as sensors5 as well as in heterogeneous catalysis.6 In the last few years, the H2 storage capacity of MOFs has been considerably increased. Mesoporous MOFs show high adsorption capacities for CH4, CO2, and H2 at high pressures.2, 3, 7–10 To increase the uptake of H2 and CO2 by physisorption at ambient pressure, adsorbents with small micropores as well as high specific surface areas and micropore volumes are required.11, 12 Such microporous materials seem to be more appropriate for gas‐mixture separation by physisorption than mesoporous materials. For gas separation in MOFs the interactions between the fluid adsorptive and “open metal sites” (coordinatively unsaturated binding sites) or the ligands are regarded as important.13 Industrial processes, such as natural‐gas purification or biogas upgrading, can be improved with those materials during a vapor‐pressure swing adsorption cycle (VPSA cycle) or a temperature swing adsorption cycle (TSA cycle).14 The microporous MOF series CPO‐27‐M (M=Mg, Co, Ni, Zn), for example, shows very high CO2 uptakes at low pressures (<0.1 MPa).15, 16 Concerning H2 adsorption, the microporous MOF PCN‐12 offers with 3.05 wt % the highest uptake at ambient pressure and 77 K reported to date.17 Herein, we present a novel microporous copper‐based MOF equation image[Cu(Me‐4py‐trz‐ia)] (1; Me‐4py‐trz‐ia2−=5‐(3‐methyl‐5‐(pyridin‐4‐yl)‐4H‐1,2,4‐triazol‐4‐yl)isophthalate) with extraordinarily high CO2 and H2 uptakes at ambient pressure, the H2 uptake being similar to that in PCN‐12. The ligand Me‐4py‐trz‐ia2−, which can be obtained from cheap starting materials by a three‐step synthesis in good yield, combines carboxylate, triazole, and pyridine functions and is adopted from a recently presented series of linkers,18 for which up to now only a few coordination polymers are known.

The NaSiO Institute (Institute for Sustainable Silicate Research in Offenburg, https://inasio.hs-offenburg.de/) has been working for years on climate-friendly alternatives to insulation materials and inorganic binders, as well as the reasonable use of construction waste in the building industry. The aim of research is to realize the enormous CO 2 saving potential of the construction sector worldwide. A stopping of climate heating will only succeed if these climate-friendly alternatives are used in the construction industry. This is the only way to realize the enormous CO2 savings that will be needed in future to comply with the Paris Agreement.

Melamine (1,3,5-triazine-2,4,6-triamine or cyanuramide, C3H6N6) is a trimer of cyanamide, with a 1,3,5-triazine skeleton (Figure 3.5-1). The molecule contains 66% nitrogen by mass and, if mixed with resins, has fire retardant properties due to its release of nitrogen gas when burned or charred. The word melamine (from German) is a combination of the word melam (which is a distillation derivative of ammonium thiocyanate) and amine [1]. Melamine is also a metabolite of cyromazine, an insecticide in which the proton of an NH2-group is substituted by a cyclopropyl group.

An algorithm is presented that has successfully been utilized in practice for several years. It improves data analysis in chromatography. The program runs in an extremely reliable way and evaluates chromatographic raw data with an acceptable error. The algorithm requires a minimum of preliminaries and integrates even unsmoothed noisy data correctly.

The newly synthesized Zn4O-based MOF 3∞[Zn4(μ4-O){(Metrz-pba)2mPh}3]·8 DMF (1·8 DMF) of rare tungsten carbide (acs) topology exhibits a porosity of 43% and remarkably high thermal stability up to 430 °C. Single crystal X-ray structure analyses could be performed using as-synthesized as well as desolvated crystals. Besides the solvothermal synthesis of single crystals a scalable synthesis of microcrystalline material of the MOF is reported. Combined TG-MS and solid state NMR measurements reveal the presence of mobile DMF molecules in the pore system of the framework. Adsorption measurements confirm that the pore structure is fully accessible for nitrogen molecules at 77 K. The adsorptive pore volume of 0.41 cm3 g−1 correlates well with the pore volume of 0.43 cm3 g−1 estimated from the single crystal structure.

This paper describes a simple and fast thin layer chromatography (TLC) method for the monitoring of the relatively new intense sweetener Sucralose® in various food matrices. The method requires little or no sample preparation to isolate or concentrate the analyte. The Sucralose® extract is separated on amino‐TLC‐plates, and the analyte is derivatized “reagent‐free” by heating the developed plate for 20 min at 190°C. Spots can be measured either in the absorption or fluorescence mode. The method allows the determination of Sucralose® at the levels of interest regarding foreseen European legislation (>50 mg/kg) with excellent repeatability (RSD = 3.4%) and recovery data (95%).

We present a video-densitometric quantification method for the triazine herbicides atraton, terbumeton, simazine, atrazine, and terbutylazine. Triazine herbicides were separated on silica gel using methyl-t-butyl ether, cyclohexane (1 + 1, v/v) as mobile phase. The quantification is based on a derivation reaction using chlorine and starch-iodine which forms red-brown triazine zones. Measurements were carried out using a 16 bit ST-1603ME CCD camera with 1.56 megapixel from Santa Barbara Instrument Group, Inc., Santa Barbara, USA. A white LED was used for illumination purposes. The range of linearity covers two magnitudes using the (1/R-1) expression data transformation. The signal-to-noise ratio increases directly linearly with the measurement time. The separation method is cheap, fast and reliable.

Hot work tools are subjected to complex thermal and mechanical loads during hot forming processes. Locally, the stresses can exceed the material’s yield strength in highly loaded areas as e.g. in small radii in die cavities. To sustain the high loads, the hot forming tools are typically made of martensitic hot work steels. While temperatures for annealing of the tool steels usually lie in the range between 400 and 600 °C, the steels may experience even higher temperatures during hot forming, resulting in softening of the material due to coarsening of strengthening particles. In this paper, a temperature dependent cyclic plasticity model for the martensitic hot work tool steel 1.2367 (X38CrMoV5-3) is presented that includes softening due to particle coarsening and that can be applied in finite-element calculations to assess the effect of softening on the thermomechanical fatigue life of hot work tools. To this end, a kinetic model for the evolution of the mean size of secondary carbides based on Ostwald ripening is coupled with a cyclic plasticity model with kinematic hardening. Mechanism-based relations are developed to describe the dependency of the mechanical properties on carbide size and temperature. The material properties of the mechanical and kinetic model are determined on the basis of tempering hardness curves as well as monotonic and cyclic tests.

We present a densitometric quantification method for triclosan in toothpaste, separated by high-performance thin-layer chromatography (HPTLC) and using a 48-bit flatbed scanner as the detection system. The sample was band-wise applied to HPTLC plates (10 × 20 cm), with fluorescent dye, Merck, Germany (1.05554). The plates were developed in a vertical developing chamber with 20 min of chamber saturation over 70 mm, using n-heptane–methyl tert-butyl ether–acetic acid (92:8:0.1, V/V) as solvent. The RF value of triclosan is hRF = 22.4, and quantification is based on direct measurements using an inexpensive 48-bit flatbed scanner for color measurements (in red, green, and blue) after plate staining with 2,6-dichloroquinone-4-chloroimide (Gibbs' reagent). Evaluation of the red channel makes the measurements of triclosan very specific. For linearization, an extended Kubelka–Munk expression was used for data transformation. The range of linearity covers more than two orders of magnitude and is between 91 and 1000 ng. The separation method is inexpensive, fast and reliable.

In dieser Arbeit werden die außentemperaturgeführte Vorlauftemperaturregelung (Standard-TABS-Strategie), ein Verfahren das auf einer multiplen linearen Regression basiert (AMLR-Strategie) und ein Verfahren, das unter dem Obergriff der modellprädiktiven Regelung (MPC-Strategie) zusammengefasst werden kann, untersucht. Anhand der Simulationsergebnisse und des Integrationsaufwandes in die Gebäudeautomation des Seminargebäudes wurde eine Fokussierung auf die AMLR-Strategie vorgenommen.