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Is part of the Bibliography
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Successful optimization requires an appropriate model of the system under consideration. When selecting a suitable level of detail, one has to consider solution quality as well as the computational and implementation effort. In this paper, we present a MINLP for a pumping system for the drinking water supply of high-rise buildings. We investigate the influence of the granularity of the underlying physical models on the solution quality. Therefore, we model the system with a varying level of detail regarding the friction losses, and conduct an experimental validation of our model on a modular test rig. Furthermore, we investigate the computational effort and show that it can be reduced by the integration of domain-specific knowledge.
α-hydroxy ketones (HK) and 1,2-diols are important building blocks for fine chemical synthesis. Here, we describe the R-selective 2,3-butanediol dehydrogenase from B. clausii DSM 8716ᵀ (BcBDH) that belongs to the metal-dependent medium chain dehydrogenases/reductases family (MDR) and catalyzes the selective asymmetric reduction of prochiral 1,2-diketones to the corresponding HK and, in some cases, the reduction of the same to the corresponding 1,2-diols. Aliphatic diketones, like 2,3-pentanedione, 2,3-hexanedione, 5-methyl-2,3-hexanedione, 3,4-hexanedione and 2,3-heptanedione are well transformed. In addition, surprisingly alkyl phenyl dicarbonyls, like 2-hydroxy-1-phenylpropan-1-one and phenylglyoxal are accepted, whereas their derivatives with two phenyl groups are not substrates. Supplementation of Mn²⁺ (1 mM) increases BcBDH's activity in biotransformations. Furthermore, the biocatalytic reduction of 5-methyl-2,3-hexanedione to mainly 5-methyl-3-hydroxy-2-hexanone with only small amounts of 5-methyl-2-hydroxy-3-hexanone within an enzyme membrane reactor is demonstrated.
The enantioselective synthesis of α-hydroxy ketones and vicinal diols is an intriguing field because of the broad applicability of these molecules. Although, butandiol dehydrogenases are known to play a key role in the production of 2,3-butandiol, their potential as biocatalysts is still not well studied. Here, we investigate the biocatalytic properties of the meso-butanediol dehydrogenase from Bacillus licheniformis DSM 13T (BlBDH). The encoding gene was cloned with an N-terminal StrepII-tag and recombinantly overexpressed in E. coli. BlBDH is highly active towards several non-physiological diketones and α-hydroxyketones with varying aliphatic chain lengths or even containing phenyl moieties. By adjusting the reaction parameters in biotransformations the formation of either the α-hydroxyketone intermediate or the diol can be controlled.
The application of atomic layer deposition in the production of sorbents for ⁹⁹Mo/⁹⁹ᵐTc generator
(2020)
New production routes for ⁹⁹Mo are steadily gaining importance. However, the obtained specific activity is much lower than currently produced by the fission of U-235. To be able to supply hospitals with ⁹⁹Mo/⁹⁹ᵐTc generators with the desired activity, the adsorption capacity of the column material should be increased. In this paper we have investigated whether the gas phase coating technique Atomic Layer Deposition (ALD), which can deposit ultra-thin layers on high surface area materials, can be used to attain materials with high adsorption capacity for ⁹⁹Mo. For this purpose, ALD was applied on a silica-core sorbent material to coat it with a thin layer of alumina. This sorbent material shows to have a maximum adsorption capacity of 120 mg/g and has a ⁹⁹ᵐTc elution efficiency of 55 ± 2% based on 3 executive elutions.
Exercise training effectively mitigates aging-induced health and fitness impairments. Traditional training recommendations for the elderly focus separately on relevant physiological fitness domains, such as balance, flexibility, strength and endurance. Thus, a more holistic and functional training framework is needed. The proposed agility training concept integratively tackles spatial orientation, stop and go, balance and strength. The presented protocol aims at introducing a two-armed, one-year randomized controlled trial, evaluating the effects of this concept on neuromuscular, cardiovascular, cognitive and psychosocial health outcomes in healthy older adults. Eighty-five participants were enrolled in this ongoing trial. Seventy-nine participants completed baseline testing and were block-randomized to the agility training group or the inactive control group. All participants undergo pre- and post-testing with interim assessment after six months. The intervention group currently receives supervised, group-based agility training twice a week over one year, with progressively demanding perceptual, cognitive and physical exercises. Knee extension strength, reactive balance, dual task gait speed and the Agility Challenge for the Elderly (ACE) serve as primary endpoints and neuromuscular, cognitive, cardiovascular, and psychosocial meassures serve as surrogate secondary outcomes. Our protocol promotes a comprehensive exercise training concept for older adults, that might facilitate stakeholders in health and exercise to stimulate relevant health outcomes without relying on excessively time-consuming physical activity recommendations.
Multi-enzyme immobilization onto a capacitive field-effect biosensor by nano-spotting technique is presented. The nano-spotting technique allows to immobilize different enzymes simultaneously on the sensor surface with high spatial resolution without additional photolithographical patterning. The amount of applied enzymatic cocktail on the sensor surface can be tailored. Capacitive electrolyte-insulator-semiconductor (EIS) field-effect sensors with Ta2O5 as pH-sensitive transducer layer have been chosen to immobilize the three different (pL droplets) enzymes penicillinase, urease, and glucose oxidase. Nano-spotting immobilization is compared to conventional drop-coating method by defining different geometrical layouts on the sensor surface (fully, half-, and quarter-spotted). The drop diameter is varying between 84 µm and 102 µm, depending on the number of applied drops (1 to 4) per spot. For multi-analyte detection, penicillinase and urease are simultaneously nano-spotted on the EIS sensor. Sensor characterization was performed by C/V (capacitance/voltage) and ConCap (constant capacitance) measurements. Average penicillin, glucose, and urea sensitivities for the spotted enzymes were 81.7 mV/dec, 40.5 mV/dec, and 68.9 mV/dec, respectively.
Seismic behavior of an existing unreinforced masonry building built pre-modern code, located in the City of Ohrid, Republic of North Macedonia has been investigated in this paper. The analyzed school building is selected as an archetype in an ongoing project named “Seismic vulnerability assessment of existing masonry structures in Republic of North Macedonia (SeismoWall)”. Two independent segments were included in this research: Seismic hazard assessment by creating a cite specific response spectra and Seismic vulnerability definition by creating a region - specific series of vulnerability curves for the chosen building topology. A reliable Seismic Hazard Assessment for a selected region is a crucial point for performing a seismic risk analysis of a characteristic building class. In that manner, a scenario – based method that incorporates together the knowledge of tectonic style of the considered region, the active fault characterization, the earth crust model and the historical seismicity named Neo Deterministic approach is used for calculation of the response spectra for the location of the building. Variations of the rupturing process are taken into account in the nucleation point of the rupture, in the rupture velocity pattern and in the istribution of the slip on the fault. The results obtained from the multiple scenarios are obtained as an envelope of the response spectra computed for the cite using the procedure Maximum Credible Seismic Input (MCSI). Capacity of the selected building has been determined by using nonlinear static analysis. MINEA software (SDA Engineering) was used for verification of the structural safety of the chosen unreinforced masonry structure. In the process of optimization of the number of samples, computational cost required in a Monte Carlo simulation is significantly reduced since the simulation is performed on a polynomial response surface function for prediction of the structural response. Performance point, found as the intersection of the capacity of the building and the spectra used, is chosen as a response parameter. Five levels of damage limit states based on the capacity curve of the building are defined in dependency on the yield displacement and the maximum displacement. Maximum likelihood estimation procedure is utilized in the process of vulnerability curves determination. As a result, region specific series of vulnerability curves for the chosen type of masonry structures are defined. The obtained probabilities of exceedance a specific damage states as a result from vulnerability curves are compared with the observed damages happened after the earthquake in July 2017 in the City of Ohrid, North Macedonia.
A further development of the Added-Mass-Method allows the combined representation of the effects of both soil-structure-interaction and fluid-structure interaction on a liquid-filled-tank in one model. This results in a practical method for describing the dynamic fluid pressure on the tank shell during joint movement. The fluid pressure is calculated on the basis of the tank's eigenform and the earthquake acceleration and represented by additional masses on the shell. The bearing on compliant ground is represented by replacement springs, which are calculated dependent on the local soil composition. The influence of the shear modulus of the compliant soil is clearly visible in the pressure curves and the stress distribution in the shell. The acceleration spectra are also dependent on soil stiffness. According to Eurocode-8 the acceleration spectra are determined for fixed soil-classes, instead of calculating the accelerations for each site in direct dependence on the soil composition. This leads to unrealistic sudden changes in the system's response. Therefore, earthquake spectra are calculated for different soil models in direct dependence of the shear modulus. Thus, both the acceleration spectra and the replacement springs match the soil composition. This enables a reasonable and consistent calculation of the system response for the actual conditions at each site.
Transport through Redox-Active Ru-Terpyridine Complexes Integrated in Single Nanoparticle Devices
(2020)
Transition metal complexes are electrofunctional molecules due to their high conductivity and their intrinsic switching ability involving a metal-to-ligand charge transfer. Here, a method is presented to contact reliably a few to single redox-active Ru-terpyridine complexes in a CMOS compatible nanodevice and preserve their electrical functionality. Using hybrid materials from 14 nm gold nanoparticles (AuNP) and bis-{4′-[4-(mercaptophenyl)-2,2′:6′,2″-terpyridine]}-ruthenium(II) complexes a device size of 30² nm² inclusive nanoelectrodes is achieved. Moreover, this method bears the opportunity for further downscaling. The Ru-complex AuNP devices show symmetric and asymmetric current versus voltage curves with a hysteretic characteristic in two well separated conductance ranges. By theoretical approximations based on the single-channel Landauer model, the charge transport through the formed double-barrier tunnel junction is thoroughly analyzed and its sensibility to the molecule/metal contact is revealed. It can be verified that tunneling transport through the HOMO is the main transport mechanism while decoherent hopping transport is present to a minor extent.
The chemical industry is one of the most important industrial sectors in Germany in terms of manufacturing revenue. While thermodynamic boundary conditions often restrict the scope for reducing the energy consumption of core processes, secondary processes such as cooling offer scope for energy optimisation. In this contribution, we therefore model and optimise an existing cooling system. The technical boundary conditions of the model are provided by the operators, the German chemical company BASF SE. In order to systematically evaluate different degrees of freedom in topology and operation, we formulate and solve a Mixed-Integer Nonlinear Program (MINLP), and compare our optimisation results with the existing system.
We generalize our work on Carlitz prime power torsion extension to torsion extensions of Drinfeld modules of arbitrary rank. As in the Carlitz case, we give a description of these extensions in terms of evaluations of Anderson generating functions and their hyperderivatives at roots of unity. We also give a direct proof that the image of the Galois representation attached to the p-adic Tate module lies in the p-adic points of the motivic Galois group. This is a generalization of the corresponding result of Chang and Papanikolas for the t-adic case.
There is a very large number of very important situations which can be modeled with nonlinear parabolic partial differential equations (PDEs) in several dimensions. In general, these PDEs can be solved by discretizing in the spatial variables and transforming them into huge systems of ordinary differential equations (ODEs), which are very stiff. Therefore, standard explicit methods require a large number of iterations to solve stiff problems. But implicit schemes are computationally very expensive when solving huge systems of nonlinear ODEs. Several families of Extrapolated Stabilized Explicit Runge-Kutta schemes (ESERK) with different order of accuracy (3 to 6) are derived and analyzed in this work. They are explicit methods, with stability regions extended, along the negative real semi-axis, quadratically with respect to the number of stages s, hence they can be considered to solve stiff problems much faster than traditional explicit schemes. Additionally, they allow the adaptation of the step length easily with a very small cost.
Two new families of ESERK schemes (ESERK3 and ESERK6) are derived, and analyzed, in this work. Each family has more than 50 new schemes, with up to 84.000 stages in the case of ESERK6. For the first time, we also parallelized all these new variable step length and variable number of stages algorithms (ESERK3, ESERK4, ESERK5, and ESERK6). These parallelized strategies allow to decrease times significantly, as it is discussed and also shown numerically in two problems. Thus, the new codes provide very good results compared to other well-known ODE solvers. Finally, a new strategy is proposed to increase the efficiency of these schemes, and it is discussed the idea of combining ESERK families in one code, because typically, stiff problems have different zones and according to them and the requested tolerance the optimum order of convergence is different.
Masonry is used in many buildings not only for load-bearing walls, but also for non-load-bearing enclosure elements in the form of infill walls. Many studies confirmed that infill walls interact with the surrounding reinforced concrete frame, thus changing dynamic characteristics of the structure. Consequently, masonry infills cannot be neglected in the design process. However, although the relevant standards contain requirements for infill walls, they do not describe how these requirements are to be met concretely. This leads in practice to the fact that the infill walls are neither dimensioned nor constructed correctly. The evidence of this fact is confirmed by the recent earthquakes, which have led to enormous damages, sometimes followed by the total collapse of buildings and loss of human lives. Recently, the increasing effort has been dedicated to the approach of decoupling of masonry infills from the frame elements by introducing the gap in between. This helps in removing the interaction between infills and frame, but raises the question of out-of-plane stability of the panel. This paper presents the results of the experimental campaign showing the out-of-plane behavior of masonry infills decoupled with the system called INODIS (Innovative decoupled infill system), developed within the European project INSYSME (Innovative Systems for Earthquake Resistant Masonry Enclosures in Reinforced Concrete Buildings). Full scale specimens were subjected to the different loading conditions and combinations of in-plane and out-of-plane loading. Out-of-plane capacity of the masonry infills with the INODIS system is compared with traditionally constructed infills, showing that INODIS system provides reliable out-of-plane connection under various loading conditions. In contrast, traditional infills performed very poor in the case of combined and simultaneously applied in-plane and out-of-plane loading, experiencing brittle behavior under small in-plane drifts followed by high out-of-plane displacements. Decoupled infills with the INODIS system have remained stable under out-of-plane loads, even after reaching high in-plane drifts and being damaged.
Reinforced concrete (RC) structures with masonry infills are widely used for several types of buildings all over the world. However, it is well known that traditional masonry infills constructed with rigid contact to the surrounding RC frame performed rather poor in past earthquakes. Masonry infills showed severe in-plane damages and failed in many cases under out-of-plane seismic loading. As the undesired interactions between frames and infills changes the load transfer on building level, complete collapses of buildings were observed. A possible solution is uncoupling of masonry infills to the frame to reduce the infill contribution activated by the frame deformation under horizontal loading. The paper presents numerical simulations on RC frames equipped with the innovative decoupling system INODIS. The system was developed within the European project INSYSME and allows an effective uncoupling of frame and infill. The simulations are carried out with a micro-modelling approach, which is able to predict the complex nonlinear behaviour resulting from the different materials and their interaction. Each brick is modelled individually and connected taking into account nonlinearity of a brick mortar interface. The calibration of the model is based on small specimen tests and experimental results for one bay one storey frame are used for the validation. The validated model is further used for parametric studies on two storey and two bay infilled frames. The response and change of the structural stiffness are analysed and compared to the traditionally infilled frame. The results confirm the effectiveness of the INODIS system with less damage and relatively low contribution of the infill at high drift levels. In contrast to the uncoupled system configurations, traditionally infilled frames experienced brittle failure at rather low drift levels.
Biocomposite Materials Based on Carbonized Rice Husk in Biomedicine and Environmental Applications
(2020)
This chapter describes the prospects for biomedical and environmental engineering applications of heterogeneous materials based on nanostructured carbonized rice husk. Efforts in engineering enzymology are focused on the following directions: development and optimization of immobilization methods leading to novel biotechnological and biomedical applications; construction of biocomposite materials based on individual enzymes, multi-enzyme complexes and whole cells, targeted on realization of specific industrial processes. Molecular biological and biochemical studies on cell adhesion focus predominantly on identification, isolation and structural analysis of attachment-responsible biological molecules and their genetic determinants. The chapter provides a short overview of applications of the biocomposite materials based of nanostructured carbonized adsorbents. It emphasizes that further studies and better understanding of the interactions between CNS and microbial cells are necessary. The future use of living cells as biocatalysts, especially in the environmental field, needs more systematic investigations of the microbial adsorption phenomenon.
Water suppliers are faced with the great challenge of achieving high-quality and, at the same time, low-cost water supply. Since climatic and demographic influences will pose further challenges in the future, the resilience enhancement of water distribution systems (WDS), i.e. the enhancement of their capability to withstand and recover from disturbances, has been in particular focus recently. To assess the resilience of WDS, graph-theoretical metrics have been proposed. In this study, a promising approach is first physically derived analytically and then applied to assess the resilience of the WDS for a district in a major German City. The topology based resilience index computed for every consumer node takes into consideration the resistance of the best supply path as well as alternative supply paths. This resistance of a supply path is derived to be the dimensionless pressure loss in the pipes making up the path. The conducted analysis of a present WDS provides insight into the process of actively influencing the resilience of WDS locally and globally by adding pipes. The study shows that especially pipes added close to the reservoirs and main branching points in the WDS result in a high resilience enhancement of the overall WDS.
Water distribution systems are an essential supply infrastructure for cities. Given that climatic and demographic influences will pose further challenges for these infrastructures in the future, the resilience of water supply systems, i.e. their ability to withstand and recover from disruptions, has recently become a subject of research. To assess the resilience of a WDS, different graph-theoretical approaches exist. Next to general metrics characterizing the network topology, also hydraulic and technical restrictions have to be taken into account. In this work, the resilience of an exemplary water distribution network of a major German city is assessed, and a Mixed-Integer Program is presented which allows to assess the impact of capacity adaptations on its resilience.