A semi‐analytical curved element for linear elasticity based on the scaled boundary finite element method

This work introduces a semi‐analytical formulation for the simulation and modeling of curved structures based on the scaled boundary finite element method (SBFEM). This approach adapts the fundamental idea of the SBFEM concept to scale a boundary to describe a geometry. Until now, scaling in SBFEM has exclusively been performed along a straight coordinate that enlarges, shrinks, or shifts a given boundary. In this novel approach, scaling is based on a polar or cylindrical coordinate system such that a boundary is shifted along a curved scaling direction. The derived formulations are used to compute the static and dynamic stiffness matrices of homogeneous curved structures. The resulting elements can be coupled to general SBFEM or FEM domains. For elastodynamic problems, computations are performed in the frequency domain. Results of this work are validated using the global matrix method and standard finite element analysis. Copyright © 2016 John Wiley & Sons, Ltd.     

Intracellular uptake and inhibitory activity of aromatic fluorinated amino acids in human breast cancer cells

Nonproteinogenic amino acids that either occur naturally or are synthesized chemically are becoming important tools in modern drug discovery. In this context, fluorinated amino acids have great potential in the development of novel pharmaceuticals and drugs. To assess whether different fluorinated aromatic amino acid analogues of phenylalanine, tyrosine, and tryptophan are potentially interesting as therapeutic drugs, we examined their cytostatic and cytotoxic effects on the growth of the human breast cancer cell line MCF-7. Of all the tested analogues L-4-fluorotryptophan, L-6-fluorotryptophan and L-p-fluorophenylalanine effectively and irreversibly inhibited cell growth with IC(50) values in the low micromolar range (3-15 microM). Additionally, using L-4-[14C]fluorotryptophan, and L-6-[14C]fluorotryptophan, we discovered that the cellular uptake of these fluorinated amino acids occurs through active transport with a 70-fold excess of intracellular over extracellular concentrations. We identified system L as the responsible amino acid transporter. Our findings fully support the idea that fluorinated aromatic amino acid analogues are promising chemotherapeutics with the potential for use in combination with classical cancer therapy, and as new cytotoxic drugs for certain tumor types such as melanoma.     

Decrease in tensile strength and in mass of burning wood

Changes in ultimate tensile strength and mass (weight) of burning redwood were measured, and a correlation between the ultimate tensile strength and mass loss was developed. A simple model was employed for calculating the mass loss. The accuracy of this model was assessed by comparing calculated mass loss values to the data.     

An enzyme-based extraction process for the purification and enrichment of vegetable proteins to be applied in bakery products

In the current study an efficient aqueous extraction procedure using glucoamylase was developed to produce food grade protein extracts from lentils and white beans. The extracts contained 50.3 ± 0.6 and 49.2 ± 0.05 g protein per 100 g dry extract, respectively. The nutritional value of lentil and white bean protein extracts proved to be satisfying according to the amino acid composition, where methionine was the limiting amino acid. The produced extracts were tested for their technological properties. Both lentil and white bean protein extracts showed similar or even better technological properties regarding foaming and emulsifying capacities, heat stability and gelling properties compared to soy and pea protein extracts. Food application tests in white bread, pound cake and sponge cake proved lentil and white bean protein extracts to be potential alternatives to soy protein in replacing proteins from animal origin.     

Combinatorial Alloy Design by Laser Additive Manufacturing

The authors uses laser additive manufacturing (LAM) as a combinatorial method for synthesizing microstructurally and compositionally piecewise graded bulk alloys. Authors fabricate blocks consisting of a sequence of ≈500 μm thick tool steel layers, each with different chemical composition, by laser metal deposition where alloy powders are deposited layer‐wise on a substrate. The reference materials are a Cr–Mo–V hot working tool steel and a Ni‐based maraging steel. The layers between them consist of corresponding blends of the two materials with varying composition from layer to layer (alloy volume fractions 80:20, 60:40, 40:60, and 20:80). The bulk alloy is hot rolled and heat treated. Subsequently each layer is characterized for microstructure, chemical composition and mechanical properties using electron back scatter diffraction, tensile testing, and indentation. The approach is an efficient high‐throughput method enabling rapid probing of novel compositional alloy blends. It can be applied for finding new alloys both, by LAM and for LAM. For the tool steel blends synthesized here, authors observe that the Cr–Mo–V tool steel, when mixed with the Ni‐base maraging steel, can be continuously tuned for a strength‐ductility profile in the range of 800–1650 MPa strength and 15–25% tensile elongation.     

Rheooptical investigations of shear-induced aggregation of polymers in dilute solutions

The phenomenon of shear-induced aggregation has been investigated in dilute solutions of high molar mass polystyrene standards in phthalic acid esters by light scattering and simultaneous rheometrical measurements. An optical-rheological correlation is found which can easily be understood by simple molecular kinetic models. Systematic examination of the polymer solutions, varying temperature, concentration, and molar mass, shows a dependence of the aggregation on these parameters which fits thermodynamic models. Received: 3 November 1997/Revised version: 16 December 1997/Accepted: 18 December 1997     

System-defined design and performance of RFICs for W-CDMA mobile radio terminals

Third generation wideband CDMA (W-CDMA) systems like UMTS will add broad-band data to support video, Internet access, and other high speed services for untethered devices. They are currently deployed in Japan and will be introduced in Europe in 2002. Despite sufficient RF performance has been assumed in the standardization bodies, especially in mobile devices the RF part is still a limiting factor for the overall system characteristics. Only an integral design approach including both RF and baseband functionalities makes it possible to achieve analog front-ends with sufficient performance. This paper reviews transceiver architectures with respect to W-CDMA and presents some of the recent silicon-based radio frequency integrated circuits for mobile terminals.     

Traglastberechnung unterspannter Träger

Ultimate limit loads of externally reinforced beams. For practical purpose the 3‐dimensional stability problem of an externally reinforced beam is often reduced to a plane model. This paper however is based on a geometrically nonlinear analysis by second order theory using the 3‐dimensional model. The results of both methods are compared. Furthermore the sensibility of those systems to a variation of the essential influences on the ultimate limit loads are studied based on exemplary parameter variation.     

15. DASt‐Forschungskolloquium Stahlbau

15. DASt‐research‐colloquium steel construction. The German association of steel construction (DASt) regularly holds a colloquium on actual research topics in the field of steel construction. This event is a kind of a PhD symposium where young researchers have the possibility to present and discuss their actual research activities and results. The colloquium mainly addresses to practical engineers, people of administrations and other young research engineers with the aim to inform about the current stage of steel research in Germany. The 15. DASt‐research‐colloquium was held at the University of Stuttgart on 1. and 2. April. Within this colloquium it was the first time possible to award three of the 20 speakers with prices for their best presentations. This contribution thus includes, beside an general overwiew on the 15. DASt‐research‐colloquium a short summary of each of the three awarded presentations.