A fast spatial-domain method for the suppression ofexcitation-induced spurious modes in SCN TLM

An efficient method for the suppression of excitation-induced spurious modes in the symmetrical condensed node (SCN) transmission-line matrix (TLM) method is presented for the general case of dielectric, anisotropic, or lossy media in planar structures. A special mapping of the field-excitation onto the wave amplitudes of the TLM algorithm completely prevents the emanation of the spurious modes. The application of the mapping in the k-ω space can be done for waveguides with low computational effort. The method is generalized for planar structures with high spatial frequencies of the field at the discontinuities. We use precomputed field templates at the entrance of the three-dimensional (3-D) structures. The mapping is mainly done in the space domain based on the quasi-TEM propagation of the guided waves to keep the computational effort low. Instead of the four-dimensional (4-D) k-ω transformation, only independent one-dimensional (1-D) transformations to the wave coefficient of the conductors direction and ω are necessary. In the case of propagation with low dispersion, the expenditure can be further reduced to 1-D transformations with respect to ω. The efficiency of the present method is demonstrated by investigation of a coplanar waveguide and a triplate waveguide     

A wireless data link for mobile applications

A short overview is given on wireless high speed data links for local-area-ad-hoc-networks in mobile applications and a multifunctional CDMA-Direct-Sequence Spread-Spectrum communicating platform is investigated which may be used for inter vehicle communication as well as for object detection and ranging in the environment of cars.     

Multi antenna scanning

A low-cost method for improving mobile FM reception is discussed. The problem suffered by FM in a moving car is the sporadic distortion of reception due to multipath propagation. Improvement can be obtained by multi antenna diversity system because the probability of simultaneous distortion on all antennas is greatly reduced as the number of antennas increases     

A novel method to measure both the reductive and the radical scavenging activity in a linoleic acid model system

The aim of this study was to develop a combined method for measuring the total antioxidant activity, the reductive and the radical scavenging activity. Linoleic acid was used as the substrate for an iron-initiated lipid peroxidation to measure the total antioxidant activity. In addition, methyl esters of linoleic acid hydroperoxides were used as substrates to measure the reductive antioxidant activity. The radical scavenging antioxidant activity was calculated by subtracting the reductive antioxidative activity from the total antioxidative activity. As representative examples, the antioxidants alpha-tocopherol, ascorbic acid, trans-resveratrol and L-glutathione as well as commonly used food additives such as 2(3)-tert-butyl-4-hydroxyanisole (BHA) and 2,6-bis(1,1-dimethylethyl)-4-methylphenol (BHT) were analyzed. The results for the novel antioxidation test showed that alpha-tocopherol, BHA and BHT are primarily acting as radical scavengers, whereas ascorbic acid and L-glutathione show a strong reductive capacity. As linoleic acid as well as its hydroperoxides both are present in foods and in the organism, the test presented here can be considered representative of radical reactions occurring in food matrixes and in vivo. Further experiments are required to document the comprehensive applicability in foods and in vivo.     

Joint building ventures as a new instrument for urban development: a qualitative analysis of Baugruppen in Freiburg,Germany

Abstract

This article reviews a special type of collaborative housing that has emerged in the German housing market in response to the growing need for urban housing and increasing focus on active and networking housing communities and stable neighbourhoods. Joint building ventures are projects in which private individuals jointly establish residential property. However, the academic literature on this issue is underdeveloped. To foster a better understanding of the topic, this article focuses specifically on detecting the strengths and weaknesses of this type of joint building venture and its contribution to a higher homeownership rate. The qualitative interview data were collected between December 2015 and March 2016 in Freiburg, Germany. The findings reveal perceived advantages in terms of supportive networks, customised solutions and potential cost savings, whereas the identified disadvantages are high financial risks, mutual dependencies and personal efforts. Practical implications and avenues for future research are derived.     

Hybrid space discretizing-integral equation methods for numericalmodeling of transient interference

The application of hybrid time-domain transmission line matrix (TLM)-integral equation (TLM-IE) methods is discussed. The hybrid TLM-IE methods are suited very well for the numerical modeling of the electromagnetic interaction between complex objects separated by large free-space regions. While the field inside the objects is modeled by the TLM method the electromagnetic interaction between the objects is described via Green's functions. The hybrid methods are applied to analyze the near-field coupling of two shielded enclosures. In a final discussion, the hybrid methods are compared with each other and with the pure TLM method, especially considering the computational time and storage requirement. Compared with the pure TLM method the hybrid methods require a considerably reduced computational effort     

Transistor oscillators with impedance noise matching

A theory is derived which makes it possible to predict the carrier-to-noise ratio (CNR) of a transistor oscillator with real components depending on parameters of the active element and the oscillator circuit, which can be easily measured. The theory leads to certain new ideas for low-noise oscillator design which include the use of a multiple-stage active element and an impedance condition for noise matching. In this context the conditions for the use of GaAs FETs in low-noise oscillators are investigated. The resulting possibility of predicting the CNR depending only on transistor and circuit parameters is verified experimentally with seven different single-bipolar-transistor oscillators in the frequency range around 150 MHz. The measured values of the CNR show very good agreement with the values derived from theory. The differences between measured and calculated values are smaller than the measurement uncertainty of 3 dB