Großversuch WILD‐Brücke – versuchsgestützte Bemessung einer UHPC‐Bogenbrücke

Full‐Scale Experiment Bridge WILD – Design of an UHPC Arch Bridge based on Experiments The outstanding durability of UHPC makes this material predestined for the construction of bridges. In Austria UHPC is introduced into the practice of road bridges through the realisation of the bridge WILD. The cross section of the arch, which spans 70 m, is just 6 cm thick and doesn't contain any passive reinforcement. The design is based on international recommendations on the one hand and on specific experiments on the other hand. This paper deals with the evaluation of two full‐scale laboratory tests. The setup is configured for getting a broad field of results as it is necessary for approval tests. In this way, all critical design states, which are also determined by calculation, are investigated experimentally. Furthermore, the experiments cover secondary effects, which don't have any verification through practical experience but can clearly be seen in FE‐results. The test results are carefully interpreted and explained by the use of simple mechanical models. The final examination of the results is figured out by means of comparison between calculation and experiment.     

太阳能电网——电驱动代替内燃机排放

以锂离子技术为核心的新电池系统将为电动汽车存贮更多的电能，并使被称之为“能源网络系统电动车”的设想成为可能。这个新思路或者说新系统将太阳能，风能电力系统综合到电动汽车的能源网络系统里来，在阴天或者弱风天气中为电动汽车提供电能。     

1,25-dihydroxyvitamin D3 production and vitamin D3 receptor expression are developmentally regulated during differentiation of human monocytes into macrophages

It has been well established that human mononuclear phagocytes have the capacity to produce 1,25-dihydroxy-vitamin D3 [1,25(OH)3D3] and express the vitamin D receptor (VDR). However, 1 alpha-hydroxylase activity and VDR receptor expression during differentiation of monocytes (MO) into mature macrophages (MAC) have not been previously examined. The in vitro maturation of blood MO can serve as a model for the in vivo transformation of immature blood MO into MAC. Here, when cultured in the presence of serum, MO undergo characteristic changes in morphology, antigenic phenotype, and functional activity consistent with their differentiation into MAC. We serially measured 1,25(OH)2D3 and 24,25-dihydroxyvitamin D3 [24,25(OH)2D3] synthesis, specific [3H]-1,25(OH)2D3 binding, and VDR mRNA levels during in vitro maturation of MO into MAC and correlated these functions with maturation-associated changes in the phenotype (MAX.1 and CD71) and secretory repertoire (interleukin-1 beta [IL-1 beta], neopterin) of the cells. MO showed only little conversion of 25-(OH)D3 into 1,25(OH)2D3 (1.4 +/- 0.4 pmol/10(6) cells/6 h, n = 5) that increased gradually during maturation into MAC at day 8 of culture (5.3 +/- 4.3 pmol/10(6) cells/6 h, n = 5). Interferon-gamma (IFN-gamma) increased baseline 1,25(OH)2D3-synthesis approximately twofold during all phases of differentiation. The time course of increased 1,25(OH)2D3-synthesis correlated with enhanced secretion of neopterin and expression of MAX.1 and CD71. The addition of exogenous 1,25(OH)2D3 did not influence constitutive 1,25(OH)2D3 synthesis, but IFN-gamma-stimulated production was suppressed to baseline levels. Exogenous 1,25(OH)2D3 also stimulated 24,25(OH)2D3 synthesis in freshly isolated MO (from 1.0 +/- 0.8 pmol/6 h to 5.6 +/- 0.9 pmol), whereas matured MAC showed no 24,25(OH)2D3 synthesis. Furthermore, we examined the expression of the VDR during the differentiation process. VDR mRNA and protein were constitutively expressed in MO, whereas VDR was downregulated in mature MAC on both the mRNA and protein levels. Homologous upregulation of VDR protein by 1,25(OH)2D3 occurred in MO and, to a lesser degree, in MAC. In contrast, VDR mRNA concentrations were not influenced by 1,25(OH)2D3. Taken together, our results show that MO into MAC differentiation in vitro is associated with (1) an enhanced capacity to synthesize 1,25(OH)2D3, (2) a loss of 24,25(OH)2D3-synthesizing activity, and (3) a decrease in the expression of VDR mRNA and protein. Because 1,25(OH)2D3 was shown to induce differentiation of MO into MAC, our data sugest an autoregulatory mechanism of MO/MAC generation by 1,25(OH)2D3.     

Low-cycle fatigue properties of microalloyed medium carbon precipitation hardening steels in comparison to quenched and tempered steels

Monotonic and cyclic stress strain curves and strain fatigue-life curves of a normalized carbon steel Cf 53 N, two quenched and tempered steels Ck 45 QT, 34 CrMoS 4 QT and three microalloyed medium-carbon precipitation-hardening steels 27 MnSiVS 6 + Ti BY, 38 MnSiVS 5 BY and 44 MnSiVS 6 + Ti BY, have been evaluated. Similar strain hardening was observed in the monotonic tensile tests whereas different hardening or softening was found under cyclic loading conditions. QT steels reveal pronounced cyclic softening over the entire strain range investigated, the ferritic pearlitic steels show only a slight decrease in the cyclic proof stress and cyclic hardening at larger strains. Strain fatigue-life curves result in a common scatterband of all steels investigated with the microalloyed steels 27 MnSiVS 6 + Ti BY and 44 MnSiVS 6 + Ti BY lying at the upper limit. Crack initiation probability of the microalloyed medium-carbon precipitation-hardening steels in the low-cycle fatigue range is equivalent or lower than for the normalized carbon steel and the QT-steels.     

Improved 3D Interpolation-Based Path Planning for a Fixed-Wing Unmanned Aircraft

Path planning for unmanned aircraft has attracted a remarkable amount of interest from the research community. However, planning in large environments such as the civil airspace has not been addressed extensively. In this paper we apply a heuristic incremental interpolation-based search algorithm with efficient replanning capabilities to the path planning problem for a fixed-wing aircraft operating in a natural environment to plan and re-plan long flight paths. We modified the algorithm to account for the minimum turning radius and the limited flight path angles of a fixed-wing aircraft. Additionally, we present a method to consider a desired minimum cruising altitude and a post-processing algorithm to improve the path and remove unnecessary path points. These properties specific to aircraft operation could not be addressed with the original algorithm. Simulation results show that the planner produces intuitive, short paths and is capable of exploiting previous planning efforts, when unknown obstacles are encountered.