The cross-sectional resistance of square and rectangular hollow steel sections loaded by bending moment and shear force

This paper presents an evaluation of the design rules for the bending moment–shear force (M−V) interaction of cold- and hot-formed square, and rectangular hollow steel sections (SHS &amp; RHS). More specifically, the design rules, as provided by EN1993-1-1 regarding RHS and SHS of section class 1 and 2 are covered for the steel grades S235 up to and including S460. A 4-point bending test was simulated by means of a finite element model, which was validated on the basis of experimental tests from existing literature. A parametric study was performed and numerical M−V interaction results were compared to the provisions in EN1993-1-1. This comparison indicates that the current design rules in EN1993-1-1 regarding M−V interaction are conservative and overestimate the reduction of the bending resistance due to the presence of shear. Alternative design rules for the shear area and M−V interaction of RHS and SHS are proposed and evaluated by means of a statistical assessment procedure based on existing literature and EN1990-1-1. Both newly developed design rules are shown to ensure an adequate reliability level when a partial safety factor equal to 1 is used.</p

Feasibility study on three furfurylated non-durable tropical wood species evaluated for resistance to brown, white and soft rot fungi

Furfurylation can protect non-durable wood species against biological degradation, but the method used today cannot fully protect the heartwood of Scots pine due to insufficient penetration. In order to test alternative wood substrates for furfurylation, three Malaysian grown wood species (Kelempayan, Rubberwood and Sena) were furfurylated and subjected to soil block decay testing. Their performance was compared to furfurylated Scots pine and furfurylated Beech modified using the same process. In addition, treatment characteristics were evaluated. One of the species tested, Kelempayan, seems to be a promising substrate for furfurylation. Kelempayan is easy to impregnate in both sap- and heartwood, and a 50% higher weight gain was reached using equivalent amounts of impregnation solution compared to Scots pine. Sena, Rubberwood and Beech returned weight gains 40-60% lower than Scots pine. Decay protection was largely comparable at equivalent weight percent gains for all wood species tested, although differences appeared. Generally, a weight gain of approximately 25% by furfurylation seems to offer good protection in the chosen soil block test

Cold uniform matter and neutron stars in the quark-mesons-coupling model

A new density dependent effective baryon-baryon interaction has been recently derived from the quark-meson-coupling (QMC) model, offering impressive results in application to finite nuclei and dense baryon matter. This self-consistent, relativistic quark-level approach is used to construct the Equation of State (EoS) and to calculate key properties of high density matter and cold, slowly rotating neutron stars. The results include predictions for the maximum mass of neutron star models, together with the corresponding radius and central density, as well the properties of neutron stars with mass of order 1.4 $M_\odot$. The cooling mechanism allowed by the QMC EoS is explored and the parameters relevant to slow rotation, namely the moment of inertia and the period of rotation investigated. The results of the calculation, which are found to be in good agreement with available observational data, are compared with the predictions of more traditional EoS. The QMC EoS provides cold neutron star models with maximum mass 1.9--2.1 M$_\odot$, with central density less than 6 times nuclear saturation density ($n_{0}= 0.16 {\rm fm}^{-3}$) and offers a consistent description of the stellar mass up to this density limit. In contrast with other models, QMC predicts no hyperon contribution at densities lower than $3n_0$, for matter in $\beta$-equilibrium. At higher densities, $\Xi^{-,0}$ and $\Lambda$ hyperons are present

Elevated asymmetric dimethylarginine (ADMA) and inverse correlation between circulating ADMA and glomerular filtration rate in children with sporadic focal segmental glomerulosclerosis (FSGS)

Background. Steroid-resistant nephrotic syndromes (NS) with focal and segmental glomerulosclerosis (FSGS) can be differentiated into sporadic and syndromic forms. In sporadic NS, a circulating FSGS-factor is discussed in the pathogenesis and is thought to inhibit the synthesis of nitric oxide (NO) from l-arginine by blocking the NO synthase (NOS). Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of all types of NOS. In a previous study we did not find an elevation of ADMA in a syndromic form of FSGS, the Schimke-immuno-osseous dysplasia. Here we report for the first time data on the l-arginine/NO pathway in sporadic FSGS of childhood. Methods. Nine children (5 to 18 years of age) suffering from sporadic FSGS and age-matched healthy controls were investigated. ADMA in plasma and urine as well as l-arginine in plasma were determined by gas chromatography-tandem mass spectrometry. The NO metabolites nitrate and nitrite were measured in plasma and urine by gas chromatography-mass spectrometry (GC-MS). The ADMA metabolite dimethylamine (DMA) was measured in urine by GC-MS. Results. We found elevated plasma levels of ADMA in children suffering from sporadic FSGS compared to healthy controls (851 nmol/L versus 684 nmol/L, P = 0.008). An inverse correlation between ADMA and glomerular filtration rate (GFR) was found in sporadic FSGS (Pearson's correlation coefficient −0.784, P = 0.012). Conclusion. Our study suggests that ADMA synthesis is elevated in sporadic FSGS. This finding argues for the involvement of ADMA in the pathogenesis of this disease in childhoo

Development of a mathematical model of the compact heat exchanger used for optimizing thermodynamic parameters of the aviation gas turbine engine

Nowadays, the task of using automation for improving the technical and economic efficiency of the engine by reducing the specific fuel consumption and reducing the specific weight is one of the main trends in the development of the aviation industry. A promising approach for decrement of specific fuel consumption and obtaining high thermal efficiency of the gas turbine engine (30% and above) is based on the concept of the recuperative cycle of the gas turbine engine. The article presents the computer-aided calculation of a heat exchanger for analysing the heat exchanger surface and developing the mathematical model of heat exchanger in terms of weight goodness, flow passage goodness, and optimum weight and flow passage. Design calculations had been carried out for an aircraft engine with a heat exchanger made up with deferent heat transfer surfaces. To appraise the reliability of the obtained models, the results of design calculations on the developed models have been compared with the data of other authors and with the data on the created regenerator. The obtained model focus on mathematical design calculation for optimizing the main thermodynamic parameters of a gas turbine engine coupled with a heat exchanger at the stage of conceptual design of aviation gas turbine engine with heat recovery of exhaust gas.This work was supported by the Ministry of education and science of the Russian Federation in the framework of the implementation of the Program of increasing the competitiveness of Samara University among the world's leading scientific and educational centres for 2013-2020 years

Durability testing of coconut shell according to ENV 807

Coconut shell was tested in the laboratory according to the European standard ENV 807 with three different soil types: compost soil, brown rot/soft rot rich soil and white rot/soft rot rich soil. Mass losses between 14 and 16 % were achieved with all three soils, indicating that the decay type is of little importance in the degradation process. Somewhat higher mass losses, 19-22 % were obtained for the durable/moderately durable, according to EN 350-2, wood species Sipo (Entandrophragma utile), whereas preservative-treated references had significantly lower mass losses, 0.5-7 %. The results of the test were promising but further experiments and testing will be necessary to explore the full potential for coconut shell to be used e.g. for composite materials with enhanced durability against decay fungi

Thermal Infrared Imaging Experiments of C-Type Asteroid 162173 Ryugu on Hayabusa2

The thermal infrared imager TIR onboard Hayabusa2 has been developed to investigate thermo-physical properties of C-type, near-Earth asteroid 162173 Ryugu. TIR is one of the remote science instruments on Hayabusa2 designed to understand the nature of a volatile-rich solar system small body, but it also has significant mission objectives to provide information on surface physical properties and conditions for sampling site selection as well as the assessment of safe landing operations. TIR is based on a two-dimensional uncooled micro-bolometer array inherited from the Longwave Infrared Camera LIR on Akatsuki (Fukuhara et al., 2011). TIR takes images of thermal infrared emission in 8 to 12 μm with a field of view of 16×12∘ and a spatial resolution of 0.05∘ per pixel. TIR covers the temperature range from 150 to 460 K, including the well calibrated range from 230 to 420 K. Temperature accuracy is within 2 K or better for summed images, and the relative accuracy or noise equivalent temperature difference (NETD) at each of pixels is 0.4 K or lower for the well-calibrated temperature range. TIR takes a couple of images with shutter open and closed, the corresponding dark frame, and provides a true thermal image by dark frame subtraction. Data processing involves summation of multiple images, image processing including the StarPixel compression (Hihara et al., 2014), and transfer to the data recorder in the spacecraft digital electronics (DE). We report the scientific and mission objectives of TIR, the requirements and constraints for the instrument specifications, the designed instrumentation and the pre-flight and in-flight performances of TIR, as well as its observation plan during the Hayabusa2 mission

Laboratory study of toxicity or tolerance of CCA preservative and heavy metal constituents copper, chromium and arsenic to Malaysian tropical fungi

CCA preservative and its constituent heavy metal tolerance and toxicity to 3 Malaysian isolates Phialophora fastigiata (soft rot fungus), Paecilomyces variotii (mould fungus) and an unidentified white rot Basidiomycete, was investigated by the modified ‘Strange-Smith’ agarwell- plate technique with 1.6% CCA concentration and the malt-agar-plate bioassay technique with a range of CCA and constituent metal salt concentrations of 0.0024 – 5%m/m. Daily linear hyphal extension was measured between 6 and 22 days depending on relative fungal growth rates. The slow growing Phialophora fastigiata sustained mean daily hyphal growth (mm) at relatively higher concentrations of CCA preservative (toxic limits: 0.24 – 0.48%m/m) and their heavy metal constituents (copper-salt: 5.0 – 10.0%m/m; chromium-salt: 0.076 – 0.24%m/m) than the faster growing mould isolate Paecilomyces variotii (CCA: 0.019 – 0.076%m/m; chromiumsalt: 0.076 – 0.24%m/m) and the white rot Basidiomycete of intermediate growth rate (CCA: 0.076 – 0.24%m/m; copper-salt: 0.076 – 0.24%m/m; chromium-salt: 0.0095 – 0.019%m/m) except for arsenic-salt (Phialophora fastigiata: 0.076 – 0.24%m/m; Paecilomyces variotii: 0.48 – 0.95%m/m; Basidiomycete: 0.24 – 0.48%m/m). The results showing varying efficacies (toxicity versus tolerance) in vitro of CCA and their metal constituents between these fungi can have implications to ground-contact wood protection capabilities of CCA