A critical assessment and thermodynamic calculation of the boron-carbon-titanium (B-C-Ti) ternary system

The B-C-Ti system has been critically assessed and calculated in the temperature region of 1400 °C up to the melting range employing the Thermocalc program system. The liquid phase is described using a substitutional model. The ternary solid solubility of boron in titanium carbide has been taken into account by using a two-sublattice model (Ti)₁(B,C,Va),. The calculated isotherms and isopleths are presented and compared with the experimental information. The B-C-Ti reaction scheme is presented including the Ti₃B₄ phase.     

Analysis‐preserving video microscopy compression via correlation and mathematical morphology

The large amount video data produced by multi‐channel, high‐resolution microscopy system drives the need for a new high‐performance domain‐specific video compression technique. We describe a novel compression method for video microscopy data. The method is based on Pearson's correlation and mathematical morphology. The method makes use of the point‐spread function (PSF) in the microscopy video acquisition phase. We compare our method to other lossless compression methods and to lossy JPEG, JPEG2000, and H.264 compression for various kinds of video microscopy data including fluorescence video and brightfield video. We find that for certain data sets, the new method compresses much better than lossless compression with no impact on analysis results. It achieved a best compressed size of 0.77% of the original size, 25× smaller than the best lossless technique (which yields 20% for the same video). The compressed size scales with the video's scientific data content. Further testing showed that existing lossy algorithms greatly impacted data analysis at similar compression sizes. Microsc. Res. Tech. 78:1055–1061, 2015. © 2015 Wiley Periodicals, Inc.     

l-Cystathionine Inhibits the Mitochondria-Mediated Macrophage Apoptosis Induced by Oxidized Low Density Lipoprotein

This study was designed to investigate the regulatory role of l-cystathionine in human macrophage apoptosis induced by oxidized low density lipoprotein (ox-LDL) and its possible mechanisms. THP-1 cells were induced with phorbol 12-myristate 13-acetate (PMA) and differentiated into macrophages. Macrophages were incubated with ox-LDL after pretreatment with l-cystathionine. Superoxide anion, apoptosis, mitochondrial membrane potential, and mitochondrial permeability transition pore (MPTP) opening were examined. Caspase-9 activities and expression of cleaved caspase-3 were measured. The results showed that compared with control group, ox-LDL treatment significantly promoted superoxide anion generation, release of cytochrome c (cytc) from mitochondrion into cytoplasm, caspase-9 activities, cleavage of caspase-3, and cell apoptosis, in addition to reduced mitochondrial membrane potential as well as increased MPTP opening. However, 0.3 and 1.0 mmol/L l-cystathionine significantly reduced superoxide anion generation, increased mitochondrial membrane potential, and markedly decreased MPTP opening in ox-LDL + l-cystathionine macrophages. Moreover, compared to ox-LDL treated-cells, release of cytc from mitochondrion into cytoplasm, caspase-9 activities, cleavage of caspase-3, and apoptosis levels in l-cystathionine pretreated cells were profoundly attenuated. Taken together, our results suggested that l-cystathionine could antagonize mitochondria-mediated human macrophage apoptosis induced by ox-LDL via inhibition of cytc release and caspase activation.     

On forecasting large and infrequent snow avalanches

Snow avalanches that threaten a highway or a residential area are often large avalanches that have a return period > 1 year. Danger assessment strongly relies on precipitation data since these avalanches are typically triggered by major snow storms. Given the extensive protection work that is in place in the European Alps, the avalanche control service (also called avalanche commission) responsible for danger assessment will usually monitor the avalanche situation throughout the winter, but only become active in case of a major snow fall. Related safety concepts describing the procedures and measures to be taken in a given danger situation are therefore often based on threshold values for new snow. By analysing the avalanche occurrence of a major avalanche path, we show that forecasting based on new snow amounts involves high uncertainty. Whereas the return period of an avalanche to, for example, the road was about 5 years, the return period for the corresponding new snow depth was substantially smaller, in our case slightly less than 2 years. Similar proportions were found for a number of other avalanche paths with different snow climate. The return period of the critical new snow depth was about 2–5 times smaller than the return period of the avalanche. This proportion is expected to increase with increasing return period. Hence, based on the return period of an avalanche path a first estimate for the critical new snow depth can be made. With a return period of the critical new snow depth of 1–2 years, avalanche prediction for individual avalanche path becomes very challenging since the false alarm ratio is expected to be high.     

Exhaust hood for steam turbines-single-flow arrangement

In the past, increased attention was given to the development of an optimal shape for the inlet part of LP turbine casings in SKODA POWER. A double-flow design is typically used for high power output turbines. An optimized shape for the internal diffuser has been found, which transforms the kinetic energy of steam into increased pressure, thus effectively increasing the thermodynamic efficiency of the stage. Some conclusions have been drawn from laboratory experiments, others derived directly from on-site measurements at power plants. The conclusions from the development of double-flow turbines form the basis for the design of the single-flow turbine arrangement. Single-flow design is typically used for lower output turbines. There are still some limitations in applying this arrangement. The designer needs to resolve the bearing position and how to ensure access to them. Reinforcing the ribs and supports are used, therefore, to ensure the rigidity of the entire casing. The optimization of the single-flow diffuser shape is therefore the subject of the study presented below.     

Oxidative Stress and NADPH Oxidase: Connecting Electromagnetic Fields,Cation Channels and Biological Effects

Electromagnetic fields (EMFs) disrupt the electrochemical balance of biological membranes, thereby causing abnormal cation movement and deterioration of the function of membrane voltage-gated ion channels. These can trigger an increase of oxidative stress (OS) and the impairment of all cellular functions, including DNA damage and subsequent carcinogenesis. In this review we focus on the main mechanisms of OS generation by EMF-sensitized NADPH oxidase (NOX), the involved OS biochemistry, and the associated key biological effects.     

On the calculation and representation of multicomponent systems

A data set was established to calculate the phase equilibria in the systems Si-Al-Zr-O-N and Si-Al-B-O-N. Complete phase diagrams of the quasibinary and quasiternary boundary systems, calculated by this data set, agree well with literature phase diagrams. To calculate equilibria of the multicomponent systems, Eriksson's program was modified to accept ionic species. The equilibria of some concentrations are plotted versus the temperature in phase amount diagrams.     

An alternative method for calculation of semi-gray radiation heat transfer in solar central cavity receivers

This paper describes a general method to calculate the semi-gray radiation heat transfer that occurs within an enclosure comprised of diffuse surfaces. The method is implemented in an existing solar power tower cavity receiver model in the System Advisor Model (SAM, NREL, 2011). The semi-gray radiation model is used to find an optimal distribution of emissivities for the thermal- and solar radiation wavelength bands for surfaces that comprise the solar central cavity receiver. The optimal distribution of emissivities maximizes the overall thermal efficiency of a cavity receiver. The model shows an effective way to reduce heat loss from the cavity is to minimize the temperatures of the passive surfaces through manipulation of their radiative surface properties.For the cavity receiver design considered, an optimal emissivity distribution for the active absorber surfaces of the cavity is a selective surface with high absorptivity in the solar wavelength band and low emissivity in the thermal wavelength band. Passive surfaces within the cavity should be highly reflective for radiation over the full spectrum. For absorber surfaces with solar absorptivity of 0.95, thermal emissivity of 0.1 and reflective passive surfaces with emissivities of 0.1, for the full spectrum, the thermal efficiency of the receiver can be increased by about 0.7% in comparison to gray surfaces having an emissivity of 0.95 for all wavelengths.     

Investigation on PEM water electrolysis cell design and components for a HyCon solar hydrogen generator

Hydrogen as a secondary energy carrier promises a large potential as a long term storage for fluctuating renewable energies. In this sense a highly efficient solar hydrogen generation is of great interest especially in southern countries having high solar irradiation. The patented Hydrogen Concentrator (HyCon) concept yields high efficiencies combining multi-junction solar cells with proton exchange (PEM) membrane water electrolysis. In this work, a special PEM electrolysis cell for the HyCon concept was developed and investigated. It is shown that the purpose-made PEM cell shows a high performance using a titanium hybrid fiber sinter function both as a porous transport layer and flow field. The electrolysis cell shows a high performance with 1.83 V at 1 A/cm² and 24 °C working under natural convection with a commercially available catalyst coated membrane. A theoretical examination predicts a total efficiency for the HyCon module from sunlight to hydrogen of approximately 19.5% according to the higher heating value.