Effects of upholstery materials on the burning behavior of real‐scale residential upholstered furniture mock‐ups

Fire spread and growth on real‐scale four cushion mock‐ups of residential upholstered furniture (RUF) were investigated with the goal of identifying whether changes in five classes of materials (barrier, flexible polyurethane foam, polyester fiber wrap, upholstery fabric, and sewing thread), referred to as factors, resulted in statistically significant changes in burning behavior. A fractional factorial experimental design plus practical considerations yielded a test matrix with 20 material combinations. Experiments were repeated a minimum of two times. Measurements included fire spread rates derived from video recordings and heat release rates (HRRs). A total of 13 experimental parameters (3 based on the videos and 10 on the HRR results), referred to as responses, characterized the measurements. Statistical analyses based on Main Effects Plots (main effects) and Block Plots (main effects and factor interactions) were used. The results showed that three of the factors resulted in statistically significant effects on varying numbers of the 13 responses. The Barrier and Fabric factors had the strongest main effects with roughly comparable magnitudes. Foam was statistically significant for fewer of the responses and its overall strength was weaker than for Barrier and Fabric. No statistically significant main effects were identified for Wrap or Thread. Multiple two‐term interactions between factors were identified as being statistically significant. The Barrier*Fabric interaction resulted in the highest number of and strongest statistically significant effects. The existence of two‐term interactions means that it will be necessary to consider their effects in approaches designed to predict the burning behavior of RUF.     

采用温控和碘吸收池技术的发射激光稳频技术

多普勒测风激光雷达通过分析系统回波信号的多普勒频移反演出风速，为提高风场探测精度，从稳频技术方面展开研究。在稳频过程中，分别采取措施消除激光频率的长期漂移和短期抖动。针对激光频率的长期漂移，设计并研制了种子激光器温控箱，通过水浴的控温方式大大减小了激光频率的长期漂移，将激光频率稳定在±50 MHz以内；针对激光频率的短期抖动，采用以碘分子吸收池为核心器件的稳频系统，通过半导体控温方式对碘分子吸收池精确控温，控温精度达0.03 ℃，提高了稳频精度，将激光频率进一步稳定在±8 MHz以内，满足±10 MHz以内的设计精度要求。通过搭建多普勒测风激光雷达系统，对发射激光稳频装置进行系统验证，连续4组风场观测结果表明:系统探测高度为17 km，绝大部分方差在4 m/s以下，满足测风激光雷达测量指标的要求。     

The influence of mining factors on seismic activity during longwall mining of a coal seam

In this article an attempt to determine the influence of mining factors on the seismic activity during the longwall mining of the upper layer of coal seam no. 405/2 in one of the Polish hard coal mines in the Upper Silesian Coal Basin was conducted. Two longwall panels were mined in analogous geological conditions and based on the same mining system and technology. However, there was significant difference with regards to the mining factors, which was reflected in the observed seismic activity. Some tools used in mining seismology were applied to illustrate the aforementioned influence of mining factors, e.g. the frequency-energy distribution, the frequency-magnitude distribution, the 2 D distribution of released seismic energy, the relationship between released seismic energy and the volume of mined coal, the Benioff strain release, and the Gutenberg-Richter(GR) b coefficient distribution(b is the proportion between high and low energy tremors). Concerning the Benioff strain release, a new solution, based on the slope of a fitted line in a moving time window, is proposed.     

煤泥燃烧过程中汞的迁移行为研究

采用在线汞测试方法，以山西省低热值煤电厂中掺烧的煤泥为研究对象，利用实验室小型流化床，研究煤泥中汞的热转化行为差异及共性特征、影响煤泥热转化过程中汞迁移的关键因素，以揭示煤泥热转化过程中汞污染物的迁移机理。结果表明，同一种煤泥，相同气氛，800、900、1 000 ℃下，燃烧温度对煤泥中的汞的释放比例没有变化；相同温度，汞的释放比例为氮气>空气>氧气。3种煤泥在相同燃烧条件下，汞的释放特征相似，元素汞的释放量和释放比例差异较大。释放量与煤泥中的汞含量正相关，释放比例与煤泥中汞的赋存形态有一定关系。     

Numerical simulation of the effect of multiple obstacles inside the tube on the spontaneous ignition of high-pressure hydrogen release

Self-ignition may occur during hydrogen storage and transportation if high-pressure hydrogen is suddenly released into the downstream pipelines, and the presence of obstacles inside the pipeline may affect the ignition mechanism of high-pressure hydrogen. In this work, the effects of multiple obstacles inside the tube on the shock wave propagation and self-ignition during high-pressure hydrogen release are investigated by numerical simulation. The RNG k-ε turbulence model, EDC combustion model, and 19-step detailed hydrogen combustion mechanism are employed. After verifying the reliability of the model with experimental data, the self-ignition process of high-pressure hydrogen release into tubes with obstacles with different locations, spacings, shapes, and blockage ratios is numerically investigated. The results show that obstacles with different locations, spacings, shapes and blockage ratios will generate reflected shock waves with different sizes and propagation trends. The closer the location of obstacles to the burst disk, the smaller the spacing, and the larger the blockage ratio will cause the greater the pressure of the reflected shock wave it produces. Compared with the tubes with rectangular-shaped, semi-circular-shaped and triangular-shaped obstacles, self-ignition is preferred to occur in tube with triangular-shaped obstacles.     

Iodine from brown algae in human nutrition,with an emphasis on bioaccessibility,bioavailability, chemistry,and effects of processing: A systematic review

Brown algae are becoming increasingly popular as a food source and dietary supplement in Europe and other Western countries. As they are highly rich in iodine, they represent a potential new dietary iodine source. Iodine deficiency has been re-emerging in Europe, and it is important to ensure adequate intake through one's diet. However, macroalgae, and especially brown algae, may contain very high amounts of iodine, and both iodine deficiency and excessive iodine may increase the risk of negative health effects. The iodine content of algae or foods containing algae is currently not regulated in the European Union. The aim of this paper is to review the literature to determine the chemical species of iodine in brown algae, the loss of iodine during processing, and the bioavailability and bioaccessibility of iodine. A systematic search of the literature was performed in April 2021, via the databases Web of Science and PubMed. The review includes studies of iodine in brown macroalgae in relation to bioavailability, bioaccessibility, processing and speciation. A meta-analysis was conducted in relation to the following topics: (i) the correlation between total iodine and iodide (I^–) content in brown algae; (ii) the correlation between the loss of iodine during processing and the I^– content; and (iii) the correlation between bioavailability and the I^– content. The bioavailability of iodine from brown algae was generally high, with in vivo bioavailability ranging from 31% to 90%. The in vitro bioavailability of iodine (2%–28%) was systematically lower than in vivo bioavailability (31%–90%), indicating an inadequate in vitro methodology. Processing may reduce the iodine content of brown algae, and a higher I^– content was positively correlated with increased iodine loss during processing. Although processing strategies may reduce the iodine content of brown algae significantly, the iodine content may still be high after processing. These findings may be used in food safety evaluations of brown algae as well as in the development of macroalgae-containing foods with iodine contents suitable for human consumption. Further research on processing techniques to reduce the iodine content in brown macroalgae are warranted.     

Improvement of a commercial calcium phosphate bone cement by means of drug delivery and increased injectability

Calcium phosphate cements (CPCs) have been increasingly used as synthetic bone substitutes for repair and regeneration of bone defects given their biocompatibility, resemblance to bone and malleability. Moreover, their use as local antibiotic delivery systems is of main interest against bone infections, avoiding the adverse effects of high dosages of conventional therapy. The main goals of this work were to improve the properties of a commercial CPC (Neocement®), turning it injectable, and to provide it with a new functionality as a drug delivery system able to ensure a sustained release of an antibiotic commonly used in orthopaedics (gentamicin sulphate, GS). For this, the influence of the liquid phase amount (%LP) and type of polymer contained in the formulation (chitosan, Chi, or hydroxypropyl methylcellulose, HPMC) on the basic properties of the material was evaluated. It was found that the formulation containing 42%LP + HPMC+1.87% wt GS was the best one. It showed suitable setting and mechanical properties, and injectability around 87% (much superior to the original Neocement®, with 31%). It ensured a sustained release of GS for at least 14 days, at antibacterial levels. The antibiotic released is highly effective against S. epidermidis, but also presents some antibacterial activity against S. aureus. The CPC revealed to be non-cytotoxic. Moreover, it demonstrated good flowability and connectivity with human cadaveric trabecular bone.     

Electrochemical Quantification of Neurotransmitters in Single Live Cell Vesicles Shows Exocytosis is Predominantly Partial

Exocytosis plays an essential role in the communication between cells in the nervous system. Understanding the regulation of neurotransmitter release during exocytosis and the amount of neurotransmitter content that is stored in vesicles is of importance, as it provides fundamental insights to understand how the brain works and how neurons elicit a certain behavior. In this minireview, we summarize recent progress in amperometric measurements for monitoring exocytosis in single cells and electrochemical cytometry measurements of vesicular neurotransmitter content in individual vesicles. Important steps have increased our understanding of the different mechanisms of exocytosis. Increasing evidence is firmly establishing that partial release is the primary mechanism of release in multiple cell types.     

Life time prediction of self-supporting flame-sprayed alumina-rich coatings

Main objective of the presented research is the life time prediction of self-supporting flame-sprayed Al₂O₃- and Al₂O₃ -ZrO₂ -TiO₂-materials under constant load. The characteristic life time and its scatter were derived from stable crack growth tests and Weibull-statistics including the four-point-bending and ball-on-three-balls method. The potential life time was estimated in order to assess room-temperature handling and long term storage of self-supporting flame-sprayed alumina components. In terms of flexural strength, energy release, and subcritical crack growth parameters, distinct differences between both materials were shown. In turn, the characteristic life times only barely deviated from each other. From that the conclusion was drawn that life time performance under constant load application is governed by the characteristic flame-spray microstructure. However, advantages in the flame-spray processing of Al₂O₃ - ZrO₂ -TiO₂ are still given, attributed to its lower melting temperature.