A comparison between superfine magnesium hydroxide powders and commercial dry powders on fire suppression effectiveness

The effectiveness of superfine magnesium hydroxide powders and commercial dry powder in fire suppression were compared in a laboratory-scale, immovable fire suppression apparatus. The investigation focused on their suppression effectiveness under various pressures. It likewise studied the relationship between the powders’ surface structures and their effectiveness on fire suppression. The microcosmic structure of the powders was observed by scanning electron microscope (SEM), while the Thermal Gravity Analysis (TGA) technique was used to analyze the thermal behavior of the superfine magnesium hydroxide powders. By analyzing the results, it could be concluded that the pressure, the particle size, and the microcosmic structure of the powders’ surface mainly decide the capability of the powders to extinguish the fire. Comparing this with commercial dry powders, superfine magnesium hydroxide powders extinguished the fire in less than 10 s.     

In-vehicle Measurement of Ultrafine Particles on Compressed Natural Gas, Conventional Diesel, and Oxidation-catalyst Diesel Heavy-duty Transit Buses

Many metropolitan transit authorities are considering upgrading transit bus fleets to decrease ambient criteria pollutant levels. Advancements in engine and fuel technology have lead to a generation of lower-emission buses in a variety of fuel types. Dynamometer tests show substantial reductions in particulate mass emissions for younger buses (<10 years) over older models, but particle number reduction has not been verified in the research. Recent studies suggest that particle number is a more important factor than particle mass in determining health effects. In-vehicle particle number concentration measurements on conventional diesel, oxidation-catalyst diesel and compressed natural gas transit buses are compared to estimate relative in-vehicle particulate exposures. Two primary consistencies are observed from the data: the CNG buses have average particle count concentrations near the average concentrations for the oxidation-catalyst diesel buses, and the conventional diesel buses have average particle count concentrations approximately three to four times greater than the CNG buses. Particle number concentrations are also noticeably affected by bus idling behavior and ventilation options, such as, window position and air conditioning.     

Carrousel氧化沟单个表曝机流态的模型试验和分析比较

对仅安装1个倒伞形表面曝气机(简称表曝机)的Carrousel氧化沟模型进行了水力学测定,通过颗粒动态分析仪(PDA)系统分析流出和流入表曝机一侧的液体流动速度、沉降速度,以及固体含量分布.结果表明,流出表曝机一侧,距表曝机较近的x轴位置流速较大;沉降速度沿y轴有个转折点,位于沟壁与挡板的中间;远离单个表曝机,固体含量逐渐增大.并将单个表曝机的测量结果与氧化沟内安装2个表曝机的流动试验进行比较,发现2个表曝机所产生的流场与单个表曝机产生的流场差别较大,且2个表曝机所产生的流场更稳定.      

New Genetic Approach to Detecting Individuals of Rare and Endangered Species

Abstract: Many rare and endangered species are difficult to locate, observe, and study. Consequently, many individuals, breeding pairs, and even populations of such species could remain undetected. Genetic markers can potentially be used to detect the existence of undiscovered individuals and populations, and we propose a method to do so that requires 3 conditions. First, sampling of the known population(s) of the target species must be comprehensive. Second, the species must display a reasonable level of philopatry and genetic structuring. Third, individuals must be able to be caught outside of breeding locations (e.g., at courtship or feeding areas, in flight), and the level of recapture must be reasonably high. We applied our method to the Chatham Island Taiko (Pterodroma magentae), one of the world's most endangered seabirds. We sequenced the Taiko mitochondrial cytochrome b gene and both copies of a fragment of the duplicated domain I of the control region. Twenty‐one haplotypes were revealed, including 4 (19%) not found in birds at known burrows. These results suggest there are more burrow groups yet to be located. The species is a pelagic gadfly petrel that inhabits land only in the breeding season during which it is nocturnal and nests in burrows. Taiko burrows are situated in dense forest in a remote area of Chatham Island, and are consequently difficult to locate and study. It is important that all Taiko burrows be discovered to enable monitoring and protection of the birds from exotic predators.     

Use of Chitosan as Coagulant to Treat Wastewater from Milk Processing Plant

Chitosan is a natural high molecular polymer made from crab, shrimp and lobster shells. When used as coagulant in water treatment, not like aluminum and synthetic polymers, chitosan has no harmful effect on human health, and the disposal of waste from seafood processing industry can also be solved. In this study the wastewater from the system of cleaning in place (CIP) containing high content of fat and protein was coagulated using chitosan, and the fat and the protein can be recycled. Chitosan is a natural material, the sludge cake from the coagulation after dehydrated could be used directly as feed supplement, therefore not only saving the spent on waste disposal but also recycling useful material. The result shows that the optimal result was reached under the condition of pH 7 with the coagulant dosage of 25 mg/l. The analysis of cost-effective shows that no extra cost to use chitosan as coagulant in the wastewater treatment, and it is an expanded application for chitosan.     

Foraging areas of king penguins from Macquarie Island in relation to a marine protected area

Twenty-three king penguins (Aptenodytes patagonicus) from Macquarie Island were tracked by satellite during the late incubation period in 1998–1999 to determine the overlap of the foraging zone of king penguins with an area to be declared a marine protected area (MPA) near the island. While all penguins left the colony in an easterly direction and traveled clockwise back to the island, three penguins foraged in the northern parts of the general foraging area and stayed north of 56°S. The remaining 20 penguins ventured south and most crossed 59°S before returning to the island. The total foraging area was estimated to be 156,000 km² with 36,500 km² being most important (where penguins spent >150 hr in total). North-foraging penguins reached on average 331 ± 24 km from the colony compared to 530 ± 76 km for the south-foraging penguins. The latter traveled an average total distance of 1313 ± 176 km, while the northern foragers averaged 963 ± 166 km. Not only did the penguins spend the majority of their foraging time within the boundaries of the proposed MPA, they also foraged chiefly within the boundaries of a highly protected zone. Thus, the MPA is likely to encompass the foraging zone of king penguins, at least during incubation.     

固体微粒气溶胶灭火剂的改性研究

固体微粒气溶胶灭火剂作为一种新型灭火剂具有优越的抑制火灾的性能,但其应用和推广的关键在于降低灭火气溶胶形成时的温度.本文利用TG方法分析了灭火剂的热分解过程,并通过测定固体微粒气溶胶灭火剂的释放速度、释放区温度分布及灭火性能,研究了固体微粒气溶胶灭火剂的降温消焰技术.同时对气溶胶的成分和固体粒子粒度分布进行了分析.     

Lead particle size and its association with firing conditions and range maintenance: implications for treatment

Six firing range soils were analyzed, representing different environments, firing conditions, and maintenance practices. The particle size distribution and lead (Pb) concentration in each soil fraction were determined for samples obtained from the backstop berms. The main factors that were found to influence Pb fragment size were the type of soil used to construct the berms and the type of weapon fired. The firing of high velocity weapons, i.e., rifles, onto highly angular soils induced significant fragmentation of the bullets and/or pulverization of the soil itself. This resulted in the accumulation of Pb in the finer soil fractions and the spread of Pb contamination beyond the vicinity of the backstop berm. Conversely, the use of clay as backstop and the use of low velocity pistols proved to be favorable for soil clean-up and range maintenance, since Pb was mainly present as large metallic fragments that can be recovered by a simple screening process. Other factors that played important roles in Pb particle size distribution were soil chemistry, firing distance, and maintenance practices, such as the use of water spray for dust suppression and deflectors prior to impact. Overall, coarse Pb particles provide much easier and more cost-effective maintenance, soil clean-up, and remediation via physical separation. Fine Pb particles release Pb more easily, pose an airborne Pb hazard, and require the application of stabilization/solidification treatment methods. Thus, to ensure sustainable firing range operations by means of cost-effective design, maintenance, and clean-up, especially when high velocity weapons are used, the above mentioned factors should be carefully considered.     

青海湖湖水性质、颗粒物沉积通量季节和年际变化——来自沉积物捕获器的研究

本文通过在青海湖南盆沉积中心试验性放置的Mark 8-13型时间序列沉积物捕获器所收集到的为期15个月的自然沉降颗粒物,分析了颗粒物沉积通量和物质组成,结合温盐传感器（CTD）所记录湖水参数数据的分析,讨论了青海湖上部10 m左右湖水中所发生沉积作用的季节与年际变化特征及其与环境参数的相互关系。结果表明,采集期间所沉降的总颗粒物具有显著季节和年际变化特征,其平均年沉降通量为112 g·m^-2·yr^-1,其组成主要是自生碳酸盐（高Mg方解石、文石）、生物壳体（介形虫、硅藻等）等内生作用形成的物质,以及少量的碎屑矿物。与实时监测的湖水参数比较表明,具有显著季节和年际变化的青海湖内生物质通量变化主要受控于夏季温度的变化。其沉积机制为：湖水温度的升高,有利于高Mg方解石和文石等自生矿物从碳酸盐过饱和的碱性湖水中结晶沉淀（盐度降低）,也有利于藻类和介形虫等微体生物大量繁殖,表现为温度偏高的2010年比2011年具有较低的湖水盐度和高得多的沉积通量。因此,青海湖自生碳酸盐沉淀通量可以用来反映湖水盐度和/或温度的变化,尽管这些内生作用形成的物质可能只约占到湖底沉积物的5%~20%。为更全面地了解青海湖现代沉积过程,有必要在更多点位、不同的深度进行长期放置捕获器和实时监测湖水参数变化。     

基于RBF和PSO的双喉道气动矢量喷管优化设计

本文探索了一种能多变量综合优化的方法,即对喷管进行参数化设计后,用均匀试验设计(UED)将试验样本均匀散布在设计区间内,求出各性能参数后,利用径向基神经网络(RBF)对试验样本进行拟合,再用粒子群算法(PSO)对训练好的神经网络进行寻优,找出了更好的双喉道气动矢量喷管设计参数组合。数值模拟结果显示,优化后的双喉道气动矢量喷管的矢量角有了明显提高。试验表明这种优化方法具有很好的优化能力,可以用来对喷管几何外形进行参数优化。 