七氟丙烷气体清洁灭火剂的灭火原理

基于哈龙（Halon）灭火剂的消防产品是一种最为有效的气体消防系统。根据《蒙特利尔议定书》的建议，一些新的清洁消防灭火剂将用来取代哈龙减火剂。其中一种候选者就是七氟丙烷（Heptafluoropropane）灭火剂以及基于七氟丙烷的全覆盖灭火系统正开始应用于电脑机房、电信交换投施等领域。然而，大泉仍未封七氟丙烷灭火剂的灭火原理有一个全面了解。该类型系统的操作是有其缺点的，比如，使用遇程会产生氟化氩（hydrogen fluorideo本文将回顾哈龙灭火剂的灭火原理及使用中的一些相关问题，然後讨论七氟丙烷的化学分解遇程、灭火原理以及在使用遇程中减少氟化氢产生的添加剂妁工作原理。本文亦将简要介绍将水雾冷却系统（waterspray coolingsystem，WSCS）与七氟丙烷灭火剂结合以减少氟化氢产生的设想，同时会论及如何定义更好的添加剂的标准。     

2002 summer fires in Lithuania: impact on the Vilnius city air quality and the inhabitants health

The episodes with highly elevated concentrations of particulate matter (PM10), NOx, and CO were detected in the city of Vilnius between August and September 2002 and possible reasons were analysed. This increase was attributed to emissions from fires in the vicinity of the city of Vilnius when data on fire location and start, wind direction and concentrations of pollutants were analysed. The correlation coefficient between PM10 and CO, NO, NO2, NOx increased during the fire period in comparison with the same correlation after the fire period. During the fire episodes, there was an increase in concentration of ozone precursors, and meteorological conditions were favourable for photochemical reactions. Therefore, the hourly values for ozone exceeded the values common for Vilnius. Generally, during the episodes, the maximum of NO2 concentrations was 2 times higher than the limit value for NO2 laid down in the Council Directives 1999/30/EC [Council Directive 1999/30/EC of 22 April 1999 relating to limit values for sulphur dioxide, nitrogen dioxide and oxides of nitrogen, particulate matter and lead in ambient air. Official Journal L 163, 29/06/1999: 0041-0060], and that of PM10 was even 5.5 times higher than the limit value for PM10. Human health effects study in Vilnius indicated that the incidents of documented respiratory diseases and exacerbation of the bronchial asthma during the fire period were up to 20 times higher in comparison to periods with no fires.     

Speciation of iodine in solid environmental samples by iodine K-edge XANES: application to soils and ferromanganese oxides

A method was developed for speciation of iodine in solid materials using X-ray absorption near-edge structure (XANES). This method was used to identify the iodine species (mainly inorganic iodine) in environmental samples. It was shown that the XANES spectra of iodide and iodate sorbed within solid materials can be simulated by the linear combination of the spectra of iodide and iodate ions in water. The distribution coefficient (Kd) between soil and water was obtained independently for iodide and iodate, based on iodine speciation both in the solid phase, by XANES, and in the aqueous phase, by HPLC-ICP-MS. It was found that the Kd of iodate is larger than that of iodide by a factor of more than six, showing the more soluble nature of iodide. It was suggested that iodate can form in soil even when iodide is injected into the soil-water system under conditions within the iodide-stable field of the Eh-pH diagram of iodine. This is caused by the much higher affinity of iodate for solid surfaces than iodide. In soil samples under various water saturation conditions, or various Eh conditions, the iodide fraction in water increases with decreasing Eh, which results in an increase in the dissolved total iodine fraction in soil water. The speciation method using XANES was also applied to iodine in a natural soil sample and marine ferromanganese oxides. It is suggested that iodine K-edge XANES is a promising tool for determining the iodide/iodate ratio in natural solid samples, which contributes to better understanding of the behavior of iodine at the Earth's surface.     

An application of the GLUE methodology for estimating the parameters of the INCA-N model

The conceptual and parameter uncertainty of the semi-distributed INCA-N (Integrated Nutrients in Catchments-Nitrogen) model was studied using the GLUE (Generalized Likelihood Uncertainty Estimation) methodology combined with quantitative experimental knowledge, the concept known as 'soft data'. Cumulative inorganic N leaching, annual plant N uptake and annual mineralization proved to be useful soft data to constrain the parameter space. The INCA-N model was able to simulate the seasonal and inter-annual variations in the stream-water nitrate concentrations, although the lowest concentrations during the growing season were not reproduced. This suggested that there were some retention processes or losses either in peatland/wetland areas or in the river which were not included in the INCA-N model. The results of the study suggested that soft data was a way to reduce parameter equifinality, and that the calibration and testing of distributed hydrological and nutrient leaching models should be based both on runoff and/or nutrient concentration data and the qualitative knowledge of experimentalist.     

Formation of bromo-substituted triclosan during chlorination by chlorine in the presence of trace levels of bromide

The side reactions of triclosan (2,4,4'-trichloro-2'-hydroxydiphenyl ether, TC) and chlorine in the presence of sodium chloride were investigated. In the absence of sodium chloride, three chloro-derivatives of TC, 2',3,4,4'-tetrachloro-2-hydroxydiphenyl ether (3-Cl-TC), 2',4,4',5-tetrachloro-2-hydroxydiphenyl ether (5-Cl-TC), and 2',3,4,4',5-pentachloro-2-hydroxydiphenyl ether (3,5-Cl(2)-TC) were formed, whereas in the presence of sodium chloride, 3-bromo-2',4,4'-trichloro-2-hydroxydiphenyl ether (3-Br-TC), 5-bromo-2',4,4'-trichloro-2-hydroxydiphenyl ether (5-Br-TC), (3 or 5)-bromo-2',4,4',(5 or 3)-chloro-2-hydroxydiphenyl ether ((3,5)-(BrCl)-TC), and 3,5-dibromo-2',4,4'-trichloro-2-hydroxydiphenyl ether (3,5-Br(2)-TC) were additionally formed. Radiochemical neutron activation analysis indicated that 1g of commercially available sodium chloride contained 73 microg of bromide and the bromide ion was determined to be the source of the side reactions. The rate of decrease of TC due to reaction with chlorine was greatly accelerated by the presence of bromide ion in the system: the rate with only 1 x 10(-5) M bromide ion was three times the rate in the absence of bromide.     

Sources and temporal dynamics of arsenic in a New Jersey watershed, USA

We examined potential sources and the temporal dynamics of arsenic (As) in the slightly alkaline waters of the Wallkill River, northwestern New Jersey, where violations of water-quality standards have occurred. The study design included synoptic sampling of stream water and bed sediments in tributaries and the mainstem, hyporheic-zone/ground water on the mainstem, and seasonal and diurnal sampling of water at selected mainstem sites. The river valley is bordered by gneiss and granite highlands and shale lowlands and underlain by glacial deposits over faulted dolomites and the Franklin Marble. Ore bodies in the Marble, which have been mined for rare Zn ore minerals, also contain As minerals. Tributaries, which drain predominantly forested and agricultural land, contributed relatively little As to the river. The highest concentrations of As (up to 34 mug/L) emanated from the outlet of man-made Lake Mohawk at the river's headwaters; these inputs varied substantially with season--high during warm months, low during cold months, apparently because of biological activity in the lake. Dissolved As concentrations were lower (3.3 microg/L) in river water than those in ground water discharging into the riverbed (22 microg/L) near the now-closed Franklin Mine. High total As concentrations (100-190 mg/kg) on the <0.63 microm fraction of bed sediments near the mine apparently result from sorption of the As in the ground-water discharge as well as from the As minerals in the streambed. As concentrations in river water were diluted during high stream flow in fall, winter and spring, and concentrated during low flow in summer. In unfiltered samples from a wetlands site, diurnal cycles in trace-element concentrations occurred; As concentrations appeared to peak during late afternoon as pH increased, but Fe, Mn, and Zn concentrations peaked shortly after midnight. The temporal variability of As and its presence at elevated concentrations in ground water and sediments as well as streamwater demonstrate the importance of (1) sampling a variety of media and (2) determining the time scales of As variability to fully characterize its passage through a river system.     

Evaluation of Process Capability in Gas Carburizing Process to Achieve Quality through Limit Design Concept

NUMEROUS INDUSTRIAL APPLICATIONS requirea hard wear-resistant surface called the case,and arelatively soft,tough inside called the core.There arefive principal methods of case hardening:?Carburizing?Nitriding?Cyaniding or carbonitriding?Flame hardening?Induction hardeningThe first three methods change the chemicalcomposition,carburizing by the addition of carbon,nitriding by the addition of nitrogen and cyaniding bythe addition of both carbon and nitrogen.The last twomethods do n…     

Analysis on Phase Transformation (ATP) Using Computational Thermal Principles (CTP)

COMPUTER ANALYSIS is a method of computerapplication that is expected by heat treaters to yieldbetter results.Quenching is an integral part of industrialheat treatment processes for steels and provides ameans by which the mechanical properties of steel canbe controlled.During quenching,the steel is typicallycooled from above the austenizing temperature anddepending upon the temperature field developed withinthe material,different types of phase transformationsoccur which result in variet…     

Microstructure Transformation in the Welding Heat Affected Zone of 800MPa Grade Ultra Fine Structured Steel

The transformation behavior and microstructure development in the heat affected zone (HAZ) of 800MPa grade ultra fine structured steel was investigated. It was found that the HAZ has intermediate temperature transformation characteristics in a wide range of cooling rates, with the bainite sheaves consisting of bainite ferrite plates without carbide precipitation and retained austenite in the .fast cooling regime. At relatively high cooling rates, which corresponded to low heat inputs, the hardness o.f the simulated HAZ was above that of the base metal. When the cooling rate was below 9℃/s, the welding HAZ would have an obvious softening. The analysis of transformation rates in continuous cooling processes was completed by numerical differential method. The result indicated that the microstructure transformation rate o.f the HAZ in 800MPa grade ultra fine structured steel changed sharply to slow speeds when the cooling time t8/5 is longer than 7s.     

APPLICATION OF THE UNIFIED STATISTICAL MATERIAL DATABASE FOR DESIGN AND LIFE／RISK ASSESSMENT OF HIGH TEMPERATURE COMPONENTS

Statistical manipulation of material data was conducted for probabilistic life assessment or risk-based design and maintenance for high temperature components of power plants. To obtain the statistical distribution of material properties, dominant parameters affecting material properties are introduced into normalization of statistical variables. Those parameters are hardness, chemical composition, characteristic microstructural features and so on. Creep and fatigue properties are expressed by normalized parameters and the unified statistical distributions are obtained. These probability distribution functions show good coincidence statistically with the field database of steam turbine components. It was concluded that the unified statistical baseline approach is useful for the risk management of components in power plants.