Determination of Cadmium and Lead in Different Cigarette Brands in Jordan

Cadmium (Cd) and lead (Pb) concentrations in different cigarette brands sold and/or produced in Jordan were determined by graphite furnace atomic absorption spectrometry (GF-AAS). Average levels of Cd and Pb in different cigarette brands in Jordan were 2.64 and 2.67 g g^{– 1} (DW), respectively. The results obtained in this study estimate the average quantity of Cd inhaled from smoking one packet of 20 cigarettes to be in the range of 3.65–7.30 g. Results suggest that the quantity of Pb inhaled of smoking one packet of 20 cigarettes, is estimated to be 0.74–2.22 g. The concentrations of Cd and Pb in cigarettes were significantly different between cigarette brands tested. Our results were compared with other worldwide studies.     

流动注射—化学发光法测定大气二氧化硫

本文对大气二氧化硫的流动注射—化学发光法测定进行了研究.基于鲁米诺—碘—二氧化硫无机偶合化学发光反应,建立了测定大气二氧化硫的新方法.采用了流动注射气体扩散在线分离技术,使得经典的化学发光测定的选择性大大提高.对鲁米诺—碘这一化学发光体系有很强催化作用的金属离子及其它酸化后不挥发的物质均不影响本体系的测定.方法具有简单、快速、选择性好的特点.已用于大气环境监测分析,结果较满意.     

气相色谱法快速测定蔬菜中灭杀毙

用蒸馏水一次提取新鲜蔬菜样品，以SE－30和QF－1为固定液，Chromosorb W AW DMCS为固定相，2m填充柱分离，氢火焰检测器检测，进样10uL测定灭杀毙含量，以保留时间定性，外标法定量，分析时间小于150s，方法回收率95．4％，相对标准差3．6％，可用作上市蔬菜灭杀毙农药残留量的快速测定。     

Assessment of Calibration Parameters for an Aerial Gamma Spectrometry System using Monte-Carlo Technique

During a radiation emergency subsequent to a nuclear accident orweapon fallout, quick assessment of the ground contamination andthe resulting exposure is of prime importance in planning and execution of effective counter measures. For an online assessmentof ground contamination, it is essential to calibrate the detector system for several parameters viz. the source energy,source deployment matrix, the flight altitude and position abovethe contaminated surface. This article discusses the methodology to predict all the necessary parameters like photon fluence atvarious altitudes, the photo-peak counts in different energy windows, Air to Ground Correlation Factors (AGCF) and the doserate at any height due to air scattered gamma ray photons. Themethodology includes generation of theoretically simulated gammaspectra at a required detector position for a given source distribution on the ground using Monte-Carlo method provided by general purpose coupled neutron/photon transport code (MCNP CCC-200). Thus generated gamma spectra are analyzed to arrive at the required parameters mentioned above.     

气相色谱法测定水质苯系物

指出了气相色谱法测定水质苯系物存在的不足，提出用3％有机皂土－34＋2．5％邻苯二甲酸二壬酯混合涂渍的101坦体（60目－80目）不锈钢色谱柱分离苯系物，可在19min内分离水样中7种苯系物，对二甲苯与间二甲苯等难分离物质对可完全分离，改进后的样品前处理顶空装置操作简单、安全、可连续自动振荡，并且可以同时处理多个样品。     

Nontargeted identification of peptides and disinfection byproducts in water

A broad range of organic compounds are known to exist in drinking water sources and serve as precursors of disinfection byproducts(DBPs).Epidemiological findings of an association of increased risk of bladder cancer with the consumption of chlorinated water has resulted in health concerns about DBPs.Peptides are thought to be an important category of DBP precursors in water.However,little is known about the actual presence of peptides and their DBPs in drinking water because of their high sample complexity and low concentrations.To address this challenge and identify peptides and non-chlorinated/chlorinated peptide DBPs from large sets of organic compounds in water,we developed a novel high throughput analysis strategy,which integrated multiple solid phase extraction(SPE),high performance liquid chromatography(HPLC)separation,and non-target identification using precursor ion exclusion(PIE)high resolution mass spectrometry(MS).After MS analysis,structures of candidate compounds,particularly peptides,were obtained by searching against the Human Metabolome Database(HMDB).Using this strategy,we successfully detected 625 peptides(out of 17,205 putative compounds)and 617 peptides(out of 13,297)respectively in source and finished water samples.The source and finished water samples had 501 peptides and amino acids in common.The remaining 116 peptides and amino acids were unique to the finished water.From a subset of 30 putative compounds for which standards were available,25 were confirmed using HPLC-MS analysis.By analyzing the peptides identified in source and finished water,we successfully confirmed three disinfection reaction pathways that convert peptides into toxic DBPs.     

丁苯橡胶生产废水的生物降解特性

为研究丁苯橡胶生产废水的好氧生物降解特性,对某石化企业丁苯橡胶生产装置的生产废水进行好氧处理,并采用液液萃取-气相色谱/质谱、三维荧光光谱、紫外吸收光谱等手段对水质指标进行表征. 结果表明:经好氧生物降解后,丁苯橡胶废水中ρ(COD_Cr)和ρ(DOC)分别降至155和76 mg/L,COD_Cr和DOC去除率分别为76.07%和70.08%;废水中二苄胺、苯乙烯和十二烷基二甲基叔胺等9种主要特征有机物19 d内可被完全降解. 丁苯橡胶生产废水在λ_Ex/λ_Em(激发波长/发射波长)为225 nm/340 nm、215 nm/290 nm,275 nm/340 nm处有3个荧光峰,分别由二苄胺、十二烷基二甲基叔胺、苯乙烯、甲苯和苯甲醛等胺类、苯乙烯和芳香族化合物等有机物产生,好氧生物降解能去除废水中的绝大部分荧光物质,荧光峰强度的总去除率达到93.87%;废水中二苄胺、十二烷基二甲基叔胺、4-甲基环己酮、苯甲醛,苯乙烯、甲苯等有机物使丁苯橡胶生产废水分别在波长190~230、230~250、250~400 nm处有紫外吸收,好氧生物降解对UV₂₅₄的去除率达到52%. 研究显示,丁苯橡胶废水经单独好氧生物处理不能达到GB 31572—2015《合成树脂工业污染物排放标准》的要求,需结合其他方式进行联合处理.      

Gas dispersion risk analysis of safety gap effect on the innovating FLNG vessel with a cylindrical platform

While the effect of the safety gap on explosions is well known, little has been carried out to evaluate the effect of the safety gap on dispersion of gas releases, this paper evaluates the effect of safety gap on gas dispersion for a cylindrical Floating Liquefied Natural Gas (FLNG) vessel. The realistic ship-shaped and circular FLNG platforms are established and used for the detailed CFD based analysis; rather than the structural and hydrodynamics advantages of mobility, stability and cost efficiency etc., this study aims to investigate the safety of gas dispersion on the cylindrical FLNG and compare the safety gap effects on different configurations. A series of different safety gap configurations are evaluated for gas dispersion occurring in near field for the traditional FLNG while both near field and far field gas dispersion simulations are conducted on the cylindrical one. The overall results indicate that the safety gap is effective in reducing the gas cloud size in both FLNG configurations, however, when it comes to the gas dispersion in the far field against the leakage point, the safety gap increases the gas cloud size in the cylindrical FLNG vessel on the contrary.     

Influence of built-in obstacles on unconfined vapor cloud explosion

The obstacle structure in the vapor cloud has a significant influence on the gas explosion. Obstacles could not only lead to the acceleration of flame, but also they may occupy some space, thus affecting the amount of combustible gas. In this paper, a new two-step method was proposed to respectively study the effects of the obstacles amount and volume blockage ratio (VBR) on the gas explosion by using Computation Fluid Dynamic software AutoReaGas, and the obstacles in the vapor cloud were set to “Solid” instead of “Subgrid”. Based on the results and analysis, it is found that the peak overpressure and the maximum combustion rate rise with the increase of the number of obstacles for a single VBR, which indicated that the vapor cloud explosion of more obstacles was more dangerous for a single VBR. However, under a single number of obstacles, the peak overpressure and the maximum combustion rate increase firstly and then decrease as VBR increases and reach the highest at the VBR of 0.74, which indicated that the intensity of vapor cloud explosion reach a peak at a certain VBR in the middle instead of the largest. In addition, the existence and structure of obstacles have little effect on the size of explosion fireball when the size and concentration of combustible gas cloud are the same.     

A new technique helps to uncover unknown peptides and disinfection by-products in water

正Environmental water samples can be extremely complex,with potentially thousands of molecules that can derive from natural organic matter(NOM)and thousands that derive from anthropogenic contaminants.As complex as these samples are,drinking water can be even more complex.Due to disinfectants that are used to treat drinking water(e.g.,chlorine,chloramines,