Characterization of fulvic acids during olive mill waste composting (Elemental, Thermal and fluorescence analyses)

Elemental analysis, fluorescence spectroscopy and differential scanning calorimetry (DSC) were applied to the study of fulvic acids isolated from different stages during olive mill waste composting. The fulvic extracted acids are characterized by a high nitrogen content and O/C ratio values that may result from the high degree of humification and the synthesis of more condensed humic complexes. This was confirmed by fluorescence spectroscopy in the synchronous-scan mode by the decrease of shoulder intensities at intermediate wavelengths indicating the increase of polycondensation and conjugation of unsaturated structures and the greater uniformity of fluorophores. Fluorescence spectra in the emission, excitation and synchronous modes became simpler with compost maturation. This was confirmed by DSC results which proved the high degree of polycondensation of aromatic nuclei of fulvic acid molecules during olive mill waste composting.     

氟碳涂料实验室循环盐雾试验后防腐蚀行为研究

目的 研究氟碳重防腐涂层在循环盐雾试验后的防护性能.方法 开展氟碳涂层的实验室循环盐雾试验,通过电化学阻抗谱、附着力、光泽、色差测试等方法对氟碳涂层的各性能进行分析表征,并使用等效电路图对电化学阻抗谱数据进行拟合,评价涂层在盐雾试验后的腐蚀保护性能.结果 循环盐雾试验1440 h后,涂层无失光、变色、粉化等现象,模值由1.42×1011?·cm2下降至7.26×1010?·cm2,下降幅度较小.结论 经循环盐雾试验后的氟碳涂层仍具有优异的防护性能.     

Synchronous-scan fluorescence spectra of Chlorella vulgaris solution

The characterization of the Chlorella vulgaris solution was carried out using synchronous-scan spectroscopy. The range of concentration of algae and Fe(III) in aqueous solutions were 5 × 10⁸–8 × 10⁹ cells l⁻¹ and 10–60 μM, respectively. Effective characterization method used was synchronous-scan fluorescence spectroscopy. The wavelength difference (Δλ) of 90 nm was maintained between excitation and emission wavelengths; 90 nm was found to be the best Δλ for effective characterization of Chlorella vulgaris solution with or without quencher species (e.g., Fe(III), humic acid (HA)) for the first time. The peak was observed at about EX 236.6 nm/EM 326.6 nm for synchronous-scan fluorescence spectra. The fluorescence quenching of algae in system of algae–Fe(III)–HA was studied using synchronous-scan spectroscopy for the first time. Fe(III) was clearly the effective quencher. The relationship between I₀/I (quenching efficiency) and c (concentration of Fe(III) added) was a linear correlation for the algae solution with Fe(III). Also, Aldrich humic acid was found to be an effective quencher. pH effect on synchronous-scan fluorescence intensity of algal solution with Fe(III) and/or HA was evident.     

Investigation of fault position and sources of radon by measurement of 238U decay series radionuclide activity in soil samples

North Derbyshire is designated a Radon Affected Area by the National Radiological Protection Board of Great Britain since more than 1% of the housing stock is estimated to have radon levels in excess of the 200 Bq m-3 Action Level. Enhanced radon emissions associated with geological faults make knowledge of their position important in relation to any potential residential or industrial development. A general survey of radionuclides present in the soils of north Derbyshire and their relationship to the underlying geology highlighted the difficulty of identifying the position of geological faults in the field. Using gamma-ray spectroscopy of soil samples the activity of three 238U decay series radionuclides (226Ra, 214Pb and 214Bi), which were taken as evidence of the presence of 222Rn which occurs in the same decay series, was measured to indicate the position of a fault by enhanced activity. The results also provided some evidence of the source of radon emitted at the fault. A comparison of this methodology with the more conventional soil gas analysis method is made.     

用荧光光谱研究腐殖酸与金属离子Al^3＋的配合作用

用同步荧光法对两种来源不同的腐殖酸与金属离子Ａｌ＾３＋的配合作用进行了研究,采用非线性回归分析,用荧光强度变化数据,拟合出金属配合物（１：１）的条件稳定常数Ｋ,在配合滴定进行的同时,探讨了溶液在５００ｎｍ处的瑞利散射现象。     

Characterization of dissolved organic matter from saline soils by fluorescence spectroscopy

In this paper hydrophilic (HI) and hydrophobic (HO) fractions of dissolved organic matter (DOM) extracted from soils at different degrees of salinisation were characterised by means of fluorescence spectroscopy in the emission, excitation and synchronous-scan modes. Results provided evidence of the different chemical nature of DOM fractions and allowed to distinguish hydrophilic and hydrophobic fractions extracted from the same soil substrate. The strong decrease in fluorescence intensity observed with the increasing salinity of the soils can be utilised to obtain information on the salinity level of different soil substrates by comparison of spectral fluorescence intensities.     

荧光光谱法鉴别海面溢油源的研究进展

本文以大量的研究成果介绍了荧光光谱技术在鉴别海面溢油源中的应用和进展。根据普通荧光光谱、同步扫描光谱、可变角同步扫描光谱和总荧光光谱等不同荧光光谱信息特等，论述了荧光光谱的三维特性及维特性及其在溢油鉴别中的应用。同时，结合低温荧光法、磷光光谱法、导数荧光光谱法等辅助方法和技术，介绍了国内外荧光光谱法鉴别海面溢油的新进展和新成果。     

两次金汞齐-冷原子荧光光谱法测定大气中的痕量气态总汞

建立了两次金汞齐-冷原子荧光光谱法(CVAFS)测定大气中痕量气态总汞(TGM)的方法。研究表明:本方法的绝对检出限为2 pg;当以0.2~0.4 L·min-1 采样速度,采集12~48 h时,采样效率> 99%,精密度为9.63%;样品经2次循环加热分析,热解吸效率> 99%。这种分析方法还可以运用到其他环境样品痕量汞的测定。     

Clove as antioxidant additive in diesel–biodiesel fuel blends in diesel engines

Increased NOx emission from usage of biodiesel is a burning issue to be dealt with. Many techniques have been adopted to reduce NOx emissions from diesel engines. The present experimental study deals with the analysis of performance and emission characteristics of Cotton Seed oil biodiesel with the addition of natural antioxidant extract of clove. FTIR analysis characterized the antioxidant by the presence of hydroxyl groups denoted by the corresponding wave number. The oxidation stability of the test samples was determined in terms of induction period by means of Rancimat test. The induction periods of the test fuel samples B100, B20, B20+CL1000, and B20+CL2000 were found to be 2.20 h, 2.73 h, 10.19 h, and 11.12 h, respectively. Thus, the addition of Clove antioxidant increased the oxidation stability of the biodiesel. Results show that the addition of antioxidant to biodiesel blend has increased the Brake Thermal Efficiency to a maximum of 4.71% and decreased the Brake Specific Fuel Consumption to a maximum of 6.25% at full-load conditions compared to Cotton Seed biodiesel blend. The addition of Clove extract antioxidant at a concentration of 1000 ppm and 2000 ppm decreases the NOx emission by 23.03% and 26.7%, respectively, at full-load conditions. However, CO emissions increased by 1.12% and 4.49% with the addition of CL1000 and CL2000 to B20, respectively. Similarly, HC emissions increased by 4.19% and 7.35% by the addition of CL1000 and CL2000 to B20, respectively. The increases in smoke with the addition of CL1000 and CL2000 to B20 were 42.48% and 47.71%, respectively.