Compositional analysis of Tuscan glass samples: in search of raw material fingerprints

SEM-EDX quantitative analyses were performed on 91 samples of vessel glass originating from a number of sites throughout Tuscany. A comparison with Venetian glass data is made in order to evaluate differences in glassmaking materials. The compositions of the samples provide clues about the different raw materials used in relation to recipes that changed slightly during the period covering the late Middle Ages to early Renaissance. Two kinds of ash used as a fluxing agent were identified, one of which is of east Mediterranean origin while the other is likely to be Spanish. Two types of silica sources were also found. One of these was recognized as being quartziferous river pebbles, while the other is proposed to be local sand.     

Methodology for separation and elemental analysis of volcanic ash nanoparticles

A methodology for separation, characterization, and quantitative elemental analysis of volcanic ash nanoparticles is proposed. A combination of field-flow fractionation in a rotating coiled column and membrane filtration is used in the isolation and separation of nanoparticles. The size and morphology of nanoparticles were studied by static light scattering and scanning electron microscopy. The concentration of major- and trace elements in the bulk sample and the separated fractions was determined by inductively coupled plasma atomic emission spectrometry and mass spectrometry. It is shown that the total concentrations of most elements in the ash sample are comparable to their average concentrations in the Earth’s crust. On the other side, in the fraction 50–100 nm, the concentrations of Ni, Zn, Ag, Sn, Sb, Pt, Tl, Pb, and Bi are one or two orders of magnitude higher than their total concentrations, which probably indicates the preconcentration of corresponding elements from volcanic gases by nanoparticles. In the fraction represented by water-soluble forms of elements and nanoparticles smaller than 50 nm, Cu, Zn, Pb, and several other elements are found; the partition of elements between the solution and solid phase (nanoparticles) is assessed. The proposed methodology requires further development and application to the analysis of volcanic ash from various regions of the Globe.     

On strontium and barium anomalies in the sediments of Charkadio Cave (Tilos Island,Dodekanese, Greece)

The sediments of Charkadio Cave (Island of Tilos) have been object of chemical and mineralogical investigation. Sampling the speleothems of Charkadio Cave, it is possible to look back into the island’s younger geological history. Tilos is of non-volcanic origin but neighbored to several volcanoes of the Aegean (Kos, Nisyros, and Giali). We observed a certain coincidence of increased Ba and Sr values in such samples and volcanic activity. Some of the layers of these fine-grained sediments contain volcanic particles (ash grains and lapilli). Interestingly, these strata have the highest content of Ba and Sr, as determined by neutron activation analysis. Additionally to this discovery, Sr-rich barite crystals were found in some of these layers. Thus, Ba and Sr must either exist on the surface of tephra particles in volatile and water-soluble compounds and/or were released by weathering from Ba and Sr containing feldspars (originating from pumice) in the cave sediment environment. Since other cave sediments from Tilos, which were not exposed to volcanic products, contain very much lesser quantities of Ba and Sr, we conclude that mobile Ba and Sr compounds are contributed to the sediment by volcanic fallout.     

高钙高铁煤灰熔融及黏温特性研究

以金鸡滩煤为原料,沙子为添加剂,研究不同比例添加剂下高钙高铁煤灰熔融及黏温特性变化;通过XRD、高温热台显微镜与扫描电镜-能谱等分析方法研究矿物质转变对其灰熔融及黏温特性影响。结果表明,煤灰熔点随添加剂量的增加先降低后升高,辉石类低温共熔物生成是其降低的主要原因;原煤熔渣黏度波动与钙铝黄长石生成有关,而含铁矿物质析出导致其黏度迅速增加;添加沙子后,煤灰熔渣临界温度显著下降,熔渣由结晶渣向玻璃渣转变。原煤熔渣中Fe、Ca元素分布不均匀,添加沙子后均匀程度明显改善,与黏温曲线测试结果吻合。实验结果表明,沙子是改善高钙高铁煤黏温特性的一种有效添加剂。     

Speciation analysis of antimony in extracts of size-classified volcanic ash by HPLC–ICP-MS

Although there is concern about the presence of toxic elements and their species in environmental matrices, for example water, sediment, and soil, speciation analysis of volcanic ash has received little attention. Antimony, in particular, an emerging element of environmental concern, has been less studied than other potentially toxic trace elements. In this context, a study was undertaken to assess the presence of inorganic Sb species in ash emitted from the Copahue volcano (Argentina). Antimony species were extracted from size-classified volcanic ash (<36 microm, 35-45 microm, 45-150 microm, and 150-300 microm) by use of 1 mol L(-1) citrate buffer at pH 5. Antimony(III) and (V) in the extracts were separated and quantified by high-performance liquid chromatography combined on-line with inductively coupled plasma mass spectrometry (HPLC-ICP-MS). Antimony species concentrations (microg g(-1)) in the four fractions varied from 0.14 to 0.67 for Sb(III) and from 0.02 to 0.03 for Sb(V). The results reveal, for the first time, the occurrence of both inorganic Sb species in the extractable portion of volcanic ash. Sb(III) was always the predominant species.     

Major element analysis of selected rock and volcanic ash samples in the Unzen area,Japan, by X-ray fluorescence spectroscopy

Determination of major elements in natural solid samples by X-ray fluorescence spectroscopy (XRF) with a fusion disc technique is described. Data obtained by the present XRF analytical system were found to have satisfactorily high reliability. Five rock samples and a volcanic ash sample with varying ages ranging from the present to 180 000 years, derived by the current and past volcanic activities in the Unzen area, Nagasaki, Japan were analyzed for their major elements' compositions using the above mentioned system. The chemical composition of the magma under this area has changed very little at least over the last 180 000 years.     

Identification and characterization of individual airborne volcanic ash particles by Raman microspectroscopy

We present for the first time the Raman microspectroscopic identification and characterization of individual airborne volcanic ash (VA) particles. The particles were collected in April/May 2010 during research aircraft flights, which were performed by Deutsches Zentrum für Luft- und Raumfahrt in the airspace near the Eyjafjallajökull volcano eruption and over Europe (between Iceland and Southern Germany). In addition, aerosol particles were sampled by an Electrical Low Pressure Impactor in Munich, Germany. As references for the Raman analysis, we used the spectra of VA collected at the ground near the place of eruption, of mineral basaltic rock, and of different minerals from a database. We found significant differences in the spectra of VA and other aerosol particles (e.g., soot, nitrates, sulfates, and clay minerals), which allowed us to identify VA among other atmospheric particulate matter. Furthermore, while the airborne VA shows a characteristic Raman pattern (with broad band from ca. 200 to ca. 700 cm^?1 typical for SiO₂ glasses and additional bands of ferric minerals), the differences between the spectra of aged and fresh particles were observed, suggesting differences in their chemical composition and/or structure. We also analyzed similarities between Eyjafjallajökull VA particles collected at different sampling sites and compared the particles with a large variety of glassy and crystalline minerals. This was done by applying cluster analysis, in order to get information on the composition and structure of volcanic ash.

Use of Spanish Moss as an atmospheric monitor for trace elements

Samples of Spanish Moss (Tillandsia usneoides L.) were analyzed by neutron activation analysis (NAA) and inductively coupled argon plasma emission spectrometry (ICP) for trace elements as atmospheric environmental monitors. The plant material was collected at a single location in east Texas, then deployed along a 6×6 matrix gridwork in the extreme northeastern corner of the state. The study area includes several possible pollution sources including fossil fuel fired power plants. Two separate study periods were conducted, one during the summer months of 1989 and the other the following winter. Concentrations of about 35 elements were determined and contour plots for each element were pepared for each study period. Concentration ranges were found to be somewhat lower than those reported in other studies using epiphytic plants as environmental indicators. Initial correlations between elements and the possible relationships to pollution sources are discussed.     

Variation of the thorium to uranium ratio in rain: Thorium-230 chronology of the eruptions of Mt. St. Helens and El Chichón volcanoes

Principles of the thorium-230 dating method were applied to the study of thorium and uranium isotopes in a series of rain samples collected at Fayetteville (36°N, 94°W), Arkansas, since 1980. The results indicate that the rainwater contains volcanic ash materials with a wide variety of ages, which were blown up onto the upper stratosphere from the 18 May 1980 eruption of Mount St. Helens and the 28 March 1982 eruption of E1 Chichón. These volcanic materials seem to have stayed airborne for a number of years and profoundly affected the global atmospheric inventories of thorium and uranium isotopes.This investigation was supported by the National Science Foundation under Grant ATM 84-07618.     

Trace element partitioning in Texas lignite combustion

Trace element partitioning was studied at a pulverized-lignite fired power plant in Texas. Concentrations of 41 elements were determined by neutron activation analysis (NAA) for lignite fuel and combustion effluents collected during 10 consecutive days. Elements studied were grouped into three classes according to their enrichment factors and the relationship between their concentrations and particle size. In general, the concentration enhancement in fly ash and the difference in enhancement between elements placed in different classes are shown to be less significant in this study than for other partitioning studies on higher rank coals.     

Mixing of atmospheric <Superscript>210</Superscript>Pb and <Superscript>7</Superscript>Be and <Superscript>137</Superscript>Cs and <Superscript>90</Superscript>Sr fission products in four characteristic soil types

Depth distribution of atmospheric ²¹⁰Pb and ⁷Be and ⁹⁰Sr and ¹³⁷Cs fission products was measured in two types of aeolian soils (desert dust and volcanic ash), irrigated paddy soil and strongly acidic soil. The depth dependence of ²¹⁰Pb, ⁷Be and ¹³⁷Cs show that these radionuclides have been diffused as solid soil particles in surface soil layers. In aeolian soil layers, about 50% of ⁹⁰Sr were diffused in surface soil layer and the remaining 50% had penetrated to deeper layers. The half of the fission particles containing ⁹⁰Sr were shown to have decomposed over the past 35 years.     

Comparative Toxicity of Fly Ash: An In Vitro Study

Fly ash produced during coal combustion is one of the major sources of air and water pollution, but the data on the impact of micrometer-size fly ash particles on human cells is still incomplete. Fly ash samples were collected from several electric power stations in the United States (Rockdale, TX; Dolet Hill, Mansfield, LA; Rockport, IN; Muskogee, OK) and from a metallurgic plant located in the Russian Federation (Chelyabinsk Electro-Metallurgical Works OJSC). The particles were characterized using dynamic light scattering, atomic force, and hyperspectral microscopy. According to chemical composition, the fly ash studied was ferro-alumino-silicate mineral containing substantial quantities of Ca, Mg, and a negligible concentration of K, Na, Mn, and Sr. The toxicity of the fly ash microparticles was assessed in vitro using HeLa cells (human cervical cancer cells) and Jurkat cells (immortalized human T lymphocytes). Incubation of cells with different concentrations of fly ash resulted in a dose-dependent decrease in cell viability for all fly ash variants. The most prominent cytotoxic effect in HeLa cells was produced by the ash particles from Rockdale, while the least was produced by the fly ash from Chelyabinsk. In Jurkat cells, the lowest toxicity was observed for fly ash collected from Rockport, Dolet Hill and Muscogee plants. The fly ash from Rockdale and Chelyabinsk induced DNA damage in HeLa cells, as revealed by the single cell electrophoresis, and disrupted the normal nuclear morphology. The interaction of fly ash microparticles of different origins with cells was visualized using dark-field microscopy and hyperspectral imaging. The size of ash particles appeared to be an important determinant of their toxicity, and the smallest fly ash particles from Chelyabinsk turned out to be the most cytotoxic to Jukart cells and the most genotoxic to HeLa cells.     

Antimony in the environment as a global pollutant: a review on analytical methodologies for its determination in atmospheric aerosols

This review summarizes and discusses the research carried out on the determination of antimony and its predominant chemical species in atmospheric aerosols. Environmental matrices such as airborne particulate matter, fly ash and volcanic ash present a number of complex analytical challenges as very sensitive analytical techniques and highly selective separation methodologies for speciation studies. Given the diversity of instrumental approaches and methodologies employed for the determination of antimony and its species in environmental matrices, the objective of this review is to briefly discuss the most relevant findings reported in the last years for this remarkable element and to identify the future needs and trends. The survey includes 92 references and covers principally the literature published over the last decade.     

Influence of pre-curing time on the hydration of binder and the properties of concrete under steam curing condition

There is a pre-curing period before the freshly made concrete elements were exposed to steam curing in the steam curing process. In this paper, the influence of pre-curing time on the hydration of binder and the properties of concrete under steam curing condition was investigated. Three binders were used: the pure cement, the binder containing high content of GGBS, and the binder containing high content of fly ash. Three pre-curing times (1, 3, and 6 h) and one steam curing period at 60 °C (over 8 h) were adopted. Results show that pre-curing time has limited influence on the hydration degree of binder, and compressive strength and pore structure of paste. The influence of pre-curing time has limited influence on the compressive strength and chloride permeability of the pure cement concrete and the concrete containing high content of GGBS at whether early or late ages, indicating that the proper pre-curing time can be as short as 1 h for these two concretes. Increasing pre-curing time enhances the late-age compressive strength of the concrete containing high content of fly ash significantly, but it has limited influence on the late-age permeability.     

Systematic analysis of natural pozzolans from Greece suitable for repair mortars

Natural pozzolans were used as pozzolanic cement in concrete mixtures to increase the long-term strength, the concrete durability, and other material properties of Portland cement many centuries ago. The most common pozzolan is the volcanic ash, a siliceous or aluminosiliceous material, which is highly vitreous, coming from volcanic eruptions. In the Greek territory, 39 reactive volcanoes have been recorded both in insular and in terrestrial areas. The reactivity of pozzolans, in the case of lime-based mortars, is attributed to their content in amorphous silica which reacts with Ca(OH)₂ from lime, in environmental conditions, and forms C–S–H compounds responsible for the strength gain. Their use in building materials was diachronic. The significant properties of mortars containing pozzolans derive from the mechanism of its gradual strengthening attributed to the reaction of silicates with lime to form secondary cementitious phases which increase the durability and the dense structure of the mortars. In the present paper, two natural pozzolans from Greece are analyzed in order to record their morphological and analytical microstructure as well as their thermal and physical properties. The results revealed that the pozzolans tested, are materials of high quality and can be used for the production of compatible repair mortars. Also, valuable criteria could be instituted for the selection of reactive pozzolans which could be used for conservation purposes. Among others, crucial parameters for compatibility between old mortars and new ones are the surface features (color, texture, and roughness), the composition (type of binder, granulometry of aggregate), and the pore size distribution.     

Instrumental neutron activation analysis of coal and its combustion residues from a power plant

A growing demand of electrical energy derived from coal combustion led to a significant increase of coal ash as residues. Approximately 70 % of the fly ashes are recycled, while most of the bottom ashes have been land-filled in the ash pond in Korea. In this work, to evaluate the potential impacts of the residues from a coal power plant on the environment, its inorganic elemental components were determined by INAA and PGAA. Coal ash samples were collected from the biggest power plant complex in Korea. These samples were analyzed by using the NAA facilities in the HANARO research reactor of the Korea Atomic Energy Research Institute. A total of 31 elements were analyzed in the samples, and certified reference materials were used for the analytical quality control. The enrichment status of a given metal in fuel coal and ashes was investigated by its concentration ratio. In order to assess the impact of the coal combustion residues on ecosystem, their concentrations determined for each respective type of the samples were compared to both reference data and nearby beach sand samples.     

Saturated hydraulic conductivity of a volcanic ash soil affected by repulsive potential energy in a multivalent anionic system

Acid rain is supposed to influence soil structures, because soils have pH-dependent charges. The adverse effects of acid rain on soils must be assessed. Although repulsive potential energy among soil clay particles generates swelling and dispersion, thereby changing the soil’s hydraulic conductivity, the relationship between hydraulic conductivity and repulsive potential energy has not been evaluated. Moreover, research into repulsive potential energy in multivalent counterionic systems has been rare. In this paper, repulsive potential energies for a volcanic ash soil (allophanic Andisol), which is characterized by a number of pH-dependent charges, were evaluated in a multivalent counterionic system. Changes in saturated hydraulic conductivity (K) of volcanic ash soil during dilute acid leaching and their relationship with the repulsive potential energies were examined. When nitric acid at pH 3 or 4 was leached, K decreased rapidly. On the other hand, the decrease in K attenuated as the proportion of sulfate in the dilute acid increased. Electrophoretic mobilities were measured and the zeta potentials were estimated. From the zeta potentials and the calculation of repulsive potential energies between the clay particles in the NO₃–SO₄ system, we concluded that the decrease in K for an acid solution with a high proportion of nitrate was due to swelling and dispersion of the soil induced by electrostatic repulsive potential energy. Because sulfate formed complexes on the clay surface, the repulsive potential energy decreased as the proportion of sulfate in the dilute acid increased. Then, the flocculation of the soil was maintained, thereby inhibiting the decrease in K.     

The difference among the effects of high-temperature curing on the early hydration properties of different cementitious systems

The difference among the effects of high-temperature curing on the early hydration properties of the pure cement, the binder containing fly ash, the binder containing GGBS, and the binder containing steel slag was investigated by determining the compressive strength, non-evaporable water content, hydration heat, and Ca(OH)₂ content. Results show that the order of the influence degrees of high-temperature on the early hydration of different binders is the binder containing GGBS > the binder containing steel slag > the binder containing fly ash > the pure cement. In the case of short period of high-temperature curing (only 1 day), the strength growth rate of the concrete containing GGBS is the greatest. Though the influence of increasing high-temperature curing period on the hydration degree of the binder containing fly ash is not the most significant, the strength growth rate of the concrete containing fly ash is the most significant due to the excessive consumption of Ca(OH)₂ by reaction of fly ash. In the case of high-temperature curing, the Ca(OH)₂ content of the paste containing steel slag is much higher than those of the paste containing GGBS and the paste containing fly ash, so though high-temperature curing promotes the hydration of the binder containing steel slag significantly, its influence on the strength growth rate of the concrete containing steel slag is not so significant.     

A pilot study for the statistical treatment of nutritional parameters in the quality control of canned fishing goods.

This pilot study was derived as a consequence of European Directives 496/90 and 493/91 in which a regulation on the labeling of canned fishing goods was established. The study was intended primarily to assess whether different Spanish canned fishing goods might be differentiated by their basic nutritional composition (i.e., ash, chlorine as NaCl, fat, humidity, total proteins, and dry residue) and, second, to study each particular type of good. Accordingly, a univariate nonparametric statistical test and 2 multivariate chemometric techniques (factor and cluster analyses) were used. The pilot study revealed that (1) the basic nutritional variables did not allow a clear distinction among canned goods when different commodities were considered, but they seemed useful for obtaining information for only one type of good; and (2) the variables that gave the most useful information to visualize the appearance of groups in the data sets were humidity, dry residue, fat, and proteins, although their particular usefulness was found to be different when different species were considered.     

五彩湾煤灰的烧结特性及不同添加剂的影响规律

采用热机械分析仪、高温热台显微镜、XRD及FactSage软件相结合的方法,研究了五彩湾煤灰的烧结特性及不同添加剂的影响规律。结果表明,沙子(SiO_2含量约为80%)和煤矸石(SiO_2含量为54%,Al_2O_3含量为42%)能改变煤灰的烧结特性(烧结温度和烧结速率),但不同添加剂改变的程度不同。添加10%的沙子能使烧结温度提高70℃,而0-15%煤矸石不能使烧结温度升高。此外,烧结速率随添加剂增多而减小,烧结区间随添加剂增多而延长。进一步研究表明,添加剂能够改变煤灰初始液相温度、组成、含量、煤灰中硫酸盐的分解温度及初始液相温度从而改变煤灰的烧结特性。