In situ determination of long-term basaltic glass dissolution in the unsaturated zone

2002 ◽  
Vol 190 (1-4) ◽  
pp. 113-122 ◽  
Author(s):  
Steven J Gordon ◽  
Patrick V Brady
Keyword(s):  
Unsaturated Zone ◽  
Basaltic Glass ◽  
Glass Dissolution

scholarly journals Atmospheric CO2, CH4, and CO with CRDS technique at the Izaña Global GAW station: instrumental tests, developments and first measurement results

2017 ◽  
Author(s):  
Angel J. Gomez-Pelaez ◽  
Ramon Ramos ◽  
Emilio Cuevas ◽  
Vanessa Gomez-Trueba ◽  
Enrique Reyes
Keyword(s):  
Drift Rate ◽  
Inlet Pressure ◽  
Response Functions ◽  
Measurement Results ◽  
Ambient Measurements ◽  
Acceptance Tests ◽  
Term Maintenance

Abstract. At the end of 2015, a CO2/CH4/CO Cavity Ring-Down Spectrometer (CRDS) was installed at the Izaña Global Atmosphere Watch station (Tenerife, Spain) to improve the Izaña Greenhouse gases GAW measurement programme, and to guarantee the renewal of the instrumentation and the long-term maintenance of this programme. We present the results of the CRDS acceptance tests, the processing of raw data applied through novel numerical codes, and the response functions used. Also, the calibration results, the implemented water vapour correction, the target gas injection statistics, the ambient measurements performed from December 2015 to July 2017, and their comparison with other continuous in situ measurements are described. The agreement with other in situ continuous measurements is good most of the time for CO2 and CH4, but for CO is just outside the GAW 2-ppb objective. It seems the disagreement is not produced by significant drifts in the CRDS CO WMO tertiary standards. The main novelties are: 1) determination of a slight CO2 correction that takes into account changes in the inlet pressure/flow rate; 2) detailed justification of the use of virtual tanks to monitor the response function changes in time; 3) drift rate determination for the pressure and temperature sensors located inside the CRDS cavity; 4) novelties in the determination of the H2O correction for CO; and 5) determination and discussion of the origin of the CRDS-flow inlet pressure and H2O dependences.

scholarly journals On-farm orchards of fruit trees

2010 ◽  
Vol 46 (Special Issue) ◽  
pp. S65-S69
Author(s):  
F. Paprštein ◽  
J. Sedlák ◽  
V. Holubec
Keyword(s):  
National Park ◽  
Fruit Trees ◽  
On Farm Conservation ◽  
Nursery Stock ◽  
Planting Materials ◽  
On Farm ◽  
The Given

Four on-farm plantations (KRNAP Vrchlabí, the Orchard of Reconciliation in Neratov, Podyjí National Park, and Šumava National Park) were successfully established in a traditional form, with large orchard trees on seedling rootstocks. Certain accessions (cultivars) for on-farm conservation in the given locality were selected, according to the incidence and presentation of genotypes in these particular areas. This information was obtained by localization of fruit trees <I>in situ </I>and the determination of certain cultivars. Nursery stock production for onfarm plantations is described. Because of the longevity of the plantation, seedling rootstocks were used for the production of planting materials for the on-farm plantations. Techniques of on-farm plantation establishment and orchard management are stated within the paper. Four established on-farm plantations have ensured the long-term preservation of landraces in their original areas.

Alteration of Basaltic Glass in Iceland as a Natural Analogue for Nuclear Waste Glasses: Geochemical Modelling with DISSOL

1988 ◽  
Vol 127 ◽  
Author(s):  
J. L. Crovisier ◽  
T. Advocat ◽  
J. C. Petit ◽  
B. Fritz
Keyword(s):  
Computer Code ◽  
Solution Chemistry ◽  
Iron Hydroxides ◽  
Basaltic Glass ◽  
Secondary Products ◽  
Glass Dissolution ◽  
Mineral Phases ◽  
Kinetic Effects ◽  
Good Agreement

ABSTRACTThe long term geochemical consequences of basaltic glass dissolution in fresh water at 0°C have been calculated with the computer code DISSOL. The clay minerals were represented by an ideal solid solution model (CISSFIT) able to describe variations in chemical composition of a clay phase in response to variations of the solution chemistry. The predicted mineral phases were iron hydroxides followed by kaolinite, TOT clays, chabazite and cli-noptilolite. These results are in reasonably good agreement with experimental results and observations of altered subglacial hyaloclastites from Iceland. The formation of secondary products are mainly controlled by thermodynamic constraints. Kinetic effects, such as diffusion in the near glass surface are not important.

Heterogeneity Influence of Organic Matter on the Ozonation Chemiluminescence for Soils and Sediments

2012 ◽  
Vol 468-471 ◽  
pp. 1850-1855 ◽  
Author(s):  
Meng De Liu ◽  
Ping Ping Fan ◽  
Liu Yan ◽  
Li Bin Du ◽  
Guang Li Hou ◽  
...  
Keyword(s):  
Organic Matter ◽  
Rapid Determination ◽  
Marine Ecosystems ◽  
Soils And Sediments ◽  
Luminescence Time ◽  
Luminescence Characteristics ◽  
Soluble Fractions

Organic matter in soils and sediments is the key object of biogeochemistry in both terrestrial and marine ecosystems. Whether organic matter is the source or sink of carbon and nutrients can be predicted by its compositions and need continuous, long-term observations of organic matter compositions; therefore, in situ technologies are being investigated to meet the continuous, long-term observations. This study tried to explore a rapid determination of organic matter compositions by ozone chemiluminescence. After the soils or sediments were oxidized by ozone, their chemiluminescence characteristics such as luminescence maximum and time differed significantly. We hypothesized that the luminescence characteristics is controlled by the organic matter compositions. The soils and sediments were separated into extractives, acid soluble fractions (AS), and acid insoluble fractions (AIF), and then the original samples and their compositions were oxidized by ozone. Different organic matter compositions play a different role in the luminescence characteristics: extractives inhibited the luminescence maximum and luminescence time, AS increased the luminescence time and AIF increased the luminescence maximum. Results also showed that AIF can explain most variation of luminescence characteristics, suggesting that the luminescence characteristics are mainly controlled by the concentrations of AIF. Our study suggested that ozonaiton chemiluminescence have a strong potential to rapidly determine the chemistry of soils and sediments.

scholarly journals Efficient Oxidase Biosensors Based on Bioelectrocatalytic Surfaces of Electrodeposited Ferrocenyl Polycyclosiloxanes—Pt Nanoparticles

Chemosensors ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 81
Author(s):  
Alvaro Boluda ◽  
Carmen Casado ◽  
Beatriz Alonso ◽  
M. García Armada
Keyword(s):  
Xanthine Oxidase ◽  
Metallic Nanoparticles ◽  
Pt Nanoparticles ◽  
Covalent Immobilization ◽  
New Device ◽  
Long Term Stability ◽  
Fish Meat

The in-situ synthesis of catalytic surfaces with metallic nanoparticles must overcome the issues related to particle aggregation and polydispersity in the particle size. This work achieves it by using two electrodeposited ferrocenyl polycyclosiloxane polymers (MFPP and FPP) as templates for electro-synthesize Pt nanoparticles (PtNPS). In addition, this new electrode surface combines two efficient electrocatalysts: Ferrocene and Pt nanoparticles, with synergistic biocatalytic properties that constitute an electrocatalytic framework for the covalent immobilization of xanthine oxidase. In this work, we present the results of the kinetic, electrochemical and analytical studies of the prepared electrodes. These results showed that the PtNPs/FPP system is the best bioelectrocatalytic surface and improves other more complex xanthine oxidase devices based on the hydrogen peroxide oxidation, allowing the use of lower measuring potential with good sensitivity, wider linear ranges and low detection limits. In addition, this electrode provides the novelty of allowing the measurement of xanthine through the enzymatic consumption of oxygen at potential −0.1 V with a sensitivity of 1.10 A M−1 cm−2, linear ranges of 0.01–0.1 and 0.1–1.4 mM, low detection limit (48 nM) and long-term stability. The new device has been successfully applied to the determination of xanthine in fish meat.

A New Insight into the Nature of the Leached Layers Formed on Basaltic Glasses in Relation to the Choice of Constraints for Long Term Modelling

1988 ◽  
Vol 127 ◽  
Author(s):  
J. L. Crovisier ◽  
H. Atassi ◽  
V. Daux ◽  
J. Honnorez ◽  
J. C. Petit ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Basaltic Glass ◽  
Chemical Gradient ◽  
Glass Dissolution ◽  
Clayey Material ◽  
Congruent Dissolution ◽  
Ph Increase ◽  
Significant Chemical ◽  
Insight Into

ABSTRACTExperimental basaltic glass dissolution in fresh water is compared with analyses made on subglacial hyaloclastites from Iceland. The dissolution is initially selective and remains selective if the solution is renewed, whereas it becomes apparently congruent in non-renewed conditions. The congruent dissolution is ascribed to a pH increase (up to 7.0–7.5) which is hampered in the former conditions. The palagonite hydrated layer on the Icelandic basaltic glasses is made up of amorphous to crystallized clay-like materials. The chemical composition of palagonite is close to that of the intergranular clayey material, thus, it is inferred that in most cases no significant chemical gradient exists in the solution between the reaction zone, namely the glass/palagonite interface, and the intergranular solution. We conclude that the dissolution of basaltic glass under subglacial conditions is controlled by thermodynamics and that kinetic constraints, such as the diffusion of species through the altered layers, do not play a major role.

Rapid determination of the original boron isotopic composition from altered basaltic glass by in situ secondary ion mass spectrometry

2020 ◽  
Vol 35 (2) ◽  
pp. 238-245 ◽  
Author(s):  
Miaohong He ◽  
Xiaoping Xia ◽  
Xiaolong Huang ◽  
Jinlong Ma ◽  
Jieqiong Zou ◽  
...  
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Profile Analysis ◽  
Rapid Determination ◽  
Basaltic Glass ◽  
The Core ◽  
Secondary Ion ◽  
Isotopic Profile ◽  
Boron Isotopic Composition

Rapid determination of the original boron composition from altered basaltic glass by SIMS boron isotopic profile analysis from the core to rim.

Preparation And elemental analysis of ancient fibers

1987 ◽  
Vol 45 ◽  
pp. 410-411
Author(s):  
Allen Angel ◽  
Kathryn A. Jakes
Keyword(s):  
Cross Sections ◽  
Physical Structure ◽  
Energy Dispersive ◽  
Archaeological Sites ◽  
X Ray ◽  
Long Term Storage ◽  
Backscattered Electron ◽  
Electron Imaging

Fabrics recovered from archaeological sites often are so badly degraded that fiber identification based on physical morphology is difficult. Although diagenetic changes may be viewed as destructive to factors necessary for the discernment of fiber information, changes occurring during any stage of a fiber's lifetime leave a record within the fiber's chemical and physical structure. These alterations may offer valuable clues to understanding the conditions of the fiber's growth, fiber preparation and fabric processing technology and conditions of burial or long term storage (1).Energy dispersive spectrometry has been reported to be suitable for determination of mordant treatment on historic fibers (2,3) and has been used to characterize metal wrapping of combination yarns (4,5). In this study, a technique is developed which provides fractured cross sections of fibers for x-ray analysis and elemental mapping. In addition, backscattered electron imaging (BSI) and energy dispersive x-ray microanalysis (EDS) are utilized to correlate elements to their distribution in fibers.

Sign in / Sign up

Export Citation Format

Share Document