Journal articles: 'The DGT technique'

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Dufka, Michaela, and Bohumil Dočekal. "Characterization of Urban Particulate Matter by Diffusive Gradients in Thin Film Technique." Journal of Analytical Methods in Chemistry 2018 (2018): 1–8. http://dx.doi.org/10.1155/2018/9698710.

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A diffusive gradient in thin films (DGT) technique was employed in characterization of the particulate matter related to the urban area suffering from heavy traffic. Kinetics of mobilization metals fluxes from the metal-contaminated particulate matter was investigated. To monitor responses of the particulate matter sample, DGT probes of various thickness of diffusion layer were deployed in aqueous model suspensions of the particulate matter for different time periods. Particulate matter samples and exposed DGT resin gels were decomposed in a mixture of nitric and hydrochloric acid in a microwave pressurized PTFE-lined system. Total content of some traffic-related elements (Cd, Co, Cu, Mo, Ni, Pb, Pd, Pt, Rh, Sb, and V) was determined by inductively coupled plasma mass spectrometry. DGT measurements revealed that two metals pools associated with particles could be recognized, which can be characterized as high soluble fraction and almost insoluble fraction. DGT-measured metal fluxes from the labile pool showed significant difference in mobilization and resupply fluxes of individual selected elements, which might reflect the origin of selected metals and their speciation in particulate matter. The DGT technique can be applied as a useful tool for characterization of metals mobilization from the particulate matter.

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Thomas, P. "Metals pollution tracing in the sewerage network using the diffusive gradients in thin films technique." Water Science and Technology 60, no. 1 (July 1, 2009): 65–70. http://dx.doi.org/10.2166/wst.2009.287.

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Diffusive Gradients in Thin-films (DGT) is a quantitative, passive monitoring technique that can be used to measure concentrations of trace species in situ in solutions. Its potential for tracing metals pollution in the sewer system has been investigated by placing the DGT devices into sewage pumping stations and into manholes, to measure the concentration of certain metals in the catchment of a sewage treatment works with a known metals problem. In addition the methodology and procedure of using the DGT technique in sewers was investigated. Parameters such as temperature and pH were measured to ensure they were within the limits required by the DGT devices, and the optimum deployment time was examined. It was found that although the results given by the DGT technique could not be considered to be fully quantitative, they could be used to identify locations that were showing an excess concentration of metals, and hence trace pollution back to its source. The DGT technique is ‘user friendly’ and requires no complicated equipment for deployment or collection, and minimal training for use. It is thought that this is the first time that the DGT technique has been used in situ in sewers for metals pollution tracing.

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Cusnir, Ruslan, Philipp Steinmann, François Bochud, and Pascal Froidevaux. "A DGT Technique for Plutonium Bioavailability Measurements." Environmental Science & Technology 48, no. 18 (August 27, 2014): 10829–34. http://dx.doi.org/10.1021/es501149v.

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Degryse, Fien, Erik Smolders, Hao Zhang, and William Davison. "Predicting availability of mineral elements to plants with the DGT technique: a review of experimental data and interpretation by modelling." Environmental Chemistry 6, no. 3 (2009): 198. http://dx.doi.org/10.1071/en09010.

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Environmental context. Total concentrations of mineral elements in soil bear little relation to their availability for plants. The DGT (diffusive gradients in thin-films) technique has been found to be a good predictor of trace metal uptake and P deficiency, though not consistently in all studies for all elements. This review examines the fundamental basis for the relation between DGT fluxes and plant uptake and assesses under which conditions this relation may break down. Abstract. In the DGT technique, elements are accumulated on a binding gel after their diffusive transport through a hydrogel. In this paper, we explore in more detail why – and under which conditions – DGT correlates with plant uptake. The theoretical considerations are illustrated with experimental results for metal uptake and toxicity, and for phosphorus deficiency. Strong correlations between DGT and plant uptake are predicted if the diffusive transport of the element from soil to the plant roots is rate-limiting for its uptake. If uptake is not limited by diffusive transport, DGT-fluxes and plant uptake may still correlate provided that plant uptake is not saturated. However, competitive cations may affect the plant uptake under these conditions, whereas they have no effect on the DGT flux. Moreover, labile complexes are not expected to contribute to the plant uptake if diffusion is not limiting, but they are measured with DGT. Therefore, if plant uptake is not limited by diffusion, interpretation of the observed correlation in terms of the labile species measured by DGT is inappropriate.

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Bennett, William W., Peter R. Teasdale, David T. Welsh, Jared G. Panther, Ryan R. Stewart, Helen L. Price, and Dianne F. Jolley. "Inorganic arsenic and iron(II) distributions in sediment porewaters investigated by a combined DGT–colourimetric DET technique." Environmental Chemistry 9, no. 1 (2012): 31. http://dx.doi.org/10.1071/en11074.

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Environmental contextContamination of aquatic ecosystems with inorganic arsenic is a concern for both environmental and human health. Sediments are an important sink for dissolved arsenic, but they may also act as a source of arsenic because of human-induced changes in aquatic systems. This paper describes a new approach for investigating the status of inorganic arsenic in sediments, based on recent developments in diffusion-based sediment sampling techniques. AbstractA new approach for investigating the biogeochemistry of inorganic arsenic and iron(II) in freshwater, estuarine and marine sediments is reported. The recently developed Metsorb diffusive gradients in thin films (DGT) technique for the measurement of total inorganic arsenic and the colourimetric diffusive equilibration in thin films (DET) technique for the measurement of iron(II), were utilised in combination to determine co-located depth profiles of both solutes in sediment porewaters. DGT-measured porewater arsenic concentrations were typically less than 40 nM, whereas iron(II) concentrations reached up to 704 µM. Statistically significant (P < 0.0002) correlations between porewater arsenic and iron(II) profiles were observed (R > 0.92) in mesocosms of each sediment type. This approach to investigating arsenic and iron geochemistry in sediments allows the in-situ determination of arsenic and iron species at exactly the same location in the sediment at 3-mm resolution for arsenic and 1-mm resolution for iron(II). The technique was capable of detecting very low concentrations of arsenic, with a detection limit of 0.27 nM (0.02 µg L–1) for a 48-h deployment time. Porewater iron(II), which is often present over a wide range of concentrations, was detectable up to 2000 µM. This study shows the application of these recently developed DGT and DET techniques for the in-situ investigation of inorganic arsenic and iron biogeochemistry in sediments. This approach has the potential to enable simple, yet highly representative assessment of the biogeochemical status of arsenic and iron in a variety of natural sediments, including groundwater sediments where mobilised arsenic is responsible for significant human health risks.

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Tirta, Ardina Purnama, Asep Saefumillah, Foliatini Foliatini, and Herawati Herawati. "The Study of Phosphate Release from Artificial Sediment into Water Body Using Diffusive Gradient in Thin Film (DGT) Device in Oxic Condition." Indonesian Journal of Chemistry 20, no. 2 (March 2, 2020): 395. http://dx.doi.org/10.22146/ijc.43482.

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The phenomenon of phosphate release in sediments into water bodies under oxic environment has been investigated using the Diffusive Gradient in Thin Film (DGT) technique. This research consists of several stages: polymer synthesis and DGT probe assembly, sediment sampling, DGT deployment in oxic conditions, and phosphate analysis from DGT adsorption results. Acrylamide polymer was successfully synthesized with a composition 15% acrylamide; N-N'-methylenebisacrylamide 0.1% and ferrihydrite as binding gels. DGT probes were assembly by placing a 16 x 3.2 cm polyacrylamide gel, binding gels and filter membranes on the DGT probes. The sediment sample was taken from the Bogor Botanical Gardens at the coordinates 6°36’00.6” S; 106°47’51.0” E. The DGT probe was placed in sediment samples for 1, 3 and 7 days in oxic conditions. After the prescribed time, the binding gel was removed and cut every 1 cm depth, then eluted using 0.25 M H2SO4 and the phosphate concentration was measured using spectrophotometry method. The results showed that the phosphate concentration tends to be higher with the increasing incubation time and depth. Maximum CDGT phosphate released on day 1, day 3 and day 7 were 1.00 µg/L at a depth of 14 cm, 6.61 µg/L at a depth of 14 cm, and 20.92 µg/L at a depth of 11 cm respectively. This ensures that the phosphate in water bodies comes from biogeochemical processes that occur in sediments and is successfully measured through DGT techniques.

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Fischerová, Z., J. Száková, D. Pavlíková, and P. Tlustoš. "The application of diffusive gradient technique (DGT) for assessment of changes in Cd, Pb, and Zn mobility in rhizosphere." Plant, Soil and Environment 51, No. 12 (November 20, 2011): 532–38. http://dx.doi.org/10.17221/3628-pse.

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Diffusive Gradient in Thin Films (DGT) technique was applied to determine Cd, Pb and Zn concentrations in rhizosphere of four different plant species: hyperaccumulator Penny-cress (Thlaspi caerulescens J. et C. Presl), trees with a good accumulation capacity willow (Salix dasyclados Vimm.) and poplar (Populus nigra L.) and crop maize (Zea mays L.). Moreover, the effect of two chelating agents (ethylendiaminetetraacetic acid – EDTA, and S,S-ethylendiaminedisuccinic acid – EDDS) on element mobility in rhizosphere like soil was investigated. DGT was able to register even small changes in heavy metal concentrations in rhizosphere according to individual crop and/or soil treatments. A particularly significant effect of EDTA application to enhance solubility of metals bound to solid phase into the soil solution was observed resulting in increased concentrations of mobile metals in rhizosphere. The suitability of DGT technique for evaluation of heavy metal behavior in the environment was demonstrated with reasonable results.

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Fernandes.J, Bennilo, Sivakannan S, Prabakaran N, and G. Thirugnanam. "Reversible image watermarking technique using LCWT and DGT." International Journal of Engineering & Technology 7, no. 1.3 (December 31, 2017): 42. http://dx.doi.org/10.14419/ijet.v7i1.3.9224.

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In this contemporary world procuring our confidential data against some unknown person is very significant. Thus to have a high reliability of data security watermarking technique is applied before transmitting the data. This proposed work LCWT and DGT decomposition gives an effective technique to protect hypertensive related information based on reversible watermarking. LCWT has the superiority of multi-resolution fundamental analysis of wavelet transform and reflects representation of image domain in LCT. And using DGT decomposition the patient information has to embed inside high frequency subband wavelet and the watermarked information will be extracted by the receiver without any loss, to reconstruct the original image information. The reliability of the proposed method is analyzed by comparing the experimental results of similarity index, normalization and peak signal to noise ratio.

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Town, Raewyn M., Parthasarathi Chakraborty, and Herman P. van Leeuwen. "Dynamic DGT speciation analysis and applicability to natural heterogeneous complexes." Environmental Chemistry 6, no. 2 (2009): 170. http://dx.doi.org/10.1071/en08091.

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Environmental context. The environmental fate and bioavailability of metal ions in natural waters is determined by their thermodynamic stability and kinetic features, both of which are distributed and depend on the metal ion loading of the system. Diffusive gradients in thin film (DGT) is a dynamic technique for metal speciation analysis that measures a certain portion of these complexes as determined by its operational timescale. Reliable interpretation of data furnished by DGT necessitates characterisation of its features for the particular case of heterogeneous complexes. Abstract. Owing to their inherent heterogeneity, the thermodynamic stability of metal ion complexes with natural ligands is characterised by a distribution, and thus is a function of metal-to-ligand ratio. The kinetic features of such metal complexes are also distributed and can be probed by dynamic speciation techniques. The kinetic regime of the metal complex sample can be manipulated via the metal-to-ligand ratio, and the timescale over which kinetic parameters are actually in effect is defined by the window of the chosen technique. Here we detail the kinetic features of diffusive gradients in thin film (DGT), and show that the range of attainable measurement timescales (τ) is rather limited: variation of the gel layer thickness practically allows only one order of magnitude in τ to be scanned. The more effective use of DGT to probe the distribution of dynamic metal species in heterogeneous systems is via variation of the metal-to-ligand ratio in the sample solution. Compilation of the literature DGT data for natural waters shows that by assuming a Freundlich isotherm relationship, the degree of heterogeneity is reflected in the measured DGT concentration as a function of metal ion loading.

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Wang, Peifang, Cui Liu, Yu Yao, Chao Wang, Teng Wang, Ye Yuan, and Jun Hou. "Comparison of in situ DGT measurement with ex situ methods for predicting cadmium bioavailability in soils with combined pollution to biotas." Water Science and Technology 75, no. 9 (February 21, 2017): 2171–78. http://dx.doi.org/10.2166/wst.2017.093.

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To assess the capabilities of the different techniques in predicting Cadmium (Cd) bioavailability in Cd-contaminated soils with the addition of Zn, one in situ technique (diffusive gradients in thin films; DGT) was compared with soil solution concentration and four widely used single-step extraction methods (acetic acid, EDTA, sodium acetate and CaCl2). Wheat and maize were selected as tested species. The results demonstrated that single Cd-polluted soils inhibited the growth of wheat and maize significantly compared with control plants; the shoot and root biomasses of the plants both dropped significantly (P < 0.05). The addition of Zn exhibited a strong antagonism to the physiological toxicity induced by Cd. The Pearson correlation coefficient presented positive correlations (P < 0.01, R > 0.9) between Cd concentrations in two plants and Cd bioavailability indicated by each method in soils. Consequently, the results indicated that the DGT technique could be regarded as a good predictor of Cd bioavailability to plants, comparable to soil solution concentration and the four single-step extraction methods. Because the DGT technique can offer in situ data, it is expected to be widely used in more areas.

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Huynh, Trang, Hugh H. Harris, Hao Zhang, and Barry N. Noller. "Measurement of labile arsenic speciation in water and soil using diffusive gradients in thin films (DGT) and X-ray absorption near edge spectroscopy (XANES)." Environmental Chemistry 12, no. 2 (2015): 102. http://dx.doi.org/10.1071/en14047.

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Environmental context Both inorganic and organic arsenic species are toxic to the environment when labile. The Diffusive Gradients in Thin Films technique, equipped with ferrihydrite binding gel enables measurement of labile arsenic species from water and soil solutions. This study indicated that labile arsenic species are quantitatively adsorbed to the gel, and that they are stable for up to 2 weeks following deployment. Abstract Arsenic speciation was determined in the solution extracted from a ferrihydrite binding gel layer in a DGT unit (FB-DGT) deployed in water using coupled high-performance liquid chromatography and hydride generation atomic fluorescence spectrometry (HPLC-HG-AFS). However, the extent of change in arsenic speciation during the extraction process is unknown. By identifying the arsenic species in the FB-DGT gel directly, using X-ray absorption near edge spectroscopy (XANES) fitting with model arsenic compounds, we obtain a better understanding of the ability of FB-DGT to measure labile arsenic species in solution. The results presented herein confirm that FB-DGT accumulated labile inorganic and methylated arsenic species. Arsenic species bound to the FB-DGT gel were stable for up to 2 weeks following deployment. However, caution should be applied when interpreting the proportion of As species measured by HPLC-HG-AFS in solution extracted from FB-DGT because the distribution of arsenic species in extracted solutions was found to be modified by the extraction process. Some (~20%) of arsenate was converted into arsenite, and a significant amount (~25%) of dimethylarsinic acid (DMAsV) was converted into monomethylarsonic acid (MMAsV) or arsenate (AsV). Only inorganic arsenite (iAsIII) was stable during the extraction process. These findings suggested that, based on the XANES measurement, although As species were quantitatively accumulated in the FB-DGT gel, the FB-DGT technique was still unsuitable for studying As speciation. This is because changes in arsenic speciation were observed to occur during gel extraction, prior to HPLC-HG-AFS measurement, and because the XANES technique is available for routine measurements.

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Diviš, Pavel, Marek Reichstädter, Yue Gao, Martine Leermakers, and Jakub Křikala. "Determination of Mercury in Fish Sauces by Thermal Decomposition Gold Amalgamation Atomic Absorption Spectroscopy after Preconcentration by Diffusive Gradients in Thin Films Technique." Foods 9, no. 12 (December 12, 2020): 1858. http://dx.doi.org/10.3390/foods9121858.

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The analysis of mercury in food presents a challenge for analytical chemists. Sample pre-treatment and the preconcentration of mercury prior to measurement are required, even when highly sensitive analytical methods are used. In this work, the Diffusive Gradients in Thin Films technique (DGT), combined with thermal decomposition gold amalgamation atomic absorption spectrometry (TDA-AAS), was investigated for the determination of the total dissolved mercury in fish sauces. Moreover, a new type of binding gel with Purolite S924 resin was used in DGT. Linearity assays for DGT provided determination coefficients around 0.995. Repeatability tests showed a relative standard deviation of less than 10%. pH values in the range of 3–6, as well as NaCl concentrations up to 50 g·L−1, did not affect the performance of DGT. The effective diffusion coefficient of mercury in five-fold diluted fish sauce was determined to be (3.42 ± 0.23)·10−6 cm2·s−1. Based on the 24 h deployment time of DGT, the limit of detection (LOD) for the investigated method was 0.071 µg·L−1. The proposed method, which combines DGT and TDA-AAS, allows for the analysis of fish sauces with mercury concentrations below the LOD of TDA-AAS, and significantly reduces the wear and corrosion of the TDA-AAS components.

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Nguyen, Hong Lien, Anh Tuan Phung, Trung Kien Tran, Trung Hai Huynh, and Bich Huong La. "Evaluating the Performance of a Diffusive Gradient in Thin Film Embedded with Montmorillonite for the Determination of Labile Cd, Pb, Mn, and Zn in Natural River Water." Journal of Chemistry 2020 (November 16, 2020): 1–12. http://dx.doi.org/10.1155/2020/1483909.

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Montmorillonite (MMT), a natural clay mineral with high ion-exchange capacity and trace metal adsorbability, has been demonstrated to be a suitable binding phase in the diffusive gradient in thin film (DGT) technique for the determination of labile trace metals in synthetic water samples. However, in situ working performance of DGT-MMT with natural river water has not yet been investigated. The present study examined the performance of a DGT containing montmorillonite (MMT) for the in situ isolation and determination of labile Cd, Pb, Mn, and Zn fractions in Lach Tray River water, North Vietnam. The repeatability and accuracy of the DGT-MMT probe were assessed on the basis of seven measurement replicates performed on Cd2+, Pb2+, Mn2+, and Zn2+ standard solutions. Then, the DGT-MMT probes were deployed in Lach Tray River water at different sampling sites to determine the labile metal fractions present in river water. By comparing the total and dissolved metal concentrations in the river water, the distributions of the four tested trace metals were constructed. The proportions of the dissolved fractions of Cd, Pb, Mn, and Zn were 46.7–73.7%, 38.5–63.9%, 36.4–41.6%, and 49.8–67.7%, respectively. The results also showed that the high accuracy and reproducibility of the DGT-MMT data were comparable with measurements obtained by the commonly used DGT-Chelex-100 method. In comparison with the data obtained from anodic stripping voltammetry (ASV), a traditional technique for the determination of non-in situ speciation of trace metals, labile metal concentrations measured by DGT-MMT were in similar ranges. These findings indicate that naturally available montmorillonite can be used as an alternative binding material in DGT probes for the in situ determination of labile metal concentrations in natural watercourses.

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Tiziani, Raphael, Markus Puschenreiter, Erik Smolders, Tanja Mimmo, José Carlos Herrera, Stefano Cesco, and Jakob Santner. "Millimetre-resolution mapping of citrate exuded from soil-grown roots using a novel, low-invasive sampling technique." Journal of Experimental Botany 72, no. 10 (May 4, 2021): 3513–25. http://dx.doi.org/10.1093/jxb/erab123.

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Abstract The reliable sampling of root exudates in soil-grown plants is experimentally challenging. This study aimed at developing a citrate sampling and mapping technique with millimetre-resolution using DGT (diffusive gradients in thin films) ZrOH-binding gels. Citrate adsorption kinetics, DGT capacity, and stability of ZrOH gels were evaluated. ZrOH gels were applied to generate 2D maps of citrate exuded by white lupin roots grown in a rhizotron in a phosphorus-deficient soil. Citrate was adsorbed quantitatively and rapidly by the ZrOH gels; these gels can be stored after sampling for several weeks prior to analysis. The DGT capacity of the ZrOH gel for citrate depends on the ionic strength and the pH of the soil solution, but was suitable for citrate sampling. We generated for the first time 2D citrate maps of rhizotron-grown plants at a millimetre resolution to measure an illustrated plant response to phosphorus fertilization, demonstrating that DGT-based citrate sampling is suitable for studying root exudation in soil environments, at high spatial resolution. The change of binding material would also allow sampling of other exudate classes and exudation profiles of entire root systems. These aspects are crucial in cultivar breeding and selection.

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Scally, Shaun, Hao Zhang, and William Davison. "Measurements of Lead Complexation with Organic Ligands using DGT." Australian Journal of Chemistry 57, no. 10 (2004): 925. http://dx.doi.org/10.1071/ch04076.

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The technique of diffusive gradients in thin films (DGT) was used to investigate the distribution of Pb between inorganic forms and organic complexes in various solutions that contained fulvic acid, humic acid, or nitrilotriacetic acid (NTA) over the pH range 4–8. Three types of DGT devices with diffusive gels of different pore sizes were used. When the diffusion coefficient of each species in each gel type was considered, the DGT measurements obtained agreed well with the distribution of species predicted by the ECOSAT equilibrium speciation model for all solutions and gel types. When an appreciable proportion of inorganic species was present in solution, direct measurements by DGT using the most restricted gel provided a reasonable estimate of the inorganic species in solution. This demonstrates that DGT is able to use differences in molecule mobility to distinguish between species in solution.

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Sochaczewski, Łukasz, William Davison, Hao Zhang, and Wlodeck Tych. "Understanding small-scale features in DGT measurements in sediments." Environmental Chemistry 6, no. 6 (2009): 477. http://dx.doi.org/10.1071/en09077.

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Environmental context. Observations, using the technique of diffusive gradients in thin-films (DGT), of pronounced, small-scale (millimetre) maxima in concentrations of sulfide and metals in the pore water of sediments, have emphasised the importance of processes occurring in microniches. Modelling of the interactions between microniche sources and DGT devices within a sediment environment demonstrates how these sharp features arise and provides a basis for their quantitative interpretation. Abstract. Measurements in sediments made using DGT (diffusive gradients in thin-films) have shown small-scale (millimetre and sub-millimetre) maxima in solute concentration (e.g trace metals and sulfide). The sediment–DGT system was simulated using a dynamic model, which incorporated a spherical microniche close to the DGT surface. DGT maxima could arise when the microniche was (1) a local source with associated elevated concentration in the pore water, and (2) when, within the microniche, the Kd for the relevant solute partitioning with exchangeable solute associated with the solid phase was much higher than for the rest of the sediment. Use of realistic values of Kd and comparison with existing data suggested that the latter mechanism was unlikely to be responsible for observed DGT maxima. Locally elevated concentrations will be reasonably accurately reproduced by DGT. Peak height measured by DGT will be between 62 and 87% of the true maxima in concentration within the sediment when DGT is not present, while peak widths will be similar. This work provides, for the first time, a means for confidently interpreting the two dimensional images of DGT-measured concentrations in sediments.

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Yao, Hui, Nan You, Hong-Guang Cao, Li-Xia Kang, Jin-Bao Wu, Yu-Jie Zhao, Hong-Tao Fan, and Yan-Li Yi. "In-situ sampling of available calcium using diffusive gradients in thin-films technique based on benzo-crown ether-functionalised silica as the binding agent." Environmental Chemistry 15, no. 4 (2018): 205. http://dx.doi.org/10.1071/en17228.

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Environmental contextLow availability of calcium (Ca2+) in soils is one of the major factors in Ca2+ deficiency of plants and physiological plant disorders. A device based on functionalised silica was developed for in-situ measurement of the available Ca2+ in soils. Application of the proposed device to measure available Ca2+ may help to develop and improve agricultural practices. AbstractCalcium is an ion of particular interest due to its importance in plant nutrition and soil structure. A novel device of diffusion gradients in thin-films (DGT) based on the benzo-crown ether-functionalised silica (BCES) as the binding agent and the polyethersulfone (PES) membrane as diffusive layer (BCES-DGT) was developed for in-situ sampling of available calcium (Ca2+) in freshwater and soil samples. The performance characteristics of the BCES-DGT device were assessed. The BCES was prepared using the sol-gel process and characterised by Fourier transform infrared spectroscopy, scanning electron microscopy, thermal gravimetric analysis and N2 adsorption–desorption. Results evinced that BCES was obtained successfully with a rough wrinkled surface and good specific surface area of 111.3 m2 g−1. The diffusion coefficient of Ca2+ ions in PES membrane was found to be 1.23 × 10−6 cm2 s−1 at 25 °C and was independent of pH in the range of 3–10 and ionic strength (as pNaCl) from 1 to 3. The high binding capacity of BCES binding gel for Ca2+ ions was determined to be 9822.4 ± 452.9 μg Ca2+/disk and was conducive to the deployment of long-term or high concentration. The BCES-DGT device can accurately measure the concentrations of Ca2+ over wide ranges of ionic strengths (1–3 as pNaCl) and pH (5–10). There was no significant interference on the uptake of Ca2+ by the BCES-DGT device at the tolerance limits up to 500 for Mg2+, Li+, HCO3−, H2PO4−, NO3− and SO42−, 250 for Sr2+, 2000 for K+ and 50 for fulvic acid. The results from BCES-DGT device were in excellent agreement with those measured directly using ion selective electrode in several water and soil samples. Field application in river water indicated that a good agreement was obtained between BCES-DGT value and mean grab sample measurements of Ca2+ and that the relative standard deviation of BCES-DGT measurement (4.7 %) was superior to that of grab sample measurements (13.5 %), suggesting that BCES-DGT was reliable for in-situ sampling and measurement of available Ca2+ with good accuracy and precision.

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Senila, Marin, Erika Andrea Levei, Lacrimioara Ramona Senila, and Marius Roman. "Preliminary Investigation concerning Metals Bioavailability in Waters of Aries River Catchment by Using the Diffusive Gradients in Thin Films Technique." Journal of Chemistry 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/762121.

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The paper presents the metals content and bioavailability in waters of Aries River catchment, Romania. Concentration of labile dissolved metal species measured by diffusive gradients in thin films technique (DGT), metals in colloidal and in particulate phases, and also general physical-chemical indicators of water were determined. Very high total metal concentrations were found in the tributaries that drain the mining areas. However, the influence of the polluted tributaries on the Aries River water quality was moderate, as a consequence of the tributaries low flow rate compared with that of the Aries River. Using the DGT technique the bioavailable metals fractions expressed as % of total dissolved metals concentrations were found to be 28–88% for Cu, 43–72% for Zn, 73–85% for Fe, and 33–70% for Mn. Depending on the used method for dissolved metals determination the classification of waters according to quality classes may differ. Excluding the colloidal metal fractions, DGT measures only truly dissolved metal concentrations. In cases with very high metal contamination the differences between total dissolved and DGT-labile concentrations are unimportant for waters classification. However, where the metals concentration is near the thresholds values the determination method is very important.

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Zhang, Hao, and William Davison. "Use of diffusive gradients in thin-films for studies of chemical speciation and bioavailability." Environmental Chemistry 12, no. 2 (2015): 85. http://dx.doi.org/10.1071/en14105.

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Environmental context The health of aquatic organisms depends on the distribution of the dissolved forms of chemical components (speciation) and their rates of interaction (dynamics). This review documents and explains progress made using the dynamic technique of diffusive gradients in thin-films (DGT) to meet these challenges of measuring directly chemical speciation and associated dynamics in natural waters. The relevance of these measurements to uptake by biota of chemical forms in soils, sediments and water is discussed with reference to this expanding literature. Abstract This review assesses progress in studies of chemical speciation using diffusive gradients in thin-films (DGT) by examining the contributions made by key publications in the last 20 years. The theoretical appreciation of the dynamic solution components measured by DGT has provided an understanding of how DGT measures most metal complexes, but excludes most colloids. These findings strengthen the use of DGT as a monitoring tool and provide a framework for using DGT to obtain in situ kinetic information. Generally, the capabilities of DGT as an in situ perturbation and measurement tool have yet to be fully exploited. Studies that have used DGT to investigate processes relevant to bioavailability have blossomed in the last 10 years, especially for soils, as DGT mimics the diffusion limiting uptake conditions that, under some conditions, characterise uptake by plants. As relationships between element accumulated by DGT and in plants depend on the plant species, soils studied, and the element and its chemical form, DGT is not an infallible predictive tool. Rather its strength comes from providing information on the labile species in the system, whether water, soil or sediment. Recent studies have shown good relationships between measurements of metals in periphyton and by DGT, and unified dose response curves have been obtained for biota in sediments when they are based on DGT measurements. Both these cases suggest that alternative approaches to the established ‘free ion’ approach may be fruitful in these media and illustrate the growing use of DGT to investigate environmental chemical processes.

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Diviš, Pavel, Roman Szkandera, and Hana Dočekalová. "Characterization of sorption gels used for determination of mercury in aquatic environment by diffusive gradients in thin films technique." Open Chemistry 8, no. 5 (October 1, 2010): 1105–9. http://dx.doi.org/10.2478/s11532-010-0090-3.

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AbstractThe influence of pH, ionic strength and selected natural ligands on the measurement of mercury by the diffusive gradients in thin films technique (DGT) using recently introduced sorption gels was determined. Sorption gels containing Chelex 100, Spheron-Thiol, Duolite GT73 and modified Iontosorb AV resins were investigated, with the sorption capacity determined for all used sorption gels. The minimum DGT measurable concentrations were calculated from 3 times the standard deviation of mercury amount in unexposed sorption gels.

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Ding, Shiming, Yan Wang, Liping Zhang, Lv Xu, Mengdan Gong, and Chaosheng Zhang. "New holder configurations for use in the diffusive gradients in thin films (DGT) technique." RSC Advances 6, no. 91 (2016): 88143–56. http://dx.doi.org/10.1039/c6ra19677b.

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Heidari, Saber, Adel Reyhanitabar, and Shahin Oustan. "Kinetics of phosphorus desorption from calcareous soils using DGT technique." Geoderma 305 (November 2017): 275–80. http://dx.doi.org/10.1016/j.geoderma.2017.06.012.

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Ren, Mingyi, Yan Wang, Shiming Ding, Liyuan Yang, Qin Sun, and Liping Zhang. "Development of a new diffusive gradient in the thin film (DGT) method for the simultaneous measurement of CH3Hg+ and Hg2+." New Journal of Chemistry 42, no. 10 (2018): 7976–83. http://dx.doi.org/10.1039/c8nj00211h.

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Fan, Hong-Tao, Ai-Juan Liu, Bing Jiang, Qing-Jie Wang, Tong Li, and Cong-Cong Huang. "Sampling of dissolved inorganic SbIII by mercapto-functionalized silica-based diffusive gradients in thin-film technique." RSC Advances 6, no. 4 (2016): 2624–31. http://dx.doi.org/10.1039/c5ra20163b.

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Şimşek, Arife, Şule Sancak, and Gülfem Bakan. "Monitoring of Heavy Metal Pollution in Water and Sediments at the Mid-Black Sea Region by Using Passive Sampling Method Diffusive Gradients in Thin Films." Turkish Journal of Agriculture - Food Science and Technology 9, no. 6 (July 3, 2021): 1076–86. http://dx.doi.org/10.24925/turjaf.v9i6.1076-1086.4217.

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Determining the potential bioavailability of heavy metals, evaluating according to adapted regulations is essential to efficiently conserve our coastal and estuarine waters. In this study, it is aimed to determine the industrial pollution and various other pollution sources that the Black Sea Basin is exposed to by using DGT (Diffusive Gradients in Thin Films) method and grab (manuel) sampling method in water and sediment and to evaluate the existing pollution according to quality standards. In Samsun, seasonal samples were collected from five different sampling stations, namely Akkiraz Stream, Hıdırellez Stream, Organized Industrial Zone (OIZ) Channel, Şabanoğlu Stream and Selyeri Stream, which are selected from Tekkeköy region where industry is intensively active. In order to determine the heavy metal content in both water and sediment samples, the DGT method was chosen for passive sampling and the grab sampling method was used for active sampling, and the efficiency of the methods was evaluated. According to the results of the study, the heavy metal concentration in grab sampling for water samples in descending order Al> Fe> Zn> Pb> Ni> Cu; In the samples taken with DGT, they are listed as Al> Fe> Zn> Cu> Ni> Pb. There were significant relationships between the total metal concentrations of sediment (Csed) and water (Csu) in grab sampling and metal concentrations sediment (Csed-DGT) and water (Csu-DGT) measured by DGT. It was found that the sensitivity and performance of sampling with DGT was 2-10 times higher compared to grab sampling. The high resolution in situ DGT technique for the assessment and management of the potential release risk of heavy metals at the water-sediment interface is a complementary method that contributes to the standard grab sampling method.

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Xie, Fazhi, Lu Li, Xiaoyan Sun, Tingting Hu, Kang Song, John P. Giesy, and Qilin Wang. "A novel Mg(OH)2 binding layer-based DGT technique for measuring phosphorus in water and sediment." Environmental Science: Processes & Impacts 22, no. 2 (2020): 340–49. http://dx.doi.org/10.1039/c9em00508k.

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Cornu, Jean-Yves, and Laurence Denaix. "Prediction of Zinc and Cadmium Phytoavailability Within a Contaminated Agricultural Site using DGT." Environmental Chemistry 3, no. 1 (2006): 61. http://dx.doi.org/10.1071/en05050.

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Environmental Context.In some agricultural areas, soils are contaminated by trace elements. This contamination of cultivated soils may constitute a serious problem for human health through the accumulation of metals in the edible parts of crops. In order to assess the risk for human health associated with metal contamination of soil, we need to develop simple tools like Diffusive Gradients in Thin Films (DGT) for predicting crop metal accumulation. The present study focuses on an agricultural site contaminated with fallout from industrial dust and reveals that DGT could be a predictive tool of zinc accumulation in lettuce. Abstract.Risk assessment of metal contamination in cultivated soils needs to address metal phytoavailability. The technique of diffusive gradients in thin films (DGT) has been shown to be a promising tool to assess metal phytoavailability in a wide range of soils. The present study has examined the ability of the DGT method to predict metal phytoavailability within a contaminated agricultural site. Lettuce (Lactuva sativa cv Appia) was grown in nine metal-contaminated soils differing mainly by their pH. Metal concentrations (Zn, Cd) in plant shoots were compared with total soil metal concentrations and free ion metal concentrations in soil pore waters, and effective concentrations, CE, measured by DGT. Plant Zn concentrations were highly related to CE, suggesting DGT can be a sensitive tool able to assess Zn phytoavailability within mildly contaminated agricultural soils. Plant Cd concentrations were less closely related to CE, signifying that processes other than Cd re-supply from the solid phase may occur during soil–plant transfer of Cd.

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Galceran, Josep, and Jaume Puy. "Interpretation of diffusion gradients in thin films (DGT) measurements: a systematic approach." Environmental Chemistry 12, no. 2 (2015): 112. http://dx.doi.org/10.1071/en14068.

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Environmental context Dynamic speciation of an element in a natural medium is essential for understanding its availability. The technique of diffusion gradients in thin films (DGT) has become a widely used tool for in situ environmental studies, being applied to determine fluxes of metal cations, anions, organics and nanoparticles. The interpretation of the measurements with suitable physicochemical models gives valuable insights into the behaviour of the system. Abstract Gaining insight into the physicochemical processes integrated in a DGT (diffusion gradients in thin films) measurement and combining them in a model can assist in retrieving fundamental information, both qualitative and quantitative, on the probed system. New experiments (such as varying the thicknesses of the gel or the resin layer) and their mathematical treatment to extract meaningful parameters have been suggested from theoretical considerations. The concept of lability degree is useful in describing an interpretation of the DGT concentration as the summation of the free metal concentration plus the labile fraction of all complexes multiplied by a ratio of diffusion coefficients. In some cases, the lability degree can be directly estimated with specific measurements and a very simple expression. We review the current status of these interpretations, including numerical simulations, with special focus on analytical expressions, because they can be more accessible to the standard DGT practitioner. Present limitations and challenges for future work in DGT interpretation are also discussed.

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Rochereau, P., and A. Bernardé. "Stabilization of coxo-femoral luxation using tenodesis of the deep gluteal muscle." Veterinary and Comparative Orthopaedics and Traumatology 25, no. 01 (2012): 49–53. http://dx.doi.org/10.3415/vcot-10-12-0168.

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SummaryThis retrospective study documents deep gluteal tenodesis (DGT) used to stabilize coxofemoral luxation (CFL) in dogs and cats, and to report reluxation rate and clinical outcome after DGT.Medical records (1995–2008) of 65 dogs and cats with traumatic CFL treated by capsulorrhaphy and DGT were reviewed. Animals with radiographic evidence of pre-existing hip dysplasia or articular fractures had been excluded. Reluxation rate and outcome were assessed by clinical examination, performed two and ten weeks postoperatively.Surgical treatment was performed between one and 20 days after the initiating event. No perioperative complications occurred. All hip joints were correctly reduced and stabilized immediately after DGT completion. Except for five patients, placement of the screw was considered correct. In two of these patients, the screws were too long and were protruding into the pelvic canal. In two dogs, the screws were not tightened adequately, and in one dog the screw was too short. Twenty-six dogs and eight cats were re-examined between eight and 13 weeks postoperatively. Reluxation did not occur in any of them. Outcomes were good in two cases and excellent in 32 cases; all but two had a normal range-of-motion of the reconstructed hip, and were free of lameness and did not show any signs of pain.Traumatic CFL can be stabilized safely and effectively by DGT in dogs and cats. This technique should be considered among other capsular reinforcement techniques in the presence of an intact deep gluteal muscle.Presented in part at the 19th Annual Scientific Meeting ECVS, Helsinki, Finland, July 1–3, 2010

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Sun, Qin, Liping Zhang, Shiming Ding, Chao Li, Jinyan Yang, Jing Chen, and Peifang Wang. "Evaluation of the diffusive gradients in thin films technique using a mixed binding gel for measuring iron, phosphorus and arsenic in the environment." Environmental Science: Processes & Impacts 17, no. 3 (2015): 570–77. http://dx.doi.org/10.1039/c4em00629a.

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Simultaneous measurements of dissolved iron (Fe), phosphorus (P), and arsenic (As) were made using the diffusive gradients in thin films technique equipped with a mixed binding gel impregnated with zirconium oxide and Chelex-100 (ZrO–Chelex DGT).

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Shiva, Amir Houshang, Peter R. Teasdale, David T. Welsh, and William W. Bennett. "Evaluation of the DGT technique for selective measurement of aluminium and trace metal concentrations in an acid drainage-impacted coastal waterway." Environmental Science: Processes & Impacts 19, no. 5 (2017): 742–51. http://dx.doi.org/10.1039/c6em00276e.

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Rumhayati, Barlah, Chasan Bisri, and Wahyu O. Fajarina. "THE PERFORMANCE OF CHITOSAN-FERRIHIDRYTE MEMBRANE FOR PHOSPHATE UPTAKE." Indonesian Journal of Chemistry 9, no. 3 (June 24, 2010): 404–9. http://dx.doi.org/10.22146/ijc.21506.

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The uptake of orthophosphate onto the chitosan-ferrihydrite membrane has been studied. The membrane was proposed as a new binding layer of DGT technique. Membrane was prepared from a mixture of chitosan solution with ferrihydrite (FeOOH) paste and was crosslinked with glutaraldehyde. As a result, the uptake of orthophosphate was slow. The maximum adsorption capacity was reached at pH 5.0 and 8.0. It was mainly due to electrostatic attraction of phosphate ions to the protonated free amino groups of chitosan and to active sites of ferrihydrite. Desorption could be occurred optimally using 0.3 M of sulphuric acid. The absorption of SO42- ion to the protonated amino groups and the formation of ionic crosslinking could exchange and desorb phosphate ions. Ferrihydrite was eluted also by the acid. However, the eluted ferrihydrite readsorbed phosphate ions, resulted in minimizing the analysed free phosphate. Keywords: adsorption, phosphate, chitosan-ferrihydrite/glutaraldehide membrane, DGT technique

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Laera, Andreina, Rémy Buzier, Gilles Guibaud, Giovanni Esposito, and Eric D. van Hullebusch. "Assessment of the DGT technique in digestate to fraction twelve trace elements." Talanta 192 (January 2019): 204–11. http://dx.doi.org/10.1016/j.talanta.2018.09.033.

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Kong, Hyung-Yun, Ho Van Khuong, and Doo-Hee Nam. "PAPR Reduction Improvement for WHT-based OFDM System using Data Grouping Technique." KIPS Transactions:PartC 12C, no. 4 (August 1, 2005): 511–18. http://dx.doi.org/10.3745/kipstc.2005.12c.4.511.

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Wang, Jinjin, Lingyu Bai, Xibai Zeng, Shiming Su, Yanan Wang, and Cuixia Wu. "Assessment of arsenic availability in soils using the diffusive gradients in thin films (DGT) technique—a comparison study of DGT and classic extraction methods." Environ. Sci.: Processes Impacts 16, no. 10 (2014): 2355–61. http://dx.doi.org/10.1039/c4em00215f.

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Noviardi, Febri, Andre Noevi Rahmanto, and Yulius Slamet. "Logo rebranding: Indonesian tax authority public relations strategy in forming organizational culture images." Informasi 50, no. 1 (August 4, 2020): 30–45. http://dx.doi.org/10.21831/informasi.v50i1.29594.

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This paper explains how the process of rebranding the logo of the Directorate General of Taxes (DGT) of the Republic of Indonesia carried out by DGT public relations in shaping the image by displaying the cultural values of the Ministry of Finance. This is motivated by the lack of a comprehensive explanation of the process of rebranding the logo in previous studies. At DGT, logo rebranding is carried out because of the low level of the public’s trust in the DGT. Therefore, one of the strategies of the DGT public relations is the formation of an institutional image. This study uses a research method with a qualitativeapproach with data collection conducted by interviewing selected informants using purposive sampling techniques and source triangulation as a technique in testing the validity of the data. The results are analyzed using the Assessment, Communication and Analysis, Design, and Action planning model. The rebranding process was 1) describing the problem, 2) using all channels communication and objectives in delivering a new logo, 3) using professional consultants in planning that consist of research, strategy development, and implementation, 4) as well as carrying out plans, setting rules, and supervising all activities in the DGT’s rebranding process.Tulisan ini menjelaskan bagaimana proses rebranding logo Direktorat Jenderal Pajak (DJP) RI yang dilakukan oleh Humas DJP dalam membentuk citra dengan menampilkan nilainilai budaya organisasi Kemenkeu. Hal ini dilatarbelakangi oleh kurangnya penjelasan yang komprehensif terhadap proses rebranding logo pada studi-studi sebelumnya. Pada DJP, rebranding logo dilakukan karena rendahnya tingkat kepercayaan masyarakat terhadap DJP. Oleh karena itu, salah satu strategi Public Relations (PR) adalah dengan pembentukan citra institusi. Penelitian ini menggunakan metode penelitian dengan pendekatan kualitatif dengan pengumpulan data dilakukan dengan cara wawancarakepada informan terpilih menggunakan teknik purposive sampling dan triangulasi sumber sebagai teknik dalam uji keabsahan datanya. Hasilnya dianalisis menggunakan model perencanaan Assessment, Communication and Analysis, Design, dan Action. Proses rebranding yang dilakukan yaitu 1) menggambarkan masalah, 2) menggunakan semua saluran komunikasi dan tujuan dalam memberikan logo baru, 3) menggunakan konsultan profesional dalam perencanaan yang terdiri dari penelitian, pengembangan strategi, dan implementasi, 4) serta melaksanakan perencanaan, menetapkan aturan,dan melakukan pengawasan terhadap seluruh kegiatan pada proses rebranding Ditjen Pajak RI.

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Davison, William, and Hao Zhang. "Progress in understanding the use of diffusive gradients in thin films (DGT) – back to basics." Environmental Chemistry 9, no. 1 (2012): 1. http://dx.doi.org/10.1071/en11084.

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Environmental contextIt is now nearly 20 years since the introduction of the technique of diffusive gradients in thin films, which can provide information on solute concentrations and dynamics in sediments, soils and water. The interpretation of these measurements in terms of concentrations relies on simple equations and associated assumptions. This review examines how well they have stood the test of time. AbstractDiffusive gradients in thin films (DGT) is now widely used to measure a range of determinands in waters, soils and sediments. In most cases the mass accumulated is interpreted in terms of a labile form of the component being measured using a simple equation that applies to steady-state conditions. During the past decade several publications have revealed phenomena that question some of the assumptions necessary for use of the simple equation. This review systematically examines the available evidence relating to appropriate geometry, possible charge effects, binding of solutes and ligands to the diffusive gel and filter, the rate of reaction with the binding layer, the effects of solution complexation and kinetic limitation, necessary time for deployment and the measurement of nanoparticles. DGT emerges as a robust monitoring tool for labile components in solution. Although there is evidence, for some conditions, of binding of metals and, more moderately, humic substances to the diffusive gel and filter membrane, this is unlikely to affect DGT measurement in natural waters for deployment times exceeding a few days. Detailed speciation and kinetic studies require a more thorough interpretation of the mass accumulated by DGT. A coherent theory has emerged for relatively simple solutions, but systems with complex heterogeneous ligands, as is the case for natural waters, are challenging. The size discrimination of DGT is still poorly known. Systematic measurements with well characterised nanoparticles are required to define the distribution of pore sizes in the gels and to establish the contribution of natural colloids to the DGT measurement.

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Clarisse, O., G. R. Lotufo, H. Hintelmann, and E. P. H. Best. "Biomonitoring and assessment of monomethylmercury exposure in aqueous systems using the DGT technique." Science of The Total Environment 416 (February 2012): 449–54. http://dx.doi.org/10.1016/j.scitotenv.2011.11.077.

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Iqbal, Shahzad. "The Role of Double Guidewire Technique (DGT) in Difficult Biliary Cannulation: A Review." American Journal of Gastroenterology 105 (October 2010): S536—S537. http://dx.doi.org/10.14309/00000434-201010001-01444.

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Kazekawa, K., K. Oka, H. Aikawa, M. Tomonaga, S. Yoshimura, T. Yoshioka, and H. Hosoda. "How to Embolize Wide-Necked Aneurysms?" Interventional Neuroradiology 5, no. 1_suppl (November 1999): 103–8. http://dx.doi.org/10.1177/15910199990050s119.

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Novel endovascular approaches are needed for safer and more definitive treatment of wide-necked aneurysms, to overcome the limitations of the Guglielmi detachable coil (GDC) system and further, the application of this technique. The double GDC technique (DGT), for embolization of wide-necked aneurysms, and the combination of stent placement and coil deposition (CTSC) for management of fusiform aneurysms have been developed and their usefulness is reviewed. The DGT involves scaffolding of a GDC coil to form a stabilizing frame inside the aneurysmal neck and then positioning of a second coil to reinforce the first coil. After confirming the absence of coil herniation in the parent artery, both coils are released together. A patient with a wide-necked large aneurysm of the left internal carotid artery was treated using this technique, and followed up angiographically and clinically for a period of three months. The follow-up angiograms revealed complete embolization of the aneurysm. The patient had no neurological changes or adverse events during the procedure. The CTSC involves reconstructing the artery with a stent and packing the aneurysm lumen with GDCs through the stent interstices. A patient with a dissecting fusiform aneurysm of the vertebral artery associated with hypoplasia of the contralateral vertebral artery was treated using this technique to prevent rebleeding. His clinical course was uneventful over a six-month follow-up period. Angiography performed two months after the procedure confirmed excellent flow through the right vertebral artery and absence of filling of the daughter aneurysm.

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Maimulyanti, Askal, Budiawan Budiawan, Asep Saefumillah, and Heny Suseno. "Effect of Salinity and Oxygen Condition on Phosphate Release from Marine Sediment Measured Using Diffusive Gradient in Thin Film (DGT) Technique." Indonesian Journal of Chemistry 19, no. 3 (May 29, 2019): 615. http://dx.doi.org/10.22146/ijc.35233.

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The diffusive gradient in thin film (DGT) is an analytical technique to determine phosphate in the environment. This technique uses a thin film diffusive hydrogel in contact with a binding phase (ferrihydrite) to binding of phosphate. The released phosphate from marine sediment of Jakarta Bay was studied by DGT technique for effect of salinity and oxygen condition. Effect of salinity was observed by NaCl concentration from 0-35 g/L. The maximum phosphate release from sediment was occurred at the concentration of NaCl 30 g/L with incubation for 15 days with phosphate released at 113.99 μg/L, MDGT of 4.7723 μg and CDGT of 17.56 μg/L. The experiment showed the increase of MgCl2 and CaCl2 concentration reduced phosphate release from sediment. The condition of oxygen indicating the release of phosphate under anaerobic conditions is greater than the aerobic condition. The aerobic conditions with incubation for 21 days showed the release of phosphate from sediment to overlying water of 124.72 μg/L, MDGT of 2.4492 μg and CDGT of 6.4380 μg/L. Anaerobic conditions with incubation for 21 days showed phosphate release from sediment to overlying water of 208.62 μg/L, MDGT of 6.1081 μg and CDGT of 16.06 μg/L. The experiment shows that salinity and oxygen concentration influences phosphate release from marine sediment of Jakarta Bay.

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Xu, Lv, Qin Sun, Shiming Ding, Mengdan Gong, and Chaosheng Zhang. "Simultaneous measurements of arsenic and sulfide using diffusive gradients in thin films technique (DGT)." Environmental Geochemistry and Health 40, no. 5 (May 5, 2017): 1919–29. http://dx.doi.org/10.1007/s10653-017-9968-8.

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Guibal, Robin, Rémy Buzier, Adeline Charriau, Sophie Lissalde, and Gilles Guibaud. "Passive sampling of anionic pesticides using the Diffusive Gradients in Thin films technique (DGT)." Analytica Chimica Acta 966 (May 2017): 1–10. http://dx.doi.org/10.1016/j.aca.2017.02.007.

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Singh, Ravinder, Archana Khurana, and Sunil Kumar. "Optimized 3D laser point cloud reconstruction by gradient descent technique." Industrial Robot: the international journal of robotics research and application 47, no. 3 (February 15, 2020): 409–21. http://dx.doi.org/10.1108/ir-12-2019-0244.

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Purpose This study aims to develop an optimized 3D laser point reconstruction using Descent Gradient algorithm. Precise and accurate reconstruction of 3D laser point cloud of the complex environment/object is a key solution for many industries such as construction, gaming, automobiles, aerial navigation, architecture and automation. A 2D laser scanner along with a servo motor/pan tilt/inertial measurement unit is used for generating 3D point cloud (either environment/object or both) by acquiring the real-time data from sensors. However, while generating the 3D laser point cloud, various problems related to time synchronization problem between laser and servomotor and torque variation in servomotors arise, which causes misalignment in stacking the 2D laser scan for generating the 3D point cloud of the environment. Because of the misalignment in stacking, the 2D laser scan corresponding to the erroneous angular and position information by the servomotor and the 3D laser point cloud become distorted in terms of inconsistency for measuring the dimension of the objects. Design/methodology/approach This paper addresses a modified 3D laser system assembled from a 2D laser scanner coupled with a servomotor (dynamixel motor) for developing an efficient 3D laser point cloud with the implementation of an optimization technique: descent gradient filter (DGT). The proposed approach reduces the cost function (error) in the angular and position coordinates of the servo motor caused because of torque variation and time synchronization, which resulted in enhancing the accuracy in 3D point cloud mapping for the accurate measurement of the object’s dimensions. Findings Various real-world experiments are performed with the proposed DGT filter linked with laser scanner and servomotor and an improvement of 6.5 per cent in measuring the accurate dimension of object is obtained while comparing with conventional approaches for generating a 3D laser point cloud. Originality/value This proposed technique may be applicable for various industrial applications that are based on robotics arms (such as painting, welding and cutting) in the automobile industry, the optimized measurement of object, efficient mobile robot navigation, precise 3D reconstruction of environment/object in construction, architecture applications, airborne applications and aerial navigation.

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Stockdale, Anthony, William Davison, and Hao Zhang. "High-resolution two-dimensional quantitative analysis of phosphorus, vanadium and arsenic, and qualitative analysis of sulfide, in a freshwater sediment." Environmental Chemistry 5, no. 2 (2008): 143. http://dx.doi.org/10.1071/en07096.

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Environmental context. Chemical characterisation of sediment microniches can reveal diagenetic processes that may not be detected by larger-scale analysis. With the development of a new preparation method for a binding phase gel, the technique of diffusive gradients in thin films has been used to demonstrate links between the diagenesis of sulfide, phosphorus, vanadium and arsenic at microniches. Knowledge of these processes may improve predictions of past deposition climates where trace elements are considered as paleoredox proxies. Abstract. Recently introduced techniques that can provide two-dimensional images of solution concentrations in sediments for multiple analytes have revealed discrete sites of geochemical behaviour different from the average for that depth (microniches). We have developed a new preparation method for a binding phase, incorporated in a hydrogel, for the diffusive gradients in thin films (DGT) technique. It allows co-analysis of sulfide and the reactive forms of phosphorus, vanadium and arsenic in the porewaters at the surface of the device. This gel, when dried and analysed using laser ablation mass spectrometry, allows the acquisition of high-resolution sub-millimetre-scale data. The binding phase was deployed within a DGT device in a sediment core collected from a productive lake, Esthwaite Water (UK). Localised removal of phosphate and vanadium from the porewaters has been demonstrated at a microniche of local sulfide production. The possible removal processes, including bacterial uptake and reduction of vanadate to insoluble VIII by sulfide, are discussed. Understanding processes occurring at this scale may allow improved prediction of pollutant fate and better prediction of past climates where trace metals are used as paleoredox proxies.

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Weng, Zhe, Michael T. Rose, Ehsan Tavakkoli, Lukas Van Zwieten, Gavin Styles, William Bennett, and Enzo Lombi. "Assessing plant-available glyphosate in contrasting soils by diffusive gradient in thin-films technique (DGT)." Science of The Total Environment 646 (January 2019): 735–44. http://dx.doi.org/10.1016/j.scitotenv.2018.07.221.

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Kalkhajeh, Yusef Kianpoor, Helle Sørensen, Biao Huang, Dong-Xing Guan, Jun Luo, Wenyou Hu, Peter E. Holm, and Hans Christian Bruun Hansen. "DGT technique to assess P mobilization from greenhouse vegetable soils in China: A novel approach." Science of The Total Environment 630 (July 2018): 331–39. http://dx.doi.org/10.1016/j.scitotenv.2018.02.228.

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Saefumilla, Asep, Askal Maimulyant, Budiawan ., and Heny Suseno. "Bioavailability of Phosphate to Microalgae Oscillatoria sp. with Diffusive Gradient in Thin Film (DGT) Technique." Journal of Environmental Science and Technology 12, no. 5 (August 15, 2019): 205–12. http://dx.doi.org/10.3923/jest.2019.205.212.

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Vogel, Christian, Marie C. Hoffmann, Oliver Krüger, Vadim Murzin, Wolfgang Caliebe, and Christian Adam. "Chromium (VI) in phosphorus fertilizers determined with the diffusive gradients in thin-films (DGT) technique." Environmental Science and Pollution Research 27, no. 19 (April 18, 2020): 24320–28. http://dx.doi.org/10.1007/s11356-020-08761-w.

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Yapici, Tahir, Ismail I. Fasfous, John Murimboh, and Chuni L. Chakrabarti. "Investigation of DGT as a metal speciation technique for municipal wastes and aqueous mine effluents." Analytica Chimica Acta 622, no. 1-2 (August 2008): 70–76. http://dx.doi.org/10.1016/j.aca.2008.05.061.

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Journal articles on the topic 'The DGT technique'

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