Relevant bibliographies by topics / Breakthrough curve analysis / Journal articles

To see the other types of publications on this topic, follow the link: Breakthrough curve analysis.

Journal articles on the topic 'Breakthrough curve analysis'

Author: Grafiati

Published: 4 June 2021

Last updated: 1 February 2022

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 journal articles for your research on the topic 'Breakthrough curve analysis.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.

Knox, James C., Armin D. Ebner, M. Douglas LeVan, Robert F. Coker, and James A. Ritter. "Limitations of Breakthrough Curve Analysis in Fixed-Bed Adsorption." Industrial & Engineering Chemistry Research 55, no. 16 (2016): 4734–48. http://dx.doi.org/10.1021/acs.iecr.6b00516.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Sharp, R. R., A. B. Cunningham, J. Komlos, and J. Billmayer. "Observation of thick biofilm accumulation and structure in porous media and corresponding hydrodynamic and mass transfer effects." Water Science and Technology 39, no. 7 (1999): 195–201. http://dx.doi.org/10.2166/wst.1999.0359.

Full text

Abstract:

A series of flat plate, porous media reactor studies was performed to characterize the development and structure of thick biofilms in porous media and the subsequent effects on porous media hydrodynamics and mass transport variables including average pore velocity, hydrodynamic dispersivity, and (dye tracer) breakthrough curve features. Biofilms composed of either a mucoid strain of Pseudomonas aeruginosa or a non-mucoid strain of Ps. aeruginosa were established in the reactors over a 2-3 week period. Analysis of porous media biofilms was performed using a combination of image analysis, photography, microbial vital stains, enumerations, and microscopy. Bulk fluid flow and flow channel distribution in the porous media/biofilm matrix were monitored by imaging a pulse of nigrosine dye. Hydrodynamics of the systems were determined by evaluating fluorescein dye breakthrough curves. Destructive sampling of the flat plate reactors at the end of each study provided additional information on the distribution and cell density of the porous media biofilms. Imaging results indicated the creation and closure of flow channels within the biofilm/porous media matrix for both mucoid and non-mucoid strains. Both systems exhibited accelerated tracer breakthrough and slightly increased hydrodynamic dispersivity as the biofilm matrix developed. Gray scale analysis of nigrosine pulses, along with fluorescein dye studies, suggests that biofilm development transforms the flow regime within the reactor from well defined porous media flow with a symmetric breakthrough curve to a skewed breakthrough curve with accelerated time to breakthrough.

APA, Harvard, Vancouver, ISO, and other styles

Marciniak, Marek, Monika Okońska, and Mariusz Kaczmarek. "Preselection of a sorption model based on a column test: the algorithm and an example of its application." Hydrogeology Journal 29, no. 4 (2021): 1551–67. http://dx.doi.org/10.1007/s10040-021-02338-8.

Full text

Abstract:

AbstractIn order to describe the contamination of saturated porous media, it is necessary to find an appropriate mathematical model that includes processes occurring in aquifers, such as advection, dispersion, diffusion, and various kinds of sorption. The identification of parameters of those processes is possible through laboratory column experiments, which result in records of breakthrough curves for a conservative tracer and a reactive tracer. An algorithm leading to the preliminary selection of the mathematical model that best describes transport processes of the reactive tracer in the experimental column is proposed in this article. A study published previously presented a sensitivity analysis for an arbitrarily adopted variability of the transport parameters. The analysis involved examining changes in the shape of breakthrough curves caused by the alteration of each parameter value. Specially defined indicators called descriptors were proposed to quantitatively describe the breakthrough curves. Then, formulas were proposed to determine the percentage deviations of descriptors of the breakthrough curve obtained for the reactive tracer in relation to the descriptors of the breakthrough curve of the conservative tracer. In the work described in this article, the deviations are analyzed and an algorithm is proposed that allows the preselection of the most suitable sorption model out of the five discussed simple (one-site) and six hybrid (two-site) models. The algorithm can facilitate and accelerate the interpretation of column experiments of contaminant transport in a porous medium. An example is provided to illustrate the usability of the proposed algorithm.

APA, Harvard, Vancouver, ISO, and other styles

Kotoh, K., M. Tanaka, T. Sakamoto, et al. "Breakthrough Curve Analysis of Pressure Swing Adsorption for Hydrogen Isotope Separation." Fusion Science and Technology 54, no. 2 (2008): 415–18. http://dx.doi.org/10.13182/fst08-a1843.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Rajeshkannan, R., M. Rajasimman, and N. Rajamohan. "Packed bed column studies for the removal of dyes using novel sorbent." Chemical Industry and Chemical Engineering Quarterly 19, no. 4 (2013): 461–70. http://dx.doi.org/10.2298/ciceq120407081r.

Full text

Abstract:

A continuous fixed bed study was carried out by using tamarind seed as a sorbent for the removal of malachite green (MG) and acid blue 9(AB9) from aqueous solution. The effect of factors, such as flow rate and bed depth was studied. Data confirmed that the breakthrough curves were dependent on flow rate and bed depth. Thomas, Adams-Bohart, and Yoon-Nelson models were applied to experimental data to predict the breakthrough curves using non-linear regression and to determine the characteristic parameters of the packed bed column. Bed depth/service time analysis (BDST) model was used to express the effect of bed depth on breakthrough curves. The results showed that Thomas model was found suitable for the normal description of breakthrough curve at the experimental condition, while Adams-Bohart and Yoon-Nelson model were able to explain only the initial part of dynamic behaviour of the tamarind seed column. The data were in good agreement with BDST model. It was concluded that the tamarind seed can be effectively used as a sorbent for the removal of dyes.

APA, Harvard, Vancouver, ISO, and other styles

Nienow, Peter W., Martin Sharp, and Ian С. Willis. "Sampling-rate effects on the properties of dye breakthrough curves from glaciers." Journal of Glaciology 42, no. 140 (1996): 184–89. http://dx.doi.org/10.1017/s0022143000030641.

Full text

Abstract:

AbstractDye-tracer techniques are widely used in infer the character of subglacial drainage systems. Quantitative analysis of dye breakthrough curves focuses on the determination of the water through flow velocity(u),the dispersion coefficient(D)and the dispersivity parameter(d = D/u). Together, these parameters describe the rate of passage of tracer through the drainage system and the extent to which the dye cloud becomes spread out during passage. They have been used to infer the nature of flow conditions within a drainage system and temporal changes in system morphology. Estimates of all three parameters, however, are dependent upon the sampling interval at which measurements of dye concentration used to define breakthrough curves are made. For a given breakthrough curve, the dispersion coefficient increases with the sampling interval, while the through flow velocity shows no systematic variation. As a result, the dispersivity also tends to increase with the sampling interval. Investigations of the sensitivity of parameter estimates to the sampling interval reveal that reliable estimates can be obtained only if the sampling interval is less than 1/16 of the time from dye injection to peak dye concentration. As a general guide, we Suggest that, ideally, quantitative analyses of dye breakthrough curves should therefore be conducted only when this criterion can be met.

APA, Harvard, Vancouver, ISO, and other styles

Full text

Abstract:

AbstractDye-tracer techniques are widely used in infer the character of subglacial drainage systems. Quantitative analysis of dye breakthrough curves focuses on the determination of the water through flow velocity (u), the dispersion coefficient (D) and the dispersivity parameter (d = D/u). Together, these parameters describe the rate of passage of tracer through the drainage system and the extent to which the dye cloud becomes spread out during passage. They have been used to infer the nature of flow conditions within a drainage system and temporal changes in system morphology. Estimates of all three parameters, however, are dependent upon the sampling interval at which measurements of dye concentration used to define breakthrough curves are made. For a given breakthrough curve, the dispersion coefficient increases with the sampling interval, while the through flow velocity shows no systematic variation. As a result, the dispersivity also tends to increase with the sampling interval. Investigations of the sensitivity of parameter estimates to the sampling interval reveal that reliable estimates can be obtained only if the sampling interval is less than 1/16 of the time from dye injection to peak dye concentration. As a general guide, we Suggest that, ideally, quantitative analyses of dye breakthrough curves should therefore be conducted only when this criterion can be met.

APA, Harvard, Vancouver, ISO, and other styles

Zhong, Qian-Qian, Xing Xu, Li Shen, Ya-Jing Han, and Yu-Cui Hao. "Breakthrough Curve Analysis of Enteromorpha prolifera Packed Fixed-Bed Column for the Biosorption." Environmental Engineering Science 35, no. 8 (2018): 864–74. http://dx.doi.org/10.1089/ees.2017.0473.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Kwon, Siyoon, Hyoseob Noh, Il Won Seo, Sung Hyun Jung, and Donghae Baek. "Identification Framework of Contaminant Spill in Rivers Using Machine Learning with Breakthrough Curve Analysis." International Journal of Environmental Research and Public Health 18, no. 3 (2021): 1023. http://dx.doi.org/10.3390/ijerph18031023.

Full text

Abstract:

To minimize the damage from contaminant accidents in rivers, early identification of the contaminant source is crucial. Thus, in this study, a framework combining Machine Learning (ML) and the Transient Storage zone Model (TSM) was developed to predict the spill location and mass of a contaminant source. The TSM model was employed to simulate non-Fickian Breakthrough Curves (BTCs), which entails relevant information of the contaminant source. Then, the ML models were used to identify the BTC features, characterized by 21 variables, to predict the spill location and mass. The proposed framework was applied to the Gam Creek, South Korea, in which two tracer tests were conducted. In this study, six ML methods were applied for the prediction of spill location and mass, while the most relevant BTC features were selected by Recursive Feature Elimination Cross-Validation (RFECV). Model applications to field data showed that the ensemble Decision tree models, Random Forest (RF) and Xgboost (XGB), were the most efficient and feasible in predicting the contaminant source.

APA, Harvard, Vancouver, ISO, and other styles

Mekonnen, Dereje Tadesse, Esayas Alemayehu, and Bernd Lennartz. "Fixed-Bed Column Technique for the Removal of Phosphate from Water Using Leftover Coal." Materials 14, no. 19 (2021): 5466. http://dx.doi.org/10.3390/ma14195466.

Full text

Abstract:

The excessive discharge of phosphate from anthropogenic activities is a primary cause for the eutrophication of aquatic habitats. Several methodologies have been tested for the removal of phosphate from aqueous solutions, and adsorption in a flow-through reactor is an effective mechanism to reduce the nutrient loading of water. This research aimed to investigate the adsorption potential of leftover coal material to remove phosphate from a solution by using continuous flow fixed-bed column, and analyzes the obtained breakthrough curves. A series of column tests were performed to determine the phosphorus breakthrough characteristics by varying operational design parameters such as adsorbent bed height (5 to 8 cm), influent phosphate concentration (10–25 mg/L), and influent flow rate (1–2 mL/min). The amorphous and crystalline property of leftover coal material was studied using XRD technology. The FT-IR spectrum confirmed the interaction of adsorption sites with phosphate ions. Breakthrough time decreased with increasing flow rate and influent phosphate concentration, but increased with increasing adsorbent bed height. Breakthrough-curve analysis showed that phosphate adsorption onto the leftover coal material was most effective at a flow rate of 1 mL/min, influent phosphate concentration of 25 mg/L, and at a bed height of 8 cm. The maximal total phosphate adsorbed onto the coal material’s surface was 243 mg/kg adsorbent. The Adams–Bohart model depicted the experimental breakthrough curve well, and overall performed better than the Thomas and Yoon–Nelson models did, with correlation values (R2) ranging from 0.92 to 0.98. Lastly, leftover coal could be used in the purification of phosphorus-laden water, and the Adams–Bohart model can be employed to design filter units at a technical scale.

APA, Harvard, Vancouver, ISO, and other styles

Kamble, Manisha G., Milind D. Nagrale, Ankit A. Kamdi, Sunil K. Deokar, and Sachin A. Mandavgane. "Packed column dynamic studies and breakthrough curve analysis for adsorption of paraquat herbicide onto agroindustrial ashes." DESALINATION AND WATER TREATMENT 83 (2017): 86–97. http://dx.doi.org/10.5004/dwt.2017.21043.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Samarghandi, Mohammad R., Mahdi Hadi, and Gordon McKay. "Breakthrough Curve Analysis for Fixed-Bed Adsorption of Azo Dyes Using Novel Pine Cone—Derived Active Carbon." Adsorption Science & Technology 32, no. 10 (2014): 791–806. http://dx.doi.org/10.1260/0263-6174.32.10.791.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Prattes, Jürgen, Wiebke Duettmann, and Martin Hoenigl. "Posaconazole Plasma Concentrations on Days Three to Five Predict Steady-State Levels." Antimicrobial Agents and Chemotherapy 60, no. 9 (2016): 5595–99. http://dx.doi.org/10.1128/aac.00389-16.

Full text

Abstract:

ABSTRACTLow posaconazole plasma concentrations (PPCs) have been associated with breakthrough invasive fungal infections. We assessed the correlation between pre-steady-state PPCs (obtained between days 3 and 5) and PPCs obtained during steady state in 48 patients with underlying hematological malignancies receiving posaconazole oral-solution prophylaxis. Pre-steady-state PPCs correlated significantly with PPCs obtained at steady state (Spearmanr= 0.754;P< 0.001). Receiver operating characteristic (ROC) curve analysis of pre-steady-state PPCs revealed an area under the curve (AUC) of 0.884 (95% confidence interval [CI], 0.790 to 0.977) for predicting satisfactory PPCs at steady state.

APA, Harvard, Vancouver, ISO, and other styles

Motshekga, Sarah C., and Suprakas Sinha Ray. "Highly efficient inactivation of bacteria found in drinking water using chitosan-bentonite composites: Modelling and breakthrough curve analysis." Water Research 111 (March 2017): 213–23. http://dx.doi.org/10.1016/j.watres.2017.01.003.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Jacobsen, Ole H., Feike J. Leij, and Martinus Th van Genuchten. "Parameter Determination for Chloride and Tritium Transport in Undisturbed Lysimeters during Steady Flow." Hydrology Research 23, no. 2 (1992): 89–104. http://dx.doi.org/10.2166/nh.1992.0007.

Full text

Abstract:

Breakthrough curves of Cl and 3H2O were obtained during steady unsaturated flow in five lysimeters containing an undisturbed coarse sand (Orthic Haplohumod). The experimental data were analyzed in terms of the classical two-parameter convection-dispersion equation and a four-parameter two-region type physical nonequilibrium solute transport model. Model parameters were obtained by both curve fitting and time moment analysis. The four-parameter model provided a much better fit to the data for three soil columns, but performed only slightly better for the two remaining columns. The retardation factor for Cl was about 10 % less than for 3H2O, indicating some anion exclusion. For the four-parameter model the average immobile water fraction was 0.14 and the Peclet numbers of the mobile region varied between 50 and 200. Time moments analysis proved to be a useful tool for quantifying the break through curve (BTC) although the moments were found to be sensitive to experimental scattering in the measured data at larger times. Also, fitted parameters described the experimental data better than moment generated parameter values.

APA, Harvard, Vancouver, ISO, and other styles

Chu, Khim Hoong. "Breakthrough curve analysis by simplistic models of fixed bed adsorption: In defense of the century-old Bohart-Adams model." Chemical Engineering Journal 380 (January 2020): 122513. http://dx.doi.org/10.1016/j.cej.2019.122513.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Wang, Wei, Xiang An Yue, Ren Bao Zhao, and Hui Yang. "Experimental and Theoretical Studies on Effects of Heterogeneity on Channeling in Waterflooding." Advanced Materials Research 518-523 (May 2012): 4084–87. http://dx.doi.org/10.4028/www.scientific.net/amr.518-523.4084.

Full text

Abstract:

Water channeling is easy to occur during the process of water flooding in heterogeneous reservoirs. It leads to injected water noneffective cycling, the recovery decreasing and the development cost rising. By means of physical experiments and theoretical analysis, characteristics of water channeling are studied in different heterogeneous reservoirs. The result shows that when permeability contrast is lesser than 5.88, the development performance of reservoirs is similar to homogeneous reservoirs and water cut rises slowly after water breakthrough. If permeability contrast is higher than 5.88, the recovery curve has an inflexion, water cut rises rapidly and water channeling is easy to occur after breakthrough. Therefore, permeability contrast should be lesser than 5.88 in terms of layer series division in interlayer heterogeneous reservoirs. Measures must be taken to avoid water channeling when permeability contrast is higher than 5.88 in inner heterogeneous reservoirs.

APA, Harvard, Vancouver, ISO, and other styles

Bang, Yeong Hak, Yoon Ho Choi, Mincheol Park, Geon Hee Lee, Soo-yong Shin, and Seok Jin Kim. "Prediction of the breakthrough cancer pain using deep learning model." Journal of Clinical Oncology 39, no. 15_suppl (2021): e24085-e24085. http://dx.doi.org/10.1200/jco.2021.39.15_suppl.e24085.

Full text

Abstract:

e24085 Background: Breakthrough cancer pain (BTcP), a transitory flare of pain that occurs on a background of relatively well-controlled baseline pain, is a challenging clinical problem in managing cancer pain. We hypothesized that the BTcP could be predictable according to the patients’ previous observed patterns. In this study, we report on the development of a deep learning model that predicts hourly individual-level breakthrough pain for patients with cancer. Methods: We defined the BTcP as the pain with numerical rating scale (NRS) score 4 or above and developed models predicting the onset time of BTcP with the temporal resolution of 1 hour. The datasets which have more than 20 records of NRS score during hospitalization were included in our study. All the pain records were obtained from patients hospitalized on the wards of hematology-oncology in Samsung Medical Center between July 2016 to February 2020. The model used the time windows of 3 days to predict NRS scores over the next 24 hours. To capture irregular pain patterns, we created the sequence of average pain patterns over 24 hours from the previous 3 days and used it for normalization. We trained a Bi-directional long-short term memory (LSTM) based deep learning model. The model was validated using the holdout method with 20% of the datasets. Its performance was assessed with the area under the receiver operating characteristic curve (AUROC) and the area under the precision-recall curve (AURPC). Results: We included pain log data containing 2,905 admissions from 2,176 patients with solid cancer and 1,755 admissions from 1,082 patients with hematologic cancer in the analysis. The median age was 57 (interquartile range (IQR), 47-64), the most frequent type of cancer was lung cancer (18.0%), and most patients had stage 4 (60.7%). Among the 103,948 hours from patients in whole datasets, 1,091 (4.7%) hours were labeled as the period of BTcP. The patients have the records of NRS score with a median of 3 (IQR, 2.0-4.5) and BTcP with a median of 1.1 (IQR, 0.5-2.0) per day. We allocated approximately 20% of patients (653 patients with 932 admissions) to the holdout test dataset. Our model showed the AUROC 0.719 and AUPRC 0.680 for predicting the BTcP in the test dataset. Conclusions: Our study showed that cancer pain could be predictive by using a deep learning model. Though our exploratory study has a limitation of generalizability, future warranted subgroup analysis and verification research could make our model more applicable in a real-world setting.

APA, Harvard, Vancouver, ISO, and other styles

Chowdhury, Z. Z., S. M. Zain, A. K. Rashid, R. F. Rafique, and K. Khalid. "Breakthrough Curve Analysis for Column Dynamics Sorption of Mn(II) Ions from Wastewater by UsingMangostana garciniaPeel-Based Granular-Activated Carbon." Journal of Chemistry 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/959761.

Full text

Abstract:

The potential of granular-activated carbon (GAC) derived from agrowaste of Mangostene (Mangostana garcinia) fruit peel was investigated in batch and fixed bed system as a replacement of current expensive methods for treating wastewater contaminated by manganese, Mn(II) cations. Batch equilibrium data was analyzed by Langmuir, Freundlich, and Temkin isotherm models at different temperatures. The effect of inlet metal ion concentration (50 mg/L, 70 mg/L, and 100 mg/L), feed flow rate (1 mL/min and 3 mL/min), and activated carbon bed height (4.5 cm and 3 cm) on the breakthrough characteristics of the fixed bed sorption system were determined. The adsorption data were fitted with well-established column models, namely, Thomas, Yoon-Nelson, and Adams-Bohart. The results were best-fitted with Thomas and Yoon-Nelson models rather than Adams-Bohart model for all conditions. The column had been regenerated and reused consecutively for five cycles. The results demonstrated that the prepared activated carbon was suitable for removal of Mn(II) ions from wastewater using batch as well as fixed bed sorption system.

APA, Harvard, Vancouver, ISO, and other styles

Guo, Leilei, Lin Qian, Mo Xu, et al. "Effect of the loam inter-layer on the migration and breakthrough of benzene under constant flow in the unsaturated zone: column experiments." Water Science and Technology 79, no. 2 (2019): 207–17. http://dx.doi.org/10.2166/wst.2019.003.

Full text

Abstract:

Abstract The reliable prediction of transport and attenuation of dissolved-phase contamination in the unsaturated zone is a complex and multi-process problem. Based on the adsorption properties of soil samples to solutes, the soil column test and laboratory analysis were carried out in this study. The effects of the loam inter-layer on the migration and breakthrough of the characteristic pollutant benzene and non-absorbent Br− were studied. The results showed that the relatively high clay content of the inter-layer significantly changed the BTC (breakthrough curve). It not only delayed the migration time of benzene into the aquifer but also to some extent produced an attenuation effect, effectively reducing the content of the characteristic pollutants through the unsaturated zone. The dispersion coefficient was obtained through the measured Br−. The theoretical values were calculated and compared with the experimental data by using a one-dimensional unsaturated solute transport equation. The result was basically consistent, which proved the validity and reliability of the model. Through the BTC of benzene, the retardation factor was obtained and used to describe the influence of the loam inter-layer on the migration and breakthrough, which could provide the basis for the accurate modeling of groundwater remediation projects.

APA, Harvard, Vancouver, ISO, and other styles

Nakayama, Chieko, and Yoshinori Tanaka. "Adsorption of nitrate as a groundwater pollutant by soil particles." Journal of Nepal Geological Society 34 (October 9, 2006): 141–46. http://dx.doi.org/10.3126/jngs.v34i0.31890.

Full text

Abstract:

This study discusses nitrogen adsorption in several soil samples of the Kanto loam collected from two locations in the Kanto plain. Their chemical properties were assessed on each of the soil samples as well as on pure allophane clay by instrumental analysis using batch and soil column tests. Nitrogen-nitrate adsorption by soil samples was determined by a 10-hour batch test using a nitric acid solution of 0.14 mmol. A saturation column test was conducted to obtain a breakthrough curve and calculate the coefficients of dispersion and retardation. The extent of nitrate adsorption in soil samples was confirmed by percolation with 0.14 mmol nitric acid through columns packed with the soil sample and silicate sand. In the batch test, it was found that the amount of nitrate adsorption was greater in allophane-rich volcanic ash soils with the amount of nitrate adsorption increasing under conditions of low pH. The breakthrough curve determined by the column test showed that the coefficient of retardation increased in allophane-rich soils. Adsorption of nitrates by Kanto loam soils was thus found to be dependent upon the content of allophane and amorphous material in the soil. Since the positive charge of allophane has the potential to reduce the nitrate content in groundwater, it can be effectively applied to reduce nitrate contamination in groundwater.

APA, Harvard, Vancouver, ISO, and other styles

Hanami, Zarah Arwieny, and Puji Lestari. "Characterization and Application of Mangosteen Peel Activated Carbon for Ammonia Gas Removal." Environment and Natural Resources Journal 19, no. 4 (2021): 320–29. http://dx.doi.org/10.32526/ennrj/19/2020298.

Full text

Abstract:

Mangosteen peel can be used as an activated carbon precursor because of its high lignin content and hardness. In this study, mangosteen peel activated carbon (MP-AC) was prepared by a physical activation method using CO2 at 850°C. The Brunauer-Emmett-Teller (BET) analysis was used to assess the optimal activation time to identify the largest surface area. The properties of MP-AC were characterized by the SEM-EDS and FTIR analyses. The results showed that MP-AC obtained from the 120-minute activation time had the largest BET specific surface area of 588.41 m2/g and was selected as an adsorbent in the dynamic adsorption of ammonia gas. The values of moisture content, ash content, and iodine number of MP-AC were 6.07%, 9.8%, and 1153.69 mg/g, respectively. Breakthrough curve indicated that with lower inlet concentration and higher adsorbent mass, longer breakthrough time is reached. Equilibrium data was best fitted to the Langmuir isotherm, while the pseudo-first order kinetic model favorably described the adsorption kinetics. The results revealed a potential to utilize MP-AC as an adsorbent for ammonia gas removal with average NH3 adsorption capacity of 0.41 mg/g.

APA, Harvard, Vancouver, ISO, and other styles

Dolatyari, Leila, Mohammad Reza Yaftian, and Sadegh Rostamnia. "Fixed-bed column dynamic studies and breakthrough curve analysis of Eu(III) ion adsorption onto chemically modified SBA-15 silica materials." Separation Science and Technology 52, no. 3 (2016): 393–403. http://dx.doi.org/10.1080/01496395.2016.1250781.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Hu, Qili, and Zhenya Zhang. "Comment on “Breakthrough curve analysis by simplistic models of fixed bed adsorption: In defense of the century-old Bohart–Adams model”." Chemical Engineering Journal 394 (August 2020): 124511. http://dx.doi.org/10.1016/j.cej.2020.124511.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Bahrun, Mohd Hardyianto Vai, Awang Bono, Nur Kamaliyah Dzilrazman, and Zykamilia Kamin. "Recovery of Minor Palm Oil Compounds Using Packed Bed Adsorption Column." Jurnal Bahan Alam Terbarukan 9, no. 1 (2020): 21–29. http://dx.doi.org/10.15294/jbat.v9i1.23461.

Full text

Abstract:

Carotene and tocopherol are valuable products that exist as minor compounds in palm oil and mostly extracted out during many stages of palm oil processing. Hence, most of it ended up in wastewater or palm oil mill effluent (POME). Fortunately, adsorption is potentially one of the most efficient method as compared to the others. In fact, it is widely studied in laboratory scale, in order to obtain equilibrium data for the steady state system. However, industrial practices are mostly operated in unsteady state in a continuous manner. Consequently, this study is executed to design a recovery process of one of the minor compounds in palm oil mill effluent (POME), which is carotene, using silica gel. It aims to predict the dynamic adsorption of recovery of minor compounds from palm oil mill effluent based on available equilibrium data, investigate the effects of dynamic and physical properties of the system towards the process by analyzing the breakthrough curve and study the feasibility of the scale up process by performing a sensitivity analysis on the system. Then, a base simulation was prepared by using available equilibrium data. Operating and design parameters such as, bed height, inlet flowrate and concentration were manipulated. Consistent with previous packed column studies, increase flow and concentration will reduce the time required for the column to achieve saturation, while increase bed height effects were vice versa. Finally, the last objective to achieve was to study the practicality of the packed bed column and perform a sensitivity on assumptions and predictions such as predicted mass transfer coefficient and isotherm model. It is proven that the selection of isotherm model and prediction in coefficient did not pose a large impact to the breakthrough curve and the average time required for the column of 1.5 m tall and 0.8 in diameter, to reach breakthrough time is 1.7 days. Hence, it can be concluded that adsorption technology using silica gel as its adsorbent can be applied is recovering minor compounds in palm oil mills.

APA, Harvard, Vancouver, ISO, and other styles

Zhang, Jihuan. "Environmental Kuznets Curve Hypothesis on CO2 Emissions: Evidence for China." Journal of Risk and Financial Management 14, no. 3 (2021): 93. http://dx.doi.org/10.3390/jrfm14030093.

Full text

Abstract:

China is the largest CO2 emitter in the world, and it shared 28% of the global CO2 emissions in 2017. According to the Paris Agreement, it is estimated that China’s CO2 emissions will reach its peak by 2030. However, whether or not the CO2 emissions in China will rise again from its peak is still unknown. If the emission level continues to increase, the Chinese policymakers might have to introduce a severe CO2 reduction policy. The aim of this paper is to conduct an empirical analysis on the long-standing relationship between CO2 emissions and income while controlling energy consumption, trade openness, and urbanization. The autoregressive distributed lag (ARDL) model and the bounds test were adopted in evaluating the validity of the Environmental Kuznets Curve (EKC) hypothesis. The quantile regression was also used as an inference approach. The study reveals two major findings: first, instead of the conventional U-shaped EKC hypothesis, there is the N-shaped relationship between CO2 emissions and real gross domestic product (GDP) per capita in the long run. Second, a positive effect of energy consumption and a negative effect of urbanization on CO2 emissions, in the long run, are also estimated. Quantitatively, if energy consumption rises by 1%, then CO2 emissions will increase by 0.9% in the long run. Therefore, the findings suggest that a breakthrough, in terms of policymaking and energy innovation under China’s specific socioeconomic and political circumstances, are required for future decades.

APA, Harvard, Vancouver, ISO, and other styles

Bodin, Jacques. "MFIT 1.0.0: Multi-Flow Inversion of Tracer breakthrough curves in fractured and karst aquifers." Geoscientific Model Development 13, no. 6 (2020): 2905–24. http://dx.doi.org/10.5194/gmd-13-2905-2020.

Full text

Abstract:

Abstract. More than half of the Earth's population depends largely or entirely on fractured or karst aquifers for their drinking water supply. Both the characterization and modeling of these groundwater reservoirs are therefore of worldwide concern. Artificial tracer testing is a widely used method for the characterization of solute (including contaminant) transport in groundwater. Tracer experiments consist of a two-step procedure: (1) introducing a conservative tracer-labeled solution into an aquifer, usually through a sinkhole or a well, and (2) measuring the concentration breakthrough curve (BTC) response(s) at one or several downstream monitoring locations, usually spring(s) or pumping well(s). However, the modeling and interpretation of tracer test responses can be a challenging task in some cases, notably when the BTCs exhibit multiple local peaks and/or extensive backward tailing. MFIT (Multi-Flow Inversion of Tracer breakthrough curves) is a new open-source Windows-based computer package for the analytical modeling of tracer BTCs. This software integrates four transport models that are all capable of simulating single- or multiple-peak and/or heavy-tailed BTCs. The four transport models are encapsulated in a general multiflow modeling framework, which assumes that the spatial heterogeneity of an aquifer can be approximated by a combination of independent one-dimensional channels. Two of the MFIT transport models are believed to be new, as they combine the multiflow approach and the double-porosity concept, which is applied at the scale of the individual channels. Another salient feature of MFIT is its compatibility and interface with the advanced optimization tools of the PEST suite of programs. Hence, MFIT is the first BTC fitting tool that allows for regularized inversion and nonlinear analysis of the postcalibration uncertainty of model parameters.

APA, Harvard, Vancouver, ISO, and other styles

Li, Kenli, Shuting Zou, and Jin Xv. "Fast Parallel Molecular Algorithms for DNA-Based Computation: Solving the Elliptic Curve Discrete Logarithm Problem overGF(2n)." Journal of Biomedicine and Biotechnology 2008 (2008): 1–10. http://dx.doi.org/10.1155/2008/518093.

Full text

Abstract:

Elliptic curve cryptographic algorithms convert input data to unrecognizable encryption and the unrecognizable data back again into its original decrypted form. The security of this form of encryption hinges on the enormous difficulty that is required to solve the elliptic curve discrete logarithm problem (ECDLP), especially overGF(2n),n∈Z+. This paper describes an effective method to find solutions to the ECDLP by means of a molecular computer. We propose that this research accomplishment would represent a breakthrough for applied biological computation and this paper demonstrates that in principle this is possible. Three DNA-based algorithms: a parallel adder, a parallel multiplier, and a parallel inverse overGF(2n)are described. The biological operation time of all of these algorithms is polynomial with respect ton. Considering this analysis, cryptography using a public key might be less secure. In this respect, a principal contribution of this paper is to provide enhanced evidence of the potential of molecular computing to tackle such ambitious computations.

APA, Harvard, Vancouver, ISO, and other styles

Wen, T., X. Zhang, H. Q. Zhang, and J. D. Liu. "Ammonium removal from aqueous solutions by zeolite adsorption together with chemical precipitation." Water Science and Technology 61, no. 8 (2010): 1941–47. http://dx.doi.org/10.2166/wst.2010.145.

Full text

Abstract:

The aim of this study was to remove ammonium from aqueous solution and recycle ammonium. Ammonium removal from aqueous solution by natural and pretreated zeolites, breakthrough curve, chemical regeneration of pretreated zeolite, ammonium removal from regeneration solution by chemical precipitation and NH4+ adsorption isotherms were investigated by conducting a series of batch and continuous experiments in this study. Morphologies and structures of zeolites were analyzed by Surface Area and Pore Size analysis, Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR) spectroscopy. The NH4+-N removal efficiencies by natural and NaCl-treated zeolite were 30.73% and 85.55% respectively at an initial concentration of 100 mg/L. Breakthrough and exhaustion capacities for adsorption of ammonium ions were 3.36 and 4.26 mg /g (NH4+-N/zeolite), respectively. After chemical regeneration, NH4+-N removal efficiency by NaCl-treated zeolite only reduced 9.95% than previously. NH4+-N concentration of the regeneration solution was reduced from 460 to 74.55 mg/L by chemical precipitation. The Freundlich isotherm provided a slightly more consistent fit to the experimental data of ammonium adsorption on NaCl-treated zeolite than Langmuir. Based on the results, it was concluded that the objective of this study had been well achieved.

APA, Harvard, Vancouver, ISO, and other styles

Aziz, Abdul Shukor Abdul, Latifah Abd Manaf, Hasfalina Che Man, and Nadavala Siva Kumar. "Column dynamic studies and breakthrough curve analysis for Cd(II) and Cu(II) ions adsorption onto palm oil boiler mill fly ash (POFA)." Environmental Science and Pollution Research 21, no. 13 (2014): 7996–8005. http://dx.doi.org/10.1007/s11356-014-2739-5.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Chu, Khim Hoong. "Rebuttal to comment on “Breakthrough curve analysis by simplistic models of fixed bed adsorption: in defense of the century-old Bohart-Adams model”." Chemical Engineering Journal 398 (October 2020): 125546. http://dx.doi.org/10.1016/j.cej.2020.125546.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Recepoğlu, Yaşar K., Nalan Kabay, Idil Yılmaz Ipek, et al. "Packed bed column dynamic study for boron removal from geothermal brine by a chelating fiber and breakthrough curve analysis by using mathematical models." Desalination 437 (July 2018): 1–6. http://dx.doi.org/10.1016/j.desal.2018.02.022.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Gîlcă, Emilia, Andrada Măicăneanu, and Petru Ilea. "Kinetics analysis of zinc sorption in fixed bed column using a strongly basic anionic exchange resin." Water Science and Technology 71, no. 11 (2015): 1646–53. http://dx.doi.org/10.2166/wst.2015.136.

Full text

Abstract:

The aim of this study was to examine the capacity of anionic resins to remove zinc as zinc chloride complexes in fixed bed. The applicability of the kinetics models and the characteristics of the bed (sorption capacity, breakthrough curve, depth of the adsorption zone) were taken into account. The influence of the process parameters, such as resin quantity (bed height) and zinc initial concentration, on the removal process was also considered. The obtained results (Amberlite IRA410) were analyzed using sorption kinetic models such as Thomas, Adam-Bohart, and Clark, by linear regression analysis. Similarly, the concept of the mass transfer zone was applied in order to properly design the fixed bed adsorption process. By comparing various resins, the following series was depicted based on sorption capacities: Amberlite IRA410 &gt; Purolite A103S &gt; Purolite NRW700 &gt; Purolite A400MBOH. The experimental data were in good agreement with the Clark model, while for the other models, lower correlation coefficients were obtained under the same experimental conditions. The MTZ height and rate of movement increased with increasing initial concentration.

APA, Harvard, Vancouver, ISO, and other styles

Guo, Qiehui, Zhongyang Zang, Jie Ma, Jingyi Li, Tong Zhou, and Runping Han. "Adsorption of copper ions from solution using xanthate wheat straw." Water Science and Technology 82, no. 10 (2020): 2029–38. http://dx.doi.org/10.2166/wst.2020.487.

Full text

Abstract:

Abstract To enhance adsorption capacity of wheat straw (WS) toward copper ion from solution, carbon disulfide was used to modify WS by a facile grafting method through epichlorohydrin and ethylenediamine. So WS containing xanthate groups (XWS) was obtained. The XWS was characterized using elemental analysis, X-ray diffraction, infrared spectroscopy and adsorption property of XWS toward copper ions. The results showed that S was introduced into the surface of WS. The solution pH was in favor of Cu2+ adsorption at pH 5, while NaCl existing in solution was slightly favorable for adsorption. The adsorption kinetic followed the pseudo-second-order kinetic model, while the adsorption isotherm curve was well fitted using the Langmuir model. The adsorption capacity was 57.5 mg·g−1 from experiment. The process was entropy-produced, endothermic and spontaneous in nature. The column adsorption was performed and Yan model was good to predict the breakthrough curve. XWS as adsorbent is promising to remove copper ions from solution, and this offers one way of effective utilization of waste byproduct from agriculture.

APA, Harvard, Vancouver, ISO, and other styles

Lim, Jun Hyun, Yong Seop Han, Sang Joon Lee, and Ki Yup Nam. "Risk factors for breakthrough vitreous hemorrhage after intravitreal tissue plasminogen activator and gas injection for submacular hemorrhage associated with age related macular degeneration." PLOS ONE 15, no. 12 (2020): e0243201. http://dx.doi.org/10.1371/journal.pone.0243201.

Full text

Abstract:

Purpose We investigated risk factors for breakthrough vitreous hemorrhage (VH) after an intravitreal tissue plasminogen activator (tPA) and gas injection in patients with submacular hemorrhage (SMH) associated with age-related macular degeneration (AMD). Methods The medical records of patients diagnosed with SMH associated with AMD who received an intravitreal tPA (50 μg/0.05 mL) and perfluoropropane gas (0.3 mL) injection were reviewed retrospectively. We analyzed the associations of breakthrough VH with age, sex, best-corrected visual acuity, intraocular pressure, AMD subtype, accompanying sub-retinal pigment epithelium (RPE) hemorrhage, history of cataract surgery, history of hypertension and diabetes mellitus, history of drinking and smoking, and history of antiplatelet or anticoagulant medication. We also examined the relationships between various parameters, including the area ratio of the SMH to the optic disc (AHD) and the height of the SMH obtained from optical coherence tomography. Results In total, 52 eyes from 52 patients were enrolled in this study; 16 eyes (30%) showed breakthrough VH. The proportions of patients with a current smoking history were 75.0% in the VH group and 22.2% in the non-VH group (p = 0.010). Other factors did not differ significantly between the two groups. The proportion of cases with accompanying sub-RPE hemorrhage was 50.0% and 58.3% in the VH and non-VH groups, respectively (p = 0.763). The AHD (p = 0.001) and SMH height (p < 0.001) were significantly greater in the VH group. In a receiver operating characteristic curve analysis, the cut-off values of AHD and SMH height were 20.1 and 1208 μm, respectively. According to logistic regression analysis, when the AHD and SMH height were greater than the individual cut-off values, the odds ratio of VH increased by 10.286 fold (95% confidence interval [CI], 2.452–43.148; p = 0.001) and 75.400 fold (95% CI, 7.991–711.441; p < 0.001), respectively, with respect to their respective reference groups (less than the cut-off value). Among the significant factors associated with VH occurrence, including current smoking, AHD, and SMH height, only current smoking and SMH height were found to be significant in multiple regression analysis (p = 0.040, 0.016). Conclusions The incidence of breakthrough VH was significantly higher in those with current smoking status and for SMH with a larger AHD and greater height. The height of the SMH was more predictable of the possibility of VH than AHD.

APA, Harvard, Vancouver, ISO, and other styles

Punatar, Sachin, Lingaraj Nayak, Avinash Bonda, et al. "Ratio of total leukocyte count to C-reactive protein: does it help to differentiate infectious fever from engraftment fever in patients undergoing autologous hematopoietic stem cell transplant?" Cellular Therapy and Transplantation 9, no. 2 (2020): 40–46. http://dx.doi.org/10.18620/ctt-1866-8836-2020-9-2-40-46.

Full text

Abstract:

Engraftment fever (EF) is a common complication of autologous HSCT (AHSCT). It is difficult to discern it from infectious fever (IF). We studied the significance of total blood leucocyte count (TLC) to C-reactive protein (CRP) ratio in differentiating EF from IF. 109 consecutive AHSCT patients were retrospectively analysed between March 2011 and August 2013. Breakthrough fever (BF) was defined as new-onset fever preceded by an afebrile period of at least 48 hours. The BF episodes were classified as IF or EF. Infectious fever was diagnosed in case of blood culture positivity, radiological signs of infection, or fever subsiding within 48 hours of changing the antibiotics. Engraftment fever was defined in cases associated with rising leucocyte counts without identifiable infective focus. EF responded well to steroid therapy. Daily TLC and CRP values were obtained from patients’ records. Optimal cut-off value of ratio on day of BF was obtained by plotting ROC curve. Sensitivity and specificity were calculated at this value. Among 109 cases, the breakthrough fever manifested in seventy patients. The median term for BF was day +9. Sixty-two patients had the EF. Median value of TLC/CRP ratio on the day of BF was significantly higher in patients with EF than with IF (0.139 vs 0.038, p=0.013). With ROC analysis, the AUC value was 0.78 (95%CI – 0.66-0.89, p<0.0001). The ROC curve provided the optimal TLC/CRP value of 0.056. Using a ratio >0.056 for EF, the sensitivity and specificity were 63% (95%CI 50-75%) and 100% (95%CI 63-100%) respectively. TLC/CRP ratio >0.056 is highly specific for EF. Prospective studies are warranted to confirm these findings.

APA, Harvard, Vancouver, ISO, and other styles

Schmid, Bernhard H., Michael A. Hengl, and Ursula Stephan. "Salt tracer experiments in constructed wetland ponds with emergent vegetation: laboratory study on the formation of density layers and its influence on breakthrough curve analysis." Water Research 38, no. 8 (2004): 2095–102. http://dx.doi.org/10.1016/j.watres.2004.01.038.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Yasui, Shinji, Tadashi Shojo, Goichi Inoue, Kunihiko Koike, Akihiro Takeuchi, and Yoshio Iwasa. "Gas-Solid Reaction Properties of Fluorine Compounds and Solid Adsorbents for Off-Gas Treatment from Semiconductor Facility." International Journal of Chemical Engineering 2012 (2012): 1–9. http://dx.doi.org/10.1155/2012/329419.

Full text

Abstract:

We have been developing a new dry-type off-gas treatment system for recycling fluorine from perfluoro compounds present in off-gases from the semiconductor industry. The feature of this system is to adsorb the fluorine compounds in the exhaust gases from the decomposition furnace by using two types of solid adsorbents: the calcium carbonate in the upper layer adsorbs HF and converts it to CaF2, and the sodium bicarbonate in the lower layer adsorbs HF and SiF4and converts them to Na2SiF6. This paper describes the fluorine compound adsorption properties of both the solid adsorbents—calcium carbonate and the sodium compound—for the optimal design of the fixation furnace. An analysis of the gas-solid reaction rate was performed from the experimental results of the breakthrough curve by using a fixed-bed reaction model, and the reaction rate constants and adsorption capacity were obtained for achieving an optimal process design.

APA, Harvard, Vancouver, ISO, and other styles

Askari, Mahdi, Ehsan Salehi, Mohammad Ebrahimi, and Aboulfazl Barati. "Application of breakthrough curve analysis and response surface methodology for optimization of a hybrid separation system consisting of fixed-bed column adsorption and dead-end depth filtration." Chemical Engineering and Processing - Process Intensification 143 (September 2019): 107594. http://dx.doi.org/10.1016/j.cep.2019.107594.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Manikrishna*, K. S. G. V., Veluru Sridevi, Sri Himaja Pamu, M. Tukaram Bai, and K. S. NV Prasad. "Biosorption of Malachite Green Dye from Wastewater with Henfeathers -Analysis of Various Mathematical Models Wrt Continuous Adsorption." International Journal of Innovative Technology and Exploring Engineering 10, no. 10 (2021): 15–23. http://dx.doi.org/10.35940/ijitee.j9387.08101021.

Full text

Abstract:

In recent years, the remediation of hazardous organic dye-contaminated aquatic habitats has been a key research priority for environmental and chemical engineers. The goal of this research was to see how well malachite green adsorbs from waste water in a continuous column system having fixed bed. A biosorbent made from waste materials such as hen feathers has been shown to extract the water-soluble malachite green colour from waste water. The adsorption potential of malachite green dye ions in a continuous flow adsorption column is investigated in this work. The hen feathers' performance in the fixed bed column was assessed under a variety of operating circumstances, including bed height in the range 6-10cm; flow in the range 4-12ml/min, and starting concentration (10-30 mg/l). In comparison to other testing settings, the bed height (8cm), flowrate (12ml/min), and maximum input concentration (20mg/l) resulted in the highest malachite green absorption of 2.829mg/g. The column experimental data collected under various conditions was evaluated using three distinct models namely 1. Bohart-Adams model, 2 Yoon-Nelsons model, and 3 BDST model, all of which produced a decent estimation of the breakthrough curve. The findings from the Yoon-nelson and BDST models, on the other hand, were more favourable. The several characteristics of the hen feathers were studied using FTIR studies. The activated hen feather powder was a successful potential bio sorbent for the malachite green from aqueous phase.

APA, Harvard, Vancouver, ISO, and other styles

Ilk, Noyan, Guangzhi Shang, Shaokun Fan, and J. Leon Zhao. "Stability of Transaction Fees in Bitcoin: A Supply and Demand Perspective." MIS Quarterly 45, no. 2 (2021): 563–692. http://dx.doi.org/10.25300/misq/2021/15718.

Full text

Abstract:

Cryptocurrencies such as Bitcoin are breakthrough financial technologies that promise to revolutionize the digital economy. Unfortunately, their long-term adoption in the business world is imperiled by a lack of stability that manifests as dramatic swings in transaction fees and severe participant dissatisfaction. To date, there has been little academic effort to study how system participants react to volatility in fee movements. Our study addresses this research gap by conceptualizing the Bitcoin platform as a data space market and studying how market equilibrium forms between users who demand data space while trying to avoid transaction delays, and miners who supply data space while trying to maximize fee revenues. Our empirical analysis based on past bitcoin transactions reveals the existence of a relatively flat downward-sloping demand curve and a much steeper upward-sloping supply curve. Regarding users, the inelastic nature of demand signals the utility of Bitcoin as a niche platform for transactions that are otherwise difficult to conduct. This result challenges the belief that users may easily abandon Bitcoin technology given rising transaction costs. We also find that the use of bitcoins as a trading asset is associated with higher levels of tolerance to fees. Regarding miners, the comparatively elastic nature of supply indicates that higher fees stimulate mining by a larger magnitude than suppressing demand. This finding implies that, ceteris paribus, the Bitcoin system turns to self-regulate transaction fees in an efficient manner. Our work has implications for the management of congestion in blockchain-based systems and more broadly for the stability of cryptocurrency markets.

APA, Harvard, Vancouver, ISO, and other styles

Sugashini, S., and K. M. Meera Sheriffa Begum. "Column Adsorption Studies for the Removal of Cr(VI) Ions by Ethylamine Modified Chitosan Carbonized Rice Husk Composite Beads with Modelling and Optimization." Journal of Chemistry 2013 (2013): 1–11. http://dx.doi.org/10.1155/2013/460971.

Full text

Abstract:

The objective of this present study is the optimization of process parameters in adsorption of Cr(VI) ions by ethylamine modified chitosan carbonized rice husk composite beads (EAM-CCRCBs) using response surface methodology (RSM) and continuous adsorption studies of Cr(VI) ions by ethylamine modified chitosan carbonized rice husk composite beads (EAM-CCRCBs). The effect of process variables such as initial metal ion concentration, adsorbent dosage and pH were optimized using RSM in order to ensure high adsorption capacity at low adsorbent dosage and high initial metal ion concentration of Cr(VI) in batch process. The optimum condition suggested by the model for the process variable such as adsorbent dosage, pH and initial metal ion concentration was 0.14 g, 300 mg/L and pH2 with maximum removal of 99.8% and adsorption capacity of 52.7 mg/g respectively. Continuous adsorption studies were conducted under optimized initial metal ion concentration and pH for the removal of Cr(VI) ions using EAM-CCRCBs. The breakthrough curve analysis was determined using the experimental data obtained from the continuous adsorption. Continuous adsorption modelling such as bed depth service model and Thomson model were established by fitting it with experimental data.

APA, Harvard, Vancouver, ISO, and other styles

Lu, Feng Lai, Jin Lei Liu, Dian Peng Li, Jian Zhang Wu, Yue Yuan Chen, and Yong Xin Wen. "Quantification and Enrichment of Esculeoside a from Fresh Tomato Fruits." Advanced Materials Research 396-398 (November 2011): 556–64. http://dx.doi.org/10.4028/www.scientific.net/amr.396-398.556.

Full text

Abstract:

Esculeoside A, the tomato saponins from Lycopersicon esculentum MILL, may be metabolized into various steroidal hormones such as pregnane derivatives that are expected to exhibit various bioactivities in the body, such as anti-osteoporosis, antimenopausal disorder and anti-tumor actions. In order to enrich large amount of esculeoside A for further scientific research, we firstly developed a high performance liquid chromatography (HPLC) with evaporative light scattering detection (ELSD) method for its quantification, and used it to examined the content of esculeoside A in different cultivated varieties of tomato fruits and tomato extract. Statistical analysis of the obtained data demonstrated that our method was simple, and has achieved desired linearity, precision and accuracy. Then we have explored the feasibility of using pectinase as a means for assisting esculeoside A extraction from fresh tomato fruits, and several factors such as the enzyme concentration, pH value of enzyme solution, temperature, incubation time which influenced on extraction were investigated. Moreover, in our previous study, the adsorption characteristics on several types of macroporous resins have been compared. Among them, D-101 resin showed the best separation behaviors on esculeoside A. So in the present paper, in order to get the best parameters for D101 adsorption, the adsorption kinetic curve, the appropriate ethanol concentration for elution and breakthrough volume were analyzed．

APA, Harvard, Vancouver, ISO, and other styles

Herrero-Huerta, M., V. Meline, A. S. Iyer-Pascuzzi, A. M. Souza, M. R. Tuinstra, and Y. Yang. "ROOT PHENOTYPING FROM X-RAY COMPUTED TOMOGRAPHY: SKELETON EXTRACTION." International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B4-2021 (June 30, 2021): 417–22. http://dx.doi.org/10.5194/isprs-archives-xliii-b4-2021-417-2021.

Full text

Abstract:

Abstract. Breakthrough imaging technologies are a potential solution to the plant phenotyping bottleneck in marker-assisted breeding and genetic mapping. X-Ray CT (computed tomography) technology is able to acquire the digital twin of root system architecture (RSA), however, advances in computational methods to digitally model spatial disposition of root system networks are urgently required.We extracted the root skeleton of the digital twin based on 3D data from X-ray CT, which is optimized for high-throughput and robust results. Significant root architectural traits such as number, length, growth angle, elongation rate and branching map can be easily extracted from the skeleton. The curve-skeleton extraction is computed based on a constrained Laplacian smoothing algorithm. This skeletal structure drives the registration procedure in temporal series. The experiment was carried out at the Ag Alumni Seed Phenotyping Facility (AAPF) at Purdue University in West Lafayette (IN, USA). Three samples of tomato root at 2 different times and three samples of corn root at 3 different times were scanned. The skeleton is able to accurately match the shape of the RSA based on a visual inspection.The results based on a visual inspection confirm the feasibility of the proposed methodology, providing scalability to a comprehensive analysis to high throughput root phenotyping.

APA, Harvard, Vancouver, ISO, and other styles

Gaujoux, Renaud, Elina Starosvetsky, Naama Maimon та ін. "Cell-centred meta-analysis reveals baseline predictors of anti-TNFα non-response in biopsy and blood of patients with IBD". Gut 68, № 4 (2018): 604–14. http://dx.doi.org/10.1136/gutjnl-2017-315494.

Full text

Abstract:

ObjectiveAlthough anti-tumour necrosis factor alpha (anti-TNFα) therapies represent a major breakthrough in IBD therapy, their cost–benefit ratio is hampered by an overall 30% non-response rate, adverse side effects and high costs. Thus, finding predictive biomarkers of non-response prior to commencing anti-TNFα therapy is of high value.DesignWe analysed publicly available whole-genome expression profiles of colon biopsies obtained from multiple cohorts of patients with IBD using a combined computational deconvolution—meta-analysis paradigm which allows to estimate immune cell contribution to the measured expression and capture differential regulatory programmes otherwise masked due to variation in cellular composition. Insights from this in silico approach were experimentally validated in biopsies and blood samples of three independent test cohorts.ResultsWe found the proportion of plasma cells as a robust pretreatment biomarker of non-response to therapy, which we validated in two independent cohorts of immune-stained colon biopsies, where a plasma cellular score from inflamed biopsies was predictive of non-response with an area under the curve (AUC) of 82%. Meta-analysis of the cell proportion-adjusted gene expression data suggested that an increase in inflammatory macrophages in anti-TNFα non-responding individuals is associated with the upregulation of the triggering receptor expressed on myeloid cells 1 (TREM-1) and chemokine receptor type 2 (CCR2)-chemokine ligand 7 (CCL7) –axes. Blood gene expression analysis of an independent cohort, identified TREM-1 downregulation in non-responders at baseline, which was predictive of response with an AUC of 94%.ConclusionsOur study proposes two clinically feasible assays, one in biopsy and one in blood, for predicting non-response to anti-TNFα therapy prior to initiation of treatment. Moreover, it suggests that mechanism-driven novel drugs for non-responders should be developed.

APA, Harvard, Vancouver, ISO, and other styles

Grindrod, Peter, Mark S. Edwards, Jenny J. W. Higgo, and Geoffrey M. Williams. "Analysis of colloid and tracer breakthrough curves." Journal of Contaminant Hydrology 21, no. 1-4 (1996): 243–53. http://dx.doi.org/10.1016/0169-7722(95)00051-8.

Full text

APA, Harvard, Vancouver, ISO, and other styles

puii, Lalchhing, Seung-Mok Lee, and Diwakar Tiwari. "Synthesis and Characterization of Chitosan templated Mesoporous Silica: Efficient use of Mesoporous Silica in the removal of Cu(II) from Aqueous Solutions." Science & Technology Journal 4, no. 2 (2016): 105–12. http://dx.doi.org/10.22232/stj.2016.04.02.04.

Full text

Abstract:

A mesoporous silica was synthesized by annealing (3-Aminopropyl) triethoxysilane grafted chitosan at 800˚C. The mesoporous silica was characterized by the XRD (X-ray diffraction) analysis. The BET specific surface area and pore size of silica was found to be 178.42 m2/g and 4.13 nm. The mesoporous silica was then employed for the efficient remediation of aqueous solutions contaminated with Cu(II) under batch and column reactor operations. The mesoporous silica showed extremely high per cent removal of Cu(II) at wide pH range i.e., pH ~2.0 to 7.0. Relatively a fast uptake of Cu(II) was occurred and high percentage removal was obtained at initial concentrations studied from 1.0 to 15.0 mg/L. The equilibrium state sorption data were utilized for the Langmuir and Freundlich adsorption isotherm studies. Moreover, the effect of an increase in background electrolyte concentrations from 0.0001 to 0.1 mol/L NaNO3 was assessed for the uptake of Cu(II) by mesoporous silica. The equilibrium sorption was achieved within 240 min of contact and the kinetic data is best fitted to the pseudo-second-order and fractal like pseudo-second-order kinetic models. In addition, the mesoporous silica was used for dynamic studies under column reactor operations. The breakthrough curve was then used for the non-linear fitting of the Thomas equation and the loading capacity of the column for Cu(II) was estimated.

APA, Harvard, Vancouver, ISO, and other styles

Coronado, M., J. Ramírez Sabag, O. Valdiviezo Mijangos, and C. Somaruga. "A test of the effect of boundary conditions on the use of tracers in reservoir characterization." Geofísica Internacional 48, no. 2 (2009): 185–94. http://dx.doi.org/10.22201/igeof.00167169p.2009.48.2.2136.

Full text

Abstract:

   Tracer tests are fundamental in characterizing fluid flow in underground formations. However, the setting of appropriate boundary conditions in even simple analytical models has historically been controversial, mainly due to the lack of sufficient physical evidence. Determining the relevance of boundary conditions on tracer test analysis becomes therefore a topic of renewed interest. The subject has been previously disscused by studying the tracer breakthrough curve sensitivity to diverse model parameter values. In our present work we examine the issue from a new practical reservoir characterization perspective. Two well-known equivalent elementary tracer transport models having different boundary conditions are matched to the same tracer test data. The resulting model parameter difference quantifies the effect of boundary conditions on reservoir property determination. In our case a tracer pulse injected in a homogeneous one-dimensional porous medium and moving at constant speed dominated by advection and dispersion is considered. The tracer transport models to be used yield conditions (i) on the tracer concentration, and (ii) on the tracer flux. Three data sets from tracer tests performed in different oil reservoirs are used to fit the models and determine the parameter values. We found that boundary conditionsbecome more important as Peclet number gets smaller. The cases analyzed have Peclet numbers 25.0, 5.4 and 3.7. The largest parameter difference obtained in each case is 5%, 18% and 37% respectively. These differences are large for laboratory experiments, but less relevant for tracer tests in oil fields, where data variability is frequently high. Nevertheless, attention should be paid when small Peclet numbers are present.  

APA, Harvard, Vancouver, ISO, and other styles

Rudenko, Hannah C., Vasantha Brito-Babapulle, David Gonzalez, et al. "Combined aCGH and Mutational Analysis of CLL Patients with 17p Deletion." Blood 108, no. 11 (2006): 2091. http://dx.doi.org/10.1182/blood.v108.11.2091.2091.

Full text

Abstract:

Abstract We have utilised aCGH (Breakthrough Breast Cancer Research Centre 5.8K array) and mutational analysis of the TP53 gene (exons 4–10) on 74 cases of CLL to define the extent of deletion at 17p, TP53 mutational status, additional genomic changes, and how this affects clinical outcome. 17p- cases were selected by FISH (n=37, Vysis LSI P53 probe) and 37 cases were selected as being representative of the survival curve of CLL patients without 17p-. FISH identified 22 cases with TP53- in ≥ 50% of cells, 4 cases with TP53- 20–50% and 11 cases with TP53- ≤ 20%. aCGH can detect abnormalities present in >50% of cells and all of the TP53- cases greater than 50% by FISH were detected with deletion ranging between 6-20Mb in length, the majority encompassing the entire p-arm. In addition aCGH detected deletion of 17p in 5/15 cases with TP53- <50%, and 2/37 with no detectable TP53- by FISH, these deletions clustered at 17p13.3 and 17p11.2, and did not involve the TP53 gene. Cases with 17p- >20% have a poor clinical outcome (median survival 11 months, median progression free survival 3 months), the majority of these (85%) also have a mutation of TP53 whereas in cases with ≤ 20% 17p- only 10% were mutated. The 17p- group was characterised by additional recurrent deletions involving 18p, 20p and 22q, which tended to occur as single additional events. Understanding the order in which these events occur is important, 18p- was found in 6 cases, 2 of which had <50% 17p- by FISH, suggesting that 18p- is present in a higher percentage of cells and by implication occurs prior to the 17p deletion, a similar finding was also present for the 20p- cases. 18p deletion varied in length between 5.9Mb and 12Mb, with the minimally deleted region (MDR) involving a 2.5Mb region spanning 18p11.23-p11.22. 20p- was found in 8 cases of which 3 covered almost the entire p-arm, and 5 formed 2 clusters at each end of the p-arm. 22q- was found in 8 cases, with only 1 outside of the 17p- group. Out of these 8 cases with deletion, 6 covered almost the complete q-arm but a MDR was difficult to define, however if the non-17p- case is excluded the MDR covers 1.4Mb at 22q12.3. Recurrent abnormalities were also found on other chromosomes, but did not differ between the two groups. These included regions with previously identified abnormalities; trisomy 12 (n=11), loss of 6q14.1–24.3 (n=11), loss of 11q12.1–25 (n=17) and loss of 13q12.1–21.1 (n=6) as well as detection of novel abnormalities; gain of 4p16.3–16.1 (n=23), gain of 11p15.5–15.3 (n=22), gain of 22q11.21–13.33 (n=22) and deletions on chromosome 9 (n=9). These results show that deletion of TP53 and mutation of the other allele are critical adverse prognostic factors. We have also defined a genetic background (18p-, 20p- and 22q-) on which these changes arise.

APA, Harvard, Vancouver, ISO, and other styles

Mathias, S. A., A. P. Butler, T. C. Atkinson, S. Kachi, and R. S. Ward. "A parameter identifiability study of two chalk tracer tests." Hydrology and Earth System Sciences Discussions 3, no. 4 (2006): 2437–71. http://dx.doi.org/10.5194/hessd-3-2437-2006.

Full text

Abstract:

Abstract. As with most fractured rock formations, Chalk is highly heterogeneous. Therefore, meaningful estimates of model parameters must be obtained at a scale comparable with the process of concern. These are frequently obtained by calibrating an appropriate model to observed concentration-time data from radially convergent tracer tests (RCTT). Arguably, an appropriate model should consider radially convergent dispersion (RCD) and Fickian matrix diffusion. Such a model requires the estimation of at least four parameters. A question arises as to whether or not this level of model complexity is supported by the information contained within the calibration data. Generally modellers have not answered this question due to the calibration techniques employed. A dual-porosity model with RCD was calibrated to two tracer test datasets from different UK Chalk aquifers. A multivariate sensitivity analysis, which assumed only a priori upper and lower bounds for each model parameter, was undertaken. Rather than looking at measures of uncertainty, the shape of the multivariate objective function surface was used to determine whether a parameter was identifiable. Non-identifiable parameters were then removed and the procedure was repeated until all remaining parameters were identifiable. It was found that the single fracture model (SFM) (which ignores mechanical dispersion) obtained the best mass recovery, excellent model performance and best parameter identifiability in both the tests studied. However, there was no objective evidence suggesting that mechanical dispersion was negligible. Moreover, the SFM (with just two parameters) was found to be good at approximating the Single Fracture Dispersion Model SFDM (with three parameters) when different, and potentially erroneous parameters, were used. Overall, this study emphasises the importance of adequate temporal sampling of breakthrough curve data prior to peak concentrations, to ensure adequate characterisation of mechanical dispersion processes, and continued monitoring afterwards, to ensure adequate characterisation of fracture spacing (where possible), when parameterising dual-porosity solute transport models.

APA, Harvard, Vancouver, ISO, and other styles

We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!