Relevant bibliographies by topics / Acidity

Academic literature on the topic 'Acidity'

Author: Grafiati
Published: 4 June 2021
Last updated: 25 May 2024

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Journal articles on the topic "Acidity"

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Zhang, Wen Lin, Wei Du, Xiao Wen Wang, Nan Meng, Yong Jun Shao, and Chun Li Li. "Progress in Adjustment of Ionic Liquids Acidity Based on the Alkylation." Advanced Materials Research 634-638 (January 2013): 581–86. http://dx.doi.org/10.4028/www.scientific.net/amr.634-638.581.

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Acidity is a very important character of ionic liquids, which determines the application of ionic liquids in catalysis. In some cases, the adjustment of ionic liquids acidity becomes important and necessary. Focusing on acidic ionic liquids, researches on determination of acidity, application of acidic ionic liquids in alkylation, acidic adjustment methods and novel acidic ionic liquids were reviewed. Finally the development of acidic ionic liquids is discussed.
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Lim, Sung-Chul, Hyoin Hwang, and Song Iy Han. "Ellagic Acid Inhibits Extracellular Acidity-Induced Invasiveness and Expression of COX1, COX2, Snail, Twist 1, and c-myc in Gastric Carcinoma Cells." Nutrients 11, no. 12 (December 10, 2019): 3023. http://dx.doi.org/10.3390/nu11123023.

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Extracellular acidity has been implicated in enhanced malignancy and metastatic features in various cancer cells. Gastric cancer cell lines (AGS and SNU601) maintained in an acidic medium have increased motility and invasiveness. In this study, we investigated the effect of ellagic acid, a plant-derived phenolic compound, on the acidity-promoted migration and invasion of gastric cancer cells. Treating cells maintained in acidic medium with ellagic acid inhibited acidity-mediated migration and invasion, and reduced the expression of MMP7 and MMP9. Examining regulatory factors contributing to the acidity-mediated invasiveness, we found that an acidic pH increased the expression of COX1 and COX2; importantly, expression decreased under the ellagic acid treatment. The general COX inhibitor, sulindac, also decreased acidity-mediated invasion and expression of MMP7 and MMP9. In addition, acidity increased the mRNA protein expression of transcription factors snail, twist1, and c-myc; these were also reduced by ellagic acid. Together, these results suggest that ellagic acid suppresses acidity-enhanced migration and invasion of gastric cancer cells via inhibition of the expression of multiple factors (COX1, COX2, snail, twist1, and c-myc); for this reason, it may be an effective agent for cancer treatment under acidosis.
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Chang, Jui-Cheng, Che-Hsuan Yang, I.-Wen Sun, Wen-Yueh Ho, and Tzi-Yi Wu. "Synthesis and Properties of Magnetic Aryl-Imidazolium Ionic Liquids with Dual Brønsted/Lewis Acidity." Materials 11, no. 12 (December 13, 2018): 2539. http://dx.doi.org/10.3390/ma11122539.

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A series of unique tunable aryl-imidazolium magnetic ionic liquids (MILs) with dual acidity that contain both Brønsted and Lewis acidic sites (abbreviated as B-L MILs) were synthesized and characterized using nuclear magnetic resonance and mass spectrometry. Physical properties, such as thermal properties, magnetic susceptibility, and Brønsted and Lewis acidity, were measured. These properties were found to depend on the cation structure. These B-L MILs had good solubility in many organic solvents, good thermal stability, and low melting points, and exhibited magnet-like behavior. For these B-L MILs, the Brønsted acidity was measured using ultraviolet-visible (UV-Vis), and the Lewis acidity was measured using Fourier transform infrared spectroscopy (FTIR). The results showed that B-L MILs with an electron-withdrawing group in the aryl-imidazolium moiety had higher Brønsted acidity, whereas those with an electron-donating group had higher Lewis acidity. This type of ionic liquid, with both Brønsted and Lewis acidic sites, is expected to be a useful solvent and catalyst for organic reactions.
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Devi, M. M., D. Bhattacharyya, K. N. Das, D. K. Patgiri, K. Kurmi, H. Saikia, and K. D. Devi. "Dynamics of Acidity Component of the Soils as Influenced by Liming in Upper Brahmaputra Valley Zone of Assam, India." Ecology, Environment and Conservation 29 (2023): 131–36. http://dx.doi.org/10.53550/eec.2023.v29i02s.025.

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An incubation study was conducted to investigate the effect of lime (CaCO3 )on the acidity components in Upper Brahmaputra Valley Zone (UBVZ) of Assam. Fourteen(14) geo-referenced soil samples were collected from Sibsagar and Jorhat districts of Assam. Soils were treated with 3 different doses of lime viz. 10 per cent Lime Requirement (LR10), 25 per cent Lime Requirement (LR25) and 50 per cent of Lime Requirement (LR50) and initial properties were recorded before liming. Samples were incubated in laboratory at different period of time viz. 15, 30, 60 and 90 days after liming (DAL) with moisture content at Field Capacity (0.33 bar). At four different intervals, soils were analysed for soil acidity components viz. total acidity, exchange acidity, exchangeable Al3+ and exchangeable H+. The soil of Upper Brahmaputra Valley Zone (UBVZ) of Assam were highly acidic to moderately acidic, sandy loam to silt loam in texture with high OC content ranged from 0.72 to 2.59%. The Cation Exchange Capacity (CEC) value ranged from 7.8 to 14.2 cmol (p+)/ kg. Application of lime brought about mark decreased in acidity components viz. total acidity, exchange acidity, exchangeable aluminium and exchangeable hydrogen. Soil acidity components recorded highest decreased at 90 DAL @ LR50 and decreased started from 15 days onwards. The findings of the investigation showed that liming @ LR10 was found effective in reducing soil acidity. The residual effect of lime was found persisting till 90 days. However, the magnitude of lime was increasing with increase in application of lime@ from LR10 to LR25 and to LR50.
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Abure, Tesfaye. "Status of Soil Acidity under Different Land Use Types and Soil Depths: The Case of Hojje Watershed of Gomibora District, Hadiya Zone, Southern Ethiopia." Applied and Environmental Soil Science 2022 (November 12, 2022): 1–13. http://dx.doi.org/10.1155/2022/7060766.

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In the humid regions of Ethiopia, soil productivity and fertility are significantly affected by soil acidity, which is connected to infertility and mineral toxicity. The study aimed to assess the status of soil acidity under different land use types and soil depths in Hojje watershed of Gomibora district, Hadiya Zone, Southern Ethiopia, in November 1, 2020. Soil samples (24 nos.) were collected using X-design format from four different land use typeshome garden, cultivated land, grazing land, and Eucalyptus plantation at two soil depths (0–20 cm and 20–40 cm). The soil samples were prepared, their physiochemical characteristics were examined, and statistical analysis was performed. The results indicated that the soil under cultivated land and Eucalyptus plantation were strongly acidic (pH 5.15 and 5.32) with mean values of exchangeable acidity (4.6, 4.59 cmol(+) kg−1) and acid saturation percentage (47.85, 46.96%), respectively. The grazing land was moderately acidic (pH 5.63) and home garden soil was slightly acidic (pH 6.67). The home garden soils had statistically significant ( p < 0.01 ) lower exchangeable acidity (0.64 cmol(+) kg−1) and acid saturation percentage (2.61%). Although, soil pH (H2O and KCl), exchangeable acidity, acid saturation percentage, exchangeable base, CEC, and base saturation are significantly ( p < 0.01 ) affected by both the main effect and interaction effects of the two factors. As a result, it is advised to apply lime to the cultivated land to reduce the acidity of the soil for profitable crop production as the amount of acidity is above the tolerance limit for the area’s locally produced crops.
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Shalaby, Khaled. "Effect of Olive Oil Acidity on Skin Delivery of Diclofenac: In Vitro Evaluation and Ex Vivo Skin Permeability Studies." Journal of Biomedical Nanotechnology 18, no. 1 (January 1, 2022): 234–42. http://dx.doi.org/10.1166/jbn.2022.3219.

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Olive oil is a vegetable oil which has been successfully used as a skin penetrating agent. Acidity of olive oil is considered as one of the characteristic properties of olive oil. Olive oil acidity was selected as a parameter under investigation for evaluation of skin permeability. The acidities of the three investigated olive oils are varying from 0.75±0.16 to 2±0.17. Olive oil with acidity equals 2.0 showed the highest skin permeation for 12 h and cutaneous deposition with significant difference compared to the permeation values of 0.75 and F1.4 acidities. Results of cutaneous secretion of cytokines suggested that higher penetration was accompanied higher cytokines’ secretions. Olive oil with acidity equals 2.0 also showed more prominent skin changes which suggested to be due to acidity and fatty acids’ content. These results suggest that olive oil might improve the epidermal permeability, which is more pronounced in highly acidic olive oil, through weakening of skin barriers followed by acting of cytokines on re-building effective barriers. Finally, based on the current study, highly acidic olive oil is more efficient skin permeation enhancer vehicle than less acidic ones and can be efficiently used in formulation of cutaneous drug delivery systems.
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KUMAR, MANOJ. "Rising levels of soil acidity in Meghalaya: Evidences and Imperatives." Annals of Plant and Soil Research 23, no. 3 (August 1, 2021): 297–303. http://dx.doi.org/10.47815/apsr.2021.10073.

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In order to examine the current status of soil acidity in Meghalaya, representative soil samples (n= 497) were collected (during 2015-2016) from across the state and analyzed for soil acidity and associated parameters. Averaged across the samples, pH of the soils was found to be very strongly acidic (4.94). Nearly 20 % of the soils had pH below 4.50, 59% below pH 5.0 and 80% below pH 5.50. Only 3.4% of the samples recorded pH more than 6.0. East Khasi Hills District had the maximum percentage (95.1%) of strongly acidic soils (pH ≤ 5.50) while Garo Hills had the least (50.2%). All other districts recorded more than 85% of the strongly acidic soils. Average exchangeable acidity, exchangeable Al and effective CEC were found to be 1.60, 1.27 and 3.86 meq/100g soil, respectively. Mean base saturation was recorded below 60%. Aluminium saturation (percentage of effective CEC being occupied by exch. Al) ranged from 1.5 to 79.7% with its mean value being as high as 33%. Principal component analysis provided three PCs with Eigen values >1 and together they explained 83.2 % of the variance in total dataset. The soil acidity in Meghalaya is on rise, with 80.2% of its soils being strongly acidic (pH ≤ 5.50) in contrast to the previous reports of 53% soils being strongly acidic. This calls for widespread adoption of soil acidity ameliorative measures in agriculture of Meghalaya, Northeast India.
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He, Zhaoshuai, Yajie Chou, Hanxin Zhou, Han Zhang, Tanyu Cheng, and Guohua Liu. "A nitroreductase and acidity detecting dual functional ratiometric fluorescent probe for selectively imaging tumor cells." Organic & Biomolecular Chemistry 16, no. 17 (2018): 3266–72. http://dx.doi.org/10.1039/c8ob00670a.

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A dual functional ratiometric fluorescent probe can obviously distinguish acidity, nitroreductase, and nitroreductase in an acidic environment. Confocal fluorescence imaging of A549 cells indicates the probe can detect acidity and expressed nitroreductase in living cells.
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Tilgner, Andreas, Thomas Schaefer, Becky Alexander, Mary Barth, Jeffrey L. Collett Jr., Kathleen M. Fahey, Athanasios Nenes, Havala O. T. Pye, Hartmut Herrmann, and V. Faye McNeill. "Acidity and the multiphase chemistry of atmospheric aqueous particles and clouds." Atmospheric Chemistry and Physics 21, no. 17 (September 10, 2021): 13483–536. http://dx.doi.org/10.5194/acp-21-13483-2021.

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Abstract. The acidity of aqueous atmospheric solutions is a key parameter driving both the partitioning of semi-volatile acidic and basic trace gases and their aqueous-phase chemistry. In addition, the acidity of atmospheric aqueous phases, e.g., deliquesced aerosol particles, cloud, and fog droplets, is also dictated by aqueous-phase chemistry. These feedbacks between acidity and chemistry have crucial implications for the tropospheric lifetime of air pollutants, atmospheric composition, deposition to terrestrial and oceanic ecosystems, visibility, climate, and human health. Atmospheric research has made substantial progress in understanding feedbacks between acidity and multiphase chemistry during recent decades. This paper reviews the current state of knowledge on these feedbacks with a focus on aerosol and cloud systems, which involve both inorganic and organic aqueous-phase chemistry. Here, we describe the impacts of acidity on the phase partitioning of acidic and basic gases and buffering phenomena. Next, we review feedbacks of different acidity regimes on key chemical reaction mechanisms and kinetics, as well as uncertainties and chemical subsystems with incomplete information. Finally, we discuss atmospheric implications and highlight the need for future investigations, particularly with respect to reducing emissions of key acid precursors in a changing world, and the need for advancements in field and laboratory measurements and model tools.
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Das, Dhrubajyoti, E. Veerashekhar Goud, Suresh Annam, S. Jayalakshmi, Gopinadhanpillai Gopakumar, C. V. S. Brahmmananda Rao, N. Sivaraman, Akella Sivaramakrishna, and Kari Vijayakrishna. "Experimental and theoretical studies on extraction behavior of di-n-alkyl phosphine oxides towards actinides." RSC Advances 5, no. 130 (2015): 107421–29. http://dx.doi.org/10.1039/c5ra19090h.

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The extraction behavior of U(vi) & Am(iii) with di-n-alkyl phosphine oxides (DAPOs) was investigated. DAPO behaves like an acidic extractant at low acidity and at higher acidity they extracted via cation exchange mechanism.
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Dissertations / Theses on the topic "Acidity"

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Crowhurst, Lorna. "Acidity in ionic liquids." Thesis, Imperial College London, 2006. http://hdl.handle.net/10044/1/11301.

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Xu, Xiaohan. "Acidity of Lanthanide Clusters." University of Akron / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=akron1619532111562154.

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Smallbone, Kieran. "The role of acidity in tumour development." Thesis, University of Oxford, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.442910.

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Acidic pH is a common characteristic of human tumours. It has a significant impact on tumour progression and response to therapies. In this thesis, we utilise mathematical modelling to examine the role of acidosis in the interaction between normal and tumour cell populations. In the first section we investigate the cell–microenvironmental interactions that mediate somatic evolution of cancer cells. The model predicts that selective forces in premalignant lesions act to favour cells whose metabolism is best suited to respond to local changes in oxygen, glucose and pH levels. In particular the emergent cellular phenotype, displaying increased acid production and resistance to acid-induced toxicity, has a significant proliferative advantage because it will consistently acidify the local environment in a way that is toxic to its competitors but harmless to itself. In the second section we analyse the role of acidity in tumour growth. Both vascular and avascular tumour dynamics are investigated, and a number of different behaviours are observed. Whilst an avascular tumour always proceeds to a benign steady state, a vascular tumour may display either benign or invasive dynamics, depending on the value of a critical parameter. Extensions of the model show that cellular quiescence, or non-proliferation, may provide an explanation for experimentally observed cycles of acidity within tumour tissue. Analysis of both models allows assessment of novel therapies directed towards changing the level of acidity within the tumour. Finally we undertake a comparison between experimental tumour pH images and the models of acid dynamics set out in previous chapters. This analysis will allow us to assess and verify the previous modelling work, giving the mathematics a firm biological foundation. Moreover, it provides a methodology of calculating important diagnostic parameters from pH images.
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Ceciliani, Francesco. "Taster responses to acidity in white wines." Master's thesis, ISA-UL, 2017. http://hdl.handle.net/10400.5/13344.

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Mestrado Vinifera Euromaster - Instituto Superior de Agronomia - UL / Universitá degli Studi di Udine
The aim of this study was to evaluate the responses of a panel of tasters trained to acidity in white wines. The training of tastes and sensations of the mouth was performed in relation to the acidity, sweetness, bitterness and astringency. Next, the tasters were segmented according to vinotype, sensitivity to PROP (6-n-propylthiouracil) and saliva flow. This panel was used to determine the detection and recognition thresholds of tartaric, malic and lactic acids in white wine with 4.2 g / L of total acidity. The detection and recognition thresholds were 1.05 g/L and 1.32 g/L for tartaric acid, 0.85 g/L and 1.06 g/L for malic acid and 1.12 g/L and 1.30 g/L for lactic acid, respectively. These acids were added to an Arinto wine at concentrations 1.5 times higher than the recognition threshold, obtaining responses regarding the flavor effect considering intensity, persistence, salinity and appreciation. There were no differences (p<0.05) in relation to the first 3 parameters, while the appreciation was higher in relation to lactic and malic acids. The statistical treatment of the responses according to the segmentation revealed relationships (p<0.05) between saliva flow and sensitivity to PROP, and between saliva flow and the tartaric acid recognition threshold. The acidity appreciation was higher in men than in women. The results obtained can be used by the wine industry in the sense of adapting the white wines to the preference of the consumers, taking into account the recent trend towards the consumption of cold climate wines.
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Jacob, Daniel J. Hoffmann Michael R. "The origins of inorganic acidity in fogs /." Diss., Pasadena, Calif. : California Institute of Technology, 1985. http://resolver.caltech.edu/CaltechETD:etd-01112005-133508.

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Doherty, Sean Kevin. "Control of pH in chemical processes using artificial neural networks." Thesis, Liverpool John Moores University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247329.

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Kidd, Petra Susan. "Aspects of soil acidity and their effect on plant growth." Thesis, University of Stirling, 1998. http://hdl.handle.net/1893/28841.

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The effects of low pH, AI, organic and phenolic acids on the growth of naturally occurring plant species were determined. The amelioration of Al toxicity by Si and organic acids was also investigated. Plants were grown from seeds in nutrient solutions simulating the ionic composition of soil solutions from five soil types ranging from acidic peat to calcareous soil. Soil solutions were extracted and analysed using centrifugation, with and without an immiscible displacent (1,1, I-trichloroethane), at both low (4000 rpm) and high speed (12000 rpm). Races of Holcus lanatus L. and Betula pendula Roth. from acidic soils (FM and SMM) grew better in low pH solutions (pH< 4.0). In acid-sensitive races Ca absorption was inhibited at low pH. Races of B.pendula from strongly to moderately acidic soils (FM, SMM, KP) were AI-tolerant and effectively excluded Al from shoots. Root elongation and leaf expansion were inhibited by all Al concentrations in races from calcareous soils (KR). Low concentrations of Al stimulated growth in some races of B.pendula (2 and 5 mg Al lˉ¹) and Anthoxanthum odoratum L. (1.3 and 2.7 mg Al lˉ¹). Al (25 and 35 mg lˉ¹) inhibited root and shoot growth in H.lanatus. Si (1500 and 2500 µM Si(OH)₄) addition to nutrient solutions alleviated AI-damage and restored nutrient uptake to values similar to those in plants grown with neither Al or Si. The ameliorative effects of Si were possibly achieved through AI/Si co-deposition in the root cell walls and maintenance of Golgi activity. Si at 1500 µM was beneficial but inhibited growth at 2500 µM. Al and hydroxyaluminosilicates at pH 5.6 were not toxic. Formic and tartaric acid ameliorated Al toxicity by reducing its availability. These organic acids on their own stimulated growth in H.lanatus and Deschampsia flexuosa (L.) Trin. Phenolic acids stimulated growth of H.lanatus in acidic solutions (pH 4.0) but not near-neutral solutions, particularly in races from soils high in phenolics. Addition of plant residue to acidic peats increased the growth of races from calcareous and acidic mineral soils.
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Shoghi, Kalkhoran Elham. "Physico-Chemical Characterization of Drugs: Acidity and Solubility." Doctoral thesis, Universitat de Barcelona, 2013. http://hdl.handle.net/10803/98463.

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The aim of the present work was to contribute to establish robust and high throughput methodology of interest in the "Drug Discovery" step commonly done in pharmaceutical laboratories. This purpose involves the exploration of the possibilities of the potentiometric Sirius methodology to determine both acidity constants and solubilities of drugs and other bioactive compounds and also to do a study about how to improve bioavailability of a model drug, Amphotericine 8, by increasing its dissolution rate. In the first part of this project, the acidic dissociation enthalpies and constants of anilinium, protonated tris (hydroxymethyl)- aminomethane (HTris+), benzoic and acetic acids, have been determined at several temperatures in pure water and in methanol/water mixtures by potentiometry method. The pK(a) values determined by this technique are in accordance with those values determined by ITC method in our laboratory and also with those other values from literature. Also dissociation enthalpies can be obtained from potentiometric pK(a) values by means of the Van't Hoff approach and these obtained values are in agreement with those ones determined directly by calorimetry in our laboratory. In the second part, we focused on studying about solubility. The Chasing Equilibrium method offers an alternative to the classical procedures to measure the solubility of compounds with acid-base properties. The method is fast and yields accurate results. In this work, the solubility of several compounds including acids and bases was determined through the Chasing Equilibrium approach. A study of experimental conditions in terms of sample weight was performed to measure solubilities. The study shows that only a limited range of weights, depending on the nature and solubility of the compounds, is adequate to obtain reliable results. In the third part of this work, the solubility vs. pH profiles of five ionizable drugs of different nature (a monoprotic acid, a monoprotic base, a diprotic base and two amphoteric compounds showing a zwitterionic species each one) have been determined through two different methodologies: the classical Shake-Flask (S-F) and the potentiometric Cheqsol methods using in both instances the appropriate Henderson-Hasselbalch (H-H) or derived relationships. The results obtained independently from both approaches are consistent. A critical revision about the influence of the electrolyte used as buffering agent in the S-F method on the obtained solubility values is also performed. Thus, some deviations of the experimental points with respect the H-H profiles can be attributed to specific interactions between the buffering electrolyte and the drug due to the hydrotrophic character of citric and lactic acids. In other cases, the observed deviations are independent of the buffers used since they are caused by the formation of new species such as drug aggregates (cefadroxil) or the precipitation of a salt from a cationic species of the analysed compound (quetiapine). In the forth part, the objective was to compare the dissolution behavior of tablets prepared from solid dispersions prepared in DMSO dissolvent with and without drug-carrier and also with and without surfactants in aqueous and acidic solutions. Amphotericine B was used as a model drug. Two types of carriers were used; mannitol, inulin. Solid dispersions with two different drug loads were prepared by freeze drying method. It was found that the drug dissolution rate in aqueous and acidic solutions was significantly increased in the presence of drug-carrier and surfactants. X-ray powder diffraction revealed that all solid dispersions were fully amorphous.
El objetivo del presente trabajo ha sido contribuir a establecer metodología robusta y de high throughput de interés en la etapa conocida como "Drug Discovery" que tiene lugar en los laboratorios farmacéuticos al inicio del proceso de desarrollo de nuevos fármacos. Este objetivo ha implicado la exploración de las posibilidades de la metodología potenciométrica establecida y comercializada por Sirius Analytical Ltd. para la determinación de las constantes de acidez y de la solubilidad de compuestos bioactivos y también un estudio sobre la mejora de la biodisponibilidad de un fármaco muy insoluble tomado como modelo mediante el aumento de su velocidad de disolución. En la primera parte de esta Tesis se han determinado potenciométricamente las constantes de disociación ácida y la variación de entalpía asociada de dos bases y dos ácidos tomados como modelo en agua pura y en mezclas de metanol/agua (0-60% w/w) a varias temperaturas (25-55°C). Esto ha implicado la puesta a punto de la estandarización del sistema potenciométrico en las condiciones de trabajo. Los valores de pK(a) determinados son concordantes con los que ofrece la literatura. Se han calculado también las entalpias de disociación en los distintos solventes binarios estudiados mediante la ecuación de Van't Hoff a partir de los valores experimentales de pK(a). La consistencia de los resultados obtenidos con los de la literatura, obtenidos directamente por calorimetría, confirma la robustez de la metodología. En la segunda parte de este trabajo, el estudio se centró sobre la determinación potenciométrica de la solubilidad de ácidos y bases mediante el método conocido como Chasing Equilibrium, como alternativa a los procedimientos clásicos de equilibración. El método es rápido y produce resultados precisos. Se ha realizado un estudio sobre las condiciones experimentales óptimas en términos de peso de la muestra para medir eficazmente la solubilidad. El estudio muestra que, en función de la naturaleza y solubilidad de los compuestos, existe un intervalo limitado de peso de muestra adecuado para obtener resultados fiables. En la tercera parte de la presente memoria, se estudian los perfiles de solubilidad en función del pH de cinco fármacos ionizables de naturaleza diferente, un ácido y una base monopróticos, una base diprótica y dos compuestos anfóteros que muestran una especie zwitteriónica cada uno. Se han determinado los perfiles de solubilidad mediante el método clásico de equilibración (Shake-Flak, S-F) y el potenciómétrico y, en ambos casos, se han utilizado las relaciones apropiadas de Henderson-Hasselbalch (H-H) o derivadas. Los resultados obtenidos de forma independiente por ambos métodos son consistentes. Se ha hecho un estudio crítico acerca de la influencia del electrolito utilizado como agente tampón en el método S-F en los valores de solubilidad obtenidos y se han observado algunas desviaciones de los puntos experimentales con respecto a los perfiles esperados que pueden ser debidas a interacciones específicas entre el electrolito tampón y el fármaco. En otros casos, las desviaciones observadas son independientes de los tampones utilizados y se pueden atribuir a la formación de nuevas especies tales como agregados iónicos del fármaco en estudio o la precipitación de una sal a partir de una especie catiónica del compuesto analizado. En la cuarta parte de esta memoria el objetivo ha sido estudiar la velocidad de disolución de comprimidos preparados a partir de dispersiones sólidas de un fármaco modelo con y sin portador del fármaco y también en presencia y en ausencia de tensioactivo en soluciones acuosas neutras y ácidas. Como fármaco modelo se estudió la Anfotericina B y se utilizaron como portadores manitol e inulina y como tensioactivos se ensayaron el deoxicolato de sodio (SDC) y el laurilsulfato de sodio (SLS). La difracción de rayos X reveló que el fármaco en estudio se hallaba en estado amorfo en todas las dispersiones sólidas estudiadas. Se puede concluir que la velocidad de disolución del fármaco se incrementa significativamente en presencia de portador y tensioactivo.
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Godsey, Chad B. "Managing soil acidity in no-till production systems /." Search for this dissertation online, 2005. http://wwwlib.umi.com/cr/ksu/main.

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Halldin, Stenlid Karl Joakim. "Quantum chemical predictions of localelectrophilicity (and Lewis acidity)." Thesis, KTH, Skolan för kemivetenskap (CHE), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-146040.

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Books on the topic "Acidity"

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Ulrich, B., and M. E. Sumner, eds. Soil Acidity. Berlin, Heidelberg: Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-642-74442-6.

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Wherry, Edgar T. Soil acidity. Berlin: Springer-Verlag, 1991.

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A, Auroux, ed. Acidity and basicity. Heidelberg: Springer, 2008.

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Smol, J. P., R. W. Battarbee, R. B. Davis, and J. Meriläinen, eds. Diatoms and Lake Acidity. Dordrecht: Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4808-2.

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Food, Ontario Ministry of Agriculture and. Soil acidity and liming. Toronto, Ont: Ministry of Agriculture and Food, 1991.

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Fraissard, Jacques, and Leonidas Petrakis, eds. Acidity and Basicity of Solids. Dordrecht: Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-011-0986-4.

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Victoria. Parliament. Environment and Natural Resources Committee. Inquiry on the impact and trends in soil acidity: Report of the Environment and Natural Resources Committee. [Melbourne]: Victorian Government Printer, 2004.

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Ananthanarayana, R. Soil acidity and liming in Karnataka. Bangalore: Dept. of Soil Science and Agricultural Chemistry, Agriculture College, G.K.V.K, 1998.

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M, Radojevic, and Harrison Roy M. 1948-, eds. Atmospheric acidity: Sources, consequences, and abatement. London: Elsevier Applied Science, 1992.

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Shamrikova, E. V. Kislotno-osnovnai︠a︡ bufernostʹ podzolistykh i bolotno-podzolistykh pochv Severo-Vostoka evropeĭskoĭ chasti Rossii. Ekaterinburg: UrO RAN, 2005.

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Book chapters on the topic "Acidity"

1

Gooch, Jan W. "Acidity." In Encyclopedic Dictionary of Polymers, 13. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_155.

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Boyd, Claude E. "Acidity." In Water Quality, 215–31. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-23335-8_11.

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Dahlgren, Randy A., Felipe Macías, Marta Camps Arbestain, Ward Chesworth, and Wayne P. Robarge. "Acidity." In Encyclopedia of Soil Science, 10–21. Dordrecht: Springer Netherlands, 2008. http://dx.doi.org/10.1007/978-1-4020-3995-9_9.

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van Breemen, N. "Soil Acidification and Alkalinization." In Soil Acidity, 1–7. Berlin, Heidelberg: Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-642-74442-6_1.

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Bruggenwert, M. G. M., T. Hiemstra, and G. H. Bolt. "Proton Sinks in Soil Controlling Soil Acidification." In Soil Acidity, 8–27. Berlin, Heidelberg: Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-642-74442-6_2.

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Ulrich, B. "An Ecosystem Approach to Soil Acidification." In Soil Acidity, 28–79. Berlin, Heidelberg: Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-642-74442-6_3.

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Hayes, M. H. B. "Influence of the Acid/Base Status on the Formation and Interactions of Acids and Bases in Soils." In Soil Acidity, 80–96. Berlin, Heidelberg: Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-642-74442-6_4.

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Paterson, E., B. A. Goodman, and V. C. Farmer. "The Chemistry of Aluminium, Iron and Manganese Oxides in Acid Soils." In Soil Acidity, 97–124. Berlin, Heidelberg: Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-642-74442-6_5.

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May, H. M., and D. K. Nordstrom. "Assessing the Solubilities and Reaction Kinetics of Aluminous Minerals in Soils." In Soil Acidity, 125–48. Berlin, Heidelberg: Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-642-74442-6_6.

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Sumner, M. E., M. V. Fey, and A. D. Noble. "Nutrient Status and Toxicity Problems in Acid Soils." In Soil Acidity, 149–82. Berlin, Heidelberg: Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-642-74442-6_7.

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Conference papers on the topic "Acidity"

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Lupu, Maribela Ioana, Cristina Maria Canja, Alina Maier, Vasilie Padureanu, and Geronimo Raducu Branescu. "THE EFFECT OF BLUEBERRIES ON PHYSICAL, CHEMICAL AND SENSORIAL PROPERTIES OF TURKISH DELIGHT." In 23rd SGEM International Multidisciplinary Scientific GeoConference 2023. STEF92 Technology, 2023. http://dx.doi.org/10.5593/sgem2023v/6.2/s25.50.

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Turkish delight (lokum) is a sweet product originating in Turkey made from sugar, food flavors and starch. The delights dates back more than 300 years and is one of the oldest sweets in the world. Technologies have evolved and with them the demands of consumers have also diversified. People are in search for everything new and healthy in terms of nutrition, this being the reason for the development of a new kind of Turkish delight. The aim of this study is to analyze the physico-chemical and sensorial properties of two types of blueberries Turkish delight. First type is made from the culture blueberry and the second one is made from the forest blueberry. The physico- chemical properties analyzed for both varieties of blueberries and as well on the finished products are: pH, total acidity, viscosity, dry substance, moisture content, protein, ash, total polyphenol content and the antioxidant activity. It was determined that Turkish delight sample containing forest blueberry it has a greater amount of active biological compounds. According to the results, for the raw material, the pH values indicate that cultivated blueberries are less acidic than wild blueberries. And as for the finished product, compared to the control sample, it is found that due to the thermal process and the concentration of sugar present in the blueberries, the pH value decreases for the two varieties made. Regarding the acidity, it was found that cultivated blueberries have a medium acidity, and forest blueberries have a low acidity. And for the finished product, the Turkish delight obtained with wild blueberries has a higher acidity. From the point of view of sensory analysis, the product obtained from cultivated blueberry puree has higher sensory properties than the one obtained from forest blueberry puree.
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Cejkova, Anna, Pavel Trnka, and Vaclav Mentlik. "Natural ester — Moisture and acidity issue." In 2016 Conference on Diagnostics in Electrical Engineering (Diagnostika). IEEE, 2016. http://dx.doi.org/10.1109/diagnostika.2016.7736475.

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Sun Yaqiao, Zhang Binbin, Duan Lei, and Li Yunfeng. "Effect of gangue acidity release on environment." In 2011 International Symposium on Water Resource and Environmental Protection (ISWREP). IEEE, 2011. http://dx.doi.org/10.1109/iswrep.2011.5893553.

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Watson, Simon A. G., Victor W. Wong, Darrell Brownawell, and Scott P. Lockledge. "Controlling Lubricant Acidity With an Oil Conditioning Filter." In ASME 2009 Internal Combustion Engine Division Spring Technical Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/ices2009-76100.

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In modern diesel engines, acidity generally determines the lubricant drain interval. To control acidity, lubricant suppliers incorporate detergent additives to neutralize acids that accumulate in the oil via exhaust blow-by and base-stock oxidation. However, formulations that meet the most recent diesel lubricant classification specifications typically contain lower levels of detergent since this additive contributes to ash that fouls emissions aftertreatment systems. This study explores a novel approach to lubricant acid control as a potential means to reduce additive requirements or increase oil drain interval. The authors investigate the performance of an innovative oil filter that releases no additives into the lubricant, yet enhances the acid control function typically performed by detergent and dispersant additives. The filter chemically conditions the crankcase oil during engine operation by sequestering acidic compounds derived from engine combustion and lubricant degradation. Long duration heavy-duty diesel engine tests show that the filter reduces both the rate of Total Base Number (TBN) decline and the rate of Total Acid Number (TAN) increase by a factor of two. Analysis by Fourier transform infra-red (FTIR) spectroscopy also indicates that lubricant oxidation may be lowered. In addition, these results suggest a reduction in engine wear. These results imply that lower lubricant additive levels in combination with this novel oil filter may be used to reduce ash accumulation in diesel aftertreatment systems, while maintaining adequate engine protection. The results also indicate that the engine operator may use this oil filter with a state-of-the art lubricant to lengthen oil change intervals.
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Asahi, Kenichi, Yoshiyuki Tani, Ryuichi Yoshida, Koji Shimomura, Yusuke Takano, Yoshino Nishiwaki, and Hatsuyuki Tanaka. "Environmentally stable lithography with acidity-optimized TARC material." In Microlithography 2000, edited by Francis M. Houlihan. SPIE, 2000. http://dx.doi.org/10.1117/12.388359.

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Alanazi, Khalid, R. Mohan, S. S. Kolla, and O. Shoham. "Experimental Study of Monovalent Salt and Hydrochloric Acid Solution Effects on the Stability of Blank Oil-Water Dispersion in Batch Separators." In ASME 2023 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2023. http://dx.doi.org/10.1115/imece2023-112880.

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Abstract The effect of aqueous phase salinity and acidity on the stability of oil-water dispersion is poorly understood. This is because most research works use complex solutions of mixed monovalent and divalent salts to replicate the composition of brine solution in the aqueous phase of crude oil emulsion. Hence, the relevance of each form of ionic solution cannot be determined without isolating and analyzing a laboratory-created oil-water dispersion. Toward this objective, this study aims to investigate the impact of monovalent salt solution and acidic water on the stability of blank (emulsifier-free) oil-in-water (O/W) and water-in-oil (W/O) emulsion. Fluids were mixed at a constant stirrer speed (2,500 rpm) and time (5 minutes) for each investigated emulsion. Mineral oil (EXXSOL™ D110) and distilled water with density and viscosity ratios of 0.805 and 0.330, respectively, were chosen as the pure fluids. Sodium chloride (NaCl) was used to vary the concentration of monovalent salt (from 1 to 60 g/L) in the aqueous phase, whereas a 1.0 M hydrochloric acid solution was used to alter the acidity (pH = 4.80 to 1.88) of distilled water. Experiments ranging from less than a minute to several hours were conducted using four water cuts (WC = 25%, 50%, 75%, and 90%). The brine and acidic water phase had shown large impacts on the stability of O/W (90% and 75% WC) emulsions but had minor effects on W/O (25% and 50% WC) emulsions.
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Mara, Ady, Remi Ayu Pratika, Karna Wijaya, Wega Trisunaryanti, Mudasir Mudasir, Hilda Ismail, Budhijanto Budhijanto, and Asma Nadia. "Aluminosilicate Based Solid Acid Catalyst: Effect of Calcination Time, OH/Al Ratio and Keggin Ion Concentration on its Preparation." In Life Science, Materials and Applied Chemistry. Switzerland: Trans Tech Publications Ltd, 2022. http://dx.doi.org/10.4028/p-mbzzl3.

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The synthesis of acid-activated Al2O3-pillared bentonite as a solid acid catalyst has been completed. The pillarization process was carried out using the varying pf calcination time, mole OH/Al ratio, and mmol of Keggin/bentonite to determine the optimum total acidity. The higher the calcination time, (OH/Al) ratio, and suspension concentration, the greater the acidity of ​​the Al2O3-pillared bentonite. The optimum conditions were achieved at a calcination time of 20 minutes, a mol of (OH/Al) ratio of 2.2, and Keggin/bentonite of 10 mmol with a total acidity of 11.76 mmol gram ammonia and 2.44 mmol/gram pyridine. The pillared bentonite had a surface area of ​​154.64 m2/g and a pore diameter of 3.38 nm. The pillaring process was successfully increasing the basal spacing of natural bentonite from 14.77 to 17.78.
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BEJBLOVÁ, MARTINA, JOSEF VLK, DANA PROCHÁZKOVÁ, HELENA ŠIKLOVÁ, and JIRÍ CEJKA. "LEWIS ACIDITY OF MESOPOROUS MOLECULAR SIEVES FOR ACYLATION REACTIONS." In Proceedings of the 5th International Symposium. WORLD SCIENTIFIC, 2008. http://dx.doi.org/10.1142/9789812779168_0049.

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Grossi, Marco, Bruno Ricco, Giuseppe Di Lecce, and Tullia Gallina Toschi. "A novel electrochemical method for olive oil acidity determination." In 2013 5th IEEE International Workshop on Advances in Sensors and Interfaces (IWASI). IEEE, 2013. http://dx.doi.org/10.1109/iwasi.2013.6576058.

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Noirhomme, B., M. C. Lessard, J. Jalbert, S. Besner, F. Brochu, and E. Dupuis. "Influence of transformer oil acidity on insulating paper degradation." In 2013 IEEE Electrical Insulation Conference (EIC). IEEE, 2013. http://dx.doi.org/10.1109/eic.2013.6554274.

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Reports on the topic "Acidity"

1

Dumesic, J. A. Thermodynamic and kinetic aspects of surface acidity. Office of Scientific and Technical Information (OSTI), January 1992. http://dx.doi.org/10.2172/5569965.

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Dumesic, J. A. Thermodynamic and kinetic aspects of surface acidity. Progress report. Office of Scientific and Technical Information (OSTI), April 1992. http://dx.doi.org/10.2172/10134554.

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Osteryoung, Robert A. Studies of Latent Acidity and Neutral Buffered Chloroaluminate Ionic Liquids. Fort Belvoir, VA: Defense Technical Information Center, March 2000. http://dx.doi.org/10.21236/ada379234.

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Kuhn, K. J., and J. T. Dyke. Measurement of high acidity using a renewable-reagent fiber optic sensor. Office of Scientific and Technical Information (OSTI), February 1995. http://dx.doi.org/10.2172/10116784.

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Vij, Vandana, Ashwani Vij, William W. Wilson, Karl O. Christe, and Jeffery A. Sheehy. Chemistry of N-F Containing HEDM Materials and on Lewis Acidity of LiF. Fort Belvoir, VA: Defense Technical Information Center, October 2000. http://dx.doi.org/10.21236/ada408393.

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Ratliff, Raymond D., and Ethelynda E. Harding. Soil acidity, temperature, and water relationships of four clovers in Sierra Nevada meadows. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station, 1993. http://dx.doi.org/10.2737/psw-rn-413.

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Christe, Karl O., David A. Dixon, Douglas McLemore, William W. Wilson, and Jeffrey A. Sheehy. On a Quantitative Scale for Lewis Acidity and Recent Progress in Polynitrogen Chemistry. Fort Belvoir, VA: Defense Technical Information Center, May 1999. http://dx.doi.org/10.21236/ada411235.

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Haw, James F. NMR Computational Studies of Solid Acidity/Fundamental Studies of Catalysis by Solid Acids. Office of Scientific and Technical Information (OSTI), June 2008. http://dx.doi.org/10.2172/1049372.

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Marinenko, G., and W. F. Koch. Evaluation of methods used for the determination of acidity in "acid rain" samples. Gaithersburg, MD: National Bureau of Standards, 1985. http://dx.doi.org/10.6028/nbs.ir.85-3114.

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Dumesic, J. A. Thermodynamic and kinetic aspects of surface acidity. Progress report, July 1, 1993--June 30, 1994. Office of Scientific and Technical Information (OSTI), June 1994. http://dx.doi.org/10.2172/10154228.

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