Browsing by Subject "Clay"
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Item A mineralogical investigation of the Castell soil clay(Texas Tech University, 1966-08) Rogers, James RobertThe purpose of this investigation was to acquire more information about the clay mineralogy of a soil (tentatively named Castell) developed in the Central Basin Land Resource Area of Texas on Valley Springs gneiss. Stahnke (5^) researched the genesis and did preliminary work on the clay mineralogy. He obtained poor X-ray diffraction patterns of the clay fractions studied; therefore, he was not able to draw direct conclusions as to the exact nature of the mineralogy and genesis of the soil. The first step in this study was to confirm the results obtained by Stahnke, proving that his poor results were not due to laboratory technique.Item A prediction of meander migration based on large-scale flume tests in clay(2009-05-15) Park, NamgyuMeander migration is a complex and dynamic process of the lateral movement of a river due to erosion on one bank and deposition on the opposite bank. As a result, the channel migrates in a lateral direction, which might be a major concern for the safety of bridges during their life span of 75 years. Although there are several existing models for predicting meander migration of a river, none of them are based on the physical model tests on a specific type of soil. A total of eight flume tests are conducted to develop a prediction equation of meander migration in clay. The test results of migration rate follow a hyperbolic function, and spatial distribution of the maximum migration distance is fitted with the Pearson IV function. The proposed equations of the initial migration rate and the maximum migration distance, obtained by a multiple regression technique, are validated with the laboratory data. A new methodology for risk analysis is developed to process a number of predicted channel locations based on each future hydrograph generated in such a way that all the hydrographs have the same probability of occurrence. As the output from risk analysis, a CDF map is created for a whole river representing a general trend of migration movement along with the probability associated with new location of the river. In addition, a separate screen is generated with a CDF plot for a given bridge direction so that bridge engineers can read a specific migration distance along the bridge corresponding to the target risk level (e.g. 1 %). The newly developed components through this research are incorporated with the other components in the MEANDER program which is a stand-alone program and the final outcome of the research team. Verification study of the MEANDER program is conducted with full-scale field data at the Brazos River at SH 105, Texas. The prediction results matched quite well with the measured field data. However, a more extensive verification study for other sites is highly recommended.Item A study of clays from the lower part of a soil developed on tertiary basalt in south-eastern Colorado(Texas Tech University, 1961-05) Panichapong, SamarnNot availableItem Application of a Novel Clay Stabilizer to Mitigate Formation Damage due to Clay Swelling(2014-12-09) Clarke, TimothyClay swelling and fines migration can cause formation damage of hydrocarbon bearing zones and prevent economic realization of oil/gas wells. Identification and management of clay particles in the formation is a necessary component of production and drilling engineers? responsibilities. This research focuses on the application of a cationic inorganic Al/Zr-based polymer clay stabilizer to prevent swelling of smectite particles in a sandstone matrix. Previous work has focused on mitigating fines migration; swelling mitigation is tested here. Berea sandstone cores were injected with a montmorillonite slurry to supplement the very low concentration of naturally occurring swelling clays. The modified Berea cores were subjected to a unique aluminum/zirconium-based clay stabilizer, via coreflood, to determine the effect of the stabilizer as a clay control mechanism. Pressure differential across the core and analysis of the coreflood effluent were used to measure the effectiveness of the treatment. The Al/Zr stabilizer performed well as a means to prevent clay swelling. When compared to an untreated core, permeability loss due to clay swelling and fines migration was negligible. Performance of the stabilizer at different concentrations suggests that an increase in stabilizer concentration does not correlate directly with permeability maintenance.Item Authigenic clays and stylolites in the carbonate reservoirs of the Permian Basin(Texas Tech University, 1997-05) Kumar, AnishAuthigenic clay minerals are found in back-reef carbonate rocks ofthe Upper Permian Artesia Group ofthe northwestern shelf of the Delaware Basin. The authigenic clays are located in the vugs and pore spaces of the carbonates. Stylolites from these rocks do not show clays of authigenic origin, however detrital clays and other minerals such as illite, quartz, feldspar, and pyrite are accumulated in the stylolite seams in these carbonates. Authigenic clays in pores and vugs of carbonate samples were studied using x-ray diffraction, and electron imaging such as SEM, TEM, and STEM. Dickite is the predominant authigenic clay mineral. It occurs mostly in euhedral hexagonal platelets. Authigenic illite is rarely observed, and it occurs as laths and fibers.Item Clay-based materials for passive control of ozone and reaction byproducts in buildings(2016-05) Darling, Erin Kennedy; Corsi, Richard L.; Brown Wilson, Barbara; Juenger, Maria; Novoselac, Atila; Xu, YingTropospheric ozone that infiltrates buildings reacts readily with many indoor materials and compounds that are commonly detected in indoor air. These reactions lead to lower indoor ozone concentrations. However, the products of ozone reactions may be irritating or harmful to building occupants. While active technologies exist (i.e., activated carbon filtration in HVAC systems) to suppress indoor ozone concentrations, they can be costly and/or infeasible for dwellings that do not have these systems. Passive methods of ozone removal are an interest of building environment researchers. This dissertation involves (1) a review of the state of the knowledge on building materials and coatings that are intended to passively remove indoor ozone, especially clay-based materials; (2) a compilation of current data on ozone removal and reaction byproduct formation for these materials; (3) a model for ozone removal effectiveness for a selected clay-based material that is implemented in a hypothetical home; (4) a survey of the effects of a clay-based coating with and without ozone and a reactant source on human perceptions of air quality; (5) an investigation of the long-term potential for passive control of indoor ozone by two different clay-based surface coatings that were exposed to real indoor environments; and (6) development of a location-specific model to estimate the monetary benefits versus costs of indoor ozone control using passive removal materials. The above tasks were completed through ongoing reviews of the literature, experimental studies conducted in small and large environmental chambers, and in the field. Results of these studies suggest that clay or materials made from clay are a viable material for passive reduction of indoor pollution, due in part to clay’s ability to catalyze ozone. Human sensory perceptions of indoor air quality were shown to significantly improve when a clay-based plaster was present in an ozonated environment. Based on modeling efforts, effective passive removal of indoor ozone is possible for realistic indoor scenarios when clay-based materials are implemented. There is a growing number of papers that are published on the subject of clay materials and indoor environmental quality, but few that investigate the longer term impacts and performance of clay materials, especially ones that have been exposed to real indoor environments.Item Clays and associated minerals in caves of the Guadalupe Mountains, New Mexico(Texas Tech University, 1998-05) Polyak, Victor JamesThe clay minerals occurring in caves of the Guadalupe Mountains of New Mexico include kaolinite, dickite, hydrated halloysite, illite, montmorillonite, trioctahedral smectite, and palygorskite. The minerals associated with these clays include alumimte, alunite, natroalunite, jarosite, calcite, dolomite, aragonite, huntite, gibbsite, nordstrandite, goethite, gypsum, hydrobasaluminite, metatyuyamunite, tyuyamunite, quartz, todorokite, and rancieite. The clay minerals found to be authigenic in the caves are hydrated halloysite, montmorillonite, trioctahedral smectite (probably saponite and stevensite), and palygorskite. Hydrated halloysite and alunite are by-products of the sulfuric acid-related speleogenesis that formed many of the larger caves; montmorillonite and illite were altered to hydrated halloysite and alunite. Montmorillonite was found to form in moistened floor and ledge sediments, but these occurrences are not common. Trioctahedral smectite forms in association with Mg-carbonates such as dolomite and huntite in crusts and moonmilks; evolution of the formation of these silicates follows the sequence of carbonate mineral formation. For instance, amorphous silica and poorly formed silicates precipitate with Mg-calcite and aragonite in stalagmites and crusts, while trioctahedral smectite forms in association with the Mg-carbonates. Palygorskite forms in smectite-rich sediments such as the brown laminated silts and green clays of Carlsbad Cavern. Dickite and illite are inherited in wall residues from the dissolution of the cavewall bedrock by condensate or carbon dioxide of the cave air, and/or by biochemical breakdown. Dickite and illite are not cave-authigenic. 40Ar/39Ar dating of alunite from these caves have yielded the formation age of five caves. The apparent ages ranged from 11.3 million years for Virgin Cave located at the higher elevations (2000 meters) to 3.9 million years for the Green Clay Room of Carlsbad Cavern at an elevation of 1090 meters. Alunite ages are strongly correlative with cave elevations. An apparent water table decline of approximately 1100 meters is shown to have occurred from 12 million years ago to the present.Item Design of large diameter monopiles for offshore wind turbines in clay(2016-08) Senanayake, Asitha Indun Madusanka Joshua; Gilbert, Robert B. (Robert Bruce), 1965-; Wang, Shin-Tower; Cox, Brady; Manuel, Lance; Murff, James DOffshore wind power has great potential as a clean and renewable energy source that is capable of reducing our reliance on fossil fuels. The main drawback of offshore wind power is its comparatively high capital cost. One area in which this cost can be reduced is by optimizing the design of these structures. More efficient foundation designs is key in this regard. The p-y method is extensively used for the design and analysis of laterally loaded piles due to its simplicity and versatility. Matlock (1970) or the API RP 2GEO (2011) “soft” clay p-y model is the guideline of choice for normally consolidated to moderately overconsolidated clays. However, this p-y model is not yet verified for piles with very large diameters and low aspect ratios. Design of wind turbine monopiles is governed by serviceability limits such as the natural frequency of the structure and the accumulated tilt under long-term low-amplitude cyclic loads, but these guidelines have not been verified for serviceability limit state designs. The main objectives of this study were to: (a) assess the ability of the Matlock (1970) p-y model to accurately model the behavior of laterally loaded piles at both small and large displacements, (b) investigate the effect of gapping on the backside of laterally loaded piles and develop a theoretical framework to quantify its effect and predict its occurrence, (c) re-examine the derivation of lateral bearing capacity factors (N p ) used in published p-y models, (d) evaluate the effect of large numbers of small-amplitude cyclic load on the stiffness and the post-cyclic ultimate capacity of laterally loaded piles, (e) assess the ability of the Matlock (1970) p-y model to adequately account for pile diameter effects, (f) assess the ability of the Matlock (1970) p-y model to accurately predict the behavior of a pile in a variety of undrained shear strength versus depth profiles, (g) assess the ability of published p-y models to accurately predict the natural frequency of wind turbine structures. The methodology consisted of analyzing field tests, laboratory model tests (1-g and centrifuge), and numerical modeling. An extensive database of field tests and laboratory centrifuge tests was compiled. This data was then supplemented by a series of 1-g model tests in a variety of clay test beds (normally consolidated to heavily overconsolidated, kaolinite and Gulf of Mexico clay) carried out at The University of Texas at Austin and 3-d finite-elements models using Abaqus carried out by Ensoft Inc. The following conclusions were drawn from this study: (a) Matlock (1970) p-y model underestimates the lateral soil resistance on piles in normally consolidated and overconsolidated clays, regardless of pile diameter or aspect ratio, (b) the effect of gapping plays an important role in determining the pile response as it can lead to a loss of capacity and a reduction in stiffness, (c) lateral bearing capacity factors used in the Matlock (1970) model are too low, (d) the degradation in the stiffness of the pile response, when subjected to cyclic loading, was limited to approximately 30% and occurred within the first 100 cycles, (e) the method of normalizing used in the Matlock (1970) model successfully accounts for pile diameter effects, (f) estimates of the natural frequency of wind turbine structure based on the API RP 2GEO (2011) p-y model are lower than those based on the Matlock (1970) and Jeanjean (2009) p-y models.Item Developing and Testing a Trafficability Index for Planting Corn and Cotton in the Texas Blackland Prairie(2010-07-14) Helms, Adam J.The Texas Blackland Prairie is one of the most productive agricultural regions in Texas. This region provides a long growing season coupled with soils that have a high water holding capacity. However, the soils also provide significant challenges to producers because the high water holding capacity is a product of a high clay percentage. This research was aimed to develop and test an expert-based trafficabililty index, based upon soil moisture, for planting cotton (Gossypium hirsutum L.) and corn (Zea mays L.) on the Texas Blackland Prairie. Testing the index focused on quantify the potential effect of high soil moisture at planting on seed furrow sidewall compaction and associated plant growth response. Once the trafficability index was developed, three workable soil moisture regimes were recreated in no-tillage and conventional tillage plots at the Stiles Farm Foundation in Thrall, Texas. The index nomenclature included: "Dry-Workable", "Optimal" and "Wet-Workable". After planting corn and cotton into conventional and no tillage plots, 0.45 x 0.20 x 0.15 m intact soil blocks were removed from each plot and kept in a controlled environment. At 28 days, each block was destructively harvested to quantify plant root and shoot growth responses. Each of the three soil moisture indexes was replicated thrice per crop, and the whole experiment was replicated twice in time, n = 48 blocks. The trafficability index was created using three producer experts, and over 10 interviews to collect a range in soil moisture samples. From "Wet Workable" to "Dry Workable", the gravimetric soil moistures were 0.17, 0.22, and 0.26 g g-1. For corn and cotton, a positive relationship between plant growth factors and planting at soil moisture existed. Plants planted at the highest soil moisture emerged faster and developed more root and shoot biomass than those planted at the lowest soil moisture. No evidence of a detrimental plant response because of seed furrow, sidewall compaction from planting at too high a soil moisture content could be quantified. Furthermore, the cotton plants in no-tillage performed better than in conventional tillage, but corn performed better in conventional tillage. Because the results showed an advantage to plant growth by planting in the "Wet Workable" index, the tillage practice that allows the producer to enter the field with a planter at higher moisture contents appears to have an advantage.Item Development of ASP formulations for reactive crude oil in high clay, high temperature reservoirs(2012-08) Tipley, Kyle Andrew; Pope, Gary A.; Weerasooriya, Upali P.Surfactant formulations consisting of surfactant, alkali, polymer, and electrolyte have been developed using well defined screening processes established through experimentation in labs around the world. Due to recent advances in chemical enhanced oil recovery, surfactants can be used to extend the life of mature reservoirs with increasingly diverse conditions. High temperatures, complex geochemistry, or high clay content can provide significant challenges when developing formulations for chemical flooding. Through careful selection and screening of surfactants and chemicals, oil recovery of greater than 90% can be achieved in laboratory corefloods despite these difficulties. The objective of this research was to determine the ideal surfactant formulation using a sulfate surfactant for a reservoir with high clay content at 85 ºC. Advances in our laboratory have shown sulfate surfactants to be stable under specific conditions at elevated temperature. In addition, new methods of synthesizing surfactants have yielded a vast array of structures and iterations of novel surfactants to test for EOR applicability. Experiments contained within include surfactant screening both with and without the presence of crude oil and evaluation of polymer and microemulsion viscosity. From these results, a series of corefloods were performed in Berea and reservoir corefloods that yielded oil recovery of 90% and above with low surfactant retention.Item Identifying and mapping clay-rich intervals in the Fayetteville Shale : influence of clay on natural gas production intervals(2013-12) Roberts, Forrest Daniel; Tinker, Scott W. (Scott Wheeler); Fisher, W. L. (William Lawrence), 1932-The Fayetteville Shale is composed dominantly of clay, carbonate, and siliciclastic minerals. A variety of facies have been described by other workers and in this study, defined by mineral content, biota, fabric, and texture. Because the Fayetteville Shale is one of the top shale-gas producing plays in the U.S., an inquiry into key drivers of good-quality production is worthwhile. In particular, a hypothesis that intervals of high clay content should be avoided as production targets is investigated in this study. A high level of separation between wire-line log neutron porosity (NPHI) and density porosity (DPHI) in the Fayetteville Shale is observed in contrast to the wire-line log responses from the Barnett and Haynesville Shales. Clay minerals have a significant effect on NPHI, which in turn affects separation between NPHI and DPHI (PHISEP). X-Ray Diffraction (XRD) clay data was available for three wells, and efforts to correlate XRD results to PHISEP led to establishing NPHI as a reasonable proxy for clay. Using NPHI as a proxy it was possible to pick clay-rich intervals, map them across the study area, and to determine net clay in the Fayetteville Shale. Maps of net clay-rich intervals were compared to a map of production, but revealed no obvious correlation. Stratigraphic cross-sections showing the clay-rich intervals revealed a clay-poor interval in the upper part of the lower Fayetteville. This interval is the primary target for horizontal well completion. It is bounded above and below by more clay-rich intervals. Establishing the clay-rich intervals via porosity log separation (PHISEP) is one tool to help determine possible stratigraphic zones of gas production and can lead to a better understanding of intervals in which to expect production.Item Impacts of a clay plaster on actual and perceived indoor air quality(2011-08) Darling, Erin Kennedy; Corsi, Richard L.; Ying, XuPassive removal materials (PRMs) are building materials or furnishings that can effectively control indoor pollution without substantial formation of chemical byproducts and without energy penalty. To assess clay wall plaster as an effective PRM for improving air quality by controlling ozone, perceived air quality (PAQ) was determined in the presence of eight combinations of an emitting and reactive pollutant source (new carpet), clay plaster applied to gypsum wallboard, and chamber air with and without ozone. A panel of 18 to 23 human subjects assessed air quality in twin 30 m3 chambers using a continuous acceptability scale. Air samples were collected immediately prior to panel assessment to quantify concentrations of C5 to C10 saturated n-aldehydes and two aromatic aldehydes that are commonly produced by reaction of ozone with carpet. Perceived Air Quality was most acceptable and concentrations of aldehydes were lowest when only clay plaster or both clay plaster and carpet were present in the chambers without ozone. The least acceptable PAQ and the highest concentrations of aldehydes were observed when carpet and ozone were present together; addition of clay plaster for this condition improved PAQ and considerably decreased aldehyde concentrations. Ozone deposition and byproduct emissions of the clay wall plaster were also assessed using 48 liter stainless steel chambers. Clay plaster applied to gypsum wallboard that had been exposed in a test house (UTest House) for one year effectively removed 88% of the ozone, and emitted high aldehyde concentrations when exposed to high purity air that did not increase when the material was exposed to ozone. The outcome of these experiments leads to speculation that the clay plaster adsorbed contaminants in the test house and then re-emitted them upon exposure to clean air in the small chambers.Item Mineralogy of the playa clays at the Pantex plant, Amarillo, Texas(Texas Tech University, 1996-08) Mars, Kenneth R.The Southem High Plains of Texas contains approximately 20,000 small ephemeral lake basins called playas. Recentiy, these playas have received considerable attention due to the realization that focused recharge to the Ogallala Aquifer can occur through these basins (Wood and Osterkamp, 1984, 1987; Scanlon et al., 1994; Wood et al., 1996). The Pantex Plant, located 16 miles northeast of Amarillo, Texas, in Carson County, has five playa lakes on property owned or leased by the Department of Energy. Potential contamination of the Ogallala Aquifer from Pantex has created much concern. Measurable contamination has been detected in the soils underlying the Plant (Laun, 1995). A sufficient knowledge of soil properties in playa basins is necessary to properly characterize the potential of contamination. Playa basins are a major focus of surface mnoff on the Southem High Plains. Playa basins have a distinctive surface soil, termed the Randall soil series (USDA-SCS unpublished material, 1978). Randall soils are defined as fine, montmorillonitic, thermic typic Halplustert. Playa basins collect mn-off from agricultural fields, roads, pavement and other man-made stmctures that can be sources of contamination. Mineralogy influences factors such as recharge and contaminant attenuation through these basins.Item Nanocomposites of poly(acrylonitrile-butadiene-styrene) and montmorillonite clay: dispersion and mechanical properties(2005) Stretz, Holly Ann; Paul, Donald R.Item Performance of drag embedment anchors dragged through remolded clay and loaded at various horizontal orientations(2009-12) Lynk, John Michael; Gilbert, Robert B. (Robert Bruce), 1965-; El Mohtar, ChadiDrag embedment anchors (DEAs, or anchors) are used as foundations to secure mobile offshore drilling units (MODUs) in soft clay soils on the sea floor. In 2004 and 2005, Hurricanes Ivan, Katrina, and Rita caused the mooring failures of 17 mobile offshore drilling units moored with anchors. Since then, a great deal of research has been conducted regarding anchor performance and reliability. This report provides an overview of anchor research and industry practice to date, and discusses the results of two research experiments to assess anchor performance. One experiment investigated the effect that embedding anchors in the same soil path several times had on bearing force. The second experiment investigated what effect changing the direction of the horizontal load vector relative to the anchor shank had on embedded anchor bearing force. The results of these experiments suggest that remolding clay may have an effect on anchor bearing force capacity, and that repeatable results are obtainable when testing the effect of changing the direction of applied horizontal load.Item Reconstructive-memory process(2012-05) Shin, Yun Koung; Mutchler, Leslie; Goodman, MarkThis graduate report is a description of my artistic development through the graduate program at the University of Texas at Austin. It records my development and growth as an artist in relationship to the concepts, materials, and processes I have been investigating and exploring in the past three years. The graduate report focuses on three important concerns to which I’ve been dedicated. First, materials are imperative to my work. I physically collect and use my father’s ordinary objects and transform them with raw materials, such as clay, flour, honey, chocolate, beeswax, and petroleum jelly. The decision of choosing raw materials is based on my personal and cultural experiences. I am particularly interested in exploiting raw materials because I believe these raw materials can trigger a particular memory, place, or relationship that I want to preserve and remember. Second, my process of making involves ritualistic aspects with repetitive acts. I believe that everyday practices are a way of reconstructing relationships and remembering home. I am interested in embracing emotional attributes that may be simple activities: spraying a piece daily to keep it wet or sewing a personal object until it is impossible to sew. Finally, through the relationship among the objects, repeated actions, and an anticipation that evokes magical power and charged energy, I methodically transform objects. I do this to celebrate emotions and to preserve not only these personal objects but also my memories of home.Item Reliability in the prediction of transit time through compacted clay liners(Texas Tech University, 1995-05) Pulapaka, Srinivas SrikanthAll engineering designs involve uncertainties to some degree. Such uncertainties may arise due to incomplete or inconsistent input information or non-representative analysis procedures used in the design. The input information typically includes design parameters such as material properties and applied loads. Uncertainties in the estimation of material properties can result from material variability or deficiencies in the test procedures used to determine them. Similarly, uncertainties in the determination of the design loads can result from their random variability. The approach which has been traditionally used in engineering designs to incorporate such uncertainties involve the use of "Factors of Safety". In this approach, no attempt is made to quantify the variabilities or uncertainties involved. Instead, the choice of an appropriate factor of safety is made subjectively depending on the degree of uncertainties involved. In other words, the greater the uncertainties in design input information, the larger the selected factor of safety will be. An alternative and a more rational approach to incorporate uncertainties in engineering design involve the concepts of reliability. Reliability is defined as the probability that the structure will not fail during its intended service life. The concept of reliability has been widely used in the fields of aerospace engineering, industrial engineering and mechanical engineering over several decades. Its advent to the geotechnical engineering is more recent. However, it is apparent that in the last two decades geotechnical engineers have developed an interest in the use of probabilistic and statistical approach to solve problems in soil mechanics. Within geotechnical engineering the probabilistic concepts have been used to investigate a variety of problems: slope stability by Christian et al. (1992) and Vanmarcke (1977), pile foundation design and mudslope failure potential by Lee et al. (1992) and most recently to compacted soil liners for hazardous waste containing facilities by Bogardi and Kelly (1990) and Benson (1994).Item Smectite clay adsorbents of aflatoxin B1 to amend animal feed(2009-05-15) Kannewischer, InesSmectite clay has been shown in studies over the past 20 years to sorb aflatoxin B1 (AfB1) in animal feed and thereby reduce its toxic influence on animals. In this study, 20 smectite samples were selected from industrial products or reference minerals. In the initial steps, it was shown that AfB1 entered the interlayer galleries of smectites and a 10-fold range in sorption ability was observed in a set of 20 smectite samples. Yet, it was not clear which clay properties (CEC, pH, base saturation) influenced this variation. In an effort to further explore properties that might influence the sorption of AfB1, three good sorbent samples were chosen from our set of 20 samples along with one sample of low sorption capacity. Those samples were fractionated into sand, silt, coarse clay (CC), and fine clay (FC) fractions. From all sample fractions, sorption isotherms and X-ray diffraction patterns were obtained. Additionally, a vermiculite and a palygorskite were examined with regard to sorption capacity. Concentration of smectite and their adsorption test suggest that differences in smectite composition are responsible for difference in sorption, not so much their relative abundance or other mineral phases. Initial infrared analysis indicates that weathered aluminous smectites, which have no octahedral iron or magnesium, belong to the poor AfB1 sorbents. Palygorskite and vermiculite are not effective sorbents. Based on the findings in this study, tentative quality criteria of sorbent selection for their use in animal feed were established. These criteria are: pH between 6.5 and 8.5, CEC > 75cmolc/kg, organic carbon < 2.5 g/kg, expression of XRD smectite peak and AlFeOHbending in FTIR and Langmuir adsorption capacity for AfB1 > 0.40 mol/kg.