Swelling-activated Cl− current (ICl,swell) is an outwardly-rectifying current that plays an important role in cardiac electrical activity, cellular volume regulation, apoptosis, and acts as a potential effector of mechanoelectrical feedback. Persistent activation of ICl,swell has been observed in a number of models of cardiovascular disease. Previously we showed that angiotensin II (Ang II), endothelin-1 (ET-1), endothelial growth factor receptor (EGFR), and reactive oxygen species (ROS) produced by NADPH oxidase (NOX) and mitochondria are involved in the activation of ICl,swell by both osmotic swelling and Beta1 integrin stretch. Sphingolipid metabolism is modulated in several cardiopathologies and because sphingolipids are bioactive lipids involved in signaling cascades that overlap significantly with these modulators of ICl,swell, we investigated the role of sphingolipids in the regulation of ICl,swell in cardiac ventricular myocytes. Under isoosmotic conditions that isolate anions currents, addition of exogenous, cell permeant C2-ceramide (C2-Cer) elicited an outwardly-rectifying Cl− current that reversed near the Cl− equilibrium potential (ECl) in both physiological and symmetrical Cl− gradients. This current was inhibited by the ICl,swell-specific blockers DCPIB. Dihydro-C2-ceramide (C2-H2Cer), the inactive analogue of C2-Cer, failed to elicit current. These data strongly suggest that the identity of C2-Cer-induced Cl− current is ICl,swell and indicate that sphingolipid signaling pathways may be involved. Bacterial sphingomyelinase (SMase), which converts endogenous sphingomyelin in the outer leaflet of the sarcolemmal membrane to native chain-length ceramides, elicited a DCPIB-sensitive Cl− current. SMase-induced current is also suppressed by tamoxifen, which under conditions that isolate anion currents is a specific inhibitor of ICl,swell. SMase-induced ICl,swell was abrogated by ebselen, a membrane permeant glutathione peroxidase mimetic that dismutates H2O2 to H2O. This suggests that ROS are required mediators of SMase-induced activation of ICl,swell. Both NOX and mitochondria are important sources of ROS in cardiomyocytes and both have been implicated in modulating ICl,swell. Blocking NOX with apocynin or the NOX fusion peptide inhibitor gp91ds-tat had no effect on SMase-induced current. However, pretreatment of cardiomyocytes with gp91ds-tat reduced the maximum current amplitude of SMaseinduced ICl,swell, indicating that NOX may play a time-dependent role in this mechanism. By contrast, the mitochondrial Complex I blocker rotenone, which suppresses extramitochondrial ROS release by Complex III, completely suppresses SMase-induced ICl,swell. Additionally, SMase-induced ICl,swell is partially inhibited by blockade of mitochondrial KATP (mitoKATP) channels with 5-hydroxy-decanoic acid (5-HD). MitoKATP channels have been implicated as modulators of mitochondrial ROS release. Thus these data suggest that mitochondrial ROS generation is required for SMaseinduced activation of ICl,swell. Ceramides are metabolized to form several sphingolipids, including sphingosine-1-phosphate (S1P). We tested whether ceramide metabolites are responsible for eliciting ICl,swell. Under isosmotic conditions that isolate anion currents, SMase-induced ICl,swell was abrogated by blockade of ceramidase, which converts ceramide to sphingosine, with Derythro-MAPP. SMase-induced ICl,swell also was suppressed by inhibition of sphingosine kinase with DL-threo-dihydrosphingosine. These data suggested that the ceramide metabolite S1P is likely to stimulate ICl,swell. As expected, exogenous S1P elicited an outwardly rectifying Cl− current that was fully inhibited by DCPIB. As seen with SMaseinduced ICl,swell, S1P-induced ICl,swell was fully inhibited by rotenone. In contrast to results with SMase, S1P-induced current was partially inhibited by blockade of NOX with apocynin. These data indicate that S1P is a necessary component of SMase-induced ICl,swell activation and that the action of exogenous S1P involves ROS from both mitochondria and NOX. Importantly, the fact that exogenous C2-ceramide also activates ICl,swell even though C2-ceramide may not metabolized to S1P in native cells. Thus, it seems likely that ceramides can elicit ICl,swell via S1P and also by a distinct pathway and that both pathways converge at mitochondrial ROS. In order to determine the role of ERK in the proposed signaling pathway that regulates ICl,swell, we examined the effect of ERK inhibitors PD98059 and U0126 on the activation of ICl,swell. Both of these agents partially inhibited SMase-induced activation of ICl,swell, indicating SMase acts through both ERK-dependent and ERK-independent signaling pathways. HL-1 cells are derived from a murine atrial cell line that retains phenotypic characteristics of adult cardiomyocytes. Recently, ICl,swell has been observed in HL-1 cells with similar regulatory mechanisms to those seen in native cells. We showed that SMase elicits an outwardly-rectifying, DCPIB-sensitive Cl− current that reverses near ECl in HL-1 cells. Finally, we confirmed the production of ROS by SMase-induced signaling by flow cytometry in HL-1 cells using the nominally H2O2-selective fluorescent probe CH2DCFDA-AM. Exposure to SMase increased ROS production, as did the positive control H2O2. SMase-induced ROS generation was suppressed by pretreatment with rotenone but was unaffected by pretreatment with gp91ds-tat. These data indicate that exogenous and endogenous sphingolipids elicit ICl,swell in cardiomyocytes by stimulating mitochondrial ROS production. NOX may contribute to the ROS generation, but is not a required step in this mechanism. Sphingolipid signaling is likely to play an important role in stimulating ROS production and activating ICl,swell in a number of cardiovascular diseases.

Approved for public release, distribution is unlimited / Accurate predictions of nearshore wave conditions are critical to the success of military operations in the littoral environment. Although linear spectral-refraction theory is used by the main operational forecasting centers in the world for these predictions, owing to a lack of field studies its accuracy in regions of complex bathymetry such as steep shoals and submarine canyons is unknown. This study examines the accuracy of linear spectral-refraction theory in areas of complex nearshore bathymetry with three months of extensive wave data collected during the Nearshore Canyon Experiment (NCEX) held in the fall of 2003. The field site, off La Jolla California, is characterized by two submarine canyons that strongly affect the propagation of long period Pacific swell. Data from 7 directional waverider buoys, 17 bottom pressure recorders, and 12 pressure-velocity sensors, were examined and compared to predictions made by a high resolution spectral-refraction model. Analysis reveals large spatial variation in wave heights over the area especially in the vicinity of the canyon heads, where wave heights vary by as much as an order of magnitude over a few hundred meters. This extreme variation in wave conditions across the canyons is surprisingly well described by refraction theory with typical errors of nearshore wave height predictions of about 20 percent. / Lieutenant, Royal Australian Navy

Este trabalho apresenta a quantificação da expansão e suas características, principalmente a influência da sucção, em amostras de materiais sedimentares argilosos provenientes da Formação Corumbataí, aflorantes no interior do estado de São Paulo. Foram testadas amostras indeformadas, e amostras destorroadas e compactadas em diferentes umidades, em ensaios de pressão de expansão a volume constante por inundação, e também, com sucção controlada por meio da técnica da transferência de vapor. Foram ensaiadas, ainda, misturas compactadas desse material com bentonita em diferentes proporções, e misturas de bentonita com material não expansivo arenoso oriundo da Formação Botucatu. O controle de sucção foi realizado pelo uso de soluções salinas de NaCl em concentrações preparadas para impor sucções de 40.000, 25.000, 10.000 e 5.000 kPa. Para a realização dos ensaios, construiu-se um sistema de aplicação de cargas e de aquisição automática dos dados de pressão. Para acelerar o processo de umedecimento por vapor, utilizou-se um reservatório externo ligado em uma bomba de ar adaptada para promover a circulação do vapor de ar para dentro da célula edométrica, especialmente construída para esta pesquisa. Os resultados de expansão nos ensaios com inundação mostraram pressões de expansão crescentes com a diminuição dos teores de umidade, e consequente aumento da sucção inicial das amostras ensaiadas, bem como crescentes com o aumento na proporção de bentonita nas misturas, com valores máximos em torno de 700 kPa para o ensaio com a bentonita pura compactada seca. A análise da microestrutura das amostras por meio da porosimetria por intrusão de mercúrio permitiu constatar que as amostras indeformadas apresentaram variação, apenas, nos macroporos após a expansão; e as compactadas na umidade ótima e, posteriormente secas ao ar, não mostraram evolução significativa após a expansão. Na microscopia eletrônica de varredura (MEV) foi possível verificar a mudança nos vazios das amostras, bem como, visualizar a variação na estrutura e na textura. Além disso, no MEV foram confirmados, também, os argilominerais determinados na caracterização mineralógica. Os resultados dos ensaios de expansão com sucção controlada mostraram ausência de pressão de expansão para as amostras da Formação Corumbataí nas condições indeformada, e na condição compactada na umidade ótima e posteriormente seca ao ar. No entanto, esse material, quando compactado seco na forma de pó, e também, compactado seco misturado com bentonita em diferentes proporções, revelou pressões de expansão com a transferência de vapor, assim como, as misturas de bentonita com material não expansivo da Formação Botucatu. A ausência de expansão foi justificada pela forma lenta de umedecimento proporcionada pela transferência de vapor que, apesar de promover o aumento do teor de umidade das amostras, não mobilizou variação volumétrica suficientemente capaz de transmitir como pressão de expansão. Portanto, os ensaios de expansão, com a utilização da técnica de transferência de vapor, foram efetivos para avaliar a expansão somente nos casos em que argilominerais com potencial expansivo estavam presentes em proporções consideráveis. / This thesis presents the quantification and characterization of expansion, especially the influence of suction on samples of sedimentary materials from Corumbatai Formation that occurs in Sao Paulo. Undisturbed and compacted samples with different moisture contents were tested with swelling pressure tests at constant volume method by flooding, and also with suction control by vapour transfer technique. Compacted mixtures of this material with bentonite in differents proportions, and mixtures of bentonite with sandy non-expansive material from the Botucatu Formation were also tested. The suction control was performed by the use of NaCl salt solutions at concentrations prepared to perform 40,000, 25,000, 10,000 and 5,000 kPa suctions. For the tests, it was developed a system for load application and automatic retrieval of pressure. To accelerate the wetting process by vapour, we used an external reservoir connected to an air pump adapted to promote air circulation inside the edometric cell, specially made for this study. The expansion results in flooding tests showed increasing swelling pressure with decreasing moisture content. Consequently there was an increase in the initial suction of the tested samples, which kept increasing as the rate of bentonite was raised in the mixtures, with a peak of ca. 700 kPa for the test with dry pure bentonite compacted. In the microstructure analysis of the samples by mercury intrusion porosimetry, the samples showed variation only in macropores after swell; and the ones compacted at optimum moisture, and subsequently air dried, showed no significant change after the swell. In scanning electron microscopy (SEM) it was possible to verify the change in the voids of the samples, as well as to visualize the variation in the structure and texture. In addition, the SEM confirmed clay minerals deterninated in mineralogical characterization. The results of controlled suction with swell tests showed absence of swell pressure for Corumbatai samples tested in undisturbed conditions, and compacted condition at optimum moisture content, and then air dried. However, when compacted in the form of dry powder, as well as when compacted dry, mixed with different proportions of bentonite, this material showed swelling pressures with vapor transfer technique, as well as mixtures of bentonite with non-expansive material of Botucatu Formation. The absence of swell was explained by the slow damping provided by the vapor transfer that although promoting increasing dampen, did not sufficiently mobilized volume variation capable of transmitting blowing pressure. Therefore, the swell tests with the vapor transfer technique were effective to evaluate the swelling just in cases where clay minerals with swell potential were present in significant proportions.

L’environnement maritime du littoral implique de nombreux processus complexes, mais le manque de données en haute résolution couvrant une large zone sur une longue période est souvent l’obstacle principal à des recherches plus approfondies. Le radar haute-fréquence (HF) est un moyen de faire de la télédétection afin d’obtenir pratiquement en temps réel de l’information sur la surface de la mer et sur une large zone. Ainsi l’étude de l’inversion des paramètres marins à partir de données issues de radars HF est réellement porteuse de sens. Cette thèse fait l’usage d’un jeu de données collectées durant 13 mois par deux réseaux de radar HF à commande de phase pour étudier les caractéristiques de signaux d’échos de la mer, étudier les données à traiter et les méthodes d’inversion, calculer les paramètres de la surface de la mer et évaluer la précision de l’inversion radar des paramètres de la houle.Cette thèse se réfère à l’onde de sol radar HF, dont les ondes radio interagissent avec l’océan du fait de la diffraction de résonance de Bragg. Nous passons en revue l’historique et les applications du radar HF. Nous rappelons les bases de la théorie des ondes électromagnétiques. Nous décrivons les principes d’inversion des courants de surface de la mer, direction du vent et paramètres de houles. La faisabilité de l’inversion de paramètres de houle est examinée. A partir de l’analyse théorique et des études statistiques de nombreux échantillons de données, cette thèse propose une série de méthodes sur le traitement du signal brut et le contrôle de qualité, ce qui inclut la détermination du niveau de bruit, le moyennage des données dans l’espace et le temps, l’identification correcte des pics spectraux, le seuil de largeur de pic, etc. Respectant les caractéristiques de différents processus physiques, les inversions de courant et de vent utilisent des spectres collectés toutes les 20 minutes ; l’inversion des paramètres de houle utilise des spectres moyennés sur 1 heure. Les statistiques des spectres utilisés pour le calcul des paramètres de houle sont présentées pour chacune des stations. Un ensemble de programme efficaces de calculs automatiques avec une complexité algorithme réduite sont développés pour réaliser le traitement et en tirer les paramètres marins.Les vitesses de courants radiales sont obtenues à partir d’une unique station radar. Les champs de vecteurs de courants sont obtenus en combinant chaque station. On montre une année de débit moyen dans la mer d’Iroise, ainsi que le calcul de la vorticité et de la divergence. On étudie un ensemble de données d’un mois du radar SeaSonde de Qingdao. Les schémas de débit moyen, ainsi que la vorticité et la divergence sur un mois sont présentés.La direction relative du vent par rapport à la direction de visée du radar est mesurée à travers le ratio des amplitudes des pics de Bragg. Différents modèles empiriques sont employés pour obtenir la vitesse relative du vent par inversion radar. Les résultats présentés sont en accord avec les estimations prédites par le modèle. Différents modèles de distribution directionnelle sont utilisés pour mesurer le facteur de diffusion pour la mer d’Iroise.Cette thèse se concentre sur l’étude des paramètres de houle. Les résultats sont validés à l’aide de bouées et de données du modèle de vagues (Wavewatch III). L’estimation montre que la précision de la fréquence de houle est très bonne, la précision sur la hauteur significative de houle est très raisonnable et la précision sur la direction absolue de la houle est faible. La cohérence des mesures par chacune des stations radars est vérifiée par comparaison entre les deux. L’utilisation conjointe des échantillons est également prise en charge pour réaliser l’inversion. L’utilisation de deux radars n’améliore pas seulement la précision, mais résout aussi l’ambiguïté de direction relative de houle à partir d’une unique station et donne la direction absolue de vague avec une certaine précision. / Nearshore marine environment contains many complex processes, but the lack of high-resolution data over a large area during a long time is often the primary obstacle to further research. High-frequency (HF) radar is a mean of remote sensing which obtains continuous near-real time sea surface information over a large area. Thus the study of inversion of marine parameters from HF radar data is very meaningful. Thisthesis makes use of a 13-month-long dataset collected by two phased array HF radar to investigate the characteristics of the sea echo signals, study the data processing and inversion methods, compute sea surface parameters and evaluate the accuracy of radarinversion of swell parameters.The thesis refers to the ground wave HF radar, whose radio waves interact with ocean by Bragg resonance scattering. The development history and applications of HF radar is introduced. The basic theory of electromagnetic wave is reviewed. The principles of inversion of sea surface current, wind direction and swell parameters are described. The feasibility of the swell parameter inversion is investigated. Based on theoretical analysis and statistical studies of a large number of samples, the thesis proposes a series of methods on raw signal processing and quality control, including the determination of the noise level, data averaging in space and time, the proper identification of spectral peaks, the peak width threshold, etc. Respecting the characteristics of different physical processes, inversions of current and wind use spectra collected every 20 min; inversion of swell parameters uses one-hour averaged spectra. The statistics of qualified spectra for swell parameter calculations are presented for both stations. A set of efficient, with a reduced computational cost, automatic computing programs are developed to do the processing and derive marine parameters. Radial current velocities are derived from single radar station. Current vector fields are obtained by combination of both stations. One-year mean flow field in the Iroise Sea is shown, together with the computation of vorticity and divergence. A one-month SeaSonde radar dataset off Qingdao is studied. One-month mean flow pattern together with vorticity and divergence are presented.Relative wind direction with respect to radar look direction is measured through ratio of Bragg peaks amplitudes. Different empirical models are employed to derive radar-inverted relative wind direction. Results show reasonable agreement with model estimations. Different directional distribution models are used to measure the spreading factor for the Iroise Sea. The thesis focuses on the study of swell parameters. Results are validated by buoy and wave model (WAVEWATCH III) data. The assessments show that the accuracy of swell frequency is very good, the accuracy of swell significant waveheight is reasonable, and the accuracy of relative swell direction is low.Consistency of measurements by both radar stations is verified by comparison between the two. This also supports the use of double samples to do the inversion. Use of two radars not only further improves the accuracy but also solves the ambiguity of relative swell direction from single station and gives the absolute wave direction to a certain precision. The thesis proposes a constant relative directionmethod to derive swell significant waveheight, based on the studies of radar integral equation and the inverted results of relative swell direction. This proposal is demonstrated to improve the agreement of radar inversion and buoy/model provided significant waveheight and increases significantly the number of samples. The thesis investigates the accuracy of swell parameters obtained by HF radar. Contributions of random errors in radar observations are quantified. Comparing the differences between radar and buoy/model estimations gives assessments of the contribution of radar intrinsic uncertainty and contribution of other factors.

Bentonite clay is widely used in barrier systems due to its low hydraulic conductivity and it high swell capacity. Exposure to inorganic solutions can cause significant increases in hydraulic conductivity, due to changes in the surface chemistry and fabric. This phenomenon can be attributed to a reduction in the thickness of the double layer, due to the cation exchange capacity of the clay. The clay can be modified with polymers to render it less susceptible to chemical attack. The treatment process allows the clay to be engineered to enhance specific properties, such as permeability and sorption. In the present study, engineered soils are prepared by sorbing organic polymers to the surface of Na-bentonite. Three classes, cationic, anionic and nonionic polymers are investigated. The sorbents are water-soluble compounds based on the polymerization of acrylamides (PAM). Mixing and sample preparation techniques are developed and discussed. The interaction of the polymeric compounds and the clay mineral surface are evaluated by testing the liquid limit, swell index and specific gravity of the soils. Permeability tests are performed to determine if the polymer treatment enhances the hydraulic performance of the clay when permeated with highly concentrated salt solutions. The effect of permeant, void ratio, initial wetting condition and preparation techniques are found to have a significant affect on the hydraulic conductivity.

Distributed generation (DG) has received much attention recently due to environmental consciousness and rising of the energy efficiency. However, DG interconnecting to low-voltage distribution system may cause voltage variation, and a lot of single-phase DG or single-phase load may result in voltage unbalance. This thesis presents a distributed-STATCOM (D-STATCOM) to alleviate variation of both positive-sequence and negative-sequence voltages at the fundamental frequency. The D-STATCOM operates as susceptance and conductance at the fundamental positive-and negative-sequence frequency, respectively. The susceptance and conductance commands are dynamically tuned according to voltage fluctuation at the installation location. Therefore, the positive-sequence voltage can be restored to the nominal value as well as the negative-sequence voltage can be suppressed to an allowable level. Computer simulations and experimental results verify the effectiveness of the proposed control strategy.

This study is about the data analysis of wind speed on sea surface, water temperature, atmospheric temperature, and sea waves observations from four buoy stations (Hua-Lian , Hsin-Chu , E-Luuan-Bi and Kin-Men) that belong to Central Weather Bureau Republic of China and Water Resources Agency, and related researches. The period of this study is in winter and summer from 2001 to 2003. Because of the shelter effect from building or hillocks in land, the wind speed on land is abated and not consistent with that on sea. Comparing data form two island stations ( Dongjido and Lanyu) and four buoy stations, the winds around Taiwan are almost the same. That means the monsoon controls the wind direction in summers and winters. Comparing the quantitative results from different wind speed areas in same period of time, the continuity of sea wind is better than that of land wind, especially best in west Taiwan. Also comparing the changes of wind speed in different atmospheric stability layers, wind is stronger in neural than others. Wind speed distribution also showed wind speeds increased when it is far from land, and sea breeze happened near land within 1-2 kilometer. Sea temperature and wind speed are the factors affecting stability. The diurnal variation of air temperature is greater than that of sea and diurnal variation of sea is more significant during winter. Especially along coastal in Eastern Taiwan, the temperature difference between sea and atmosphere could be greater than 10 ¢J, moreover the wind speed on sea surface in Hua-Lian is slow. Therefore, it caused more unstable on sea surface in Hua-Lian. waves could be classified into two types by wave age: swell and wind sea. Swell means because of passing long fetch, the weave height and wave period are saturated and no longer develop. It can¡¦t reveal the effects of sea wind on waves. Therefore, if swell is the major composition of waves, the inaccuracy of calculated stress would be large. On the contrary, when wind sea is the major composition of waves, roughness could be calculated by wave steepness. While analyzing coefficient of momentum flux on sea surface near Taiwan, gust factor under neutral and unstable conditions had different. Gust factor would change with wind speed under neutral condition, but change with stability under unstable condition. In neutral condition, wind speed and drag coefficient are direct proportion and then correlation among p of power law of wind profile, turbulence intensity and gust factor under neutral condition and strong wind are similar, the value close to 0.1.

In order to meet energy needs in world, studies on wave energy, alternative energy, are becoming more and more important with each passing day. The purpose of this study is to identify the wave energy potential along the coastline of Turkey. For this purpose, the data of wind speed and direction, swell and wind wave height, period and direction for certain duration with the six hours time intervals are obtained from ECMWF for the wind and wave climate computations. In order to compute the wind and wave climate at any selected coastal location, software is developed by Serhan Aldogan in his MSc thesis. By the help of the specifically developed software, for every location, by utilizing existing wind data, depending on geographical location of station, in the direction of energy thought to produce, by using calculated average wind speed of storm which is above the selected wind speed u0, characteristics (Hs / Tm) of the waves of this storm and power (P, W/m) per unit length will be calculated. The duration curves for power, Hs and T, can be obtained. The duration curve represents the occurrence of the parameter (wave height, wave period, wave energy or wave power). It can also be called occurrence curve or availability curve. From these curves, for various percentages of the total storm duration, P, Hs and T&rsquo / s values can be determined. Also, in the analysis, the shapes of these curves can provide important information about the available wave energy for the selected coasts.

<p>The focus of this study is on potential problems resulting from construction on expansive soils in Kibaha region, Tanzania. For the fact that most of the affected structures are founded on expansive soils, a clear understanding of the soil behaviour and their interaction with structures, specifically as they relate to shallow foundations, has been of more interest to the study in order to evaluate properly the source of the problem.</p><p>The geotechnical behaviour of expansive clay soils is investigated by looking into the geomorphologic, geological and climatic conditions and mineralogical composition of the soils in the study area. The geotechnical results are linked with the performance of the foundation as well as structures.</p><p>Two sites, representative of known problem-areas in Kibaha were selected for geotechnical tests. Geotechnical site investigation consisted of open trial pits, profile description and the collection of both disturbed and undisturbed samples.</p><p>The collected samples were submitted to soil laboratories at KTH and DIT for mineralogical composition tests, natural water content, density, Atterberg limits and swell tests (free swell and swelling pressure). The results of this investigation indicate that soil in Kibaha contains clay (31%), have high liquid limit (59%) and plastic limit (37%) which indicate high potential swell.</p><p>Since swell potential and swell pressure are key properties of expansive soils, the swell parameters were measured by free swell tests and one-dimensional oedometer swell tests respectively. The free swell ranged from 100% to 150% and the swell pressure was in the region of 45 kPa.</p><p>The properties of expansive soils were confirmed by the x-ray diffraction test which showed the presence of montmorillonite in the soil. It is from this fact that the source of the problem is in the expansive soils coupled with poor building materials.</p><p>Physical conditions of the surveyed properties in the area confirmed the hypothesis of building damages due to poor building materials triggered by expansive soils. In support of the obtained data, the actual behaviour of the foundations is supplemented with prototypes of strip foundations whose performances are to be monitored over a long period. Finally, suggested are the ways forward to solve the problem of foundation on expansive soil.</p>

Because of its low permeability and high swelling characteristics, bentonite is used in various hydraulic barrier systems and in the manufacturing of Geosynthetic Clay Liners (GCLs). Exposure to inorganic solutions containing elevated concentrations of electrolyte can significantly increase their permeability. To enhance the bentonite's chemical resistance to inorganic solutions, the manufacturers of GCL materials introduced propriety soluble polymeric compounds as an additive to bentonite. The resulting materials are referred to as polymer-treated, chemically-enhanced, or contaminant-resistant clays, and are arguably resistant to a host of inorganic chemicals. In this study, the response of both regular and polymer treated bentonite clays to ordinary tap water and inorganic landfill leachate is evaluated using permeability tests, index tests and x-ray diffraction. The results indicate the high dependence of performance on sample preparation techniques, pre-hydration conditions, and first wetting liquid and, to a lesser extent, polymer treatment. The x-ray diffraction results indicate that the samples reached chemical equilibrium during the permeation process, as demonstrated by a full shift in d-spacing from Na-bentonite to Ca-bentonite. Further, the results show that the cation exchange capacity, the clay plasticity ratio, and the swell index appear to be reliable indicators of the hydraulic compatibility of bentonite permeated with inorganic chemicals