Erosion Profile Research Articles

Poly(anhydride-ester) gemcitabine: Synthesis and particle engineering of a high payload hydrolysable polymeric drug for cancer therapy

Gemcitabine (GMT) is a nucleoside analog used in the treatment of a variety of solid tumors. GMT was chemically modified with a hydrolysable linker, and subsequently incorporated into a poly(anhydride-ester) backbone via melt-polymerization, with the active antimetabolite GMT, thus, becoming the repeat unit that makes up this new material, a biodegradable polymer. Characterization of the structure of polymeric GMT (polyGMT) revealed the incorporation of an average 26 molecules of GMT per polymer chain, which corresponds to a drug loading of 58%w/w. The glass transition temperature of the formed polyGMT was determined to be 123 °C. PolyGMT was engineered into nanoparticles (NPs) using a dialysis-based method, with a resulting geometric diameter of 206 ± 38 nm. The particles are easily dispersible and stable in aqueous-based media, with a hydrodynamic diameter of 229 ± 28 nm. The prepared hydrolysable polyGMT NPs demonstrate ultra-long release profile due to the hydrophobic nature of the linker, and as per characteristic erosion behavior of polymers with anhydride-ester bonds. Accelerated in vitro release studies demonstrate the recovery of free GMT upon hydrolysis, with biological activity as assessed by cytotoxicity assays performed in adenocarcinoma human alveolar basal epithelial (A549) and highly metastatic murine osteosarcoma (K7M2) cells lines. The characteristics of polyGMT, including its thermal properties and built in hydrolysable structure, are thus conducive for use in the preparation of drug delivery systems. Engineered structures prepared with polyGMT can maintain their morphology at ambient and physiologically relevant conditions, and free GMT is recovered as the anhydride and ester bonds are hydrolyzed. This work is innovative as for the first time we demonstrate the ability to polymerize GMT in a hydrolysable polymer structure, and engineer NPs of this polymeric chemotherapy. The synthetic strategy allows for tuning of the polymer hydrophobicity and thus potentialize its behavior, including degradation profile, by varying the linker chemistry. Such controlled release hydrolysable polymers with very high drug loading and controlled erosion profiles are relevant as they may offer new opportunities in drug delivery applications for the treatment of malignant neoplasms.

Structural Investigations of Polycarbonates whose Mechanical and Erosion Behavior Can Be Controlled by Their Isomer Sequence

One of the challenges in materials science is to design functional, synthetic polymers that match the desired properties of a specific application. Achieving high stiffness and strength under physiological conditions while maintaining the proper erosion profile is particularly difficult. This challenge is addressed here by synthesizing polymers with sequence control followed by optimal processing of the polymer. A new class of biodegradable, aromatic–aliphatic polycarbonates based on tyrosol, a naturally derived (hydroxy)alkyl phenol with an alternating (altTyPC) or scrambled (scrTyPC) sequence, is reported. AltTyPC contained strictly alternating sequences of diaryl (head-to-head, HH) and dialkyl (tail-to-tail, TT) carbonate backbone isomers; this was accomplished by using preprogrammed diaryl carbonate diol and triphosgene in polycondensation. The scrambled sequence (scrTyPC) of HH, TT, and the aryl-alkyl (head-to-tail, HT) carbonate isomers was obtained by direct polymerization of tyrosol. The isomer sequence had a large effect on the thermal behavior: altTyPC rapidly transitioned from the amorphous phase into a 1D mesophase at 90 °C and then into a 3D crystalline phase at 150 °C before melting at 204 °C; in contrast, scrTyPC remained in a 1D mesophase after extensive annealing at 100 °C for 20 h and melted at 149 °C. The modulus of the oriented, semicrystalline altTyPC films was higher than that of the similarly processed scrTyPC films (5.4 ± 0.3 vs 3.8 ± 0.2 GPa). The erosion behavior was also different: AltTyPC showed more rapid mass and thickness loss over time than scrTyPC. Thus, a combination of sequence control and processing optimization in aromatic–aliphatic polycarbonates gives rise to a new platform of tunable polymers for numerous applications.

Blending of PLGA-PEG-PLGA for Improving the Erosion and Drug Release Profile of PCL Microspheres.

PCL has a long history as an industrialized biomaterial for preparing microspheres, but its hydrophobic property and slow degradation rate often cause drug degeneration, quite slow drug release rate and undesirable tri-phasic release profile. In this study, we used the blending material of PLGA-PEG-PLGA and PCL to prepare microspheres. The microspheres degradation and drug release behaviors were evaluated through their molecular weight reduction rate, mass loss rate, morphology erosion and drug release profile. The hydrophilic PLGA-PEG-PLGA is expected to improve the degradation and drug release behaviors of PCL microspheres. Microspheres in blending materials exhibited faster erosion rates than pure PCL microspheres, forming holes much quickly on the particle's surface for the drug to diffuse out. A higher proportion of PLGA-PEG-PLGA caused faster degradation and erosion rates. The blending microspheres showed much faster drug release rates than pure PCL microspheres. With blending of 25wt% PLGA-PEG-PLGA, the release rate of microspheres speeded up significantly, while, with a further increase of PLGA-PEG-PLGA proportion (50%, 75%, 100%), it accelerated a little. The microspheres with PCL/PLGA-PEG-PLGA of 1/1 exhibited a linear-like drug release profile. The results could be a guideline for preparing microspheres based on blending materials to obtain a desirable release.

Frequency Downshifting in Wave Spectra in Coastal Zone and Its Influence on Mudbank Formation

The evolution of wind waves in coastal zones leads to changes in the shape of the wave spectrum. Along the coast of Kerala, due to the presence of mudbanks during the southwest monsoon, we could observe downshifting of the peak frequency in the wave spectral data. The present study aims at proving the mechanism of frequency downshifting and possible influence of the downshifting process on mudbank formation. The results of SWASH (Simulating WAves till SHore) modeling and bispectral analysis shows that frequency downshifting occurs due to the difference nonlinear triad interactions of the main frequency peak of the wave spectrum with frequencies of the infragravity range independent of the viscosity of the medium. The increase in wave dissipation accelerates frequency downshifting additionally, decreasing the wave energy in the main peak frequency. It is shown that frequency downshifting can be one of the possible wave mechanisms of mudbank formation due to essentially different wave attenuation coefficients at the beginning and end of this process. For muddy cohesive sediments, it will lead to formation with an erosive profile at first and then an accumulative profile, i.e., mudbank formation.

Analysis of development and depth of backward erosion pipes in the presence of a coarse sand barrier

Backward erosion piping (BEP) is a failure mechanism that can affect the safety of water-retaining structures. It can occur when a local anomaly on the downstream side of an embankment causes a concentration of seepage flow at that location. Shallow pipes may then form, progressing in the upstream direction and leading to a collapse of the water-retaining structure. A novel and economically appealing measure against BEP is the coarse sand barrier (CSB), which is now being developed in a multiscale experimental programme in the Netherlands. The method involves placing a trench filled with coarse sand below the blanket layer on the downstream side of the embankment. The CSB prevents the upstream progression of the pipe and significantly enhances resistance to BEP. This paper presents medium-scale laboratory tests involving a range of sands, barrier depths and relative densities. The piping process and the observations of pipe progression in the presence of a CSB are presented, followed by a conceptual model. The presence of a CSB changed the erosion pattern. It resulted in pipe formation perpendicular to the flow direction over the entire width of the barrier before the barrier was damaged. The findings also demonstrate the effect of material properties on pipe initiation, progression and pipe depth. Measurements of the pipe depth are presented and analysed, revealing the significance of pipe depth for understanding the piping process. This analysis shows considerable erosion in the downstream background sand and demonstrates that erosion profiles and measured pipe depths are significantly larger than in BEP tests without a CSB.

Erosion Testing of Environmental Barrier-Coated Ceramic Matrix Composite and Its Behavior on an Aero-Engine Turbine Vane Under Particle-Laden Hot Gas Stream

Abstract Ceramic matrix composite (CMC) has better durability at high temperature and lower material density, as compared to nickel-based superalloys which have been the standard material for hot section components of aero-engines. Among the CMC materials, SiC–SiC CMC is especially promising with its superior mechanical property at a higher temperature. It, however, inevitably needs environmental barrier coating (EBC) to protect the substrate against oxidation. The EBC also needs to have other functions and to meet various requirements. One such very critical requirement is the resistance to sand erosion, although the issue has not been investigated well so far. The primary contribution of this work is to reveal the erosion resistance of the CMC + EBC material with wind tunnel test data of good quality and to demonstrate what erosion behavior the material exhibits in a turbine cascade under particle-laden hot gas stream. In the present work, erosion tests were first carried out in a testing facility with an erosion media of 50 μm silica sand. The tests were conducted under a flow velocity of 225 m/s and a temperature of 1311 K to simulate typical aero-engine conditions, and impact angles of 30, 60, and 80 deg were investigated. The obtained data showed a typical brittle erosion mode, where the erosion rate had a positive dependence on the impact angles. A typical erosion model, Neilson–Gilchrist model, was applied to correlate the data, and the model was shown to have a good agreement with the experimental data once it was properly calibrated. Then, the numerical computation solving particle-laden flow was carried out to predict three-dimensional flow field and particle trajectories across the target turbine cascade. The erosion profile along the airfoil was calculated based on the obtained trajectories and the calibrated erosion model. The trajectories showed that the particles mostly impinged the airfoil pressure surface first and then the rebounded particles attacked the opposite suction surface as well. Accordingly, the predicted erosion profile showed a broad erosion band across the pressure surface and also some slight erosion peak at around the mid-chord of the suction surface.

Systematic Studies on Surface Erosion of Photocrosslinked Polyanhydride Tablets and Data Correlation with Release Kinetic Models.

Photocrosslinkable polyanhydrides that undergo surface erosion are suitable materials for controlled-release drug delivery systems. Investigating the impact of different parameters on their erosion behavior is essential before use in drug delivery systems. Although their synthesis is well-established, parameters that may substantially affect the erosion of thiol-ene polyanhydrides including temperature and pH of the media, the geometry of the polymers, and the media shaking rate (the convective force for the polymer erosion), have not yet been studied. This study explores the effects of different environmental and geometric parameters on mass loss (erosion) profiles of polyanhydrides synthesized by thiol-ene photopolymerization. A comparative study on several release kinetic models fitting is also described for a better understanding of the polymer erosion behavior. The results demonstrated that although the temperature was the only parameter that affected the induction period substantially, the mass-loss rate was influenced by the polymer composition, tablet geometry, temperature, pH, and mass transfer (shaking) rate. With regard to geometrical parameters, polymers with the same surface area to volume ratios showed similar mass loss trends despite their various volumes and surface areas. The mass loss of polyanhydride tablets with more complicated geometries than a simple slab was shown to be non-linear, and the kinetic model study indicated the dominant surface erosion mechanism. The results of this study allow for designing and manufacturing efficient delivery systems with a high-predictable drug release required in precision medicine using surface-erodible polyanhydrides.

Prediction of midfrequency sputtering cathode erosion position with vertical magnetic field

ABSTRACT In this paper, the etching position of a target was predicted using magnetic field simulation. The magnetic field distribution was simulated with the finite element analysis method, the distribution of the magnetic field on the target surface was measured by a Gaussmeter, and the target erosion profile was characterized and compared with that of the simulation results. In this experiment, cylindrical cathode magnets were specially designed to control the etching behaviour at the corresponding bend location. Because the vertical component of the magnetic field at the bend was strongly influenced by the cylindrical magnets, the vertical magnetic field appeared to determine the erosion position, and this position was predicted successfully by the simulation. Furthermore, the deepest etched position was located where the vertical magnetic field component decreased to zero. The results of this paper can be used as a reference in cathode structure design and target utilization optimization.

Comparative in vitro degradation of surface-eroding poly(alkylene carbonate)s

The current study probed and compared the susceptibility of five poly(alkylene carbonate)s, namely poly(ethylene carbonate), poly(trimethylene carbonate), poly(propylene carbonate) and two end-group modified poly(ethylene carbonate)s, to hydrolytic, enzymatic and oxidative degradation in vitro.None of the utilized polymers showed relevant signs of degradation in the pH range of 2–12. However, in the presence of cholesterol esterase and superoxide radical anions, all polymers underwent a significant mass loss without a change of the molecular weight, a clear sign for a surface erosion process. Poly(ethylene carbonate) was the most susceptible polymer to cholesterol esterase and superoxide radical anions and complete degradation occurred within only 4 and 2 weeks, respectively. By contrast, poly(trimethylene carbonate) and poly(propylene carbonate) only lost ~10–25 % of their initial mass under the same experimental conditions. An acetylation and lauroylation of the terminal hydroxyl groups of poly(ethylene carbonate) attenuated the enzyme- and oxidation-triggered surface erosion profile. For cholesterol esterase, >20 % of modified polymer was left after 4 weeks of incubation, while in the presence of superoxide radical anions >20 % remained after 3 weeks.Among the tested poly(alkylene carbonate)s, poly(trimethylene carbonate) and poly (propylene carbonate) revealed higher “stability” towards enzymatic and oxidative surface erosion compared to poly(ethylene carbonate). An end-capping of poly(ethylene carbonate) represents a promising strategy to modify (decelerate) the rate of polymer degradation.

Evaluation of land suitability for coffee plants based on fuzzy logic in Enrekang district

Ecological perspective is important in agriculture, because sustainable agriculture is based on cultivation practices that do not deviate from natural systems. In an ecological perspective, agriculture is based on differences in climate, soil properties, soil morphology that requires different management and processing of agriculture between regions. Research was conducted in Enrekang district with reference to 18 Land systems. This study aimed to assess the land suitability for coffee plants based on geographic information systems using a fuzzy logic approach. Primary data as evaluation criteria were divided into three main components; for potential land erosion, potential flooding and soil profile. Land cover was considered as well. In fuzzy analysis, the value of land attributes was converted to sustainable values (ranging from 0 to 1.0) according the class limits determined based on experience and standard conventional. There was distribution of land suitability for coffee plants in Enrekang district. 65% of the area had the potential to develop coffee plants. The main limiting factor in the development of coffee plants in the study area was the erosion potential, especially the slope.

Monitoring the safety status of a blast furnace hearth using cooling stave heat flux

Hearths are an accident-prone component in blast furnaces. Accidents, especially hearth burnthrough, cause substantial economic losses and even casualties. Ensuring safe operations is a challenging task as it is impossible to directly observe the internal state of a hearth. Measured data from thermocouples arranged in the hearth lining are often used to evaluate the furnace safety status. However, thermocouples are easily damaged due to their long-term operation at high temperatures. This paper proposes an approach to assist in the safety monitoring of a hearth using heat flux from cooling staves. The method is proposed through a series of finite element simulations to construct the heat flux monitoring calculation model. The No. 3 blast furnace of an iron making plant is taken as an example. The three-dimensional finite element simulation method to calculate the monitoring value of the cooling stave heat flux is described in detail. The simulation results demonstrate that the heat flux monitoring of different cooling staves can vary. Even for the same cooling stave, the monitoring value varies with the increased lining erosion. To ensure safe operations, the monitoring value should be updated when the erosion profile of the lining changes significantly.

Experiment and numerical simulation of sand particle erosion under slug flow condition in a horizontal pipe bend

Sand erosion is a common problem in oil and gas field development. An experimental facility was designed and used to study the sand erosion of pipe bend under slug flow. A detachable test pipe bend was designed to measure the weight loss at 36 discrete locations on the pipe bend before and after each experiment. A Computational Fluid Dynamics (CFD) based erosion prediction method was developed to get a further understanding of the erosion. The relationships among the gas and liquid distribution, the sand movement and the erosion profile were analyzed to explain the erosion mechanism. The most severe erosion area of the pipe bend occurs at the axial angle of the elbow between 67.5° and 90° and at the circumferential angle of the elbow between 45° and 90°. The erosion profiles of the pipe wall are dominated by three particle collision mechanisms, namely, micro-cutting, plowing and impact deformation.

A parallel GPU-based computational framework for the micromechanical analysis of geotechnical and erosion problems

Abstract This article deals with the relevance and practical feasibility of micromechanical simulations for their application to general geomechanical problems involving fluid-saturated granular assemblies, whether frictional or cohesive. A set of conceptual and numerical tools is here presented, advocating for a parallel computation using graphical processing units (GPUs) to treat large numbers of degrees of freedom with conventional desktop computers. The fluid phase is here simulated with a particle-resolved approach in the frame of the Lattice Botzmann Method (LBM) while the granular solid phase is modelled as a collection of discrete particles from a Molecular Dynamics DEM perspective. The range of possible material behaviours for the solid granular phase is intended here to cover a broad spectrum from purely frictional to viscous cohesive materials with either brittle or transient debonding features. Specific details of the implementation and some validation cases are put forward. Finally, some exemplary applications in the fields of soil erosion and geotechnical profile installation are provided along with a discussion on the parallel performance of the presented models. The results show that a micromechanical approach can be feasible and useful in practice, providing meaningful insights into complex engineering problems like the erosion kinetics of a soil under an impinging jet or the penetration resistance of a deep foundation in a layered soil profile.

Study on Tube Profile and Heat Transfer Characteristics Under Flying-Ash Erosion

Flying-ash erosion is the prime reason of the tube failure, involving the economy and safety of coal-fired power plants. To address this issue, computational fluid dynamics (CFD) is applied to this paper, which is coupled with the erosion profile calculation based on the dynamic mesh. The tube profile is analyzed under the flying-ash erosion, and the heat transfer process is further taken into account. The results indicate that as time goes on, the impact frequency and the incident angle decrease at the lower angle and increase at the higher angle. With time going on, the peak value becomes smaller at the saddle-shaped erosion rate curve, and the position of the peak value moves towards the higher angle. Meanwhile, both sides of the saddle-shaped curve expand towards the higher angle. That is, the erosion rate and the erosion loss become higher. The Nusselt number grows slightly and the trend grows faster as time goes on. The erosion profile leads to raising the temperature gradient at the angle of 0°, which induces the tube to rupture ultimately.

Procedure of Predicting the Lifetime of the Accelerating Electrode of an Ion-Extraction System of a Gas-Discharge Ion Source

The state of studies on determination of the lifetime of ion thrusters (IT), including their methodology, is analyzed. The erosion of the accelerating electrode (AE) of an ion-extraction system caused by charge-exchange ions is a critical process responsible for the IT lifetime. It is shown that the quickest and most accurate information on the nature of AE erosion and rate at the initial test stage can be obtained by a method based on the use of multilayer coatings, consisting of several pairs of optical contrast materials, preliminarily applied to the AE surface. The method allows the use of simple photographic devices for recording the erosion pattern and is especially efficient in the case of a highly nonuniform nature of erosion. The calculation procedure is presented for the parameters of diagnostic multilayer coatings, including the optimal layer thickness and total coating thickness, which allow data to be obtained on the surface erosion profile and rate, and on the charge-exchange ion current density distribution with the highest resolution during the given test time.

Modeling of inter- and intra-edge-localized mode tungsten erosion during DIII-D H-mode discharges

The relationship between the tungsten gross erosion and the edge-localized mode (ELM) characteristics is investigated for high performance discharges during the dedicated metal rings campaign in DIII-D, using the 1D ‘free-streaming’ ELM model, coupled to a simple analytical TRIM.SP sputtering model, while the OEDGE code is employed to calculate the inter-ELM impurity distribution and tungsten gross erosion. A carbon–tungsten mixed target material is used for both inter- and intra-ELM simulations. The OEDGE results reveal that the inter-ELM tungsten gross erosion rate is not sensitive to the carbon fraction on the tungsten surface layer; a wider range of carbon fractions from 0.3 to 0.6 gives similar tungsten gross erosion profiles and matches the diagnostic data, which is consistent with the simple analytical model. However, the intra-ELM simulation indicates that the value of the surface carbon fraction can be as low as 0.3 to reproduce the measured tungsten gross erosion during ELMs, based on the effective ionizations/photon (S/XB) value of WI emissions. For both inter- and intra-ELM cases, carbon is predicted to dominate the tungsten erosion. However, in contrast to the inter-ELM tungsten erosion, which is dominated by locally redeposited C2+, the energetic C6+ originating from the pedestal can contribute substantial tungsten erosion in the near-separatrix region during ELMs, and the width of this C6+ dominated region exhibits a negative correlation with the heat flux density carried by ELMs.

Experimental investigation of centrifugal slurry pump casing wear handling solid-liquid mixtures

The rotating and stationary components of a centrifugal slurry pump develop complex flow field due to suspended solids in the liquid. An uneven wear of the wetted parts of the pump components was reported due to different particle impact conditions like the direct, random and directional. The present work is focused to investigate the erosive wear profile of the pump casing experimentally and its relationship with numerically simulated flow field to establish the effect of dominating factors affecting the erosion of the pump casing at different operating conditions. Experiments were conducted in a pilot plant test rig with two equi-sized sand particulate slurries at two pump speeds and two flow rates. Wear specimens (1.5 x 1.5 x 0.01 cm3) of AISI 304L steel were affixed at different locations along the centerline of the casing wall. The erosion of the specimens was determined based on the measurement of weight loss to study the wear pattern along the casing. Scanning electron microscope (SEM) images of worn out samples were also examined in each case to investigate the material failure at different locations. Further, the flow field inside the pump has been numerically simulated to correlate the particle impact condition with the measured wear. Efforts have been made to identify the dominant mechanism of erosion at different locations of the casing. It was observed that the wear at the volute tongue is contributed by both the cutting and deformation whereas, at all other locations, the material is removed due to cutting and ploughing.

Marsh edge erosion and associated carbon dynamics in coastal Louisiana: A proxy for future wetland-dominated coastlines world-wide

Coastal wetland loss through marsh edge erosion is a serious problem in Louisiana. The majority of studies on coastal land loss use aerial and satellite photographic analysis while field and site-specific measurements are limited. The aim of this study was to spatially and temporally measure coastal marsh edge erosion and investigate factors responsible for differences in erosion including shoreline orientation, soil physio-chemical properties, and wind speed and duration. A total of 33 transects across six island sites in northern Barataria Basin, Louisiana were established. Transects on shorelines facing different compass directions were measured for erosion for up to 2 years. Soils were analyzed for physiochemical properties including bulk density, organic matter, total carbon, nitrogen, and phosphorus. Bathymetric surveys were conducted to determine the extent of the erosive bay bottom profile. In addition, 14C dating of the basal organic matter (1.5–1.6 m) was conducted. Erosion rates ranged from 49.27 to 324.85 cm y-1 with a mean value of 141.69 ± 22.45 cm y−1. As expected, erosion rates were significantly different (p < 0.001) between protected and unprotected sites. The erosion rate was not correlated with wind speed (r = -0.07), weakly correlated with compass direction of shoreline (r = 0.25) and water level (r = 0.25) but strongly correlated with duration of wind (r = 0.60). Erosion rate was negatively correlated (r = -0.45) with bulk density and positively correlated with organic matter content (r = 0.42) of the top 40 cm of the soil. Over time, the marsh is eroded down to a depth of 1.5 m, which correlates to annual loss of 1.82 ± 0.29 m3 volume of marsh per meter shoreline length including a loss of organic matter (141.5 ± 22.55 kg m−1) and carbon (63.32 ± 10.09 kg m−1) previously preserved for up to 850 years. As a consequence, annual CO2 emissions for Barataria Basin were estimated to be 1.56 ± 0.26 million tCO2e y−1. Results can inform coastal managers as to the most vulnerable marshes to target restoration efforts. Due to high relative sea level rise in coastal Louisiana, these results can also be used to inform the world's stable coastlines on the relative vulnerability of their coastal marshes in the near future, due to projected eustatic sea level. Consequently, the eroding coastlines across the globe may be a significant source of CO2 emissions in near future, as millennial age stored soil carbon is released in a relatively short time, potentially overwhelming human efforts to slow rising atmospheric CO2 levels.

The influence of flow asymmetry on refractory erosion in the vacuum chamber of a RH degasser

Nozzle blockage in RH reactors is a serious operational problem since it can cause an asymmetric distribution of the steel flow in both the up-leg as well as the lower region of the vacuum chamber. This anomaly can alter the circulation rate in addition to affecting the erosion profile of the lower part of vacuum chamber refractory lining. In this study, the effect of nozzle obstruction on liquid circulation rate, wall shear stress, velocity profiles and flow pattern have been evaluated. In addition, refractory erosion in the vacuum chamber has been estimated through physical modeling and mathematical simulation results. Four blockage conditions were studied for different gas flow rates. There was a good agreement in physical and mathematical models results. Asymmetric flow was observed in vacuum chamber lower region in asymmetric blockage cases, which resulted in preferential wear on one chamber side in physical modeling experiments. The wall shear stress analysis in the vacuum chamber using a fluid dynamic model also indicates preferential erosion. When compared, refractory erosion results in physical modeling and shear stress in mathematical modeling presented good correlation.

Assessment of chemical weathering and physical erosion along a hillslope, southwest China

The chemical compositions and soil erosion characteristics of three soil profiles along a hillslope in karst area, southwest China were investigated. The material sources, element behavior and relationship between soil erosion and soil formation are discussed. Based on the 137Cs technique, the mean soil redistribution rates were found to be 11.88, −15.31 and −21.03 t ha−1 year−1 in the summit (DSD), shoulder (DSY) and toeslope (DSJ) profiles, respectively. The results show that the three profile soils are in situ weathering products of the underlying bedrocks and have inherited relationships. The Al, rare earth elements (REEs) and high field strength elements (HFSEs) contents increase with increasing clay content in DSY and DSJ profiles, indicating that these elements could be loss with clay particles via soil erosion. Coarse particles contained Si accumulates at the DSJ profile due to the migration of soil from upslope, resulting in Si enrichment. The REEs and HFSEs are mainly transported from the deposition profile DSD as solutes by chemical weathering and from the erosion profiles DSY and DSJ as particles by physical migration. The DSY profile has the thinnest soil layer and lowest clay contents, which facilitate the chemical reaction between minerals and soil water. Above all, we believe that at some intermediate soil erosion rate, that soils with the least input of fresh materials could experience the strongest chemical weathering, resulting in vast dissolution of minerals such as feldspar. These results suggested that soil texture, topographical features and vegetation coverage together affect the soil chemical weathering, physical erosion and element behaviors in karst hillslope.