Effect Of Sodium Dodecyl Sulfate Research Articles

Effect of sand content on adhesion and cohesion of municipal sludge during drying practices: The characteristics and modification

Stickiness is a phenomenon observed widely in sludge drying practices, which negatively impacts the sludge drying efficiency. This paper was aimed at evaluating the stickiness characteristics of sludge when the sand content of sludge increases during the rainy season, and carrying out stickiness modification experiments on high sand content sludge. The results indicated that the sand content was significantly positively correlated with the stickiness of sludge. During drying process, the adhesion force and cohesion force of sludge decreased with the increase of drying temperature, and the adhesion force was consistently greater than the cohesion force in every group. The sludge stickiness was reduced after ultrasonic treatment and calcium oxide modification, but the reduction effect of sodium dodecyl sulfate on sludge stickiness was not good. This study confirmed the effect of sand content on sludge stickiness, and the stickiness of sludge with high sand content can be reduced by modifier. These findings contribute to our understanding of the stickiness of sludge with high sand content in the rainy season and provide valuable insights for the optimization of sludge drying process.

Effect of sodium dodecyl sulphate on the rheological and carbon sequestration properties of cemented paste backfill with CO2 injection

Cemented paste backfill (CPB) is a technology that has a positive impact on both the environment and mining safety. In recent years, it has been widely applied and developed. To improve the carbon sequestration efficiency of CPB, air-entraining agent addition to CO2-injected CPB (CO2-CPB) has been proposed. However, the influence of air-entraining agents on the rheological and carbon sequestration properties of CO2-CPB has not been investigated to date. Therefore, sodium dodecyl sulphate (SDS), an air-entraining agent, was selected in this study, and the rheological and carbon sequestration properties of CO2-CPB added with SDS were comprehensively investigated. CO2-CPB samples with 0.0‰, 0.5‰, 1.0‰, and 1.5‰ SDS were prepared, and the rheological parameters (yield stress and viscosity) were tested after curing for 0, 0.25, 1, and 2 h. Gas content testing, microscopic analysis, and zeta potential measurements were performed. The results show that SDS addition decreased the yield stress and viscosity of CO2-CPB at 0–1 h; however, the yield stress and viscosity increased at 2 h. SDS addition significantly improved the carbon sequestration performance of CO2-CPB. The findings of this study have important implications for carbon sequestration development in CPB and solid waste utilisation.

Effective Corrosion Inhibition of Galvanic Corrosion of Cu Coupled to Au by Sodium Dodecyl Sulfate (SDS) and Polyethylene Glycol (PEG) in Acid Solution

This study investigates the effects of sodium dodecyl sulfate (SDS) and polyethylene glycol (PEG) on the galvanic corrosion behavior of copper (Cu) coupled to gold (Au) in a printed circuit board (PCB) etching solution. Galvanic corrosion tests using ZRA (zero resistance ammeter) were performed to determine the optimal SDS concentration for corrosion inhibition. The corrosion current between Cu and Au decreased significantly with the addition of SDS, from 3.26 mA/cm2 to 0.248 mA/cm2 at 4 mM SDS, achieving an inhibitor efficiency (IE) of 92.3%. However, at 15 mM SDS, the corrosion current increased, and IE decreased to 80.5%. This phenomenon is attributed to the critical micelle concentration (CMC) of SDS, where surfactant molecules aggregate and reduce surface adsorption properties. Similarly, ZRA tests were conducted to analyze the effects of PEG on galvanic corrosion. The corrosion current significantly decreased with PEG addition, achieving 98.1% IE at 1 g/L and 99.5% IE at 2 g/L. Beyond this concentration, no significant change in IE was observed, indicating saturation. Potentiodynamic polarization tests were also conducted to study the individual effects of SDS and PEG on Cu and Au. The results showed that SDS effectively inhibited Cu corrosion but had a minimal impact on Au. In contrast, PEG significantly reduced the corrosion current density for both Cu and Au, with reductions of 99.5% and 95.1%, respectively.

The effect of Sodium Dodecyl Sulfate on Polysulfone membrane for Pb (II) ions removal in an aqueous solution

The effect of Sodium Dodecyl Sulfate on Polysulfone membrane for Pb (II) ions removal in an aqueous solution

Effect of sodium dodecyl sulfate on the dielectric and electrical properties of poly (vinylidene fluoride)-zinc ferrite composites

Polymer composites comprising Poly (vinylidene fluoride) (PVDF) as a matrix, Zinc Ferrite (ZnFe2O4: ZFO) as ceramic filler and Sodium Dodecyl Sulfate (SDS) as a surface modifying agent have been synthesized through a simple solvent casting route for application in energy storage devices. The Scanning Electron Microscopic (SEM) study confirmed that the surface modification through Sodium Dodecyl Sulphate improved the dispersion of ZFO particles in the PVDF matrix. The FTIR Spectrophotometer study revealed the existence of expected functional groups in the modified composites The advantage of treatment of SDS on the composite obtained from blending of PVDF with Zinc Ferrite was investigated. The Impedance Analyzer study indicated that the composite with 1.5 wt.% Zinc Ferrite nanoparticles encapsulated by SDS exhibited the highest dielectric constant and reduced loss tangent. In addition, the experimental values of the dielectric constant were compared with some theoretical models. Further, the PE loop study showed higher remanent polarisation in the 1.5 wt.% SDS treated composite indicating that treatment of SDS on Zinc Ferrite (ZFO) can be adopted to fabricate composites for high energy storage applications.

Effects of sodium dodecyl sulfate, Sarkosyl and sodium lauroyl glutamate on the structure of proteins monitored by agarose native gel electrophoresis and circular dichroism

We have studied binding properties of three detergents, i.e., sodium dodecyl sulfate (SDS), Sarkosyl and sodium lauroyl glutamate (SLG), to model proteins based on their effects on electrophoretic mobilities of the proteins using agarose native gel electrophoresis and circular dichroism (CD). This simple technology can evaluate the dissociative properties of bound detergents from the proteins and their effects on protein structure. SDS influenced the electrophoretic mobilities of all model proteins more strongly than the other two detergents, implying a stronger inclination for protein binding and subsequent alterations in protein structure or reductions in activity, which are supported by CD analysis. On the contrary, Sarkosyl and SLG showed weaker binding and interfered less with the structure and biological activities, indicating that these detergents may be useful for protein purification and analysis. It appeared that SLG was weaker in protein binding than Sarkosyl, although the effects of these two detergents appeared to depend on the proteins.

Effect of Sodium Dodecyl Sulfate on the growth of sulfate -reducing bacteria isolated from water associated with oil production in the North Rumaila field, Basra Governorate – Iraq

Effect of Sodium Dodecyl Sulfate on the growth of sulfate -reducing bacteria isolated from water associated with oil production in the North Rumaila field, Basra Governorate – Iraq

Preparatiοn οf pοrοus hydrοxyapatite-metakaοlin geοpοlymer granules fοr adsοrptiοn applicatiοns using pοlyethylene glycοl as pοrοgen agent and sοdium dοdecyl sulfate as aniοnic surfactant.

This study investigated the elaboration of novel porous absorbent granules by mixing powdered hydroxyapatite, metakaolin, sodium metasilicate, polyethylene glycol, and sodium dodecyl sulfate (SDS), an anionic surfactant. The effect of sodium dodecyl sulfate (SDS) was then studied by introducing it as a powder to the powdered mixture or dissolved into the granulation fluid. Characterization of the granules indicated that the incorporation of SDS dissolved in the granulation fluid into the G-PEG granules improved their specific surface area (97.9 m2/g) and porosity, resulting in a synergistic increase in the adsorption of crystal violet and methylene blue dyes compared to G-PEG granules and hydroxyapatite or metakaolin geopolymer alone. Moreover, the granules exhibited satisfactory compressive strength of 0.81MPa, making them suitable for large-scale adsorption columns. Finally, the regeneratiοn prοcess οf the granules was modeled and optimized by using surface response methodology based on Box-Behnken design. The granules cοuld be regenerated fοr eight cycles under οptimum cοnditiοns οf acetic acid cοncentratiοn οf 0.72 mοl/L, a temperature οf 323K, and a cοntact time οf 173.22min, withοut a significant lοss in the adsοrptiοn capacity οr degradatiοn οf the granules. These results suggest that the pοrοus granules prepared in this study have pοtential tο be used in industrial wastewater treatment.

Effect of sodium dodecyl sulfate (SDS) on the co-deposition and frictional behavior of carbon nanotube/nickel composite layer

In this paper, the effects of sodium dodecyl sulfate (SDS) concentrations in the electroplating solution on the morphology, nucleation rate, nucleation mode, and frictional behavior of the CNT/Ni composite layers were investigated. The results showed that the electrodeposition of Ni was in a three-dimensional nucleation/growth mode. In addition, the x-ray diffraction (XRD) of the deposited layers showed that adding SDS changed the preferred growth direction of Ni from (2 0 0) to the (2 2 0) crystallographic plane. When the carbon nanotube (CNT) content was 0.1 g l−1, and the SDS content was 0.05 g l−1, the deposition potential was the most negative, increasing the number of Ni nucleation sites on the electrode and resulting in the grain size refinement of the deposited layer. It also reduced the friction coefficient of the composite simultaneously.

A novel synchronous fluorescence spectrometry combined with fluorescence sensitization for the highly sensitive and simultaneous detection of enoxacin, ofloxacin and tetracycline hydrochloride residues in wastewater

The synergistic effect of sodium dodecyl sulfate (SDS) and Mg2+ could significantly enhance the fluorescence intensity of enoxacin (ENO) at λex/λem = 269.2 nm/385.6 nm, ofloxacin (OFL) at λex/λem = 290.8 nm/466.2 nm and tetracycline hydrochloride (TCH) at λex/λem = 372.6 nm/514.8 nm. Moreover, when the wavelength difference (Δλ) was chosen 135 nm, the synchronous fluorescence spectra of the three antibiotic complexes could be well separated and the interference of the samples matrix were eliminated primely. Therefore, only one synchronous fluorescence scan was needed to simultaneously determine the three antibiotics. Based on these facts, a synchronous fluorescence spectrometry combining fluorescence sensitization for highly sensitive and selective determination of ENO, OFL and TCH residues in wastewater was developed for the first time. The experimental results showed that the concentrations of ENO, OFL and TCH in the range of 0.5–550 ng mL−1, 1–1500 ng mL−1 and 10–5500 ng mL−1 showed a good linear relationship with fluorescence intensity. The limits of detection were 0.0599 ng mL−1, 0.115 ng mL−1 and 0.151 ng mL−1, respectively. The recoveries of the actual sample were 87.50%–99.99 %, 93.00%–98.50 % and 85.70%–98.42 %, respectively. Overall, the novel synchronous fluorescence spectrometry established in the experiment has the advantages of high sensitivity, good selectivity, fast detection speed and high accuracy. It has been successfully applied to the detection of residual amounts of ENO, OFL and TCH in wastewater with satisfactory results.

Electrode Imbibition and Surfactant Interactions with Vanadium Flow Battery Electrolytes

Redox flow batteries (RFB) are a critical technology for stationary grid-scale energy storage, with potential usage with intermittent power sources, such as wind and solar. RFBs are attractive for long-duration energy storage because the anolyte and catholyte are stored separately external to the electrochemical reactor. Separating the electrolytes and the electrochemical cell decouples energy and power densities, unlike batteries that store charge in the solid-state, such as Li-ion, Pb-acid, or Ni-Cd. A standard RFB chemistry is the all-vanadium redox flow battery (VRFB), which utilizes the four oxidation states of vanadium, with V2+, V3+, V4+, and V5+. Recently our group found that adding small amounts of sodium dodecyl sulfate (SDS) to a VFRB increased the kinetics of the V2+ to V3+oxidation.Furthermore, surfactants play essential roles in battery manufacturing and operation. Surfactants can change metal oxide crystal structure, inhibit dendrite growth, limit corrosion, and prevent nanoparticle agglomeration. Surfactants are never wholly removed during manufacturing and can be present during battery operation. Therefore, it is crucial to understand how surfactants impact battery performance and their effect on the materials.This talk describes SDS's equilibrium surface properties and adsorption characteristics at the liquid−air and liquid-solid interfaces, thus providing insights into the interactions of SDS with a VFRB electrolyte. Experiments focusing on the effects of sulfuric acid and vanadium ions on SDS's equilibrium surface tension and critical micelle concentration (CMC) were completed. The Szyszkowski equation is used to calculate SDS's adsorption parameters, such as interfacial surface excess, Γsz [mol/m2], the surface excess at the saturated interface, Γ∞ [mol/m2], the minimum molecular area in the adsorption layer at the saturated interface, Amin [nm2], and the Gibbs free energy of adsorption, ΔGads [kJ/mol]. Furthermore, an examination of the spontaneous imbibition of the VFRB electrolyte with SDS into a porous carbon electrode is presented. The microstructure of porous systems, interfacial tension, and fluid−solid interactions controls the capillary-driven flow and is vital in multiphase flow in porous media. Therefore, understanding SDS's effects on the VFRB electrolyte in an electrode is critical to understanding the electrochemical reactions and molecular interactions occurring.This work was supported as part of the Breakthrough Electrolytes for Energy Storage and Systems (BEES2), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award # DE-SC0019409.

Detergent induced structural perturbations in peanut agglutinin: insights from spectroscopic and molecular dynamic simulation studies

The three dimensional structure of a protein is very important for its structure. Studies relating to protein structure have been numerous and the effect of denaturants on proteins can help understand the process of protein folding and misfolding. Detergents are important denaturants and play important roles in various fields. Here we explored the effect of sodium dodecyl sulphate (SDS) and cetyltrimethylammonium bromide (CTAB) on the structure of peanut agglutinin (PNA). The protein was purified from its natural source and impact of SDS and CTAB was studied by circular dichroism, intrinsic fluorescence, 8-anilino-1-napthalenesulfonic acid, molecular docking and molecular dynamics simulation. Pure peanut agglutinin showed a trough at 220 nm and positive ellipticity peak at 195 nm, specific for lectins. Results from the experimental and simulation studies suggest how oppositely charged detergents can interact differently and lead to varied structural perturbations in PNA. Both the surfactants induce all α protein-like circular dichroism in the protein, above its critical micelle concentrations, with significant change in accessible surface area that became more hydrophobic upon the treatment. Major interactions between the surfactants and protein, resulting in PNA conformational rearrangement, are electrostatic and van der Waals interactions. However, CTAB, a cationic surfactant, has similar effects as anionic surfactant (SDS) but at significantly very low concentration. Though the effects followed same pattern in both the surfactant treatment, i.e. above respective CMC, the surfactants were inducing all α protein-like conformation in PNA. Communicated by Ramaswamy H. Sarma

Effect of sodium dodecyl sulfate on preferential degradation of naphthalene by thermally activated persulfate: Implications for soil flushing solution reuse

Various flushing solutions that contain hydrophobic organic compounds and surfactants are generated during surfactant-enhanced soil flushing processes. How to effectively remove the target pollutants while minimizing the degradation of surfactants for reuse of the flushing solutions has become a major problem. A series of batch experiments were conducted to investigate the preferential degradation mechanisms of naphthalene by sodium dodecyl sulfate (SDS) as well as the effect of SDS concentration on the degradation efficiency using a competitive kinetic method. In addition, the effects of persulfate (PS) dosage, temperature, and pH on the degradation efficiency of naphthalene were also studied, and a prediction model based on response surface methodology (RSM) was built to optimize the preferential degradation of naphthalene. One-dimensional column flushing experiments were performed to evaluate the feasibility of reusing soil flushing solutions at the predicted PS dosage. Results show that: (i) SDS inhibited naphthalene degradation owing to competitive oxidation and micellar protection, with a decreasing degradation rate constant as SDS concentration increased. However, naphthalene was still degraded by reactive oxygen species (ROS) at a higher rate than SDS, indicating the preferential degradation of naphthalene. When the concentration of SDS increased from 5 to 10 times of critical micelle concentration (CMC; 8.2 mM), the ratio for rate constants of naphthalene to SDS (kNAP/kSDS) decreased significantly from 31.61 to 3.38, illustrating the obvious effect of SDS concentration on preferential degradation of naphthalene; (ii) The formation of single-chambered vesicles with a higher thermodynamic stability was observed at 10 CMC, compared to the spherical micelles formed at 5 CMC. The accessibility of naphthalene to ROS was greatly reduced at 10 CMC, resulting in a significant reduction in kNAP/kSDS value. Moreover, the method in which ROS attacked naphthalene in surfactant micelles varied with SDS concentration, which also impacted the preferential degradation of naphthalene; (iii) Under the optimal PS dosage predicted by the RSM model, a good reusability of SDS was observed in the soil flushing solutions after thermally activated PS oxidation, with a significant reduction on the toxic risk of soil after flushing.

Synergistic effect of sodium dodecyl sulfate (SDS) and oleic acid (OA) on gelation and lubrication performance

In this paper, it was found that with the addition of sodium dodecyl sulfate (SDS, a hydrophilic surfactant) and oleic acid (OA, a lipophilic surfactant) in a solvent with a proper composition ratio, a stable gel could be obtained via a simple ultrasonic treatment. The synergistic gelation of OA–SDS was verified in a series of solvents with different polarities, such as white oil (WO), LB-2000, n-hexane, polyalphaolefin (PAO10), and deionized water. The Fourier transform infrared (FTIR) analysis confirms that the gelation of OA–SDS is highly related to the ion exchange reaction between them. However, the xerogel of OA–SDS gelator in deionized water and WO (OSW) exhibited remarkably different morphologies, indicating that the gelation is based on different molecular assembly processes, which is governed by the orientation of the two surfactant molecules in liquid media. Further characterizations of OSW gel presented that the synergistic effect between OA and SDS not only existed in gelation, but also in enhancing the mechanical and thermal stability of WO, and endowing the OSW gel with reliable friction reduction and antiwear performances under variable working conditions. Subsequently, the lubrication mechanism was proposed based on rheological analysis and the morphological and compositional analysis of wear surfaces. This study provides a novel idea for the molecular design of lubricating gelators with wide adaptability to solvent polarity and working conditions.

Emulsion Polymerisation of Poly(Methyl Methacrylate)-Grafted-Graphene Oxide (PMMA-GO): Effect of Surfactant Concentration on Colloidal Stabilization

Graphene oxide (GO) exhibits a wide range of outstanding mechanical, electrical, and physical characteristics, and it is of substantial interest to impart such qualities onto polymeric materials such as poly (methyl methacrylate) PMMA for wider specialized functionalization. The attention of this work is on the development of emulsion polymerization procedure to prepare PMMA-GO nanocomposite and the effect of sodium dodecyl sulphate (SDS) surfactant dosages incorporated during the polymerization, on the effect of PMMA surface interactions in oil. The grafting efficiency is quantified using the Fourier-transform infrared spectroscopy (FTIR), and the effect of surfactant concentration on PMMA-GO stability is examined using UV-Visible spectroscopy, zeta potential and particle size analyses using the Malvern Zetasizer. The surfactant free emulsion has a better stabilization in terms of zeta potential analysis compared to emulsion of PMMA-GO with 0.32, and 0.4 wt. % of SDS. The polymerized PMMA-GO can be used as a model system to alter wax crystallization at low temperatures in oil and gas industries.

Biophysical assessment of amantadine and SDS surfactant mixture onto boron nitride nanotube: a molecular dynamics investigation.

The aggregation and adsorption of amantadine and sodium dodecyl sulfate on the boron nitride nanotubes in aqueous system were investigated, employing the classical molecular dynamics method. The aqueous system containing amantadine and sodium dodecyl sulfate was investigated by self-diffusion of the molecules, with particular emphasis on their center of mass mean square displacement. The radial distribution function and dipole moment measurement were used to analyze the water effect on the aggregation and molecular interaction between amantadine and sodium dodecyl sulfate in the complex. In turn, the amantadine molecules are able to develop water monolayers at the aqueous solution but show no noticeable aggregated adsorption in the fluid. In contrast, sodium dodecyl sulfate self-aggregation on the boron nitride nanotube efficiently occurs, and so the effect of sodium dodecyl sulfate on aggregated adsorption of amantadine was studied. Our results show that in the presence of sodium dodecyl sulfate at critical micelle concentration, its effect on the aggregation of amantadine was enhanced onto boron nitride nanotube compared to just pure sodium dodecyl sulfate or amantadine on boron nitride nanotube. Our simulations show a remarkable restructuring and enhanced orientation of the water molecules around sodium dodecyl sulfate and amantadine adsorbed on boron nitride nanotube. All molecular dynamics simulations were done using NAMD-2.9 package with CHARMM-36 force field. The nanotube PDB file was made by VMD with (12, 12) indexes. The nanotube atoms were considered to be fixed and periodic during the simulation process, and the ends did not cap with hydrogens. The initial PDB file of components was saved from ChemOffice software, and the webservers to obtain the charge and topology files were Reddb and Swiss Param webservers. The VMD software was used for structural visualizations and graphical analysis.

Effects of the anionactive surfactant sodium dodecyl sulfate on the adhesion of cells of the strain <i>Micrococcus luteus</i> 1-i to the surface of carbon materials

The adhesion of microorganisms on various surfaces plays a crucial role in many biotechnological processes. A widespread component of wastewater is the anion-active surfactant sodium dodecyl sulfate (SDS). Surfactants have a significant influence on all interfacial reactions, including those occurring in microbial fuel-cell technology. The work set out to study the effect of sodium dodecyl sulfate on the sorption of cells of the Micrococcus luteus 1 strain (which has electrogenic activity in microbial fuel cells) on the surface of various carbon-containing electrode materials used in biological fuel cell technology: 1) carbon tissue; 2) carbon felt; 3) crushed graphite contact trolleybus inserts (summer); 4) birch activated carbon. Using spectrophotometry and microscopy methods, the presence of sodium dodecyl sulfate in the concentration range of 10–200 mg/l was shown to increase the sorption of Micrococcus luteus 1-i cells on the surfaces of the tested carbon materials under experimental conditions. The maximum increase in sorption during 2 hours of exposure was detected when 100 mg/l of this surfactant was applied: for birch activated carbon – 21%; for carbon fabric – 26%; for carbon felt relative to the control (without surfactant) – 24%. The results demonstrate a sufficiently effective adhesion of Micrococcus luteus 1-i cells to various carbon materials, including in the presence of fairly high concentrations of sodium dodecyl sulfate, confirming the prospects of this strain for use in various types of microbial fuel cells.

Reinterpret the heterogeneous reaction of α-Fe2O3 and NO2 with 2D-COS: The role of SDS, UV and SO2

Heterogeneous reaction of mineral aerosols and atmospheric polluting gases play an important role in atmospheric chemistry. In this study, the reactions of NO2 with or without SO2 mixture gas on the surface of α-Fe2O3 particles under dry conditions were studied. The effects of sodium dodecyl sulfate (SDS) and the heterogeneous reaction under both dark and UV irradiation conditions were investigated. The infrared spectrum analyzed by the two-dimensional correlation spectroscopy (2D-COS) was used to obtain the products formation sequences. The results showed that UV irradiation can promote the production of nitrate. The 2D-COS analysis indicated SDS changed the sequence order of nitrate and nitrite species during reactions. In oxidation conditions, the final product of heterogeneous reaction of NO2 and α-Fe2O3 was monodentate nitrate. Only the heterogenous reaction of NO2 and α-Fe2O3 containing SDS (FOS) without UV light, the final product was bidentate nitrate. SDS was the catalysis agent supply and photoresist to the system. With surface active compounds, the environmental lifetime of heterogeneous reactions between trace gases and aerosols extends. Surfactants, ultraviolet light, and the types of gases involved in the reaction all have complex effects on the aerosol aging process. This study provided a reference for subsequent heterogeneous reaction studies and the formation of aerosols.

Reducing the assemblies of amyloid-beta multimers by sodium dodecyl sulfate surfactant at concentrations lower than critical micelle concentration: molecular dynamics simulation exploration

Amyloid-β peptide, the predominant proteinaceous component of senile plaques, is responsible for the incidence of Alzheimer's disease (AD), an age-associated neurodegenerative disorder. Specifically, the amyloid-β(1-42) (Aβ1-42) isoform, known for its high toxicity, is the predominant biomarker for the preliminary diagnosis of AD. The aggregation of the Aβ1-42 peptides can be affected by the components of the cellular medium through changing their structures and molecular interactions. In this study, we investigated the effect of sodium dodecyl sulfate (SDS) at much lower concentrations than the critical micelle concentration (CMC) on Aβ1-42 aggregation. For this purpose, we studied mono-, di-, tri- and tetramers of Aβ1-42 peptide in two different concentrations of SDS molecules (10 and 40 molecules) using a 300 ns molecular dynamics simulation for each system. The distance between the center of mass (COM) of Aβ1-42 peptides confirms that an increase in the number of SDS molecules decreases their aggregation probability due to greater interaction with SDS molecules. Besides, the less compactness parameter reveals the reduced aggregation probability of Aβ1-42 peptides. Based on the energetic FEL landscapes, SDS molecules with the concentration closer to the CMC are an effective inhibitory agent to prevent the formation of Aβ1-42 fibrils. Also, the aggregation direction of the peptide pairs can be predicted by determining the direction of the accumulation-deterrent forces. Communicated by Ramaswamy H. Sarma

Experimental study on the effects of ultrasonic excitation on pore structure of water-bearing coal

Coal seam water injection is one of the main coal mine dust control measures. To study the effects of ultrasonic excitation on the pore structure of water-bearing coal in depth, ultrasonic excitation experiments were conducted with varied variables including ultrasonic excitation time, ultrasonic power, and fluid pressure on coal. The effects of sodium dodecyl sulfate (SDS) treatment and ultrasonic excitation were also compared. The coal samples treated under different conditions are characterized by low-temperature nitrogen adsorption and scanning electron microscopy (SEM) respectively for the quantitative analysis of pore volume and specific surface area and qualitative analysis of surface pore and fracture structure. The results show that ultrasonic excitation can significantly increase the pore volume and specific surface area of coal and damages the inner wall surfaces of the pore to different extents, making the pore inner surfaces rougher. However, the effect of ultrasonic excitation becomes weaker after the pore volume increases to a certain extent, resulting in more uniform pore size and volume distributions. Ultrasonic excitation time affects the pores with smaller size more significantly, and there is a time threshold effect. The volume and specific surface area of large pores and fractures show limited responses (or increases) to as the excitation time increased. The energy is mainly used for the fracturing and expanding the pores with smaller size. The effect of ultrasonic excitation on pore expansion is more obvious under the fluid pressures lower than 4 MPa. High fluid pressures weaken the fracturing and expanding effect of ultrasonic excitation on the pore structure of water-bearing coal. The ultrasonic power threshold effect is also observed. Once exceeding a certain value, further increasing the ultrasonic power does not dramatically affect the pore structure of water-containing coal. Ultrasonic excitation can enlarge the primary pores and fracture and generate secondary pores and fracture in coal. In contrast, the 0.85% SDS treatment is only able to clean the primary small pores, and no new pore structures are formed.