Search

The antiwear properties of tribofilms formed on steel surfaces lubricated with various multi-component lubricants were investigated at an elevated temperature and under load-speed conditions conducive to sliding in the boundary lubrication regime. The lubricants contained base oil, reduced-level (secondary) zinc dialkyl dithiophosphate (ZDDP), and nitrogenous dispersant. The wear resistance of the tribofilms produced from different oil blends was evaluated in the context of the rate of change in the sliding track volume (wear rate for material loss) and the load-bearing capacity, chemical composition, and thickness of the tribofilms. Surface profilometry and scanning electron microscopy were used to quantify the wear performance and detect the prevailing wear mechanisms, whereas X-ray photoelectron spectroscopy elucidated the chemical composition and thickness of the tribofilms. The oil blends without ZDDP did not produce tribofilms with adequate antiwear properties, whereas the oil blends containing ZDDP and dispersant generated tribofilms with antiwear characteristics comparable to those of tribofilms produced from blends with a higher ZDDP content. Although dispersants can suspend oil contaminants and preserve the cleanness of the sliding surfaces, it was found that they can also reduce the antiwear efficacy of ZDDP. This was attributed to an additive-dispersant antagonistic behavior for surface adsorption sites affecting tribofilm chemistry and mechanical properties. Among the blends containing a mixture of ZDDP and dispersant, the best antiwear properties were demonstrated by the tribofilm produced from the blend consisting of base oil, 0.05 wt% ZDDP, and a bis-succinimide dispersant treated with ethylene carbonate. The findings of this investigation demonstrate the potential of multi-component lubricants with reduced-content ZDDP and nitrogen-based dispersant to form effective antiwear tribofilms.

In this study, a γ‐boehmite (γ‐AlOOH) – PEG/polyethylene (PE) lithium‐ion battery separator was fabricated using a dip‐coating method, with γ‐AlOOH nanowhiskers being synthesized directly through a hydrothermal process,and polyethylene glycol 10000 (PEG‐10000) was chosen for the first time as a dispersant for the γ‐AlOOH nanowhiskers in the PE coating slurry{Lee, 2014 #7}. Simultaneously, the membrane's performance was characterized, confirming the significant dispersion effect of PEG‐10000, resulting in a porosity as high as 64 % in the AlOOH‐PEG/PE, a substantial increase compared to the PE separator (40 %). The AlOOH‐PEG/PE separator maintains its structural integrity even after a 0.5 h test at 200 °C, showcasing outstanding stability and significantly improved safety. Besides, the LIB half cells assembled with the PE/AlOOH‐PEG separator exhibited remarkable performance, with a capacity of 73.9 % in power capability (at 5 C rate) and a 97.1 % discharge capacity retention rates in cycle performance (after 400 cycles, at 2 C rate). Furthermore, lithium iron phosphate (LiFePO4) batteries utilizing the AlOOH‐PEG/PE separator demonstrated significantly enhanced cycling stability and rate capacity. [ABSTRACT FROM AUTHOR]

In this paper, N-vinylpyrrolidone was copolymerized with acrylic acid and itaconic acid by free radical polymerization, and a series of polyacrylic acid-co-itaconic acid-co-N-vinylpyrrolidone (PAIN) dispersants with different pyrrolidone ligand contents were synthesized and characterized. Then, the cobalt blue nano-pigment slurry (20 wt%) was prepared through a water-based grinding method, and the optimum grinding technology was explored and determined as follows: PAIN2 as a dispersant, a dispersant dosage of 10 wt%, and a grinding time of 480 min. According to this optimum grinding technology, the prepared pigment slurry had a significantly decreased agglomeration, the D90 of which was 82 nm, and separately increased to 130 nm and 150 nm after heat storage for 3 and 7 days, exhibiting excellent heat storage stability. Additionally, its TSI value was also the lowest (1.9%), indicating good dispersion stability. The QCM and adorption capacity measuring results showed PAIN2 had a larger adsorption capacity, and the formed adsorption layer had a higher rigidity and was not easy to fall off. This was caused by both the interaction of carboxyl groups and the pyrrolidone ligand (strong coordination interaction) in PAIN2 with cobalt blue. The XPS and FT–IR measurements further proved the above-mentioned adsorption mechanism. [ABSTRACT FROM AUTHOR]

Carbon black particles possess dimensions on the nanometer or sub-nanometer scale. When utilized, these particles have a tendency to aggregate, which compromises their stability under storage conditions. To address this issue, a dispersant was prepared using cotton short fibers as raw materials through etherification and graft polymerization with acrylamide (AM) and 2-acrylamido-2-methylpropane sulfonic acid (AMPS) as raw materials. The dispersant was then used to disperse carbon black to test its dispersing performance. A response surface optimization test was utilized to ascertain the influence of AMPS monomer mass, AM monomer mass, and potassium persulfate (KPS) initiator mass on the dispersibility of carbon black during dispersant preparation, and a set of optimal preparation conditions were obtained. The dispersion stability of carbon black in water was assessed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), elemental analysis (EA), thermogravimetric analysis (TG), zeta potential analysis, high magnification scanning electron microscopy (SEM), and contact angle measurements. Results revealed that the optimum mass ratio of carboxymethyl cellulose (CMC) to AMPS to AM was 1:0.69:1.67, with the KPS initiator comprising 1.56% of the total monomer mass. By incorporating the dispersant at a concentration of 37.50%, the particle size of carbon black particles was observed to decrease from 5.350 μm to 0.255 μm, and no agglomeration of carbon black particles occurred even after 3 weeks of storage. [ABSTRACT FROM AUTHOR]

Engineering practice has shown that shield machines may become clogged in coarse-grained strata. The criteria for determining the clogging potential in coarse-grained strata were proposed. With the surface area ratio of fine to coarse particles in a soil specimen being > 30:1, the interfacial shear adhesion showed a trend of increasing first and then decreasing with an elevation in water content. However, the interfacial shear adhesion remained negligible for the soil specimen with a surface area ratio of fine to coarse particles < 25:1. Interfacial shear adhesion could be adopted for characterizing the risk of shield clogging. Thus, a critical surface area ratio of 25:1 was suggested to evaluate the possibility of clogging in coarse-grained soils. The particle gradation had no effect on the critical surface area ratio with clogging potential. The bound water between the fine particles was released after the injection of the dispersant, resulting in a reduction in the interfacial shear adhesion. The clogging potential of the soil also decreased, while the critical surface area ratio of fine to coarse particles increased. [ABSTRACT FROM AUTHOR]

Copyright of Tunnel Construction / Suidao Jianshe (Zhong-Yingwen Ban) is the property of Tunnel Construction Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We propose a new type of CNT hydrogel that has unique conductive and reversible characteristics. We found in previous studies that CNT dispersions became gelatinous without any gelators when a specific CNT was combined with a specific dispersant. This hydrogel has conductive properties derived mainly from the CNTs it contains; and even after gelation, it can be returned to a liquid state by ultrasonic irradiation. Furthermore, the liquid is gelable again. In this study, we prepared several types of CNTs and several types of dispersants, experimentally verified the possibility of gelation by combining them, and geometrically investigated the gelation mechanism to determine how this unique hydrogel is formed. As a result, we found that the experimental results and the theory examined in this study were consistent with the combination of materials that actually become hydrogels. We expect that this study will allow us to anticipate whether or not an unknown combination of CNTs and dispersants will also become gelatinous. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Petrochemical Universities / Shiyou Huagong Gaodeng Xuexiao Xuebao is the property of Journal Editorial Department Of Liaoning Shihua University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective Enhancing the heat transfer performance of heat transfer media is an effective means of efficiently exploiting geothermal resources. Numerous studies have shown that the addition of nanoscale metals or metal oxides to fluids can effectively improve the heat transfer capacity of the fluid. The physical parameters that can impact the heat transfer performance of nanofluids are type, mass fraction, size of the nanoparticle, dispersant mass fraction. Additionally, the flow rate can have an important effect on the heat transfer performance of nanofluids. Methods In this study, spherical nano-CuO and spherical nano-Al2O3 were used as nanomaterials for configuring nanofluids. The particle size of nanomaterials ranges from 20 nm to 50 nm. Sodium dodecylbenzene sulfonate was selected as the dispersant for configuring the nanofluids. Basic heat transfer experiments are performed on nanofluids by utilizing a self-constructed basic heat transfer experimental setup. The physical parameters of the nanofluids were also optimized. In addition, a self-designed experimental setup for recirculating heat exchange was established. This experimental system uses geothermal water from hydrothermal geothermal wells as the heat source. The experimental system was also utilized for field testing in a hydrothermal-type geothermal well in Yingshan County, Hubei Province. The preferred nanofluid and deionized water from the basic heat transfer experiments were subjected to on-site circulating heat transfer experiments. Comparison of the circulating heat transfer performance of nanofluids and water under actual heat source conditions in the field. The effect of the flow rate on the heat transfer performance of nanofluids and water under real heat source boundary conditions in the field is also discussed. Results The results show that (1) the heat transfer performance of CuO nanofluids is better than that of Al2O3 nanofluids. (2) There is a negative correlation between the heat transfer performance of nanofluids and the nanoparticle mass fraction. (3) The nanofluid warming efficiency was highest at a 1% mass fraction of CuO nanoparticles. The nanofluid temperature increased from 25 ℃ to 79.2 ℃ in 150 s. The nanofluid temperature increased by 4.1 ℃ more than that of deionized water in the same amount of time. Moreover, the wettability of the nanofluid-heat source interface decreases with increasing nanoparticle mass fraction. The heat transfer performance of nanofluids increases and then decreases with increasing particle size. The best heat transfer performance of the nanofluid was achieved when the nanoparticle size was 40 nm. (4) The heat transfer performance of nanofluids is negatively correlated with the dispersant mass fraction. The best heat transfer performance of the nanofluid was achieved when the dispersant mass fraction was 1%. (5) The heat transfer performance of the nanofluid is negatively correlated with the flow rate when the fluid is in laminar flow. The motion of nanoparticles is progressively more intense when the fluid is in a turbulent state. This phenomenon can effectively enhance the heat transfer performance of nanofluids. Conclusion The research results can provide a basis for the application of nanofluids in geothermal heat transfer to improve the heat transfer efficiency of geothermal systems. It also provides theoretical references for the selection of nanofluid parameters as well as fluid flow rate parameters applied to geothermal heat transfer.

Purposes The strain tolerance of Ba(Mg1/3Ta2/3)O3 (BMT) thermal barrier coating prepared by conventional atmospheric plasma spraying is low. Methods With suspension plasma spraying (SPS), BMT suspensions with different compositions are prepared by mechanical ball grinding with ethanol as the dispersion medium and polyacrylic acid (PAA), polyethyleneimine (PEI), and polyethylene glycol (PEG) as dispersants. The dispersion behavior of BMT suspension was studied through gravity sedimentation observation method, UV-Vis spectrophotometry, and Zeta potentiometry. The effects of dispersant type and content on the stability of BMT suspension were analyzed. The BMT coating was deposited by SPS, and the phase structure, surface morphology, and cross-section microstructure of the BMT coating were characterized and analyzed. Findings The results show that the adsorption of the dispersant PEI on the surface of the BMT particles improves their Zeta potential, enhances the repulsive force between particles, and provides a steric hindrance, which results the better dispersion of BMT suspension with PEI dispersant than that with PAA and PEG. In addition, the BMT suspension with PEI has a low viscosity (1.5-2 mPa·s), making it appropriate for SPS. The coating prepared by SPS essentially preserves the BMT phase structure, and shows a clear columnar-crystal microstructure. With the increases of the solid content in the suspension, the deposition efficiency of the BMT coating increase, and the volume of columnar crystals formed becomes larger, which conforms to the microstructural characteristics of high strain tolerance coatings.

In this paper we present the results of an investigation of the influence of excess energy applied through ball milling on surface hydration behavior of alumina particles manufactured by three different methods. It is shown that different hydration amount are generated due to the defects and newly generated surfaces introduced during high energy ball milling processes. And the various gibbsite/bayerite ratio of the formed hydrates are attributed to the coordination defects resulting from heat treatment during the manufacturing process. As a result, it is confirmed that the dispersant works more efficiently with particles in which hydrates are formed, and the surfaces with structures closer to gibbsite seem to respond more effectively to dispersant in slurries. [ABSTRACT FROM AUTHOR]

The development of nano-energetic materials has significantly advanced, leading to enhanced properties and novel applications in areas such as aerospace, defense, energy storage, and automobile. This research aims to engineer multi-dimensional nano-energetic material systems with precise control over energy release rates, spatial distribution, and temporal and pressure history. In this context, sol–gel processing has been explored for the manufacture of nanocomposite aluminum thermites using aerogels. The goal is to produce nano-thermites (Al/Fe2O3) with fast energy release rates that are insensitive to unintended initiation while demonstrating the potential of sol–gel-derived aerogels in terms of versatility, tailored properties, and compatibility. The findings provide insightful conclusions on the influence of factors such as secondary oxidizers (KClO3) and dispersants (n-hexane and acetone) on the reaction kinetics and the sensitivity, playing crucial roles in determining reactivity and combustion performance. In tandem, ignition systems contribute significantly in terms of a high degree of reliability and speed. However, the advantages of using nano-thermites combined with hot bridge-wire systems in terms of ignition and combustion efficiency for potential, practical applications are not well-documented in the literature. Thus, this research also highlights the practicality along with safety and simplicity of use, making nano-Al/Fe2O3-KClO3 in combination with hot bridge-wire ignition a suitable choice for experimental purposes and beyond. [ABSTRACT FROM AUTHOR]

Coal water slurries (CWSs) are considered to be a new form of fuel that can alleviate the environmental and safety issues associated with use of bulk solid fuel. However, CWSs does not always fit into existing solid fuel supply and storage chain. In this study, a novel method to control CWSs viscosity using pH-responsive thickener was proposed, offering the advantages of improved storage stability and on-demand viscosity control, thus allowing CWSs to be used as a c for a variety of applications. This study investigates the effects of additives and pH on the viscosity and storage stability of CWSs. Poloxamer 407, polynaphthalene sulfonate formaldehyde (PNSF), and a copolymer containing pigment-affinic (PA) groups were used as dispersants to lower CWSs viscosity. Xanthan gum, a modified acrylic polymer (MAP), and carbomer were used as thickeners for assessing the storage stability and fluidity of CWSs based on viscosity changes. Optimal viscosity reduction was achieved by the addition of PA. A viscosity of 7000 cP was achieved by the use of carbomer, with small amount comparable to 27.3 wt% of MAP and 22.7 wt% of Xanthan gum. Moreover, the carbomer-containing CWSs exhibited high storage stability in a 360-h stability test, retaining 84.3% of the original baseline coal content. pH-dependent viscosity changes were observed only in carbomer-containing samples. [ABSTRACT FROM AUTHOR]

Solid oxide fuel cells (SOFCs) are a green energy technology that offers a cleaner and more efficient alternative to fossil fuels. The efficiency and utility of SOFCs can be enhanced by fabricating miniaturized component structures within the fuel cell footprint. In this research work, the parallel-connected inter-digitized design of micro-single-chamber SOFCs (µ-SC-SOFCs) was fabricated by a direct-write microfabrication technique. To understand and optimize the direct-write process, the cathode electrode slurry was investigated. Initially, the effects of dispersant Triton X-100 on LSCF (La0.6Sr0.2Fe0.8Co0.2O3-δ) slurry rheology was investigated. The effect of binder decomposition on the cathode electrode lines was evaluated, and further, the optimum sintering profile was determined. Results illustrate that the optimum concentration of Triton X-100 for different slurries was around 0.2–0.4% of the LSCF solid loading. A total of 60% of solid loading slurries had high viscosities and attained stability after 300 s. In addition, 40–50% solid loading slurries had relatively lower viscosity and attainted stability after 200 s. Solid loading and binder affected not only the slurry's viscosity but also its rheology behavior. Based on the findings of this research, a slurry with 50% solid loading, 12% binder, and 0.2% dispersant was determined to be the optimal value for the fabricating of SOFCs using the direct-write method. This research work establishes guidelines for fabricating the micro-single-chamber solid oxide fuel cells by optimizing the direct-write slurry deposition process with high accuracy. [ABSTRACT FROM AUTHOR]

The primary objective of this investigation was to explore the electrochemical oxidation behavior of Sorbitan monolaurate (Span 20) under high-voltage environments. We designed and prepared working electrodes using a mixture containing Span 20 and conductive carbon black as an electron transport material. Linear sweep voltammetry (LSV) served as the technique to monitor the reactions undergone by Span 20. The oxidative products were subjected to analysis using X-ray photoelectron spectroscopy (XPS) and nuclear magnetic resonance hydrogen spectrum (1H NMR). LSV reveals the decomposition of Span 20 occurring at voltages exceeding 4.2 V, involving two distinct reactions. Further insights from XPS and 1H NMR demonstrated that Span 20 underwent a two-electron-two-proton electrochemical reaction, producing triketone and 1, 3-diketone with a hydroxyl group positioned at the 2 position. To elucidate these results, a reasoning mechanism was proposed. [ABSTRACT FROM AUTHOR]

Dispersants play a significant role in the formulation of positive battery slurry. Adding a small amount of dispersant can effectively reduce the viscosity of the slurry, which is beneficial for the production of positive batteries. A series of copolymers of N‐vinylpyrrolidone (NVP) and 2‐ethylhexyl acrylate (2‐EHA) with different molar ratios of NVP to 2‐EHA, different polymer molecular weights and different polymer structures are synthesized by dl‐methionine‐mediated reversible deactivation radical polymerization. The ability of these copolymers to disperse LiFePO4 battery positive slurry with a high solid content (57.08%) as dispersants has been evaluated. Research shows that when the ratio of NVP to 2‐EHA is 20 and the polymer molecular weight is 6000, poly(N‐vinylpyrrolidone‐ran‐2‐ethylhexyl acrylate) (NVP‐ran‐2‐EHA) exhibits the strongest dispersing ability to the slurry. This polymer can reduce the viscosity of the slurry by 43.925% and has the longest stabilization time of 3 h, which is better than poly(N‐vinylpyrrolidone) (PVP) and poly(N‐vinylpyrrolidone)‐block‐poly(2‐ethylhexyl acrylate) (PVP‐b‐PEHA) with the same molecular weight. [ABSTRACT FROM AUTHOR]

Copyright of Iron Steel Vanadium Titanium is the property of Iron Steel Vanadium Titanium Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Electron transport layer (ETL) is a crucial part for perovskite solar cells (PSCs). However, leakage current and oxygen vacancies result from little pores grown from sol‐gel method would inevitably deteriorate the performance of ETL. In contrast, thin films prepared by chemical bath deposition (CBD) could significantly restrain the little cracks. Here, SnO2 ETL are prepared by optimized CBD process, sodium citrate (SC) is explored as an auxiliary reagent to disperse ETL, thus enhances the smoothness and conductivity of the ETL, resulting in a pore‐free flat surface morphology and decreased oxygen vacancy, which is favorable for electron transport and deposition of perovskite (PVK). The PVK film fabricated on the oxygen vacancy free substrate demonstrates high quality and decreased defect density, thus effectively prevents the non‐radiative recombination of carriers. As a result, the short‐circuit current (JSC) and open circuit voltage (Voc) of the PSC devices have been obviously improved, leading to increased photoelectric conversion efficiency from 21.03% to 22.04%. Meanwhile, the long‐term and moisture stability have been promoted simultaneously. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the effect of adding flame‐retardant melamine and five different dispersants on the precipitation, foaming, mechanical, and thermal properties of flexible polyurethane foam (FPUF). Precipitation experiments were conducted to analyze the effect of dispersant on the separation of flame retardant and polyol, and the foaming characteristics of polyurethane (PU) foam after adding dispersant were analyzed. The effect of adding a dispersant on mechanical strength was characterized by measuring tensile strength, tearing strength, and hardness, and scanning electron microscopy analysis was performed to analyze morphological characteristics. Thermogravimetric analysis (TGA) was performed to analyze the thermal properties of PU foam. A horizontal flame test, limiting oxygen index test, and cone calorimeter tests were conducted to examine the flame retardancy of PU foam with flame retardant melamine and dispersant added. The dispersant ANTI‐TERRA‐U is a solution of a salt of unsaturated polyamine amides and low‐molecular acidic polyesters. And, the dispersant BYK‐220S is a solution of a low molecular weight, unsaturated acidic polycarboxylic acid polyester with a polysiloxane copolymer. The dispersants ANTI‐TERRA‐U and BYK‐220S improved the density, tensile strength, tear strength, and hardness of FPUF. TGA of the top and bottom portions of the foam showed less weight difference for samples containing dispersants, indicating better homogeneity due to improved dispersibility. Therefore, we conclude that dispersants are beneficial additives to improve the mechanical properties and dispersibility of PU foam. [ABSTRACT FROM AUTHOR]

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Environmental Science & Technology (10036504) is the property of Editorial Board of Environmental Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Sustainable construction materials and local solutions are crucial for meeting urbanisation demands in tropical regions like French Guiana. Poured earthen construction, primarily composed of local soil, offers a cost-effective and environmentally friendly alternative. To ensure good consistency for pouring, the use of dispersants to deflocculate clay particles is an effective strategy that reduces water demand while enhancing the material's physical and mechanical properties. However, the variability of soil impacts the effectiveness of dispersants and the earth's material properties. It is currently unknown how the specific properties of tropical soils can influence the mix design of poured earth and how it impacts their resulting physical and mechanical characteristics. This work examines the soil properties that could help select suitable soil for poured earth construction. Four tropical soils of French Guiana were characterised in detail and used to prepare mortars with varying amounts of water and dispersant (sodium hexametaphosphate). The consistency and compressive strength of the mortars correlated with the mineralogical and geotechnical characteristics of the soils. In particular, soils with high levels of metal oxides produced mortars with the highest compressive strength. Using a dispersant consistently increased the compressive strength and dry density of the mortars and enabled a reduction in water content. Importantly, the analysis revealed that two easily measurable soil properties, the passing at 63 µm and the pH measured in potassium chloride (pH KCl), could predict the mechanical properties of the mortars and the amount of dispersant needed. Specifically, the pH KCl correlated with the proportion of iron and aluminium oxide and showed a positive linear correlation with the compressive strength. Overall, this study identifies easily measurable soil properties, in particular the pH KCl, for selecting and designing high-performance earth materials with tropical soils. It offers promising prospects for industrialising poured earth construction.

A large amount of pulverized coal is easy to be produced in the process of hydraulic fracturing of coalbed methane reservoir. The accumulation and settlement of pulverized coal will cause serious blockage to the fractures formed by fracturing, and reduce the permeability and conductivity of fractures and affect the effect of fracturing stimulation of coalbed methane wells. Therefore, a new type of coal powder dispersant MFFS-2 was developed through a large number of laboratory experiments and combined with the reservoir characteristics of the target CBM block, and its comprehensive performance was evaluated. The experimental results show that when the mass concentration of MFFS-2 reaches 0.3%, the surface tension of water solution can be reduced to less than 25 mN/m, and the contact angle of coal surface can be reduced from 115.3° to less than 60° with good surface activity and wettability; when the suspension of coal powder is standing for 10 hours, the suspension rate of coal powder can reach more than 30% with the addition of 0.3% MFFS-2. When 0.3% MFFS-2 solution is used to displace for 2 hours, the yield of pulverized coal can reach more than 60%, which indicates that MFFS-2 has good suspension dispersion and carrying effect on pulverized coal; in addition, the damage rate of MFFS-2 to the matrix permeability of block coal core in the target area is less than 10%, and the damage degree of fracturing fluid system to the permeability of coal core is reduced after adding MFFS-2 into the active hydraulic fracturing fluid. The field fracturing operation results of coalbed methane well show that the fracturing operation of S-1 well is smooth after adding new coal powder dispersant MFFS-2, a large amount of coal powder is carried out in the backflow fluid, and the gas production is high, which achieves the expected fracturing effect. Moreover, the construction effect of the new active hydraulic fracturing fluid in the same block is significantly better than that of the conventional active hydraulic fracturing fluid.

Chemical mechanical polishing/planarization (CMP) is an essential manufacturing process in semiconductor technologies. This method combines chemical and mechanical forces to smooth the surfaces of wafers. The effectiveness of CMP relies on a carefully chosen slurry, demanding a sophisticated manufacturing technology. This technology must seamlessly integrate both chemical composition and mechanical elements, highlighting the intricate synergy required for successful semiconductor fabrication. Particularly in milling processes, if agglomerated particles due to slurry particle corrosion are present during polishing, uneven polishing, numerous fine scratches occur, leading to an increase in roughness and a deterioration in the quality of the finished surface. In this study, to overcome the issue of particle agglomeration and uneven polishing in commonly used ceria nanoparticle slurries during CMP processes, we investigated the ceria nanoparticle behavior based on styrene–maleic acid (SMA) dispersant polymer applied with three types of defoaming polymers. The investigations are expected to open up the possibility of utilizing ceria nanoparticles with applied defoaming polymer as an abrasive for advanced CMP applications. All samples were characterized by DLS (dynamic light scattering), SEM-EDX (scanning electron microscopy–energy dispersive X-ray spectroscopy), pH, conductivity, viscosity, a 10-day stability test at 60 °C, the AF4 test, and the polishing rate efficiency test. Our research demonstrates a significant improvement achieved through the use of SMA dispersant polymer, resulting in a polishing selection ratio exceeding 80 for oxide and nitride films. The G-336 defoaming polymer utilized here is expected to serve as a viable alternative in CMP processes by providing stable uniformity. [ABSTRACT FROM AUTHOR]

The industrial production of fuel ethanol is carried out by a fermentation process with yeast Saccharomyces cerevisiae commercial cell recycling resulting in excess foam formation. The present work aims to evaluate the performance of a commercial enzymatic preparation (FermaxTM) as a defoaming agent in industrial bioethanol process. The enzymatic preparation was applied concomitant with traditional chemicals. The application was carried out by pumping the enzymatic preparation into the fermentation tanks. Assay 1, in continuous mode in the treated yeast dilution tank, while assay 2, was conducted in batch mode, after sending the yeast to the fermentation tanks. The monitoring of the process was carried out by quantifying the indicators of a fermentation process. Assays 1 and 2 showed average reductions in the consumption of defoamer and dispersant of 26% and 37%, respectively. In the assay 1, the strategy of reducing the mix of ethanol production was adopted, resulting in reductions in wort flow, ethanol production, and rate of occupation of tanks. Assay 1 resulted in similar values to the traditional process without the addition of enzyme. However, in assay 2, the strategy to reduce the ethanol production mix was not adopted. In this condition, there were no significant differences in the indicators of the fermentation process between the control and enzyme periods. Assay 1 presented a net cost reduction of 15%, while assay 2 presented a net cost increase of 9%, with resources for the acquisition of chemical inputs, which totaled savings of R$ 0.40 in assay 1 and a loss of R$ 0.18 in assay 2 per cubic meter of ethanol. The decrease in the ethanol production mix was the most appropriate moment for the application of the enzyme preparation. [ABSTRACT FROM AUTHOR]

The stability and dispersion of Copper (Cu) powders in an aqueous medium impacts their performances. Thus the Cu powder suspensions were prepared by adding different stabilizers—sodium dodecyl sulfate (SDS), sodium dodecylbenzene sulfonate (SDBS), polyvinyl pyrrolidone (PVP), and hexadecyl trimethyl ammonium bromide (CTAB); the best surfactant was selected and its stability and dispersion were studied. The study systematically examined the effect of the stability of suspensions via sedimentation analysis, including solid–liquid ratio, the concentration of stabilizer, and dispersion time. The particle size, the stability of suspensions, phase composition, and microstructure of Cu powders were characterized by laser particle size analyzer, zeta potential, X-ray diffraction (XRD), transmission electron microscope (TEM), and scanning electron microscope (SEM). The results indicate that the stability of the suspension is improved with the addition of PVP due to the steric hindrance of PVP, and the growth and agglomeration of particles are retarded by the formation of a thick hydration layer with the optimizing concentrations, dispersion time, and solid–liquid ratio 10 g/L, 30 min, and 1:25, respectively. [ABSTRACT FROM AUTHOR]

High viscosity heavy oil invasion in the Tahe block have caused serious damage to the properties of the drilling fluids. To deal with this problem, the key properties of the Tahe heavy oils and those of the typical poor quality heavy oils were compared, and the change of the viscosity of the Tahe heavy oil asphaltenes in toluene solution with the concentration of the heavy oils was studied. It was found that the high viscosity of the Tahe heavy oils comes from high asphaltene content and high aromaticity. Based on this finding, two programs were prepared; one is, at the time when there is only slight heavy oil invasion, a compound additive containing appropriate dispersants and aromatic fraction can be added into the contaminated drilling fluid to disperse the heavy oils. This treatment has been best done in the 5# drilling fluid. In drilling the well TH121155X, the dispersity of the heavy oils in the solids-free drilling fluid was more than 99%. The other treatment involves the contamination of drilling fluids by large amount of heavy oils. In this treatment the heavy oils are wrapped up by wrapping agents and therefore lose their adhesiveness. The adhesiveness of the wrapped heavy oils on the surfaces of the drilling tools is minimized and the heavy oils can thus be effectively and efficiently separated out by the shale shakers. Study results show that wrapping agent BGJ-2-4 has good wrapping capacity for the treatment of heavy oils found in the well TH12471H, and the adhesion rate on the walls of mud tanks is only 0.3%. [ABSTRACT FROM AUTHOR]

In this study, the effect of a polyisobutenyl succinimide (PIB) dispersant on the tribological performances of MoS2 nanoparticles used as lubricant additives in a PAO base oil was investigated. Friction tests were conducted in boundary lubrication regime, in a steel/steel sliding contact configuration, at room temperature and at 100 °C. The tribofilms formed on the rubbed surfaces were analyzed using X-ray Photoelectron Spectroscopy (XPS) and Transmission Electron Microscopy (TEM). The results show that the dispersant used in this work prevented the agglomeration/sedimentation of the nanoparticles and strongly improved their dispersion in the base oil. Its effect on the tribological performance of the nanoparticles was found to be temperature dependent. The best friction-reducing properties were obtained at elevated temperature. It was also found that the dispersant strongly affected the tribofilm's properties (chemical composition, thickness, MoS2 flake length) and that the best reducing friction properties were obtained when the tribofilm was composed of long and well-dispersed MoS2 flakes aligned in the sliding directions. [ABSTRACT FROM AUTHOR]

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In micro-abrasive water jet polishing (MAWJP) technology, where abrasive particles serve as polishing tools, particles tend to form large clusters, leading to increased nozzle wear and diminished material polishing quality. Achieving a polishing solution with good dispersion stability is crucial for enhancing polishing accuracy and minimizing nozzle wear. Therefore, this study employed three dispersants with distinct dispersion mechanisms to examine the impact of each dispersant's concentration on the dispersion stability of the polishing solution across various abrasive concentrations. Through experimentation, the optimal dispersant type and concentration ratio of abrasive to dispersant were determined, and the effect of the selected dispersant on jet polishing performance was validated. The results of the dispersion stability experiment indicated that, in comparison to Na(PO3)6 and polyethylene glycol (PEG), the polishing solution containing 1.0–2.0 wt% phosphoric ester compounds exhibited a more stable dispersion effect (zeta potential < −50 mV) and superior dispersibility, characterized by a smaller average particle size. Furthermore, K9 optical glass was subjected to fixed-point and local polishing using phosphoric ester compounds as the dispersant. The fixed-point polishing experiment revealed that, at a dispersant concentration of 1.0 wt% and an abrasive concentration of 20 wt%, a smooth and symmetrical material removal profile could be achieved. In the local polishing experiment, the reduction rate of the root mean square of the surface roughness (RMS) increased from 54.33% to 82.24%, and the reduction rate of peak-to-valley height difference in surface (PV) increased from 38.84% to 68.97%. In conclusion, the incorporation of a dispersant proves effective in enhancing the dispersion stability of the polishing solution and dispersibility of the abrasive particles, thereby improving the surface quality of the materials in MAWJP. [ABSTRACT FROM AUTHOR]

Polycarboxylic acid dispersant has the advantages of good dispersion performance and environmental protection, and has a good application prospect in oil well cement. However, the current polycarboxylic acid dispersant has poor temperature resistance, which limits its application in high-temperature formation cementing. In this study, a polycarboxylic acid dispersant (NLPC) that can be applied to high-temperature cementing was synthesized by free radical copolymerization of monomer isoprenol polyoxyethylene ether, maleic acid, 2-acrylamido-2-methylpropanesulfonic acid and N-vinyl-2-pyrrolidone. The structure of NLPC was characterized by Fourier transform infrared spectroscopy, gel permeation chromatography and 1H nuclear magnetic resonance spectroscopy. The effects of NLPC on the fluidity, rheological properties, thickening time and mechanical strength of cement slurry at different temperatures were tested, and compared with the traditional sulfonated acetone-formaldehyde polycondensate (SAF) dispersant. The mechanism of dispersant and its effect on cement hydration behavior were systematically studied by total organic carbon, Zeta potential, particle size analysis, thermogravimetric analysis and X-ray diffraction analysis. The effect of dispersant on the microstructure of hardened cement was analyzed by scanning electron microscopy. The results show that NLPC has excellent high temperature dispersion performance. At 150 °C, NLPC can significantly reduce the consistency coefficient of cement slurry, increase the fluidity index of cement slurry, significantly improve the rheological properties of cement slurry, and the paste has excellent thickening performance, and the initial consistency is lower than SAF. In addition, due to the good dispersion of cement particles by NLPC, the early mechanical strength of cement stone after solidification is also improved. The mechanism analysis shows that NLPC improves the dispersion performance of oil well cement slurry mainly through electrostatic repulsion and steric hindrance effect. In a word, NLPC overcomes the shortcomings of low efficiency and heavy pollution of SAF dispersant and the low applicable temperature of current polycarboxylic acid dispersant products, which is of great significance to ensure the smooth operation of high temperature deep well cementing and improve the cementing quality. Highlights: NLPC improves the temperature resistance of polycarboxylic dispersant. NLPC improves the rheological properties of oil well cement slurry at high temperature. The mechanism of NLPC is steric hindrance and electrostatic repulsion. NLPC has good compatibility with other oil well cement additives and has no adverse effect on the implementation of cementing engineering. [ABSTRACT FROM AUTHOR]

The current work focuses on experimental studies using Mesua Ferrea biodiesel (BD20) and Cr2O3 nanoparticles in a diesel engine. In different concentrations, 60, 80, and 100 mg/L Cr2O3 nanoparticles were mixed. In addition, the dispersant (QPAN80) and surfactant (CTAB) were used to change the surface of the Cr2O3 nanoparticle (at a 1:1 ratio). The compression ratios were varied such as; 16.5:1, 17.5:1, and 18.5:1, respectively. Using a mechanical agitator and a probe sonicator, the nanofuel was produced by inserting the surface modified Cr2O3 nanoparticles into BD20. The combustion characteristics of nanoparticles added to BD20, such as cylinder pressure (CP) and net heat release rate (NHRR) have improved greatly over normal diesel. However, nanofuels improved performance in terms of brake specific fuel consumption (BSFC) and brake thermal efficiency (BTE). Together with NOx, the emission characteristics (CO, UHC, and smoke) were reduced momentously. Eventually, a good trend in performance, combustion, and emissions were seen as the compression ratio increased. The dispersant added nanoparticles in BD20 has shown good outcomes than the surfactant added nanoparticles and base nanoparticles. The BD20 + Cr2O3 80 mg/L + DSP 80 mg/L had the best results of all the test samples. At CR 18.5:1, the BTE, BSFC, CP, and NHRR were 34.52%, 0.342 kg/kWh, 65.52 bar, and 88.79 J/oCA, respectively, whereas CO, UHC, smoke opacity, and NOx were, 0.092%, 35 ppm, 20.26%, and 1249 ppm, respectively. [ABSTRACT FROM AUTHOR]

The 2010 Deepwater Horizon (DwH) Oil spill released an enormous volume of oil into the Gulf of Mexico (GoM), prompting the widespread use of chemical dispersants like Corexit® EC9500A. The ecological consequences of this treatment, especially when combined with natural factors such as sunlight, remain unexplored in the context of marine bacterial communities' dynamics. To address this knowledge gap, our study employed a unique metaproteomic approach, investigating the combined effects of sunlight, crude Macondo surrogate oil, and Corexit on GoM microbiome across different mesocosms. Exposure to oil and/or Corexit caused a marked change in community composition, with a decrease in taxonomic diversity relative to controls in only 24 hours. Hydrocarbon (HC) degraders, particularly those more tolerant to Corexit and phototoxic properties of crude oil and/or Corexit, proliferated at the expense of more sensitive taxa. Solar radiation exacerbated these effects in most taxa. We demonstrated that sunlight increased the dispersant's toxicity, impacting on community structure and functioning. These functional changes were primarily directed by oxidative stress with upregulated proteins and enzymes involved in protein turnover, general stress response, DNA replication and repair, chromosome condensation, and cell division. These factors were more abundant in chemically treated conditions, especially in the presence of Corexit compared to controls. Oil treatment significantly enhanced the relative abundance of Alteromonas, an oil-degrading Gammaproteobacteria. In combined oil-Corexit treatments, the majority of identified protein functions were assigned to Alteromonas, with strongly expressed proteins involved in membrane transport, motility, carbon and amino acid metabolism and cellular defense mechanisms. Marinomonas, one of the most active genera in dark conditions, was absent from the light treatment. Numerous metabolic pathways and HC-degrading genes provided insights into bacterial community adaptation to oil spills. Key enzymes of the glyoxylate bypass, enriched in contaminant-containing treatments, were predominantly associated with Rhodobacterales and Alteromonadales. Several proteins related to outer membrane transport, photosynthesis, and nutrient metabolisms were characterized, allowing predictions of the various treatments on biogeochemical cycles. The study also presents novel perspectives for future oil spill clean-up processes. [ABSTRACT FROM AUTHOR]

A lignin modified salt-resistant branched high-performance water reducer was prepared via free radical polymerization. The water-reducing agent was identified through its NMR spectrum, elemental analysis, Fourier transform infrared analysis, thermal gravimetric analysis, and scanning electron microscopy. The experiment conducted on cement paste demonstrates that the water-reducing efficiency can reach a maximum of 44%. Additionally, the significant spatial steric hindrance of the application enhances the dispersal capability of the water-reducing agent, resulting in effective water reduction and reduced viscosity. In addition, its compressive strength is the highest after 3-day curing and 3-, 7-, 28-day standard curing, and it has the best overall performance both in water and saline water prepared systems. The application in oil cement slurry shows that it exhibits a good dispersibility in fresh water, saline water, and substitute ocean water. In the Halfaya and Missan Oilfields of Iraq, BHPWR was used in a slurry with a density of 2.28 g/cm3 for casing the salt paste layer of five wells. The cementing results exceeded expectations with 100% qualified including over 85% excellent. [ABSTRACT FROM AUTHOR]

Porous honeycomb mullite ceramics were controllably fabricated in-situ using stereolithography 3D printing. The effects of the dispersant type and content on the rheological behavior of the mullite precursor slurry were investigated. Additionally, the influence of the debinding atmosphere (air and argon) on the quality of the samples and formation of cracks was also studied. The results indicated that oleic acid (OA), 3-glycidoxypropylthrimethoxysilane (KH560), and disperbyk (BYK111) displayed the capability to create low-viscosity and highly stable slurries. Among these KH560 was proved to be the most effective. The mullite precursor slurry containing 4 wt% KH560 dispersants exhibited a shear thinning behavior. It displayed a viscosity of 0.26 Pa·s at a shear rate of 30 s−1. The mullite ceramic parts displayed good a dimensional resolution at an exposure dose of 5.47 mJ/cm2. During the debinding process, the printed parts were susceptible to cracking and deformation in air, but remained devoid of defects in argon. When the samples were sintered at 1600 °C, the corundum phase transformed almost completely into the mullite phase. The linear shrinkage values were 5.81%, 6.33%, and 10.26% in the O-X, O–Y and O-Z directions, respectively. [ABSTRACT FROM AUTHOR]

In this study, an inorganic retarder and a synthesized dispersant (based on PCE) were used to improve the retention and workability of alkali-activated ground granulated blast furnace slag (GGBFS), with NaOH as the sole activator. The objective of the study was to formulate pumpable concrete mixtures with workable time of more than 90 min. The prolonged retention in slump was attained by the addition of the retarder. The effect of the dispersants, synthesized with different monomer to macromonomer ratios, on the workability of the paste was investigated by analyzing the fundamental rheological parameters. The addition of dispersant reduced the initial storage modulus and improved the workability of the alkali-activated paste mixtures. The interaction between the dispersant and NaOH-activated GGBFS systems was investigated by means of adsorption studies and zeta potential measurements. The dispersing ability and the amount adsorbed on GGBFS increased with an increase in the anionic charge of the dispersant. Zeta potential measurements suggested that the dispersion mechanism is primarily due to steric hindrance. Concrete mixtures of compressive strength in the range of ordinary concrete with pumpable workability for 90 and 120 min were achieved with the addition of both retarder and dispersant. The study concludes that a retarder is necessary to prolong the workable times, whereas a dispersant with a higher anionic charge is required to improve the workability of sodium hydroxide-activated GGBFS mixtures.

While tunnel boring machines (TBMs) tunneling in clayey strata, the adhered excavated soil on the cutterhead and cutting tools tends to form mudcake after compaction and consolidation. Mudcake can obstruct the cutterhead openings and rendering the cutting tools ineffective, leads to a substantial reduction in advance rate. Dispersants are recognized as an effective method for the disintegration of mudcakes. A novel set of equipment, comprising a mudcake compression device and a mudcake disintegration apparatus, is developed for assessing mudcake disintegration properties. The results showed that mudcakes underwent a tripartite disintegration process in water, including an initial stage, a rapid disintegration stage, and a stable stage. In the initial stage, the mudcakes absorbed water before disintegration, resulting in marginal changes in the weight of the disintegrated mudcakes. In the rapid disintegration stage, the weight of the disintegrated mudcakes increased quickly. During the stable stage, the weight of the disintegrated mudcakes remained relatively constant. The submersion of mudcakes in a dispersant solution substantially increased the rate of disintegration. Greater dispersant concentration corresponded to an increase in the disintegration rate. No weight gain was observed in mudcakes during the initial disintegration stage. When mudcakes disintegrated in a bentonite slurry, the weight of the disintegrated mudcakes initially decreased and then stabilized. The weight of the disintegrated mudcakes turned negative, indicating an increase in the weight of mudcakes. This suggested that bentonite significantly hindered mudcake disintegration.

For enhancing the physical properties of water-based acrylic resin coating, a green modified water-based nano-alumina dispersion was successfully prepared by regulating mass fraction of anti-sedimentation dispersant under the condition of ultrasonication. Subsequently, the water-based nano alumina dispersion was characterized, and the physical properties of commercial water-based acrylic resin composite coating mixed with the dispersion were tested. Results showed that under the conditions of a dispersant mass fraction of 0.50% and an ultrasonic dispersion time of 0.5 h, the storage stability time of the prepared water-based nano-alumina dispersion was greater than 90 d. Besides, after adding 4%(mass fraction) water-based nano-alumina dispersion to commercially available water-based acrylic resin coatings, the wear-resistant rotation number of the as-obtained coating increased from less than 5 r to more than 15 r, and the scratch resistance load increased from 1.10 kg to 2.00 kg.

In this paper, N-vinylpyrrolidone was copolymerized with acrylic acid and itaconic acid by free radical polymerization, and a series of polyacrylic acid-co-itaconic acid-co-N-vinylpyrrolidone (PAIN) dispersants with different pyrrolidone ligand contents were synthesized and characterized. Then, the cobalt blue nano-pigment slurry (20 wt%) was prepared through a water-based grinding method, and the optimum grinding technology was explored and determined as follows: PAIN2 as a dispersant, a dispersant dosage of 10 wt%, and a grinding time of 480 min. According to this optimum grinding technology, the prepared pigment slurry had a significantly decreased agglomeration, the D90 of which was 82 nm, and separately increased to 130 nm and 150 nm after heat storage for 3 and 7 days, exhibiting excellent heat storage stability. Additionally, its TSI value was also the lowest (1.9%), indicating good dispersion stability. The QCM and adorption capacity measuring results showed PAIN2 had a larger adsorption capacity, and the formed adsorption layer had a higher rigidity and was not easy to fall off. This was caused by both the interaction of carboxyl groups and the pyrrolidone ligand (strong coordination interaction) in PAIN2 with cobalt blue. The XPS and FT–IR measurements further proved the above-mentioned adsorption mechanism.

Carbon black particles possess dimensions on the nanometer or sub-nanometer scale. When utilized, these particles have a tendency to aggregate, which compromises their stability under storage conditions. To address this issue, a dispersant was prepared using cotton short fibers as raw materials through etherification and graft polymerization with acrylamide (AM) and 2-acrylamido-2-methylpropane sulfonic acid (AMPS) as raw materials. The dispersant was then used to disperse carbon black to test its dispersing performance. A response surface optimization test was utilized to ascertain the influence of AMPS monomer mass, AM monomer mass, and potassium persulfate (KPS) initiator mass on the dispersibility of carbon black during dispersant preparation, and a set of optimal preparation conditions were obtained. The dispersion stability of carbon black in water was assessed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), elemental analysis (EA), thermogravimetric analysis (TG), zeta potential analysis, high magnification scanning electron microscopy (SEM), and contact angle measurements. Results revealed that the optimum mass ratio of carboxymethyl cellulose (CMC) to AMPS to AM was 1:0.69:1.67, with the KPS initiator comprising 1.56% of the total monomer mass. By incorporating the dispersant at a concentration of 37.50%, the particle size of carbon black particles was observed to decrease from 5.350 μm to 0.255 μm, and no agglomeration of carbon black particles occurred even after 3 weeks of storage.

We propose a new type of CNT hydrogel that has unique conductive and reversible characteristics. We found in previous studies that CNT dispersions became gelatinous without any gelators when a specific CNT was combined with a specific dispersant. This hydrogel has conductive properties derived mainly from the CNTs it contains; and even after gelation, it can be returned to a liquid state by ultrasonic irradiation. Furthermore, the liquid is gelable again. In this study, we prepared several types of CNTs and several types of dispersants, experimentally verified the possibility of gelation by combining them, and geometrically investigated the gelation mechanism to determine how this unique hydrogel is formed. As a result, we found that the experimental results and the theory examined in this study were consistent with the combination of materials that actually become hydrogels. We expect that this study will allow us to anticipate whether or not an unknown combination of CNTs and dispersants will also become gelatinous.

This article describes a comparative evaluation of effectiveness of certain commercial dispersants (Finasol OSR 52 (France) and Slickgone NS and Slickgone EW (Great Britain)) for spill response of three crude oils produced in Russia and characterized by different physicochemical properties (extra light, heavy, and bituminous) in waters of various salinity. The evaluation has been based on an adapted version of ASTM F2059-17 "Standard Test Method for Laboratory Oil Spill Dispersant Effectiveness Using the Swirling Flask" (the so called SFT test). The conventional lower limits of dispersant effectiveness have been determined using a low energy procedure. Comparative tests of dispersant effectiveness have been performed at the highest dispersant-to-oil ratio of 1 : 10 allowed in the Russian Federation (according to STO 318.4.02-2005 "Rules of Dispersant Application for Oil Spill Response"), water temperature 20°C, and water salinity of 0, 5, 10, 20, and 35‰. It has been revealed that the considered dispersants have low effectiveness for dispersion of the tested oil samples at water salinity of 35‰. A general trend of increase in dispersant effectiveness with decrease in water salinity is demonstrated. It has been established that all considered dispersants are not suitable for application throughout the analyzed salinity range in the case of spill of bituminous oil with high content of asphaltenes and polar compounds. The limits of dispersant application have been determined for all dispersants as a function of water salinity. The effectiveness of 45%, legally validated in the United States and Mexico, has been selected as the threshold value. It has been proved that, as a consequence of nonuniversality of dispersant action, it is recommended to carry out preliminary experimental examination of their effectiveness using a sample of spilled oil under climatic and hydrochemical conditions corresponding to the potential region of application. [ABSTRACT FROM AUTHOR]

The temperature enduring capacity of turbine blades determines the thrust-weight ratio of aero-engines. The heat dissipation efficiency of blades is improved mainly through designing complex internal cooling channel. As a transitional component of blade preparation, the shape of ceramic cores has become gradually complex. The traditional process is difficult to meet the preparation requirements of ceramic core with complex structure due to the limitation of mold. Stereolithography 3D printing provides a feasible technology for the preparation of ceramic cores with complex structures. The key to high-performance ceramic core via the stereolithography 3D printing lies in the prepare ceramic slurry with high solid loading, low viscosity and uniform stability. Choosing suitable dispersant is an effective way to prepare above standard slurry. In this study, the effects of single and dual dispersants on the rheological properties of ceramic slurry were systematically investigated. The action mechanism of the dispersant was analyzed. The functional relationship between solid loading and viscosity was elucidated. The silicon-based ceramic core slurry with 70 vol% solid loading and viscosity of 10520 mPa s (12.6 s−1) was obtained. Through optimizing printing parameters, the complex structure silicon-based ceramic core was fabricated. The influence of solid loading on the microstructure and physical properties of the ceramic core was investigated. The results show that with the increase of solid loading, the shrinkage of ceramic core lowers and the flexural strength of ceramic core strengthens. The successfully preparation of complex structure ceramic core based on high solid loading slurry promotes the extensively implemented of stereolithography 3D printing technology in the field of ceramic core. [Display omitted] [ABSTRACT FROM AUTHOR]

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

PU foams are widely used in the automobile industry not only for their lightweight properties, but also as sound-absorbing and seat cushioning materials. The effects of particles on the sound absorption properties of PU composite foams were investigated. PU foams containing 3 wt% melamine particles showed excellent sound absorption properties. However, when the particle content exceeded 3 wt%, particle agglomeration occurred, leading to reduced sound absorption. A dispersant was added during the fabrication process to improve the interfacial compatibility between the PU matrix and melamine particles, resulting in a well-developed cavity and pore structure. The sound absorption characteristics of the PU composite foams were significantly improved in the frequency range below 2,000 Hz. Our study highlights the importance of adjusting the concentration of particles and optimizing the cavity and pore structure of the material for achieving better sound absorption properties in PU composite foams. [ABSTRACT FROM AUTHOR]

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The application of polymer flocculants plays a pivotal role in the slurry separation process of shields, and the dispersant used for treating cutter mud cakes can significantly impact the effectiveness of polymer flocculants, potentially leading to reduced efficiency in slurry separation. Experiments were conducted to select appropriate flocculants and investigate the influence of dispersants on flocculant effectiveness, aiming to assess the effect of flocculants and explore the relationships and mechanisms governing their influence. Changes in the patterns of slurry flocculation were revealed in terms of flocculation-driven precipitation and vacuum-filtration effects. The purpose of this article is to provide a reference for the field application of polymer flocculants in the shield field. The conclusions are as follows. Inorganic flocculants containing 0.5% polyaluminum chloride (PAC) exhibit the most effective flocculation, demonstrating strong charge neutralization action. Organic flocculants containing 0.1% cationic polyacrylamides (CPAM) exhibit the most effective flocculation, demonstrating strong bridging and net capture effects. The dispersant sodium hexametaphosphate (SHMP) can significantly weaken the charge-neutralizing action of flocculants and slightly enhance bridging and net capture effects. SHMP can impede the flocculation of slurry with PAC. For CPAM, SHMP can enhance the flocculation of slurry at a low mass fraction (0.1% and 0.3%), while SHMP can significantly hinder flocculation at a high mass fraction (0.5% and 1%). A low mass fraction of SHMP reduced slurry viscosity to 246.3 mPa.s and enhanced vacuum filtration, while a high mass fraction of SHMP increased slurry viscosity to 667.2 mPa.s and hindered vacuum filtration. In conclusion, while dispersants reduce the effectiveness of inorganic flocculants at any mass fraction, a small number of dispersants enhances the performance of organic flocculants; thus, the organic flocculant CPAM is recommended for slurry separation. [ABSTRACT FROM AUTHOR]

As a novel form of carboxylate comb‐like copolymers, SAM‐(m)PEG was prepared by polymerizing styrene (S), acrylic (A), and maleic anhydride (M) to obtain a random copolymer labeled SAM. SAM was then esterified using either polyethylene glycol (PEG) or methyl PEG (mPEG), a waterborne polymer dispersant for dispersing and stabilizing C.I. Pigment Yellow 180 (PY 180). The structures of SAM‐(m)PEG and the ground suspension of PY 180 were characterized by Fourier transform infrared (FT‐IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, scanning electron microscopy (SEM), a nanoparticle size analysis, and viscometry. The effects of different branch chains, synthetic formulas, and grinding conditions on the dispersibility of SAM‐(m)PEG were evaluated. In addition, the optical properties of the pigments were investigated after ultrafine grinding. The adsorption mechanism between the SAM‐(m)PEG dispersants and PY 180 particles is also discussed. SAM‐PEG6002 outperformed the other SAM‐(m)PEG dispersants owing to its excellent dispersion and stability. When used as the dispersant, the average particle size (Z‐average) of PY 180 after grinding was 264.6 nm, and the particle size distribution became narrow (PDI=0.089). Moreover, SAM‐PEG6002 effectively maintained the color performance of the pigment, and the product was successfully applied to the pigment coating. Therefore, SAM‐PEG6002 is an effective waterborne polymer dispersant for organic pigments. [ABSTRACT FROM AUTHOR]