Uniform Suspension Research Articles

Preparation of Superhydrophobic Magnetic Polyurethane Sponge for Removing Oil Pollutants from Water

The superhydrophobic magnetic sponge were prepared by Fe3O4 nanoparticals and stearic acid which were coated on the surface of polyurethane sponge. The preparation process of the superhydrophobic materials are prepared under mild, low-cost and environment-friendly conditions. pieces of PU sponges were decorated immersed in a ethanol solution which uniform suspension Fe3O4 nanoparticles ethanol by ultrasonication, and the obtained PU sponges were modified with stearic acid. The Fe3O4 and stearic acid were coated onto the skeleton surface of the sponge, which make the as-prepared sponge possess magnetic and hierarchically microstructure. The high elasticity sponge can through the simple squeeze realize oil recovery. After 5 cycles, the as-prepared sponge retains excellent absorption properties. The superhydrophobic magnetic polyurethane sponge has great potential in industrial oil separation and oil spill recovery in future.

Hydrodynamics of activated char in a novel multistage circulating fluidized bed for dry desulfurization

A novel multistage fluidized bed was proposed to improve the desulfurization efficiency of activated char in a circulating fluidized bed–flue gas desulfurization process. The hydrodynamics of gas–solid flow in the multistage fluidized bed was experimentally studied. Results showed that the overall pressure drop of the bed had a good linear relationship with the ratio of the superficial gas velocity and the solid circulation rate. Compared with the conventional fluidized bed for desulfurization, a relatively uniform upward flow over a cross section was observed in the middle conveying section of the multistage fluidized bed. Intensive gas–solid interaction in the expanding section of the multistage fluidized bed was confirmed. In addition, a uniform suspension upward flow with minimal solid backmixing at the upper portion of the expanding section was observed under limited operating conditions. Finally, the gas–solid flow structure in the expanding section of the multistage fluidized bed was depicted.

Surface-conductive UHMWPE fibres via in situ reduction and deposition of graphene oxide

Surface-conductive ultra-high molecular weight polyethylene (UHMWPE) fibres were prepared via in situ reduction and deposition of graphene oxide (GO). GO was dispersed in water to form a uniform and stable suspension. Subsequently, GO was chemically reduced into rGO and spontaneously deposited onto gel-spun, ultra-drawn UHMWPE fibres. The UHMWPE was coated with polydopamine (PDA), emulating the surface coating in mussels, prior to the rGO deposition to improve the bonding between rGO and the fibre surface. Characterizations using SEM, EDX, FTIR and XPS confirmed the effectiveness of the PDA coating and rGO deposition and the covalent bonding between PDA and rGO. The electrical resistance of UHMWPE-PDA-rGO decreased monotonically with increasing GO percentage in the suspension and deposition cycle. The UHMWPE-PDA-rGO exhibited an electrical resistance of 105 Ω/cm, whereas UHMWPE and UHMWPE-PDA showed a resistivity of >1012 Ω/cm. Using Ag deposited UHMWPE-PDA as the benchmark, UHMWPE-PDA-rGO was superior in durability, conductivity and retention of ultrahigh tensile properties. Analysis using the TGA data and linear density confirmed the partial reduction of GO during processing. Furthermore, a plausible log-log linear relationship was revealed between the resistance and the weight ratio of UHMWPE-PDA + GTGA and pure UHMWPE-PDA (χ), which tentatively explained the deposition mechanisms.

Thermo-physical properties of cooling water-based nanofluids containing TiO2 nanoparticles modified by Ag elementary substance for crystallizer cooling system

For enhancing the thermal performance of the crystallizer cooling water and also to achieve stable and uniform suspension, TiO2 nanoparticle modified with (3-mercaptopropyl) triethoxysilane (MPS) coupled Ag nanoparticle was added to the cooling water. Other than the investigation on the thermal performance, rheological properties were also investigated, both prior and post nanoparticle addition. The XRD, FT-IR spectrometer and TEM were used to study the morphology and properties of TiO2-Ag nanoparticles. Simultaneously, UV–vis absorption spectrometer and zeta potential were used to confirm the stability of the prepared nanofluids. Furthermore, the temperature dependent thermal conductivity study with different volume fractions carried out for TiO2-Ag cooling water-based nanofluids reported considerable enhancement. Based on researching rheological property, TiO2-Ag nanofluids are found to be promising to the research of crystallization cooling water. Moreover, experiment results have been compared with classical models and new formulas were rebuilt for thermal conductivity and viscosity. This study will play a significant role in the study of the heat transfer of crystallizer cooling water.

Distribusi Sedimen Permukaan Dasar Laut Perairan Sumba, Nusa Tenggara Timur

<strong>Subsurface sediment distribution in the Sumba Waters, East Nusa Tenggara.</strong> Marine geological survey of the Ekspedisi Widya Nusantara 2016 was conducted in the Sumba Waters on 4 to 26 August 2016 using Baruna Jaya VIII research vessel. The aim of this survey was to reveal the type and characteristics of the subsurface sediments of the Sumba Waters. A total of 13 samples were taken from the different depth in the subsurface bottom of the sea using grabbing methode with box corer. Grain size analysis were conducted using Mastersizer 2000 to understand the characteristics and the sediment type distribution. In general, the type of the subsurface sediment in the Sumba Waters is ranging from medium to very coarse sandy silt. Distribution of the subsurface sediments is correlated to depths. Grain size of the sediments in the Sumba Strait is coarser than in the western and southern of Sumba Island that directly connected to the Indian Ocean. Distribution of the subsurface sediment showing that the sediment, which are distributed further away from the coast is poorly sorted. The deposition of the subsurface-sea sediment is interpreted to represent a calm, and slow sedimentation mechanism under uniform suspension process.

EDTA-modified PANI/SWNTs nanocomposite for differential pulse voltammetry based determination of Cu(II) ions

Differential pulse voltammetry (DPV) based electrochemical sensor dedicated for the determination of Cu(II) ion concentration is reported in this research. Sensor was based on electrochemically synthesized polyaniline (PANI) and single walled carbon nanotubes (SWNTs) nanocomposite (PANI/SWNTs), which was additionally functionalized by ethylenediaminetetraacetic acid (EDTA) in order to get structure (EDTA-PANI/SWNTs) with advanced selectivity towards Cu(II) ion. Synthesis of PANI/SWNTs nanocomposite was performed by potential cycling, dodecyl benzene sulphonic acid sodium salt (DBSA) was used as a surfactant during the synthesis of PANI/SWNTs nanocomposite to get a uniform suspension of SWNTs at room temperature. In the next step, PANI/SWNTs nanocomposite was further modified by the EDTA solution containing 1-ethyl-3(3-(dimethylamino)propyl)-carbodiimide (EDC) as activating agent, which is activating carboxyl groups, utilizing dip coating technique at room temperature. Differential pulse voltammetry (DPV) technique was applied for the electrochemical detection of Cu(II) ion. DPV based response of EDTA-PANI/SWNTs structure towards Cu(II) ion was investigated. Analytical signals reveal that EDTA-PANI/SWNTs structure is suitable for selective determination of Cu(II) ion in the presence of interfering Pb(II), Cd(II), Ni(II) and Co(II) ions.

Design and criticality analysis of colloidal slurry nuclear reactors

A novel nuclear reactor concept is presented in this paper which can sustain the controlled fission reaction and has an innovative mechanism of reactivity control. The concept of this reactor is based on the stability of colloidal suspensions. These suspensions consist of colloidal fuel particles suspended in a moderator with a controllable separation distance. The packing factor of the colloidal suspension can be controlled by slightly modifying the ionic concentration of the suspension medium, effectively controlling the criticality of the reactor. Based on local average separation distance between particles, thermalization of neutrons can be varied and can be used to manipulate neutron multiplication factor k∞. Numerical calculations are performed with the help of MCNP software to obtain optimal configuration of critical assemblies. For the numerical case studies presented in this paper, uranium dioxide (UO2) fuel particles with size ⩾10μm in different liquid solvents are considered. The fuel particles are simulated as hard spheres packed in Bravais lattice structures within the solvent medium. Simulations involve neutron interactions of a uniform colloidal suspension of spherical fuel elements of diameters 5cm–0.001cm. The homogeneous fuel equivalence was found to occur for particles sized below 0.010cm diameter. Criticality curves are generated for fuel particle configurations with varying particle density, confirming fuel configurations can be controlled by only modifying particle packing factor. Additional criticality curves are generated for various cylindrical geometries of fuel suspension vessels with modular form factors. Triethylene glycol is substituted as a moderator and suspension fluid with higher boiling point as compared to water. The type of moderator or solvent does not have any significant impact on criticality performance.

Flow-induced gelation of microfiber suspensions

The flow behavior of fiber suspensions has been studied extensively, especially in the limit of dilute concentrations and rigid fibers; at the other extreme, however, where the suspensions are concentrated and the fibers are highly flexible, much less is understood about the flow properties. We use a microfluidic method to produce uniform concentrated suspensions of high aspect ratio, flexible microfibers, and we demonstrate the shear thickening and gelling behavior of such microfiber suspensions, which, to the best of our knowledge, has not been reported previously. By rheological means, we show that flowing the suspension triggers the irreversible formation of topological entanglements of the fibers resulting in an entangled water-filled network. This phenomenon suggests that flexible fiber suspensions can be exploited to produce a new family of flow-induced gelled materials, such as porous hydrogels. A significant consequence of these flow properties is that the microfiber suspension is injectable through a needle, from which it can be extruded directly as a hydrogel without any chemical reactions or further treatments. Additionally, we show that this fiber hydrogel is a soft, viscoelastic, yield-stress material.

Electrophoretic Deposition of Titanium Nitride Onto 316 Stainless Steel As a Bipolar Plate for Fuel Cell Application

The polymer electrolyte membrane fuel cell(PEMFC) is being considered as a clean source of power for the application of future energy owing to its high-power density, lower operating temperature than other fuel cells, and environment-friendliness [1]. For commercialization, the cost of bipolar plates (BPs) is a crucial factor among cell components, which comprises a high percentage of the total volume, weight, and the cost [2]. Graphite BPs is widely used due to high chemical stability and low surface contact resistance, but brittleness and machining cost are the critical concerns [3]. Stainless steel is commonly utilized an alternative material due to their high strength and chemical stability, low gas permeability. However, stainless steel suffers corrosion during PEMFC operation. Such corrosion deteriorates cell performance by dissolution of the metal ion into gas diffusion layer and increased interfacial contact resistance(ICR) of the formation of the passivation film [4]. Titanium nitride(TiN) can be one of the promising protective coating material in PEMFC due to the excellent durability, chemical stability, as well as good electrical conductivity. Various methods such as CVD [5], PVD [6], and sputtering [7] have been investigated to fabricate TiN films. In this study, we explore electrophoretic deposition (EPD) of TiN layers. It is known that EPD provides simple, versatile, easy adjustment of coating thickness and cost-effective method to fabricate homogeneous coatings onto complex shape as well as a porous substrate [8]. TiN powders were coated successfully onto a 316 stainless steel by EPD. The different particle size of TiN including 20nm, 80nm and 800nm TiN powders was used to investigate morphology of coating layers, EPD kinetics and mechanism. In addition, two kinds of additives, PDADMAC and PEI were used to obtain a uniform suspension and EPD mechanism. Although both additives cationic polymers, different polymeric structure and molecular weight would influence condition of suspensions and potentially properties of coating layers. The morphologies and structure of TiN coated surface were analyzed by SEM and XRD. The potentiodynamic and potentiostatic electrochemical tests were conducted to measure the corrosion resistance for the applicability of EPD of TiN as a protective layer of bipolar plate in PEMFC.

Nanoparticles as additive in biodiesel on the working characteristics of a DI diesel engine

Abstract This experimental work investigates the performance, combustion and emission characteristics of a single cylinder direct injection (DI) diesel engine with three fuel series: biodiesel–diesel (B20), biodiesel–diesel–nanoparticles (B20A30C30) and biodiesel–nanoparticles (B100A30C30). The nanoparticles such as Alumina (Al 2 O 3 ) and Cerium oxide (CeO 2 ) of each 30 ppm are mixed with the fuel blends by means of an ultrasonicator, to attain uniform suspension. Owing to the higher surface area/volume ratio characteristics of nanoparticles, the degree of mixing and chemical reactivity are enhanced during the combustion, attaining better performance, combustion and emission attributes of the diesel engine. The brake thermal efficiency of the engine for the nanoparticles dispersed test fuel (B20A30C30) significantly improved by 12%, succeeded by 30% reduction in NO emission, 60% reduction in carbon monoxide emission, 44% reduction in hydrocarbon emission and 38% reduction in smoke emission, compared to that of B100.

LiNi0.8Co0.15Al0.05O2: Enhanced Electrochemical Performance From Reduced Cationic Disordering in Li Slab

Sub-micron sized LiNi0.8Co0.15Al0.05O2 cathode materials with improved electrochemical performance caused by the reduced cationic disordering in Li slab were synthesized through a solid state reaction routine. In a typical process, spherical precursor powder was prepared by spray drying of a uniform suspension obtained from the ball-milling of the mixture of the starting raw materials. Then the precursor powders were pressed into tablets under different pressures and crushed into powder. The pressing treated powders were finally calcinated under oxygen atmosphere to obtain the target cathode materials. XRD investigation revealed a hexagonal layered structure without impurity phase for all samples and significant increase in the diffraction intensity ratio of I(003)/I(104) was observed. Rietveld refinement further confirmed the reduced cationic disordering in Li slab by such pressing treatment, and the smallest disordering was observed for sample S4 with only 1.3% Ni ions on Li lattice position. The electrochemical testing showed an improvement in electrochemical behavior for those pressing treated samples. The calculation of diffusion coefficients using EIS data showed improved Li diffusion coefficient after pressing treatment. The sample S4 presented a diffusion coefficient of 4.36 × 10−11 cm2·s−1, which is almost 3.5 times the value of untreated sample.

Cellulose nanofiber/carboxymethyl cellulose blends as an efficient coating to improve the structure and barrier properties of paperboard

Cellulose nanofibers (CNF) have been suggested in the literature as a potential barrier coating layer for paper and paperboard. However, due to its rheological properties and solids content, the material is difficult to apply to paper at significant coat weight levels. The use of CNF as a coating to improve the structure and barrier properties of paperboard was investigated. Two forms of CNF were used: (1) refiner produced material and (2) material produced with an ultra-fine grinder. Carboxymethyl cellulose (CMC) was used for some samples as an additive. The rheology of these suspensions was characterized. These materials were applied onto the surface of paperboard using a draw-down rod coater in two layers. Scanning electron microscope (SEM) was used to see the coverage of the paper by the CNF layer. Air permeability, water penetration and barrier properties of the samples were characterized. The steady shear viscosity of CNF suspension decreased after the addition of CMC. Although CNF at 2% solid content without CMC could not be spread out onto the surface of paper uniformly, 3% CNF along with CMC was successfully coated on the surface of paper: CMC acts as a dispersant that produces a uniform suspension with minimal flocs. The ground CNF with CMC produced the best samples with good coverage as revealed by SEM images. The results show that the structure and barrier properties of coated paperboards improved considerably by the application of CNF coatings.

Bottom water hydrodynamic provinces and transport patterns of the northern South China Sea: Evidence from grain size of the terrigenous sediments

Sediment transport in the source-to-sink systems of the northern South China Sea (SCS) has been of increasing interest during the past few decades. However, the mechanisms for sediment redistribution remain unclear. Sources and transport patterns in the northern SCS were investigated in this study based on grain size analyses of 205 surface sediment samples. Detailed characterizations of hydrodynamic conditions and sediment transport have been made using the log-ratio method to partition grain size components of surface sediments in the northern SCS. Results reveal that sediment dispersal patterns in the region generally contain traction, saltation, graded and uniform suspension modes. Based on the spatial distribution characteristics, the study area can be classified into three hydrodynamic provinces. Province A contains high traction concentrations that are exposed to the longshore current and topographic features, which are distributed in the Taiwan Shoal, Dongsha Islands and extends from the Pearl River estuary to the southeast of Hainan Island. Province B is characterized by higher values of saltation and graded suspension, which are widespread along the northern slope of the SCS, and its formation is interpreted as the result of interactions between down- and along-slope processes. Province C reaches its greatest concentration in the abyssal areas, particularly in the vicinity of Luzon Island, which settles only under calm conditions. Combined with previous data concerning magnetic susceptibility distributions of surface sediments from the northern SCS, the sediment transport route near the mainland is traced. Furthermore, based on distribution pattern of sortable silts and hydrodynamic provenance of the terrigenous sediments, the sediment transport route in the deep water region of the northern SCS is outlined. It flows along marginal channels which cut across the continental slope along isobaths. Taken together, the combination of grain-size components and sortable silts of surface sediment used here is a promising tool to better assess the modern variability of hydrodynamic conditions and transport processes in marine environments.

Lithofacies and particle-size characteristics of late Quaternary floodplain deposits along the middle reaches of the Ganga river, central Ganga plain, India

Floodplains are flat areas lining both sides of most rivers. They are commonly inundated during high flood events and are important sites of biodiversity and human occupation and cultivation. Big city centers such as Kanpur, Allahabad, Mirzapur and Varanasi are situated on the bank of the Ganga river in central Ganga plain, India. Cliffed embankments occur on the left side of the Ganga river around the village of Jhusi, Allahabad district and Adalpura, Mirzapur district, and on the right side around the town of Jajmau, Kanpur district, around the village of Sirsa, Allahabad district, around the town of Ramnagar, Varanasi district and the village of Tanda, Chandauli district. These cliff sections were studied to determine facies types and grain-size variations along and across the cliff sections in order to elucidate the mechanism of particle transportation and sedimentation on the floodplains. It was found that the majority of the facies are composed of extremely silty and very silty slightly sandy mud, and extremely silty and very silty sandy mud, a few consisting of slightly clayey silt. Both groundwater horizons and intercalated pedogenic calcretes in the muddy facies suggest pedogenesis under arid to semiarid climatic conditions during their development. Grain-size analyses show that mean particle size ranges from 4.23–6.53 phi (coarse to fine silt). Sorting (standard deviation) shows a range of 1.57–2.94 phi, indicating that all the samples are poorly to very poorly sorted. Skewness ranges from 0.09–0.88 (near-symmetrical to very fine skewed). Kurtosis varies from 0.75–1.54, with a few exceptions indicating mesokurtic to very leptokurtic size distributions. Plots of mean grain size vs. sorting suggest that sedimentation took place in a quiet fluvial environment in the course of numerous discharge episodes. Channel and floodplain deposits of the Ganga river are clearly distinguished in these plots. Furthermore, a plot of the coarsest percentile against the median diameter (C-M diagram) suggests that the sediments were transported in graded to uniform suspension.

ICANN New gTLD RPMs: Caveats of Intermediary Liability in Domain Name System

With the implementation of the ICANN’s new gTLD Program that is making the Internet domain name system (DNS) slate grow from 22 to thousands of top-level domains (TLDs), ICANN builds a series of right protection measures (RPMs) that require all new gTLD registries offer multiple safeguards, primarily, for intellectual property rights. The comprehensive and somewhat unprecedented RPMs include both the preventive measures as the Legal Right Objection (LRO) procedure, Sunrise and Trademark Claims and the curative measures as Uniform Rapid Suspension (URS), Post-Delegation Dispute Resolution Procedure (PDDRP) and Public Interest Commitment Dispute Resolution Process (PICDRP), covering both the top-level strings and sub-levels names before and after any new gTLDs are delegated by ICANN to the registries.

Direct dispersion of SWNTs in highly conductive solvent-enhanced PEDOT:PSS films

Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) is shown to be an effective dispersant for single-wall carbon nanotubes (SWNTs), enabling uniform aqueous suspensions to be obtained at weight loadings of up to 0.23 mg/ml (>1% by weight relative to PEDOT:PSS) without recourse to additional surfactants. Thin films spin-coated from PEDOT:PSS/SWNT suspensions exhibited sheet resistances of 90 Ω/sq. at 80 % transmittance, slightly higher than equivalent films of pure PEDOT:PSS which exhibited sheet resistances of 70 Ω/sq. at the same transmittance.

Combination Treatment for COPD

The FDA has approved a fixed-dose dual bronchodilator that combines glycopyrrolate and formoterol fumarate in a pressurized, metered-dose inhaler. The drug, marketed as Bevespi Aerosphere, is indicated for long-term, maintenance treatment of airflow obstruction in patients with chronic obstructive pulmonary disease (COPD) (http://1.usa.gov/1qVyi94). Glycopyrrolate is a long-acting muscarinic antagonist (LAMA) while formoterol fumarate is a long-acting β2-agonist (LABA). Manufacturer AstraZeneca said in a statement that the combination medication is the first FDA-approved product using its unique technology that distributes drug crystals in a uniform suspension formed with porous, low-density phospholipid particles. The technology prevents the drug crystals from settling or intermingling, allowing consistent doses of different drugs to be dispensed from a single pressurized metered-dose inhaler (http://bit.ly/1VBpmTq).

Detonability of aqueous suspensions of explosives

The detonability of aqueous suspensions of solid explosives (pentaerythritol tetranitrate, cyclotrimethylenetrinitramine, cyclotetramethylenetetranitramine) was used as a basis for evaluating the explosion safety of these substances in production and transportation. The dependence of the critical detonation parameters of the suspensions on the content and dispersity of the explosives was determined. A new common method for calculating the critical detonation diameters of suspensions of crystalline explosives in organic media and in water was developed. A novel procedure for preparing uniform sedimentation-resistant aqueous suspensions of crystalline explosives was suggested and developed.

Flexible route to fabricate excellent adsorbents for vitamin B 12 by specially designed oil‐drop process

This work presented the preparation of an excellent adsorbent composed of carbon nanotubes (CNTs) and activated carbon (AC) with hierarchical porous structure by specially designed oil-drop process. In this process, CNTs were pre-dispersed in the ethanol diluted phenolic formaldehyde resin and subsequently, the uniform suspension was injected dropwise into the stratified liquids. These liquids were composed of paraffin, polydimethyl siloxane and poly(ethylene glycol) (PEG)-6000 aqueous solution with different densities. After being semi-cured in the three-layered liquids at 70°C, the spheres were carbonised at 600°C and further activated at 800°C with steam. Scanning electron microscope observations indicated that compared with those prepared by two-layered oil bath in the authors’ previous work, the CNTs/phenolic resin spheres acquired by the modified oil-drop method would absorb PEG-6000 instead of polydimethyl siloxane and hence no residue of silica spheres produced in the final CNTs/AC spheres. Meanwhile, pore structure analyses indicated that the average diameter of the pores in the CNTs/AC spheres increased from 8.1 to 23.3 nm, which could be ascribed to the pore forming effect of PEG-6000. The adsorption capacity for vitamin B12 by the porous CNTs/AC spheres reached 52.98 mg/g, which was much higher than commercial AC beads and macroporous resin spheres. This implied that the CNTs/AC spheres could have potential applications in hemoperfusion.

Experimental investigation of the mixing of viscous liquids and non-dilute concentrations of particles in a stirred tank

Despite the importance for the process industry of solid–liquid mixing operations involving viscous liquids and high solids concentrations, most of the reported results have been obtained in the turbulent regime with low solids loadings. In this work, the suspension of non-dilute concentrations of spherical particles in viscous liquids is investigated through the determination of the just-suspended speed Njs, the homogenization speed NH and the homogenization time tH. The pitched blade turbine, which is a common and suitable agitator for the suspension of solids in the turbulent regime, is chosen. Njs is obtained using the pressure gauge technique, and NH and tH via electrical resistance tomography. The impact of the particle diameter dp, the solids mass concentration Xw, the liquid viscosity μ, and the impeller diameter D and off-bottom clearance C are assessed. In particular, the effect of dp and μ on Njs are observed to be in contradiction with the Zwietering correlation, which was derived in the turbulent regime. This is attributed to the hydrodynamics and mechanisms prevailing in the laminar and early transitional regimes, which are similar to those for the erosion of a particle bed. This also explains the discrepancies between our experimental values and the values of Njs predicted by the Zwietering correlation. Also, increasing Xw affects Njs in a more complex manner than what is predicted by this correlation. Finally, our results indicate that particle bed erosion is the dominating phenomenon to consider both to suspend the particles and achieve a uniform suspension in the tank.