Drop Of Suspension Research Articles

Droplet ignition of coal–water slurries prepared from typical coal- and oil-processing wastes

The requirements for stable ignition (and subsequent combustion) of fuel suspensions prepared from typical coal- and oil-processing wastes are studied experimentally. Attention focuses on the differences between the ignition characteristics of coal–water slurries (containing petrochemicals) obtained on the basis of filter cakes containing T, K, SS, Zh, D, and G coal. To eliminate the influence of the droplet holder (traditionally, thermocouple junctions, ceramic rods, or metal wire) on the ignition characteristics of the fuel droplet, the experiments employ a special model combustion chamber and a device for introducing a single drop of suspension. The ignition time and the minimum temperature of stable ignition of a droplet of coal–water slurries suspended in an oxidant flux are established. The influence of the following factors on the initiation of fuel combustion is determined: the oxidant temperature, the droplet size, the size of the coal dust, and the properties and concentrations of the components. The compositions of the coal–water slurries corresponding to optimal ignition (minimum inertia) are identified.

Nimodipine Ophthalmic Formulations for Management of Glaucoma

Preparation and evaluation of topical ophthalmic formulations containing nimodipine-CD complexes prepared using HP-β-CD, SBE-β-CD and M-β-CD for the management of glaucoma. Nimodipine-CD complexes were prepared using a freeze-drying method. Two different molar ratios (NMD:CD) were used for each cyclodextrin. The inclusion complexes were characterized using DSC, FTIR, yield (%), drug content and in vitro release characteristics. NMD-CD complexes incorporated into chitosan eye drops and a temperature-triggered in situ gelling system were evaluated for their pH, viscosity and in vitro release characteristics. We determined the intraocular pressure (IOP) lowering effect of NMD-hydroxypropylmethylcellulose (HPMC) eye drops through a single dose response design using C57BL/6J mice. The minimum effective concentration (MEC) of nimodipine was further applied to mice that vary in the parental allele of Cacna1s, the drug target of nimodipine. Cytotoxicity was also evaluated. Our ophthalmic formulations possessed pH and viscosity values that are compatible with the eye. In vitro release of nimodipine was significantly increased from chitosan eye drops containing NMD-CD complexes compared to uncomplexed drug. Administration of nimodipine can lower IOP significantly after a single drop of drug HPMC suspension. The IOP-lowering response of the MEC (0.6%) was significantly influenced by the parental allele of Cacna1s. Nimodipine can be used as a promising topical drug for management of glaucoma through ocular delivery.

Experimental Study of the Ignition of Single Drops of Coal Suspensions and Coal Particles in the Oxidizer Flow

Experimental Study of the Ignition of Single Drops of Coal Suspensions and Coal Particles in the Oxidizer Flow

菌体ドロップ法によるイネいもち病菌のQoI剤耐性菌検定

菌体ドロップ法によるイネいもち病菌のQoI剤耐性菌検定

Correlation study of resistance components in the selection of Capsicum genotypes resistant to the fungus Colletotrichum gloeosporioides.

Anthracnose is among the major diseases of the Capsicum culture. It is caused by different species of the genus Colletotrichum, which may result in major damages to the cultivation of this genus. Studies aiming to search for cultivars resistant to diseases are essential to reduce financial and agricultural losses. The objective of this study was to evaluate the correlation between the variables analyzed to select Capsicum genotypes resistant to the fungus Colletotrichum gloeosporioides. The experimental design was completely randomized blocks with three replications, 88 treatments, four ripe fruits, and four unripe fruits per replication. Accessions of Capsicum from the Germplasm Active Bank of Universidade do Estado de Mato Grosso (UNEMAT) were evaluated as for resistance to the fungus. Fruits were collected from each plot and taken to the laboratory for disinfestation. A lesion was performed in the middle region of the fruit using a sterile needle, where a spore suspension drop, adjusted to 106 spores/mL, was deposited. An ultrapure water drop was deposited into control fruits. The fruits were placed in humid chambers, and the evaluation was performed by measuring the diameter and the length of lesions using a caliper for 11 days. After data were obtained, analyses of variance, correlation, and path analysis were performed using the GENES software and R. According to the likelihood-ratio test, the effects of genotypes (G), fruit stage (F), and its interaction (G x F) were significant (P < 0.05). There were differences between the magnitudes of genotype correlations according to fruit stage. Different variables must be taken into account for an indirect selection in this culture in function of fruit stage since the variable AUDPC is an important criterion for selecting resistant accessions. We found through the path analysis that the variables DULRD and DULRL exerted the greatest effects on AUDPC.

Settling of particle-suspension drops at low to moderate Reynolds numbers

The evolution of suspension drops settling in a fluid at low to moderate Reynolds number (based on drop sizes) is investigated experimentally. With increasing Reynolds number, it is found that the shape of the drop changes more rapidly with traveling length before breakup decreases. Also, the aspect ratio of the drop at breaking up, and the number of secondary droplets after breaking up increase with the Reynolds number. Our findings are consistent with previous simulation studies. The evolution and breakup mechanisms of a settling suspension drop at low to moderate Reynolds number are different to those at creeping flow limit.

Electric charge of a lightning ball

The electric charge of a lightning ball is found by comparing the electrohydrodynamic stabilities of a charged drop in an electrostatic suspension and a lightning ball floating in a superposition of the gravitational field and the surface electric field. It has been assumed that the electric field strength at the surface is limited by a breakdown value. For a lightning ball radius of 15 cm, its charge is estimated as several microcoulombs. Accordingly, the density of electrostatic energy accumulated in the lightning ball is on the order of one-hundredth of a joule per square centimeter. The density of the material that constitutes the lightning ball has been estimated for the case when the electric field strength at the site of its origination is several times higher than that in fine weather. The density of the lightning ball turns out to differ from that of air by only a few percents.

WO3 nano-rods sensitized with noble metal nano-particles for H2S sensing in the ppb range

Hydrothermally grown hexagonal WO3 nano-rods were sensitized by additional Pt and Au nano-particles. The size of the 20–29nm noble metal nano-particles were stabilized with methoxy-polyethylene glycol, and their solution was mixed with the tungsten-oxide nano-rod suspension. Controlled sized suspension drops of activated and pure reference material were deposited on the top of micro-hotplate with gold interdigital electrodes on top. The gas sensitive properties were measured for NH3 and H2S in a temperature range of 140–300°C. Noble metal nano-particles multiplied the gas sensitivity for H2S, whereas no significant effect could be detected for NH3. With gold nano-particles a lower detection limit of 25ppb could be achieved. The response time is in the range of 30–80s, whereas typically 300s is needed for complete recovery.

Particle dynamics and relaxation in bimodal suspensions during drying using multispeckle diffusing wave spectroscopy

The motion of polystyrene particles in a bimodal suspension drop during drying was characterized via multispeckle diffusing wave spectroscopy. The fast and slow dynamics of bimodal particles, which were expressed in terms of autocorrelation function data from two kinds of cameras, were well connected in short and long lag time regimes. Characteristic time of β‐relaxation, representing the rapid movement of bimodal particles, became lower in the short lag time region as the portion of small particles increased, reflecting their fast Brownian motion. The difference in the relaxation features between bimodal suspension with large and small particles and unimodal suspension with only large particles became more evident as the size ratio between particles was high. Drying temperature could encourage the particle movement at the early stages of drying, leading to lower relaxation time, and inversely retard the relaxation behavior when drying time further elapsed, due to the structural rearrangement of particles. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1114–1121, 2017

Understanding the Formation of Anisometric Supraparticles: A Mechanistic Look Inside Droplets Drying on a Superhydrophobic Surface.

Evaporating drops of nanoparticle suspensions on superhydrophobic surfaces can give anisotropic superaparticles. Previous studies implied the formation of a stiff shell that collapses, but the exact mechanism leading to anisotropy was unclear so far. Here we report on a new experiment using confocal laser scanning microscopy for a detailed characterization of particle formation from droplets of aqueous colloidal dispersions on superhydrophobic surfaces. In a customized setup, we investigated droplets of fumed silica suspensions using two different fluorescent dyes for independently marking silica and the water phase. Taking advantage of interfacial reflection, we locate the drop-air interface and extract normalized time-resolved intensity profiles for dyed silica throughout the drying process. Using comprehensive image analysis we observe and quantify shell-like interfacial particle accumulation arising from droplet evaporation. This leads to a buildup of a stiff fumed silica mantle of ∼20 μm thickness that causes deformation of the droplet throughout further shrinkage, consequently leading to the formation of solid anisometric fumed silica particles.

Morphological patterns of controlled particle dispersion by photoisomerization of spiropyrans

This work describes an interesting morphological control of the microstructures of photoactive spiropyrans. These microstructures exhibit reversible photoisomerization in solid state under different light irradiation. To observe morphological changes intuitively caused by volume expansion of spiropyrans, a special film is synthesized with inverse conical-hole structures by biomimetic method. When a drop of spiropyran-silica mixture ethanol suspension is placed on the film and dried naturally, almost all spiropyran-silica mixture particles gather into inverse conical holes of the film. Then mixture particles in holes start distributing on edge areas of holes on the film under illumination of 365nm UV light, spread evenly on the whole surface of the film, and finally convert into self-assembled structures. In addition, particle state can recover to its original state, when irradiate with visible light.

Drop impact of shear thickening liquids

The impact of drops of concentrated non-Brownian suspensions (cornstarch and polystyrene spheres) onto a solid surface is investigated experimentally. The spreading dynamics and maxi- mal deformation of the droplet of such shear thickening liquids are found to be markedly different from the impact of Newtonian drops. A particularly striking observation is that the maximal de- formation is independent of the drop velocity and that the deformation suddenly stops during the impact phase. Both observations are due to the shear-thickening rheology of the suspensions, as is theoretically explained from a balance between the kinetic energy and the viscously-dissipated en- ergy, from which we establish a scaling relation between drop maximal deformation and rheological parameters of concentrated suspensions.

Impact of the collective diffusion of charged nanoparticles in the convective/capillary deposition directed by receding contact lines.

The motion of electrically charged particles under crowding conditions and subjected to evaporation-driven capillary flow might be ruled by collective diffusion. The concentration gradient developed inside an evaporating drop of colloidal suspension may reduce by diffusion the number of particles transported toward the contact line by convection. Unlike self-diffusion coefficient, the cooperative diffusion coefficient of interacting particles becomes more pronounced in crowded environments. In this work, we examined experimentally the role of the collective diffusion of charge-stabilized nanoparticles in colloidal patterning. To decouple the sustained evaporation from the contact line motion, we conducted evaporating menisci experiments with driven receding contact lines at low capillary number. This allowed us to explore convective assembly at fixed and low bulk concentration, which enabled to develop high concentration gradients. At fixed velocity of receding contact line, we explored a variety of substrate-particle systems where the particle-particle electrostatic interaction was changed (via p H) as well as the substrate receding contact angle and the relative humidity. We found that the particle deposition directed by receding contact lines may be controlled by the interplay between evaporative convection and collective diffusion, particularly at low particle concentration.

Surface roughness induced cracks of the deposition film from drying colloidal suspension.

We investigate crack formation in deposition films from drying colloidal suspension drops, by varying the roughness and texture of the substrate. The experimental results indicate that the crack number or crack spacing presents a general dependence on the substrate roughness, despite the orientation of the substrate textures. Interestingly, the crack spacing decreases with the increase of the roughness. Two possible mechanisms are proposed to understand the dependence of the cracks on roughness. Firstly, the concentration reduction of the drying suspension due to collecting colloidal particles from the substrate textures decreases the crack spacing. Secondly, stress concentration resulting from the defects (the notches in textures) in the dried deposition enhances crack formation. However, a quantitative estimation by the calculation of the stress concentrating factors reveals that the notch of the substrate textures dominates crack variation. The results here bring forth a practical method for controlling the crack orientation and suppression, and a potential application to crack-free coatings, films and paintings during the drying of complex fluids.

Characterising canola pollen germination across a temperature gradient

If predictions are correct, heat stress during reproduction will become a yield limiting factor in many world crops and breeding heat stress tolerance a major goal. The objective of our paper was to highlight a novel system to investigate the influence of temperature (T) on pollen germination using a thermal gradient PCR programmed to establish differential Ts across 12 wells of a PCR plate. Seven cultivars of Brassica napus L. were grown through flowering in a cool growth cabinet (20/15°C day/night) or a heat stress cabinet (HST, 27/22°C day/night). Pollen from each cultivar × cabinet combination was aspirated from 6 opened flowers, and suspended in germination media. Drops of the pollen suspension were floated on media in each well, and the PCR T was set to 30°C with a gradient of ± 10°C, creating a range from ~20 to 40°C from left to right. After an 8 h treatment, the pollen germination (pg, %) and pollen tube growth score (ptg, 1–5) were evaluated using a microscope. There were significant differences among cultivars for pg and ptg score and significant differences among well T for pg and ptg score. Pollen tubes grew best at T from 20 to 23°C. Well T exceeding 33°C reduced pg and ptg score, although 3 of the 8 cultivars had good pg even at 36°C. HST &gt;29°C, in a growth cabinet, generally resulted in B. napus raceme sterility, although our experiment showed that pollen was still capable of germinating up to 33°C, indicating that pollen germination may not be the only reason for heat stress susceptibility.

Preparation and attachment of liquid-infused porous supra-particles to liquid interfaces

We prepared model porous composite supra-particles and investigated the effect of the initial infused fluid phase on their attachment at the liquid-fluid interface. We used a simple method for fabrication of millimetre-sized spherical porous supra-particles from much smaller monodisperse latex microparticles as building blocks by evaporation of a polystyrene sulphate latex suspension on a hot super-hydrophobic surface. We annealed the dried supra-particles at the polymer's glass transition temperature to fuse partially their latex particle building blocks. Spherical porous supra-particles were produced above 40 wt% initial concentration of the latex particles in the suspension, which had a rough surface, with a porous and amorphous structure. We controlled the supra-particle size by varying the initial volume of the latex suspension drop, the latex particle concentration and the drop evaporation temperature. This preparation technique allowed limited control over the porosity of the supra-particles by varying the initial concentration of the latex particle suspension, the rate of evaporation and the annealing temperature. We characterised the surface morphology and the inner structure of supra-particles by SEM imaging. We report for the first time results of an MRI study of supra-particles attached to an air-water or an oil-water interface, which indicated that only the surface layer of the building block particles attaches to the liquid interface while the pore fluid was not displaced by the outer fluid. We observed that supra-particles infused with water had different wettability and attachment positions at the oil-water interface compared with the same particles infused with oil. Similarly, the infusion of the porous supra-particles with water led to a different attachment at the air-water interface compared to the attachment of the same supra-particle when dry. The fundamental importance of this result is that the porous particles (or colloid particle agglomerates) may give an oil-in-water or water-in-oil Pickering emulsion depending on whether they are initially impregnated with oil or water. The results of this study are relevant for particle-stabilised emulsions and foams in a range of pharmaceutical, food and cosmetic formulations as well as ore flotation.

The clinical effect of ibuprofen in treatment of severe hand foot mouth disease and its effect on relative cytokines

Objective To investigate the clinical effect of ibuprofen in treating severe hand foot mouth disease and its effect on serum IL-6,TNF-αand IL-8. Methods 154 cases of severe hand foot and mouth disease were randomly divided into conventional treatment group and ibuprofen treatment group(each group 77 cases).And 77 cases of hand foot and mouth disease in the same period were admitted as normal control group.,.Two treatment group were given conventional antiviral and symptomatic treatment, ibuprofen treatment group was conducted with application of ibuprofen suspension liquid or drops of oral or nasal feeding. The clinical symptoms and signs, blood biochemical indexes, cerebrospinal fluid index and related cytokines were observed in the ibuprofen treated group and the routine treatment group. Results 72 hours after treatment, the treated with ibuprofen group of body temperature(t= 10.330,P=0.000),respiration(t=2.460,P=0.016),pulse(t=3.200,P=0.002)and blood pressure(Systolic pressure:t=2.000,P=0.049,Diastolic blood pressure:t=4.890,P=5.42)better than the conventional treatment group, cerebrospinal fluid pressure(t=3.330,P=0.001),protein(t=3.370,P=0.001),cell number(t=3.780,P=0.0003) and sugar level(t=3.410,P=0.001)were lower than the conventional treatment group;serum IL-6(t=6.961,P= 1.038),IL-8(t=4.229,P=6.463),and TNF-α(t=2.020,P=0.047)were significantly lower than those of the conventional treatment group,the differences had statistical significance(P<0.05). In addition,the treatment group of ibuprofen was superior to the conventional treatment group in the hot withdrawal time(t=5.210,P=1.59)and average hospitalization days(t=3.090,P=0.003). Conclusion Severe hand foot and mouth disease on the basis of routine treatment plus cloth ibuprofen treatment,is ideal effect, and can regulate the serum IL-6,IL-8,and TNF-α.It is worthy of popularization and application. Key words: Buprofen; Cytokine; Hand-foot-mouth disease

Case study: Use of A2 and donor red blood cells for anti ABO a titer

ABO incompatibility (ABOi) is no longer an absolute contraindication for kidney transplantation. Recipients who are either blood group O or B have successfully received kidney transplants from donors who are blood group A, as long as their titer against the donor A antigen is low. Although the predominant A antigen subtype in the population is A1, less than 20% of blood group A individuals are of other subtypes, with weaker antigen expression, A2 being the most common of these. Accurate quantification of the amount of Anti A antibody titer in the recipient against the intended donor is important to determine compatibility for ABOi transplants. A review of the literature demonstrated that there is a high degree of technique variability, especially concerning the target cells utilized to determine such titers. Accordingly, we decided to use A2 and donor RBCs as well as our standard A1 RBCs in our assays, in order to determine the differences in titer when various A subtype cells are utilized as the target. Our case is a 54 year old male; 0% CPRA, blood group O recipient, whose donor was ABO typed as a non-A1. Flow T and B cell crossmatch negative. The transplant program decided to move forward with the ABO incompatible transplant since no other live donors were available. Determination of the Anti-A titer was as follows: Recipient sera was serially diluted with saline from 1:1 to 1:512. One drop of RBC suspension is added to 2 drops (100 ul) of each sera dilution. Three different titrations were performed using commercially produced A1 and A2 RBC as well as donor RBC. Tubes were incubated at RT for 30 minutes, centrifuged and agglutination macroscopically observed and recorded. Tubes were then incubated at 37C for 30 minutes, washed 4 times with saline, IgG added then centrifuged and agglutination recorded again. This procedure allows for determination of both IgM and IgG antibodies against blood group A antigens. IgG titers were 1:16 with A1 RBC; 1:8 with A2 RBC; and 1:8 with donor RBC. Our transplant program considers an IgG titer less than or equal to 1:8 acceptable and the transplant was performed. Recipient is out 11 weeks with no rejection episodes.

Temperature‐Sensitive Hydrogel‐Particle Films from Evaporating Drops

A simple method to prepare temperature‐sensitive films composed of micrometer‐sized colloidal hydrogel particles using evaporating drops of colloidal suspensions is demonstrated. The films range in thickness from a monolayer to approximately fifty particle diameters depending on initial particle volume fraction. Sessile droplets of hydrogel‐particle suspensions are evaporated on silicon wafers. The film is formed from particles spread densely over the air–water interface which then cross‐link and are deposited on the surface during the evaporation process. The resultant thin films exhibit a temperature‐responsiveness characteristic of the individual particles permitting modulation of size, shape, porosity, and optical transmission.

Understanding the growth of RuO2 colloidal nanoparticles over a solid support: An atomic force microscopy study

Peak Force Tapping-mode AFM is used to investigate the three-dimensional morphology of RuO2 nanoparticles supported on a solid surface, with sub-nanometer spatial resolution. Samples were prepared by spin coating (i) a drop of RuO2 colloidal suspension onto a mica sheet, followed by further treatments (drying, calcination and/or reduction), and (ii) a second drop of colloidal suspension on fresh, dried or calcined RuO2-mica. RuO2 crystallites are supported with a certain distribution of sizes, and this heterogeneity is essentially maintained after high-temperature treatments. After calcination, single coated RuO2-mica samples present small RuO2 crystallites (4.5nm height) as well as nanorod-like assemblies (14nm height). A disaggregation of particles occurs during the reduction treatment. Double coating RuO2 over non-calcined RuO2-mica samples involves mechanical effects causing re-dispersion of supported clusters. An intermediate drying step is unable to prevent re-dispersion of particles and even leads to repulsion between dehydrate RuO2 supported particles and hydrated particles in suspension. Meanwhile, a calcination step prevents re-dispersion and promotes growth of supported crystallites. Nanorods formed by single RuO2 deposition exhibit mostly regular flat surfaces, while a second RuO2 deposition on calcined RuO2-mica samples leads to larger nanorods with stepped surfaces (terraces), a favourable geometry for ammonia synthesis reaction.