Influences of oscillation on the physical stability and explosion characteristics of solid-liquid mixed fuel

The stratification phenomenon resulting from differences in the physical properties of solid-liquid components seriously affect the final combustion and explosion characteristics of mixed fuel under the action of oscillation.The effects of oscillation on the physical stability of mixed fuel with two solid-liquid ratios and three liquid component distribution ratios have been investigated using a self-designed experimental system at oscillation frequencies of 60-300 r/min.The explosion characteristics of mixed fuel before and after oscillation are gained from a 20 L spherical explosion container system.When the mass ratio of liquid components is controlled at 66.9%,64.7%,62.6%the final explosion characteristics are stable,with a maximum difference of only 0.71%.The volume of liquid fuel precipitation increases with increasing oscillation frequency when the mass ratio of liquid components reaches 71.7%,69.6%,67.7%.The fuel explosion overpressure after oscillation decreases with increasing liquid precipitation volume,and the repeatability is poor,with a maximum standard deviation of 82.736,which is much higher than the ratio without stratification.Properly controlling the mass ratio of liquid components of the mixed fuel can effectively combat the impact of oscillation on the physical state and maintain the stability of the final explosion characteristics.

Influence of liquid bridge force on physical stability during fuel storage and transportation

The physical stability of solid-liquid fuel is a factor that needs to be considered for fuel product practicability for storage and transportation. To determine the Influence of liquid bridge force on physical stability, two detection devices were designed. The laws obtained from microscopic experiments are used to verify the physical stability of fuel under different component ratios. The liquid bridge force is found to increase with the droplet volume. Multiliquid bridges above one critical saturation can generate significant resultant forces compared to single-liquid bridges of the same volume. There exist four states of solid-liquid mixed fuel with increasing liquid saturation rate. The liquid bridge force between the solid and liquid plays a dominant role in the physical stability of the first three states. There may be two stages involved in the stratification process for state 4 fuel, and the liquid viscosity is another factor that cannot be ignored. In the process of selecting a fuel ratio, a larger liquid bridge force between the components can be obtained by properly improving the wetting effect so that the fuel shows better physical stability.

Effect of Polyisobutylene Succinimide on the Physical Stability of an Environmentally Friendly Pesticide Oil Dispersion Suspension

Oil dispersible suspension concentrates are safe,green,and environmentally friendly formulations.Problems such as layering,pasting,and bottoming are frequently encountered during the production,storage,and transportation process.Polyisobutylene succinimide functions as a dispersant and exhibits great potential to improve the physical stability of the oil dispersible suspension concentrate.From a microscopic perspective,the sorption characteristics of the polyisobutylene succinimide dispersant T151 on penoxsulam particle surfaces were comprehensively evaluated with XPS,FTIR,and SEM.The T151 adsorption procedure complied with a pseudo-second-order kinetic adsorption model,and it was a kind of physical sorption with an Ea of 22.57 kJ⋅mol^(−1).The T151 sorption model was consistent with the Langmuir isotherm.The adsorption process was spontaneous and followed by an entropy increase.TheΔH^(θ)of dispersant T151 on the surface of penoxsulam particles was 31.59 kJ⋅mol^(−1).The adsorption procedure was endothermic,and the primary force was hydrogen bonding.The XPS results showed that the F and S electronic peaks at the penoxsulam interface decreased,and that the C electronic peak increased significantly after the adsorption of dispersant T151,indicating the adsorption on the surface of penoxsulam particles.The results of this study provide a vital theoretical basis for the application of polyisobutylene succinimide dispersants in oil dispersible suspension systems.

Physico-Chemical and Microbiological Study for the Stability of Phenytoin Sodium Extemporaneously Compounded Suspension in Saudi Arabia Hospitals

Epilepsy is a chronic and the fourth most common neurological disorder which affects people of all age groups. Recently research and awareness on epilepsy-related deaths have rapidly grown over the past two decades. Many previous studies are attributed to the guidelines that apprise health care professionals in handling these deaths, but there is a relative scarcity of information accessible for clinicians and pharmacists who are responsible for manufacturing or preparing the extemporaneous anti-epileptic suspensions in the hospitals. Mostly in partial seizures, phenytoin is one of the first-choice drugs. In Saudi Arabian hospitals, the extemporaneous preparation of phenytoin suspension is common, but the hot climatic weather in Saudi Arabia possesses stability problems that should be tackled as the prepared suspension should pass all the stability tests to ensure uniform dosage of the extemporaneous formulation. In the current study, the commercial capsules were used to prepare the oral phenytoin sodium extemporaneous suspension. The physical, chemical and microbiological stability of phenytoin sodium suspension is analyzed at various temperatures.

Correlation of Cooperatively Localized Rearrangement on the ＂Fluidized Domain＂ of Polymers to Their Nonexponentially Viscoelastic Behavior and Lifetime at Double Aging Processes II： Estimation of Long-term Mechanical Behavior and Lifetime of Polymeric Materials from Short-time Creep and Stress Relaxation Tests

Three kinds of polymeric materials are taken as example for the verification of linear ex-trapolation method from unified master lines with reduced universal equations on creep and stress relaxation tests. The theoretical values of long-term mechanical behavior and lifetime for a cured epoxide, polypropylene, poly（methyl-methacrylate）, and SBR rubber are directly evaluated with the universal equations on reduced creep compliance and reduced stress relax-ation modulus and are compared with their predicted values by the linear extrapolation from the unified master lines of creep and stress relaxation. The results show that the theoretical values of dimensional stability, bearing ability and lifetime are in an excellent agreement with the predicted values, it shows that the linear extrapolation method is more simple and reliable. The dependences of long-term mechanical behaviors and lifetime on the different aging times are discussed.

Preparation of stable colloidal suspensions of superdisintegrants via wet stirred media milling

Superdisintegrants are cross-linked polymers that can be used as dispersants for fast release of drug nanoparticles from nanocomposite microparticles during in vitro and in vivo dissolution. Currently avail- able superdisintegrant particles have average sizes of approximately 5-130 μm, which are too big for drug nanocomposite applications. Hence, production of stable superdisintegrant suspensions with less than 5 μm particles is desirable. Here, we explore the preparation of colloidal suspensions of anionic and nonionic superdisintegrants using a wet stirred media mill and assess their physical stability. Sodium starch glycolate （SSG） and crospovidone （CP） were selected as representative anionic and nonionic superdisintegrants, and hydroxypropyl cellulose （HPC） and sodium dodecyl sulfate （SDS） were used as a steric stabilizer and a wetting agent/stabilizer, respectively. Particle sizing, scanning electron microscopy, and zeta potential measurements were used to characterize the suspensions. Colloidal superdisintegrant suspensions were prepared reproducibly. The extensive particle breakage was attributed to the swelling-induced softening in water. SSG suspensions were stable even in the absence of stabilizers, whereas CP suspensions required HPC-SDS for minimizing particle aggregation. These findings were explained by the higher absolute （negative） zeta potential of the suspensions of the anionic superdisintegrant （SSG） as compared with those of the nonionic superdisintegrant （CP）.