Numerical simulation study on the influence of bend diameter rate on the flow characteristics of nature gas hydrate particles.

Bend pipe is a common part of long distance pipeline. There is very important to study the flow law of hydrate particles in the bend pipe, and pipeline design will be optimized. In addition, the efficiency and safety of pipeline gas transmission will be improved.

Biological Characteristics of Strain MJ1015 and Optimization of Solid Medium Technology for Sporulation.

The entomopathogenic fungus strain MJ1015, recently isolated from white grubs on a blueberry farm in Guizhou, China, could be used as a biocontrol agent. As a first step toward determining the effect of different solid culture media, temperature, and pH on colony growth rate and sporulation, we evaluated the optimum solid medium for mycelial growth and conidia production on a commercial scale. Subsequently, we also used single-factor analysis and response surface optimization to optimize the composition of the solid culture medium.

Numerical Simulation Study on the Flow Field and Separation Efficiency by Built-In Twisted Tape in the Hydrocyclone.

Aiming at the separation of mud and sand in natural gas hydrate, for the designed built-in twisted tape hydrocyclone, the numerical simulation method was used to study the effects of different types of built-in twisted tape and operating conditions on the internal flow field of the hydrocyclone, separation efficiency, and influence of hydrate particle size distribution. The research results show that the built-in twisted tape has the same swirling direction as the hydrocyclone, which is beneficial to improving the swirling intensity, and the ability to carry and separate solid particles is obviously enhanced. The built-in twisted tape hydrocyclone with a length of 300 mm has better separation efficiency and internal flow field stability.

Numerical Simulation of the Flow Pattern of Spiral Annular Flow with a Guide Strip by Spiral On-Way.

To study the gas-liquid two-phase spiral annular flow pattern and its conversion law in a horizontal tube with twist tape by spiral on-way, a numerical simulation is carried out using the RNG k-ε model, and the DPM model is adopted as the particle motion model. The research results show that three main flow patterns are obtained, which are spiraling churn flow, spiraling annular flow, and spiraling annular twine flow. The ratio of the liquid-phase to gas-phase velocity / is the main factor that affects the existence of the gas phase.

Experimental Study on Hydrate Safe Flow in Pipelines under a Swirl Flow System.

With the development of oil and gas resources gradually extending to the deep sea, the blockage of gas hydrate is attracting more and more attention. How to inhibit hydrate blockage efficiently and economically in oil and gas gathering transportation pipelines and ensure the safe operation has become a hot and difficult point in the field of oil and gas gathering and transportation research. At present, the research on the safe flow of gas hydrate is still in the exploratory stage, and applying swirl flow to hydrate risk control technology has a great engineering application value.

Numerical Simulation on the Flow Pattern of a Gas-Liquid Two-Phase Swirl Flow.

The gas-liquid contact area can be increased by the gas-liquid swirl flow, and the heat and mass transfer efficiency between gas and liquid can be enhanced by the gas-liquid swirl flow. The gas hydrate formation can be promoted by the swirl flow. The swirl flow can ensure the safety of the natural gas hydrate slurry.

Magnetic modulation of core@shell MoS-based flower-like multicomponent nanocomposites to improve microwave attenuation.

Nanocomposites with a three-dimensional (3D) flower-like geometrical morphology were considered as excellent microwave absorbers (MAs) because of the numerous effective sites for the multiple reflections of electromagnetic (EM) wave. Herein, for optimizing the EM matching characteristic and taking full advantage of interface polarization, a strategy of magnetic modulation was proposed to further improve the EM wave absorption performances (EMWAPs) of MoS-based nanocomposites. We adopted a simple hydrothermal route and a combined method of hydrothermal treatment/hydrogen reduction to synthesize core@shell CoFeO@MoS and CoFe@MoO/MoS flower-like nanocomposites, respectively.

Numerical Simulation of Swirl Flow Characteristics of CO Hydrate Slurry by Short Twisted Band.

The development of oil and gas resources is gradually transferring to the deep sea, and the hydrate plugging of submarine pipelines at high pressures and low temperatures is becoming an important problem to ensure the safety of pipeline operations. The swirl flow is a new method to expand the boundary of hydrate safe flow. Numerical simulation of the hydrate slurry flow characteristics in a horizontal pipeline by twisted band has been carried out, and the flow of CO hydrate slurry in low concentration has been simulated by the RSM and DPM models.

Numerical Simulation Study on Flow Laws and Heat Transfer of Gas Hydrate in the Spiral Flow Pipeline with Long Twisted Band.

The natural gas hydrate plugging problems in the mixed pipeline are becoming more and more serious. The hydrate plugging has gradually become an important problem to ensure the safety of pipeline operation. The deposition and heat transfer characteristics of natural gas hydrate particles in the spiral flow pipeline have been studied.

CO hydrate formation kinetics based on a chemical affinity model in the presence of GO and SDS.

Hydrate generation promotion and kinetic models are key issues in the hydrate utilization technology. The formation kinetics of CO hydrates in a graphene oxide (GO) and sodium dodecyl sulfate (SDS) compounding accelerator system was studied experimentally, and the influences of different concentrations on the hydrate formation time and gas consumption were revealed. The results show that with the combination of GO and SDS, the formation rate of CO hydrates was accelerated, the induction time and generation time were shortened, and the gas consumption increased.

The electrical properties and modulation of g-CN/β-As and g-CN/β-Sb heterostructures: a first principles study.

The electronic properties of the g-CN/β-As and g-CN/β-Sb heterojunctions are investigated density functional theory. We find that both heterostructures are indirect band gap semiconductors that, when applied to a photocatalytic device, will suffer from inefficient light emission. Fortunately, the band gap of the two junctions can be adjusted by external biaxial strain.

Pd/Pt embedded CN monolayers as efficient catalysts for CO oxidation.

Single atom catalysts (SACs) based on 2D materials have been identified to be efficient in many catalytic reactions. In this work, the catalytic performance of Pd/Pt embedded planar carbon nitride (CN) for CO oxidation has been investigated via spin-polarized density functional theory calculations. We find that Pd/Pt can be firmly anchored in the porous CN monolayer due to the strong hybridization between Pd/Pt-d orbitals and adjacent N-2p orbitals.

Study on the influence of coconut oil on flow pattern and pressure drop of two-phase swirl flow.

In view of the widespread existence of swirl flow in surfactant systems in oil drilling, gas gathering, and gathering pipelines, surfactants can affect interfacial tension and thus change the flow pattern. In order to further study and master the swirl flow characteristics in surfactant systems, this experimental investigation was presented, focused on gas-liquid flow during swirl flow, and aiming to evaluate the effect of surfactant in flow patterns. The experimental medium was air and water, the swirler was a vane and the surfactant was natural coconut oil.

CN: an excellent catalyst for the hydrogen evolution reaction.

Based on first-principles calculations, we study the hydrogen evolution reaction (HER) on metal-free C2N and make efforts to improve its catalytic performance. At H* coverages (θ) of 3/6 and 4/6, the free energy of hydrogen adsorption (ΔGH*) is 0.10 eV and 0.

Modulation of electronic and magnetic properties of edge hydrogenated armchair phosphorene nanoribbons by transition metal adsorption.

Based on first-principles calculations, we present a systematic investigation of the electronic and magnetic properties of armchair phosphorene nanoribbons (APNRs) functionalized by 3d transition metal (TM) atoms. We found that the central hollow site is the most favorable adsorption site for Mn, Co and Ni, while Fe preferentially occupies the edge hollow site. All of the TM atoms bind to the adjacent P and their adsorption energies are in the range of -4.

Electrical and optical behaviors of SiC(GeC)/MoS heterostructures: a first principles study.

Hybrid structures have attracted a great deal of attention because of their excellent properties, which can open up a way we could not foresee in materials science and device physics. Here, we investigate the electrical and optical behaviors of SiC(GeC)/MoS heterostructures, using first principles calculations based on density functional theory. Non-covalent bonding exists between the junctions due to the weak orbital coupling.