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Problems in paraffin deposition occur frequently in oil exploitation. Considering the problem that some paraffin removal and prevention strains cannot grow in high-salinity reservoirs, we domesticated four salt-tolerant laboratory bacterial strains. Crude oil emulsification effect, paraffin removal rate, and paraffin prevention rate of the strains were evaluated. KB and JH-A strains exhibited good paraffin removal and prevention effects, with paraffin removal rates of 51.82% and 81.56%; and 51.82% and 80.90%, respectively. Gas chromatography mass spectrometry analysis of paraffin components before and after biodegradation was performed on KB and JH-A strains. Results showed that relative contents of n-alkanes between C15–C23 and C27–C30 evidently decreased, indicating their good biodegradation. This technique provides a new method for practical application of paraffin removal and prevention in high-salinity reservoirs.

Through comprehensive investigation of a building accident, this paper analyses the reason of unevenly floating phenomenon in an underground garage subjected to a rainstorm and puts forward some reinforcement measures to the damaged members in the structure accordingly. The damaged status investigation of the garage structure is focused on the pile corresponding to the largest deformation column. Coring samples from damaged piles, the status of them can be obtained accordingly. Checking the garage design with investigated data, the cause of the uneven rise is concluded. Combined with the damage degree difference between structure components, the retrofit measures are put forward. First, cover the garage roof with proper depth of soil pressure, and then reinforce the cracked beams, columns and slabs, respectively. Second, plant bar into the broken pile and inject grout around the pile with high pressure. Finally, add prestressed anchors in the deformation foundation floor.

The adhesion properties of graphene nanofilm are studied by finite element simulation according to an approach of blister test. The critical debonding load and debonding deflection are calculated, and their dependence on the geometrical dimensions of the graphene nanofilm is analysed when the graphene nanofilm begins to debond from the substrate. The results of simulation show a good agreement with the theoretical results as well as the corresponding experiment results. Furthermore, the influence of adhesion energy and graphene thickness on the debonding behaviour of graphene nanofilm is also investigated, and the results show that there exist an obvious size effects for the critical debonding load and debonding deflection.

The top-blown oxygen jet behaviours at different stagnation temperatures in converter steelmaking process were investigated by using numerical simulation technique. The multiphase flow in top-blown...

To resolve the poor weldability of ductile irons, this study employed AISI 1008 low carbon steel in the pure ferrite phase as the top plate and ductile iron as the bottom plate and varied the rotational speeds combined with travelling speeds that ranged between 40 and 70 mm min−1 to conduct a friction stir lap welding test. After welding, the weldments underwent microstructure analysis and hardness testing followed by a tensile shear test to evaluate the joint strength. At low rotational speeds

Three field experiments were conducted using a surface currents ultra-high frequency (UHF) radar system at fresh water during 2005. Two geometries for the transceiver antennas were examined: bistatic on a bank with an obstruction between them and backscatter on a bank. Echo Doppler spectra from a lake and two rivers were observed and interpreted. The first-order Bragg-echoes with Signal-to-Noise Ratios (SNR) of 20–50 dB were received and the maximum range was about 500 m with about 2∼3 w of transmitter power. Along-river surface currents have been measured using the UHF radar system. Comparisons with a conventional propeller-type current meter indicated that currents measured by UHF radar closely tracked in-situ current measurements.

This paper presents an adjustable singular perturbed parameter approach, which is based on the Lyapunov stability theorem, in the stability analysis of multi-parameter singularly perturbed time delay systems for all ei ∈(0, ∞). A numerical example is given to compare our new results with those in the literature.