4results about How to "Lower yield stress" patented technology

The invention relates to the technical field of mine filling, and discloses a high-flux slurry continuous pumping system for underground goaf governance, which comprises a pumping driving unit, a pipe network sensing unit and a central control unit, and is characterized in that sine disturbance signals are superposed at a pumping reference frequency through the central control unit, and pressure disturbance waves carrying phase characteristics are constructed; extracting a phase deviation parameter of the pipe network response waveform, and identifying that the pipeline is in a metastable state deposition stage when the change rate of the phase deviation parameter exceeds a threshold value; outputting a flutter signal to induce interface softening of the sediment, and connecting and outputting an asymmetric pressure pulse of which the rising edge slope is greater than the falling edge slope so as to peel the sediment; according to the method, the abnormal flow resistance is recognized in the deposition stage before dominant fluctuation of the outlet pressure occurs, the instantaneous peak pressure intensity in the blockage clearing process is reduced through a softening and stripping mechanism, and the structural safety of a pipe network under the high-throughput conveying working condition is maintained.

The invention relates to the technical field of grouting materials, in particular to a high-performance prestressed duct grouting material which comprises water, cement, silica fume, mineral powder, limestone powder, a water reducing agent, microbeads, a plastic expanding agent, a suspension stabilizer and a defoaming agent.The cement, the silica fume, the mineral powder, the limestone powder and the microbeads are used for constructing a multi-element mineral admixture system; the powder materials with different particle sizes are mutually filled, so that close accumulation among particles is realized, and the void ratio among the powder is effectively reduced, thereby reducing the water consumption required for filling gaps and improving the compactness and the homogeneity of the slurry; meanwhile, the water reducing agent efficiently disperses cement particles through the steric hindrance effect, the microbeads reduce the friction resistance in the slurry through the spherical ball effect of the microbeads, the plastic viscosity and yield stress of the slurry are remarkably reduced through the combined action of the water reducing agent and the microbeads, and the slurry is endowed with excellent initial fluidity and long-time fluidity maintaining capacity; and it is ensured that the slurry can be rapidly and smoothly filled in the prestressed duct.

The invention belongs to the technical field of mold-free mirror image additive manufacturing of metal components, and relates to a mold-free mirror image additive manufacturing method and system of a metal component. The method comprises the steps that firstly, a geometric center face is determined, then a mirror image printing path is generated, then the double printing tail ends are arranged, the double printing tail ends comprise two pressing rollers used for providing abutting supporting force for each other, and the two pressing rollers are marked as a pressing roller a and a pressing roller b correspondingly; and finally, the double printing tail ends are controlled to synchronously move along the printing path so that the ribbons can be deposited layer by layer from the geometric center to the two sides, and meanwhile the pressing roller b is driven to vibrate in a reciprocating mode in the printing direction. The system comprises the double printing tail ends. The double-printing tail end comprises two pressing rollers used for providing abutting supporting force for each other, the two pressing rollers are marked as a pressing roller a and a pressing roller b respectively, the double-printing tail end further comprises an ultrasonic device, and the ultrasonic device is used for driving the pressing roller b to vibrate in a reciprocating mode in the printing direction. The limitation of an existing heating technology is broken through, and effective metallurgical bonding between layers of the metal ribbons can be achieved.

The present application relates to a kind of carbonization 3D printing concrete mix design method and carbonization 3D printing concrete.The present application is introduced into carbon dioxide to cement-based printing slurry, controls its amount of introduction, while introducing carbon dioxide into cement-based printing slurry, according to the content of carbonation reaction product CaCO3, and the ratio of calcite and aragonite in the required concrete mixture, the amount of magnesium chloride is calculated, magnesium chloride and carbon dioxide are added into cement-based printing slurry at the same time, fully react, finally 3D printing concrete material is prepared.The present application improves the thixotropy of material by the addition of magnesium chloride, the generation of aragonite type calcium carbonate, the constructability of cement slurry is stronger, at the same time, the orientation of nanoscale aragonite fiber is arranged according to the printing direction, has excellent reinforcing and toughening effect, and the bending strength, bending strength and compressive strength are improved.