No abstract

Aerogel fibers are thermally insulating and can be woven, so they are expected to form a new generation of smart textiles that can efficiently reduce heat consumption. However, producing continuous aerogel fibers that have the necessary strength and toughness to be woven remains a great challenge. Herein, with the aid of freeze‐thaw treatment of poly(vinyl alcohol) (PVA) solution and freeze‐spinning technology, continuous PVA aerogel fibers with an aligned porous morphology are prepared in a large‐scale. Freeze–thaw treatment greatly contributes to improving the spinnability of the spinning dope of aerogel fibers, which leads to the formation of the continuous fibers. Remarkably, through this process the aerogel fibers achieve ultraflexible and ultrastrong features, which results in excellent weaving ability, as well as attractive mechanical properties that benefit from the cross‐linking of PVA molecular chains with the aligned porous structure. More importantly, a textile woven with the special porous structure aerogel fibers shows extraordinary thermal insulation (thermal conductivity as low as 0.026 W m−1 K−1) and infrared stealth. This study illustrates a promising direction for the design of next generation, wearable, intelligent materials that have great potential for personal thermal management applications.

Recently, airflow sensors have been paid great attention due to their unique characteristics. However, the preparation of high-performance airflow sensors in an extraordinarily simple, controllable and cost-effective method remains a...

The endless diamond wire saw was developed using complex electroplating method. The sawing process on granite was experimented. The effects of diamond grain size, feed load, wire speed, and granite properties on sawing process were investigated. It is proved that the edges of sawing slot of granite were regulative and the cutting surfaces were smooth. The cutting efficiency could be improved by increasing the diamond grain size, wire speed, and feed load. However the increase of the feed load would induce higher tangential cutting force, and the case of the effect of wire speed was reversed.

Although it is unexpected, pure mineral oils or machinery oils are still widely used as cutting fluids in many cases and areas. In this paper, the performance of extreme pressure (EP) additives, including Chlorinated Paraffin, Acid phosphate, and ZnDDP, was evaluated with the index of material removal ability and specimen hardness drop by the use of grinding test method. A micro-structure model of specimen surface layer under wet grinding conditions was proposed, which could be used for explaining the boundary lubrication mechanism of cutting fluids. The characteristic was revealed that organizational structure and shearing strength of specimen surface layer at wet grinding conditions descended along the out normal line direction of the specimen surface. Based on experimental research, high-performance oil-based cutting fluids were developed and tested in several machine-building factories. The fluids one also expected to be applied in the processing of natural rock materials, during which the friction between diamond tools and rock is the main barrier to increase processing efficiency.