Mm In Bending Research Articles

Влияние рецептурных факторов на прочностные свойства тяжелых сталефибробетонов

Today, steel fibre is one of the most promising components used to produce fibre reinforced con-crete. To improve the mechanical properties of heavyweight steel fibre reinforced concrete, the influ-ence of recipe factors, namely the percentage of fibre reinforcement and the fibre length, on these properties was studied. 18 series of reference samples of a standard size were manufactured and tested: 27 cubes with dimensions of 100x100x100 mm for compression tests and 27 prisms with di-mensions of 100x100x400 mm for bending under tension test. We calculated mechanical strength characteristics depending on the recipe factor. The calculations were performed using a numerical ex-perimental design (full factorial experiment 2k). Based on the obtained results, it can be concluded that the utilisation of steel fibre with a fibre length of 30 mm or the percentage of three-dimensional rein-forcement of 1.5% is the most effective.

Design of microgrippers based on amorphous-crystalline TiNiCu alloy with two-way shape memory

Functional layered composites of the shape memory alloys are recently recognized as promising basic active element for microsystem technology and microrobotics. Amorphous-crystalline TiNiCu alloy ribbons at around 40 μm of thickness with an interface separating the amorphous and crystalline phases into layers were produced by melt spinning technique. It is shown that a decrease in the cooling rate of the melt from 8.9·105 to 4.2·105 K/s leads to an increase in the thickness of the crystalline layer from 2 to 10 μm. The ratio of the thicknesses of the amorphous dam and crystalline dcr layers was also varied by an electrochemical polishing method. The composite ribbons have exhibited the two-way shape memory effect (TWSME) of thermal induced bending deformation without additional thermomechanical training. It was established that when the ratio dcr/dam is changed from 0.06 to 0.35, the minimum bending radius of the ribbon decreases from 37.1 to 6.3 mm, and the maximum reversible strain increases by 0.05% to 0.27%. The minimum time of the shape recovery of the composite ribbons when heated by an electric current pulse was 14 ms, and the force generated by the ribbon with a length of 3 mm in bending reached 1.2 mN. A series of the microgrippers (microtweezers) were fabricated on the basis of the composite ribbons with TWSME. Complete technological process of manipulating graphite filaments with a diameter of 5 to 25 μm using developed microgrippers was demonstrated.

A high-performance and flexible thermoelectric generator based on the solution-processed composites of reduced graphene oxide nanosheets and bismuth telluride nanoplates.

The fabrication of a flexible thermoelectric generator (TEG) with both high power output and good flexibility has drawn considerable attention. Solution-processed inorganic nanocrystals have good processibility in interface to retain excellent electrical properties of nanocrystals and can be processed into thin films on a flexible substrate by an easy scale-up printing or coating method. However, a high-performance TEG device based on inorganic solution-processed materials also poses challenges when it comes to flexibility of the whole device. Herein, flexible planar TEG devices are fabricated by printing an ink mixture comprising solution-processed bismuth telluride (Bi2Te3) nanoplates with reduced-graphene oxide (rGO) nanosheets onto flexible polyimide substrates. The interface treatment by hot ethylenediamine and the appropriate amount of rGO contribute to the high electrical properties of the material. Also, when rGO nanosheets of 1% mass ratio are added, the optimum power output of the corresponding rGO/Bi2Te3 TEG device with six elements reaches ∼1.72 μW at a temperature difference of 20 K. Moreover, owing to the contribution from flexible rGO nanosheets, the suitable thickness of each element, and the artful connection of elements with a soft copper wire in the devices, the 1% rGO/Bi2Te3 TEG device was found to be robust, and its electrical resistance merely changes by 2% after bending 1000 cycles on 5 mm in bending. These inorganic-based TEGs with both high performance and good flexibility will promote the development of new generation energy devices in the field of flexible electronics.

Novel Balloon Surface Scanning Device for Intraoperative Breast Endomicroscopy.

Recent advances in fluorescence confocal endomicroscopy have allowed real-time identification of residual tumour cells on the walls of the cavity left by breast conserving surgery. However, it is difficult to systematically survey the surgical site because of the small imaging field-of-view of these probes, compounded by tissue deformation and inconsistent probe-tissue contact when operated manually. Therefore, a new robotized scanning device is required for controlled, large area scanning and mosaicing. This paper presents a robotic scanning probe with an inflatable balloon, providing stable cavity scanning over undulating surfaces. It has a compact design, with an outer diameter of 4mm and a working channel of 2.2mm, suitable for a leached flexible fibre bundle endomicroscope probe. With the probe inserted, the tip positioning accuracy measured to be 0.26mm for bending and 0.17mm for rotational motions. Large area scanning was achieved (25-35mm(2)) and the experimental results demonstrate the potential clinical value of the device for intraoperative cavity tumour margin evaluation.