Agnieszka Dąbrowska

Experimental Research on Directional Stability of Articulated Tractors

Articulated tractors are wide available on the construction equipment market and have a lot of unique advantages not accessible in case of Ackerman steering system or truck-mounted tools. The only unsolved problem is their poor directional stability which significantly limits the speed of operation and work efficiency. This paper investigates the phenomenon of directional stability loss and indicates main reasons for its appearance by means of experimental research. Moreover, conducted tests, acquired results and their analysis could be a basis for future works on stabilizing system supporting the driver of an articulated tractor or enabling operation in remote control mode.

One-Step Combustion Synthesis of Novel Nanocarbons via Magnesiothermic Reduction of Carbon-Containing Oxidants

The aim of this work was to transform carbon-containing ammonium oxalate, (NH4)2C2O4, and ammonium acetate, NH4CH3CO2, into 3D graphene-like carbon nanomaterials via magnesiothermic reduction. Both raw and purified products were characterized by XRD, SEM, TGA, and Raman spectra. The conversion of the initial amount of carbon (in salts) into solid carbon (in purified product) varied between 8.5% (for oxalate) and 90.0% (for acetate). The XRD results confirmed the absence of starting salts in the raw products (MgO and C). The purified product was found to contain largely the turbostratic carbon forming a petal-like 3D graphene material. The application potential of synthesized materials was demonstrated on the example of the removal of 4-chlorophenol from its aqueous solution.

Preparation of SiCw-ZTA Composites by Two-Step Sintering or Spark Plasma Sintering

Alumina materials are widely used in the industry as cutting tool inserts. In order to improve mechanical properties of the Al2O3 matrix, different reinforcing phases are introduced. In the presented work, reinforcements in the form of ZrO2 particles and SiC nanofibres have been used. ZTA-SiC composites were obtained from 0.5%MgO-20%(3Y2O3)ZrO2-79.5%Al2O3 powder and 15% of SiC whiskers. Tested materials have been prepared by means of the two-step sintering (TSS) and spark plasma sintering (SPS). TSS method permits to obtain dense materials with fine-grained microstructure. TSS has been carried out for two different sintering times: 1 hour 20 minutes and 8 hours. Due to the reactivity of the components, the SPS method has been used to shorten sintering times. SPS has been performed at two different temperatures: 1500 °C and 1550 °C.