The proposed paper discusses the design and characterization of a soft miniature Magneto-Rheological (MR) shock absorber. In particular, the final application considered for the insertion of the designed devices is a controllable variable stiffness sole for patients with foot neuropathy. Such application imposes particularly challenging constraints in terms of miniaturization (cross-sectional area ≤ 1.5 cm2, height ≤ 25 mm) and high sustainable loads (normal loads up to 60 N and shear stresses at the foot/device interface up to 80 kPa) while ensuring moderate to low level of power consumption. Initial design considerations are done to introduce and justify the chosen novel configuration of soft shock absorber embedding a MR valve as the core control element. Successively, the dimensioning of two different MR valves typologies is discussed. In particular, for each configuration two design scenarios are evaluated and consequently two sets of valves satisfying different specifications are manufactured. The obtained prototypes result in miniature modules (external diam. ≤ 15 mm, overall height ≤ 30 mm) with low power consumption (from a minimum of 63 mW to a max. of 110 mW) and able to sustain a load up to 65 N. Finally, experimental sessions are performed to test the behaviour of the realized shock absorbers and results are presented.

Zoo is a didactic assembly induced in the system of urban greenery. It has an educational, entertainment, and scientific values. This kind of gardens, directly derived from tradition of baroque menagerie, were created from the mid-18th century. Their greatest development occured since the 2nd half of 19th century and the 20th century. The article is regarding issues of the miniature zoo in Upper Silesia created before World War II. They will be presented their resource, state of preservation and the characteristics of selected examples.

Compact radiators with circular polarization are important components of modern mobile communication systems. Their design is a challenging process which requires maintaining simultaneous control over several performance figures but also the structure size. In this work, a novel design framework for multi-stage constrained miniaturization of antennas with circular polarization is presented. The method involves se- quential optimization of the radiator in respect of selected performance figures and, eventually, the size. Optimizations are performed with iteratively increased number of design constraints. Numerical efficiency of the method is ensured using a fast local-search algorithm embedded in a trust-region framework. The proposed design framework is demonstrated using a compact planar radiator with circular polarization. The optimized antenna is characterized by a small size of 271 mm2 with 37% and 47% bandwidths in respect of 10 dB return loss and 3 dB axial ratio, respectively. The structure is benchmarked against the state-of-the-art circular polarization antennas. Numerical results are confirmed by measurements of the fabricated antenna prototype.

In this work, authors investigated the effect of the Depth of Field (DoF) reduction, arising when the acquisition of small objects is carried out with a photogrammetry-based system using a Digital Single Lens Reflex (DSLR) camera and the structure from motion (SfM) algorithm. This kind of measuring instrument is very promising for industrial metrology according to the paradigms of the fourth industrial revolution. However, when increasing the magnification level, necessary for the reconstruction of sub-millimetric features, there is a corresponding decrease of the DoF, leading to possible effects on the reconstruction accuracy. Thus, the effect of the DoF reduction was analysed through the reconstruction of a well-known artefact: the step gauge. The analysis was conducted considering the theory behind the DoF concept, the analysis of the 2D images, input of photogrammetric reconstruction and, finally, the results in terms of dimensional verification of the reconstructed step gauge.

The rod specimens were produced from Pr9Fe50 + xCo13Zr1Nb4B23 – x (x = 0, 5, 8) alloys using the suction-casting technique. Subsequent devitrification annealing of those samples resulted in the change of their phase structure and magnetic properties. For annealed specimens of all investigated compositions, the Rietveld analyses of X-ray diffractions have shown the presence of three crystalline phases: the hard magnetic Pr2Fe11.2Co2.8B, soft magnetic α-Fe, and paramagnetic Pr1 + xFe4B4, which have precipitated within the amorphous matrix. This technique allowed us to determine the weight fractions of constituent phases. Furthermore, the microstructural changes with the alloy composition were observed. Magnetic measurements of annealed rods allowed us to calculate the switching field distributions (SFD) and δM plots in order to determine the strength and character of magnetic interactions between grains of constituent phases.