The Development of Controlled Orientation of Fibres in SFRC

The article is focused on finding the possibility of the controlled orientation of fibres in fibre reinforced concrete constructions. This is because the controlled orientation of the fibres can contribute to the improvement of some properties of fibre reinforced concrete. The research is based on the experimental investigation of orientation control–rotation of fibres in a transparent matrix representing concrete replacement. From the conceptual model, the article continues with experimentation, data analysis and comparison of conclusions. During the experiment, a mechanical tool was developed and monitored to guide the fibres. The main monitored parameters of the levelling tool were the tips dimensions and the distance between them. The experiment results show the possibility of achieving a higher orientation of the fibres around one axis and suitable parameters of a mechanical tool.

AUTOMATED CONTROL SYSTEM OF CHILDREN’S CAROUSEL

Automated control system for children's carousel has been developed and manufactured. Control cabinet for children's carousel has been designed and control program for programmable logic controller has been written. Control system increases operation reliability of children's carousel and secures ability to control rotation speed of racks.

REACTION OF DOMESTIC AND FOREIGN POTATO VARIETIES TO THE USE OF GREEN MANURE

The article presents the productivity and quality of domestic and foreign potato varieties when grown in crop rotations with shortened rotation. As a green manure crop on control (permanent landing) we used mustard white after harvesting potatoes, in a two-field crop rotation-vicooat mixture, and in a three-field-rotationannual clover. The yield of potatoes of different varieties in crop rotations was significantly higher than in the control rotation. The prevalence of diseases in plantings and tubers on the background of 100% saturation was 1.5-2 times higher than in crop rotation. Plowing of green manure mass into the soil contributed to the containment of potato diseases. The most economically profitable are cultivation of a domestic variety Kolobok in crop rotations. Economic efficiency of growing potatoes in crop rotations with different degrees of saturation shows us that, on average, for 3 years, the most economically profitable cultivation of domestic variety Kolobok in the variants of 2 and 3 - full crop rotations, permanent culture are less effective. For example, the profit in the 2-pole crop rotation for the variety Kolobok amounted to 143 thousand rubles/ha, and in the 3-pole 193 thousand. rubles / ha, permanent culture-74 thousand rubles / ha (2-2. 5 times less). According to the variety Breeze, these indicators amounted to 133, 183 and 70 thousand rubles/ha, respectively.Cultivation of the Saturn variety was even less profitable, namely-112, 163 and 37 thousand rubles / ha, respectively.

Experimental Validation of a Special Locking Drum Brake for Robotic Applications

The paper presents the development of a novel type of drum brake capable of locking a joint exploiting the effect of self excitation characteristic of this type of brake. A theoretical analysis based on the Reye assumption on wear is first presented, were conditions for self excitement are determined. An initial version of the brake was designed and tested, but it was soon discovered that actuation with solenoids was not appropriate. A second version was then developed where solenoids were replaced by a small motor and reducer placed inside the brake itself, but the resulting drum was too big for the application. Finally a version were the motor and reducer were placed outside the drum was designed. An ad hoc experimental test bed was built using a Maxon motor to control rotation and toque of the drum and to allow an initial wear of the ferodo in order to obtain compliant surfaces. Finally an electronic control of the brakes has been developed.

The Influence of Gain Control Rotation on Nonlinear Distortion in Hearing Aids

To investigate the relationship of nonlinear distortion to gain control position, 35 hearing aids of differing makes and models were examined. Distortion levels were observed at eight gain settings, each of which represented 12.5% of the total available rotation of the gain control. Distortion was measured at 500, 700, 900 Hz, and at the frequency of maximum distortion. The results support previous findings of high nonlinear distortion at or near maximum acoustic gain in some hearing aids. In order to obtain reductions in the distortion levels observed at full-on gain, extensive counter rotations of the gain control dial frequently were necessary.