Quality control of adjustment of clearances of ball bearing supports, dynamic devices rotor-type, according to parameters of acoustic emission signals

The article is devoted to increasing the bearing life of dynamic rotary-type machines by controlling the uniformity of the distribution of the value of the preliminary axial load acting on the rolling bearings of the rotation axis of the power unit. The possibility of monitoring the axial load using acoustic emission (AE) signals is considered. The results of experimental studies of the kinematics of the ball movement relative to other bearing parts, depending on the tightening torque of bolted joints, estimated by the parameters of AE signals, are presented.

Evaluating the Vertical Extension Module of a Building with Installed Rotary Dampers at Joints

In this study, the shape of a vertical expansion module with a rotary-type damping device is proposed. The external energy dissipation capacity is confirmed through experiments and the performance of the module is simulated. It can be easily applied to high-rise structures, as the module is directly supported by the bearing walls without the need for a separate base system. Additionally, as the damper can be replaced, it is possible to enhance seismic performance even after construction. The simulation results show that the rotary-type damper is more effective in reducing the displacement, shear force, and moment than free and fixed joints. In the pushover analysis of a system modeled using the moment hinge of the rotary damper of the joint, the best response reduction effect is obtained when the yield moment of the hinge is defined as 1% of the frame plastic moment. As a result of the analysis of the multi-degree-of-freedom system considering a harmonic load, we determined that it is efficient for the hinge to yield after the displacement, and the acceleration response of the resonant structure reaches steady state during the installation. In the multi-degree-of-freedom system with slab joints added to the analytical model, the displacement response decreased gradually as the natural period of the structure decreased and the joint increased. This provides evidence that the damper does not affect the overall behavior of the structure. The most important design factor of the rotary-type friction damper, shown through the experiment, is the relationship between the frictional surface and the tightening force of the bolt.

Improvement of the Chimney Effect in Stack Ventilation

The article is focused on the airflow in a ventilation system in a building. The work examines the methods which enhance the chimney effect. In this paper, three cases with different chimneys were analyzed for the full-scale experiment. These cases were characterized by different geometrical and material parameters, leading to differences in the intensity of the ventilation airflow. The common denominator of the cases was the room with the air inlet and outlet to the ventilation system. The differences between the experimental cases concerned the chimney canal itself, and more precisely its part protruding above the roof slope. The first experimental case concerned a ventilation canal made in a traditional way, from solid ceramic brick. The second experimental case concerned the part that led out above the roof slope with a transparent barrier, called a solar chimney. In the third experimental case, a rotary type of chimney cap was installed on the chimney to improve the efficiency of stack ventilation. All these cases were used to determine the performance of natural ventilation—Air Change per Hour (CH). Additionally, the paper presents a technical and economic comparison of the solutions used.

Exposure Assessment of Airborne Bacteria Emitted from Swine Manure Composting Plant

This study was performed to investigate the distribution characteristics of airborne bacteria emitted from swine manure composting plants. The types of swine manure composting plants selected for the survey in this study were as follows: screw type, rotary type, and natural dry type. Mean levels of airborne bacteria in swine manure composting plants were 7428 (±1024) CFU m−3 for the screw type, 3246 (±1407) CFU m−3 for the rotary type, and 5232 (±1217) CFU m−3 for the natural dry type, respectively. Based on the results obtained from this study, the swine manure composting plant operated by screw type showed the highest concentration of airborne bacteria, followed by the natural dry type and rotary type. The monthly concentration of airborne bacteria was the highest in August and the lowest in November, regardless of the type of swine manure composting plant. The respirable size of airborne bacteria accounted for about 50% of the total. The ratio of respirable to the total quantity of airborne bacteria was 50%. The correlation relationships between airborne bacteria and environmental factors (temperature, relative humidity, particulate matters, and odor) were not found to be significant in the swine manure composting plants. The predominant genera of airborne bacteria identified were Micrococcus spp., Staphylococcus spp., Escherichia(E-coli) spp., Enterococcus spp., and Enterobacteriaceae spp.

Drudgery reduction in operation of cleaner-cum-grader: An ergonomic intervention

A pedal-operated cleaner-cum-grader having common bicycle chain-sprocket mechanism to get the speeds of 240 and 720 rpm of eccentric shaft and blower shaft, respectively for the desired cleaning/grading of grains was developed earlier by CIAE, Bhopal. Also, in order to utilize the human energy in more efficient way through pedalling mode, CIAE has recently developed a dynapod. The dynapod is a pedal operated rotary device, which can be used as an interface between human worker and any rotary-type machine. The developed dynapod was used to operate the cleaner-cum-grader to assess the drudgery reduction in its operation in comparison to original pedalling mechanism. The dynapod was interfaced with the cleaner-cum-grader by carrying out minor modifications in the original unit. Eight male agricultural workers with mean stature and weight as 168.4 cm and 54.4 kg, respectively participated in the study. The cleaner-cum-grader was used for cleaning and grading of soybean grains. Heart rate of the workers was measured during operation of cleaner-cum-grader using the dynapod as well as the original pedalling mechanism. Mean working heart rate during operation of machine with original pedalling mechanism was 114 beats min-1 as against 108 beats min-1 in case of pedalling with dynapod. The work pulse (ÄHR) with the original pedalling mechanism was 35 beats min-1 as against 29 beats min-1 during pedalling with dynapod. The output capacity of the machine increased from 303 kg h-1 in case of original pedalling mechanism to 345 kg h-1 with dynapod. Considering the cardiac cost as well as output of the machine, the drudgery reduction by using dynapod with cleaner-cum-grader was about 25.4% as compared to the original pedalling mechanism.

Inertial Piezoelectric Rotary Motor Based on Low Profile Stator with Trapezoidal Waveguides

Results of numerical and experimental investigations of a novel inertial piezoelectric rotary type motor based on a low profile stator with trapezoidal waveguides. The proposed motor has a simple design and is well scalable. Moreover, the proposed design of the motor allows mount it on a printed circuit board and use it in a small-size mobile positioning and actuating systems. The structure of the stator is based on a square type hollowed steel frame with four straight trapezoidal waveguides that are used to transfer vibrations of the stator to the rotation of the rotor. Piezo ceramic plates are glued on both sides of the stator. The thickness of the assembled stator is 0.9 mm, while the total area needed for stator mounting does not exceed 625 mm2. The driving of the rotor is based on the stick-slip principle, which is induced by excitation of the second in-plane bending mode of the four bimorph plates applying two saw tooth waveform signals with a phase difference by π. The numerical and experimental investigation was carried out to validate the operation principle of the motor and to measure the mechanical and electrical characteristics. The maximum angular rotation speed of 1304 RPM was achieved at a resonance frequency of 44.81 kHz when a preload of a 7.35mN was applied.

Technical hemp harvesting cutting machine parameters and operation modes calculation

In the article, a promising scheme of a rotary type apparatus for a non-support cut of technical hemp is proposed. The main design parameters of working bodies are defined (diameter of the cutting disc, location of the cutting segments, width of the device). The operating modes of the cutting device are calculated (cutting speed, rotational speed and angular speed of the blade, torque, power applied to the drive). The research results will be used to create working bodies for harvesting technical hemp.

Analisa Pipa Heat Exchanger (Cooling Tube) Bervariasi Pada Turbine Guide Bearing Pembangkit Listrik Tenaga Air Siguragura

A heat exchanger is a medium used to produce heat transfer from one fluid to another. Heat Exchanger can be used to raise the temperature or as a heater (regenerator) or lower the temperature or as a coolant (recuperator) depending on the view of heat transfer that occurs. Heat exchangers have been widely used in industries such as the chemical industry, paper industry, power plants, and other industries. In the example, each machine unit uses a heat exchanger media (especially rotary type machines) to keep the bearing temperature in normal temperature even though the unit is operated continuously or continuously. This study will analyze the temperature drop that occurs when the length of the heat exchanger pipe is added to the turbine guide bearing of PLTA Siguragura. From the research results, the maximum temperature on the guide bearing cooling tube reaches 47.3 [° C], the overall heat transfer coefficient on the guide bearing cooling tube is 98.87 [W / m²ºC], ∆Tmin on the guide bearing cooling tube installed (with 2 layers) is 14.1 [° C] and ∆Tmin which can be achieved with a cross-sectional area of ​​5.73 [m²] is 6.63 [° C]