EXPERIMENTAL STUDIES OF THE INTERACTION OF TRACTOR DRIVE WHEELS WITH THE SOIL IN THE PLOWED FIELD

The article defines the influence of structural and operational parameters of a machine-tractor unit on changes in the hardness of freshly plowed soil due to deformation and compaction of the soil by wheeled running systems. An experimental model of the effect of pressure in the pneumatic chamber of the wheel, working width and speed of the unit on changes in soil hardness in the area of operation of running systems is obtained. The obtained mathematical models make it possible to predict changes in soil hardness, which makes it possible to reduce the negative impact on the soil of running systems by optimally completing, configuring and selecting the MTU operating mode.

RGB Color Model Analysis for a Simple Structured Polydimethylsiloxane Pneumatic Micromixer

This article reports mixability experiments and their RGB color model analysis for a simple structured micromixer based on the pneumatic-driven membrane in multiple microreagent mixing applications. First, a novel and simple structure consisting of a mixing chamber and a pneumatic chamber is designed and fabricated of polydimethylsiloxane (PDMS) material, which facilitates integration with microfluidic chips. Then, experiment results and their RGB color model about mixing efficiency are investigated. Compared with conventional methods, the RGB color model for mixing results is easy and intuitive. In addition, the designed micromixer operation relies on less external laboratory infrastructure because of its simple structure.

STUDY OF THE DYNAMICS OF PULSE HYDRAULIC MECHANISMS WITH PNEUMATIC STROKE CHAMBER

The paper briefly outlines the state of development of impulse technology. The schemes of hydraulic machines of impulse action with percussion mechanisms of the sixth and seventh classes are presented. The calculation of impulse mechanisms with a pneumatic chamber of the working stroke is given. The physical model of the drain pipeline is presented. Shown is a diagram of the forces acting on the striker during the working stroke. The dependence of the relative energy losses on the ratios of the cross-sectional areas of the working chamber and the drain pipeline is presented. Recommendations are given for the use of a pneumatic accumulator in the drain branch of the pipeline of a pulsed hydraulic mechanism with a pneumatic chamber of the working stroke

A Novel Computer-Controlled Maskless Fabrication Process for Pneumatic Soft Actuators

Template-based and additive manufacturing techniques have demonstrated some fabrication routes for creating pneumatic soft actuators. However, as the complexity and capability of the actuators continue to develop, the limitations of these approaches are becoming evident. These include difficulties for design variations, process speed and resolution, material compatibility and scalability, which hinder and restrict both the possible capabilities of the technology and its transition from research to industry. This body of work presents a computer-controlled, maskless manufacturing process with a different approach to allow for high-speed, low-cost and flexible creation of pneumatic soft actuation networks comprising multi-material construction. This was investigated through a bespoke fabrication platform that provides computer-controlled localised plasma treatment to selectively modify the chemical behaviour on the surface of silicone and polyethylene terephthalate (PET) bodies. The altered surface chemistry facilitated selective bond formation between the treated parts of the surface and, consequently, greater design variation and control over the pneumatic chambers that were formed. Selective treatment patterns allowed nonlinear pneumatic chamber designs to be created, and the strength of bonded silicone structures was shown to facilitate large deformations in the actuators. Furthermore, the different interactions between the plasma and silicone were leveraged to achieve feature sizes of <1 mm and treatment speeds of 20 mm2 per second of exposure. Two multi-material pneumatic soft actuators were then fabricated to demonstrate the potential of the platform as an automated manufacturing route for soft actuators.

Wavetank Tests With a 1:20 Scale Model of a Distensible Tube Device for Wave Power Harnessing in the Azores

The present research focuses on the performance assessment of a wave power system targeted for electrical supply of small communities in the Azores Archipelago. Firstly, the wave power potential and wave directionality in the region is assessed. The data collected points to a device capable of withstanding severe wave climate. The device considered herein incorporates a long rubber tube filled with water, floating head to waves, connected to an oscillating-water-column (OWC) in a shaft. The shaft and power take-off system (PTO) are to be mounted on an offshore jacket platform. By interacting with the incoming ocean waves the tube excites the OWC at its stern, thereafter forcing air in and out of the pneumatic chamber through a turbine-generator set. It has been observed that this device performs as a multiresonant attenuator that couples the tube’s surging motion and longitudinal pressure bulges with the water column oscillations. In our physical model the power take-off’s nonlinear impedance is emulated by means of a set of calibrated orifice plates with different diameters, connecting the pneumatic chamber to the atmosphere. A series of tests have been carried out with a 1:20 scale physical model in wave-tank, undertaken in regular waves that translate to 5 to 9 seconds wave period in full-scale. Two sets of waves were launched, whose wave heights cover a range from 1 to 5 m in real sea conditions, in deep water as well as in intermediate water depths. The pressure inside the chamber and the free-surface displacement in the shaft have been monitored, as well as the wave field. They provide estimates of the extracted power and energy capture efficiency of the system as a function of incident wave period. Scale effects are also addressed by comparison with previous experiments at different scales. Moreover, the amplification coefficient with the tube in position is quantified and compared with typical values for OWCs alone. It is worth noting that the accuracy of the power and energy capture predictions is greatly dependent on the volume flow calculations. Miller’s algorithm for compressible flow has been applied to reduce the uncertainty of volume flow calculations across the PTO orifice. The influences of the resonant operating modes and PTO impedance upon the capture-width are also discussed. The results obtained so far enable us to provide reliable estimates of absorbed power and energy capture efficiency, in prototype dimensions, under the wave climate in the Azores namely at Corvo Island.

Early corset reclination of uncomplicated type А3 comminuted vertebral fractures in the thoracolumbar spine

Objective. To analyze the results of staged preoperative correction of uncomplicated comminuted fractures in the thoracolumbar spine.Material and Methods. Retrospective study included data from 51 patients (33 men and 18 women) 17–35 years old with type A3 spinal injuries without urgent indications for surgery. In preparation for a possible operation, patients received a corset treatment with reclination pneumopelot for 2–3 days.Results. The results were evaluated based on clinical, radiological and CT data. The result after reclination corset treatment was considered good if a restoration of the vertebral height was achieved with its residual deficit of less than 10 % or local wedge shape not more than 10°; satisfactory – with a residual decrease in vertebral body height from 10 to 30 % or in kyphotic deformity from 10 to 20°; and unsatisfactory – with a decrease in body height of more than 30 %, and in kyphotic deformity of more than 20°. With an average decrease in the height of the fractured vertebral body before surgery by 45 % and the local kyphosis magnitude of 27.0° ± 5.5°, the staged reclination provided complete correction of kyphosis in all cases and restoration of the height of the compressed vertebra to a residual deficit of less than 10 % in 78 % of cases. Neurological disorders were not noted.Conclusion. In case of incomplete burst vertebral fractures not complicated by compression of the spinal cord, the method of early (in the first 7 days after the injury) corset treatment with staged fracture reclination by a pneumatic chamber can be effectively used to eliminate local kyphotic deformity and restore the height of fractured vertebra.

MODELING THE INFLUENCE OF THE DESIGN OF THE AERATION DEVICE ON THE UNLOADING OF THE AIR PUMP

It is impossible to imagine the technological process of production of building materials, dry building mixes, reinforced concrete products without an important technological operation of transporting powder materials. Pneumatic chamber pumps are widely used for transporting powder bulk materials and are a mandatory element in the configuration of concrete plants and other mixing equipment. Their advantages are the possibility of full automation of work, reliable protection from atmospheric influences and the necessary sanitary and hygienic working conditions. Therefore, pneumatic chamber pumps are increasingly used for transportation. Compressed air is piped into the pump chamber. The bulk material is saturated with air, the resulting aerated mixture under the influence of excess pressure enters the pipeline and is transported in the specified direction. The disadvantage of pneumatic chamber pumps is the increased consumption of compressed air during transportation. To reduce air consumption, various aeration devices are used. Currently, at the modeling stage, modern software is used to determine the effectiveness of the developed aeration device. The influence of the air flow velocity on the discharge of a pneumatic chamber pump is considered. A design solution for the aeration device of the TA-29 pneumatic chamber pump is proposed.