The author presents a development of computational model of design of ball screws thread. This model is the basis for computer program, which calculates the geometrical features of the thread for precisely given backlashes and contact angles. The program makes it possible to create a data base of a new generation ball screw of quality competitive to foreign ball screws. The modeling allows one to better select the ball screw and to predict its quality in the early stage of design.

In the present study a new energy theorem is proposed, "The two actionstheorem", which is valid in linear elastostatic problems. A new formalism concerning the works done by the external actions is introduced. Known energy theorems are proved using the proposed two-actions theorem. A composite materials problem is confronted in terms of the two actions theorem and energy relations are formulated. Finally, it is presented a study on the problems of a composed two material hollow cylinder under internal and external pressure, and of stretching of an infinite plate with an inserted elastic disc of a different material. The proposed energy relations are verified in these applications.

The paper presents an original design of a single compression machine for combustion study. The principle of operation is based an old concept, utilizing the inertia energy of a flywheel to accelerate the crank mechanism and the attached piston to compress rapidly the combustible mixture in the combustion chamber. A square piston geometry was adopted to allow visualization of the compression and combustion processes in directions perpendicular to the cylinder axis. To avoid the extensive scratching of glass walls by the moving piston, a special multi-action clutch-brake unit was used; this facilitates coupling of the flywheel with the crank mechanism during the single piston stroke and subsequent immediate uncoupling and fast stopping of the piston. The whole operating cycle can be completed within no more than two revolutions of the crankshaft. The design details of the machine, its acceleration characteristics and a sample of the visualized combustion process are presented.

The paper presents a new kind of vibrator, called the intelligent vibrator, which is an integrated set of two inert vibrators supplied by asynchronous squirrel-cage motors, equipped with digital control system, the readout system of the position of unbalanced masses, and inverter supply system. The paper presents a model of the prototype of the machine and exemplary run-times.

The advance of technical state criteria for elements of mining hoists demands a basic strength-fatigue analysis where the real values of loads and the real time function of the load variability could be used. That problem concerns also the suspension gear of skip and balance ropes, where fatigue durability should be considered as time function related to the hoist facility type. Such objective can not be achieved without comprehensive study of the dynamics of processes both in the regular operation of the facility and in its emergency states. In this work the author presents some considerations, that are however, limited to the analysis of dynamic phenomena observed in the condition of the emergency braking of the hoist facility. The results were verified by load measurements taken for some elements of the analysed real object system.

In the paper, the authors discuss the possibility to apply the "Nodalised Beam" method for vibroinsulation of manually operated tools. They indicate the difficulties in applying the original method for this purpose. On the bases of the reciprocity principle, the authors propose a method for modifying the system that allows them to avoid the mentioned disadvantages. Equations derived for the modified system that makes it possible to define the position of nodal points. The relations were verified at a test station. Furthermore, a method of tuning the system was proposed.

The measurement of lift and drag forces on the omithopter model with flapping wings was carried out in the wind tunnel. The wing movement had two degrees of freedom: flapping (around the longitudinal axis of the model) and feathering (around the wing axis). Forces were measured in static case - as averaged values during many cycles of movement, and in dynamic case - as unsteady forces captured in function of the flapping phase. The magnitudes of the aerodynamic coefficients of lift and drag were calculated.

A flow around an NACA00 12 airfoil at special transonic flow conditions, characterised by damped oscillations of the main flow velocity, was investigated experimentally. On the basic of pressure measurements and flow visualisation, the time depending airfoil loading was reconstructed. Results, presented for a wide range of angle of attack ( a =Q-;-10°), show that during the excitation the normal aerodynamic force behaviour significantly differs from that of quasi- steady conditions. The pressure distributions on the airfoil surface depend on Mach number of the main flow as well on the phase of oscillation (deceleration or acceleration of the main flow velocity). The influence of the air humidity on the pressure distribution, normal aerodynamic force and centre of pressure is also considered.

The paper presents the results of simulation and research of antilock braking systems (ABS) carried out on the fast rotating drum stand with flywheels. The model of the vehicle-drum stand system was presented. The influence of car suspension and tyre parameters during braking with ABS on vehicle vibrations was analysed. Theoretical analyses of the simulations were verified during car tests on a prototype drum stand. The results of braking tests for passenger car on the homogeneous surface and on the surface with changed adhesion coefficient were presented. Qualitative criteria for diagnostic evaluation of ABS operation were proposed.

The knowledge of heat transfer processes inside a compressor cylinder is very important from the technical point of view. An adiabatic model of compression can be assumed in theoretical investigations. In practice, the compressor cylinder is always coo_led to decrease the compression work and to reduce the final temperature of a medium being compressed. This paper presents applications of the NANMAC eroding thermocouples to record temperature time histories of surfaces taking a part in the heat exchange during the compression cycle. The thermocouple construction and junction technology ensure a very small thermal inertia. The response time is of the order of I O μs. The eroding thermocouple was used to measure an instantaneous surface temperature of a plate closing the cylinder and the piston head temperature. Because of very low value of the thermoelectric signal, an amplifier of a very high gain and reasonable bandwidth was required. This induced noise of significant amplitude. The recorded experimental data were numerically processed in order to exclude the noise of measurement circuits, and then the data were used to calculate local heat flux rates. To ensure repeatability of the measurements, the experiments were canied out in a specially prepared set-up allowing single compression cycles to be performed.

The authors present the optimisation procedure and results, applied to the system discussed in part I. This procedure utilises a "fixed variables" method from the group of "search methods". The optimisation is related to the specific turbocharged engine STAR T3 70 for which necessary construction data and experimental measurements were available. Calculation results, however, are based mainly on the computer simulation of time dependant flows in the inlet and exhaust systems of this engine. They show that the presented method, after necessary improvements and the use of more advanced optimisation procedures, could represent an additional and attractive tool, which might be used by designers of such systems.