Identification of biomechanical properties of temporomandibular discs

Purpose of the Paper. The study was aimed at identifying the biomechanical properties of the temporomandibular disc. Material. Experimental and model tests were conducted on ten fresh porcine temporomandibular joint discs. The average thickness of disc tissue was, accordingly, 2.77 mm for the anterior zone, 3.98 mm for the posterior, and 1.54 mm for the intermediate. The selection of research material in the form of porcine discs was due to the similarity to human discs. Methods. Discs were loaded in cycles, a temporary course with the amplitude 3 N and frequency 0.07 Hz, and growth in the load was 1 N/s. The selection of load frequency was due to real conditions of temporomandibular joint functioning during mastication. The necessary experimental research was conducted on a testing machine with a measurement range of 2.5 kN. Results. The obtained numeric calculation results indicate that the number of load cycles has a decisive impact on the limitation of energy dispersion capacity through disc tissue. This phenomenon was observed in all the studies on the disc areas. Along with the growth in load cycles, discs are stiffened, and the most significant stiffness was observed in the intermediate area. Conclusions. Based on the conducted research, it should be concluded that excessive load affecting temporomandibular joints caused by the act of mastication and occlusal forces generated during parafunction and in people with defined long-term bruxism has crucial importance on biomechanical disc properties and hence the course of temporomandibular joint conditions

"Movable platform" - the idea and energy consumption

This paper presents the application of the concept of moving sidewalks at railway stations (the movable platform) including the calculation of electricity consumption. Particular focus was placed on issue of energy profit and loss in two stages - through the loss (consumption) of energy by using a moving sidewalk at a railway station platform and the profit (reduced consumption) of energy, by the lack of having to start the train, that supports movable platform, from the initial speed of 0 km/h

Impulse excitation diagram as a tool to achieve high energy orbits

The paper presents the application of a new impulse excitation diagram (IED) to help realize high-energy orbits in nonlinear energy harvesting systems. In the case of non-linearity, we can deal with the occurrence of coexisting solutions and the proposed diagram allows for the use of the impulse excitation method in order to change the solution. For this purpose, the author's IED diagram was presented to determine the characteristics, duration and moment of initiation of the external disturbing impulse in order to jump to another orbit. An application example is the quasizero energy harvester and two different impulse characteristics.Comment: 5 pages, 4 figure

Dynamic response of the spherical pendulum subjected to horizontal Lissajous excitation

This paper examines the oscillations of a spherical pendulum with horizontal Lissajous excitation. The pendulum has two degrees of freedom: a rotational angle defined in the horizontal plane and an inclination angle defined by the pendulum with respect to the vertical z axis. The results of numerical simulations are illustrated with the mathematical model in the form of multi-colored maps of the largest Lyapunov exponent. The graphical images of geometrical structures of the attractors placed on Poincaré cross sections are shown against the maps of the resolution density of the trajectory points passing through a control plane. Drawn for a steady-state, the graphical images of the trajectory of a tip mass are shown in a three-dimensional space. The obtained trajectories of the moving tip mass are referred to a constructed bifurcation diagram

Application of electronic dental dynamometer in biomechanics

The paper presents a microprocessor force recorder, whose design allows the measurement of occlusal forces on a continuous basis with a maximum frequency of 250 Hz. The electronic dental dynamometer records the results of clinical trials in the form of graphic images and text files which are presented directly onto the computer. The recorded results can be processed digitally, as well as compared with other measurements, resulting in the ability to monitor the progress and potential advances in the treatment of masticatory organ diseases. An important advantage of the proposed solution is the simple and intuitive design. In addition, the dynamometer requires no power coming directly from the electricity network, as it is powered through a 5 V USB port. This feature not only determines the comfort of use, but also the safety as the voltage does not pose a risk to the patient during examination. The results recorded during clinical trials using the electronic dental dynamometer are consistent with those obtained using a calibrated mechanical dental dynamometer

INFLUENCE OF CHANGES IN THE WORKING TEMPERATURE OF FLEXIBLE COUPLINGS ON THEIR STIFFNESS CHARACTERISTICS

This article compares flexible couplings of the spider-type insert, and the tire-type insert. The influences of the volume and hardness of the elastomeric connector on the characteristics of this type of coupling, as well as the course of the change of the stiffness coefficient as a result of changes in the operating temperature, are presented. In drive systems, flexible couplings undergo very frequent changes within a wide range of operating temperatures, which causes a change in the dynamic parameters of the flexible couplings during operation

Application of electronic dental dynamometer in biomechanics

The paper presents a microprocessor force recorder, whose design allows the measurement of occlusal forces on a continuous basis with a maximum frequency of 250 Hz. The electronic dental dynamometer records the results of clinical trials in the form of graphic images and text files which are presented directly onto the computer. The recorded results can be processed digitally, as well as compared with other measurements, resulting in the ability to monitor the progress and potential advances in the treatment of masticatory organ diseases. An important advantage of the proposed solution is the simple and intuitive design. In addition, the dynamometer requires no power coming directly from the electricity network, as it is powered through a 5 V USB port. This feature not only determines the comfort of use, but also the safety as the voltage does not pose a risk to the patient during examination. The results recorded during clinical trials using the electronic dental dynamometer are consistent with those obtained using a calibrated mechanical dental dynamometer

Numerical identification of the overhead travelling crane’s dynamic factor caused by lifting the load off the ground

Overhead travelling cranes work with intermittent motion, and therefore are most exposed to dynamic loads. In steel constructions, as a result of load pick up from the ground, vibrations of various degrees of intensity are induced, which should be included in crane design. These loads affect both the hoisting mechanisms and load-carrying structures. The aim of this study is the formulation of a phenomenological model of an overhead travelling crane enabling the identification of dynamic factors caused by lifting the load off the ground. The object of the study was 107 overhead travelling cranes with lifting capacities from 5 to 50 tones, designed in the Centre for Research and Development of Cranes and Transport Equipment “Detrans” in Bytom and produced in Poland in the period 1970-2005. Cranes were classified according to the stiffness classes proposed in European standards for crane safety. In this paper, computer simulations are carried out on the basis of a phenomenological model with four degrees of freedom, three of them corresponding to the crane’s structure and one to the hoisted load. The model also allows assumption of the variable stiffness and damping of the steel rope during its shortening. The values of the dynamic factors refer to the various design and dynamic parameters of overhead travelling cranes, formulating appropriate conclusions

Numerical identification of the overhead travelling crane’s dynamic factor caused by lifting the load off the ground

Overhead travelling cranes work with intermittent motion, and therefore are most exposed to dynamic loads. In steel constructions, as a result of load pick up from the ground, vibrations of various degrees of intensity are induced, which should be included in crane design. These loads affect both the hoisting mechanisms and load-carrying structures. The aim of this study is the formulation of a phenomenological model of an overhead travelling crane enabling the identification of dynamic factors caused by lifting the load off the ground. The object of the study was 107 overhead travelling cranes with lifting capacities from 5 to 50 tones, designed in the Centre for Research and Development of Cranes and Transport Equipment “Detrans” in Bytom and produced in Poland in the period 1970-2005. Cranes were classified according to the stiffness classes proposed in European standards for crane safety. In this paper, computer simulations are carried out on the basis of a phenomenological model with four degrees of freedom, three of them corresponding to the crane’s structure and one to the hoisted load. The model also allows assumption of the variable stiffness and damping of the steel rope during its shortening. The values of the dynamic factors refer to the various design and dynamic parameters of overhead travelling cranes, formulating appropriate conclusions