Numerical simulation of single stage gearbox with tooth damage

This article deals with numerical simulation of single stage gearbox dynamic behavior. At first, the whole methodology is verified by an experimental approach. To assess the effect of gear damage there are four variants calculated, the first variant is without damage and the other three variants are with incorporated damage in different position. The surface normal velocity on the gearbox housing is computed and compared among the individual variants as the most evaluating factor. Finally, this study proves that the numerical simulation is a useful tool at the development phase, as well as, at the testing phase to confirm if the dominant problem is caused by the tooth quality

The effect of the gear parameters to the noise of transmission

This paper deals with the investigation of the particular gearbox parameters’ effect on the noise of transmission. First, a single stage gearbox is designed and manufactured in order to validate input and results of the whole methodology. Second, the dynamic model is built for the single stage gearbox and each step is validated by an experiment. After well corresponding to the measurement, an additional simulation is performed to verify the influence. The impact of torque amount, imbalance position, backlash size, and torsion stiffness of each part is mainly investigated. The used method is able to determine the impact of each modification, thus it can be useful at the design phase and also during measurement or investigation of a real problem

Modelling the powertrain rubber coupling under dynamic conditions

This paper presents a strategy for computational modelling of elastic rubber couplings under dynamic loading. Methods how to determine static and dynamic characteristics of the elastic coupling based on static and dynamic experimental tests of rubber elements are presented. The nonlinear deformation behaviour, frequency and temperature dependent properties of rubber are considered for computational models. The model is applied to the elastic coupling connecting an in-line six-cylinder natural gas engine and an electrical generator. Loading forces are based on in-cylinder pressure measurement. Experimental verification of the computational model results is carried out by measuring the values on a test engine using the non-contact laser measuring technique

Numerical simulation of gearbox structure dynamics focused on backlash influence

This paper deals with numerical investigation of the single–stage gearbox housing dynamic behaviour during low-torque operating conditions. First the modal properties of the key components are derived and experimentally evaluated on the physical model. Next the main simulations are performed in MBS (multi-body system) software, the model is based on the open loop test rig. The computational methods aim to represent dynamic behaviour of the gearbox housing key parts with respect to NVH parameters evaluation, which is done by surface normal velocity amplitude. The presented part of investigation also deals with different kind of input speed variability. The simulation results show that the variable input speed has strong influence on dynamic behaviour

Encapsulation system for the immunoisolation of living cells

The present invention is drawn to a composition of matter comprising high viscosity sodium alginate, cellulose sulfate and a multi-component polycation. Additionally, the present invention provides methods for making capsules, measuring capsule permeability to immunologically-relevant proteins and treating disease in an animal using encapsulated cells. Over one thousand combinations of polyanions and polycations were examined as polymer candidates suitable for encapsulation of living cells and thirty-three pairs were effective. The combination of sodium alginate, cellulose sulfate, poly(methylene-co-guanidine) hydrochloride, calcium chloride, and sodium chloride produced the most desirable results. Pancreatic islets encapsulated in this multicomponent capsule demonstrated glucose-stimulated insulin secretion in vitro and reversed diabetes without stimulating immune reaction in mice. The capsule formulation and system of the present invention allows independent adjustments of capsule size, wall thickness, mechanical strength and permeability, and offers distinct advantages for immunoisolating cells

Recombinant DNA technology II/ Edit.: Rakesh K. Bajpai

xii, p. 495.: ill.; 23 c

The Effect of pH and Air Superficial Velocity on the Foam Fractionation of Okra (<i>Hibiscus esculentus</i>)

513-520separation technique that utilizes the differences in surface activities of molecules in a bulk solution. Fresh frozen cut okra, a product of EI Salvador, Guatemala, or Mexico, was obtained from a local grocery store. Surface tension analysis indicated that a pH value of 7 yielded the best separation due to the increased surface-activity of the proteins in solution (minimization of surface tension). The optimum concentration to be used in foam fractionation for the initial bulk solution has also been determined via surface tension analysis. Laboratory experiments show that a 14-weight per cent solution (a 7-fold dilution has been used to pre-remove the cellulose by vacuum filtration) maximize the separation ratio during the foam fractionation experiments. The superficial air velocity, Vo, maximized the separation ratio of 110 cm/min in the range 70 ≤ V<span style="font-size:12.0pt; font-family:" times="" new="" roman";mso-fareast-font-family:fd1634814-identity-h;="" mso-bidi-font-style:italic"="">o ≤ 150 sec/min. The effect of pH on the separation ratio has been examined for two okra samples. The results show that sample 1 hardly foamed over the entire pH range while sample 2 completely foamed over the same range. It is speculated that the presence of anti-foaming agents in the okra determines the extent of foaming and their presence could possibly be related to the location in which the sample is harvested. Actual harvest locations were not given on the okra package. The mean viscosity of the okra solution has been determined to be about 67% greater than that of water. The addition of an emulsifying agent (carboxymethyl cellulose, CMC) to the okra solution has been found to first enhance and then suppress the total foamate volume as the concentration of the CMC is increased