The SINGLE WHEEL TESTER is an experimental device used to measure WHEEL forces when studying the relation of soil and WHEEL in a soil bin or in the field. In the model under development, a special frame holding the test WHEEL is connected to a loading carriage by two pairs of vertical rails and four rollers to provide a floating connection. By applying a driving torque to the test WHEEL shaft, the TESTER frame and loading carriage moved along the soil bin and the net traction force developed by the test WHEEL is measured using a pair of force transducers (load cells). The driving unit consists of a 3-phase, 1.1 kW AC motor and a reduction gear unit (gear ratio 1:48). The drive unit is mounted on an independent frame which is mounted on the TESTER frame by a pivot shaft running through the center of mass of the drive assembly. A chain drive system transmits the output rotation of the drive unit to the test WHEEL axis. The torque transmitted to the test WHEEL was calculated by measuring the tension force of the chain using a load cell to measure the reaction force sensed by the pivotal frame during transmission. Rotary and linear encoders equipped with infrared sensors were used to measure angular and linear velocities of the test WHEEL and TESTER frame, respectively. The sensor output was sent to a data acquisition board to digitalize the data before being sent to a computer for further processing. The SINGLE WHEEL TESTER was capable of measuring net traction, linear and angular velocities, slippage and driving torque of test WHEELs as large as 25 em in width, 70 em in diameter and with a maximum net traction of 600 N and maximum torque of 170 N-m. During the evaluation tests, the traction parameters of an agricultural tire with an inflation pressure of 140 kPa, intended for a walking tractor, were measured. The evaluation results were recorded in diagrams of net traction force, driving torque, angular velocity; travel speed and WHEEL slip along a 2.5 m test track in a laboratory soil bin.

The tire-mechanics models have been developed for the study of WHEEL movement on the road or soil surface while these models are unlikely to describe the motion of WHEELs on uneven surfaces. Due to dynamical complexity of this phenomena and the importance of this subject for farm conditions and the WHEEL carrier devices, the present research aimed to investigate the effects of several parameters on the WHEEL passing the obstacle. The experiments were carried out using SINGLE WHEEL TESTER in soil bin condition. The results indicated a relatively linear relationship between the impact force applied on tire and forward speed of WHEEL and also the height of rectangular obstacle. The effect of inflation pressure was inversed in the range of complete formed tire’s body on impact force and in low levels of tire inflation pressure; tire’s body damps the maximum impact forces. The medium levels of pressure (about 150-200 kPa) resulted in less horizontal force that applied on the WHEEL for different levels of forward speed and obstacle’s height. Tractive force for passing obstacle was increased by raising forward speed and the obstacle’s height.

In this study, a SINGLE tire TESTER was used to study the effects of vertical load, inflation pressure and moisture content on tire rolling resistance in a soil bin. A Goodyear 12. 4-28, 6 ply tractor drive tire was employed and the soil texture was a clay loam. The experimental design was a completely randomized with factorial layout at three replications. A multivariate regression model was obtained with the correlation coefficient of R2=0. 85 to predict the tire rolling resistance based on vertical load, inflation pressure, and moisture content. A multilayer feed-forward ANN (artificial neural network) with standard BP (back propagation) algorithm and LM (Levenberg-Marquardt) training function by using of two hidden layer in the network architecture was employed. RMSE (root mean squared error) and R2 was used as modeling performance criteria. Tire inflation pressure was identified as the controller parameter of tire rolling resistance at low moisture content and also moisture content was the most effective parameter on changing of rolling resistance in regression model. Also the obtained R2=0. 977 from ANN model showed that ANN data were more close to actual data than the regression model.

In this paper, the vibrations on the sample of a SINGLE-rail sled TESTER system with dampers are investigated. First, by extracting the vibration equations governing the problem coded in MATLAB software and by drawing the FFT diagram, the natural frequencies of the system are obtained. The first and second frequencies of the system are related to torsional displacement and transverse sled displacement, respectively. Due to the structural damping of the sled system, to extract the equivalent stiffness and equivalent damping values, the experimental test is used by the harmonic dynamic test device. Then, by simulating the sled model in ABAQUS software, modal analysis is performed and natural frequencies and mode shapes are extracted. Finally, by constructing a designed sled model and performing experimental modal analysis, the natural frequencies of the system are compared with the previous two methods and confirmed with an error of less than 9%.KeywordsSled TESTER system, natural frequency, modal analysis, equivalent stiffness, equivalent damping.

Local flux may be distorted in many regions of core, although total flux is usually sinusoidal. When attempting to predict the loss distribution in materials operating under localized distorted flux conditions, which occur in machines and transformer cores, it is essential that proper account of the waveform be taken. Moreover for development of new magnetic materials and generation of better magnetic sheets, it is necessary to implement detailed measurement for their property specifications. One of these property specifications is loss under distorted flux conditions. A high precision SINGLE Sheet TESTER (SST) was implemented in which the specification of the sample sheet will be measured by software processing of Band H. The finite element method was used for the magnetic field study. The field distribution was calculated inside and outside the sample, in which way the error was obtained. By different section of the winding in exciting coil the field uniformity was improved and finally the implemented system shows error less than 0.6% in measurement of hysterics loss of magnetic sheets. Loss due to distorted flux was measured for different harmonics and in distinct amplitudes and phases. A range of non-oriented and grain oriented materials were tested under distorted flux waveform condition. For non-oriented sheets loss measured about 10% by applying 15% third harmonic to exciting waveform, while this value was about 25% for many of grain oriented sheets. Moreover, based on implemented measurements, harmonic phase affects on loss and makes about 22% error in loss prediction for non-oriented sheets.

Coefficient of friction (COF) for rubber parts is one of the key parameters in their interaction with solid rough surfaces (micrometer to millimeter scales), such as tire-road interactions. COF of rubber depends on viscoelastic properties of rubber, roughness characteristics of the counter-part surface, and process variables such as contact nominal pressure and sliding speed. Due to the need for measuring COF for rubber, a new friction TESTER, with continuous variation of nominal pressure and sliding speed, was designed and constructed in order to assess the effect of above mentioned parameters. Tire tread compounds, as the most common rubber part in the field of rubber tribology, was used for this purpose. Viscoelastic properties of compounds were varied by changing composition of styrene-butadiene rubber (SBR) and butadiene rubber (BR) in the blend. Effect of surface roughness was evaluated by using silicon-carbide papers with different roughness parameters. By statistical analysis it was shown that the designed friction TESTER has high accuracy in measuring the coefficient of friction of rubber and differentiating the effective parameters.Increasing the nominal pressure led to reduction of COF and increase in sliding speed forced it through a maximum. In conclusion, the loss factor of the compound and asymmetry in roughness distribution of the counter-surface are considered as the most effective parameters on COF of rubber.

One of the important features of an interconnection network is its ability to efficiently simulate programs or parallel algorithms written for other architectures. Such a simulation problem can be mathematically formulated as a graph embedding problem. In this paper we compute the lower bound for dilation and congestion of embedding onto WHEEL-like networks. Further, we compute the exact dilation of embedding WHEELlike networks into hypertrees, proving that the lower bound obtained is sharp. Again, we compute the exact congestion of embedding windmill graphs into circulant graphs, proving that the lower bound obtained is sharp. Further, we compute the exact wirelength of embedding WHEELs and fans into 1, 2-fault hamiltonian graphs. Using this we estimate the exact wirelength of embedding WHEELs and fans into circulant graphs, generalized Petersen graphs, augmented cubes, crossed cubes, Möbius cubes, twisted cubes, twisted n-cubes, locally twisted cubes, generalized twisted cubes, odd-dimensional cube connected cycle, hierarchical cubic networks, alternating group graphs, arrangement graphs, 3-regular planer hamiltonian graphs, star graphs, generalised matching networks, fully connected cubic networks, tori and 1-fault traceable graphs.

Statement of problem: The electric pulp test (EPT) is an important diagnostic aid in evaluation of pulpal vitality. It was postulated that premeditation with analgesics can decrease tooth sensitivity to electric stimulation.Purpose: The purpose of this study was to evaluate the effect of premeditation with ibuprofen on the responses of vital central teeth to electric pulp TESTER.Materials and method: This clinical trial study was performed on 88 intact maxillary central and lateral incisors. After taking medical and dental histories and clinical examinations, electric pulp testing was done using tooth paste as conducting medium and the results were recorded. Afterwards, each subject received a 400mg ibuprofen tablet and one hour later, electric pulp testing was conducted again. The data were statistically analyzed using t-test to compare pre- and post-medication records.Results: The mean EPT scale of teeth before ibuprofen administration was 2.5, whereas after drug administration the mean EPT scale of the teeth was 2.7. Statistical analysis showed significant differences.Conclusion: This investigation showed that, although ibuprofen decreased the tooth sensitivity to electrical stimulation, but with proper attention in using pulp TESTER, it could still be a valuable aid in clinical practice for patient's receiving Ibuprofen.