In this paper, the obstacles to solve three-dimensional motion problems using two-dimensional Newton-Euler analyses are presented and examined. The three-dimensional motion analysis method used in industry and medicine is based on a robotic approach and is based on the mathematics of matrix analysis. This approach requires a deep understanding of matrix mathematics and controlling the accuracy of its performance at each stage, which has its own complexities. The aim of this paper is to apply two-dimensional methods for analyzing problems that are inherently three-dimensional and require spatial geometric vector analyses. The main method proposed in this paper to solve the major problem of three-dimensional analyses is to use a two-dimensional image of the member length instead of using the full length of the member in calculations, especially when calculating the moment of inertia of three-dimensional objects on a plane. This research is a type of mathematical analysis and proves the similarity of the results between two-dimensional and three-dimensional approaches in the analysis of three-dimensional problems. The analysis tool in this study is the inverse dynamics method. The assumption of dynamic determinism governs the analysis, that is, for each unknown variable, an equation between the variables in the problem is necessary. This is important in most problems assuming that the spatiotemporal data of the movement of each member and at least one end or joint in the mechanism are known. The results obtained in this paper show that it is possible to calculate the moment of inertia of three-dimensional objects moving in space using two-dimensional kinematic analyses. The advantages and disadvantages of both three-dimensional and two-dimensional methods are mentioned in this research. The use of two-dimensional methods in the analysis of three-dimensional objects moving in space provides a better understanding of the movement and monitoring the results. Also, with this approach, researchers can monitor the accuracy of the results and the spatiotemporal trend of kinematic variables and prevent and avoid computational errors and mathematical modeling in describing three-dimensional movements.

Background and Aims The use of arch support foot orthoses is becoming quite widesprea in the management of foot pathologies. This study examined how lower limb joint angular velocities change with wearing arch support foot orthoses. Methods In this semi-experimental study, 20 healthy male volunteers (age: 34. 2±, 8. 9 years,height: 173. 5±, 5. 4 cm,mass: 76. 3±, 13. 5 kg,and BMI: 25. 7±, 9. 1 kg/m2) participated. The participants completed ten walking trials at a self-selected walking speed while 3-dimensional kinematic data of their ankle, knee, and hip joints were collected. Paired samples t-test was used for comparing two conditions: shod with no orthoses and shod with arch support foot orthoses. Results The use of arch support foot orthoses decreased joint angular velocity for the hip extension (P=0. 000) and ankle dorsiflexion (P=0. 02) compared to walking without orthoses. However, results revealed no significant differences in knee joint angular velocity values between both walking conditions (P=0. 16). Conclusion We concluded that arch support foot orthoses can decrease ankle and hip joint angular velocities. The use of arch-support foot orthoses reduces the risk of overuse injuries by decreasing lower limb joint angular velocities.

Inertial navigation is a method to determine the position, velocity and attitude of a vehicle. In these systems, three perpendicular accelerometers and three perpendicular gyroscopes are used to measure linear accelerations and angular velocities of vehicles, respectively. Using some special equations and the measured accelerations and angular velocities, the position, velocity and attitude of a vehicle can be determined. Although these systems have great advantages, some disadvantages such as the increase of error position, velocity and attitude of vehicle by the passage of time exist. These disadvantages are due to errors of inertial sensors. In this paper, firstly, a suitable error model of inertial sensors is proposed. In the following, to decrease these errors and to correct the operation of inertial navigation system; the INS is integrated with GPS. Integration of INS and GPS is done using extended Kalman filter. To this purpose, required equations and relations for integration of INS and GPS are extracted and proposed completely and illustratively. Finally, the simulation of integration of INS and GPS is presented for two different motion scenarios. The results of simulation show great improvements in characteristic of INS+GPS system in comparison to INS individually.

The transient motion and heat transfer of a viscous incompressible fluid contained between two concentric spheres, maintained at deferent temperatures and rotating about a common axis with deferent angular velocities, is considered numerically, when the angular velocities are arbitrary functions of time. The resulting flow pattern, temperature distribution and heat transfer characteristics are presented for the various cases, including exponential and sinusoidal angular velocities. An interesting eject, of long delays in the heat transfer of a large portion of the fluid in the annulus, is observed, because of the angular velocities of the corresponding spheres.

The similarity solution of the steady-state motion and heat transfer of a viscous incompressible fluid contained between two concentric spheres, maintained at different temperatures and rotating about a common axis with different constant angular velocities is considered. The resulting flow pattern, temperature distribution and heat transfer characteristics are presented for various cases. Aside from the energy equation, the same results as previous works are obtained for Navier-Stokes equations, but with less computational complexities.

Background and Aim: angular cheilitis is a common condition among dental patients. However, it often responds poorly to antifungal treatment, and the use of corticosteroids can lead to lesion recurrence or medication resistance. This study aimed to assess the frequency of Staphylococcus aureus in patients who visited the Oral and Maxillofacial Medicine Department at Yazd Dental Faculty in 2017. Methods: This case- control study included 163 participants, with 65 patients diagnosed with angular cheilitis in the case group and 98 healthy individuals in the control group. Swabs were collected and inoculated on blood agar and Sabouraud dextrose agar. The cultures were then examined for the presence of Staphylococcus aureus and Candida albicans. Data were analyzed using SPSS software, employing Chi- square and t-tests, with a significance level set at  p < 0.05. Results: The study included 98 healthy individuals and 65 patients with angular cheilitis. The results indicated that Staphylococcus aureus was not detected in either the patient or control group (p < 0.9). A higher prevalence of angular cheilitis was observed among female patients. Additionally, there was a direct correlation between the presence of angular cheilitis and Candida albicans. Conclusion: The findings suggest that Staphylococcus aureus is not a contributing factor in angular cheilitis lesions. Therefore, antibiotic treatment for refractory cases should be postponed until microbial cultures confirm bacterial involvement.

The transient motion and the heat transfer of a viscous incompressible flow contained between two vertically eccentric spheres maintained at different temperatures and rotating about a common axis with different angular velocities is numerically considered when the angular velocities are an arbitrary functions of time. The resulting flow pattern, temperature distribution, and heat transfer characteristics are presented for the various cases including exponential and sinusoidal angular velocities. Interesting effect of long delays in heat transfer of large portions of the fluid in the annulus is observed because of the angular velocities of the corresponding spheres. As the eccentricity increases and the gap between the spheres decreases, the coriolis forces and convection heat transfer effect in the narrower portion increase.

In this paper, a new control method based on the linear matrix inequality is used to control the speed of a hybrid stepper motor. The proposed method is proved based on the Lyapunov criterion. The proposed method has a higher degree of freedom than conventional robust controllers, which can be used to better control the system. The proposed method also exhibits high robustness against the uncertainty of the hybrid stepper motor parameters as well as the applied disturbances. Also in this method, the effect of rapid changes in the reference speed of the hybrid stepper motor are considered so that the controller can have more effective tracking. The proposed control method is compared with the Self-tuning PI controller and PI (Ziegler-Nichols) controller in multiple scenarios considering the uncertainty of the parameters and different disturbances. The obtained results indicate that the proposed controller has a better performance against the disturbances and uncertainty of the parameters in comparison with the abovementioned controllers. It should be noted that the simulations have been performed in Matlab.