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This paper proposes a new design for line-start operation of synchronous reluctance motors. In the past years, synchronous reluctance motors have been studied by many researchers. Due to high efficiency, they have gained increasing interest because in the synchronous operation, there is limited losses in the rotor. On the other hand, line-start operation of the synchronous reluctance motors is an important challenge that can make this type of the motors popular in many applications. However, line-start operation techniques should not considerably affect the steady-state characteristics of the motor. In the proposed design, the arrangement, size and shape of the rotor conductor bars are designed based on the rotor magnetic circuit difference between induction and reluctance synchronous motors. Complete assessment of the motor parameters are examined using finite element analysis. The proposed structure improves the starting characteristics of the motor. Moreover, power factor of the proposed motor is slightly increased in comparison to that of conventional line-start synchronous reluctance motors. The results obviously show effectiveness of the proposed line-start operation strategy for the synchronous reluctance motors. Finally, experimental verification are also included to confirm the finite element analysis results. [ABSTRACT FROM AUTHOR]

Background: Today, contact lenses have extensive usages. Contact lens places on cornea, so it may induce variation on cornea and these variations can influence the measurement of intraocular pressure (IOP) by Goldman tonometer. The aim of this research was to study the effect of various contact lenses on measurement of intraocular pressure by Goldman tonometer. Materials and Methods: In this study, 80 subjects aged 18-25 were selected randomly among patients of Al-Zahra ophthalmology center. None of them has any eye pathological problems. Before wearing the lens, intraocular pressure was measured, and then patients were divided into two groups of soft and hard contact lenses. Soft and hard contact lenses were placed on the eye for two hours, and the intraocular pressure was measured again. Results: The mean of IOP before wearing contact lenses and two hours later was 15.96 mmHg and 13.93, s respectively. Paired test showed a significant difference between IOP before and after wearing contact lenses (p=0.001).There was no significant differences in mean of intraocular pressure decline before and after placing the contact lens in both soft and hard lenses. Conclusion: According to this study, the intraocular pressure decreases after wearing contact lenses (CL). This decline may be due to variation in properties of cornea after wearing CL that can also affect IOP measurement. [ABSTRACT FROM AUTHOR]

Purpose: To compare the effectiveness of pencil push-up therapy (PPT) versus office-based vision therapy in patients with convergence insufficiency. Materials and Methods: In this study, 60 students from Zahedan University of Medical Sciences with convergence insufficiency were selected. After determining their refractive error (with a retinoscope), near point of convergence (by millimeter ruler), near heterophoria (by alternate prism cover test), and positive fusional vergence at near (by prism bar), subjects were divided into two groups to receive PPT (at least three times a day for 5 minutes each time) or office-based therapy (two times each week for 60 minutes each visit) without home reinforcement. Subjects were re-examined 4 and 8 weeks after initiation of treatment. Statistical analysis was performed with the independent samples t-test and the analysis of variance (ANOVA). Statistical significance was indicated by P < 0.05. Results: The near point of convergence, phoria, and positive fusional vergence were not statistically different between the two groups before treatment (P > 0.05). After 4 and 8 weeks of therapy, only the positive fusional vergence was statistically significantly different between groups (P = 0.001). Results from ANOVA indicated a considerable difference between the two groups in general but the observed difference was related only to positive fusional vergence. Conclusion: PPT and office-based vision therapy are comparable for treatment of convergence insufficiency. While we do not deny the more efficacious nature of office-based therapy, it is not always practical, may be too expensive, and may not be locally available. A home-based therapy offers a cost-effective reasonable alternative. [ABSTRACT FROM AUTHOR]

Aims/Purpose: To determine the association between dry eye with higher order aberrations (HOAs) and contrast sensitivity in 60 years old people and over. Methods: This population‐based study was conducted in Tehran, the capital of Iran, using stratified multistage random cluster sampling. All participants underwent complete ocular examination including measurement of uncorrected and best‐corrected visual acuity, refraction, slit‐lamp biomicroscopy. Zywave was used for measuring HOAs aberrations. Contrast sensitivity was measured with best correction visual acuity using the CVS1000 grating charts. Schirmer and tear break‐up time (TBUT) tests were used for evaluating dry eye in participants. Results: After applying exclusion criteria, the data of 397 individuals were analysed. A total of 415 people were invited, of whom 397 (62.8%) were females. The mean age of the participants was 68.32 ± 5.49 years. After adjusting with age and sex, in the multiple regression model that the TBUT test has a direct association with spherical aberration (p = 0.017) and an inverse association with coma, trefoil and the third, fourth and fifth order aberrations (p < 0.05). Schirmer test results also had a positive relationship with spherical aberration (p = 0.046) and an inverse relationship with coma, trefoil and the third, fourth and fifth order aberrations (p < 0.05). Contrast sensitivity had a significant association with Schirmer test result only in spatial frequency of 3CPD. Conclusions: The results of this study indicated the association between dry eyes and HOAs, and that the TBUT and Schirmer test results are of the most important factors in this relationship. Treating dry eye, can improve HOAs and quality of vision in elderly people. [ABSTRACT FROM AUTHOR]