A Comparison of Circular and Slotted Synthetic Jets for Flow Control in a Twin Air Intake

The performance of an aircraft engine depends on air flow quality at the engine face / the exit of the air-intake also known as aerodynamic inlet plane (AIP). A single-engine aircraft has complex Y-shaped twin air-intake which causes severe flow separation, distortion and flow non-uniformity at the AIP. The present study compares the efficacy of slotted synthetic jet and a row of four circular synthetic jets attached to inner faces of a twin air-intake to improve aerodynamic performance at the AIP. The results are obtained using computational fluid dynamics. The velocity and vorticity plots show that lateral spread of the circular jets is limited as compared to the slotted jet. The circular jets are found to be weak as compared to slotted jet to prevent separation of main flow occurring in the twin air-intake. The various aerodynamic performance parameters, such as static pressure recovery coefficient, total pressure loss coefficient, distortion coefficient and secondary flow uniformity are compared for both the cases, exhibiting marked improvement in all these parameters. The study demonstrates that the slotted synthetic jets is a better option for controlling flow in twin air-intake as compared to a row of circular synthetic jets

Impacts of Transit Priority on Signal Coordination

This study introduces the current application of transit signal priority (TSP) in the City of Toronto, Ontario, Canada, and focuses on the following: traffic signal operations, constraints of the current signal control system and TSP technology, evaluation metrics, and models for simulating transit priority operation. In Toronto, 335 traffic signals have transit priority, 321 of which are under the control of the main traffic signal system (MTSS). Active transit priority unconditionally allows an extension of up to 30 s per cycle in addition to the normal signal green time on transit routes. The extension generates complaints about traffic delays for vehicles on side streets, long pedestrian wait times, and poor signal coordination. Field tests were conducted on a section of a downtown Toronto arterial bus route. Actual MTSS logs and signpost data obtained by the transit agency during field tests were used to investigate three scenarios along Bathurst Street at six signalized intersections. An analysis of signal timing changes that encompassed selection and determination of traffic operation performance measures was conducted on a per-cycle basis in the morning peak, afternoon peak, and off-peak periods. Green-band effectiveness was one of the evaluation measures used to assess signal progression. Subsequently, a performance assessment frame based on a model for the analytic hierarchy process was built to determine the best scenario and to help develop simulation models. The analysis shows that the TSP strategy of unconditional extension up to 30 s in signal green time is not recommended for use with the existing system of traffic signal control. The approaches described can apply to different transit routes with variable situations in Toronto

Scleral buckling-induced ocular parameter changes in different age group patients of rhegmatogenous retinal detachment

Purpose: This study was aimed to evaluate the difference in the ocular parameter changes following scleral buckling (SB) for rhegmatogenous retinal detachment (RRD) in different age group patients. Materials and Methods: This prospective study included 26 eyes of 26 patients who underwent SB for uncomplicated RRD. The patients were divided into three age groups: 16–30 years (Group I), 31–45 years (Group II), and 46–60 years (Group III). Axial length (AL), anterior chamber depth (ACD), and corneal curvatures were measured preoperatively and postoperatively at 1 week, 1 month, and 3-month. The postoperative change and progression of these parameters were evaluated and compared between three age groups using nonparametric Wilcoxon signed-rank test and Kruskal–Wallis test. Results: At 3-month follow-up, a statistically significant postoperative AL increase, ACD decrease, and surgically induced astigmatism (SIA) were observed in all groups (Group I - 0.75 ± 0.32 mm, 0.21 ± 0.21 mm, and 1.5 ± 0.48 D, respectively; Group II - 0.79 ± 0.41 mm, 0.14 ± 0.04 mm, and 2.07 ± 1.18 D, respectively; Group III - 0.86 ± 0.33 mm, 0.16 ± 0.05 mm, and 1.56 ± 1.19 D, respectively). However, surgery-induced change for any parameter was not significantly different between the groups (P for AL [0.7955]; ACD [0.8805]; and SIA [0.5485]). Progression in postoperative changes in AL and ACD was insignificant during three follow-up examinations in all the groups. However, SIA of Group I continued to change significantly up to 3 months but stopped to change at 1 month only in Group II and III. Conclusion: Age-related change in physical properties of ocular tissue does not have any major additional effect on the results of SB except that the postsurgical change in corneal curvature stops earlier in older patients compared to that in younger patients