The effect of clutch control parameters on the performance of tractor hydraulic systems was investigated in this study to improve the launch quality of the power shuttle tractor under launch conditions. A power shuttle tractor model for launch control was designed as an integrated mechanical, hydraulic, and electric system; a mathematical model was designed for each subsystem, and nonlinear elements were modeled based on the test data. The designed model was validated by comparing the results of the tractor field test with the simulation results. Launch quality was evaluated based on response time and mean jerk. The larger the clutch pressure gradient in the torque phase, the larger is the mean jerk of the tractor. Further, an appropriate fill pulse pressure is desired because excessive fill pulse pressure can cause overfilling and adversely affect launch quality. A smooth launch is required to improve launch quality; however, if the clutch pressure is small, the launch completion time becomes longer, which deteriorates the launch response, and necessitates a compromise.
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Alopecia areata (AA) is an inflammatory hair loss of unknown etiology.AA is chronic and relapsing, and no effective cure or preventive treatment has been established.Vitamin D was recently reported to be important in cutaneous immune modulation as well as calcium regulation and bone metabolism.It is well known that areata is common clinical finding in patients with vitamin D deficiency, vitamin D-resistant rickets, or vitamin D receptor (VDR) mutation.The biological actions of vitamin D3 derivatives include regulation of epidermal cell proliferation and differentiation and modulation of cytokine production.These effects might explain the efficacy of vitamin D3 derivatives for treating AA.In this study, we report a 7-year-old boy with reduced VDR expression in AA, recovery of whom was observed by topical application of calcipotriol, a strong vitamin D analog.(
Wrinkle formation usually accompanies skin aging. Periorbital wrinkles in particular are an early sign of skin aging. Therefore, several modalities have been developed to treat periorbital wrinkles, including topical applications, surgical techniques, and laser resurfacing. The 2,790-nm yttrium scandium gallium garnet (YSGG) laser has been increasing in popularity recently, but there have been no investigations into the use of a 2,790-nm YSGG laser for the treatment of periorbital wrinkles.To evaluate the clinical efficacy of a 2,790-nm YSGG laser for treating periorbital wrinkles.Ten Korean patients (Fitzpatrick skin type II-V) with periorbital wrinkles were enrolled in this study. They were treated two times with a 4-week interval using a 2,790-nm YSGG laser. The treatment parameters were an average 2-J/cm² fluence, 6-mm spot size, and 0.3-ms pulse width. Treatment consisted of two to three passes of the laser with 20% overlap until a clinical end point of mild erythema was observed. Patients were examined 1 week after each treatment and 3 months after the last treatment. Two independent, blinded dermatologists evaluated clinical improvement using the Fitzpatrick Wrinkle Classification System (FWCS) by comparing digital photographs taken before treatment (baseline) and 3 months after the last treatment. Efficacy was assessed by subtracting the baseline score from the score at 3 months after the last treatment (wrinkle improvement < 0; no change = 0; worsening > 0). At each visit, the patients were also evaluated for any side effects. At the end of the study, the patients documented their degree of satisfaction on a scale of very satisfied, satisfied, slightly satisfied, and unsatisfied.All patients completed the two treatment sessions, and all experienced clinical improvement of periorbital wrinkles based on the physician assessments. The mean treatment efficacies for the right and left sides using the FWCS were -1.85 ± 0.82 and -1.70 ± 0.71, respectively. Nine of 10 participants were satisfied with the procedure. Transient hyperpigmentation and slight exfoliation were observed in one patient after the last treatment, but this disappeared within 10 weeks.In treating periorbital wrinkles, a 2,790-nm YSGG laser treatment might be an effective treatment modality with minimal complications. The authors have indicated no significant interest with commercial supporters.
This study was conducted to develop a load-sensitive engine speed control system to maximize the fuel efficiency of an agricultural tractor. The engine speed controller was developed through a model-based design approach using a tractor simulation model. The simulated engine speed and torque values were measured with an average error range of 1.4–4.9% compared to results obtained from field experiments. Using the tractor model, the gain parameters of the proportional–integral (PI) controller were optimized under the step, ramp, and actual load conditions. The simulation results using the actual load showed that the engine speed could be adjusted to within 2–3% of the desired value using the proposed engine speed controller. The throttle control system was constructed using four parts of a tractor engine, a microprocessor with an engine speed control algorithm, a throttle actuator, and a data acquisition system. Using the developed system, the operating engine speed values showed an average 1.17 % error compared to the desired engine speed. Three fuel efficiency parameters were used for evaluating the fuel-saving performance of the control system: specific volumetric fuel consumption (SVFC), fuel consumption per tilled area (FCA), and fuel consumption per work hour (FC). The values for SVFC, FCA, and FC obtained from the engine speed control system during plowing operations were 23.03–57.87%, 4.11–42.06%, and −7.24–38.48%, respectively, showing an improvement over the same operations without the control system.
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