No-till practices play an important role in decreasing production costs, increasing soil organic matter content, improving soil structure and removing unwanted environmental impacts. However, due to a lack of access to proper machinery for direct seeding in unplowed lands, such practices have failed to produce successful results since they are incapable of providing sufficient contact between soil and seeds. Introducing a machine that can plant seeds and fertilizer at two different depths in hard (unplowed) soils covered with last season’s crop residues can be the first step towards pilot no-till initiatives. This step can finally lead to the promotion of this practice in the potential areas. In this study, different components of a disk furrow opener were optimally designed in Solid Works modelling software. ANSYS was used to analyze this furrow opener and its three main related components. Finally, the coulter’s stress was determined using the von Mises criterion. The result showed that the minimum coulter stress was 1985.5Pa throughout the plane and its maximum belonged to the holes inside the hub with 1.0819x107Pa. The safety factor of the initial coulter was 17.85, while that of the optimally designed coulter was 25. پرونده مقاله

In this paper, dynamic behavior of a functionally graded cantilever micro-beam and its pull-in instability, subjected to simultaneous effects of a thermal moment and nonlinear electrostatic pressure, has been studied. It has been assumed that the top surface is made of pure metal and the bottom surface from a metal–ceramic mixture. The ceramic constituent percent of the bottom surface ranges from 0% to 100%. Along with the Volume Fractional Rule of material, an exponential function has been applied to represent the continuous gradation of the material properties through the micro-beam thickness. Attentions being paid to the ceramic constituent percent of the bottom surface, five different types of FGM micro-beams have been studied. Nonlinear integro-differential thermo-electro-mechanical equation based on Euler–Bernoulli beam theory has been derived. The governing equation in the static case has been solved using Step-by-Step Linearization Method and Finite Difference Method. Fixed points or equilibrium positions and singular points of the FGM micro-beam have been determined and shown in the state control space. In order to study stability of the fixed points, beam motion trajectories have been drawn, with different initial conditions, in the phase plane. In order to find the response of the micro-beam to a step DC voltage, the nonlinear equation of motion has been solved using Galerkin-based reduced-order model and time histories and phase portrait for different applied voltages and various primal temperatures have been illustrated. The effects of temperature change and electrostatic pressure on the deflection and stability of FGM micro-beams having various amounts of the ceramic constituent have been studied . پرونده مقاله

یکی از پارامترهای مهم در عملیات نورد گرم، اندازه‌گیری دمای شمش خروجی از کوره است. براین اساس طراحی یک سیستم الکترونیکی هوشمند خودکار، همانند سیستم بینایی ماشین برای اندازه‌گیری دمای شمش به صورت زمان واقعی ضرورت می‌یابد. در تحقیق حاضر سیستم بینایی ماشین پیشنهادی برای تهیه تصاویر مناسب از شمش داخل کوره، پردازش تصویر بر پایه تفکیک حدود آستانه در فضای رنگی HSI و استخراج خصوصیات آن (اندازه‌گیری دمای شمش)، طراحی شد. برای بررسی تغییر در شرایط نورپردازی، با استفاده از الگوریتم ژنتیک، حدود آستانه سه محدوده دمایی (محدوده دمایی 1 معادل با 1500-1200، محدوده دمایی 2 معادل با1200-900، محدوده دمایی 3 معادل با900-600 درجه سانتیگراد) در تصاویر موزاییکی شمش گداخته، تعیین و مورد تحلیل قرار گرفت. تحلیل عملکرد الگوریتم ژنتیک در فضای رنگی HSI آشکار ساخت که در شرایط متغیر، تفکیک تصویر رنگی براساس این الگوریتم عملکرد معادلی با تحلیل خوشه بندی در تصاویر دارد. بنابراین با این روش می‌توان به تأثیرات شرایط نورپردازی متغیر با پذیرش یک محدوده خطا غلبه کرد. پرونده مقاله