فهرس المقالات Surface energy

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  1 - Modification of surface energy and electrical and thermal properties of spherical polypyrrole nanoparticles synthesized by CTAB for potential application as a conductive ink
  Kasra Vahidi Yousef Seyed Jalili
  10.1186/2251-7235-7-42
  AbstractPolypyrrole (PPy) fine powder was synthesized via a chemical route in the presence of various concentrations of the cationic surfactant cetyltrimethylammonium bromide. The effect of the concentration of the surfactant used on electronic, structural, thermal, and أکثر

  AbstractPolypyrrole (PPy) fine powder was synthesized via a chemical route in the presence of various concentrations of the cationic surfactant cetyltrimethylammonium bromide. The effect of the concentration of the surfactant used on electronic, structural, thermal, and surface properties of the final product was investigated. The sample prepared with the highest concentration of surfactant yielded mostly the best electronic, thermal, and physical characteristic properties, a lot closer to the materials used in conductive inks. The electrical conductivity of the sample underwent an increase of 320%. Fourier transform infrared spectroscopy indicated that all surfactant has been excluded at the final stage of the synthesis, and the results indicated higher doping levels for higher concentrations of surfactant used. Surface energy showed a dramatic increase, and spherical nanoparticles were seen in scanning electron microscopy images. The PPy powder became soluble in polar solvents, becoming highly hydrophilic and indicating good mass retention upon thermal degradation. تفاصيل المقالة
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  2 - An Analytical Study on Surface Energy Effect on Free Longitudinal Vibration of Cracked Nanorods
  H Shokrollahi R Nazemnezhad
  10.22034/jsm.2023.1987288.1778
  The present work analytically studies the free longitudinal vibration of nanorods in the presence of cracks based on the surface elasticity theory. To this end, governing equations of motion and corresponding boundary conditions are obtained using Hamilton’s princ أکثر

  The present work analytically studies the free longitudinal vibration of nanorods in the presence of cracks based on the surface elasticity theory. To this end, governing equations of motion and corresponding boundary conditions are obtained using Hamilton’s principle. Due to considering the surface stress effect, as well as the surface density and the surface Lamé constants, the obtained governing equations of motion become non-homogeneous. The non-homogeneous governing equations are solved using appropriate analytical methods, and the natural frequencies are extracted. To have a comprehensive research, the effects of various parameters such as the length and radius of the nanorod, the crack severity, the crack position, the type of boundary condition, and the values of surface and bulk material properties on axial frequencies of the nanorod are investigated. Since this work considers the effects of all surface energy parameters, it can be claimed that it is a comprehensive study in this regard. تفاصيل المقالة
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  3 - Effect of Surface Energy on the Vibration Analysis of Rotating Nanobeam
  M Safarabadi M Mohammadi A Farajpour M Goodarzi
  In this study, the free vibration behavior of rotating nanobeam is studied. Surface effects on the vibration frequencies of nanobeam are considered. To incorporate surface effects, Gurtin–Murdoch model is proposed to satisfy the surface balance equations of the co أکثر

  In this study, the free vibration behavior of rotating nanobeam is studied. Surface effects on the vibration frequencies of nanobeam are considered. To incorporate surface effects, Gurtin–Murdoch model is proposed to satisfy the surface balance equations of the continuum surface elasticity. Differential quadrature method is employed and in order to establish the accuracy and applicability of the proposed model, the numerical results are presented to be compared with those available in the literature. The effects of angular velocity, boundary conditions and surface elastic constants on the vibration characteristics are presented. Numerical results show that the softer boundary conditions cause an increase in the influence of the angular velocity on the nanobeam vibration frequencies. تفاصيل المقالة
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  4 - تحلیل ارتعاشات و کنترل میکروتیر یکسر گیردار به همراه لایه های عملگر و حسگر پیزوالکتریک با فرض اثرات سطح
  سید علی افتخاری محمد خواجه خباز محمد هاشمیان
  امروزه پیش‌بینی رفتار ارتعاشی و دینامیکی سازه‌های میکرو مورد توجه بسیاری از پژوهشگران قرار گرفته است. در این پژوهش تحلیل ارتعاشات و کنترل میکروتیر یکسر گیردار به همراه لایه‌های پیزوالکتریک عملگر و حسگر با فرض اثرات تنش سطح مورد ارزیابی قرار گرفته است. معادلات دیفرانسیل أکثر

  امروزه پیش‌بینی رفتار ارتعاشی و دینامیکی سازه‌های میکرو مورد توجه بسیاری از پژوهشگران قرار گرفته است. در این پژوهش تحلیل ارتعاشات و کنترل میکروتیر یکسر گیردار به همراه لایه‌های پیزوالکتریک عملگر و حسگر با فرض اثرات تنش سطح مورد ارزیابی قرار گرفته است. معادلات دیفرانسیل حاکم با استفاده از روش انرژی و اصل همیلتون استخراج شده و از روش مجموع مربعات دیفرانسیلی تعمیم یافته برای گسسته-سازی و تبدیل معادلات دیفرانسیل پاره‌ای به دسته معادلات دیفرانسیل معمولی استفاده شده است. اثر تغییرات هندسه مدل و مدول الاستیسیته سطح، تنش پسماند سطح و چگالی سطحی بر فرکانس طبیعی مدل میکروتیر با لایه‌های پیزوالکتریک بررسی شده است. همچنین تأثیر طراحی کنترلر بهینه خطی بر تغییرات پاسخ دینامیکی و ولتاژ کنترلی پیزوالکتریک مورد ارزیابی قرار گرفته است. نتایج نشان دهنده‌ی افزایش سرعت پاسخ و کاهش سریعتر دامنه ارتعاشی مدل با طراحی کنترل بهینه خطی است. تفاصيل المقالة