Dielektrik Malzemelerin Yüzeyleri için Islanabilirlik ve Buharlaşma Hızının Analizine Yönelik Ayrık Kosinüs Dönüşümü Tabanlı Bir Yaklaşım

Year 2021, Volume: 7 Issue: 2, 160 - 168, 30.08.2021

Mustafa Karhan

Abstract

Dielektrik malzemelerin yaşlanması, servis verdikleri süre boyunca kaçınılmaz bir durumdur. Dielektrik malzemelerin, elektriksel özelliklerinin yanısıra yüzey özellikleri de kararlı çalışmasına, performansına ve servis verme süresine etki eden önemli faktörler arasındadır. Elektrik alan ve nem varlığında elektriksel yaşlanma olaylarının başladığı ve hızlandığı ele alındığında, ıslanabilirliğin özellikle outdoor uygulamalarda büyük önem arz eden yüzey özellikleri arasında olduğu aşikardır. Islanabilirlik, katın yüzeylerin karakterize edilmesine ve katı-sıvı etkileşimlerini belirlemeye imkan sağlamaktadır. Bu çalışmada dielektrik malzeme yüzeyine damlatılan 167,9 mS/cm iletkenliğe ve 20 µL hacme sahip tuzlu su damlacıklarının anlık görüntüleri dijital mikroskop kullanılarak 1., 10., 20., 30, 40. ve 50. dakikalar olmak üzere 5 farklı zaman noktası için alınmıştır. Elde edilen görüntüler, görüntü işleme teknikleri kullanılarak iyileştirilmiş ve damlacık görüntüsü bölütlenmiştir. Tuzlu su damlacık görüntülerine Ayrık Kosinüs Dönüşümü (AKD) uygulanmış ve AKD katsayıları çıkartılmıştır. Çıkartılan katsayıların standart sapması zamana bağlı olarak saçılım grafiği çizdirilmiş. Elde edilen zamana bağlı noktalar için eğriler (linear ve quadratic) uydurulmuş ve uydurulan eğrilerin matematiksel eşitlikleri elde edilmiştir. Dielektrik malzemelerinin yüzeyleri için ıslanabilirliği ve buharlaşma hızını değerlendirmeye ve yorumlamaya yönelik olarak AKD tabanlı bir yaklaşım sunulmuştur. Sonuç olarak görüntü işleme teknikleri kullanılarak buharlaşma, zaman, ıslanabilirlik ve temas açısı arasındaki ilişki gözlemlenmiştir.

Keywords

Ayrık Kosinüs Dönüşümü (AKD), dielektrik malzeme, ıslanabilirlik, buharlaşma hızı, görüntü işleme, yaşlanma

A Discrete Cosine Transform Based Approach to Analysis of Evaporation Rate and Wettability for Dielectric Materials' Surfaces

Abstract

The aging of dielectric materials is unavoidable during their service life. In addition to the electrical properties of dielectric materials, the surface properties that affect their stable operation, performance, and service life are among the important factors. Considering that the electrical aging phenomena initiate and grown in the presence of electric field and humidity, it is obvious that wettability is among the surface properties that are of great importance especially in outdoor applications. Wettability allows to characterize of the solid surfaces and determine solid-liquid interactions. In this study, snapshots of saltwater droplets with a conductivity of 167.9 mS/cm and a volume of 20 µL dropped onto the dielectric material surface were taken using a digital microscope for 5 different time points, 1st, 10th, 20th, 30th, 40th, and 50th minutes. The obtained images were enhanced using image processing techniques and the droplet image was segmented. Discrete Cosine Transform (DCT) was applied to the saline droplet images and the DCT coefficients were extracted. The standard deviation of the extracted coefficients was plotted as a time-dependent scatter graph. For the time-dependent points obtained, linear and quadratic polynomial curves were fitted and the mathematical equations of the fitted curves were obtained. A DCT-based approach is presented to evaluate and interpret the wettability and evaporation rate for the dielectric materials' surfaces. As a result, the relationship between evaporation rate, time, wettability, and contact angle is observed using image processing techniques.

Keywords

Discrete Cosine Transform (DCT), dielectric material, wettability, image processing, aging, evaporation rate

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