Calculation of Alumina Hydrosol Concentrations by Using Tyndall Light Dispersion Effect in Colloids

This study is about colloidal mixtures and a method to measure their concentrations. A light beam scatters as it passes through a colloidal mixture. This is called Tyndall Effect. By comparing the effectiveness of Tyndall Effect at different concentration colloids, a formula may be built which can be used to find out the concentration. Research question of this study is this: “Can concentration of an alumina hydrosol be calculated by using scattering ratios of laser beams in hydrosols and does the wavelength of the laser beam affect the accuracy of the concentration calculation?” The reason that this subject is studied for a Chemistry extended essay is that this subject is directly related with environmental chemistry. In lakes, seas, rivers and oceans, colloidal systems can be found. If there is too much alumina particle in a water ecosystem, life in that water may be harmed. The formula that is found in this investigation can be used to easily determine the concentration of particles in water. Different concentrations of Alumina colloids, varying between 20 and 100 μM are tried in this experiment. A strong green light beam is pointed through colloids and their photographs are taken from above the mixtures. The width of light is found in pixels from analysis of photographs and these data are used to determine the relationship between colloid concentration and scattering ratio of the mixture on green laser beam. The same procedure i

Yüzeye entegre membranlı nanomekanik ve mikrodalga eşdüzlemsel dalga kılavuzu temelli biyoalgılayıcılar

Cataloged from PDF version of article.Thesis (M.S.): Bilkent University, Department of Mechanical, İhsan Doğramacı Bilkent University, 2018.Includes bibliographical references (leaves 53-55).Nanoelectromechanical Systems, or NEMS, is the further miniaturized extension of novel devices of 40 years ago, Microelectromechanical Systems or MEMS in short. Nano scale devices first appeared at the dawn of 21st century and they are well established and elaborated by this time to a point which it shapes the technological paradigm of the current decade with various applications such as gene sequencing, improved computers and single molecule detection. The rapid improvement of miniaturization tecniques owes a great deal to the hard work of scientists and engineers of previous generation. Fabrication methods which were limited to a small number which disallowed sub-micron features are improved and new methods have been discovered within the previous decades. This has paved the way for creation of very sensitive sensors in NEMS domain. In this study, a novel biosensor is designed and attempted to be created out of coplanar waveguide resonators which is constructed on top of a nanometers thick membrane and at the sensory region of the resonator a nanopore is proposed to be created. The nanopore is suggested in order to allow nano-particle carrier fluids to pass through the most sensitive region of the resonator, causing a change in its resonant frequency due to electrical property of the nano-particle. The frequency shift caused by particles is suggested to be used to detect and characterize the particles. The particles in this case are planned to be exosomes which are sub-micron packages with cytoplasmic content, naturally secreted by cells for various reasons. Contents of the exosomes may carry diagnostic information about the cell. Exosomes themselves are still being investigated for their uses and benefits within the context of microbiology which makes the proposed device very crucial for ongoing exosome research effort which is still on the rise.by Levent Aslanbaş.M.S

Cumhuriyet Dönemi’nde metroloji ve Ulusal Metroloji Enstitüsü

Ankara : İhsan Doğramacı Bilkent Üniversitesi İktisadi, İdari ve Sosyal Bilimler Fakültesi, Tarih Bölümü, 2014.This work is a student project of the The Department of History, Faculty of Economics, Administrative and Social Sciences, İhsan Doğramacı Bilkent University.by Öztürk, İbrahim Mert