Browsing by Subject "Thermal"

Now showing 1 - 3 of 3

Restricted
Afyonkarahisar’ın şifalı suları: Gazlıgöl
(Bilkent University, 2022) Tatar, Eda; Köse, Zeynep; Yıldırım, Canan; Uludağ, Ulaş; Bulut, Buğra
Sağlık turizminin alt dallarından biri olarak ortaya çıkan termal su turizmi, belirli bölgelerden çıkarılan ve kaplıca suyu adı verilen suların tedavi edici etkisini temel alır. Kaplıca suyu, içerdiği zengin mineraller sayesinde başta romatizma, böbrek ve idrar yolları hastalıkları, cilt hastalıkları ve metabolizma bozuklukları gibi çeşitli hastalıkların tedavisinde kullanılmaktadır. Termal suların şifasından yararlanırken aynı zamanda tatil ihtiyacını gidermek isteyen birçok turist bu turizm türünü tercih etmektedir. Her bölgeden çıkmayan bu kaplıca suları, fay hatlarının geçtiği yerlerde yoğunluk gösterir. Bu bölgelerden biri olan Afyonkarahisar şehrinde başta Gazlıgöl olmak üzere dört ana kaplıca merkezi bulunmaktadır. Tarihi Frigyalılar dönemine kadar uzanan Gazlıgöl kaplıcası, 1980 yılından sonra açılan devremülk ve oteller sayesinde Afyonkarahisar bölgesi için bir termal merkez konumuna gelmiştir. Ayrıca burada çıkarılan termal suyun içilebilir nitelikte oluşu, Kızılay Maden Sularının çevreye tesis kurmasıyla bölgeyi önemli bir ekonomik gelir kaynağı haline getirmiştir. Termal turizmin bir diğer önemli ekonomik katkısı ise dört mevsim yapılabilen bir turizm türü olması sebebiyle tesislerde kesintisiz bir iş gücüne ihtiyaç duyması ve sonuç olarak halka iş imkanı sağlamasıdır. Bununla birlikte, dört mevsim ziyaret eden turistler yöreye özel sucuk, kaymak, lokum gibi lezzetlerin satışını arttırdığı için yerel esnafa da gelir sağlamaktadır. Son olarak, termal suların ısınmada da kullanılabileceğinin fark edilmesiyle birlikte 1994 yılından itibaren doğalgaza alternatif olmuş ve günümüzde ise Afyonkarahisar bölgesi için temel ısınma kaynağı haline gelmiştir. Termal suların detaylı araştırılması, bu suların sağladığı çeşitli yararların ve ülkemizdeki konumunun öneminin daha detaylı anlaşılmasını sağlayacaktır.
Open Access
Polybenzoxazine based high performance nanofibers via electrospinning
(2016-08) Ertaş, Yelda
Polybenzoxazines are newly developing phenolic type thermoset resins having fascinating properties which overcome the shortcomings of the traditional resins. In recent years, polybenzoxazines are attracting much interest because of their outstanding features, such as near-zero volumetric change upon curing, no by-products during curing, low water absorption, high glass transition temperature and high char yield. In addition, the molecular structure of polybenzoxazines facilitates immense design flexibility which enables tailoring the properties of the cured material for a wide range of application. Electrospinning is a widely used simple and cost-effective technique to produce nanofibers from various polymers, polymer blends, inorganic materials, supramolecular structures and composites. In principle, a continuous filament is formed from polymer solution or melt under high electric field which resulted in fibers with diameters ranging from tens of nanometers to few microns. Nanofibers produced with electrospinning technique show unique physical/chemical properties due to their very high surface area and nanoporous structures. In this thesis, we have produced polybenzoxazine based high performance nanofibrous materials via electrospinning by using two approaches. In the first approach, main-chain polybenzoxazines (MCPBz) were synthesized to produce bead free and uniform nanofibers without using polymeric carrier matrix. However, it was observed that these nanofibers lost the fiber morphology at low temperatures and they formed film before cross-linking. Subsequently, novel photo/thermal curable MCPBz resins were designed and synthesized readily owing to the design flexibility of polybenzoxazines in order to enhance thermal stability of MCPBz nanofibers. Therefore, firstly photo curing was performed to improve the thermal stability of nanofibers and then, thermal curing was carried out at high temperatures to obtain cross-linked MCPBz nanofibers with good thermal and mechanical properties. In addition, it was shown that these cross-linked and highly porous MCPBz nanofibers are very stable in various organic solvents, highly concentrated acid solutions and at high temperatures which make these nanofibers quite useful for the certain filtration applications requiring high temperatures and harsh environmental conditions. In the second approach, we produced polybenzoxazine based composite nanofibers from both polymeric materials and non-polymeric systems (cyclodextrins) with enhanced thermal and mechanical properties. At the same time, PAHs, dye molecules and heavy metal ions removal experiments were performed with polybenzoxazine based composite nanofibers to demonstrate their potential application for the waste water treatment.
Embargo
Suppressing the nonreciprocal errors in a fiber optic rotation sensor
(2024-02) Andaç, Tuğba
Among several other types of rotation sensors, interferometric fiber optic gyro-scopes (IFOGs) shine out as they provide longer lifetime, quicker turn-on time, higher reliability, precision, and sensitivity. However, the fact that any environmental effects distorting the counter-propagating beams from travelling the identical path in a rotating loop induce phase differences apart from the Sagnac effect and cause error leaves them as an application which still needs to be improved. Therefore, we will start by paving the way with the studies we have conducted on the light source for improving its wavelength stability against temperature, and then we will steer our studies toward improving the quality of the fiber optic coil. Although IFOGs being a worldwide hot topic, most of the studies have been carried out by using quadrupole winding pattern, while only little is known when it comes to other winding patterns. Use of hexade-capole winding pattern paints a more promising picture and opens new doors in this research line. Being in the quest of finding a way to improve the performance of these sensors against such disturbing effects, we study and explore the thermal behaviours of the IFOGs built with fiber coils having different winding patterns. We demonstrate that the use of hexadecapole winding pattern overtowers the other winding patterns namely dipole, quadrupole, and octupole in the need of trimming as it presents lower absolute rate error; not only at a certain rate of temperature change but also under different rate of temperature changes. Moreover, we enrich our studies by further investigating the thermal behavior of these sensors, show the independency of Shupe effect in the direction of real rotation, and propose a novel method which eliminates the significance of the symmetry in fiber coil winding. We support our experimental findings with the simulations as well.