2020 Cilt 25 Sayı 2

Permanent URI for this collectionhttps://hdl.handle.net/11452/12712

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    Dielectric properties of polyaniline-functionalized carbon nanotube/pdms nanocomposites
    (Bursa Uludağ Üniversitesi, 2020-07-11) Ünsal, Ömer Faruk; Altın, Yasin; Bedeloğlu, Ayşe Çelik
    In recent years, carbon nanotubes (CNTs) have emerged as materials that are often used in the preparation of polymer nanocomposites with conductive or advanced dielectric properties due to their unique properties including high temperature and electrical conductivity, which allows the production of very light and robust materials with a very high length-to-diameter ratio. However, during the preparation of polymeric nanocomposites with these materials, some problems are encountered. One of the major problems is that after preparing these conductive materials or adding them into the polymer, they tend to aggregate, forming agglomerate, due to their conductive structures. Therefore, in this study, firstly, multi-walled carbon nanotubes (MWCNTs) were functionalized with conductive form of polyaniline (PANI) and subsequently, the poly (dimethyl siloxane) (PDMS) polymer nanocomposite films with different concentrations of functionalized multi-walled carbon nanotubes were prepared. Then, the structural, morphological, electrical and dielectric properties of the films were characterized. As a result, with the addition of only 1.5% PANI-CNT, the dielectric constant of PDMS was increased by 47-fold at 1 Hz. The dielectric films like presented here can be used in capacitors, flexible electronics, dielectric elastomers and artificial muscle applications.
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    The influences of altering the mixing conditions on the properties of polymer modified bitumen: An overview
    (Bursa Uludağ Üniversitesi, 2020-04-30) Özdemir, Derya Kaya; Topal, Ali; Şengöz, Burak
    Modification of bitumen by different modifiers, causes the morphological, rheological and chemical characterisation differences related to the following three main factors: the type of the polymer, bitumen components and blending conditions. Manufacturing conditions can be investigated in several groups such as; mixing temperature, duration of mixing and shear rate (mixing speed). These manufacturing conditions are the key parameters, since they act an important role on the properties of the final product. These key parameters and their effects have always been an interesting topic for the researchers, because they may have some consequences like aging of the sample, degradation of the polymer or sometimes less absorption of the polymer by bitumen etc. This study aims to present the influences of mixing conditions on different properties of the bituminous mixtures with the help of reviewing the previous studies in the literature.
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    A new criterion for stability of neutral-type hopfield neural networks with constant delays
    (Bursa Uludağ Üniversitesi, 2020-02-25) Faydasıçok, Özlem
    This paper makes some contributions to the stability problem of neutral-type Hopfield neural network model having a constant time delay in states of neurons and a constant neutral delay in the time derivatives of states of neurons. With the help of a suitable Lyapunov functional, a novel stability criterion is derived for neutral-type Hopfield neural network model. This stability criterion only requires to check the positive defineteness of the matrices involving the system elements of this type of neural networks. The presented stability condition proved to be independently of these time and neutral delays. Therefore, this condition can be easily justified by applying the properties of some certain matrices. A numerical example for this type of neutral systems is studied to show the applicability of the presented stability result.
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    Structural strengthening of second row passenger seat frame developed for M1 category vehicles
    (Bursa Uludağ Üniversitesi, 2020-08-19) Erkul, Semih; Balcı, Semih
    The issue of security in the automotive industry is becoming more and more important day by day and intensive studies are carried out in this regard. It is vital that automobile seats have to meet security regulations to assure optimum passenger safety. This article investigates the design changes of a passenger seat required to meet and exceed the Economic Commission for Europe (ECE) R-14 regulation. ECE R-14 contains a lot of restrictions to secure adequate safety-belt anchorages endurance for vehicles. Various design scenarios have been created to improve the performance of the seat. The CAD models have been designed in CATIA V5 and validated using Hyperworks software. Then, physical tests were also conducted with prototypes to compare outputs with FEA results.