Biography:

In the past Ali Kaya has collaborated on articles with Özlem Kandemir. One of their most recent publications is Effects of various parameters on dynamic characteristics in adhesively bonded joints. Which was published in journal Materials Letters.

More information about Ali Kaya research including statistics on their citations can be found on their Copernicus Academic profile page.

Ali Kaya's Articles: (4)

Effects of various parameters on dynamic characteristics in adhesively bonded joints

AbstractAdhesively bonded lap joints are used extensively in various industries. Some disadvantages like holes, thermal effects occurring in the bolted, welded, riveted, and soldered joints are not in question in adhesively bonded joints. Strong adhesive materials used in bonding have been greatly developed in recent years, and then the properties of lightness, sealing, corrosion resistance, heat and sound isolation, damping, and quickly mounting facility have been highly improved. In this work, effects of various dynamic characteristics in the adhesively bonded joints subjected to dynamic forces are investigated using the finite element method. The investigation is conducted on a three-dimensional model. The finite element model of the joint is obtained using isoparametric three-dimensional elements having eight nodes with three degrees of freedom each. Mesh generation is accomplished automatically in a computer.The joint is modeled as a thin plate clamped from the left side. The in-plane vibration analysis is constructed. First, the natural frequencies and mode shapes are obtained, and then point and transfer receptances are extracted, employing structural damping. It is observed that the damping greatly decreased the resonance amplitudes.

Original articleElevation of procalcitonin level in patients with pulmonary tuberculosis and in medical staff with close patient contact

AbstractBackground. Several studies have shown that serum procalcitonin levels increase conspicuously in acute and systemic inflammatory diseases. However, there is insufficient information concerning its activity in chronic infectious diseases such as tuberculosis. In this study, we aimed to assess serum level of procalcitonin in patients with active pulmonary tuberculosis and in medical staff at high risk due to close patient contact (high-risk staff).Methods. For this purpose, 30 patients (6 female, 24 male) and 20 staff (8 female, 12 male) were evaluated. Twenty eight healthy blood donors (9 female, 19 male) made up the control group.Results. Serum procalcitonin level in patients with tuberculosis was 0.76±0.20 ng/mL. Procalcitonin levels in active tuberculosis patients and staff were not significantly different (p = 0.381); however, differences between active tuberculosis patients and control group were significant (p<0.001). In addition, serum procalcitonin levels were also different in staff and control groups (p<0.001).Conclusions. This study showed that procalcitonin levels increased both in patients with pulmonary tuberculosis and in the staff. This result considered that procalcitonin could be a good indicator of inflammation in patients with chronic diseases and in persons exposed to long-lasting infections.

On conifolds and D3-branes

AbstractWe search for Ricci flat, Kähler geometries which are asymptotic to the cone whose base is the space T11 by working out covariantly constant spinor equations. The metrics we find are singular in the interior and introducing parallel D3-branes does not form regular event horizons cloaking the naked singularities. We also work out a supersymmetric ansatz involving only the metric and the 5-form field corresponding to D3-branes wrapping over the nontrivial 2-cycle of T11. We find a system of first-order equations and argue that the solution has an event horizon and the ADM mass per unit volume diverges logarithmically.

Infrared logarithms in minisuperspace inflation

AbstractWe examine the emergence of the infrared logarithms in the cosmological perturbation theory applied to the minisuperspace scalar slow-roll inflation. Not surprisingly, in the single scalar field model the curvature perturbation ζ is conserved and no ln⁡aB behavior appears, where aB(t) is the background scale factor of the universe. On the other hand, in the presence of a spectator scalar the n'th order perturbation theory gives an (ln⁡aB)n correction to ζ. However, a nonperturbative estimate shows that ζ actually becomes the sum of a constant and a mildly evolving ln⁡aB pieces.

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