23 research outputs found
Thermodynamics of regular black holes with cosmic strings
In this article, the thermodynamics of regular black holes with a cosmic
string passing through it is studied. We will observe that the string has no
effect on the temperature as well as the relation between entropy S and horizon
area A.Comment: Accepted for publication in EPJ Plus, 6 page
The scale functions kit for first passage problems of spectrally negative Levy processes, and applications to the optimization of dividends
First passage problems for spectrally negative L\'evy processes with possible
absorbtion or/and reflection at boundaries have been widely applied in
mathematical finance, risk, queueing, and inventory/storage theory.
Historically, such problems were tackled by taking Laplace transform of the
associated Kolmogorov integro-differential equations involving the generator
operator. In the last years there appeared an alternative approach based on the
solution of two fundamental "two-sided exit" problems from an interval (TSE). A
spectrally one-sided process will exit smoothly on one side on an interval, and
the solution is simply expressed in terms of a "scale function" (Bertoin
1997). The non-smooth two-sided exit (or ruin) problem suggests introducing a
second scale function (Avram, Kyprianou and Pistorius 2004).
Since many other problems can be reduced to TSE, researchers produced in the
last years a kit of formulas expressed in terms of the " alphabet" for a
great variety of first passage problems. We collect here our favorite recipes
from this kit, including a recent one (94) which generalizes the classic De
Finetti dividend problem. One interesting use of the kit is for recognizing
relationships between apparently unrelated problems -- see Lemma 3. Last but
not least, it turned out recently that once the classic are replaced with
appropriate generalizations, the classic formulas for (absorbed/ reflected)
L\'evy processes continue to hold for:
a) spectrally negative Markov additive processes (Ivanovs and Palmowski
2012),
b) spectrally negative L\'evy processes with Poissonian Parisian absorbtion
or/and reflection (Avram, Perez and Yamazaki 2017, Avram Zhou 2017), or with
Omega killing (Li and Palmowski 2017)
A review on processing, mechanical and wear properties of Al matrix composites reinforced with Al2O3, SiC, B4C and MgO by powder metallurgy method
This study focused on improving the mechanical strength and wear resistance of aluminum matrix composites (AMCs) produced by powder metallurgy, which are critical in industrial applications. In this review study, studies involving the preparation and characterization of aluminum based composite materials reinforced with Al2O3, SiC, B4C and MgO powders using the powder metallurgy method have been comprehensively evaluated. Literature shows that changes in sintering time, temperature, and composition of powders can affect critical properties such as material density, hardness, and wear resistance. In general, the increase in sintering time and sintering temperature generally increased the density and reduced the amount of porosity of composite materials consisting of aluminum-based Al2O3, SiC, B4C and MgO powders. Increasing the compaction pressure generally increased the material density and created a more homogeneous structure. When the properties of each material were examined, it was determined that SiC and B4C provide higher strength, hardness and wear resistance, and therefore can be preferred especially in high-performance applications such as automotive, aerospace, defense industry and cutting tools
Optimization of Extraction Parameters of Phenolic Compounds from Sarcopoterium spinosum Leaves by Response Surface Methodology
The shrublands are very common in Urla-Çeşme-Karaburun peninsula located in the western point of Turkey. Prickly shrubby burnet (Sarcopoterium spinosum L.) is one of the common weed which has intensive thorns making its consumption for the local domestic animals. However, Sarcopoterium spinosum is a valuable and common medicinal plant in the Mediterranean region. Crude extract of S. spinosum leaves exhibited higher antioxidant activity, as 3143.5± 238.5 µM TEAC (Trolox Equivalent Antioxidant Capacity)/g dry weight (DW), when compared to other medicinal plants found in the literature. The aim of this study was to determine the effect of extraction parameters on the content and biological activity of the extract by response surface methodology (RSM) as well as to identify its major compounds. High Performance Liquid Chromatography (HPLC) was employed to investigate the phenolic content of S. spinosum extract. The composition of the phenolic contents including hyperoside and isoquercetin, the latter being the major component, in S. spinosum extract has been shown for the first time by HPLC. Antimicrobial activity of S. spinosum extract, identified by minimum inhibition concentration (MIC) assay, indicated that the crude extract had antifungal activity against Candida albicans
Optimization of Extraction Parameters of Phenolic Compounds from Sarcopoterium spinosum Leaves by Response Surface Methodology
The shrublands are very common in Urla-Çeşme-Karaburun peninsula located in the western point of Turkey. Prickly shrubby burnet (Sarcopoterium spinosum L.) is one of the common weed which has intensive thorns making its consumption for the local domestic animals. However, Sarcopoterium spinosum is a valuable and common medicinal plant in the Mediterranean region. Crude extract of S. spinosum leaves exhibited higher antioxidant activity, as 3143.5± 238.5 µM TEAC (Trolox Equivalent Antioxidant Capacity)/g dry weight (DW), when compared to other medicinal plants found in the literature. The aim of this study was to determine the effect of extraction parameters on the content and biological activity of the extract by response surface methodology (RSM) as well as to identify its major compounds. High Performance Liquid Chromatography (HPLC) was employed to investigate the phenolic content of S. spinosum extract. The composition of the phenolic contents including hyperoside and isoquercetin, the latter being the major component, in S. spinosum extract has been shown for the first time by HPLC. Antimicrobial activity of S. spinosum extract, identified by minimum inhibition concentration (MIC) assay, indicated that the crude extract had antifungal activity against Candida albicans.The shrublands are very common in Urla-Çeşme-Karaburun peninsula located in the western point of Turkey. Prickly shrubby burnet (Sarcopoterium spinosum L.) is one of the common weed which has intensive thorns making its consumption for the local domestic animals. However, Sarcopoterium spinosum is a valuable and common medicinal plant in the Mediterranean region. Crude extract of S. spinosum leaves exhibited higher antioxidant activity, as 3143.5± 238.5 µM TEAC (Trolox Equivalent Antioxidant Capacity)/g dry weight (DW), when compared to other medicinal plants found in the literature. The aim of this study was to determine the effect of extraction parameters on the content and biological activity of the extract by response surface methodology (RSM) as well as to identify its major compounds. High Performance Liquid Chromatography (HPLC) was employed to investigate the phenolic content of S. spinosum extract. The composition of the phenolic contents including hyperoside and isoquercetin, the latter being the major component, in S. spinosum extract has been shown for the first time by HPLC. Antimicrobial activity of S. spinosum extract, identified by minimum inhibition concentration (MIC) assay, indicated that the crude extract had antifungal activity against Candida albicans
Yunan ilerleyişi sırasında Durupınar (Totak) Köyü
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 Özer, Abdürrahim
Unutulmaya yüz tutmuş Kukla Tiyatrosu ve Tiyatro Tempo
Ankara : İhsan Doğramacı Bilkent Üniversitesi İktisadi, İdari ve Sosyal Bilimler Fakültesi, Tarih Bölümü, 2018.This work is a student project of the Department of History, Faculty of Economics, Administrative and Social Sciences, İhsan Doğramacı Bilkent University.The History of Turkey course (HIST200) is a requirement for all Bilkent undergraduates. It is designed to encourage students to work in groups on projects concerning any topic of their choice that relates to the history of Turkey. It is designed as an interactive course with an emphasis on research and the objective of investigating events, chronologically short historical periods, as well as historic representations. Students from all departments prepare and present final projects for examination by a committee, with 10 projects chosen to receive awards.Includes bibliographical references (pages 19-21).by Yasemin Başaran Doğan
Modified myocardial performance index for evaluation of fetal heart function and perinatal outcomes in intrahepatic pregnancy cholestasis
This study aims to evaluate cardiac function in cases of intrahepatic cholestasis of pregnancy (ICP) and compare results with those from healthy controls using the fetal left ventricular modified myocardial performance index (LMPI) and E-wave/Awave peak velocities (E/A ratio). Moreover, the association between LMPI values, total bile acid (TBA) levels, fetal Doppler measurements, and adverse neonatal outcomes was evaluated. A prospective cross-sectional study of 120 pregnant women was conducted, with 60 having ICP and the other 60 serving as controls. Doppler ultrasound and two-dimensional gray-scale fetal echocardiography were used to calculate the LMPI values and E/A ratios, respectively. The association between LMPI values and TBA levels, fetal Doppler measurements, and adverse neonatal outcomes was evaluated. Fetal LMPI values were significantly higher in the ICP group than in the control group (0.54 +/- 0.54 vs. 0.44 +/- 0.03; p 0.01). LMPI values were not associated with adverse neonatal outcomes in ICP cases. Fetal cardiac function (LMPI) is associated with increased bile acid levels in ICP. However, because it was not associated with adverse neonatal outcomes in ICP cases, the clinical significance of this finding is unclear. Further studies are required to evaluate the implications of increased LMPI