Filtreler
Filtreler
Bulunan: 76 Adet 0.001 sn
Koleksiyon [20]
Tam Metin [2]
Yayın Türü [5]
Yazar [20]
Yayın Yılı [11]
Konu Başlıkları [20]
Yayıncı [1]
Yayın Dili [1]
Dergi Adı [20]
Electrodeposition of Si–DLC nanocomposite film and its electronic application

Basman N. | Uzun R. | Gocer E. | Bacaksiz E. | Kolemen U.

Article | 2018 | Microsystem Technologies24 ( 5 ) , pp.2287 - 2294

In this study, a silicon doped diamond-like carbon (DLC) nanocomposite film was deposited electrochemically and it was used to fabricate an Ag/Si–DLC/p-Si metal–interlayer–semiconductor (MIS) Schottky diode. Methanol (CH3OH) was used as carbon and tetraethoxysilane (Si(OC2H5)4) as Si source, respectively. Morphology of the film was observed by scanning electron microscopy and continuous surface with numerous lumps spread randomly was observed. Structural and chemical composition analyses of the film were carried out by Raman and X-ray photoelectron spectroscopy. Typical D and G bands of DLC films were not observed in the Raman spect . . .rum due to abundance of Si–C bonds. Silicon incorporation promoted the film deposition and increased sp3 bonds in the film. Current–Voltage (I–V) measurement was conducted to obtain parameters of the MIS diode. The diode exhibited a good rectifier behavior with ~ 103 rectification ratio. In the forward bias semi-logarithmic I–V plot, two linear regions with different slopes were observed. Such behavior was modelled by two parallel diodes and attributed to different conduction mechanism. The main electrical parameters, such as barrier height, ideality factor and series resistance were calculated by I–V and Cheung–Cheung methods. The Si–DLC nanocomposite film acted as barrier height modifier in the MIS diode. © 2017, Springer-Verlag GmbH Germany, part of Springer Nature Daha fazlası Daha az

A new perspective for quintic B-spline based Crank-Nicolson-differential quadrature method algorithm for numerical solutions of the nonlinear Schrödinger equation

Başhan A. | Uçar Y. | Murat Yağmurlu N. | Esen A.

Article | 2018 | European Physical Journal Plus133 ( 1 ) , pp.2287 - 2294

In the present paper, a Crank-Nicolson-differential quadrature method (CN-DQM) based on utilizing quintic B-splines as a tool has been carried out to obtain the numerical solutions for the nonlinear Schrödinger (NLS) equation. For this purpose, first of all, the Schrödinger equation has been converted into coupled real value differential equations and then they have been discretized using both the forward difference formula and the Crank-Nicolson method. After that, Rubin and Graves linearization techniques have been utilized and the differential quadrature method has been applied to obtain an algebraic equation system. Next, in ord . . .er to be able to test the efficiency of the newly applied method, the error norms, L 2 and L ? , as well as the two lowest invariants, I 1 and I 2 , have been computed. Besides those, the relative changes in those invariants have been presented. Finally, the newly obtained numerical results have been compared with some of those available in the literature for similar parameters. This comparison clearly indicates that the currently utilized method, namely CN-DQM, is an effective and efficient numerical scheme and allows us to propose to solve a wide range of nonlinear equations. © 2018, Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature Daha fazlası Daha az

On quaternions with generalized Fibonacci and Lucas number components

Polatli E. | Kesim S.

Article | 2015 | Advances in Difference Equations2015 ( 1 ) , pp.2287 - 2294

In this paper, we give the exponential generating functions for the generalized Fibonacci and generalized Lucas quaternions, respectively. Moreover, we give some new formulas for binomial sums of these quaternions by using their Binet forms. © 2015, Polatli and Kesim.

Assessment of spatial variations of particulate matter (PM10 and PM2.5) in Bahrain identified by air quality index (AQI)

Jassim M.S. | Coskuner G.

Article | 2017 | Arabian Journal of Geosciences10 ( 1 ) , pp.2287 - 2294

The rapid urbanization, industrialization, modernization, and the frequent Middle Eastern dust storms have negatively impacted the ambient air quality in Bahrain. The objective of this study is to identify the most critical atmospheric air pollutants with emphasis on their potential risk to health based on calculated AQI (air quality index) values using EPA approach. The air quality datasets of particulate matters (PM10 and PM2.5), ozone (O3), sulfur dioxide (SO2), nitrogen dioxide (NO2), and carbon monoxide (CO) were measured in January 2012 and August 2012 using five mobile air quality monitoring stations located at different gove . . .rnorates. The results of this study demonstrated that PM10 and PM2.5 are the most critical air pollutants in Bahrain with PM2.5 prevailing during January 2012 and PM10 prevailing during August 2012. The corresponding AQI categories were utilized to evaluate spatial variability of particulate matters in five governorates. The impact of meteorological factors such as ambient air temperature, wind speed, relative humidity, and total precipitation on ambient air quality were discussed. The analysis demonstrated that the highest PM10 concentrations were observed in the Northern Governorate while the highest PM2.5 concentrations were observed in the Capital, Central, and Northern Governorates during August 2012. It was observed that the levels of PM2.5 pollution were higher within proximity of the industrial zone. The results suggested that the average PM2.5/PM10 ratio in August 2012 was lower than in January 2012 due to the Aeolian processes. This study concludes that higher wind speed, total precipitation, relative humidity rates, and lower ambient air temperature in January 2012 assisted with the dissipation of particulate matter thus lowering the pollution levels of both PM10 and PM2.5 in comparison to August 2012. © 2016, Saudi Society for Geosciences Daha fazlası Daha az

Tetanus in adults: results of the multicenter ID-IRI study

Tosun S. | Batirel A. | Oluk A.I. | Aksoy F. | Puca E. | Bénézit F. | Ural S.

Article | 2017 | European Journal of Clinical Microbiology and Infectious Diseases36 ( 8 ) , pp.1455 - 1462

Tetanus is an acute, severe infection caused by a neurotoxin secreting bacterium. Various prognostic factors affecting mortality in tetanus patients have been described in the literature. In this study, we aimed to analyze the factors affecting mortality in hospitalized tetanus patients in a large case series. This retrospective multicenter study pooled data of tetanus patients from 25 medical centers. The hospitals participating in this study were the collaborating centers of the Infectious Diseases International Research Initiative (ID-IRI). Only adult patients over the age of 15 years with tetanus were included. The diagnosis of . . .tetanus was made by the clinicians at the participant centers. Izmir Bozyaka Education and Research Hospital’s Review Board approved the study. Prognostic factors were analyzed by using the multivariate regression analysis method. In this study, 117 adult patients with tetanus were included. Of these, 79 (67.5%) patients survived and 38 (32.5%) patients died. Most of the deaths were observed in patients >60 years of age (60.5%). Generalized type of tetanus, presence of pain at the wound area, presence of generalized spasms, leukocytosis, high alanine aminotransferase (ALT) and C-reactive protein (CRP) values on admission, and the use of equine immunoglobulins in the treatment were found to be statistically associated with mortality (p < 0.05 for all). Here, we describe the prognostic factors for mortality in tetanus. Immunization seems to be the most critical point, considering the advanced age of our patients. A combination of laboratory and clinical parameters indicates mortality. Moreover, human immunoglobulins should be preferred over equine sera to increase survival. © 2017, Springer-Verlag Berlin Heidelberg Daha fazlası Daha az

Assessing seismic response of a 2D roller-compacted concrete dam under variable reservoir lengths

Kartal M.E. | Cavusli M. | Sunbul A.B.

Article | 2017 | Arabian Journal of Geosciences10 ( 22 ) , pp.1455 - 1462

Finite element method (FEM) is effectively used for evaluating roller-compacted concrete (RCC) dams, especially in high seismicity zones. The aim of this study is to investigate the effect of various reservoir lengths on the seismic response of a selected RCC dam under strong ground motion effects. Six different reservoir lengths, the lengths varies from h/2 to 10h (h, the height of dam), are used within finite element models. The hydrodynamic pressure of the reservoir water is modelled with the 2D fluid finite elements based on the Lagrangian approach. The horizontal and vertical components of the 1989 Mw 6.9 Loma Prieta earthquake . . . are utilized in numerical analyses. The non-linear time-history analyses of those six models are investigated by using Drucker-Prager material model. According to the numerical analysis, it is obvious that the seismic behavior of the RCC dams is considerably dependent on the reservoir length. By increasing the length, we have obtained higher displacement values, which exist until the reservoir length reaches the 3h; at increased lengths, the values remain stable. This result proposes that 3h reservoir length is adequate to assess the seismic response of RCC dams. The principal tensile stresses are relatively lower in non-linear analysis compared to linear analyses. However, the principal compression stresses are close to each other in linear and non-linear analyses. The results imply that the non-linear response is influential on the total seismic response of a dam, which cannot be neglected in numerical analysis. © 2017, Saudi Society for Geosciences Daha fazlası Daha az

On the harmonic and hyperharmonic Fibonacci numbers

Tuglu N. | Kızılateş C. | Kesim S.

Article | 2015 | Advances in Difference Equations2015 ( 1 ) , pp.1455 - 1462

In this paper, we study the theory of the harmonic and the hyperharmonic Fibonacci numbers. Also, we get some combinatoric identities like as harmonic and hyperharmonic numbers and we obtain some useful formulas for Fn, which is concerned with finite sums of reciprocals of Fibonacci numbers. We obtain the spectral and Euclidean norms of circulant matrices involving harmonic and hyperharmonic Fibonacci numbers. © 2015, Tuglu et al.

Microfungal community structure from forest soils in Northern Thrace Region, Turkey

Kara Ö. | Asan A.

Article | 2007 | Annals of Microbiology57 ( 2 ) , pp.149 - 155

The soil fungi in the pure stand of oak (Quercus petraea), beech (Fagus orientalis), and pine (Plnus nigra) were investigated by the dilution plate method at Yildiz Mountain in Thrace region. The mycobiota, as well as the number of isolates per plate, was determined at various soil depths. Principal component analysis of the soil profiles indicated that there was variation in mycobiota composition and the variation was attributed to differences among the ecosystems. When comparing conifer and hardwood soils, using Sorenson's similarity index, fungal community composition corresponded more closely between the hardwood stands than wit . . .h the conifer stand. Fungal community composition appears to be influenced by the organic compounds entering soil from plant litter Daha fazlası Daha az

Hydrothermal and supercritical ethanol processing of woody biomass with a high-silica zeolite catalyst

Alper K. | Tekin K. | Karagöz S.

Article | 2019 | Biomass Conversion and Biorefinery9 ( 4 ) , pp.669 - 680

The effects of high-silica ZSM-5 on the yields, as well as compositions, of bio-oil and solid residue obtained from oak wood sawdust were investigated. The catalyst, in concentrations from 5 to 40 wt% of the raw lignocellulose material, was tested in hydrothermal (HT) and supercritical ethanol (SCE) media. The highest bio-oil yields were 11.0 and 32.4 wt% for HT and SCE processing, respectively, and were obtained by using 20 wt% ZSM-5. After the noncatalytic and catalytic HT processing and noncatalytic SCE processing of lignocellulose, the major products were phenols, whereas esters were the major products in the bio-oils obtained f . . .rom the catalytic SCE processing of oak wood sawdust. The use of ZSM-5 increased the relative contents of the ester compounds in the bio-oils from the SCE processing, while the catalyst did not significantly change the composition of the bio-oils produced from the HT processing of oak wood sawdust. The highest heating values of the bio-oils were 27.11 and 25.65 MJ kg-1 for HT and SCE processing, respectively, and were obtained from the noncatalytic runs. The amount of recovered carbon in the bio-oils from the catalytic runs was higher than that from the noncatalytic runs for both HT and SCE processing. The carbon content of the solid residues for both HT and SCE processing decreased with the use of a catalyst. An increase in the catalyst concentration led to a decrease in the carbon content of the solid residues in SCE and HT processing. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature Daha fazlası Daha az

A stability assessment of the rockfall problem around the Gökgöl Tunnel (Zonguldak, Turkey)

Geniş M. | Sakız U. | Çolak Aydıner B.

Article | 2017 | Bulletin of Engineering Geology and the Environment76 ( 4 ) , pp.1237 - 1248

The stability of rock slopes is an important area of interest in civil and mining engineering. This study investigated rockfall occurring around the Gökgöl tunnel along the Zonguldak-Ankara roadway. Extensive field studies, including determination of geological description of the rock mass, scan-line surveys on discontinuities, identification of slope profiles, measurement of actual fallen block dimensions, and sampling procedures, were carried out. The study area and its surroundings are part of a Lower Carboniferous limestone formation. The assessments based on field studies indicated that two joint sets and a bedding plane were t . . .he main types of discontinuity. Two slope profiles were then created by considering the most frequently encountered rock fall events. The present study aimed to investigate the rockfall potential in this area by means of numerical analyses. For this purpose, RocFall software based on the lumped-mass method was utilized. Based on these analyses, traffic safety is threatened by potential rockfall. In Case I, a 30 % portion of the falling blocks reached the side of the main road, while about 70 % of them remained on the slope. However, falling blocks reached the end of the road in Case II. The study area requires some protection measures, such as the construction of retaining barriers and steel mesh to hold small size rock blocks. As a result, barrier heights to hold falling blocks were calculated as 0.5 m and 4 m for Case I and Case II, respectively. Barrier heights sufficient to hold falling rocks were determined using numerical analysis. In Case II, from such analyses, the energy required for a protection barrier for 1000 kg was found to be 200 kJ. © 2016, Springer-Verlag Berlin Heidelberg Daha fazlası Daha az

Production and characterization of microporous activated carbon from cherry laurel (Prunus laurocrasus L.) stone: application of H2 and CH4 adsorption

Toprak A.

Article | 2019 | Biomass Conversion and Biorefinery , pp.1237 - 1248

In this study, a series of activated carbons with high surface area and micropore volume were obtained by KOH activation of cherry laurel (Prunus laurocrasus L.) stone in several temperatures (500–850 °C). The physical properties of the obtained activated carbons were characterized by SEM, XRD, N2 (77 K), and CO2 (273 K). The relation between CH4 (298 K) and H2 (77 K) adsorption capacities of activated carbons in low pressures with surface area and micropore volumes was determined. Based on the results, it was found that all the activated carbons match the type I (Langmuir) isotherm; in other words, they show a characterization of m . . .icropore. The maximum BET surface area was found out as 1928 m2/g in the sample of AC850. The maximum adsorption capacity of H2 (77 K) and CH4 (298 K) in low pressure (1 atm) was found out in the sample of AC800 with 2.90 wt% and 1.47 mmol/g, respectively. It was determined that narrow micropore has a significant contribution to CH4 and H2 adsorption in low pressures, while BET surface area and total pore volume do not have a direct relation with adsorption. However, it was identified that the pores between 5 and 7 Å have a significant contribution to CH4 adsorption of activated carbons, while the pores between 5 and 10 Å have a similar effect on H2 adsorption. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature Daha fazlası Daha az

Vitamin B12 deficiency evaluation and treatment in severe dry eye disease with neuropathic ocular pain

Ozen S. | Ozer M.A. | Akdemir M.O.

Article | 2017 | Graefe's Archive for Clinical and Experimental Ophthalmology255 ( 6 ) , pp.1173 - 1177

Purpose: This study aims to understand the effect of vitamin B12 deficiency on neuropathic ocular pain (NOP) and symptoms in patients with dry eye disease (DED). Methods: Patients with severe DED (without receiving topical artificial tears treatment) and ocular pain were enrolled (n = 90). Patients with severe DED and vitamin B12 deficiency (group 1, n = 45) received parenteral vitamin B12 supplement + topical treatment (artificial tears treatment + cyclosporine), and patients with severe DED and normal serum vitamin B12 level (group 2, n = 45) received only topical treatment (artificial tears treatment + cyclosporine). Patients wer . . .e evaluated by the ocular surface disease index (OSDI) questionnaire, 3rd question (have you experienced painful or sore eyes during last week?) score of OSDI as a pain determiner and pain frequency measure), tear break up time (TBUT), and Schirmer’s type 1 test. We compared the groups’ OSDI, TBUT, and Schirmer’s test recordings at the first visit and after 12 weeks retrospectively. Results: The OSDI score, 3rd OSDI question score, TBUT, and Schirmer’s test results improved after 12 weeks (p < 0.001 for each group). The mean vitamin B12 level at enrollment was 144.24 ±43.36 pg/ml in group 1 and 417.53 ±87.22 pg/ml in group 2. The mean vitamin B12 level in group 1 reached to 450 ±60.563 pg/ml after 12 weeks of treatment. The mean score changes between the groups were not statistically significant; however, the decrease in the OSDI questionnaire score (-30.80 ±5.24) and 3rd OSDI question score (-2.82 ±0.53) were remarkable in group 1 (Table 2). The mean TBUT increase was +7.98 ±2.90 s and Schirmer’s test result increase was +12.16 ±2.01 mm in group 1. The mean TBUT increase was +6.18 ±1.49 s and Schirmer’s test result increase was +6.71 ±1.47 mm in group 2. Conclusions: These findings indicate that vitamin B12 deficiency is related with NOP. It may be important to consider measuring the serum vitamin B12 level in patients with severe DED presenting with resistant ocular pain despite taking topical treatment. © 2017, Springer-Verlag Berlin Heidelberg Daha fazlası Daha az

6698 sayılı Kişisel Verilerin Korunması Kanunu kapsamında yükümlülüklerimiz ve çerez politikamız hakkında bilgi sahibi olmak için alttaki bağlantıyı kullanabilirsiniz.

creativecommons
Bu site altında yer alan tüm kaynaklar Creative Commons Alıntı-GayriTicari-Türetilemez 4.0 Uluslararası Lisansı ile lisanslanmıştır.
Platforms