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Research in Astronomy and Astrophysics 2024年第8期24卷 1-19页

作者： orhan Donmez College of Engineering and Technology American University of the Middle EastEgaila 54200Kuwait

The study of a disturbed accretion disk holds great significance in the realm of astrophysics,as such events play a crucial role in revealing the nature of disk structure,the release of energy,and the generation of shock ***,they can help explain the causes of X-ray emissions observed in black hole accretion disk *** this paper,we perturb the stable disk formed by spherical accretion around Kerr and Einstein-Gauss-Bonnet(EGB)black *** perturbation reveals one-and two-armed spiral shock waves around the black *** find a strong connection between these waves and the black hole spin parameter(a/M)and the EGB coupling constant(α).Specifically,we find that asαincreases in the negative direction,the dynamics of the disk and the waves become more ***,we observe that the angular momentum of the perturbing matter significantly affects mass accretion and the oscillation of the arising shock *** allows us to observe changes in QPO frequencies,particularly,perturbations with angular momentum matching the observed C-type low-frequency QPOs of the GRS 1915+105 ***,we conclude that the possibility of the occurrence of shock waves within the vicinity of GRS 1915+105 is substantial.

关键词： accretion-accretion disks-black hole physics-hydrodynamics-shock waves-X-rays binaries

The changing world under the corona virus threat-from human needs to SDGs and what next?

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Geo-Spatial Information Science 2021年第1期24卷 50-57,I0008页

作者： orhan Altan Ian Dowman Department of Geomatics Istanbul Technical UniversityIstanbulTurkey Department of Civil Environmental and Geomatic EngineeringUniversity College LondonLondonUK

The COVID-19(coronavirus)disease has affected over 100 countries in a matter of *** way humans live and work on planet Earth has changed profoundly over the last *** lives and livelihoods have been *** of working,shopping,and social interactions are all vastly different for most of *** do not know when the current crisis will end,or how far we will“return”to the way things were before the *** world is experiencing one of the most transformative moments of the last 100 *** social,economic,and political influences of the COVID-19 crisis have already been hugely momentous,we do not utterly understand *** ahead,we have inevitably had to make important public health,economic,governance,and ecological decisions with less information than usual and to reverse recently adopted policies,which can lead to an era of disruptive transformations to *** these historic times,we must understand the hidden reality of the earth system and attempt to transform our needs so that we all have a sustained future on our planet.

关键词： COVID-19 human needs social and scientific response millennium development goals sustainable development goals UN

Effect of Doping and High-Temperature Annealing on the Structural and Electrical Properties of Zn_(1-X)Ni_XO(0≤X≤0.15) Powders

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Journal of Materials Science & Technology 2011年第10期27卷 944-950页

作者： Hakan olak orhan Trkoglu Department of Chemistry Faculty of ScienceUniversity of Erciyes

This paper reported the synthesis, crystal structure and electrical conductivity properties of Ni-doped ZnO powders （i.e. Zn1-xNixO binary system, X=0, 0.0025, 0.005, 0.0075 and in the range 0.01≤X〈0.15）. I- phase samples, which were indexed as single phase with a hexagonal （wurtzite） structure in the Zn1-xNixO binary system, were determined by X-ray diffraction （XRD）. The widest range of the I-phase was determined as 0≤X≤0.03 at 1200℃; above this range the mixed phase was observed. The impurity phase was determined as NiO when compared with standard XRD data, using the PDF program. We focused on single f-phase ZnO samples which were synthesized at 1200℃ because of the widest range of solubility limit at this temperature. It was observed that the lattice parameters a and c of the I-phase decreased with Ni doping concentration. The morphology of the I-phase samples was analyzed with a scanning electron microscope. The electrical conductivity of the pure ZnO and single I-phase samples were studied by using the four-probe dc method at temperatures between 100 and 950℃ in air atmosphere. The electrical conductivity values of pure ZnO and 3 mol% Ni-doped ZnO samples at 100℃C were 2×10^-6 and 4.8×10^-6 Ω-***^-1, and at 950℃ they were 1.8 and 3.6 Ω-1cm-1, respectively. In other words, electrical conductivity increased with Ni doping concentration.

关键词： Ⅱ-Ⅵ semiconductors Zinc oxide and doped zinc oxide Four point probe method

Synthesis,Crystal Structural and Electrical Conductivity Properties of Fe-Doped Zinc Oxide Powders at High Temperatures

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Journal of Materials Science & Technology 2012年第3期28卷 268-274页

作者： Hakan Çolak orhan TÜrkoglu Department of Chemistry Science of FacultyUniversity of ErciyesKayseri38039Turkey Deparment of Chemistry Science of FacultyUniversity of C ank r KaratekinBall ca CampusC ank r18200Turkey

The synthesis,crystal structure and electrical conductivity properties of Fe-doped ZnO powders（in the range of 0.25-15 mol%） were reported in this paper.I-phase samples,which were indexed as single phase with a hexagonal（wurtzite） structure in the Fe-doped ZnO binary system,were determined by X-ray diffraction（XRD）.The solubility limit of Fe in the ZnO lattice is 3 mol% at 950℃.The above mixed phase was *** the impurity phase was determined as the cubic-ZnFe 2 O 4 phase when compared with standard XRD data using the PDF *** study focused on single I-phase ZnO samples which were synthesized at 950℃ because the limit of the solubility range is the widest at this *** lattice parameters a and c of the I-phase decreased with Fe-doping *** morphology of the I-phase samples was analyzed with a scanning electron *** grain size of the I-phase samples increased with heat treatment and doping *** electrical conductivity of the pure ZnO and single I-phase samples was investigated using the four-probe dc method at 100-950℃ in air *** electrical conductivity values of pure ZnO,0.25 and 3 mol% Fe-doped ZnO samples at 100℃ were 2×10-6,1.7×10-3 and 6.3×10-4 ***-1,and at 950℃ they were 3.4,8.5 and 4 ***-1,respectively.

关键词： II-VI semiconductors Zinc oxide and doped zinc oxide Four point probe method

A review of the day-ahead natural gas consumption in Denmark:starting point towards forecasting accuracy improvement

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International Journal of Coal Science & Technology 2021年第1期8卷 1-22页

作者： orhan AltuğKarabiber George Xydis Department of Business Development and Technology Aarhus UniversityBirk Centerpark 157400HerningDenmark

Natural gas consumption forecasting is crucial for transmission system operators,distribution system operators,traders,and other players in the *** work collects natural gas forecasting scientific works in accordance with the forecasting tool used by Energinet,the Danish transmission system *** work provides an analytical description on the long-term stability and security of the natural gas transmission system in *** work offers a detailed scientific directory on natural gas forecasting,presenting the so far vaguely described market in a more structured *** paper was focused on presenting the latest findings on identifying the selection each time of the appropriate prognostic model for each application based on:①the option for supporting double seasonality,②various exogenous variables,③suitability for day-ahead forecasting,and④ease of use and all these versus Energinet’s current model.

关键词： Natural gas Forecasting Natural gas supply chain Gas infrastructure

Binding energy of the donor impurities in GaAs-Ga_(1-x)Al_xAs quantum well wires with Morse potential in the presence of electric and magnetic fields

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Chinese Physics B 2016年第10期25卷 39-44页

作者： Esra Aciksoz orhan Bayrak Asim Soylu Department of Physics Akdeniz University Department of Physics Nigde University

The behavior of a donor in the GaAs–GaAlAs quantum well wire represented by the Morse potential is examined within the framework of the effective-mass approximation. The donor binding energies are numerically calculated for with and without the electric and magnetic fields in order to show their influence on the binding energies. Moreover, how the donor binding energies change for the constant potential parameters(De, re, and a) as well as with the different values of the electric and magnetic field strengths is determined. It is found that the donor binding energy is highly dependent on the external electric and magnetic fields as well as parameters of the Morse potential.

关键词： Morse potential electric field magnetic field the donor atom quantum well wire

A Survey on Belief Propagation Decoding of Polar Codes

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China Communications 2021年第8期18卷 133-168页

作者： Ahmet Cagrı Arlı orhan Gazi Digital Design and Verification Engineering Department Electra ICAnkaraTurkiye Electronic and Communication Engineering Cankaya UniversityAnkaraTurkiye

The increasing data traffic rate of wireless communication systems forces the development of new technologies *** high data rate,extremely low latency and improvement on quality of service are the main subjects of next generation 5G wireless communication systems which will be in the people’s life in the years of *** the newest and first mathematically proven forward error correction code,polar code is one of the best candidates among error correction methods that can be employed for 5G wireless *** aim of this tutorial is to show that belief propagation decoding of polar codes can be a promising forward error correction technique in upcoming 5G ***,we survey the novel approaches to the belief propagation based decoding of polar codes and continue with the studies about the simplification of these ***,early detection and termination methods and concept of scheduling are going to be presented throughout the ***,polar construction algorithms,error types in belief propagation based decoders and hardware implementations are going to be ***,this tutorial proves that the BP based decoding of polar codes has a great potential to be a part of communication standards.

关键词： polar codes belief propagation 5G

Seasonal size-segregated PM10 and PAH concentrations in a rural area of sugarcane agriculture versus a coastal urban area in Southeastern Florida, USA

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Particuology 2016年第5期14卷 52-59页

作者： orhan Sevimoglu Wolfgang F. Rogge Department of Civil and Environmental Engineering Florida International University 10555 W. Flagier Street Miami FL 33174 USA School of Engineering and Sierra Nevada Research Institute University of California at Merced 5200 North Lake Road Merced CA 95343 USA

Airborne particulate matter （PM） is of health and environmental concern not only in highly urbanized areas, but also in rural areas that are used for intensive agricultural purposes, In this study, PM size- segregated samples were collected simultaneously for 12 months in a small town （Belle Glade, Florida）, which is the center of a vast sugarcane growing area and at Delray Beach, a coastal city in Palm Beach County, Florida. During the winter sampling period, when sugarcane foliage is burned just before harvest- ing to reduce the amount of plant matter to be handled, PM10 levels were 50% or higher than otherwise measured, indicating that sugarcane harvesting and processing is a major local source for PM10. For the rest of the year, PM10 levels at both sites are similar, suggesting that ambient PM levels at both sites are impacted by the major urban centers in Southern Florida. During late July and early August, the PM10 levels at both sites were substantially elevated and revealed the typical red-brownish color of Saharan dust. This has been reported to occur frequently with suitable meteorological conditions over the Atlantic Ocean coupled with a Sahara dust storm event. During the sugarcane harvesting season at Belle Glade, the concentrations of PAHs associated with PM10 were up to 15 times higher than those measured during the summer growing season, indicating a substantially higher exposure of the rural population to these often mutagenic and carcinogenic compounds.

关键词： Size segregated ambient particles PM10 PAHs Biomass burning Rural versus urban Saharan dust

Seasonal variations of PM10 -- Trace elements, PAHs and Levoglucosan: Rural sugarcane growing area versus coastal urban area in Southeastern Florida, USA. Part II: Elemental concentrations

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Particuology 2019年第5期17卷 99-108页

作者： orhan Sevim oglu Wolfgang F. Rogge Department of Environmental Engineering Cebze Technical University Cebze Kocaeli 41400 Turkey School of Engineering and Sierra Nevada Research Institute University of California Merced. 5200 North Lake Road Merced CA 95343 USA

The largest sugarcane-growing area in the United States is in South Florida. An estimated 7 million tons of dry sugarcane leafy biomass is removed from the fields before harvest by burning the leaves off the sugarcane stalks. Preharvest sugarcane leaf foliage burning is a major source of airborne particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs), biogenic trace elements such as K, volatile hydrocarbons and other pollutants. In one harvesting period, approximately 22 million tons of C02, a greenhouse gas, is released, 7 million tons from leaf foliage preharvest burning alone and 15 million tons from burning sugarcane bagasse in the sugar mills for power generation. In this study, PMio was collected from Belle Glade, close to the sugarcane-growing area, and from Delray Beach, an urbanized area along the East Coast of Florida. The PM samples were analyzed for trace elements and close to organic compounds. To elucidate the importance of preharvest sugarcane biomass smoke emissions on air quality, 39 trace elements, 18 PAHs, and levoglucosan were selected to apportion ambient PM constituents. Al, Ca and to a great extend also Mg are the major soil-related trace elements and key markers for fugitive soil dust emissions. Similarly, sea salt aerosol blown from the Atlantic Ocean into Florida added appreciably to PMio trace elements concentration, especially Na and Cl. Approximately half of the sea salt aerosol (PMjo -portion) by mass is removed from the atmosphere during the transport of ocean air from Delray Beach to Belle Glade. Ambient acid displacement reactions caused a substantial portion of the Cl (30%) to be liberated from the sea salt aerosol to the atmosphere during transport as gaseous HC1. The PAH concentrations at Belle Glade were high when the biomass combustion markers levoglucosan and I< also showed the highest concentrations. This indicates that during the sugarcane harvest season, when leaf foliage is burned off just before harvest, most of

关键词： Urban versus rural Trace elements Sugarcane burning Rare earth elements Sea salt aerosol Potassium Levoglucosan PAHs

Assessment of air pollution genotoxicity by RAPD in Evernia prunastri L. Ach. from around iron-steel factory in Karabk, Turkey

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Journal of Environmental Sciences 2011年第7期23卷 1171-1178页

作者： Demet Cansaran-Duman orhan Atakol Smer Aras Refik Saydam National Public Health Agency Drug and Cosmetics Research Department Laboratories Department of Chemistry Faculty of Science University of Ankara Biotechnology Section Department of Biology Faculty of Science University of Ankara

Lichens are widely used in biomonitoring studies of air pollution, either as bioindicators of air quality or as bioaccumulators of atmospheric deposition. Over the past decade, several molecular techniques have been developed to provide information on diversity, genotoxicology, genetic relationships, etc. The heavy metal contents of Evernia prunastri samples were determined by atomic absorption spectrometry. The Random Amplified Polymorphic DNA Polymerase Chain Reaction （RAPD-PCR） method was used to describe the pattern of DNA band variation in the samples influenced by the environmental pollution. The study was designed to describe the level of pollution in an area contaminated with smoke and waste from an iron-steel factory, and to reveal the level of potential genotoxic agents around this source of pollution. The study also examined the suitability of the lichen samples for the detection of genotoxicity.

关键词： air pollution Evernia prunastri RAPD genotoxicity