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Alternating-current losses in two-layer superconducting cables consisting of second-generation superconductors coated by U-shaped ferromagnetic materials

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Chinese Physics B 2013年第12期22卷 509-513页

作者： ahmet cicek Fedai Inanir Fedor Gmry Department of Physics Faculty of Arts and Sciences Mehmet Akif Ersoy University Department of Physics Faculty of Arts and Sciences Recep Tayyip Erdog an University Institute of Electrical Engineering Slovak Academy of Sciences Du'bravska' Cesta 9 842 39 Bratislava Slovakia

Alternating-current losses in a two-layer superconducting cable, each layer being composed of 15 closely-spaced rectangular wires made up of second-generation superconductors when the ends of wires are coated by either a non-magnetic or strong ferromagnetic material having a U profile is numerically investigated. Computations are carried out through the finite-element method. The alternating-current losses do not increase significantly if the relative permeability of the coating is increased three orders of magnitude, provided that the current amplitude is less than half of the critical current in a superconducting wire. However, the losses are much higher for ferromagnetic coating if the amplitude of the applied current oscillating at 50 Hz is close to the critical current. The ferromagnetic coating is seen to accumulate the magnetic field lines normally on its surfaces, while the field lines are parallel to the long axes of the wires, leading to more significant flux penetration in the coated regions. This facilitates a uniform low-loss current flow in the uncoated regions of the wires. In contrast, coating with a non-magnetic material gives rise to a considerably smaller current flow in the uncoated regions, whereas the low-loss flow is maintained in the coated regions. Moreover, the current flows in opposite directions in the coated and uncoated regions, where the direction in each region is converse for the two materials.

关键词： second-generation superconductor two-layer cable ferromagnetic coating U profile alternating-current losses

Optical, Energetic and Exergetic Analyses of Parabolic Trough Collectors

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Chinese Physics Letters 2007年第7期24卷 1787-1790页

作者： OZTURK Murat, cicek BEZiR Nalan OZEK Nuri Department of Physics Science-Literature Faculty Siileyman Demirel University Isparta TUrkey

Parabolic trough collectors generate thermal energy from solar energy. Especially, they are very convenient for applications in high temperature solar power systems. To determine the design parameters, parabolic trough collectors must be analysed with optical analysis. In addition, thermodynamics （energy and exergy） analysis in the development of an energy efficient system must be achieved. Solar radiation passes through Earth＇s atmosphere until it reaches on Earth＇s surface and is focused from the parabolic trough collector to the tube receiver with a transparent insulated envelope. A11 of them constitute a complex mechanism. We investigate the geometry of parabolic trough reflector and characteristics of solar radiation to the reflecting surface through Earth＇s atmosphere, and calculate the collecting totM energy in the receiver. The parabolic trough collector, of which design parameters are given, is analysed in regard to the energy and exergy analysis considering the meteorological specification in May, June, July and August in 1sparta/TUrkey, and the results are presented.

关键词： Exergetic Parabolic Collectors

Biofilter:a promising tool for mitigating methane emission from manure storage

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Journal of Arid Land 2011年第1期3卷 61-70页

作者： Nazim cicek Danny MANN Department of Biosystems Engineering University of Manitoba

Liquid manure storage may contribute to methane （CH4） emission and this emission can be greatly reduced if appropriate management practices are applied. Biofiltration has been used in other fields for mitigating greenhouse gas （GHG） emission （e.g., landfill） and shown promise for mitigation OH4 emis- sion from liquid manure storage. It has been reported that biofilter was capable of reducing 80% of CH4 emissions from manure storage. The OH4 removal efficiency is influenced by many factors, including OH4 and 02 concentrations, temperature, moisture, composition of the filter bed, nutrient, and empty bed resi- dency time （EBRT）. Biological conversion of methane of a biofilter is a slow process due to the low water solubility of methane. The residence times （EBRT） between 5 min and 5 h have been used, whereas a typical EBRT of 25 s is used for common biofilter applications. Temperature at which methanotrophic bac- teria are active ranges from 10℃ to 45℃. The maximum activity is found at around 30℃. The optimal filter bed water content depends on both the gas flow rate and the type of filter bed （soil, compost, etc.） and ranges from 30%-70% of the water holding capacity. Compost is the best material for filter bed. The optimal pH for methanotrophic bacteria is neutral to slightly acidic. Copper and nitrogen compounds especially nitrate are important nutrients to methanotrophic bacteria but their optimal concentrations have not been founded. Phosphorus and other elements such as potassium and manganese are reported to affect the performance of methanotrophic bacteria but need further confirmation.

关键词： biofilter greenhouse gas methane manure storage

A Computational Investigation of the Thermohydraulics of an EGS Project

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Journal of Thermal Science 2018年第5期27卷 405-412页

作者： BENIM Ali Cemal cicek Aydin EKER Arif Mert Department of Mechanical and Process Engineering Center of Flow Simulation (CFS) Düsseldorf University of Applied Sciences Department of Energy Raw Materials and Survey General Directorate of Mineral Research and Exploration HD Energy Inc.

A numerical analysis of the thermohydraulics of an enhanced geothermal system project is presented. The rock structures are modelled as porous medium, based on the computationally obtained hydraulic fracturing data of other authors. The influence of the domain size, grid resolution, temporal resolution and the discretization scheme is assessed to obtain a highly accurate numerical solution under the prevailing modelling assumptions. Based on the numerical model, different production scenarios are investigated and discussed. The relative positioning of the injection and production ports is also analyzed. It is shown that there is a considerable potential for optimizing the production rate and the port configuration to obtain the most favorable results for the production temperature, investment costs and operation costs.

关键词： enhanced geothermal system hot dry rock thermohydraulics numerical analysis

Lacidipine,thiamine pyrophosphate and their combination on the ocular ischemic syndrome induced by bilateral common carotid artery ligation

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International Journal of Ophthalmology(English edition) 2024年第5期17卷 815-821页

作者： Ibrahim cicek ahmet Mehmet Somuncu Durdu Altuner Bahadir Suleyman Renad Mammadov Seval Bulut Taha Abdulkadir Coban Tugba Bal Tastan Halis Suleyman Department of Ophthalmology Faculty of MedicineErzincan Binali Yildirim UniversityErzincan 24100Turkey Department of Pharmacology Faculty of MedicineErzincan Binali Yildirim UniversityErzincan 24100Turkey Department of Clinical Biochemistry Faculty of MedicineErzincan Binali Yildirim UniversityErzincan 24100Turkey Department of Histology and Embryology Faculty of MedicineErzincan Binali Yildirim University ErzincanErzincan 24100Turkey

AIM:To investigate the effect of lacidipine,thiamine pyrophosphate(TPP)and the combination of lacidipine and TPP against oxidative and inflammatory eye damage induced by bilateral common carotid artery ligation in ***:Male albino Wistar rats were categorized as those who underwent sham surgery(SG),right and left common carotid cross-clamping and unclamping procedure(CCU),lacidipine+CCU(LCCU),TPP+CCU(TCCU),and combination of lacidipine and TPP(LTC)+CCU(LTCCU).One hour before anesthesia,the LCCU(n=6)received lacidipine(4 mg/kg,orally)and the TCCU(n=6)received TPP(20 mg/kg,intraperitoneally).The SG(n=6)and CCU(n=6)received the same volume of distilled water from the same *** anesthesia(60 mg/kg ketamine,intraperitoneally),the necks of the rats were opened in the *** was created for 10min by placing clips on the right and left common carotid *** in the SG only underwent subcutaneous *** 10min,the clips were removed and reperfusion was achieved for six ***,the animals were euthanized(120 mg/kg ketamine,intraperitoneally)and the levels of oxidant,antioxidant and proinflammatory cytokines in the eye tissues were *** retinal tissue of the eye was also examined ***:Lacidipine,TPP,and LTC significantly prevent the increase in malondialdehyde,tumor necrosis factoralpha,interleukin-1β(IL-1β),and IL-6 levels,decrease in total glutathione levels,superoxide dismutase and catalase activities and histopathological retinal damage in eye tissue induced by bilateral common carotid artery ligation in *** impact of these drugs on protection is determined to be LTC>lacidipine>***:As a result of the study,it is concluded that LTC may be more effective than lacidipine and TPP alone in treating ocular ischemic syndrome.

关键词： ocular ischemic syndrome lacidipine thiamine pyrophosphate oxidative stress

Electrical and dielectric properties of Al/p-Si and Al/perylene/p-Si type diodes in a wide frequency range

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Chinese Physics B 2014年第1期23卷 519-524页

作者： ahmet Kaya akaya@turgutozal.edu.tr Physics Department Faculty of Sciences Gazi University Ankara 06500 Turkey

The perylene （C20H12） layer effect on the electrical and dielectric properties of Al/p-Si （MS） and Al/perylene/p-Si （MPS） diodes have been investigated and compared in the frequency range of 0.7 kHz-2 MHz. Experimental results show that C-V characteristics give an anomalous peak for two structures at low frequencies due to interface states （Nss） and series resistance （Rs）. The increases in C and G/o3 at low frequencies confirm that the charges at interface can easily follow an ac signal and yield excess capacitance and conductance. The frequency-dependent dielectric constant （er） and dielectric loss （e＇） are subtracted using C and G/co data at 1.5 V. The eI and e＂ values are found to be strongly dependent on frequency and voltage, and their large values at low frequencies can be attributed to the excess polarization coming from charges at traps. Plots of ln（o＇ac）-ln（w） for two structures have two linear regions, with slopes of 0.369 and 1.166 for MS, and of 0.077 and 1.061 for MPS, respectively. From the C 2-V characteristics, the doping acceptor atom concentration （NA） and barrier height （,~） for Schottky barrier diodes （SBDs） 1.303 ~ 1015 cm-3, and 1.10 and I. 13 eV, respectively. of MS and MPS types are also obtained to be 1.484 ~ 1015

关键词： organic-inorganic based Schottky diodes perylene (C20H12) interfacial layer electrical and di-electric properties frequency and voltage dependence

Effect of imperfect bonding on the dynamic response of a pre-stressed sandwich plate-strip with elastic layers and a piezoelectric core

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Acta Mechanica Solida Sinica 2017年第6期30卷 658-667页

作者： ahmet Dasdemir Department of Mathematics Kastamonu University Kuzeykent Campus 37150 Kastamonu Turkey

In this paper,we consider the dynamic response of a pre-stressed sandwich plate-strip with a piezoelectric core and elastic layers under the action of a time-harmonic force resting on a rigid *** investigation is carried out within the framework of the piecewise homogeneous body model by utilizing the exact equations of motion and relations of the linear theory of *** is assumed that there is a shear-spring-type imperfect contact between the layers,but a complete contact between the plate-strip and the rigid foundation.A mathematical model of the problem is constructed,and the governing equations of motion are solved by employing the finite element method（FEM）.Numerical results illustrating the influence of a change in the value of the shear-spring parameter on the dynamic response of the plate-strip are then presented.

关键词： Sandwich plate-strip Shear-spring-type imperfection Piezoelectric materials Initial stress Frequency response

New Apsidal Motion in Four Eccentric Eclipsing Binaries:V610 Car,V944 Cep,V2815 Ori and V1260 Tau

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Research in Astronomy and Astrophysics 2022年第11期22卷 69-77页

作者： ahmet Bulut Department of Physics Faculty of Arts and SciencesCanakkale Onsekiz Mart UniversityTerzioglu CampusTR-17020CanakkaleTurkiye Astrophysics Research Centre and Observatory Canakkale Onsekiz Mart UniversityTerzioglu CampusTR-17020CanakkaleTurkiye

This paper presents an apsidal motion *** apsidal motion analysis of the eccentric eclipsing binaries V610 Car(P=4.84 days),V944 Cep(P=6.56 days),V2815 Ori(P=2.13 days),and V1260 Tau(P=5.43 days)was performed using minima times from the O-C Gateway database,ASAS-3,ASAS-SN,and TESS,following Lacy’s *** rates of change of periastron longitude were found to be 0.0253±0.0041,0.0347±0.0015,0.0288±0.0010 and0.0294±0°.0079 cycle^(-1),*** the light curve study,the first photometric mass ratio of V944 Cep was found to be q=1.4994±0.0012.A new light curve of V944 Cep was obtained using TESS *** first absolute dimensions of V944 Cep were M_(1)=1.10±0.01 M_(⊙),M_(2)=1.64±0.02 M_(⊙),R_(1)=2.04±0.37 R_(⊙),R_(2)=3.77±0.67 R_(⊙)for the hotter primary component(T_(1)=4925 K),and M_(1)=1.04±0.01 M_(⊙),M_(2)=1.57±0.02 M_(⊙),R_(1)=2.26±0.36 R_(⊙),R_(2)=3.74±0.59 R_(⊙)for the cooler primary component(T_(1)=4475 K).For V610 Car,V944 Cep,V2815 Ori and V1260 Tau,the apsidal motion periods were found to be 188±26 yr,186±8 yr,73±3 yr and 182±38 yr,*** V944 Cep,the internal structural constants of the component stars log_(k2,obs)=-2.05±0.01 and log_(k2,theo)=-1.83 for hotter primary component and log_(k2,obs)=-1.97±0.01 and log_(k2,theo)=-1.89 for cooler primary component were calculated.

关键词： (stars:)binaries:eclipsing stars:fundamental parameters techniques:photometric

Adipose-derived stem cells in the treatment of hepatobiliary diseases and sepsis

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World Journal of Clinical Cases 2022年第14期10卷 4348-4356页

作者： Basri Satilmis Gizem Selen cicek Egemen cicek Sami Akbulut Tevfik Tolga Sahin Sezai Yilmaz Hepatology Research Laboratory Liver Transplant InstituteInonu UniversityMalatya 44000BattalgaziTurkey Department of Biochemistry Faculty of PharmacyInonu UniversityMalatya 44000BattalgaziTurkey Department of Anesthesiology and Reanimation Malatya Training and Research HospitalMalatya 44000YesilyurtTurkey Liver Transplant Institute InonuUniversityMalatya 44000BattalgaziTurkey

Determination of the mesenchymal stem cells is one of the greatest and most exciting achievements that tissue engineering and regenerative medicine have ***-derived mesenchymal stem cells(AD-MSC)are easily isolated and cultured for a long time before losing their stem cell characteristics,which are self-renewal and ***-MSC are mesenchymal stem cells that have pluripotent lineage *** are easily accessible,and the fraction of stem cells in the adipose tissue lysates is highest among all other sources of mesenchymal stem *** is also HLA-DR negative and can be transplanted allogenically without the need for *** advantages have popularized its use in many fields including plastic reconstructive ***,in the field of hepatology and liver transplantation,the progress is ***-MSC have the potential to modulate inflammation,ameliorate ischemia-reperfusion injury,and support liver and biliary tract *** are very important for the treatment of various hepatobiliary ***,the anti-inflammatory potential of these cells has paramount importance in the treatment of *** need alternative therapeutic approaches to treat end-stage liver ***-MSC can provide a means of therapy to bridge to definitive therapeutic alternatives such as liver *** we propose to review theoretic applications of AD-MSC in the treatment of hepatobiliary diseases and sepsis.

关键词： Adipose-derived stem cells Hepatobiliary diseases Sepsis Mesenchymal stem cells Theoretic application