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Perturbing the Stable Accretion Disk in Kerr and 4D Einstein-Gauss-Bonnet Gravities:Comprehensive Analysis of Instabilities and Dynamics

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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

Design of a large-scale model for wind tunnel test of a multiadaptive flap concept

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Chinese Journal of Aeronautics 2024年第2期37卷 58-80页

作者： Mürüvvet Sinem SICIM DEMIRCI Rosario PECORA Metin.orhan KAYA Aeronautical Engineering Department Istanbul Technical UniversityIstanbulTurkey Industrial Engineering Department University of Naples Federico IINapoliItaly

The design and application of morphing systems are ongoing issues compelling the aviation *** Clean Sky-program represents the most significant aeronautical research ever launched in Europe on advanced technologies for greening next-generation *** primary purpose of the program is to develop new concepts aimed at decreasing the effects of aviation on the environment,increasing reliability,and promoting eco-friendly *** ambitions are pursued through research on enabling technologies fostering noise and gas emissions reduction,mainly by improving aircraft aerodynamic *** the Clean Sky framework,a multimodal morphing flap device was designed based on tight industrial requirements and tailored for large civil aircraft *** flap is deployed in one unique setting,and its cross section is morphed differently in take-off and landing to get the necessary extra lift for the specific flight ***,during the cruise,the tip of the flap is deflected for load control and induced drag *** manufacturing the first flap prototype,a high-speed(Ma=0.3),large-scale test campaign(geometric scale factor 1:3)was deemed necessary to validate the performance improvements brought by this novel system at the aircraft *** the other hand,the geometrical scaling of the flap prototype was considered impracticable due to the unscalability of the embedded mechanisms and actuators for shape ***,a new architecture was conceived for the flap model to comply with the scaled dimensions requirements,withstand the relevant loads expected during the wind tunnel tests and emulate the shape transition capabilities of the true-scale *** strategies were developed to effectively morph the model during wind tunnel tests while ensuring the robustness of each morphed configuration and maintaining adequate stiffness levels to prevent undesirable deviations from the intended aerodynamic ***,

关键词： Morphing structures Smart aircraft Morphing flap Adaptive systems Finger-like ribs Wind tunnel tests Large-scale morphing archi-tectures Variable camber airfoil

Changes in Calcareous nannofossil Assemblages and Paleoenvironmental Interpretation of the Early Miocene Lice Formation, Kahramanmara? Basin, Turkey, East Mediterranean

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Acta Geologica Sinica(English Edition) 2024年第4期98卷 1021-1034页

作者： Caner KAYAÖZER Muazez Esra orhan Uğur TEMİZ Yozgat Bozok University DivanlıRoadYozgat 66900Turkey

This study investigated the calcareous nannofossil assemblages in detail from the early Miocene aged Lice Formation outcropping in the Kahramanmara? basin. The biostratigraphy of calcareous nannofossils was outlined and paleoenvironmental features determined. In 81 samples taken from three measured sections in the region, 17 calcareous nannofossil genus and 48 nannofossil species were identified. These calcareous nannofossil genus and species identified the Lice Formation as being in the CnM4 nannofossil biozone. The abundance and diversity of early Miocene calcareous nannofossil species varied in the measured sections, with the samples generally moderate-poor, apart from a few samples. The relative abundance of individuals of Cyclicargolithus floridanus, Coccolithus pelagicus, Reticulofenestra hagii and Sphenolithus moriformis species, with paleoecological importance identified in the study region, indicate that in early Miocene times, the basin in which the Lice Formation deposited was meso-eutrophic with excess nutrient input, temperate and generally stable shallow marine conditions.

关键词： paleoecology nannofossil Burdigalian East Mediterranean

伊尔加兹山脉冰缘地貌发育和土壤形成及其气候的影响(土耳其黑海西岸)

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Journal of Geographical Sciences 2024年第3期34卷 543-570页

作者： DEDE Volkan DEnGIZ orhan DEMIRAG TURAn inci TüRKES Murat SEnOL Hüseyin SERIn Soner Department of Geography Ardahan UniversityArdahan75002Türkiye Department of Soil Science and Plant nutrition Faculty of AgricultureOndokuz Mayıs UniversitySamsun55139Türkiye Department of Geography Faculty of Human and Social SciencesSamsun UniversitySamsun55080Türkiye Center for Climate Change and Policy Studies Boğaziçi Universityİstanbul34342Türkiye Faculty of Agriculture Department of Soil Science and Plant NutritionIsparta University of Applied SciencesIsparta32200Türkiye Institute of Social Sciences İstanbul Universityİstanbul34119Türkiye

The main aims of the current study are to determine the morphological features of the periglacial landforms(non-sorted step,mud circle,stony earth circle,thufur,and congeliturbation)located on the Ilgaz Mountains,examine the physicochemical and mineralogical properties with pedological processes of the soils,and assess of the effects of climatic conditions controlling the development of *** Ilgaz Mountains(2587 m a.s.l.),located in the Western Black Sea Region,within the Anatolian Mountains,are important in terms of periglacial landforms(mud circles,stony earth circles,thufurs,non-sorted steps,non-sorted stripes,congeliturbation deposits,and block currents).The descriptive statistics of 123 periglacial landforms measured by fieldworks were *** distribution of freezing and thawing in the Ilgaz Mountains throughout the year was evaluated,and it was found that freezing takes place between December and March,freezing-thawing takes place in April,May,October and november,and thawing takes place between June and *** to soil properties,organic matter content changes from 1.88%to 12.72%in non-sorted step soils,while it is between 2.03%and 12.24%in stony earth circle *** organic matter is observed to be close to congeliturbation deposits at lower ratios compared to non-sorted steps,stony earth circles and mud *** soil reactions on stony earth circles and non-sorted steps vary between slightly acidic and slightly *** the other hand,soil samples taken from the mud circles are different from those taken from the non-sorted steps and stony earth *** soil reaction is acidic,and pH changes between 4.86 and *** lime content also varies between 2.81%and 32.08%,with an average of 12.02%.The texture properties of soils are dominantly loam and clay loam,as in the non-sorted steps,stony earth circles,and mud *** their mineralogical properties,the XRD study was carried out to determine the primer mineral

关键词： periglacial landforms soil formation climate effect Ilgaz Mountains Türkiye

Chebyshev polynomial-based Ritz method for thermal buckling and free vibration behaviors of metal foam beams

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Applied Mathematics and Mechanics(English Edition) 2024年第5期45卷 891-910页

作者： n.D.nGUYEn T.n.nGUYEn Faculty of Civil Engineering Ho Chi Minh City University of Technology and EducationHo Chi Minh City 71309Viet Nam Faculty of Engineering and Technology Kien Giang UniversityChau Thanh 92000Viet Nam

This study presents the Chebyshev polynomials-based Ritz method to examine the thermal buckling and free vibration characteristics of metal foam *** analyses include three models for porosity distribution and two scenarios for thermal *** material properties are assessed under two conditions,i.e.,temperature dependence and temperature *** theoretical framework for the beams is based on the higher-order shear deformation theory,which incorporates shear deformations with higher-order *** governing equations are established from the Lagrange equations,and the beam displacement fields are approximated by the Chebyshev *** simulations are performed to evaluate the effects of thermal load,slenderness,boundary condition(BC),and porosity distribution on the buckling and vibration behaviors of metal foam *** findings highlight the significant influence of temperature-dependent(TD)material properties on metal foam beams'buckling and vibration responses.

关键词： Ritz method Chebyshev function buckling vibration metal foam beam higher-order beam theory(HOBT)

Compression properties of cost-efficient porous expanded clay reinforced AA7075 syntactic foams fabricated by industrial-oriented die casting technology

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China Foundry 2024年第1期21卷 60-70页

作者： İsmail Cem Akgün Çağın Bolat Ali Gökşenli Faculty of Mechanical Engineering Istanbul Technical University34437İstanbulTurkey Faculty of Engineering Samsun University55420SamsunTurkey

In today’s manufacturing industries,hard competition between rival firms makes it compulsory for researchers to design lighter and cheaper machine components due to the megatrends of cost-effectiveness and *** this point,aluminum syntactic foams(ASFs)are new-generation engineering composites and come into the upfront as a *** to their features like low density,sufficient elongation,and perfect energy absorption ability,these advanced foams have been considerably seductive for many industrial sectors *** this study,an industrial-oriented automatic die casting technology was used for the first time to manufacture the combination of AA7075/porous expanded clay(PEC).Micro evaluations(optical and FESEM)reveal that there is a homogenous particle distribution in the foam samples,and inspections are compatible with the other ASF ***,T6 aging heat treatment was operated on one half of the produced foams to explore the probable impact of aging on the compressive *** results show that PEC particles can be an alternative to expensive hollow spheres used in the previous ***,a favorable relationship is ascertained between the aging treatment and mechanical properties such as compression strength and plateau strength.

关键词： die casting porous materials metal matrix sytanctic foams expanded clay compressive deformation

Predicting effects of tunnel throttling of annular freeway vehicular flow by a continuum model

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Journal of Traffic and Transportation Engineering(English Edition) 2024年第4期11卷 733-746页

作者： Zhongmin Huang M.n.Smirnova n.n.Smirnov Zuojin Zhu Faculty of Engineering Science University of Science and Technology of ChinaHefei 230026China Institute of Plasma Physics Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China Faculty of Mechanics and Mathematics Lomonosov Moscow State UniversityMoscow 119992Russia

Fluid flow throttling is common in industrial and building services *** tunnel throttling of vehicular flow is caused by the abrupt number reduction of roadway lane,as the tunnel has a lower lane number than in the roadway normal *** predict the effects of tunnel throttling of annular freeway vehicular flow,a three-lane continuum model is ***Ⅲof the tunnel is completely blocked due to the need of tunnel rehabilitation,*** exists mandatory net lane-changing rate from laneⅢto laneⅡjust upstream of the tunnel entrance,which is described by a model of random number generated through a golden section *** net-changing rate between adjacent lanes is modeled using a lane-changing time expressed explicitly in algebraic *** paper assumes that the annular freeway has a total length of 100 km,a two-lane tunnel of length 2 km with a speed limit of 80 km/*** free flow speeds on lanesⅠ,ⅡandⅢare assumed to be 110,100 and 90 km/h *** on the three-lane continuum model,numerical simulations of vehicular flows on the annular freeway with such a tunnel are conducted with a reliable numerical method of 3rd-order *** results reveal that the vehicular flow has a smaller threshold of traffic jam formation in comparison with the case without tunnel *** fuel consumption can be estimated by interpolation with time averaged grid traffic speed and an assumed curve of vehicle *** vehicle fuel consumption is lane number dependent,distributes with initial density concavely,ranging from 5.56 to 8.00 *** throttling leads to an earlier traffic jam formation in comparison with the case without tunnel throttling.

关键词： Effects of tunnel throttling Vehicle fuel consumption Travel time Threshold of traffic jam formation Continuum model

Towards defining soil quality of Mediterranean calcareous agricultural soils:Reference values and potential core indicator set

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International Soil and Water Conservation Research 2024年第1期12卷 145-155页

作者： Germán A.Durán Daniel Sacristán Edelweis Farrús Jaume Vadell Institut de Recerca i FormacióAgrària i Pesquera de les Illes Balears C/Eusebi Estada14507009PalmaSpain Plant Biology Department University of Valencia46100BurjassotValenciaSpain Soil and Environmental Quality Department Centro de Investigaciones sobre Desertificación-CIDE(CSIC-Universitat de València-Generalitat Valenciana)Carretera Moncada-Náquera km 4.546113MoncadaValenciaSpain Universitat de les Illes Balears Cra.De Valldemossakm 7507122PalmaSpain

To avoid soil degradation,adapt to climate change and comply with the Sustainable Development goals 2030(Un General Assembly),establishing the quality/fertility of the agricultural soils of the Mediterranean region and evaluate how these evolve with time is *** enables adequate management practices to be *** Mediterranean calcareous region has received little attention in this sense,in spite its soil ***,24 different representative calcareous agricultural soils of the Mediterranean region,including the main management strategies of agricultural soils(rainfed and irrigated),were sampled from the island of Mallorca;and their physical,chemical and biological properties *** values obtained for most of the soil characteristics allowed to establish an initial approach to the reference values for the type of calcareous agricultural soils considered,and to clearly distinguish the effect of rainfed or irrigation management practices on soils properties and *** enzyme activities were not stimulated by the irrigation conditions assayed or they were only in dry conditions,suggesting optimum enzyme activities could be obtained when alternating dry and humid soil *** organic carbon,calcium carbonate and active lime revealed of significant importance in the collection of ***,the results obtained clearly indicate the heterogeneity of the region and its implications on the different soil ***,this study could serve as a starting point to adequately establish the quality(fertility)for Mediterranean calcareous agricultural soils and their reference values by conducting further research in this region and including more type of soils.

关键词： Soil fertility Mediterranean agricultural soils Calcareous soils Soil enzymes Soil management

Risk factors and mortality rates of carbapenem-resistant Gram-negative bacterial infections in intensive care units

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Journal of Intensive Medicine 2024年第3期4卷 347-354页

作者： Tulay orhan Kuloglu Gamze Kalin Unuvar Fatma Cevahir Aysegul Ulu Kilic Emine Alp Infection Control Committee Faculty of MedicineErciyes UniversityKayseriTurkey Department of Infectious Diseases Faculty of MedicineErciyes UniversityKayseriTurkey Programme of First and Emergency Aid Sakarya UniversitySakaryaTurkey Department of Infectious Diseases Faculty of MedicineYıldırım Beyazıt UniversityAnkaraTurkey

Background The prevalence of hospital-acquired infections caused by carbapenem-resistant gram-negative bacteria(CRGnB)is increasing *** risk factors have been associated with such *** present study aimed to identify risk factors and determine the mortality rates associated with CRGnB infections in intensive care *** This retrospective case-control study was conducted at Erciyes University Hospital(Kayseri,Turkey)between January 2017 and December *** and laboratory data were obtained from the Infection Control Committee data and record *** who had CRGnB infection 48–72 h after hospitalization were assigned to the case group,while those who were not infected with CRGnB during hospitalization formed the control *** factors,comorbidity,demographic data,and mortality rates were compared between the two *** Approximately 1449 patients(8.97%)were monitored during the active follow-up period;of those,1171 patients were included in this *** infection developed in 14 patients(70.00%)who had CRGnB colonization at admission;in 162(78.26%)were colonized during hospitalization,whereas 515(54.56%)were not *** was no significant difference in age,sex(male/female)or *** total length of hospital stay was statistically significantly longer(P=0.001)in the case group(median:24[interquartile range:3–378]days)than the control group(median:16[interquartile range:3–135]days).The rates of colonization at admission(25.5%;vs.10.6%,P=0.001)and mortality(64.4%vs.45.8%,P=0.001)were also significantly higher in the cases than in the control group,*** the univariate analysis,prolonged hospitalization,the time from intensive care unit admission to the development of infection,presence of CRGnB colonization at admission,transfer from other hospitals,previous antibiotic use,enteral nutrition,transfusion,hemodialysis,mechanical ventilation,tracheostomy,reintubation,central veno

关键词： Multidrug resistance Gram-negative bacteria Infection Intensive care units