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DIRECTIONAL DERIVATIVE OF VECTOR FIELD AND REGuLAR CuRVES ON TIME SCALES

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Applied Mathematics and Mechanics(English Edition) 2006年第10期27卷 1349-1360页

作者： emin zyilmaz Department of Mathematics Ege University35100IzmirTurkey

The general idea in this paper is to study curves of the parametric equations where the parameter varies in a so-called time scale, which may be an arbitrary closed subset of the set of all real numbers. We introduce ... 详细信息

关键词： time scale nabla derivative regular curve tangent line vector field

A novel reusable anti-COVID-19 transparent face respirator with optimized airflow

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Bio-Design and Manufacturing 2021年第1期4卷 1-9页

作者： Hussain Alenezi Muhammet emin Cam Mohan Edirisinghe Department of Mechanical Engineering University College LondonTorrington PlaceLondon WC1E 7JEUK Department of Manufacturing Engineering College of Technological StudiesPAAET13092 Kuwait CityKuwait Center for Nanotechnology and Biomaterials Application and Research Marmara University34722 IstanbulTurkey

This novel face mask is designed to be a reusable respirator with a small and highly efficient disposable fabric *** material requirements are reduced by 75%compared to traditional designs and allow repeated cleaning or *** probability of virus particle inhalation is reduced using novel air filtration pathways,through square-waveform design to increase filter *** enters the mask from right and left side filters,while the area in front of the mouth is *** epoxy is used for a transparent frame,allowing lip-reading,and mask edges contain a silicone seal preventing bypass of the *** mask is manufactured using silicone molds,eliminating electricity requirements making it economical and viable in developing *** fluid dynamics numerical studies and Fluent ANSYS software were used to simulate airflow through the filter to optimize filter air path geometry and validate mask design with realistic human *** breathing cycle was represented as a transient function,and N95 filter specifications were selected as a porous *** novel design achieved 1.2×10^(−3) kg s^(−1),20%higher than human requirements,with air streamlines velocity indicating local high speed,forcing and trapping virus particles against filter walls through centrifugal forces.

关键词： COVID-19 Mask Prototype Flow Pressure Temperature

Dynamics of the Moving Ring Load Acting in the System“Hollow Cylinder+Surrounding Medium”with Inhomogeneous Initial Stresses

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Computers, Materials & Continua 2019年第8期61卷 503-534页

作者： Surkay DAkbarov emin TBagirov Muslum Ozisik Yildiz Technical university Department of Mechanical EngineeringYildiz CampusBesiktasIstanbul34349Turkey Institute of Mathematics and Mechanics of National Academy of Sciences of Azerbaijan BakuAz141Azerbaijan Yildiz Technical university Department of Mathematical EngineeringDavutpasa CampusEsenlerIstanbul34220Turkey

This paper studies the influence of the inhomogeneous initial stress state in the system consisting of a hollow cylinder and surrounding elastic medium on the dynamics of the moving ring load acting in the interior of the *** is assumed that in the initial state the system is compressed by uniformly distributed normal forces acting at infinity in the radial inward direction and as a result of this compression the inhomogeneous initial stresses appear in the *** appearance of the initial stresses,the interior of the hollow cylinder is loaded by the moving ring load and so it is required to study the influence of the indicated inhomogeneous initial stresses on the dynamics of this moving *** influence is studied with utilizing the so-called threedimensional linearized theory of elastic waves in elastic bodies with initial *** solution of the corresponding mathematical problems,the discrete-analytical solution method is employed and the approximate analytical solution of these equations is *** results obtained within this method and related to the influence of the inhomogeneous initial stresses on the critical velocity of the moving load and on the response of the interface stresses to this load are presented and *** particular,it is established that the initial inhomogeneous initial stresses appearing as a result of the action of the aforementioned compressional forces cause to increase the values of the critical velocity of the moving load.

关键词： Inhomogeneous initial stresses dynamics of a moving load critical velocity hollow cylinder elastic medium ring load

Microstructure,mechanical properties,and corrosion resistance of an explosively welded Mg-Al composite

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Journal of Magnesium and Alloys 2022年第4期10卷 1086-1095页

作者： Mustafa Acarer Bilge Demir Burak Dikici emin Salur Department of Metallurgical and Materials Engineering Technology FacultySelcuk UniversityKonya 42075Turkey Department of Mechanical Engineering Karabuk UniversityKarabuk 78100Turkey Department of Metallurgical and Materials Engineering Atatürk UniversityErzurum 25240Turkey

In this study,an attempt was made to manufacture an AZ31–Al5005 laminated composite by explosive welding.A mixture of ammonium nitrate(90%),fuel oil(5%),and TNT(5%)was used as the *** detonation velocity of the explosive material was approximately 3100 m•s^(−1).The microstructure and mechanical and corrosion properties of the joint were comparatively *** characterisation of the joint was conducted by optical microscopy(OM),scanning electron microscopy with energy-dispersive spectroscopy(SEM-EDS),high-resolution transmission electron microscopy(HR-TEM),and X-ray diffraction(XRD).The mechanical properties were determined using micro-Vickers hardness,tensile,and Charpy impact *** addition,electrochemical tests were conducted on the AZ31–Al5005 laminated composite and the individual components to determine their corrosion *** corrosion behaviours of the structures were determined in a 3.5%NaCl solution at room temperature using potentiodynamic scanning(PDS).The metallurgical structure and mechanical properties of the joints were within the acceptable limits.

关键词： corrosion welded Microstructure

Surface Pencil with a Common Line of Curvature in Minkowski 3-Space

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Acta Mathematica Sinica,English Series 2014年第12期30卷 2103-2118页

作者： Evren ERGN Ergin BAYRAM emin KASAP Ondokuz Mayis university arsamba Chamber of Commerce Vocational School Ondokuz Mayis university Faculty of Arts and SciencesMathematics Department

In this paper, we analyze the problem of constructing a surface pencil from a given spacelie （timelike） line of curvature. using the Frenet frame of the given line of curvature in Minkowski 3-space, we express the surface pencil as a linear combination of this frame and derive the necessary and sufficient conditions for the coefficients to satisfy the line of curvature requirement. We illustrate this method by presenting some examples.

关键词： Minkowski space line of curvature surface pencil

Giant saccular aneurysm of the left main coronary artery

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Journal of Geriatric Cardiology 2013年第1期10卷 110-112页

作者： Esref Tuncer ugur Onsel Turk emin Alioglu Department of Cardiology Central Hospital 2/2 Bayrakli Izmir 35050 Turkey

Coronary aneurysms represent anomalies identified in 0.15%–4.9%of patients undergoing coronary angiography. At present, there is no uniform definition of this pathology. Aneurysms of the left main coronary artery (LMCA) are extremely uncommon, with an incidence of 0.1%. It has been demonstrated that atherosclerosis is the main cause of these anomalies in adults, and Kawasaki disease in children and adolescents. Other causes include connective tissue disorders, trauma, vasculitis, congenital, mycotic, and idiopathic. These dilated sections of the coronary artery are not benign pathology because they are subject to spasm, thrombosis, and subsequent distal embolism, spontaneous dissection and rupture. Treatment options include anticoagulation, custom-made covered stents, reconstruction, resection, and exclusion with bypass. Our report on an old case illustrates the giant saccular LMCA aneurysm leading to myocardial ischemia due to coronary steal phenomenon.

关键词： Coronary aneurysm Coronary angiography Coronary artery disease

Forced Vibration of the Non-Homogeneously Pre-Stressed System Consisting of the Hollow Cylinder and Surrounding Medium

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Computer Modeling in Engineering & Sciences 2019年第10期121卷 315-348页

作者： Surkay D.Akbarov emin T.Bagirov Department of Mechanical Engineering Yildiz Technical UniversityYildiz Campus34349BesiktasIstanbulTurkey Institute of Mathematics and Mechanics of the National Academy of Sciences of Azerbaijan 37041BakuAzerbaijan.

The paper deals with the study of the influence of the non-homogeneous prestresses in the system consisting of the hollow cylinder and surrounding elastic medium on the frequency response of this system caused by the time-harmonic ring load acting in the interior of the *** axisymmetric problem is considered and it is assumed that in the initial state,the system is compressed in the radial direction with homogeneously distributed static forces as a result of which,non-homogeneous pre-stresses(or initial stresses)appear in *** is also assumed that after these pre-stresses appear in the interior of the cylinder,the point-located(with respect to the axial coordinate directed along the cylinder’s central axis)additional time-harmonic ring load ***,it is required to determine how the pre-stresses influence the frequency response of the system to the noted additional time-harmonic *** influence,which is the non-linear effect,is studied within the scope of the so-called three-dimensional linearized equations and relations of the theory of elastic waves in pre-stressed *** solution to the corresponding boundary value problems is found by employing the discrete analytical solution method and numerical results on the influence of the pre-stresses on the frequency response of the interface stresses which appear as a result of the action of the additional time-harmonic forces,are presented and *** particular,it is established that the pre-stresses mentioned above cause to decrease the magnitude of the interface dynamic stresses appearing as a result of the additional time-harmonic loading.

关键词： Non-linear effect inhomogeneous initial stresses frequency response timeharmonic ring load hollow cylinder surrounding medium

Determination of threshing and separation unit performance of rosemary(Rosmarinus officinalis)plants

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International Journal of Agricultural and Biological Engineering 2021年第6期14卷 237-243页

作者： Deniz Yilmaz Mehmet emin Gökduman Department of Agricultural Machinery&Technology Engineering Faculty of AgricultureIsparta University of Applied SciencesIspartaTurkey

Rosemary(Rosmarinus officinalis L.)is an important perennial medicinal and aromatic plant belonging to the Lamiaceae *** is widely produced in Turkey for its oil which can be extracted from the plants when flowers are in *** Turkey,a significant amount of domestic and foreign trade of rosemary is *** 2018-2020,2088 t of rosemary plants were imported,while in the same years 2077 t were *** this study,the performance indexes of a threshing and separating unit designed according to the physicomechanical properties of the rosemary were *** operating parameters of the machine were determined at three different moisture contents and adjusted according to the harvest moisture *** threshing efficiency,work efficiency,power requirement,and specific energy consumption values of the threshing unit were determined,while separating efficiency,work efficiency and specific power consumption of separating unit of the developed system were *** to the study results,the threshing efficiency of the rosemary plant varied between 44.00%and 96.97%.Work efficiency of the thresher varied between 1.18 and 15.34 kg/*** requirements and specific energy consumption of the threshing unit were obtained as 0.19-1.05 kW and 0.02-0.37 kW·h/h,*** the other hand,the separating efficiency of the separating unit for the rosemary plant varied between 44.27%and 85.24%.Maximum and minimum values of work efficiency were found as 0.75 kg/h and 5.52 kg/*** power consumption of the unit ranged from 3.95 to 39.95 kW/kg.

关键词： rosemary mechanization threshing separating design Turkey

Development of a measurement system for noise and vibration of combine harvester

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International Journal of Agricultural and Biological Engineering 2020年第6期13卷 104-108页

作者： Deniz Yilmaz Mehmet emin Gökduman Department of Agricultural Machinery&Technology Engineering Faculty of AgricultureIsparta University of Applied SciencesIspartaTurkey

Combine harvesters are important in that grain and legumes directly affect the production *** the other hand,it forms an important branch of the agricultural machinery *** are many unknown constraints on machines when harvesting with a combine harvester,including the noise and vibration that occur in the combine harvester *** study aims to analyze noise and vibration in conventional combine harvesters using *** accelerometers were installed on each side of the concave and two microphones were used to register the noise of the threshing *** result showed that effects of machine speeds(3.5 km/h,4.5 km/h and 5.5 km/h)and rotor speeds(950 r/min,850 r/min and 950 r/min)were significantly important for the mean range values of the left and right accelerometer in the X,Y and Z *** machine’s speed and rotor speed were not significantly important for the mean range values of the left and right microphones.

关键词： measurement combine harvester sensors noise vibration