bluuebunny/crossref_metadata_2025 huggingface dataset:
Kadınların sosyodemografik özelliklerine göre kontraseptif yöntem kullanma durumları ve bu yöntemleri tercih nedenleri
Authors: Kutlu Ruhuşen , Sayın Seher , Uçar Mehmet , Aslan Raziye , Demirbaş Oğuz
Published: September 2014

Amaç: Bu araştırmanın amacı 18-49 yaş grubu evli kadınların sos-yodemografik özelliklerine göre kontraseptif yöntem kullanma durumları ve bu yöntemleri tercih nedenlerini belirlemektir.
Yöntem: Tanımlayıcı ve kesitsel tipteki bu araştırma 2 Ekim - 2 Kasım 2012 tarihleri arasında Konya il merkezinden rasgele seçilen 3 Aile Sağlığı Merkezinde yapılmıştır. Çalışma bu zaman diliminde Aile Sağlığı Merkezlerine herhangi bir nedenle başvuran 416 evli kadında yapılmıştır. Standart bir ankette katılımcıların sosyodemografik özellikleri ve kontraseptif yöntem ile ilgili deneyimleri sorgulandı.
Bulgular: Katılımcıların yaş ortalaması 30,7±6,9, ortalama çocuk sayısı 2,2±1,4, ortalama evlilik süresi 10,1±7,2 ve evlenme yaşı 20,6±2,5 yıl idi. Katılımcıların %11,1’i okuryazar değil, %22,4’ü okuryazar, %34,6’sı ilkokul, % 8,2’si ortaokul, % 13,7’si lise ve %10,1’i üniversite mezunu idi. Yüzde 66’sı (s=252) şehir merkezinde yaşıyor, %80,8’i ev hanımı ve tamamı evli idi. Katılımcıların %71,4’ü (s=297) modern bir yöntem, %13,5’i (s=56) geleneksel yöntem kullanıyor, %15,1’i (n=63) ise herhangi bir yöntem kullanmıyordu. En sık kullanılan yöntemler kondom (%42,3), rahim içi araç (RİA) (%17,1) ve hap (%8,9) idi. İlkokul ve üzeri eğitim sahibi olmak, şehirde yaşamak ve eşin eğitimi ile modern yöntem kullanımı anlamlı olarak artarken (p<0,001); yaş, gravida, ekonomik statü, aile tipi ve eşinin mesleği ile bir ilişkisi yoktu (p>0,05).
Sonuç: Kadınlar arasında aile planlaması yöntemleri kullanma oranı oldukça yüksekti. Çalışmamızda hem kadınların hem de eşlerinin eğitim seviyeleri yükseldikçe modern aile planlaması yöntemlerinin kullanımının arttığı görülmüştür.
Tek doz Doksisiklin kullanımına bağlı gelişen özofagus ülseri: Bir olgu sunumu
Authors: Sayın Seher , Kutlu Ruhuşen , Sayın Serhat , Ataseven Hüseyin
Published: September 2014

İlaca bağlı özofagus ülseri literatürde sık görülmemekle birlikte yol açabileceği komplikasyonlar açısından önemlidir. Doksisiklin yeterli miktarda su ile alınmaz ise veya alındıktan kısa süre sonra yatılırsa özofagusta mukozal hasara neden olur. Bu olguda akne nedeniyle doksisiklin tedavisi başlanmış 24 yaşındaki kadın hasta sunuldu. Hasta ilacın ilk dozundan sonra retrosternal yanma, disfaji semptomlarıyla başvurdu. Yapılan üst gastrointestinal sistem endoskopisinde özofagus 1/3 orta bölümünde 2 santimetrelik bir segmentte yüzeyel ülserasyonlar görüldü. Anamnez ve endoskopik bulgularla, hastaya doksisiklin kullanımına bağlı ilaç özofajiti teşhisi konuldu. Doksisiklin tedavisi ve oral alımı kesildi. İntravenöz sıvı tedavisi, sukralfat ve lansoprazol tedavisi başlandı. İlerleyen günlerde hastanın şikâyetleri azalarak kayboldu. Olgumuzda olduğu gibi, ilacın süresinden bağımsız olarak tek doz kullanım sonrasında dahi özofageal ülser gelişebilmektedir.
Olgu sunumu: Şizofren hastanın renal kolik tablosundan doğuma giden hikayesi
Authors: Tetik Burcu Kayhan , Eray İrep Karataş , Öztaş Özlem , Öztürk Seval
Published: September 2014

Şizofreni; tanımı, sınırları, klinik belirtileri ve gidişi bakımından çeşitlilik gösteren, her toplumda ve sosyo-ekonomik ortamda görülebilen ciddi bir ruhsal bozukluktur. Hastalık sıklıkla erkeklerde 15-25, kadınlarda ise 25-35 yaşlarında başlar. Çocuk doğurmanın psikiyatrik hastalığı olan kadınların sağlığını koruması ya da psikiyatrik hastalıklara yatkınlık yaratması ile ilgili çok az şey bilinmektedir. Olgumuzda kendisi ve ailesi tarafından hamile olduğu bilinmeyen ve herhangi bir gebelik takibi olmayan hastanın, sağlıklı erkek bebek dünyaya getirmesi ilginç geldiği için vakamızı paylaştık.
Relationship between mitral annular and left atrial function as assessed by three-dimensional speckle-tracking echocardiography in healthy volunteers. Results from the MAGYAR-Healthy Study
Authors: Domsik Péter , Kalapos Anita , Lengyel Csaba , Orosz Andrea , Forster Tamás , Nemes Attila
Published: September 2014

Introduction: Left atrium is a heart chamber with dinamic motion communicating with left ventricle through the mitral valve and its annulus. Aim: The aim of the present study was to analyse whether relationships could exist between three-dimensional speckle-tracking echocardiography-derived morphologic and functional parameters of the left atrium and mitral annulus in healthy subjects. Method: The present study comprised 35 healthy volunteers. Maximum (Vmax) and minimum (Vmin) left atrial volumes and left atrial volume before atrial contraction (VpreA) were measured, and several functional parameters based on these volumes were calculated in all cases. Morphologic and functional characteristics of the mitral annulus were also determined. Results: While Vmax showed correlations with both systolic and diastolic mitral annulus parameters, Vmin-VpreA correlated with only systolic ones. While total left atrial stroke volume correlated with both systolic and diastolic mitral annular parameters, passive left atrial stroke volume showed correlations only with diastolic ones. Conclusions: Correlations exist between left atrial and mitral annular morphological and functional characteristics in healthy subjects. Orv. Hetil., 2014, 155(38), 1517–1523.
Study of transonic effect of flows around slender bodies of revolution and plane profiles
Authors: Ngoc Hoang Thi Bich
Published: September 2014

Transonic effect with presence of local supersonic terminated by shock wave is not wished. In spite of wishes or not, the appearance of shock waves is not avoided. Strong shock waves cause losses, even a grand decrease of aerodynamic quality in fluid-solid interaction. However, under certain conditions, transonic effect increases the drag and at the same time increases the lift leading the amelioration of aerodynamic quality. This work uses numerical methods and established programs for solving differential equations of the axisymmetric flow and the plane flow to study the influence of transonic effects for the two cases.
Thermoelastic stability of thick imperfect functionally graded plates
Authors: Tung Hoang Van , Duc Nguyen Dinh
Published: September 2014

This paper investigates buckling of thick functionally graded plates with initial geometrical imperfection under thermal loadings. The equilibrium, stability, and compatibility equations of an imperfect functionally graded plate are derived using the third order shear deformation theory. Material properties are assumed to be temperature-independent and graded in the thickness direction according to a simple power law distribution in terms of the thickness coordinate variable. By Galerkin method, the resulting equations are solved to obtain closed-form solutions of critical buckling temperature difference. Two types of thermal loading, uniform temperature rise and nonlinear temperature change across the thickness are considered. Buckling analysis for a simply supported rectangular imperfect functionally graded plate shows effects of geometry and material parameters, shear deformation and imperfection on critical buckling temperature.
Study on optimal parameter of vibration reduction system TMD-D and DVA for an inverted pendulum type structures and application to tower in the ocean
Authors: Dien Khong Doan , Chinh Nguyen Duy
Published: September 2014

Nguyen Dong Anh, Khong Doan Dien and Nguyen Duy Chinh in [1] have studied the vibration of inverse pendulum system installed with the vibration reduction system TMD-D and DVA. These results implemented by numerical simulation for the articulated tower in the ocean show that the obtained oscillations in some cases with installed absorber increase the amplitude of vibration when compared to the case without absorber. It is a fact that when simulation is employed, the parameters of TMD-D and DVA are chosen arbitrarily without optimal design. In the paper, the authors investigate to find the optimal parameters of the TMD-D and DVA absorbers in order to optimally reduce the vibration for the inverse pendulum system. These research results are applied to reduce the vibration for the articulated tower in the ocean.
Numerical-experimental investigation on vibration and bending failure of stiffened composite plates
Authors: Quoc Tran Huu , Thinh Tran Ich
Published: September 2014

In this paper, free vibration and bending of laminated stiffened glass fiber/polyester composite plates with laminated open section (rectangular or T shaped) and closed section (hat shaped) of stiffeners have been studied by finite element method and experiment. A nine-noded isoparametric element with nine degrees of freedom per node is developed for the plates. The stiffener element is a three-noded isoparametric beam element with five degrees of freedom per node and the stiffeners can be positioned anywhere within the plate element. The natural frequencies of the laminated stiffened plates are determined experimentally by Dewebook device and DasyLab 7.0 software. The results calculated by computational model for above plates under different boundary conditions are in good agreement with experiments. The failure problems of these stiffened glass fiber/polyester composite plates are also investigated.
Collision of four balls aligned
Authors: Mekki Othman Ben , Frémond Michel
Published: September 2014

The collision of four balls aligned is analyzed in this paper. This study is based on the fundamental idea that a system formed by rigid bodies is deformable, since its shape changes because the relative distances of the different bodies change. A simple linear constitutive law, described by a pseudo-potential of dissipation completed by the condition of the impenetrability between the balls, is used. we consider the case where three balls falls on a very massive obstacle. The first ball, considered of very light mass, bounces with a velocity extensively superior to its fall velocity. This is sometimes called the superball phenomenon. This phenomenon is produced according to different cases such as the interaction between the first ball and the massive obstacle must be presented. Introducing an interaction between the first ball and the massive obstacle through the second or the third ball, the superball phenomenon is produced for all cases of evolutions after the collision. For every cases of evolutions of the balls after the collision, has been investigated the relations on the physical parameters which insure the superball phenomenon. These relations are obtained on the basis of the fundamental hypothesis: the mass of the first ball is very small whereas the mass of the massive obstacle is very large.
The theoretical research of an upward two-phase flow with phase's changes in a vertical well
Authors: V. S. Shagapov , S. L. Borodin , A. A. Gubaidullin , Ngoc Hai Duong , N. G. Musakaev
Published: September 2014

By methods of mechanics of multiphase systems the mathematical model describing an upward gas-and-oil flow in a vertical well is constructed. The model considers phase's changes, deposition of oil paraffin on the elevating column's walls of the well, influence of an installation of electrical centrifugal pumps on parameters of the gas-and-oil flow, and also heat exchange of the well with surrounding rock. It is shown, that at the using of an installation of electrical centrifugal pumps and variation of its metering characteristic, depth of its setting, it is possible to achieve the optimum temperature mode on all the well's height and to prevent by it formation of paraffin deposits.
Buckling analysis of simply supported composite laminates subjected to an in-plane compression load by a novel mesh-free method
Authors: Bui Tinh Quoc
Published: September 2014

Buckling analysis of composite laminates under an in-plane compression load based on the mesh-free Galerkin Kriging method is presented. The moving Kriging interpolation (MK) technique possessing the delta property is employed to construct the shape functions, and thus no special techniques for imposing the essential boundary conditions are required. The present formulation is based on the Kirchhoff plate theory. The applicability, the accuracy and the effectiveness of the method are illustrated through a number of numerical examples. The results calculated by the proposed method are compared with those of existing reference solutions available in the literature and very good agreements are observed. It can be said that the proposed method can be considered as an alternative numerical technique in terms of meshfree methods.
Experimental study of laminar separation phenomenon combining with numerical calculations
Authors: Hung Nguyen Manh , Bich Ngoc Hoang Thi
Published: September 2014

The separation is much more sensitive for laminar flow than for turbulent flow. These remarks have been attested for both subsonic and supersonic flows. However, they are not applicable to transonic flows when there are interactions between boundary layer and shock wave. Along with the Reynolds number, the Mach number is a necessary dimensionless parameter for the condition and the mechanism of separations. The report presents one part of studies on laminar separation with Mach number of incompressible flow. The laminar regimes correspond to flows through wind turbine blades. Our experimental work for laminar separation phenomenon was carried out in a subsonic open circuit wind tunnel by taking photographs. The accuracy of experimental results basically depends on the accuracy of wind tunnel and the quality of smoke on density and constitutive materials. Experimental results permit to determine the position of separation and the form of turbulent region followed from the separation point. Numerical studies were simultaneously realized. Based on obtained experimental and numerical results, the report presents also the comparison between the laminar separation and the turbulent separation.
Experimental study on mechanical properties for a three-phase polymer composite reinforced by glass fibers and titanium oxide particles
Authors: Duc Nguyen Dinh , Minh Dinh Khac
Published: September 2014

Nowadays, composite materials are applied in many fields. The physico-mechanical properties of the material can be improved by adding reinforced fibers and particles. Many scientists pay attention to the calculation for elastic modules of three-phase composite materials. This report presents the experimental results for some elastic modules of three-phase polymer composite reinforced with glass fibers and titanium oxide particles of different volume ratios. A comparison between experimental and theoretical results shows good agreement.
Mathematical modelling and control of the evolution of dynamic systems interacting with medium
Authors: Zakovorotny V. L. , Dong Anh Nguyen , Tung Pham Dinh
Published: September 2014

The article proposes a new method of mathematical modeling evolutional systems interacting with medium. A cutting process or tribo-space formed in the contact area of two conjugate mechanical subsystems is considered as medium. The features of the medium depend not only on state coordinates of systems but also on trajectories. It is obtained that the parameters of the medium are performed as integral operators of equations like Volterra equations of 2nd type. The problems of control of evolutional systems are being analyzed.
Study of separation phenomenon in transonic flows produced by interaction between shock wave and boundary layer
Authors: Bich Ngoc Hoang Thi , Hung Nguyen Manh
Published: September 2014

For compressible flows, the transonic state depends on the geometry, Mach number and the incidence. This effect can produce shock wave. Some studies showed that the interaction between shock wave and boundary layer concerns separation phenomenon. Studies in this report demonstrate conditions of separation in transonic flow and that it is not any interaction between shock wave and boundary layer which can cause boundary layer separation. The studies also show that maximum Mach number in the local supersonic region is not a unique factor influencing the separation, and the separation in transonic flows can occur at the incidence of 0\(^{\circ}\). For the calculation of viscous transonic flows, we use Fluent software with serious treatment of application operation based on the physical nature of phenomenon and the technique of numerical treatment. For the calculation of invicid transonic flows, we built a code solving the full potential equation with verification for accuracy. Results calculated from Fluent have been seriously compared with results of present program and published results in order to assure the accuracy of application operation in the domain of investigation. separation in transonic flows; shock wave and boundary layer
An object-oriented design method to implement the mechatronic system control by using hybrid automata and real-time UML
Authors: Quang Vu Duy , Hien Ngo Van
Published: September 2014

In this paper, we present a method, which is based on hybrid automata and Real-Time Unified Modeling Language (UML) to analyze and design the control parts of mechatronic systems with input or output events and signals in order to effectively gather their structure and behaviour. We introduce step-by-step analysis and design activities of a controlled mechatronic system such as the specification of its hybrid automaton and realization hypotheses, the identification of object collaborations of this system, the identification of main control capsules, their ports and communication protocols, with their static and dynamic links. These activities are conducted by specializing the iterative life cycle of system development. Then, we indicate important hypotheses, which allow all the identified capsules of this system to make their evolutions. We apply this method to develop an Electro-Hydraulic Governor (EHG) system, which allows the frequency of an electro-hydraulic station to be stabilized.
An efficient homogenization method using the trigonometric interpolation and the fast fourier transform
Authors: Nguyen Ngoc-Trung , Licht Christian , Kweon Jin-Hwe
Published: September 2014

This study focuses on formulation of the Augmented Lagrangian and application of the Uzawa's algorithm to solve the homogenization problem of microscopic periodic media as in composites. Unlike in the finite element model, an equally spaced grid system associated with the microstructure domain is used instead of a finite element mesh topology. Moreover, the trigonometric interpolations for the field variables at every grid point help to handle the periodic conditions. The proposed approach is a compromise between Lagrange multiplier and penalty methods, in that it enables exact representation of constraints while using penalty terms to facilitate the iteration procedure. A typical homogenization problem will be solved using this approach. The results show good consistency with those in literatures. Effects of the grid density and the penalty parameter on the convergence have also been investigated.
A simple weak form for contact problems with Coulomb friction
Authors: Tan Tai Nguyen Huynh , Van Anh Le
Published: September 2014

This paper proposes a weak form for the contact problem with Coulomb friction, written as extension of the standard virtual work principle and involving both the displacements and the multipliers defined on the reference contact surface. The mixed relationship is shown to be equivalent to the strong form of the initial/boundary value contact problem, and it can be discretized by means of the finite element method in a simple way. Typical numerical examples are given to assess the efficiency of the formulation in statics and dynamics.
A new view of the Bubnov-Galerkin method in the linearization context
Authors: Dong Anh Nguyen , Elishakoff I.
Published: September 2014

In the study an extension of the Bubnov-Galerkin method in terms of the equivalent linearization method is presented. It is combined with sequential linearization and nonlinear procedure to yield a new method for solving nonlinear equations which can improve the accuracy when the nonlinearity is strong. For illustration the Duffing oscillator is considered to show the effectiveness of the proposed method.
Three-axis piezoresistive accelerometer with adjustable axial resolutions
Authors: Hang Bui Thu , Tan Tran Duc , Trinh Chu Duc
Published: September 2014

A three-axis piezoresistive accelerometer which has adjustable resolutions to three axes was developed using MicroElectroMechanical Systems (MEMS) technology. This sensor made of a heavy proof mass and four long beams is to obtain high resolutions by reducing resonance frequencies. Adjustable resolution with small cross axis sensitivity could be obtained by a three-dimensional sensor structure.
Three-point correlation bounds on the effective bulk modulus of isotropic multicomponent materials
Authors: Chinh Pham Duc , Dong Vu Lam
Published: September 2014

Three-point correlation bounds based on minimum energy principles are constructed to give estimates on the effective elastic bulk modulus of disordered multi-component materials. The constructed trial fields are extensions of Hashin-Shtrikman polarization ones used in our previous approach and lead to tighter bounds. Some examples of applications are presented.
Numerical calculating linear vibrations of third order systems involving fractional operators
Authors: Khang Nguyen Van , Son Tran Dinh , Thuy Bui Thi
Published: September 2014

This paper presents a numerical method for dynamic calculation of third order systems involving fractional operators. Using the Liouville-Rieman's definition of fractional derivatives, a numerical algorithm is developed on base of the well-known Newmark integration method to calculate dynamic response of third order systems. Then, we apply this method to calculate linear vibrations of viscoelastic systems containing fractional derivatives.
A nonlilear controller for ship autopilots
Authors: Tung Le Thanh
Published: September 2014

Conventional ship autopilots are designed based on a linear ship model using pole - placement technique or linear optimal theory.  However, in operation, the ship kinematical parameters can go out the linear  limits. In this paper, a nonlinear optimal control law based on aggregated  variables is presented. The criterion is chosen so that the dynamic  characteristics of object are included. The stability of the closed-loop  system is global according to the Lyapunov stability theory. The control law depends explicitly on ship model parameters, so that it is can be easily to  tune when the parameters change.
Dual approach to averaged values of functions
Authors: Anh N. D.
Published: September 2014

Averaged values play major roles in the study of dynamic processes. The use of those values allows transforming varying processes to some constant characteristics that are much easier to be investigated. In order to extend the use of averaged values one may apply the dual approach which suggests the consideration of two different aspects of a problem in question. This short communication proposes new global and local averaged values functions based on the dual conception.
Attenuation coefficient for surface acoustic waves in fluid region
Authors: Hang Bui Thu , Tung Bui Duc , Dat Nguyen Tien , Trinh Chu Duc
Published: September 2014

In recent years, surface acoustic wave devices used in bio-sensing applications have demonstrated high sensitivity in the detection of fluid properties such as density, viscosity, stream velocity. In this paper, a more effective measurement of the SAWsensorstructure is presented. It is reported that at density of 6 g/cm3, the amplitude of mechanical wave is excited while for electrical signal, attenuation at 3 g/cm3 reaches a peak.In our analysis, single–crystal Aluminium Nitride substrate is used. Several parameters of leaky waves including displacement, decay constant in the liquid media are analyzed.
Simulation and optimization of a silicon-polymer bimorph microgripper
Authors: Phu Phan Huu , Viet Nguyen Ngoc , Ngoc Nguyen Minh , Hung Vu Ngoc , Trinh Chu Duc
Published: September 2014

This paper presents an electro-thermally bimorph microgripper based on silicon-polymer laterally stacked structures and a method to optimized the fabricated device. The actuated displacement is enhanced due to the polymer constraint effect. Both the thermal expansion and apparent Young’s modulus of the constrained polymer blocks are significantly improved, compared with the no constraint one. The device consists of a serpentine-shape deep silicon structure with a thin film aluminum heater on the top and filling polymer in the trenches among the vertical silicon parts. The fabricated bimorph microgripper can operate in four modes and generates a large motion up to 15 μm. The simulated results are met the fabricated measurements. An optimized structure is proposed for decreasing the working temperature, power consumption but increasing the output displacement. The simulated results are showed that the output displacement is increased up to 550% and temperature profile improved considerably. This electro-thermally silicon-polymer opened and closed microgripper can be used in micro-robotics, micro-assembly, minimally invasive surgery, living cells surgery.
Integration of CNTs thin film for sensing and actuating micro structures
Authors: Dau Van Thanh , Tung Bui Thanh , Dao Dzung Viet , Sugiyama Susumu
Published: September 2014

This paper reports the top-down fabrication of CNTs thin film on MEMS structure to develop sensing and actuating micro structures. In particular, this paper review the integration of CNTs film in application of silicon micromirror based on angular vertical comb actuator, development of microstructures with piezoresistive effect and Seebeck effect.
Buckling of double-walled carbon nanotubes
Authors: Elishakoff Isaac , Dujat Kévin , Lemaire Maurice
Published: September 2014

In this note we deal with the approximate solution of the buckling problem of a clamped-free double-walled carbon nanotube. First the finite difference method is utilized to solve this case. Then this approach is verified by solving the buckling problem of a double-walled carbon nanotube that is simply supported at both ends for which the exact solution is available.
Dual approach to averaged values of functions: Advanced formulas
Authors: Anh N. D.
Published: September 2014

Averaged values play major roles in the study of dynamic processes. The use of those values allows transforming varying processes to some constant characteristics that are much easier to be investigated. In order to extend the use of averaged values one may apply the dual approach which suggests a consideration of two different aspects of a problem in question. This short communication proposes new advanced formulas for average values of functions based on the dual conception.
Explicit homogenized equations of the piezoelectricity theory in a two-dimensional domain with a very rough interface of comb-type
Authors: Vinh Pham Chi , Tung Do Xuan
Published: September 2014

The main purpose of this paper is to derive explicit homogenized equations of the linear piezoelectricity in two-dimensional domains separated by a very rough interface of comb-type. In order to do that, first, the basic equations of the theory of piezoelectricity are written down in matrix form. Then, following the techniques presented recently by these authors, the explicit homogenized equation in matrix form and the associated continuity condition, for generally anisotropic piezoelectric materials, are derived. They are then written down in component form for a special case when the solids are made of tetragonal crystals of class 42m. Since the obtained equations are totally explicit, they are significant in use.
Motion of mechanical systems with non-ideal constraints
Authors: Sanh Do , Phong Dinh Van , Khoa Do Dang
Published: September 2014

In the paper a new method to consider a mechanical system with non-ideal constraints is presented. It is proved that a mechanical system subjected to physical non-ideal constraints cannot be determined purely by theoretical analysis because the reaction forces depend on the physical parameters of interactive environment, which are defined only by measurement. The Principle of Compatibility is shown to be an effective tool in combination with experience for investigating such a problem. For illustration the dynamics of a digging machine are investigated.
Generalized pseudo inverse kinematics at singularities for developing five-axes CNC machine tool postprocessor
Authors: My Chu Anh , Hai Vuong Xuan
Published: September 2014

This paper presents an analytical scheme for analyzing the singular configuration problem of general five-axes CNC machine tool. A computational technique based on the generalized pseudo inverse kinematics for finding out feasible solution of the problem is proposed. The technique is then used for developing post processor algorithm of five-axes CNC machine tool. Typical examples of singularity analysis are carried out, and real cutting parts are implemented for verifying the research result.
Monitoring a sudden crack of beam-like bridge during earthquake excitation
Authors: Khoa Nguyen Viet
Published: September 2014

This paper presents a wavelet spectrum technique for monitoring a sudden crack of a beam-like bridge structure during earthquake excitation. When there is a sudden crack caused by earthquake excitation the stiffness of the structure is changed leading to a sudden change in natural frequencies during vibration. It is difficult to monitor this sudden change in the frequency using conventional approaches such as Fourier transform because in Fourier transform the time information is lost so that it is impossible to analyse short time events. To overcome this disadvantage, wavelet spectrum, a time-frequency analysis, is used for monitoring a sudden change in frequency duringearthquake excitation for crack detection. In this study, a model of 3D crack is applied. The derivation of the stiffness matrix of a 3D cracked beam element with rectangular section adopted from fracture mechanics is presented. Numerical results showed that the sudden occurrence of the crack during earthquake excitation can be detected by the sudden change in frequency using wavelet power spectrum. When the crack depth increases, the instantaneous frequency (IF) of the structure is decreased.
Change in mode shape nodes of multiple cracked bar: II. The numerical analysis
Authors: Khiem N. T. , Toan L. K. , Khue N. T. L.
Published: September 2014

In this paper it is numerically analyzed the change in position of mode shape nodes induced by multiple cracks in bar that has been theoretically investigated in previous paper [1] of the authors. The focus is to analyze thoroughly dislocation of node located intermediately between two cracks in dependence upon the crack parameters without assumption on the smallness of crack.
Determination of mode shapes of a multiple cracked beam element and its application for free vibration analysis of a multi-span continuous beam
Authors: Lien Tran Van , Hao Trinh Anh
Published: September 2014

This article presents some results on the determination of the vibration shape function of a multiple cracked elastic beam element, which is modeled as an assembly of intact sub-segments connected by massless rotational springs. Algorithms and computer programs to analyze changes of natural mode shapes of multiple cracked beams have been carried out. Numerical analysis of natural mode shapes of cracked simple support beams using the obtained expression shows a good agreement in comparison with the well-known analytical methods. The methodology approach and results presented in this article are new and basis for building an efficient method to identify cracks in beam structures using wavelet analysis of mode shapes.
Free vibration of thick composite plates on non-homogeneous elastic foundations by dynamic stiffness method
Authors: Cuong Nguyen Manh , Thinh Tran Ich , Hien Ta Thi , Ninh Dinh Gia
Published: September 2014

This research presents a new model for vibration analysis of thick laminated plates on a non-homogeneous elastic foundation by the Dynamic Stiffness Method(DSM). The non-homogeneous foundation consists of multi-segment Winkler-type and Pasternak-type elastic foundation. The Dynamic Stiffness Matrices using the First ShearDeformation Theory (FSDT) are constructed for cross-ply thick composite plates. A computer program is written using the present formulation for calculating natural frequencies and harmonic response of composite plates subjected to various types of boundary conditions. Numerical results are validated by comparison with available results in the literature and with Finite Element Method (FEM). Different test cases make evidence the advantages of the present model: higher precision, less data storage, less computing time and studied frequency range extended.
An effective algorithm for reliability-based optimization of stiffened Mindlin plate
Authors: Trung Nguyen Thoi , Thang Bui Xuan , Vinh Ho Huu , Thuan Lam Phat , Phong Ngo Thanh
Published: September 2014

Nowadays, stiffened plates have been widely used in many branches of structural engineering such as aircraft, ships, bridges, buildings etc... In comparison with common bending plate structures, stiffened plates not only have larger bending stiffness but also use less amount of material. Hence, it usually has higher economic efficiency. However, to obtain high effectiveness in solving the design problems of the stiffened plate, the reliability-based optimization problems need to be established together with the ordinary numerical computing methods. Therefore, the paper presents an approach to establish and solve the reliability-based optimization problem for the stiffened Mindlin plate. To analyze the behavior of Mindlin plate, we use the recently proposed CS-DSG3 element. The random variables are chosen to be elastic modulus, density of mass and external force. The design variables are the thickness, the width and the height of the stiffened plate. The objective function can be the strain energy or the mass of the structure and subjected to the constraints of displacement or vibration frequency. The reliability-based optimization algorithm used in this paper is a three-step closed loop: 1) Estimating the random variables by the Reliability Index (RI) method; 2) Solving the optimization problem using Sequential Quadratic Programming (SQP) method; 3) Checking and estimating the reliability by the first-order reliability method (FORM) in which the limit state function is the limit of displacement or vibration frequency of the structure.
On the convergence of a coupling successive approximation method for solving Duffing equation
Authors: Bich Dao Huy , Bich Nguyen Dang
Published: September 2014

General Duffing equations occur in many problems of Mechanics and Dynamics. These equations include nonlinear terms of second and third order, their coefficients are finite but not small parameters. For finding analytical approximate solutions of the general Duffing equation the coupling successive approximation method (CSAM) has been proposed by the authors.In the present paper the convergence of mentioned method is proven and a condition relating coefficients of Duffing equation to provide the convergence procedure is formulated. Emphasize that the assumption of small parameters is not used in the proving.Some examples are presented to illustrate the proposed method, particularly exact solutions of some problems are compared with analytical approximate ones found by CSAM.
Gravity-induced shear force in reinforced concrete walls above transfer structures
Authors: Tang Tim On , Su Ray Kai Leung
Published: September 2014

In this study, the gravity loads in reinforced concrete shear walls supported on transfer structures are investigated. Emphasis is placed on the shear-stress concentration effects on the supported shear walls owing to the distortion of the transfer structure. A simplified model is proposed to illustrate the fundamental physical interactions. Finite-element analysis is also conducted to study the influences of the symmetric and asymmetric shear-wall arrangements, positioning of supporting columns and span-to-depth ratio of the transfer structure. Non-linear behaviours encompassing the use of yielded stiffness at ultimate limit state, sequential construction and the creep of reinforced concrete under gravity loads are addressed. Various effects of modelling assumptions and simplifications on the stress redistribution of the transfer structure are investigated. Remedial measures are proposed, such as increasing the depth of the transfer girders using late-cast slabs, segmented upper shear walls and concrete of higher grade for critical regions.
Understanding protected area resilience: a multi‐scale, social‐ecological approach
Authors: Cumming Graeme S. , Allen Craig R. , Ban Natalie C. , Biggs Duan , Biggs Harry C. , Cumming David H. M. , De Vos Alta , Epstein Graham , Etienne Michel , Maciejewski Kristine , Mathevet Raphaël , Moore Christine , Nenadovic Mateja , Schoon Michael
Published: September 2014

Protected areas (PAs) remain central to the conservation of biodiversity. Classical PAs were conceived as areas that would be set aside to maintain a natural state with minimal human influence. However, global environmental change and growing cross‐scale anthropogenic influences mean that PAs can no longer be thought of as ecological islands that function independently of the broader social‐ecological system in which they are located. For PAs to be resilient (and to contribute to broader social‐ecological resilience), they must be able to adapt to changing social and ecological conditions over time in a way that supports the long‐term persistence of populations, communities, and ecosystems of conservation concern. We extend Ostrom's social‐ecological systems framework to consider the long‐term persistence of PAs, as a form of land use embedded in social‐ecological systems, with important cross‐scale feedbacks. Most notably, we highlight the cross‐scale influences and feedbacks on PAs that exist from the local to the global scale, contextualizing PAs within multi‐scale social‐ecological functional landscapes. Such functional landscapes are integral to understand and manage individual PAs for long‐term sustainability. We illustrate our conceptual contribution with three case studies that highlight cross‐scale feedbacks and social‐ecological interactions in the functioning of PAs and in relation to regional resilience. Our analysis suggests that while ecological, economic, and social processes are often directly relevant to PAs at finer scales, at broader scales, the dominant processes that shape and alter PA resilience are primarily social and economic.
Feasibility of Lowering Soybean Planting Density without Compromising Nitrogen Fixation and Yield
Authors: Javier de Luca Marcos , Nogueira Marco Antonio , Hungria Mariangela
Published: September 2014

Adjusting soybean [Glycine max (L.) Merrill] density can be critical to reduce inter‐plant competition for water, nutrients, and sunlight, and to increase intercepted radiation, photosynthesis, and biomass production. The objective of this study was to evaluate the effects of soybean‐population density on soybean nodulation, plant nutrient status, yield, and grain quality. Three field experiments were performed in southern Brazil with soybean cultivar BRS 284, of indeterminate growth type and maturity group 6.6, at 80,000 and 320,000 plants ha−1. For N supply plants were dependent either largely on biological fixation of atmospheric N—with a naturalized population of Bradyrhizobium or inoculated with Bradyrhizobium japonicum strain CNPSo 2050—or largely on N fertilizer—200 kg N ha−1, split‐applied at sowing and R1 growth stage. The lower plant density resulted in increased nodulation parameters (number and mass), but plant nutritional status—evaluated by the diagnosis and recommendation integrated system (DRIS) method—in general was not affected. Seed oil content increased by 3.4%, but protein decreased by 4.5% at the lower plant density. The N source affected nodulation, but not nutritional status or grain yield. Although plant density was reduced by 75%, yield decreased by 16% during only one of the three cropping seasons. These results indicate a high plasticity of soybean to adapt photosynthesis and N fixation to different plant densities. Furthermore, planting at the lower density has the advantages of lower input costs and less susceptibility to environmental and plant nutritional stresses.
The electric field induced by transcranial magnetic stimulation: A comparison between analytic and fem solutions
Authors: Porzig Konstantin , Brauer Hartmut , Toepfer Hannes
Published: September 2014

The induced electric field profiles in a homogeneous isotropic sphere, were
calculated and compared between an analytic and a finite-element method in
the framework of transcranial magnetic stimulation (TMS). This model can
also be applied for concentric spheres in the framework of magnetic
induction tomography (MIT), non destructive testing (NDT) or to calculate
the lead field in magnetoencephalography (MEG). The calculations were
performed using Eaton?s method as well as the finite-element program Comsol
Multiphysics 4.2a (COMSOL Inc., Burlington, USA). A circular- and a
figure-of-8 coil were used to operate as the sources of excitation. In our
study the spherical volume conductor represents the human head consisting of
grey matter. In order to quantify the differences between both methods an
intense parameter study was performed. A comparison between both methods
show a higher conformity than reported in previous studies. Regarding
Eaton?s method, the influence of the maximum order of approximation L and
the number of elements per winding K was investigated. The maximum relative
difference was approximately 0.3% for L = 20 and K > 16. Furthermore the
relative efficiency of the algorithm was calculated to save computational
time. With the presented results it is possible to use Eaton?s method
efficiently to compute the induced electric field profiles very quickly for
example while searching for specific coil arrangements around the humans
head, as in the case of deep brain transcranial magnetic stimulation (dTMS).
Acute Toxic Effects of Cadmium in Larvae of the Green Toad, Pseudepidalea Variabilis (Pallas, 1769) (Amphibia: Anura)
Authors: Gürkan Mert , Çetin Ayşe , Hayretdaĝ Sibel
Published: September 2014

The environmental impact of cadmium use and its accumulation in nature have increased to alarming levels. This study aimed to morphologically and histologically investigate the acute toxic effects of cadmium on green toad, Pseudepidalea variabilis (Pallas, 1769) larvae. Embryos were obtained from specimens collected in amplexus from nature and kept under laboratory conditions until stage 26, when they were exposed to cadmium (0, 1, 5, 10, 25, and 50 Lig L-1) for 96 h. The LC10 LC50, and LC90 values of cadmium were calculated to be 26.98, 35.35, and 46.31 Lig L-1, respectively. Our results showed that cadmium had a negative effect on the body size of P. variabilis larvae (over 1 ng L-1). Histological examination detected a fusion of gill lamellae, liver haemorrhage, oedema in the abdominal cavity, and deformations of pronephric tubules (over 10 ng L-1). Our findings suggest that the green toad was sensitive to the cadmium treatment, with LC50 values lower than those reported by other studies. Thus, this species could be considered a reliable indicator species of environmental stress in aquatic ecosystem.
MAMLD1 Gene Mutation in the Incidence of Hypospadias in the Chinese Population
Authors: Zhuang Likai , Bai Ming , Zhou Wei , Yu Yongguo , Wang Jian , Fu Qihua , Sun Jie
Published: September 2014

Background: This study aimed to investigate the significance of MAMLD1 mutations in the incidence of hypospa-dias in a Chinese population.

Methods: The experimental group consisted of 150 domestic children with hypospadias, aged 0.5 to six years and living in different provinces. A total of 120 normal children, aged two to six years, served as the control group. DNA was extracted for the direct sequencing of MAMLD1 genes.

Results: Twelve cases (8.0%) of the missense mutation p.N589S were found in the experimental group, whereas four cases (3.0%) of the same mutation were found in the control group. No significant difference was observed in the mutation rate between the two groups (P>0.05). Four cases (2.7%) had a new missense mutation p.P567S in the experimental group, and three cases (2.5%) possessed the same mutation in the control group. No significant difference was observed between the two groups (P>0.05).

Conclusions: In this study, the importance of repeated experiments in mutation-related studies was confirmed, which revealed the difference in predisposing genes among different populations. Although the mutation of the MAMLD1 gene had no apparent connection with the incidence of hypospadias in a Chinese population, a new mutation site of the MAMLD1 gene was discovered, which could provide new research topics for future studies.
PAH and QDPR Deficiency Associated Mutations in the Novosibirsk Region of the Russian Federation: Correlation of Mutation Type with Disease Manifestation and Severity
Authors: Baturina Olga A. , Tupikin Alexey E. , Lukjanova Tatyana V. , Sosnitskaya Svetlana V. , Morozov Igor V.
Published: September 2014

Background: Efficient treatment of inherited hyperphenyl-alaninemia requires exact identification of mutations defining the trait. Such knowledge is important both for effective individual therapy and understanding of the genetic history and evolution of regional populations.

Methods: DNA sequencing of amplified genome regions was used to identify mutations.

Results: Hyperphenylalaninemia-associated mutations in the phenylalanine hydroxylase locus were identified for 76 unrelated patients from the Novosibirsk region, Russia and for their family members. Twenty-one mutation types were identified, most of them rare and one (IVS2+1delG) not previously described. Common for European populations, the mutation p.R408W appeared to be the most frequent, with allele frequency 63.33%. We also looked for mutations in the quinoid dihydropteridine reductase locus in some patients. For 36 unrelated children PKU patients with known blood phenylalanine levels, we tried to find correlations between this level and the genotype.

Conclusions: Comparative analysis revealed correlations between blood phenylalanine levels and genotypes. The spectrum of phenylalanine hydroxylase mutations in the Novosibirsk region population appeared to be rather complex, probably as a result of mixed ethnic composition, formed by several multidirectional migration flows.