Stability of asymmetric tetraquarks in the minimal-path linear potential

The linear potential binding a quark and an antiquark in mesons is generalized to baryons and multiquark configurations as the minimal length of flux tubes neutralizing the color, in units of the string tension. For tetraquark systems, i.e., two quarks and two antiquarks, this involves the two possible quark--antiquark pairings, and the Steiner tree linking the quarks to the antiquarks. A novel inequality for this potential demonstrates rigorously that within this model the tetraquark is stable in the limit of large quark-to-antiquark mass ratio.Comment: 8 pages, 6 figures, pdflate

CPG-Based Autonomous Swimming Control for Multi-Tasks of a Biomimetic Robotic Fish

This work emphasizes the artificial intelligent control of the developed biomimetic robotic fish (i-RoF) based on sensory feedback Central Pattern Generator (CPG) approach. In order to obtain rhythmic, robust and adaptable closed loop control performance, a novel control mechanism, composed of two subsystems; as a biological based CPG network and a Fuzzy Logic controller, is proposed. The CPG network behaves as an artificial spinal cord, inspired by Lampreys. It is constructed as unidirectional chained network with Sensory Neurons (SNs) which can perceive the external stimulus. The Fuzzy Logic control structure is also designed as a decision-making mechanism and a Finite State Machine (FSM) algorithm is proposed to perform the given missions autonomously. In the experimental studies, different scenarios are created for both situations as autonomous swimming and encountering obstacles while taking on a primary task, which is determined with yaw control. Autonomous swimming ability is performed in the real pool environment with proposed scenarios that are likely to be encountered in a real environment. It is observed that autonomous swimming performance is excellent and yaw control is quite good even in the presence of obstacles. It is also proved that the escape performance of the robot is very fast

FSI Analysisof Carangiform Three Dimensional Multi-Link Biomimetic Robotic Fish

Bu çalışmada akışkan içerisinde hareket eden carangiform yüzüş moduna sahip üçboyutlu ve çokeklemlibir robot balık modeline etki eden hız, basınç ve girdap değerlerinin bulunması amaçlanmıştır. Bu amaç doğrultusunda HAD (Hesaplamalı akışkanlar dinamiği) yazılımlarından biri olan Ansys paket programı ileüç boyutlu robot balığın hidrodinamik analizi gerçekleştirilmiştir. Bu analizde FSI (akışkan-yapı analizi) yöntemi kullanılmıştır. Analiz sırasında kullanılan üç boyutlu ve çok eklemli robot balık modelinin SolidWorks paket programında tasarımı gerçekleştirilmiştir. Analizin ilk aşamasında robot balık sabit tutularak sınırları belirli bir havuz içerisinde akışkan olarak seçilen suya farklı hız değerleri uygulanmıştır ve bu değerler için balığa etki eden hız, basınç ve girdap değerleri incelenmiştir. Analizin ikinci aşamasında ise durgun akışkan ortamında robot balığın farklı iki yüzüş modeline ait (düz yüzüş ve dönüş)açı değerleri eklemlere uygulanarak balığın hareketleri sağlanmıştır. Buçalışma ile carangiform üç boyutlu ve çok eklemli biomimetik birrobot balığın deneysel gerçeklemesinden önce Ansys ortamına yansıtılmasıyla sınırları belirli bir havuz içerisinde hız, basınç ve girdap değerlerinin bulunması hedeflenmiştir.In this study, it is proposed to obtain velocity, pressure and vorticity values affected to three dimensional and multi-link robotic fish model. The hydrodynamic analysis of three dimensional robotic fish with Ansys software, one of the CFD (computational fluid dynamics) softwares, is carried out. In this analysis, the FSI (fluid-structure analysis) method is used. Design of three dimensional and multi-link robotic fish model is realized in SolidWorks package program during the analysis. In the first stage of the analysis, the robot fish is kept constant in the pool with defined boundaries and different values are applied to water chosen as fluid.Velocity, pressure and vorticity values are investigated for different velocity of the fluid. In the second stage of the analysis, the movements of the robotic fish are provided by applying angles obtained from two different swimming models (forward and turning swim) of the robotic fish to joints in static fluid environment.With this study, velocity, pressure and vorticity values affected on carangiform three dimensional and the multi-linkbiomimetic robotic fish are proposed to obtain in the ANSYS environment before the experimental realization of the robotic fish

FSI Analysisof Carangiform Three Dimensional Multi-Link Biomimetic Robotic Fish

Bu çalışmada akışkan içerisinde hareket eden carangiform yüzüş moduna sahip üçboyutlu ve çokeklemlibir robot balık modeline etki eden hız, basınç ve girdap değerlerinin bulunması amaçlanmıştır. Bu amaç doğrultusunda HAD (Hesaplamalı akışkanlar dinamiği) yazılımlarından biri olan Ansys paket programı ileüç boyutlu robot balığın hidrodinamik analizi gerçekleştirilmiştir. Bu analizde FSI (akışkan-yapı analizi) yöntemi kullanılmıştır. Analiz sırasında kullanılan üç boyutlu ve çok eklemli robot balık modelinin SolidWorks paket programında tasarımı gerçekleştirilmiştir. Analizin ilk aşamasında robot balık sabit tutularak sınırları belirli bir havuz içerisinde akışkan olarak seçilen suya farklı hız değerleri uygulanmıştır ve bu değerler için balığa etki eden hız, basınç ve girdap değerleri incelenmiştir. Analizin ikinci aşamasında ise durgun akışkan ortamında robot balığın farklı iki yüzüş modeline ait (düz yüzüş ve dönüş)açı değerleri eklemlere uygulanarak balığın hareketleri sağlanmıştır. Buçalışma ile carangiform üç boyutlu ve çok eklemli biomimetik birrobot balığın deneysel gerçeklemesinden önce Ansys ortamına yansıtılmasıyla sınırları belirli bir havuz içerisinde hız, basınç ve girdap değerlerinin bulunması hedeflenmiştir.In this study, it is proposed to obtain velocity, pressure and vorticity values affected to three dimensional and multi-link robotic fish model. The hydrodynamic analysis of three dimensional robotic fish with Ansys software, one of the CFD (computational fluid dynamics) softwares, is carried out. In this analysis, the FSI (fluid-structure analysis) method is used. Design of three dimensional and multi-link robotic fish model is realized in SolidWorks package program during the analysis. In the first stage of the analysis, the robot fish is kept constant in the pool with defined boundaries and different values are applied to water chosen as fluid.Velocity, pressure and vorticity values are investigated for different velocity of the fluid. In the second stage of the analysis, the movements of the robotic fish are provided by applying angles obtained from two different swimming models (forward and turning swim) of the robotic fish to joints in static fluid environment.With this study, velocity, pressure and vorticity values affected on carangiform three dimensional and the multi-linkbiomimetic robotic fish are proposed to obtain in the ANSYS environment before the experimental realization of the robotic fish

Forage Crops Genetic Resources of Turkey

Çok çeşitli nedenlerle erozyona uğrayan ve kaybolma tehlikesi bulunan yem bitkisi cins ve türlerinin toplanması, üretilmesi, karakterizasyonun yapılıp değerlendirilmesi ve uzun süreli muhafaza altına alınıp araştırıcıların hizmetine sunulması önem arz etmektedir. Doğal floranın korunması, botanik kompozisyonun bozulmaması ve gelecek kuşaklara yem bitkisi bakımından zengin bir materyal kaynağının bırakılması amacıyla yapılan çalışmalar günden güne önemli ivme kazanmıştır. Ülkemizde genetik kaynakların kullanılması konusunda önemli aşamalar kaydedilmiş, geliştirilen çeşitlerin ekonomiye kazandırılması ile önemli bir katkı sağlanıp ülke ekonomisine katma değer yaratılmıştır. Yeni teknolojik gelişmeler ile daha ayrıntılı çalışmalar yapılarak önümüzdeki yıllarda yüzyüze geleceğimiz iklim değişikliklerine karşı daha dayanıklı materyallerin bitki genetik kaynakları kullanılarak geliştirilebileceği düşünülmektedir.Studies on collection, regeneration and conservation of forage crops genetic resources that have been exposed to erosion pressure and in danger of extintion due to various reasons has taken important momentum in terms of maintaining plant researchers with this material and of inheriting rich natural resources to next generations. Important developments on utilization of plant genetic resources have also been achieved. Registred varities have been put into national economy getting added values. It is thought that due to new technologic advancements further detailed studies to be carried out could faciliate more resistant material adaptable to climatic conditions facing us using plant genetic resources

Locomotion Control of A Biomimetic Robotic Fish Based on Closed Loop Sensory Feedback CPG Model

This paper presents mechatronic design and hierarchical locomotion control of a biomimetic robotic fish for three-dimensional swimming modes. Inspired by biological features of Lamprey, a closed loop sensory feedback Central Pattern Generator (CPG) model is adapted to hierarchical control mechanism in order to provide robust and effective biomimetic control structure. A sensory feedback mechanism plays an important role to react external stimuli from environment. In addition, a closed loop fuzzy logic control structure is developed as a brain model to decide adaptive swimming modes according to sensory information. In order to provide three-dimensional motion abilities, the Centre of Gravity (CoG) control mechanism is designed and controlled by a back-forth proportional control structure. Experimental results are obtained to prove the CPG-based closed loop sensory feedback control structure with the developed robotic fish prototype

Locomotion control of a biomimetic robotic fish based on closed loop sensory feedback CPG model

This paper presents mechatronic design and hierarchical locomotion control of a biomimetic robotic fish for three-dimensional swimming modes. Inspired by biological features of Lamprey, a closed loop sensory feedback Central Pattern Generator (CPG) model is adapted to hierarchical control mechanism in order to provide robust and effective biomimetic control structure. A sensory feedback mechanism plays an important role to react external stimuli from environment. In addition, a closed loop fuzzy logic control structure is developed as a brain model to decide adaptive swimming modes according to sensory information. In order to provide three-dimensional motion abilities, the Centre of Gravity (CoG) control mechanism is designed and controlled by a back-forth proportional control structure. Experimental results are obtained to prove the CPG-based closed loop sensory feedback control structure with the developed robotic fish prototype

Mechatronic Design and Manufacturing of the Intelligent Robotic Fish for Bio-Inspired Swimming Modes

This paper presents mechatronic design and manufacturing of a biomimetic Carangiform-type autonomous robotic fish prototype (i-RoF) with two-link propulsive tail mechanism. For the design procedure, a multi-link biomimetic approach, which uses the physical characteristics of a real carp fish as its size and structure, is adapted. Appropriate body rate is determined according to swimming modes and tail oscillations of the carp. The prototype is composed of three main parts: an anterior rigid body, two-link propulsive tail mechanism, and flexible caudal fin. Prototype parts are produced with 3D-printing technology. In order to mimic fish-like robust swimming gaits, a biomimetic locomotion control structure based on Central Pattern Generator (CPG) is proposed. The designed unidirectional chained CPG network is inspired by the neural spinal cord of Lamprey, and it generates stable rhythmic oscillatory patterns. Also, a Center of Gravity (CoG) control mechanism is designed and located in the anterior rigid body to ensure three-dimensional swimming ability. With the help of this design, the characteristics of the robotic fish are performed with forward, turning, up-down and autonomous swimming motions in the experimental pool. Maximum forward speed of the robotic fish can reach 0.8516 BLs-1 and excellent three-dimensional swimming performance is obtained

Three-Dimensional Modeling of a Robotic Fish Based on Real Carp Locomotion

This work focuses on developing a complete non-linear dynamic model comprising entirely kinematic and hydrodynamic effects of Carangiform locomotion based on the Lagrange approach by adapting the parameters and behaviors of a real carp. In order to imitate biological features, swimming patterns of a real carp for forward, turning and up-down motions are analyzed by using the Kineova 8.20 software. The proportional optimum link lengths according to actual size, swimming speed, flapping frequency, proportional physical parameters and different swimming motions of the real carp are investigated with the designed robotic fish model. Three-dimensional (3D) locomotion is evaluated by tracking two trajectories in a MATLAB environment. A Reaching Law Control (RLC) approach for inner loop (Euler angles-speed control) and a guidance system for the outer loop (orientation control) are proposed to provide an effective closed-loop control performance. In order to illustrate the 3D performance of the proposed closed loop control system in a virtual reality platform, the designed robotic fish model is also implemented using the Virtual Reality Modeling Language (VRML). Simulation and experimental analysis show that the proposed model gives us significant key solutions to design a fish-like robotic prototype