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Computation of Impact Factor of High-Speed Railway Bridge by KTX Train Riding Test  [PDF]
Hyejin Yoon, Won Jong Chin, Jae Yoon Kang, Jongwon Kwark, Eui-Seung Hwang
Engineering (ENG) , 2013, DOI: 10.4236/eng.2013.59090

The design live load of railway is divided into common railway and high-speed railway separately inKorea. Accordingly, the Korean design specification of railway specifies the impact factor for common railway and high-speed railway respectively. The impact factor for high-speed railway is based on Eurocode. Since the impact factor criteria inKoreawere established by adopting those of the Eurocode and without dedicated investigation relying on research results reflecting the domestic circumstances, thorough examination should be implemented on these criteria. Therefore the evaluation of impact factor based on field tests is required. Both dynamic and static vertical displacements are necessary to compute the impact factor. The dynamic response can be obtained from the measurement of deflection of the bridge slab crossed by the firstKoreahigh-speed train (KTX, Korea Train eXpress) running at high-speed. The main difficulties encountered are in obtaining static response because static response corresponds to the response of the bridge when the train remains immobile on the bridge or crosses the bridge at speed slower than5 km/hr. This study introduces the static response derived by applying the moving average method on the dynamic response signal. To that goal, field measurements was conducted under train speeds of5 km/hr and ranging from100 km/hr to300 km/hr on Yeonjae Bridge located in the trial section of the Gyeonbu High-Speed Railway Line before its opening. The validity of the application of the moving average method is verified from comparison of measured static response and derived static response by moving average method. Moreover, evaluation is conducted on the impact factor computed for a bridge crossed by the KTX train running at operational speed.

Comparison of computation methods for stress response of bridges under train load

- , 2017, DOI: 10.3969/j.issn.1001-0505.2017.03.027
Abstract: 为有效分析列车引起的桥梁应力响应,对车桥耦合动力分析法、静力影响线法及移动集中力法3种列车作用下的桥梁应力响应计算方法进行了深入的比较研究.采用3种方法对2座铁路典型混凝土简支T梁和下承式钢桁梁桥进行应力响应分析, 基于桥梁现场实测数据对比分析了不同方法的计算结果,研究了列车速度和桥梁横向振动对应力结果的影响.结果表明:车速对桥梁应力响应有显著的影响,共振发生时3种方法的计算结果相差较大,消振条件下三者区别减小;由列车水平方向作用力引起的桥梁或构件横向振动对应力响应的贡献不容忽视;车桥耦合动力分析法能够更为真实地反映桥梁构件的动应力历程,在高速、桥梁横向刚度较低或列车局部加载的情况下尤其具有计算精度优势.研究结果可为3种不同计算方法的工程应用提供参考.
To effectively analyze the train-induced stress responses of bridges, a comparative study on three computation methods for the stress responses of bridges under train loads, namely, the train-bridge coupled vibration analysis method, the static influence line method, and the moving concentrated load method is performed. The stress responses of two typical railway bridges, a concrete simply-supported T beam bridge and a steel through truss girder bridge, are analyzed through the three methods. The computation results from various methods are compared and analyzed by using the data measured at the bridge sites. The influences of the train speed and the bridge lateral vibration on the stress results are investigated. The results show that the train speed significantly affects the bridge stress responses. Considerable differences are found in the computation results obtained from the three methods when the vibration resonance occurs, while the differences are reduced under the condition of the vibration cancellation. The contributions of the lateral vibrations of the bridges or the components induced by the horizontal train loading to the stress responses cannot be neglected. The train-bridge coupled vibration analysis method can more truly reflect the dynamic stress histories, and especially has the advantages of calculation accuracy in the cases of high speed, low lateral bridge stiffness, or local train loading. The results can provide references for the engineering applications of three different computation methods
Amino acid sequence determination and chemical synthesis of CllErg1 (gamma-KTx1.5), a K+ channel blocker peptide isolated from the scorpion Centruroides limpidus limpidus
Coronas, Fredy I.;Balderas, Cipriano;Pardo-López, Liliana;Possani, Lourival D.;Gurrola, Georgina B.;
Journal of the Brazilian Chemical Society , 2005, DOI: 10.1590/S0103-50532005000300014
Abstract: a novel toxin named cllerg1 (systematic nomenclature g-ktx1.5) was purified from the venom of the scorpion centruroides limpidus limpidus and its amino acid sequence was determined. it has 42 amino-acid residues cross-linked by four disulfide bridges and blocks specifically a potassium channel of the family ether-a-go-go (erg). the full peptide was chemically synthesized and properly folded, showing that it blocks the human erg-channels (herg) with identical affinity to that of the native peptide. synthetic cllerg1 can be produced in quantities enough to compensate its low concentration in the natural venom. it paves the way to conduct studies aimed at the identification of the structural motifs of herg critical for proper channel function. additionally, another analogous peptide cllerg2 (systematic name g-ktx4.1) was purified and had its full amino acid sequence determined. it contained 43 amino acid residues, maintained closely packed by four disulfide bridges.
Amino Acid Sequence Determination and Chemical Synthesis of CllErg1 (γ-KTx1.5), a K+ Channel Blocker Peptide Isolated from the Scorpion Centruroides limpidus limpidus  [cached]
Fredy I. Coronas,Cipriano Balderas,Liliana Pardo López,Lourival D. Possani
Revista de la Sociedad Química de México , 2005,
Abstract: A novel toxin named CllErg1 (systematic nomenclature γ-KTx1.5) was purified from the venom of the scorpion Centruroides limpidus limpidus and its amino acid sequence was determined. It has 42 amino-acid residues cross-linked by four disulfide bridges and blocks specifically a potassium channel of the family ether-a-go-go (ERG). The full peptide was chemically synthesized and properly folded, showing that it blocks the human ERG-channels (HERG) with identical affinity to that of the native peptide. Synthetic CllErg1 can be produced in quantities enough to compensate its low concentration in the natural venom. It paves the way to conduct studies aimed at the identification of the structural motifs of HERG critical for proper channel function. Additionally, another analogous peptide CllErg2 (systematic name γ-KTx4.1) was purified and had its full amino acid sequence determined. It contained 43 amino acid residues, maintained closely packed by four disulfide bridges.
Train-bridge Coupled Vibration Analysis of a Large-span Simply-supported Steel-truss Railway Bridge

- , 2017, DOI: 10.3969/j.issn.1000-0844.2017.05.0820
Abstract: 桥梁作为线路工程中不可或缺的重要枢纽,对列车通过桥梁时,桥梁和车辆之间相互作用的问题迫切需要做出解答,特别是针对铁路钢桁梁,并考虑大跨度简支特性的车-桥耦合振动问题研究更具有一定的理论与实际意义。以黄韩侯铁路新黄河特大桥156 m简支钢桁梁桥作为工程背景,建立车辆动力模型、桥梁有限元模型并考虑轮轨关系,以蛇形运动和轨道不平顺作为系统的自激激励源,利用大型有限元软件ANSYS以及UM(Universal Mechanism)动力学分析软件联合进行仿真分析,实现单个机车、编组客车和编组货车以设计时速通过桥梁时对大跨度简支钢桁梁桥车-桥耦合振动的研究。经过计算分析得出:大跨度钢桁梁桥的横向刚度相对较小;不同编组情况以设计时速通过桥梁时,车辆和桥梁的各项动力响应参数均在规范允许的范围之内;编组货车通过桥梁时,桥梁跨中横向、竖向加速度较之其他编组情况要大。
Over recent years, high-speed and heavy-load railways have developed in China. For a railway line, bridges are very important hubs along the line. Studies on the interaction between trains and bridges are very important for safe railway operations, especially for problems regarding the train-bridge coupled vibration of simply-supported steel-truss railway bridges, which have been widely used in recent years. In this paper, a 156-m-long simply-supported steel-truss bridge of the Huang Han-hou New Yellow River railway was studied. Numerical simulation using ANSYS and UM software is used together to study the train-bridge coupled vibration problems when a single locomotive, marshaling passenger coach, and freight coach pass the bridge. The results show that the lateral stiffness of the large-span steel-truss bridge is relatively small. The dynamic response parameters of the train and bridge all fell within the allowable limits when the different marshaling passenger coaches pass the bridge with the design speed. Compared with conditions of a single locomotive and marshaling passenger coach, the lateral and vertical accelerations of the bridge are obviously greater when the marshaling freight coaches pass.
An Inertial Reaction to Cosmological Accelerations  [PDF]
Scott Funkhouser
Physics , 2003,
Abstract: Mach's "fixed stars" are actually not fixed at all. The distant clusters of galaxies are not only receding from each observer but they are also accelerating since the rate of cosmological expansion is not constant. If the distant cosmic masses in someway constitute the frame of inertial reference then an additional force should be generated among local bodies in reaction to the apparent cosmological accelerations of the distant galaxies.
Vibration Analysis of Bridges Excited by Uncertain Train Moving Loads

- , 2019,
Abstract: 通过引入区间过程模型,提出了一种针对受列车移动载荷激励的桥梁的不确定振动分析方法,可以得到列车经过时桥梁振动挠度响应的上下边界曲线。将单节列车用两个等间隔轮载荷的子系统来模拟,一个包含前轮部分,另一个包含后轮部分。将桥梁简化为简支梁模型,用区间过程来描述列车对桥梁的不确定性移动载荷激励。基于区间过程模型和模态叠加理论,得到桥梁挠度响应的中值函数和半径函数,从而得到挠度响应的上下边界函数。通过数值算例说明本文方法的有效性。
By introducing the interval process model, this paper proposes an uncertain vibration analysis method for bridges subjected to train moving loads to obtain the upper and lower boundary curves of vibration deflection response of the bridges. Each train is modeled as two subsystems of wheel loads of constant intervals, one containing the front wheel section and the other consisting of the rear wheel section. The bridge is simplified to a simply supported beam model, and the interval process model is used to describe the uncertainty of the moving load flow excitation of the train applied to the bridge. By combining the interval process model and the modal superposition vibration analysis theory, the middle function and radius function of deflection response of the bridge can be obtained, based on which the upper and lower boundary functions of the deflection response can be obtained. Finally, the effectiveness of the proposed method is illustrated by investigating several numerical examples
Birth accelerations of neutron stars  [PDF]
Ricardo Heras
Physics , 2013, DOI: 10.1017/S1743921312024271
Abstract: We suggest that neutron stars experienced at birth three related physical changes, which may originate in magneto-rotational instabilities: (i) an increase in period from the initial value P_0 to the current value P_s, implying a change of rotational energy \Delta E_rot; (ii) an exponential decay of its magnetic field from the initial value B_0 to the current surface value B_s, implying a change of radiative energy \Delta E_rad; and (iii) an increase of space velocity from the initial value v_0 to the current value v, implying a change of kinetic energy \Delta E_kin. These changes are assumed to be connected by \Delta E_rad + \Delta E_kin =\Delta E_rot. This means that the radiation loss and increase of kinetic energy are both at the expense of a rotational energy loss. It is shown that this energy conversion occurs during times of order of 10^(-4) s if the neutron stars are born with magnetic fields in the range of 10^(15)-10^(16) G and initial periods in range 1-20 ms. It is shown that the birth accelerations of neutron stars are of the order of 10^(8) g.
Measurement of particle and bubble accelerations in turbulence  [PDF]
Romain Volk,Nicolas Mordant,Gautier Verhille,Jean-Fran?ois Pinton
Physics , 2007, DOI: 10.1209/0295-5075/81/34002
Abstract: We use an extended laser Doppler technique to track optically the velocity of individual particles in a high Reynolds number turbulent flow. The particle sizes are of the order of the Kolmogorov scale and the time resolution, 30 microseconds, resolves the fastest scales of the fluid motion. Particles are tracked for mean durations of the order of 10 Kolmogorov time scales. The fastest scales of the particle motion are resolved and the particle acceleration is measured. For neutrally buoyant particles, our measurement matches the performance of the silicon strip detector technique introduced at Cornell University \cite{Voth,MordantCornell}. This reference dynamics is then compared to that of slightly heavier solid particles (density 1.4) and to air bubbles. We observe that the acceleration variance strongly depends on the particle density: bubbles experience higher accelerations than fluid particles, while heavier particles have lower accelerations. We find that the probability distribution functions of accelerations normalized to the variance are very close although the air bubbles have a much faster dynamics.
Crossed products for actions of crossed modules on C*-algebras  [PDF]
Alcides Buss,Ralf Meyer
Mathematics , 2013,
Abstract: We decompose the crossed product functor for actions of crossed modules of locally compact groups on C*-algebras into more elementary constructions: taking crossed products by group actions and fibres in C*-algebras over topological spaces. For this, we extend the theory of partial crossed products from groups to crossed modules; extend Takesaki-Takai duality to Abelian crossed modules; show that equivalent crossed modules have equivalent categories of actions on C*-algebras; and show that certain crossed modules are automatically equivalent to Abelian crossed modules.
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