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Journal articles on the topic 'String weight'

Author: Grafiati

Published: 4 June 2025

Last updated: 1 August 2025

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1

MELLOR, BLAKE. "INTERSECTION GRAPHS FOR STRING LINKS." Journal of Knot Theory and Its Ramifications 15, no. 01 (2006): 53–72. http://dx.doi.org/10.1142/s0218216506004361.

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We extend the notion of intersection graphs for chord diagrams in the theory of finite type knot invariants to chord diagrams for string links. We use our definition to develop weight systems for string links via the adjacency matrix of the intersection graphs, and show that these weight systems are related to the weight systems induced by the Conway and Homfly polynomials.

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2

Taylor, Skip. "An Investigation of Tone Production in Relation to Management of Bow Weight and Speed among Beginning and Intermediate String Players: A Pilot Study." String Research Journal os-3, no. 1 (2006): 55–66. http://dx.doi.org/10.1177/1948499206os-300105.

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Management of the bow to the point of achieving the most efficient physical interaction between the hair and strings is crucial to successful stringed instrument achievement and performance. Inferior tone production often restricts string students from achieving a totality of musically-acceptable performance skills. A spectral analysis of open string bowing was performed with middle school and high school string players in grades 6–10. Each subject bowed two separate down bows on the open violin A string. The specific objective was to investigate student control of bowed weight and speed manag

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3

Barton, Carl, Chang Liu, and Solon P. Pissis. "Fast Average-Case Pattern Matching on Weighted Sequences." International Journal of Foundations of Computer Science 29, no. 08 (2018): 1331–43. http://dx.doi.org/10.1142/s0129054118430062.

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A weighted string is a string in which a set of letters may occur at each position with respective occurrence probabilities. Weighted strings, also known as position weight matrices, weighted sequences or uncertain sequences, naturally arise in many contexts. In this paper, we study the problem of weighted string matching with a special focus on average-case analysis. Given a weighted pattern string [Formula: see text] of length [Formula: see text], a text string [Formula: see text] of length [Formula: see text], both on a constant-sized alphabet of size [Formula: see text], and a cumulative w

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4

Borerwe, Andrew Zivai, Portia Mupfumira, and Emmanuel Ndala. "Effects of drill pipe length and weight on bit on lateral and longitudinal vibrations." i-manager's Journal on Mechanical Engineering 13, no. 4 (2023): 1. http://dx.doi.org/10.26634/jme.13.4.20076.

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The vibration of a drill string is the topic under study in drilling and mining engineering. Drill string vibrations cause early failure of bits due to fatigue, drill pipe fracture and bearings damage. A modal and harmonic vibrational analysis of a drill string up to 60-65m long was done in a vertical water well by carrying out parametric studies. This paper investigates vibration of a drill string under longitudinal and mainly lateral which is the most dominant under the action of parameters such as drill pipe lengths and weight on bit. Finite element modelling of a drill string was made in A

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5

Soloviov, V. V., O. V. Mykhailovska, and I. A. Yermakova. "CONDITIONS OF A SINGLE INTAKE DESCENDING OF INTERMEDIATE CASING STRINGS OF AN EXCESSIVE WEIGHT COMPARED TO A DERRICK LOAD CAPACITY." ACADEMIC JOURNAL Series: Industrial Machine Building, Civil Engineering 1, no. 50 (2018): 214–19. http://dx.doi.org/10.26906/znp.2018.50.1078.

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The way of the intermediate casing string descending is considered. It allows overcoming the limits of derrick load capacity through the weight transferring descending intermediate casing string on the cemented string that is based on the foundation. In particular, technology is developed where the weight of each additional string, as it builds-up, is equivalent to additional friction forces which arise in the enlarged area. Such a descent technology does not depend on the load capacity of the derrick load capacity, does not create loads on the basis of derricks as well as additional tensile l

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6

Bao, Hua, Lingzhi Xia, Shengcong Chai, Yang Cheng, Songyuan Cao, and Zhiwen Lan. "Nonlinear Buckling Analysis and Optimization Design of the Y-Type Composite Insulator String." Advances in Civil Engineering 2022 (December 30, 2022): 1–15. http://dx.doi.org/10.1155/2022/4398388.

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Under the action of extreme wind load, the overhead transmission line will lead to the fracture of the traditional V-type insulator string, which greatly affects the safety of the power system. Compared with the V-type insulator string, the Y-type insulator string has better stability under the wind load. Therefore, the overhead lines in the mountainous areas of Anhui Province are taken as the research object, considering the combined effect of wind load and conductor dead weight, and through theoretical derivation, the calculation formula of insulator string wind deflection angle is obtained.

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7

Baier, Christel. "Verification Column." ACM SIGLOG News 10, no. 3 (2023): 3. http://dx.doi.org/10.1145/3617576.3617577.

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Many verification problems can be formulated as a language inclusion problem where the task is to decide whether the language of the system model (given by the runs of the system) is contained in the language induced by a logical specification. The corresponding verification problem for non-functional properties is the quantitative inclusion problem where both the system model and the specification are given by weighted automata and the task is to decide whether the weight for each input string in the automaton for the system is less than that in the automaton for the specification. Here, the

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8

Ihl, Matthias, Alexander Kling, and Sebastian Uhlmann. "String Field Theory Projectors for Fermions of Integral Weight." Journal of High Energy Physics 2004, no. 03 (2004): 002. http://dx.doi.org/10.1088/1126-6708/2004/03/002.

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9

Kling, Alexander, and Sebastian Uhlmann. "String field theory vertices for fermions of integral weight." Journal of High Energy Physics 2003, no. 07 (2003): 061. http://dx.doi.org/10.1088/1126-6708/2003/07/061.

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10

Huang, Kou‐Yuan, and Dar‐Ren Leu. "Recognition of Ricker wavelets by syntactic analysis." GEOPHYSICS 60, no. 5 (1995): 1541–49. http://dx.doi.org/10.1190/1.1443887.

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Syntactic pattern recognition techniques are applied to the analysis of 1-D seismic traces to classify Ricker wavelets. Seismic Ricker wavelets have structural information, and each wavelet can be represented by a string of symbols. To recognize the strings, we use a finite‐state automaton to identify each string. The automaton can accept strings having substitution, insertion, and deletion errors of the symbols. There are two attributes, terminal symbol and weight, in each transition of the automaton. A minimum‐cost, error‐correcting, finite‐state automaton is proposed to parse the input stri

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11

Sakit Abbasov, Fidan Mammadova, Sakit Abbasov, Fidan Mammadova. "INVESTIGATION OF THE STRESS STATE OF CASING PIPES IN DRILLED WELLS." ETM - Equipment, Technologies, Materials 26, no. 02 (2025): 37–46. https://doi.org/10.36962/etm26022025-37.

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The design features of casing pipe during descent and afloat are considered. A development model for studying the stress-strain state of the pipe in the zone of sticking with the bottom is presented. We consider design features of the casing during descent it afloat. The calculated model for the study of stress-strain state of pipes in the агеа of interface with the bottom.When drilling large-diameter wells, as a rule, the lifting capacity of the drilling rig is selected based on the weight of the casing string that is to be lowered into the well. If the weight of the string exceeds the liftin

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12

Jirapinyo, Pichamol, Paul Kröner, and Christopher Thompson. "Purse-string transoral outlet reduction (TORe) is effective at inducing weight loss and improvement in metabolic comorbidities after Roux-en-Y gastric bypass." Endoscopy 50, no. 04 (2017): 371–77. http://dx.doi.org/10.1055/s-0043-122380.

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Abstract Background and study aims Transoral outlet reduction (TORe), performed using a traditional interrupted or a recently described purse-string suture pattern, is effective at inducing short- and mid-term weight loss in patients with weight regain after Roux-en-Y gastric bypass (RYGB). We aimed to determine the technical feasibility and safety of purse-string TORe and to assess its impact on weight and metabolic profiles. Patients and methods RYGB patients undergoing purse-string TORe were included. The gastrojejunal anastomosis (GJA) was ablated using argon plasma coagulation or dissecte

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13

Ivanov, A. S. "Refining Eigenvalue Estimates for a String with a Singular Weight." Differential Equations 57, no. 10 (2021): 1292–98. http://dx.doi.org/10.1134/s0012266121100037.

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14

Ivanov, A. S., and A. M. Savchuk. "Trace of order (−1) for a string with singular weight." Mathematical Notes 102, no. 1-2 (2017): 164–80. http://dx.doi.org/10.1134/s0001434617070197.

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15

MELLOR, BLAKE. "WEIGHT SYSTEMS FOR MILNOR INVARIANTS." Journal of Knot Theory and Its Ramifications 17, no. 02 (2008): 213–30. http://dx.doi.org/10.1142/s0218216508006063.

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We use Polyak's skein relation to give a new proof that Milnor's string link invariants μ12⋯n are finite type invariants, and to develop a recursive relation for their associated weight systems. We show that the obstruction to the triviality of these weight systems is the presence of a certain kind of spanning tree in the intersection graph of a chord diagram.

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16

Brennan, F. P. "Fatigue of Drill String Connections." Journal of Offshore Mechanics and Arctic Engineering 117, no. 2 (1995): 126–32. http://dx.doi.org/10.1115/1.2827062.

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This paper reports full-scale tests on threaded connections used in drill strings. A concise background is given concerning the in-service environment and loading conditions on the connections. This details some of the reasons particular steels are used in preference to others. Crack growth data is given for ten full-scale axial and rotating bend tests. This is compared with predictions from a dedicated weight function fracture mechanics solution designed for threaded connections. Crack aspect ratio is considered with a view to development of an appropriate empirical model.

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17

Chirikutsi, Joshua. "Mitigating borehole drill string torsional vibration and shock." i-manager's Journal on Mechanical Engineering 13, no. 2 (2023): 1. http://dx.doi.org/10.26634/jme.13.2.18794.

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This paper provides an analysis of one of the dysfunctions in borehole drill strings, which is torsional vibration. Additionally, an analysis of mitigation through systematic adjustment of the key parameters of Weight on the Bit (WOB) and Rotations per Minute (RPM) is conducted. One of the key forms of dysfunction is undesired vibration and shocks on the drill strings. The vibration and shock experienced by drill strings have a detrimental impact on equipment life, resulting from damage to the drill bit and the drill string components. This paper studies a generalized lumped-parameter model of

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18

SHIRAISHI, KIYOSHI. "WILSON LOOPS IN OPEN STRING THEORY." Modern Physics Letters A 03, no. 03 (1988): 283–87. http://dx.doi.org/10.1142/s0217732388000337.

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Wilson loop elements on torus are introduced into the partition function of open strings as Polyakov’s path integral at one-loop level. Mass spectra from compactification and expected symmetry breaking are illustrated by choosing the correct weight for the contributions from annulus and Möbius strip. We show that Jacobi’s imaginary transformation connects the mass spectra with the Wilson loops. The application to thermopartition function and cosmological implications are briefly discussed.

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19

Катерина Григорівна Левчук. "The impact of heavy-weight drill pipe on the spectrum of longitudinal oscillations boring tool." MECHANICS OF GYROSCOPIC SYSTEMS, no. 28 (March 31, 2015): 82–91. http://dx.doi.org/10.20535/0203-377128201436750.

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When drilling holes in the operation breed destructive tool and drill string are destroyed as a result of elastic vibrations and static and external loads. Therefore, the actual problem is the study of the spectrum of natural vibrations of the drill string, depending on its layout (number of sections), the total length of the sections, the cross-section of drill pipe. The development of methods for determining the frequency range for each configuration of the drill string will predict the emergence of high-profile areas. The development of methods for determining the frequency range for each c

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20

Mahyari, M. F., M. Behzad, and G. R. Rashed. "Drill string instability reduction by optimum positioning of stabilizers." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 224, no. 3 (2009): 647–53. http://dx.doi.org/10.1243/09544062jmes1566.

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The main aim of this article is to find the optimum positions of the stabilizers that reduces the vibration and leads to the largest weight on bit (WOB) in drill strings. In this work, the potential energy of drill strings has been derived by considering the drill string weight and WOB. The potential energy of this continuous system is considered as a multi-degree-of-freedom system by the mode summation method. The equilibrium position of the system and its stability is determined by finding the roots of the first derivative and the sign of the second derivative of the potential energy, respec

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21

Ritto, T. G., C. Soize, and Rubens Sampaio. "Stochastic dynamics of a drill-string with uncertain weight-on-hook." Journal of the Brazilian Society of Mechanical Sciences and Engineering 32, no. 3 (2010): 250–58. http://dx.doi.org/10.1590/s1678-58782010000300008.

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22

Kotsireas, Ilias S., Christos Koukouvinos, and Panos M. Pardalos. "An efficient string sorting algorithm for weighing matrices of small weight." Optimization Letters 4, no. 1 (2009): 29–36. http://dx.doi.org/10.1007/s11590-009-0144-7.

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23

Slabyi, О. О. "A study of the influence deformation of the drilling riser on the longitudinal oscillations of the drill string." Oil and Gas Power Engineering, no. 2(32) (December 27, 2019): 18–28. http://dx.doi.org/10.31471/1993-9868-2019-2(32)-18-28.

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The article deals with the study of the effect of drilling riser transverse vibrations on the longitudinal vibrations of the drill string and the change of the dynamic component of weight on the bit when drilling wells from floating drilling vessel in deep sea conditions. The impact assessment was carried out by comparing the results of the simulation of the drilling system in the software based on the Modelica language. For this purpose, a simulation model has been created to enable the study of the operation of the «drill ship – riser wire tension system – drilling riser – drill string heave

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24

Vytyaz, O. Yu, R. S. Hrabovskyi, V. V. Tyrlych, and V. I. Artym. "Evaluation of the dynamic loads impact on the conditions of drill string failure during tripping operations." Scientific Bulletin of Ivano-Frankivsk National Technical University of Oil and Gas, no. 1(44) (February 16, 2018): 38–47. http://dx.doi.org/10.31471/1993-9965-2018-1(44)-38-47.

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The conditions of drill string failure during tripping operations with external or internal transverse annular cracks were defined. At the same time, considering the experimental evaluation of the force criterion for failure of metal of backup and operated drill string pipes, the interrelationship between the depth of the critical external or internal transverse annular cracks in drill string pipes with the weight of the drill string was established, considering the effect of dynamic loads during tripping operations. It was determined that dynamic loads during run-in-hole operations are more d

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25

Taheran, Farshad, Vahid Monfared, Saeed Daneshmand, and Esmaeil Abedi. "Nonlinear vibration analysis of directional drill string considering effect of drilling mud and weight on bit." Journal of Vibroengineering 18, no. 2 (2016): 1280–87. http://dx.doi.org/10.21595/jve.2015.16480.

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In this paper a nonlinear dynamic model for drill string in inclined well drilling is developed. Effects of drilling mud flow rate, weight on bit, angular velocity along with viscous damping on stability and vibration of the drill string are studied. Findings indicate the nonlinear effects are significant on the results. The effects of drilling mud flow rate and weight on bit on the natural frequencies and time responses are evaluated. Enhancement of drilling mud flow rate results in decreasing of natural frequencies and vibrational amplitude, while increasing the weight on bit, leads to decre

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26

He, Guolei, Linqing Wang, Jiarui Wang, et al. "Load Calculation and Strength Analysis of the Deepwater Landing Drill Pipe-Lowering Operation." Energies 17, no. 5 (2024): 1258. http://dx.doi.org/10.3390/en17051258.

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A landing string is directly exposed to seawater and subjected to significant stresses and complex deformations due to environmental loads such as wind, waves, and ocean currents during the phase in which the drill string carries the casing to the wellhead. Meanwhile, as the water depth increases, the weight of the drill string increases, leading to an increase in the tensile loads borne by the drill string, which can easily cause a risk of failure. Therefore, a quasi-static load calculation model for the deepwater insertion of the pipe column was established. Using the Ansys platform, simulat

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Abello, Margaux, Juliette Courson, Arnaud Maury, and Julian Renaud. "String Shooter’s overall shape in ambient air." Emergent Scientist 4 (2020): 1. http://dx.doi.org/10.1051/emsci/2019007.

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In this article, we study the behaviour of a looped string launched in ambient air using motorised wheels. We show that the loop, once it reaches its stationary state, is either in the pulley or the air-lifted state. The transition between these two distinct states occurs at the so-called takeoff speed. We prove that this speed differs from one string to another based on its characteristics. However, it is independent from the loop’s length and its initial launch angle. This speed indeed corresponds to the threshold where air drag starts compensating for the weight of the string.

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Ritto, Thiago G., and Maryam Ghandchi-Tehrani. "Active control of stick-slip torsional vibrations in drill-strings." Journal of Vibration and Control 25, no. 1 (2018): 194–202. http://dx.doi.org/10.1177/1077546318774240.

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This paper presents active vibration control to reduce the stick-slip oscillations in drill-strings. A simplified two degrees-of-freedom drill-string torsional model is considered. The nonlinear interaction between the rock and the bit is included in the model, where its parameters are fitted with field data from a 5 km drill-string system. Different proportional-derivative (PD)-control strategies are employed and compared, including the one that takes into account the weight-on-bit (axial force) and the bit speed. Optimization problems are proposed to obtain the values of the gain coefficient

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Zheng, Jinlong, Jiang Wu, Wei Wang, Siyuan Lin, and Guanrui Zhang. "Analysis of friction & torque and casing running measures of a well in the South China Sea considering joint effect." Thermal Science 28, no. 4 Part B (2024): 3499–504. http://dx.doi.org/10.2298/tsci2404499z.

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The mechanical properties of the rotary drilling system are analyzed in depth and the complex mechanical behaviors of integral tubular strings and the effects of joints are studied. The results show that before the mechanical calculation of the drilling string, the inversion of the friction coefficient by the near-well data can improve the calculation accuracy of the friction and torque of the string. Rotating casing can ensure smooth running in the extended well. The injection of light medium can alle?viate the axial force, but it is not enough to ensure safe running, which needs to be combin

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30

J, Ujwala Rekha, and Shahu Chatrapati K. "Probabilistic multiple correlation based term weighting scheme for measuring similarity of unstructured text records." Indian Journal of Science and Technology 13, no. 11 (2020): 1276–82. https://doi.org/10.17485/IJST/v13i11.2020-31.

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Abstract <strong>Background/Objectives:</strong> In this study, a term weighting scheme derived from probabilistic multiple correlation is defined for measuring similarity between unstructured text records. <strong>Methods:</strong> While the intra-correlation is the correlation of terms in the same record, inter-correlation is the correlation of terms that exist in different records. Probabilistic multiple correlation-based term weighting calculates the weight or relevance of a term by considering its intra-correlation with one or more terms simultaneously. Subsequently, the te

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31

Andrew, Zivai Borerwe. "Drill string vibrational analysis and parametric optimization for a portable water well rig development." i-manager's Journal on Mechanical Engineering 14, no. 2 (2024): 8. http://dx.doi.org/10.26634/jme.14.2.21011.

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The vibration of a drill string is a key topic of study in drilling and mining engineering. Excessive Drill String (DS) vibrations can lead to early failure of bits due to fatigue, Drill Pipe (DP) fractures, bearing damage, and a decrease in the Rate of Penetration (ROP). This occurs when the drill string rotates at its natural frequency, which is known as resonance. A modal and harmonic vibrational analysis of a drill string up to 60-65 meters long was conducted in a vertical water well through parametric studies. This project investigates the vibration of a drill string under various paramet

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Xu, Chanchan, Tong Liu, Shuai Dong, Yucheng Wang, and Xiaojie Wang. "A Lightweight, Simple-Structure, Low-Cost and Compliant Twisted String Actuator Featuring Continuously Variable Transmission." Actuators 13, no. 12 (2024): 477. http://dx.doi.org/10.3390/act13120477.

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Twisted string actuators, which are an emerging artificial muscle, efficiently convert rotary motor motion into linear load movement, with advantages like high transmission ratio, compliance, simple structure, and long-distance power transmission. However, the limited range of transmission ratio adjustment remains a challenge. Thus, this paper introduces a novel twisted string actuator design that automatically and continuously adjusts its transmission ratio in response to external loads. Utilizing lightweight hyperelastic slender rods, the twisted string actuator with continuously variable tr

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33

KUMAR, K. MANOJ, V. DEVI PRASAD, N. DHANA LAKSHMI, and N. K. B. RAJU. "Management of distal femoral diaphyseal fractures with string of pearls locking plate in dogs." Indian Journal of Animal Sciences 88, no. 2 (2018): 157–60. http://dx.doi.org/10.56093/ijans.v88i2.79297.

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Distal femoral diaphyseal fractures in 6 dogs about 10–22 months old with body weight ranging from 12–25 kg were stabilized using String of Pearls (SOP) locking plates along with standard cortical and cancellous screws following standard AO/ASIF principles. Selection of appropriate size of plate and screws was according to body weight and type of fracture (2.7 mm plate for dogs below 12 kg body weight and 3.5 mm plate for dogs above 12 kg body weight) which provided good fracture stability. The outcome of fracture stabilization and healing was evaluated with lameness grading and radiography. P

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Ivanov, A. S. "Traces of Higher Negative Orders for a String with a Singular Weight." Differential Equations 54, no. 10 (2018): 1310–20. http://dx.doi.org/10.1134/s0012266118100038.

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Ahrami, Mohammed, Zakaria El Allali, and Jamal Ounejma. "Lower bounds on the eigenvalue ratio with Robin boundary conditions." Gulf Journal of Mathematics 19, no. 2 (2025): 489–99. https://doi.org/10.56947/gjom.v19i2.2825.

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We study the problem of minimizing the ratio of the first eigenvalues of vibrating string equations subject to the Robin boundary conditions for the class of concave weights. We show that, unlike the Dirichlet, Neumann and mixed boundary conditions, the constant weight is not minimizing for the class of concave weights. In addition, we prove a relation between the eigenvalues and real roots of the first Airy functions and their derivatives.

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Clark, Alexander, and Chris Watkins. "Some Alternatives to Parikh Matrices Using String Kernels." Fundamenta Informaticae 84, no. 3-4 (2008): 291–303. https://doi.org/10.3233/fun-2008-843-401.

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We describe methods of representing strings as real valued vectors or matrices; we show how to integrate two separate lines of enquiry: string kernels, developed in machine learning, and Parikh matrices [8], which have been studied intensively over the last few years as a powerful tool in the study of combinatorics over words. In the field of machine learning, there is widespread use of string kernels, which use analogous mappings into high dimensional feature spaces based on the occurrences of subwords or factors. In this paper we show how one can use string kernels to construct two alternati

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Kochkodan, Ya M., and A. I. Vasko. "The Study of the Interaction of Different Arrangements of the Bottom-Hole Assembly with the Bottomhole and the Borehole Wall." Prospecting and Development of Oil and Gas Fields, no. 3(72) (September 30, 2019): 58–68. http://dx.doi.org/10.31471/1993-9973-2019-3(72)-58-68.

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The article presents the main factors affecting the buckling when drilling vertical wells. The authors study analytically the effect of the weight on the bit and the force of the interaction of a drill string with a borehole wall using a uniform-sized arrangement of the bottom-hole assembly and the borehole wall which is located in a deviated wellbore when drilling in isotropic rocks in case the drilling direction coincides with the direction of the force acting on the bit. Differential equations of the elastic axis of the drill string are worked out. The solutions of these equations have give

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BEIVYDAS, Edmundas. "Parametrical Analysis for Symmetrical Loading of a Single-Span Composite String Steel Structure." Eurasia Proceedings of Science Technology Engineering and Mathematics 17 (September 16, 2022): 90–101. http://dx.doi.org/10.55549/epstem.1176065.

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The article analyzes the string and composite string bridge behavior and compositional parameters. The derived parameters are calculated and presented by selecting the appropriate limit parameters. The main parameters for suspended structures are the cross-sectional area of the tensile element and the initial sag of the structure. The selection of different component parameters and assigning different prestressing to the string leads to the analysis: which cross-sectional areas meet the defined conditions, what is the effect of prestressing, of the lower cable initial sag and the axial stiffne

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Kachru, Shamit, and Arnav Tripathy. "Black holes and Hurwitz class numbers." International Journal of Modern Physics D 26, no. 12 (2017): 1742003. http://dx.doi.org/10.1142/s0218271817420032.

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We define a natural counting function for BPS black holes in [Formula: see text] compactification of type II string theory, and observe that it is given by a weight 3/2 mock modular form discovered by Zagier. This hints at tantalizing relations connecting black holes, string theory, and number theory.

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40

ERDENEBAYAR, D. "AN EXAMPLE OF HIGHER WEIGHT SUPERPOTENTIAL INTERACTION IN THE HETEROTIC STRING ON ORBIFOLDS." International Journal of Modern Physics A 10, no. 25 (1995): 3627–48. http://dx.doi.org/10.1142/s0217751x95001728.

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An explicit orbifold example of the nonzero correlation functions related to the additional contribution to the induced mass term for Higgs particles at low energies is given. We verify that they form finite-dimensional representations of the target space modular transformation SL 2(Z). This action of the modular group is shown to be consistent with its action on the fixed point set defining the twisted fields.

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41

FERRARI, FRANCO. "STRING THEORIES ON RIEMANN SURFACES OF ALGEBRAIC FUNCTIONS." International Journal of Modern Physics A 05, no. 14 (1990): 2799–820. http://dx.doi.org/10.1142/s0217751x90001306.

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In this paper we extend to a general Riemann surface a formalism used so far for surfaces with Abelian group of symmetry. Using an algebraic equation F(z, w)=0 to define the surface in terms of sheets and branch points, it is possible to construct the correlation functions for b—c systems with integer conformal weight j and for the scalar fields X. Explicit examples are provided for a general surface of genus three and a surface of genus four. No essential complication arises with respect to the hyperelliptic case. At the end we discuss the computation of chiral determinants det [Formula: see

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WEST, PETER. "ON THE SPECTRUM, NO-GHOST THEOREM AND MODULAR INVARIANCE OF W3 STRINGS." International Journal of Modern Physics A 08, no. 17 (1993): 2875–93. http://dx.doi.org/10.1142/s0217751x93001168.

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A spectrum-generating algebra is constructed and used to find all the physical states of the W3 string with standard ghost number. These states are shown to have positive norm and their partition function is found to involve the Ising model characters corresponding to the weights 0 and 1/16. The theory is found to be modular invariant if, in addition, one includes states that correspond to the Ising character of weight 1/2. It is shown that these additional states are indeed contained in the cohomology of Q.

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Long, Yuan, Xueying Wang, Peng Wang, and Feifei Zhang. "A Method of Reducing Friction and Improving the Penetration Rate by Safely Vibrating the Drill-String at Surface." Processes 11, no. 4 (2023): 1242. http://dx.doi.org/10.3390/pr11041242.

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Drill-string axial vibration at the surface technology is proposed to reduce the friction between the drill-string and the borehole wall, and to improve load transfer efficiency, the rate of penetration (ROP), and the extended-reach limit of a horizontal well. An analytical framework utilizing the “soft-string” model is constructed. The results obtained from numerical simulations reveal that during the slide drilling operation, the drill-string experiences an axial stick–slip motion, and the weight on bit (WOB) undergoes periodic oscillations. The conventional calibration method of the WOB in

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Ito, So, Kang Won Lee, Yuki Shimizu, and Wei Gao. "Improvement of an Air-Bearing Displacement Sensor with Nanometric Resolution." Key Engineering Materials 523-524 (November 2012): 945–50. http://dx.doi.org/10.4028/www.scientific.net/kem.523-524.945.

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A contact stylus-type displacement sensor is proposed for a surface form measurement of micro-structures. The stylus is supported by an air-bearing, thus it can be moved smoothly without friction between the stylus and the air-bearing. In order to reduce the measurement force, a novel controlling technique of a contact force has been developed. During the measurement one edge of the stylus is maintained contact with the measured surface by its own weight. Another end of the stylus is connected with a counter weight by a string and the stylus is hanging on the string in order to reduce the cont

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ANTONOV, D. V. "NONPERTURBATIVE FIELD CORRELATOR AND STRING REPRESENTATION FOR THE 't HOOFT LOOP AVERAGE IN THE ABELIAN HIGGS MODEL." Modern Physics Letters A 13, no. 09 (1998): 659–71. http://dx.doi.org/10.1142/s0217732398000711.

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Making use of the duality transformation, we derive in the Londons' limit of the Abelian Higgs model string representation for the 't Hooft loop average defined on the string worldsheet, which yields the values of two coefficient functions parametrizing the bilocal correlator of the dual field strength tensors. The asymptotic behaviors of these functions agree with the ones obtained within the method of vacuum correlators in QCD in the lowest order of perturbation theory. We demonstrate that the bilocal approximation to the method of vacuum correlators is an exact result in the Londons' limit,

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Zhang, Hui Zeng, Zhi Chuan Guan, Yu Qiang Xu, Qian Deng Li, and Ling Chao Xuan. "Research Progress of Extended-Reach Well Antifriction Technology." Advanced Materials Research 868 (December 2013): 638–44. http://dx.doi.org/10.4028/www.scientific.net/amr.868.638.

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There is a remarkable friction between drill string and borehole in extended-reach wells and horizontal wells due to large deviation angle, contact between drill string and borehole, non-rotation of drill string. The large friction and torque will induce blocked bit weight, low ROP, constrained drill string extension. This article summarizes the common used antifriction methods and tools in extended-reach wells, focusing on Non-Rotation Drill Pipe Protector (NRDPP), roller antifriction tools and vibration antifriction tools. The working principle, structure design, performance and field applic

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Zhou, Hai Bo, Ping Liu, and Guan Ze Hou. "Study on Searching the Best Rise of Truss String Structure by Using Fibonacci Method." Advanced Materials Research 250-253 (May 2011): 1556–60. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.1556.

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In order to discuss the relationship between truss string structure weight and the rise, so as to find out the optimal rise of different spans, Fibonacci search method is used to write truss string structure optimization program which takes the rise as variable. To effectively improve search efficiency and ensure the accuracy, the dynamic search interval is introduced when writing the Fibonacci search program. This paper use Fibonacci to search the optimal rise in span of 100m of truss string structure, meanwhile analysis the dynamic search interval, the analysis results show that the approxim

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TARUMA, ARVIN BUEMIA, and MARY GRACE BROSO BALINQUIT. "PERFORMANCE OF STRING BEANS AS AFFECTED BY DIFFERENT LEVELS OF CHICKEN MANURE TEA." International Journal Of Multidisciplinary Research And Studies 05, no. 09 (2022): 01–09. http://dx.doi.org/10.33826/ijmras/v05i09.1.

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This study was conducted to look for alternative measures to sustain the profitability of cultivating string beans by using different levels of chicken manure tea. Experimental Research in Randomized Complete Block Design (RCBD) was used in this study of different levels of chicken manure tea as treatment. The treatments used were as follows: Control (T1), Chicken manure tea at 25%: 75% water dilution (T2), Chicken manure tea at 50%: 50% water dilution (T3), and Pure chicken manure tea (T4). The results show that growth characteristics such as the number of days from sowing to flowering, to fr

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Tirasuntarakul, Narongsak, and Arbtip Dheeravongkit. "Design and Analysis of a Micro Actuating Mechanism Driving Multi-Degree of Freedom." Applied Mechanics and Materials 851 (August 2016): 464–69. http://dx.doi.org/10.4028/www.scientific.net/amm.851.464.

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This paper presents design concept and implementation of a micro actuating mechanism that uses a single drive to operate many degrees of freedom. The challenge of this research is to reduce the complexity of the multi-dof actuator mechanism in order to optimize its size and weight so that it is small and light enough to be implemented on other robots or automatic systems where mobility is needed. For example, on the development of the automatic tuning system of multi-string music instruments like piano or harp, instead of implementing one actuator to tune each string, this paper proposed an ac

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AHN, CHANGHYUN. "${\mathcal N} = 2$ CONFORMAL SUPERGRAVITY FROM TWISTOR-STRING THEORY." International Journal of Modern Physics A 21, no. 18 (2006): 3733–59. http://dx.doi.org/10.1142/s0217751x06033787.

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A chiral superfield strength in [Formula: see text] conformal supergravity at linearized level is obtained by acting two superspace derivatives on [Formula: see text] chiral superfield strength which can be described in terms of [Formula: see text] twistor superfields. By decomposing SU (4)R representation of [Formula: see text] twistor superfields into the SU (2)R representation with an invariant U (1)R charge, the surviving [Formula: see text] twistor superfields contain the physical states of [Formula: see text] conformal supergravity. These [Formula: see text] twistor superfields are funct

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