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With the increasing demands of ultra‐large space antennas, on‐orbit assembly stands out as a promising solution. However, this achievement necessitates the reconfiguration design of the whole antenna structure to maintain structural integrity and stability. In light of this challenge, a novel rapid design method is proposed for the unit configuration of modular‐assembled antennas in this paper. The method utilizes an inscribed regular hexagon, which is positioned within a horizontal topological circle. The hexagon is subsequently projected onto a spinning paraboloid, resulting in the creation of unit nodes that conform to the shape of the paraboloid. The configuration of the unit topology is then determined based on the arrangement of these nodes. By using the method, two units of space‐assembled antennas are designed. The topology design of the cable network is carried out for the modular unit. The pretensions of the cables are calculated. The results of the case study reveal that the developed modular units fulfill the requirements of the on‐orbit‐assembly antenna structure and can solve the engineering application difficulties of this type of antenna. [ABSTRACT FROM AUTHOR]

In this study, the mechanical behavior of novel fully grouted cable rock bolts made of basalt fiber–reinforced polymer (BFRP) was investigated, which included pullout and double-shear joint behavior. Three BFRP cables were prepared: (1) single-tendon; (2) untwisted multiple-tendon; and (3) twisted multiple-tendon. In the pullout tests, the effects of cable type, borehole diameter, and encapsulated length were studied. However, the influence of the pretension load level was focused on in the double-shear joint tests. The results suggested that an overly thick grout annulus significantly reduced the pullout strength and stiffness. For the BFRP cable with multiple tendons, the initial pullout stiffness was enhanced compared with the BFRP cable with a single tendon due to better interfacial bonding with the grout. In the double-shear joint tests, the pretension of the cable significantly improved the shear capacity and stiffness. With an enhancement in the confinement from pretension, the partial failure of the grout at an early stage could be prevented. The parallel and twisted-tendon BFRP cable rock bolts had larger failure displacements than the single-tendon cable. This analytical study found that a pullout analytical model available in the literature was accurate when back-calculating the stress conditions along the rock bolt. The predicted shear capacity of the rock joint showed good agreement with the experimental values. A parametric study indicated that the joint shear capacity was sensitive to the tensile and shear strengths of the cable but was irrelevant to the cable moduli. Considering the effectiveness of pretension and creep safety for BFRP, a suitable range for the pretension load was suggested. Practical Applications: This study attempts to promote the use of novel, fully grouted cable rock bolts made of basalt fiber–reinforced polymer (BFRP) materials in geotechnical engineering applications. Different types of cable rock bolts are produced, which include single-tendon, untwisted multiple-tendon, and twisted multiple-tendon cables. In the pullout tests, the untwisted multiple-tendon cable exhibited the highest pullout capacity, because of its better interfacial bonding with the grout. From the double-shear joint tests, the pretension of the cable could significantly improve the shear capacity and stiffness. In general, the BFRP cable rock bolts could have a competitive mechanical behavior compared with the steel rock bolts. The respective analytical models for pullout and double-shear joint specimens have proved to be accurate for predicting the mechanical responses of the cable rock bolts. These concise but reliable analytical models could allow researchers and designers to better utilize these novel cable rock bolts in potential applications. [ABSTRACT FROM AUTHOR]

Roller chain drives are frequently applied in a variety of machinery for mechanical motion and power transmission. The roller engagement location on the sprocket tooth contour and the resulted contact behavior is governed by the wear of components and pretension of the chain. Therefore, the influence of extension of chain resulted from wear and pretension of chain on contact behavior was investigated numerically using explicit dynamics module of ABAQUS software. The contact angles evaluated from the numerical simulation were assessed relative to those obtained from the basic rigid body analytical formulation. The chain elongation of 3% increased the maximum contact force up to 52% during engagement with the driver sprocket. The contact force raised to 400% when the pretension in the chain drive was increased from 200 to 1000 N, leaving the force distribution pattern unaltered. The optimal design of a steel sprocket is realized through equivalent static finite element contact analysis of a sprocket engaged with 3% extended roller chain. The dynamic finite element analysis in conjunction with topology optimization reduced the weight of the sprocket by 24%. [ABSTRACT FROM AUTHOR]

This study explores the stiffness enhancement in textile composites using four different fiber types: carbon, Kevlar, Vectran, and high-tenacity polyester (HTP). Pretension levels of 0.2, 2, 5, and 10 N were applied. A setup was developed to measure fiber stiffness. Results indicate that carbon fiber consistently demonstrates the highest stiffness across all pretenstionlevels, attributable to its high tensile strength and modulus. Kevlar fiber, although initially less stiff than carbon, exhibits the most substantial increase in stiffness, particularly between 5 and 10 N of pretension, reaching a peak stiffness of 33.8 at 10 N. Vectran fiber shows a gradual increase in stiffness, surpassing HTP but slightly lagging behind carbon and Kevlar. The rates of yarn-specific bending stiffness increase were measured as 0.168 for HTP, 0.054 for carbon fiber, 0.173 for Kevlar fiber, and 0.191 for Vectran fiber. The study highlights the importance of understanding how yarn pretension affects the bending stiffness of yarn-polymer composites, which is crucial for advancements in textile engineering. It was found that variations in the bending stiffness of HTP and carbon fibers significantly impacted the composite bending stiffness more than Vectran and Kevlar fibers under pretension during composite formation. High-stiffness yarns were less influenced by increasing pretension during composite fabrication. The study suggests utilizing yarn pretension to control the stiffness of textile/polymer composites and proposes individually tensioning and pultruding fibers or yarns in the polymer matrix before composite formation. A specialized setup for achieving this during the protrusion process is recommended. [ABSTRACT FROM AUTHOR]

El artículo estudia los alcances de la prescripción regulada en el artículo 1989 del Código Civil peruano, el cual establece que “La prescripción extingue la acción, pero no el derecho mismo”. A través de un análisis detallado, los autores exploran las diferencias entre acción y pretensión, así como la relevancia del transcurso del tiempo en la prescripción. De ese modo, examinan el concepto de derecho subsistente, pero no exigible y su tratamiento en el sistema jurídico peruano. La conclusión principal es que aunque la prescripción afecta la exigibilidad de la pretensión, el derecho de acción no se extingue y sigue siendo accesible en futuros procesos judiciales.

Earthquakes occur without warning and cause considerable shock to structures by shaking the ground. If deformation or damage beyond the permissible range occurs in a structure owing to an earthquake, serious problems arise in terms of usability, repair, and reinforcement. Therefore, numerous seismic reinforcement devices have been developed to prevent structural damage caused by earthquakes. However, the existing seismic reinforcement devices are problematic because they need to be replaced after an earthquake owing to deformation. Therefore, in this study, we developed a pretension damper, a seismic reinforcement device that exhibits excellent recentering, load resistance, and energy dissipation capacity performances by applying superelastic shape memory alloy wire with pretension and friction bolts, and analyzed the behavior characteristics. For this purpose, the design parameters set as the diameter and material of the wire, pretension, and friction bolts. Finite element analysis was performed using the ABAQUS program for a total of 24 dampers according to design parameters, and maximum load performance, energy dissipation capacity, residual displacement was analyzed. The results confirmed that the recentering and load resistance performance are improved when pretension is applied, and the energy dissipation performance is improved when friction bolts are installed. Applying the superelastic shape memory alloy instead of Gr. 50 steel enhances the damper performance in terms of the maximum force, energy dissipation capacity, and residual displacement. In particular, when pretension is applied to Gr.50 steel wire, performance deteriorates, so pretension is not recommended in this case. In particular, the application of pretension to Gr.50 steel wire is not recommended due to reduced performance. The best performance was SPF20 damper, which showed a maximum load of 1153.7 kN, residual displacement of 0 mm, and energy dissipation capacity of 309855.19 kN·mm.

This study explores the effects of dynamic and static loading on rock bolt performance a key factor in maintaining the structural safety of coal mine roadways susceptible to coal bursts. Employing a house-made load frame to simulate various failure scenarios, pretension-impact-pull tests on rock bolts were conducted to scrutinize their dynamic responses under varied static load conditions and their failure traits under combined loads. The experimental results denote that with increased impact energy, maximum and average impact loads on rock bolts escalate significantly under pretension, initiating plastic deformation beyond a certain threshold. Despite minor reductions in the yield load due to impact-induced damage, pretension aids in constraining post-impact deformation rate and fluctuation degree of rock bolts. Moreover, impact-induced plastic deformation causes internal microstructure dislocation, fortifying the stiffness of the rock bolt support system. The magnitude of this fortification is directly related to the plastic deformation induced by the impact. These findings provide crucial guidance for designing rock bolt support in coal mine roadway excavation, emphasizing the necessity to consider both static and dynamic loads for improved safety and efficiency.

Copyright of Themis: Revista de Derecho is the property of Themis Asociacion and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Recently, offshore structures for eco-friendly energy, such as wind and solar power, have been developed to address the problem of insufficient land space; in the case of energy generation, they are designed on a considerable scale. Therefore, the scalability of offshore structures is crucial. The Korea Research Institute of Ships & Ocean Engineering (KRISO) developed multi-linked floating offshore structures composed of floating bodies and connection beams for floating photovoltaic systems. Large-scale floating photovoltaic systems are mainly designed in a manner that expands through the connection between modules and demonstrates a difference in structural response with connection conditions. A fluid–structure coupled analysis was performed for the multi-linked floating offshore structures. First, the wave load acting on the multi-linked offshore floating structures was calculated through wave load analysis for various wave load conditions. The response amplitude operators (RAOs) for the motions and structural response of the unit structure were calculated by performing finite element analysis. The effects of connection conditions were analyzed through comparative studies of RAOs and the response’s maximum magnitude and occurrence location. Hence, comparing the cases of a hinge connection affecting heave and pitch motions and a fixed connection, the maximum bending stress of the structure decreased by approximately 2.5 times, while the mooring tension increased by approximately 20%, confirmed to be the largest change in bending stress and mooring tension compared to fixed connection. Therefore, the change in structural response according to connection condition makes it possible to design a higher structural safety of the structural member through the hinge connection in the construction of a large-scale multi-linked floating offshore structure for large-scale photovoltaic systems in which some unit structures are connected. However, considering the tension of the mooring line increases, a safety evaluation of the mooring line must be performed.

Dentro de las tesis que definen la metafísica de Leibniz, destaca aquella según la cual las esencias encierran una pretensión a la existencia. Esta tesis ha despertado un singular interés entre los comentaristas de Leibniz, dando origen a un debate que enfrenta a aquellos que defienden una interpretación metafórica con aquellos que profesan una interpretación literal: si el primer grupo sostiene que tal pretensión ha de entenderse como una atribución metafórica en virtud de la cual las esencias, desprovistas de tal característica, son susceptibles de alcanzar la existencia al ser actualizadas por Dios, para el segundo grupo, las esencias son portadoras en sí de tal característica, la que debe entenderse entonces como una cualidad real e inherente presente en ellas. A partir de un examen de diversos manuscritos de Leibniz, nuestro propósito es reivindicar una interpretación literal de la tesis de la pretensión de las esencias a la existencia, explicando por qué la interpretación metafórica, además de carecer de fundamento, entraña contradicciones.

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The compression deformation of the measuring membrane of the differential pressure capacitance sensor is studied. The classical von Kármán thin plate theory is applied to the elastic circular thin plate subjected to pretension, and the approximate analytical solution is given by adopting the homotopy analysis method. The results are compared with the simulation results of the finite element software ANSYS, which shows that they have a high degree of agreement. The magnitude of pretension has a great influence on the deformation of the membrane under compression, thus affecting the capacitance output characteristics of the sensor. The effect of pretension on the nonlinear characteristic of the sensor is verified by the sensor performance test. The results suggest that the linearity of the sensor can be effectively improved by selecting the appropriate pretension, and the sensitivity of the output can be improved by appropriately reducing the membrane thickness. The analysis results have an important reference value for the design of membrane of differential pressure capacitance sensors.

In deep ground engineering, the use of high-strength and high-toughness steels for rock bolt can significantly improve its energy absorption capacity. However, the mechanisms and effects of rock loading conditions on this kind of high energy-absorbing steel for rock bolt remain immature. In this study, taking Muzhailing highway tunnel as the background, physically based crystal plasticity simulations were performed to understand the effect of rock loading rate and pretension on the deformation behaviors of twinning induced plasticity (TWIP) steel used for rock bolt. The material physical connecting to the underlying microscopic mechanisms of dislocation glide and deformation twinning were incorporated in numerical modeling. The rock loading conditions were mimicked by the real-time field monitoring data of the NPR bolt/cable equipment installed on the tunnel surrounding rock surface. The results indicate that the bolt rod exhibits pronounced deformation-softening behavior with decrease of the loading rate. There is also a sound deformation-relaxation phenomenon induced by the dramatic decrease of loading rate after pre-tensioning. The high pretension (>600 MPa or 224 kN) can help bolt rod steel resist deformation-softening behavior, especially at low loading rate (

Wetting of a liquid droplet on another liquid substrate is governed by the well-known Neumann equations. The present work aims to develop an explicit modified version of the Neumann equations for axisymmetric wetting of a liquid droplet on a highly stretched elastic membrane of non-zero bending rigidity. An explicit modified form of the Neumann equations is derived to determine the two contact angles, which is reduced to Young's equation for a liquid droplet on a rigid membrane or to the Neumann equations for a liquid droplet on another liquid substrate. Further implications of the modified Neumann equations are examined by comparison with some previous results reported in the recent literature, particularly considering the ranges of material and geometrical parameters of the liquid droplet-membrane system which have not been recently addressed in the literature. [ABSTRACT FROM AUTHOR]

Resumen En el derecho procesal se discute sobre el rol que debe desempeñar el juez dentro del juicio. Por una parte, un juez activo; por otra, un juez garantista que deja el protagonismo a las partes, considerando que de esa forma se materializa la igualdad y la imparcialidad. Por esta razón, se formuló como problema de investigación: ¿Cuál es el sistema procesal y el concepto de finalidad del proceso que define el rol del juez en el proceso contencioso administrativo colombiano? Se propone analizar, desde el interior de las instituciones procesales, las cargas y deberes del juez y de las partes, partiendo de la hipótesis de que no existen linderos que permitan definir con precisión la naturaleza del sistema procesal y el concepto de finalidad de proceso al que debe acudir el juez para el ejercicio de su función. Para ello se adelantó un estudio exploratorio-analítico de las normas aplicables. El resultado de tal análisis es que el rol del juez en el proceso contencioso administrativo no lo define ni el sistema procesal ni los conceptos de la finalidad del proceso, sino que se debe a la naturaleza jurídica de la pretensión o medio del control.

Copyright of Journal of Shanghai Jiao Tong University (1006-2467) is the property of Journal of Shanghai Jiao Tong University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Direito GV is the property of Fundacao Getulio Vargas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Filament yarn is one of the most widely used soft strands in the textile industry; it exhibits excellent flexibility and is capable of being used in various productions, including knitting, weaving, braiding, sewing, and embroidery. The inherent complex interlacement between fibers, including twist, entanglement, and yarn geometry, often exhibits a nonlinear response to external loads. In addition, the interlacement of fibers also introduces difficulties when accurately measuring the flexural property of multi-filament yarn. In particular, the flexural rigidity of the yarn strongly influences the quality of end products when incorporated into novel textile technologies. In this paper, we developed a three-point bending instrument and a method for measuring the flexural rigidity of filament yarn. A representative point obeyed from Coplan's construction on the bending constitutive curve was determined to obtain pure flexural rigidity. Furthermore, the bending process and deformations across cross-sections of filament yarns were discussed. The research provides new physical insights into the yarn bending property with the consideration of eliminating the sub-deformation variabilities. The work also paves the way for the accurate and quick measurement of the flexural rigidity of high length-to-width ratio soft materials by a three-point bending method. [ABSTRACT FROM AUTHOR]

The wind deflection of the sealing net across the transmission line is great under the slipstream of high-speed train. Based on the existing research， the paper proposes a method to reduce the wind deflection response of the sealing net structure by using the inclined wind vibration control cable， and it establishes a numerical model of dynamic response with wind analysis model and the sealing network structure of high-speed train coupled. Moreover， it studies the effect of the inclined wind vibration control cable on the wind deflection control of the sealing net structure and compares the effect with that of the vertical wind vibration control cable without inclined guy cable. The results show that under the action of coupled high-speed train wind， the pretension of the bearing cable has a significant effect on the horizontal and vertical wind deflection of the sealing net， especially the vertical wind deflection control of the sealing net， which can be reduced by 90% or more， but the safety coefficient of the bearing cable will be reduced by excessive large pretension force； the proposed schemes of using the inclined wind vibration control cable and the vertical wind vibration control cable are about the same in the control effect， and both can effectively control the upper and lower wind deflection of the sealing network. The control effect is more significant in the working condition of smaller carrier cable pretension.

A quench boiler is the key equipment in ethylene production for the rapid cooling of high-temperature cracking gas. In the boiler, heat transfer is occurs between the hot cracking gas passing through the inner heat exchange tubes with an average temperature of 385 °C and cold water (or boiler water) passing through the inner heat exchange tubes with an average temperature of 350 °C. Required for double-pipe heat transfer, special tubesheets formed by welding flat-round tubes side by side are difficult to design, as no suitable design code is available. The thermal expansion difference between the inner heat exchange tubes and the jacketed tubes could lead to high thermal stress on the tubesheet. In this study, we investigated the effects of pretension or prestretching of the heat exchange tubes on stress distribution and strength assessment of the flat-round tubesheet in a quench boiler under two dangerous load conditions. Results show that without prestretching the heat exchange tubes, the flat-round tubesheet cannot pass the strength assessment. Prestretching the heat exchange tubes is necessary, and a pretension of 9 mm is most suitable. The magnitude of the pretension of the heat exchange tubes should be determined based on the thermal expansion difference between the inner heat exchange tubes and the jacketed tubes, with consideration of the strength improvement of the flat-round tubesheet. [ABSTRACT FROM AUTHOR]

La presente investigación se fundamenta en un análisis dogmático y normativo de la Acción Contencioso Administrativa de Plena Jurisdicción en el derecho positivo panameño, el cual tiene su génesis en la Constitución de 1946, que crea la Jurisdicción Contencioso Administrativa en Panamá, como tribunal de única instancia, independiente de los demás órganos del Estado, que tenía como misión garantizar el control de legalidad de las actuaciones de las entidades del sector público, y en caso de haberse conculcado algún derecho subjetivo por la actuación ilegal de la administración pública, su objetivo principal es restablecer o reparar el derecho violado. Esta acción va dirigida a impugnar actos administrativos que hayan vulnerado, directamente, derechos de particulares; por lo tanto, todo aquel que interponga el proceso en mención, debe solicitar el restablecimiento del derecho quebrantado y especificar las pretensiones que se pretenden con el proceso. En ese sentido, se conocerá el concepto de la acción objeto de este artículo, además de realizar un análisis de las características, presupuestos procesales generales y fundamentales para la presentación de la acción y los requisitos de forma que debe contener toda demanda que se instaure ante la Sala Tercera de lo Contencioso Administrativo en Panamá.

In this paper, a newly developed test method to evaluate the influence of corrosion on pretension and fatigue of bolted connections is presented, suitable from size M36 to M72. A first preliminary series of M30 property class 10.9 bolts were tested to validate the individual test setup steps and to detect challenges and improvement. Pretension load tests, static load tests and fatigue load tests were performed while monitoring stresses on a small number of bolts. The method presented is used to compare different coatings for bolts, like Hot‐dip galvanized coatings and zinc flake coatings, as well as nano‐coatings. To create a realistic approach on offshore corrosion and loading conditions, the bolts will be preloaded in a clamping device resembling the ring flange of an offshore wind tower segment. In a next step, the bolts are corroded in a climate chamber, using the salt spray test or condensation test. Following the corrosion process, the bolts are tested for fatigue without loosening the nut and damaging the thread. Before corrosion and after the fatigue test, 3D surface scans are made to document the corrosion process and to create numerical models of the corroded surface. The method presented offers a new way to evaluate fatigue, pretension and corrosion effects, which is validated on bolts M30 property class 10.9. In close future, the test method is used for larger series of corroded M36 property class 10.9 bolts, having different coating systems applied. [ABSTRACT FROM AUTHOR]

The unique properties along with ease of manufacturing make short fiber reinforced polyamide 66 composites ideal for sprockets used in low positive power transmission. An explicit dynamic finite element simulation of short fiber reinforced polyamide 66 composite sprocket—roller chain drive was carried out. The sprocket was approximated as a plane stress body and roller was considered as a rigid circle. The contact force extracted from the numerical simulation was validated with the analytical results for a standard chain. The deviations in the pitch of the chain produced a varied dynamic contact behavior in terms of a distinct contact width and pressure distribution pattern. The position of maximum contact shear stress altered from subsurface to surface due to low contact normal stress and associated slip. The variation in the chain pitch (up to 3%) affected the peak force of driver sprocket significantly (up to 41%). The increase of pretension of roller chain from 100 to 300 N induced the rise in contact force of driver sprocket up to 169% without changing the pattern. [ABSTRACT FROM AUTHOR]

Tendon drive is used for transmission design in applications ranging from wearable rehabilitation and surgical robots to industrial robots. For their efficient operation, one of the principal design requirements is to have adequate tension in the tendon element. This paper introduces a novel mechanism for tension adjustment using a secondary cable-pulley arrangement via a lever mechanism. An adjustment in a tension spring applies a force in the tendon element meant for the transmission of remote centre-of-motion (RCM) mechanism for medical robotic application. Thereafter, the current work presents the kinematic and force analyses of the proposed concept along with a series of plots of various mechanism parameters. The variation of these parameters is in good agreement with the physical motion of the devised mechanism. As compared to the conventional methods of tension adjustment, the proposed concept is a better solution for problems that arise due to low manufacturing tolerances and the need for independent tension adjustment in a multi degrees-of-freedom tendon driven RCM mechanism. In the preferred embodiment, it is proposed to use cables (wire-ropes) as tendon elements to drive a mechanically constrained double-parallelogram-based RCM mechanism which is extensively used for Minimally Invasive Surgery. From this implementation, it is learnt that the presented mechanism can be implemented in several configurations. However, this paper presents the preferred embodiment only which meets the demand, of invariant tendon length, of the RCM mechanism under consideration. An initial prototype is made from acrylic sheets, PLA material, and standard elements (like bearings, pulleys, aluminum pins, 0.5 mm stainless-steel wire-rope, etc.) using laser micromachining and 3D printing. [ABSTRACT FROM AUTHOR]

The tacit withdrawal, is one of the abnormal ways of ending the process, instituted since Law 105 of 1890, it has also been called, expiration of the instance or perenniality. The reason behind the decision is the abandonment or inactivity of the process at the request of the party. Article 317 of the General Code of Procedure regulates the procedural act, nefariously sanctioning the litigant, with the extinction of the right sought, when it is decreed a second time between the same parties and in the exercise of the same claims. The consequence falls on the right of action, according to the proportionality study carried out by the Constitutional Court in judgment C-1186 of 2008, which declared the consequence envisaged in law 1194 of 2008 enforceable; judgment that applies to article 317 of the CGP, without, as the judgment warned, the substantial right is lost, what is lost is the right of action. When the intended right is extinguished, the obligation is devoid of action, becoming a natural obligation, at the discretion of the debtor, the procedural action is not a way to decongest the judicial offices, as expressed by the litigants, it is the sanction to their litigation neglected, resulting in the withdrawal of the action, and hence its extinction. Obviously, the tacit withdrawal is an input for decongestion, but it is for the obligation the cause of changing from civil obligation to natural, by not conferring the right to demand its fulfillment. Therefore, in article 1527 of the Civil Code, this new natural obligation must be included. [ABSTRACT FROM AUTHOR]

Springback forecasting of sheet formation is constantly remarkable problem in the métier, due to their influence the great in the definitive shape of the product. Study presents effects of pretension in tow rolling direction (0, 45 degree) on the springback behavior of the (Brass 65-35) sheet under V-die bending by an experimental. The pretension ranges from five different pretensions levels starting from 11% to 55% from total strain in each rolling direction by increment of 11%. used in punching that was performed at a constant deformation velocity of (5 mm/min) then bent on a 90° V-shaped die for the springback evaluation. The results from experiment indicate that the springback increase with pretension ratio and the springback in 45 degree is higher in rolling direction.

In coal mining roadway support design, the working resistance of the rock bolt is the key factor affecting its maximum support load. Effective improvement of the working resistance is of great significance to roadway support. Based on the rock bolt's tensile characteristics and the mining roadway surrounding rock deformation, a mechanical model for calculating the working resistance of the rock bolt was established and solved. Taking the mining roadway of the 17102 (3) working face at the Panji No. 3 Coal Mine of China as a research site, with a quadrilateral section roadway, the influence of pretension and anchorage length on the working resistance of high-strength and ordinary rock bolts in the middle and corner of the roadway is studied. The results show that when the bolt is in the elastic stage, increasing the pretension and anchorage length can effectively improve the working resistance. When the bolt is in the yield and strain-strengthening stages, increasing the pretension and anchorage length cannot effectively improve the working resistance. The influence of pretension and anchorage length on the ordinary and high-strength bolts is similar. The ordinary bolt's working resistance is approximately 25 kN less than that of the high-strength bolt. When pretension and anchorage length are considered separately, the best pretensions of the high-strength bolt in the middle of the roadway side and the roadway corner are 41.55 and 104.26 kN, respectively, and the best anchorage lengths are 1.54 and 2.12 m, respectively. The best anchorage length of the ordinary bolt is the same as that of the high-strength bolt, and the best pretension for the ordinary bolt in the middle of the roadway side and at the roadway corner is 33.51 and 85.12 kN, respectively. The research results can provide a theoretical basis for supporting the design of quadrilateral mining roadways. [ABSTRACT FROM AUTHOR]

In the last 2 decades, many ancillary structures have collapsed, with several instances traceable to loose anchor nuts. According to a quality assurance inspection conducted by the Virginia Department of Transportation (VDOT) in 2012, approximately 30% of the anchor nuts on the inspected ancillary structures across the state of Virginia were found to be loose. The exact cause of the loose anchor nuts is not known; however, one theory is that specified tightening procedures were not properly followed or were not adequate. Currently, a turn-of-the-nut method is used for the tightening of anchor nuts on double-nut moment connections at the base of ancillary structures. This research reviewed current tightening procedures for anchor nuts on ancillary structures. The relationship between three critical tightening parameters—applied torque, nut rotation, and pretension in the rod—was examined. One hundred galvanized steel anchor rods of five different diameters and three different grades were tested. The experimental tests serve as a benchmark to validate the current tightening procedures, as well as to recommend changes. [ABSTRACT FROM AUTHOR]

A quench boiler is the key equipment in ethylene production for the rapid cooling of high-temperature cracking gas. In the boiler, heat transfer is occurs between the hot cracking gas passing through the inner heat exchange tubes with an average temperature of 385 °C and cold water (or boiler water) passing through the inner heat exchange tubes with an average temperature of 350 °C. Required for double-pipe heat transfer, special tubesheets formed by welding flat-round tubes side by side are difficult to design, as no suitable design code is available. The thermal expansion difference between the inner heat exchange tubes and the jacketed tubes could lead to high thermal stress on the tubesheet. In this study, we investigated the effects of pretension or prestretching of the heat exchange tubes on stress distribution and strength assessment of the flat-round tubesheet in a quench boiler under two dangerous load conditions. Results show that without prestretching the heat exchange tubes, the flat-round tubesheet cannot pass the strength assessment. Prestretching the heat exchange tubes is necessary, and a pretension of 9 mm is most suitable. The magnitude of the pretension of the heat exchange tubes should be determined based on the thermal expansion difference between the inner heat exchange tubes and the jacketed tubes, with consideration of the strength improvement of the flat-round tubesheet.

Introduction: Due to the small weight and large flexibility, membrane structures are prone to vibration under external excitation. Furthermore, it may affect the normal function of membrane structures. Objectives: In view of the limitation of traditional perturbation method and small deflection theory in solving strongly nonlinear vibration problem of membranes. an improved multi-scale method is proposed in this paper to investigate the characteristics of strongly nonlinear vibration of membrane. Methods: Firstly, based on the large deflection theory of membrane and the improved multi-scale method, the strongly nonlinear damped vibration control equation of membrane with consideration of geometrical non-linearity is solved. Then, the analytical expressions of the frequency and displacement functions of the strongly nonlinear vibration of membranes are obtained, which are compared with the numerical results. Furthermore, the vibration characteristics of the membrane under the initial displacement are explained together with the experimental results. Results and Conclusion: The results show that the improved multi-scale method is more suitable for solving the strongly nonlinear vibration of membranes than the traditional perturbation method, since the accuracy is higher. Therefore, such a discovery exhibit exposes a more accurate theoretical method for the vibration control and design of membranes. [ABSTRACT FROM AUTHOR]

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The bond performance of a carbon fiber-reinforced polymer (CFRP) tendon in ultra-high performance concrete (UHPC) deteriorates significantly under impact loads. However, the post-impact bond performance, which is crucial for the design and safety assessment of CFRP-UHPC structures after experiencing impact loads, remains unclear. This paper delved into the post-impact bond performance of a CFRP tendon in UHPC through 21 groups of pullout tests, and the influences of the embedded length of the tendon in UHPC, impact height, and initial pretension on the residual bond properties after impact were analyzed. The results show that after exposure to the impact with a higher drop height, the CFRP tendon tended to slide out of UHPC with slighter damages on the tendon surface, and correspondingly, the residual bond strength between the CFRP tendon and UHPC after impact was higher. With the increase in the embedded length of the CFRP tendon in UHPC, the pullout capacity increased and the constraining effect of the external steel barrel to the inside CFRP tendon and UHPC improved, which resulted in a higher residual bond strength. A higher initial pretension induced more pronounced shear damage and abrasion on the CFRP ribs, therefore, weakening the remaining resistance to pullout tension after impact. Finally, prediction formulas for the residual bond strength of a CFRP tendon with different embedded lengths and pretension in UHPC, following impacts at various strain rates, were developed. • The post-impact bond performance of a CFRP tendon in UHPC was investigated. • The residual bond strength between the CFRP tendon and UHPC was enhanced with the increase in the embedded length and the height of the impact, but it diminished with a reduction in the initial pretension. • Prediction formulas for the residual bond strength of a CFRP tendon in UHPC after impact were developed. [ABSTRACT FROM AUTHOR]

Abstract Although pretensioned concrete structures have increasingly been used worldwide, a number of design issues need to be addressed to further improve the structural performance. Transfer length of pretensioned members was investigated with several test variables in this study by adopting various sensing technologies including the Smart Strands with embedded fiber optic sensors. The effect of increased strength in 2360 MPa high-strength strand on the transfer length was also analyzed. Representative provisions widely used in design were compared with the test results for consistency and appropriate conservatism. The strain distribution required for the transfer length depended partly on the type and location of sensors, which suggests the challenges associated with reasonable determination of the transfer length. According to the results of the analysis, the predictive equation in ACI 318 was relatively accurate and conservative under various conditions including high-strength strands. However, the transfer lengths based on the strand strains rather than the conventional surface strains of concrete require further investigation depending on the bonding behavior between the strand and the surrounding concrete inside a member. Thus, this study also introduces a new sensing technology utilizing the Smart Strand to reliably measure the strain distribution along a strand.

Abstract Background Pretension of the viscoelastic graft by cyclic knee motion has been confirmed to decrease the graft creep and improve the outcome of anterior cruciate ligament (ACL) reconstruction. The purpose of the present study was to investigate the effect of cyclic knee motion on the elongation of the four-strand hamstring tendon autograft in situ and to explore the stable level cycle, in which the tendon length achieved a stable level. Methods The study was performed with 53 consecutive patients undergoing transtibial ACL reconstruction with four strand hamstring tendon from Aug 2013 to Apr 2015. 43 males and 10 females were included with mean age of 29 ± 10 years. The pretension of the tendons was operated by cyclical knee motion ranging from 0 to 110°after the femoral fixation with Endo-button. The tendon length after 10, 20, 30 and 40 cycles was measured respectively and compared by repeated measure ANOVA. Then multivariate logistic regression was used to investigate the effect of the patients’ parameters (age, gender, height, body weight, tendon length, etc.) on the elongation of the graft and the stable level cycle. Results The mean lengthening of the graft at 10, 20, 30 and 40 times was 3.0 ± 1.4 mm, 4.3 ± 1.5 mm, 4.8 ± 1.7 mm and 4.8 ± 1.8 mm respectively. No significant correlation was found between the elongation and the patients’ parameters. There was significant difference of the tendon length from 0 to 30 cycles (F = 264.8, df = 1.95, p

Bolt preload is a critical parameter in bolted connections with a strong influence on their general structural behavior. Traditional bolt preload estimation methods are sensitive to the surface conditions of the fastening elements while more accurate measuring methods might require significant modifications of the connection, such as embedded sensors. In this study, a novel contactless bolt preload monitoring method based on Digital Image Correlation measurements of the bolt elongation was developed. A fixed bolted setup was designed to validate the optical measurements with laser triangulation and three-dimensional point tracking, while the bolt preload was monitored with an embedded load cell. Two M16 bolt classes, 8.8 and 10.9, and multiple bolt lengths were evaluated. The bolt preload and displacement results correlated well with the available bolt theoretical models and an accurate preload estimation was possible. An analysis on the method resolution demonstrates that better resolutions are achieved with slender and long bolts. The method resolution is estimated to be under 2.25% and 1.8% of the recommended bolt preload value for each bolt class, respectively. [ABSTRACT FROM AUTHOR]

Bolted connections are used all over the world in almost every engineering application. It is an established fact that these joints get loosened when subjected to dynamic loadings. The objective of this paper is to develop an experimental setup to investigate loosening of bolted joints and its analytical study for establishing the role of the washer subjected to dynamic loading. Experiments were carried out over bolted joint subjected to shear loading with various test variables, including pretension/torque values ranging from 20 N-m, 22.5 N-m and 25 N-m, and number of load cycles ranging from 30,000 to 300,000 cycles. Several tests as per DOE were performed. These tests were carried out following 3 washer conditions: NW-No Washer; PW-Plain Washer; and SW-Spring Washer. The results were represented in terms of slackening/loosening angle with respect to torque/pretension and load cycles. A mathematical model is also developed between angle of loosening, load cycle and pretension. Analysis of this test was performed; contour and surface plots were analyzed. A new mathematical equation was proposed and validated based on the experimental outcomes. The study concludes that washers play a very vital role in preventing loosening failures of bolted joints. [ABSTRACT FROM AUTHOR]

Documented evidence shows that anchor nut loosening on highway ancillary structures has been a problem in the transportation industry since at least the 1990s. There have been reported cases in the past, where loose anchor nuts were found to be partially responsible for the failure of ancillary structures. Resonant vibrations in ancillary structures as a result of variable frequency winds are believed to be one of the potential causes of loose anchor nuts. The current research primarily focused on investigating the effect of wind-induced vibrations on the loosening of anchor nuts in double-nut moment connections in ancillary structures. The research involved large-scale vibration testing of a traffic signal on the basis of vibration stress results from a 4-month field monitoring program. The purpose of the large-scale testing was to establish the relationship between the number of vibratory cycles, rod pretension, and nut loosening. A small-scale vibration test was also performed to validate the large-scale testing results. The testing results showed that anchor rods tightened in a double-nut moment connection above a pretension of 38 MPa (5.5 Ksi) do not experience nut loosening under vibrations. [ABSTRACT FROM AUTHOR]

This paper presents with an effective and fast approach to the optimization of the pretension forces in arched bridges with suspended deck, which makes use of the influence matrix method (IMM). The given cable-tensioning procedure leads to a linear system of equations with a reduced number of unknowns and can be effectively implemented within active control procedures that handle time-varying loading conditions. This method produces a target bending moment distribution (TBMD) over the structure, which significantly mitigates the state of stress of the deck. Numerical simulations referred to a Nielsen arch bridge illustrate the versatility of the proposed approach when dealing with different loading conditions.

This paper is focused on the effect of initial pretension on the dynamic bond performance of the anchorage under impact loads. Drop-weight impact tests were conducted on 15 groups of specimens with four embedded lengths and various pretension ratios; the effects of pretension and embedded length on the bond strength and slip of the anchorage are discussed in the paper. The test results show that a higher pretension ratio led to severer surface damage on the CFRP tendons. With the increase of the pretension ratio, the mechanical interlocking between CFRP ribs and UHPC was improved, leading to an increased average bond strength. By contrast, the relatively large shear deformation and severe damage of CFRP ribs induced by pretension formed "initial defects", which resulted in a lower residual bond performance during impact loading. Based on the test results, a pretension ratio-dependent strength retention function was proposed to quantify the shear damage effect of CFRP ribs caused by pretension; by incorporating this function, accurate formulas were developed for determining the dynamic bond strength of a pretensioned anchorage. • Drop-weight impact tests were conducted on UHPC-filled bond-type anchorages for CFRP tendons under different initial pretensions. • The initial pretension enhanced the mechanical interlocking between CFRP ribs and UHPC, which led to an improved dynamic bond strength of the anchorage. • Accurate formulas were developed for determining the dynamic bond strength of a pretensioned anchorage. [ABSTRACT FROM AUTHOR]

En el presente artículo se cuestiona el uso que en derecho colombiano tradicionalmente se le ha dado al vocablo acción, demostrando para ello, el error conceptual que de tiempo atrás se ha venido afianzando, y que suele tener profundas consecuencias en la vida práctica, especialmente evidentes en el sacrificio de los derechos sustanciales de las partes que acuden a la administración de justicia, en espera de una solución a sus conflictos y se encuentran por el contrario, con el riesgo latente de ver truncadas sus reclamaciones debido a la supuesta escogencia errónea de la acción.

In a not very well known essay, Hans Reiner claims that there are two main theories which have considered the phenomenon of moral obligation: on the one hand, the theory which acknowledges the validity of such phenomenon and tries to found it either on the religiousmetaphysical presupposition of the faith in God an on His commandments or in the metaphysics of an “ontological structure” or “essence” of human being; on the other hand, the theories which deny the character of original phenomenon to obligation. This kind of theories offer just a geneticcausal analysis of obligation. Phenomenological method would appear, according to Reiner, as a “third way”. The aim of this paper is to criticize this last statement by Reiner and offer a general view of the main elements of this method which can be especially relevant for Philosophy of Law.

Viewing both ethics and aesthetics as reflections of the social, cultural sociologists fail to thoroughly account for the complex interrelations between these realms. This article explores this relationship through a study of 'farterism', a discursive category that emerged in Israel during the 1990s and is used to denounce vain pretence. Not only do aesthetic surfaces operate as emotionally-laden shortcuts to deeper layers of ethical meaning, the very act of aesthetic judgement is moralized, subjected to normative regulation. The article analyses the use of 'farterism' in the lay evaluation of architecture, restaurants and films, while reconstructing its implied ethic of aesthetic, 'the hedonistic ethic of authenticity'. I discuss this ethic's philosophical-cultural roots (including the performative contribution of critical social science) and the continuities between its application in cultural evaluation and in wider moral contexts. The pattern that emerges in the data relies on the Emperor's New Clothes tale: uncovering the hidden influence of the social on the aesthetic is at the centre of the normative regulation of aesthetic judgement. This allows laypersons to challenge cultural hierarchies shaped by cultural fields, experts and markets, and denounce them as corrupted by the social. [ABSTRACT FROM AUTHOR]