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1
Zhang, Yisheng, Jiangfei Wang, Qi Zhou, Yingchun Cai i Wei Tang. "The Investigation of Local Scour around Bridge Piers with the Protection of a Quasi-Stumps Group". Water 15, nr 15 (7.08.2023): 2858. http://dx.doi.org/10.3390/w15152858.
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In this study, a quasi-stumps group structure was proposed and placed upstream of the bridge piers to mitigate the scour of the waterflow on the riverbed. Both experiment and numerical simulations using FLOW 3D were employed to study the protective effect of this structure. The numerical results were in good agreement with the experimental findings. It was found that the quasi-stumps group can effectively reduce the flow velocities around the bridge piers, thereby promoting the deposition of suspended sediment. As a result, there was no erosion around the piers, and instead, siltation was formed, which contributed to the stability of the piers. The deposition height around the piers increased as the L (the horizontal distance between the quasi-stumps group and the piers) decreased and both the P (the height of the quasi-stumps group) and S (the ratio of the area of a single leaf on the quasi-stumps group to the cross-sectional area of a single pier) increased. As the L, P, and S increased, the quantity of suspended sediment deposition over the entire riverbed increased. The optimal combination of the quasi-stumps group’s protective effect was determined to be L = D (pier diameter), P = H (water depth), and S = 0.148.
2
Hassan, Zahraa F., Ibtisam R. Karim i Abdul-Hassan K. Al-Shukur. "Effect of Interaction between Bridge Piers on Local Scouring in Cohesive Soils". Civil Engineering Journal 6, nr 4 (1.04.2020): 659–69. http://dx.doi.org/10.28991/cej-2020-03091498.
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Local scour at the piers is one of the main reasons of bridge foundation undermining. Earlier research studies focused mainly on the scour at a single bridge pier; nevertheless, modern designs of the bridges comprise wide-span and thus group of piers rather than a single pier are usually used to support the superstructure. The flow and scour pattern around group of piers is different from the case of a single pier due to the interaction effect. Reviewing the literature of local scour around bridge piers group revealed that the local scour around bridge piers group founded in cohesive soil bed was not investigated, and most of the scour studies were related to scour in cohesionless soils. The objective of the present study is to investigate the effect of the interaction between two in-line (tandem) circular bridge piers of variable spacings founded in cohesive soil on the local scour. A set of laboratory flume experiments were conducted under the clear-water scour condition to investigate this effect. This study is the first that investigates experimentally the scour around group of bridge piers in cohesive bed. It was found that the maximum scour depth at the upstream pier of the two in-line piers occurred at a spacing of two times the diameter of the pier, scour at the downstream pier was reduced due to a sheltering effect, the interference effect will be reduced for pier spacings larger than three times of the pier diameter. A recent pier scour equation was used to estimate the scour depths at the two in-line piers in cohesive soil and compare the estimated value with the measured scour depths in the laboratory. The comparison indicated that the proposed scour equation overestimates the scour depths at both the upstream and the downstream pier.
3
Lakusic, Stjepan. "Simulation of Scour at Bridge Supports". Journal of the Croatian Association of Civil Engineers 72, nr 09 (październik 2020): 793–801. http://dx.doi.org/10.14256/jce.2506.2018.
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Groups of piers are used on bridges to minimise scour around bridge supports. The prediction of scour around piers due to interaction of vortices around bridge piers is more complex compared to scour prediction around a single pier. Four arrangements of bridge piers with different spaces in the lateral and longitudinal directions are investigated under clear water conditions to observe scour generation around bridge foundations. The experimental study is performed in a rectangular open channel. A 3D numerical study based on fluid dynamics is also conducted. Results show that different pier group arrangements produce smaller scour holes than a single pier.
4
Daneshfaraz, Rasoul, Amir Ghaderi, Maryam Sattariyan, Babak Alinejad, Mahdi Majedi Asl i Silvia Di Francesco. "Investigation of Local Scouring around Hydrodynamic and Circular Pile Groups under the Influence of River Material Harvesting Pits". Water 13, nr 16 (11.08.2021): 2192. http://dx.doi.org/10.3390/w13162192.
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Mining activities can endanger the stability of hydraulic structures. Numerical modeling of local scouring around hydrodynamic and circular bridge pile groups, due to the action of clear water conditions via non-cohesive sediment, was performed using a computational fluid dynamics (CFD) model, a large eddy simulation (LES) turbulence model, and a van Rijn sedimentary model with FLOW-3D software. The pile groups were positioned upstream and downstream of a sand mining pit. The results showed that the scour depth around the downstream pile group was greater than that of the upstream one. Using hydrodynamic piers reduced the scour depth upstream of all piers and the material harvesting pit. The maximum reduction in scour depth was observed in front of the fifth pier, with a 29% reduction in scour depth. Additionally, for all models, as the material harvesting pit was moved downstream, the downstream turbulence was enhanced and stronger flow reversal and horseshoe vortices were detected in from of the downstream pile group. The flow patterns around the pile group showed that the presence of hydrodynamic piers in the upstream pile group leads to a decrease in the maximum flow velocity, whereas, when such piers were positioned in the downstream pile group, the velocity increases.
5
Rashno, Emad, Amir Reza Zarrati i Mojtaba Karimaei Tabarestani. "Design of riprap for bridge pier groups". Canadian Journal of Civil Engineering 47, nr 5 (maj 2020): 516–22. http://dx.doi.org/10.1139/cjce-2019-0007.
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Stable riprap size and optimized extension of the riprap layer around double and triple piers along the flow direction are studied experimentally. Results showed that the critical riprap failure area and stable riprap size around the first pier remain unchanged with increasing pier spacing. In addition, the largest stable riprap should always be placed in front of the first pier in comparison with the remaining downstream piers. However, by increasing the pier spacing, stable riprap size around the second and third pier increased and approached that around the first pier. A relationship was developed for designing stable riprap size in pier groups. Based on this relationship, different riprap sizes are suggested for different zones around the pier group. Experiments showed that the critical zone around the piers includes only a small area and the rest of the riprap extent area can be protected with smaller riprap stones.
6
Yuksel, Yalcin, Yesim Celikoglu i Elif Sen. "Propeller jet flow scour around pile group supported piers". Ocean Engineering 239 (listopad 2021): 109889. http://dx.doi.org/10.1016/j.oceaneng.2021.109889.
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Chen, Hsin Hung, Ray-Yeng Yang, Ping-Chiao Kuo i Hwung-Hweng Hwung. "PHYSICAL MODELING STUDY ON SCOUR AND SCOUR COUNTERMEASURE FOR SEA-CROSSING BRIDGE PIERS". Coastal Engineering Proceedings 1, nr 33 (25.10.2012): 83. http://dx.doi.org/10.9753/icce.v33.sediment.83.
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There are significant engineering challenges in placing the sea-crossing bridge piers in more or les shallow coastal waters because, as well as having to withstand storm-force waves and tidal currents, the bridge piers have to remain stable on a sea bed that may be continuously changing. One of the major challenges faced by designers is how to predict, and prevent, scour of the seabed sediments around the sea-crossing bridge piers. This paper describes a physical model study on scour and scour countermeasure for sea-crossing bridge piers. A 1:49 scale movable bed model tests were carried out in the Near-shore Wave Basin (NSWB, 27m x 19m) at the Tainan Hydraulics Laboratory, National Chang Kung University (NCKU), Tainan, Taiwan, with the sea-crossing bridge piers in the test area. Three series of physical model tests were performed in this study. The aim of the first test series is to investigate the maximum scour depth for the initial construction of bridge piers with only one pier model. Then the second test series were conducted to investigate the greatest magnitude of local scour and potential scour area in the sand bed around the sea-crossing bridge group piers with no scour protection. Based on the analysis from the former NSWB experimental results, the suitable scour countermeasure for sea-crossing bridge piers would be proposed and validated its function of preventing scour in the third test series.
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Pagliosa, Paulo Roberto, Mauricio Cantor, Fernando Scherner, Mariana Beatriz Paz Otegui, Aurea Luiza Lemes-Silva, Cintia Dalcuche Leal Martins, Giorgia Freitas Alves, Alessandra Fonseca i Paulo Antunes Horta Jr. "Influence of piers on functional groups of benthic primary producers and consumers in the channel of a subtropical coastal lagoon". Brazilian Journal of Oceanography 60, nr 1 (marzec 2012): 65–73. http://dx.doi.org/10.1590/s1679-87592012000100007.
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Artificial habitats have become common in coastal areas worldwide and may influence the structure and functioning of benthic ecosystems. We analyze the influence of piers on the benthic morphofunctional groups of rocky seaweeds and of soft bottom macrofauna in the channel of Conceição Lagoon (southern Brazil). The main impact is a reduction in the luminosity available for photosynthetic activity which is directly related to a decrease in the biomasses of sediment microphytobenthos and of more highly structured macroalgae life-forms. Contrary to expectations, the morphotypes of potentially high biomass productivity, such as articulated coralline, corticated and leathery macroalgae, were in general less abundant and the low biomass foliose and filamentous macroalgae occurred in reference areas but not under the piers. The piers' effects on motile epifauna and infauna functional groups were site-specific and probably related to the general reduction in primary producer organisms in the new habitats. The discretely motile infauna was the only functional group able to thrive under the piers due to their reduced motility and fragile morphological structures, being benefited by the shelter provided by the artificial habitats. Our results showed that the piers might have a negative effect on the base-trophic level organisms responsible for bottom-up controls.
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Shi, Liang Hong, Chuan Bao Feng, Tong Gang Zhang, Shang Dian Sha, You Wei Su, Sheng Wei Du i Gang Zhu. "Deformation Monitoring of Railway Bridge Group Influenced by Construction of Metro Tunnel". Applied Mechanics and Materials 405-408 (wrzesień 2013): 1810–14. http://dx.doi.org/10.4028/www.scientific.net/amm.405-408.1810.
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With the development of the high-speed railway (HSR) and metro, the metro crossing the HSR in operation usually happened in metropolis. Considering the stability of railway bridge foundation is very critical to the safety of HSR in operation, it is very important to monitor the influence of the construction of metro tunnel. The no.6 metro line of Nanjing city is crossing the railway bridge group, including three HSR lines, Beijing-Shanghai HSR, Nanjing-Anqing intercity railway, and Shanghai-Wuhan-Chengdu railway. A real-time deformation system using sensors with high accuracy and wireless network is designed to monitor the bridge piers, which are adjacent to the metro tunnel and may be affected in the bridge group. The tilt and settlement of bridge piers and horizontal displacement of pier head are considered in this system. The monitoring results show the feasibility of the system and grantee the operation and bridge engineerings safety.
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Rahimi, Ebrahim, Kourosh Qaderi, Majid Rahimpour i Mohammad Mehdi Ahmadi. "Effect of Debris on Piers Group Scour: An Experimental Study". KSCE Journal of Civil Engineering 22, nr 4 (kwiecień 2018): 1496–505. http://dx.doi.org/10.1007/s12205-017-2002-y.
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Puricelli, Martín, Pablo Spalletti i Agnes Paterson. "Estudio de erosión local en grupos de Pilas Cuadradas". Aqua-LAC 6, nr 1 (31.03.2014): 25–32. http://dx.doi.org/10.29104/phi-aqualac/2014-v6-1-04.
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Con el objeto de realizar experiencias relativas a la erosión local en grupo de pilas, para los casos menos estudiados pero de aplicación práctica, se trabajó con dos pilas de sección cuadrada. Se realizaron ensayos a fondo móvil en un canal de dos metros de ancho en condiciones de agua clara, sin transporte de sedimento aguas arriba de estas estructuras para evitar las complejidades propias de las formas de fondo. Se exploraron una variedad de condiciones experimentales con diferentes tirantes (entre 30 y 50 cm), espaciamiento entre pilas y la configuración de las mismas. Las pilas tienen 20 cm de lado. En un caso, ambas pilas están alineadas a la corriente y en el segundo caso que denominamos al tresbolillo, las pilas están desplazadas lateralmente una respecto de la otra. En este trabajo se analizan las erosiones máximas medidas, el campo de velocidades alrededor de las pilas y el relevamiento batimétrico del lecho del canal. Las erosiones máximas medidas se compararon con diferentes fórmulas de predicción. Se estudió la evolución temporal de la erosión comparándola con ensayos similares de larga duración pero con una única pila, analizándose también el ajuste de formulaciones predictivas del avance de la socavación en el tiempo. En todos los casos se observó una dependencia de la erosión máxima respecto de la separación entre pilas para los grupos de pilas alineadas. Esta erosión es sobreestimada con la fórmula del HEC-18 para la geometría en tresbolillo. Estos efectos de conjunto para las pilas alineadas se manifiestan desde los primeros minutos de las experiencias. Para la geometría en tresbolillo se observó un cambio en la curvatura de la evolución temporal de la erosión que se puede asociar justamente a estos efectos de conjunto.
12
Chreties, Christian, Luis Teixeira i Gonzalo Simarro. "Pile Group Protection with Riprap Mattress". Advances in Civil Engineering 2012 (2012): 1–7. http://dx.doi.org/10.1155/2012/693506.
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New experimental data on plan dimensions for riprap mattresses used in pile group protection against edge failure are analyzed. The influence of flow conditions and the distance between piles in plan dimensions of riprap mattresses are addressed. An alternative methodology for the experimental study of edge failure in pile groups is proposed and verified, significantly reducing the duration of tests (from several days to a few hours) and yielding similar results. For the pile group configuration tested, a design expression for minimum riprap width is obtained. The influence of the distance between the piles on the width of riprap dimensions is shown to be small, and the proposed expression compares well with some of the expressions for single piers found in the literature.
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Chaiprasert, Thanawat, Yujia Liu, Nobuhiro Takeda i Masafumi Unno. "Vinyl-Functionalized Janus Ring Siloxane: Potential Precursors to Hybrid Functional Materials". Materials 14, nr 8 (16.04.2021): 2014. http://dx.doi.org/10.3390/ma14082014.
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A vinyl-functionalized all-cis-tetrasiloxycyclotetrasiloxane [ViSi(OSiMe2H)O]4 (Vi = vinyl group) Janus precursor was prepared from potassium cyclotetrasiloxane silanolate. The Janus precursor was selectively modified at its dimethylhydrosilyl groups [–SiMe2H] via the Piers–Rubinsztajn reaction to obtain a family of new tetravinyl-substituted Janus rings [ViSi(OR’)O]4 containing various functional groups in moderate yields. Remarkably, the tetravinyl groups on the structure remained intact after modification by the Piers–Rubinsztajn reaction. Since these synthesized compounds possess multiple functional groups (up to eight per molecule), they are potential precursors for advanced hybrid organic-inorganic functional materials.
14
Najafzadeh, Mohammad, i Hazi Mohammad Azamathulla. "Group method of data handling to predict scour depth around bridge piers". Neural Computing and Applications 23, nr 7-8 (21.09.2012): 2107–12. http://dx.doi.org/10.1007/s00521-012-1160-6.
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Rahul, M., i S. Baldev. "Prediction of scour depth around bridge piers in tandem arrangement using M5 and ANN regression models". Archives of Materials Science and Engineering 2, nr 102 (1.04.2020): 49–58. http://dx.doi.org/10.5604/01.3001.0014.1524.
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Purpose: Due to an increase in a number of bridges being constructed, scour depth around bridge piers is gradually being recognized as one of the possible reasons for bridge failure. According to [1] about 53% of bridge failures in the US were caused due to floods and corresponding scour in the rivers. Lots of work has been carried out around the single pier but in the case of group piers, the work is very less. Hence, it becomes necessary to calculate the actual scour depth around the bridge piers considering the close location of bridges as well. Design/methodology/approach: Recognizing the need for research in this direction, an experimental study was planned and conducted in the Hydraulics Laboratory of Civil Engineering Department of National Institute of Technology Kurukshetra, India. Experiments were conducted in a standard recirculating tilting bed water flume 15 m long, 0.4 m wide, and 0.60 m deep. The orientation of more than one pier, namely Tandem pattern was employed for the work. Two pier models, 62 mm and 42 mm diameter were used for the experimental study. The mobile bed used in the experiments had an average mean size, d50 = 0.23 mm, 0.30 mm and 0.50 mm. Findings: The outcomes of the ANN function and M5 model analysis have been used to compare with experimental results. From the earlier studies, it was concluded that, when the clear spacing between the pier models was greater than 0D the scour depth around the piers increase with a rapid rate. However, in the case of modelling techniques, M5 models show higher predictive accuracy than ANN models. Research limitations/implications: It is a significant area of research. However, the present study has been a time and facility- constrained study. Therefore, there is a large scope to conduct further studies on the subject, Different pattern i.e. Side by Side; Staggered and Group of piers can be adopted for further investigations. Originality/value: Sufficient work has been done by number of researchers around the single bridge pier. But due to rapid urbanization a number of bridges constructed in close proximity to each other which affects the scour depth of each other. Modelling techniques used in hydraulic engineering are not always effective in practice. The present study discusses the effect of spacing on scouring around piers in a tandem arrangement using experimental as well as modelling techniques. To predict the scour depth of the Tandem arrangement 89 laboratory data sets have been used.
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Hidden, Scott, i Nariman Abar. "Predesign Foundation Load Test Program for US-17 (Wilmington) Bypass over Northeast Cape Fear River". Transportation Research Record: Journal of the Transportation Research Board 1736, nr 1 (styczeń 2000): 19–23. http://dx.doi.org/10.3141/1736-03.
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The North Carolina Department of Transportation is currently conducting a predesign foundation load test for a new bridge over the Northeast Cape Fear River near Wilmington, North Carolina. The primary purpose of the load test program is to determine whether concrete piles can penetrate a very dense and cemented sand layer and what side friction and tip bearing capacities should be used for the design of the drilled piers. Significant cost savings could be realized if pile foundations instead of drilled piers could support the approach spans of the bridge. For this determination, three concrete piles will be installed 30 m into the ground. Significant cost savings could also be realized by making a more accurate determination of the drilled pier capacities. For this determination, the side friction and tip bearing capacities of the dense Peedee sands and the underlying hard marine clays will be determined with Osterberg cell tests on two 2130-mm-diameter drilled piers. The different subsurface layers (muck, alluvial sands, and Peedee sands) will also be tested laterally with both static and statnamic testing to assist in the foundation design. The load test program incorporates an NCHRP research program on pile groups. The program includes testing a reusable instrumented steel pile group and frame at various sites in various soil conditions around the United States. The load test program results to date, the effect of the results on the foundation design, and the construction, testing, and instrumentation of the drilled piers are described.
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Hamilton, J. S. "Piers Gaveston and the Royal Treasure". Albion 23, nr 2 (1991): 201–7. http://dx.doi.org/10.2307/4050602.
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Many charges were leveled against Piers Gaveston, the Gascon favorite of Edward II and earl of Cornwall from 1307 until his violent death at the hands of a group of disaffected magnates led by earls Thomas of Lancaster and Guy of Warwick in 1312. One of the most readily accepted has been the accusation that he had maliciously and illegally taken the royal treasure into his own hands and that he had then transported the treasure to his native Gascony. According to the contemporary Annales Londonienses, no sooner had Gaveston been recalled from exile than Edward bestowed the royal treasure upon him in its entirety: “Furthermore he has relinquished to the said Piers the disposition and control of all the royal treasure, jewels, and precious stones.” Other chronicles refer to Gaveston's acquisition of the royal treasure in 1307, linking it to the fall from grace of Edward I's former treasurer, Walter Langton, bishop of Coventry and Lichfield (but most often styled bishop of Chester in contemporary accounts of the reign). According to the Annales Paulini, Gaveston, still not satisfied, induced Edward to give him the wedding gifts that the king had received from his new father-in-law, Philip the Fair of France. Moreover, the earl of Cornwall was supposed to have sent this treasure abroad resulting in the pauperization of both king and Crown. To the monastic chroniclers of the fourteenth century, and indeed to the magnates who drafted the Ordinances of 1311, the veracity of these allegations was too well established to require specific proof. Modern scholars, however, require more concrete evidence than the narrative sources supply of Gaveston's alleged wrongdoing. Documentary evidence sheds light upon the various questions revolving around Piers Gaveston and the royal treasure.
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Zhao, Dong Xiao, Jun Jie Wang i Jun Sheng Su. "Seismic Response Analysis of Deep Water Bridges with Pile Group Foundations". Applied Mechanics and Materials 580-583 (lipiec 2014): 1494–98. http://dx.doi.org/10.4028/www.scientific.net/amm.580-583.1494.
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In this paper, we intended to replace the fluid-structure interaction of deep water bridge piers with acceleration-dependent forces during an earthquake. The hydrodynamic pressure on bridge pier groups under seismic excitation is studied using the finite volume method. Different seismic waves with various spectrum components are selected in order to cover frequently encountered cases. The calculated forces of these cylinders are fitted into the Morison equation, and by calculation, the drag force term is negligible, thus the effect of fluid is converted into one added mass term. The paper further calculated the dynamic response of a continuous beam bridge with pier groups in water to check the validity of our proposed method.
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Alexopoulos, Demetrios S., i Evangelia Foudoulaki. "Construct Validity of the Piers-Harris Children's Self-Concept Scale". Psychological Reports 91, nr 3 (grudzień 2002): 827–38. http://dx.doi.org/10.2466/pr0.2002.91.3.827.
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The aim of the present study was to investigate the construct validity of the Piers-Harris Children's Self-concept Scale with a group of 511 (264 girls, 247 boys aged 9 to 12 years) Greek children. Principal Components Analysis was performed. Six factors emerged, i.e., Behavior, Anxiety, Intellectual and School Status, Popularity, Physical Appearance and Attributes, and Self-contentment.
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Zeng, Yong, Xuan He, Yongqi Li i Jianting Zhou. "Assessment of Modal Characteristics of Steel–Concrete Composite Girder Bridge with V-Shaped Piers". Applied Sciences 13, nr 6 (8.03.2023): 3421. http://dx.doi.org/10.3390/app13063421.
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As the standards of bridge design and construction continue to improve, more and more combination bridges are being put into use. The public’s demand for aesthetically pleasing bridges is also increasing, making it necessary to use the special structure of steel–concrete combinations, continuous V-shaped piers, and continuously stiffened bridges. This structure has the structural and mechanical characteristics of both a continuous girder and a V-shaped pier bridge. The span can be reduced to a certain extent because the support of the V-shaped piers can be applied directly to the main girder. The spanning capacity of the bridge is generally greater than that of a combined steel–concrete girder bridge with vertical piers. The whole bridge is continuous, without expansion joints, making it more stable and safe for traffic. At present, research on this structural bridge type is not yet complete. In this paper, the structural system and dynamic characteristics of this bridge are investigated in the context of real-life engineering. Firstly, the self-vibration characteristics of the three structures were analyzed, and their effects on the self-vibration characteristics were studied by varying the height of the crossbeam at the V-shaped piers’ support, the main beam stiffness, and the V-shaped piers’ stiffness in the three structures. The results show that the increase in main beam stiffness can effectively improve the vertical stiffness of the three structures, with the most obvious effect on structure one and the least effect on structure two; the increase in V-shaped pier stiffness causes a huge improvement in the transverse stiffness of the three structures. Subsequently, a two-unit rod system model of the background bridge was established using the finite element method, and the original model was improved by calculating the equivalent shear stiffness of the shear nail group so that it could simulate the shear joints more accurately. The effects of the shear connectors on the self-vibration characteristics of the steel–concrete combined continuous beam–V-shaped piers and continuous rigid-frame bridge were investigated through theoretical analysis and finite element simulation. It was found that due to the existence of flexible shear connectors, the interface between the steel beam and concrete slab in the combined beam has a slippage effect which causes the deformation to become unsynchronized, and there is a certain difference between vibration patterns. The stiffness of the shear connectors has a certain effect on the self-vibration frequency of the bridge. The damage to the local shear connectors does not have a large effect on the self-vibration frequency of the overall structure, but the damage to the shear connectors at the beginning of the connection between the V-shaped piers and the main beam is greater than that of the other areas. Damage to shear joints should be given special consideration in comparison to other areas.
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Fritz-Langhals, Elke. "Main Group Catalysis: Cationic Si(II) and Ge(II) Compounds as Catalysts in Organosilicon Chemistry". Reactions 2, nr 4 (19.10.2021): 442–56. http://dx.doi.org/10.3390/reactions2040028.
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Cyclopentadienyl (Cp)-coordinated cationic Si(II) (1) and Ge(II) compounds (2) are a new class of catalysts for various transformations in organosilicon chemistry. This review demonstrates that these compounds effectively catalyze technically important reactions, such as the hydrosilylation of carbon-carbon multiple bonds and various types of siloxane-coupling reactions, e.g., the Piers-Rubinsztajn reaction and the oxidative siloxane coupling reaction. Whereas the cationic Si(II) compounds are sensitive to air and moisture, the corresponding cationic Ge(II) compounds are bench stable, thus offering further advantages. The new catalysts contribute to the growing need for the substitution of transition metals and heavier main group metals by their lighter congeners, especially in industrially relevant organosilicon chemistry.
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Ghodsi, Habibeh, i Mohammad Javad Khanjani. "Application of Improved GMDH Models to Predict Local Scour Depth at Complex Bridge Piers". Civil Engineering Journal 6, nr 1 (1.01.2020): 69–84. http://dx.doi.org/10.28991/cej-2020-03091454.
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Scour depth prediction is a vital issue in bridge pier design. Recently, good progress has been made in the development of artificial intelligence (AI) to predict scour depth around hydraulic structures base such as bridge piers. In this study, two hybrid intelligence models based on combination of group method of data handling (GMDH) with harmony search algorithm (HS) and shuffled complex evolution (SCE) have been developed to predict local scour depth around complex bridge piers using 82 laboratory data measured by authors and 615 data points from published literature. The results were compared to conventional GMDH models with two kinds of transfer functions called GMDH1 and GMDH2. Based upon the pile cap location, data points were divided into three categories. The performance of all utilized models was evaluated by the statistical criteria of R, RMSE, MAPE, BIAS, and SI. Performances of developed models were evaluated by experimental data points collected in laboratory experiments, together with commonly empirical equations. The results showed that GMDH2SCE was the superior model in terms of all statistical criteria in training when the pile cap was above the initial bed level and completely buried pile cap. For a partially-buried pile cap, GMDH1SCE offered the best performance. Among empirical equations, HEC-18 produced relatively good performances for different types of complex piers. This study recommends hybrid GMDH models, as powerful tools in complex bridge pier scour depth prediction.
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Sharafati, Ahmad, Ali Tafarojnoruz i Zaher Mundher Yaseen. "New stochastic modeling strategy on the prediction enhancement of pier scour depth in cohesive bed materials". Journal of Hydroinformatics 22, nr 3 (3.02.2020): 457–72. http://dx.doi.org/10.2166/hydro.2020.047.
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Abstract Scouring around the piers, especially in cohesive bed materials, is a fully stochastic phenomenon and a reliable prediction of scour depth is still a challenging concern for bridge designers. This study introduces a new stochastic model based on the integration of Group Method of Data Handling (GMDH) and Generalized Likelihood Uncertainty Estimation (GLUE) to predict scour depth around piers in cohesive soils. The GLUE approach is developed to estimate the related parameters whereas the GMDH model is used for the prediction target. To assess the adequacy of the GMDH-GLUE model, the conventional GMDH and genetic programming (GP) models are also developed for evaluation. Several statistical performance indicators are computed over both the training and testing phases for the prediction accuracy validation. Based on the attained numerical indicators, the proposed GMDH-GLUE model revealed better predictability performance of pier scour depth against the benchmark models as well as several gathered literature studies. To provide an informative comparison among the proposed techniques (i.e. GMDH-GLUE, GMDH, and GP models), an improvement index () is employed. Results indicated that the GMDH-GLUE model achieved = 6% and = 3%, demonstrating satisfying performance improvement in comparison with the previously proposed GMDH model.
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Gao, Pengcheng, Xianyou Mou i Honglan Ji. "Simulation Study on Local Scour Characteristics of Tandem Bridge Piers in a Straight River under a Changing Environment". Sustainability 15, nr 15 (31.07.2023): 11776. http://dx.doi.org/10.3390/su151511776.
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Hydrodynamics is a common manifestation that causes natural scouring of riverbeds, and it is one of the factors that exacerbate the natural disasters of local scouring of bridge piers, causing sustainability of environmental changes in the water. The evolution pattern and scour characteristics of the bed surface around the submerged structures under different scouring conditions vary greatly. In order to investigate the scour mechanism, the reformed group (RNG) turbulence model in computational fluid dynamics (CFD) simulation software (v11.2) was used to simulate the scour under the clear-water scour and live-bed scour environments, and different scour morphology characteristics around the tandem piers under the clear-water scour and live-bed scour environments were obtained in the final simulation. By capturing the cross-sectional vortex and bed shear stress during the scouring process, the characteristic pattern of scouring topography around the pier and the relationship between the scour hole structure scale were analyzed, and the relationship equation between the development of scour depth and time scale was established. The study shows that: under the clear-water scouring environment, the sediment transport rate lags behind, but the contribution time is superior; under the live-bed scouring environment, by the shading and reinforcement influence of the upstream piers, the extent and development of the downstream pier surrounding the scour hole is small; the development trend of the maximum sediment transport rate of the scour hole and the great value of the shear stress is more synergistic, and the peri-pier eddy is positively correlated with the bed shear stress; through the regression equation to compare the relevant test and simulation results, the two are in good agreement, indicating that the simulated local scour evolution law is consistent with the actual law.
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Shirazi, Malihe, Maryam Zarnaghash i Alireza Dashti. "The Effect of Social Skills through Role-play on the Self-concept of Students with and without ADHD". New Trends and Issues Proceedings on Humanities and Social Sciences 4, nr 7 (3.11.2017): 01–07. http://dx.doi.org/10.18844/prosoc.v4i3.2617.
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The aim of the present research is to find out the effect of role-playing on total self-concept score of students suffering from ADHD (attention-deficit hyperactivity disorder). Participants of this study were 120 children divided into two groups of 60. The first group included ADHD children, and the second group were normal children. The participants in the second group were randomly selected among the students of a primary school. The research instruments were ADHD Questionnaire (Tavakoli, 1380), Piers-Harris Children's Self-Concept, and Scale Role-playing scenarios & Clinical interview. The data gathered through the questionnaires were analyzed by the t-test. This is the indicator of a positive effect of role-playing on selfconcept of the students with or without ADHD.
Keywords: role-playing; self-concept; ADHD;
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Shirazi, Malihe, Maryam Zarnaghash i Alireza Dashti. "The Effect of Social Skills through Role-play on the Self-concept of Students with and without ADHD". New Trends and Issues Proceedings on Humanities and Social Sciences 4, nr 7 (5.08.2017): 01–07. http://dx.doi.org/10.18844/prosoc.v4i7.2617.
Pełny tekst źródłaStreszczenie:
The aim of the present research is to find out the effect of role-playing on total self-concept score of students suffering from ADHD (attention-deficit hyperactivity disorder). Participants of this study were 120 children divided into two groups of 60. The first group included ADHD children, and the second group were normal children. The participants in the second group were randomly selected among the students of a primary school. The research instruments were ADHD Questionnaire (Tavakoli, 1380), Piers-Harris Children's Self-Concept, and Scale Role-playing scenarios & Clinical interview. The data gathered through the questionnaires were analyzed by the t-test. This is the indicator of a positive effect of role-playing on selfconcept of the students with or without ADHD.
Keywords: role-playing; self-concept; ADHD;
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NOMURA, Toshio, Yozo FUJINO i Toshiaki KATO. "Aerodynamic Characteristics of Circular Cylinders in a Group for Constructing Composite Steel Tube Reinforced Concrete Bridge Piers." Doboku Gakkai Ronbunshu, nr 724 (2003): 103–14. http://dx.doi.org/10.2208/jscej.2003.724_103.
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Malik, Rahul, i Baldev Setia. "Prediction of Scour Depth in a Group of Piers in Staggered Arrangement Using Experimental and Regression Models". Journal of The Institution of Engineers (India): Series A 101, nr 1 (12.12.2019): 141–52. http://dx.doi.org/10.1007/s40030-019-00420-9.
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Sreedhara, B. M., Amit Prakash Patil, Jagalingam Pushparaj, Geetha Kuntoji i Sujay Raghavendra Naganna. "Application of gradient tree boosting regressor for the prediction of scour depth around bridge piers". Journal of Hydroinformatics 23, nr 4 (3.06.2021): 849–63. http://dx.doi.org/10.2166/hydro.2021.011.
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Abstract Scour around bridge piers is a complex phenomenon and it is essential to assess or predict the scour hazard around bridge piers in tandem with completely understanding its mechanism. To date, there is no exact method for the estimation of scour depth. Nowadays, machine learning techniques are being recognized as effective tools for the prediction of scour depth using experimental data. In the present study, gradient tree boosting (GTB) technique was used for the prediction of scour depth around various pier shapes under different streambed conditions. Sediment size, sediment quantity, velocity, and flow time were used as input parameters to predict the scour depth under clear-water and live-bed scour conditions. The scour depth was predicted for different pier shapes such as, circular, rectangular, round-nosed and sharp-nosed shaped. The GTB model predicted scour depth values were compared with that of the group method of data handling (GMDH) technique. The performance of GTB and GMDH models were then evaluated based on statistical indices such as RRMSE, NNSE, WI, MNE, SI, and KGE. The study concludes that the GTB model performance was relatively superior to that of GMDH in the prediction of scour depth around different pier shapes.
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Rechtik, Zdenek. "Motor skills in context of popularity in a group of school classes in children". New Trends and Issues Proceedings on Humanities and Social Sciences 4, nr 6 (30.12.2017): 122–29. http://dx.doi.org/10.18844/prosoc.v4i6.2921.
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Self-concepts of very young children are consistently high but that with increasing life experience, and children learn their relative strengths and weaknesses, so that mean levels of self-concept decline, multiple dimensions of self-concept become more differentiated. Self-concepts become more highly correlated with external indicators of competence (skills and accomplishments). Well-developed motor abilities lead to positive feedback from significant others (teachers, parents, peers) which are related to positive emotions and motivation for physical activity. The data were measured by Piers–Harris questionnaire, and the level of motor skills was monitored by TGMD – two tests within the project IGA_PdF_2017_002. The research group consisted of 300 pupils (149 boys and 151 girls) in the middle school age (9–11 years). Based on the research results, we can say that the level of gross motor skills contributes on child’s adaptation in the group of school classes. It is necessary to examine this area further, support physical activity of children in young school age and intentionally develop children’s motor skills. Keywords: Primary school, children, school class, gross motor skills.
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Hruštinec, Luboš. "ANALYSIS OF THE TIME COURSE OF A BRIDGE ABUTMENTS SETTLEMENT". Acta Polytechnica CTU Proceedings 16 (19.06.2018): 11. http://dx.doi.org/10.14311/app.2018.16.0011.
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The paper deals with the time course of the bridge abutments settlement (consolidation of the subsoil) on the motorway D4 in Stupava, Slovakia. The bridge abutments are founded on an earth embankment 5.5 meters in height and a group of piles. Over 6 years of geotechnical monitoring after the construction of bridge abutments, there were measured settlements from 102 to 106 mm. The measured settlement of intermediate bridge piers was only up to 16 mm. Geotechnical calculations and analysis are focused on the comparison of the final settlements prognosis and its time course with the real measured values.
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Miklankova, Ludmila. "Motor skills as a predictor of adaptive behaviour of pupils – pilot study". New Trends and Issues Proceedings on Humanities and Social Sciences 4, nr 6 (30.12.2017): 202–9. http://dx.doi.org/10.18844/prosoc.v4i6.2931.
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The level of motor skills is an important indicator of a child’s optimal growth and development. Shortcomings in this area can cause a gradual decrease in the child’s activity in the school group, which negatively effects the child’s adaptive behaviour. The aim of this pilot study was to analyse the relationship between the level of motor skills and the ability to adapt in a given social group – school class. The research group obtained 110 pupils of primary school aged 9–11. The data about adaptive behaviour skills were collected by Piers-Harris Children’s Self-Concept Scale 2. The level of motor skills was monitored by TGMD-2 test. The research was authorised by the ethical committee of the pedagogical faculty at Olomouc. The aimed development of motor skills could lead to adaptation of pro-social behaviour also in older age categories. The data were collected within the Project IGA_PdF_2017_002. Keywords: Motorics, primary school, readjustment, children
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Dr. Pham Thi Le Hang. "THE EFFECT OF THE EXERCISE PROGRAMS ON THE BOY’S SELF-CONCEPT". Innovative Journal of Medical and Health Science 9, nr 5 (31.05.2019): 435–39. http://dx.doi.org/10.15520/ijmhs.v9i5.2585.
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This study is to investigate the effectiveness of an exercise program for children from10 to 11 years old. In this study, 30 subjects were divided into two groups of equalcontrol and training. After completing the procedure, the participants in the traininggroup performed the gymnastics training program for 12 weeks and the controlgroup did nothing. Data collection tool is a demographic questionnaire and a scale ofself-concept Piers-Harris. Kolmogorov-Smirnov test is used to test the normal distributionof samples. The research results show that in the training group, the size ofthe concept of self and the general self concept of children before and after exerciseinstrument increased significantly. The results also show that the size of happinessand satisfaction of children, both in the control group and in the training group, issignificantly different. The study, concluded that a training program in the field ofgymnastics training has significantly increased the level of self-concept of children.
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Andersson, G. B., C. Gillberg, E. Fernell, M. Johansson i A. Nachemson. "Children with surgically corrected hand deformities and upper limb deficiencies: self-concept and psychological well-being". Journal of Hand Surgery (European Volume) 36, nr 9 (28.06.2011): 795–801. http://dx.doi.org/10.1177/1753193411412869.
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We studied self-concept and psychological well-being in children with hand deformities and upper limb deficiencies. Ninety-two children, 53 boys, 39 girls, aged 9–11 years were included. The children were divided into two subgroups – one with milder (less visible) deformities and one with severe (more complex and visible) finger–hand–arm deformities. Of the 92 children, 79 had received reconstructive surgery, and 13 had been treated with prostheses. The Piers–Harris Children’s Self-Concept Scale (PHCSCS) was used to measure self-esteem and well-being. Overall PHCSCS scores showed that the whole hand deformity group had ‘good’ self-concept with mean scores in excess of 60 points, equal to a comparison group of healthy children. Within the hand deformity group, those with mild deformities had lower scores than those with severe deformities. This result was also found in the group of boys but not in the girls. The children with severe deformities had even higher scores than the comparison group regarding the subscale ‘Intellectual and School Status’. The children with milder deformities had lower scores than the comparison group regarding the subscale ‘Popularity’.
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Xie, Wen, i Limin Sun. "Experimental and computational assessment of shear beams as earthquake resilient measure for double-column piers supported by pile-group". Engineering Structures 242 (wrzesień 2021): 112509. http://dx.doi.org/10.1016/j.engstruct.2021.112509.
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Saghravani, S. F., i A. Azhari. "Simulation of clear water local scour around a group of bridge piers using an Eulerian 3D, two-phase model". Progress in Computational Fluid Dynamics, An International Journal 12, nr 5 (2012): 333. http://dx.doi.org/10.1504/pcfd.2012.049097.
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Wright, Jennifer, i Jo E. Cowden. "Changes in Self-Concept and Cardiovascular Endurance of Mentally Retarded Youths in a Special Olympics Swim Training Program". Adapted Physical Activity Quarterly 3, nr 2 (kwiecień 1986): 177–83. http://dx.doi.org/10.1123/apaq.3.2.177.
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Although It has been said that Special Olympics competition contributes significantly to the physical fitness and self-concept of mentally retarded participants, no experimental research has been reported on the Special Olympics program. The purpose of this study was to investigate changes in self-concept and cardiovascular endurance of mentally retarded youths after participating in a Special Olympics swim training program. One group (N = 25) participated in a 10-week Special Olympics swim training program, while the control group (N = 25) adhered to their normal daily living activities. The 9-Minute Run/Walk test yielded the data for measuring cardiovascular endurance, and the Piers and Harris Children’s Self-Concept Scale was selected to measure self-concept. Results of the analysis of variance for each test were significant. It was concluded from the findings of this study that participation of mentally retarded youth in a Special Olympics swim training program contributed to a significant increase in self-concept and cardiovascular endurance.
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Sun, Guangjun, Zhijie Yuan, Bingyan Wu i Fu Zhao. "Methodology and Application of Safety Evaluation of Reinforced Concrete Girder Bridges during Earthquakes". Shock and Vibration 2022 (6.01.2022): 1–12. http://dx.doi.org/10.1155/2022/5591334.
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The actual earthquake resistance performance and the seismic damage state of bridges during future earthquakes are important issues that need to be resolved. Using an expressway reinforced concrete (RC) girder bridge in a high seismic intensity area of China as the research object, the damage correlation between different structural components of the bridge is analyzed, and the key components that determine the structural safety state of the bridge are determined. Then, the safety evaluation indexes of the bridge pier and bearing are researched, and a two-stage seismic safety evaluation methodology for RC girder bridges is proposed. The first stage is a rapid and general evaluation using empirical statistical methods, and the second stage is a precise evaluation obtained by calculating the damage index of the components. Subsequently, the seismic damage prediction matrix is presented. Considering the modification of the bridge span number, service life, and skew angle, a seismic safety evaluation from a typical single bridge to a group of bridges of the same type is implemented. Finally, an actual expressway bridge in China is presented as a numerical example to illustrate the application of the method. The research results show that damage to the key components, including bearings, piers, and abutments, is the deciding factor of the bridge damage state. The seismic damage states of piers and bearings can be conveniently assessed according to the pier top displacement angle and bearing shear deformation during earthquakes. According to the suggested standard of RC girder bridge seismic damage, the seismic safety evaluation of the whole bridge structure can be obtained using the seismic safety evaluation of individual key components of the bridge structure. According to the evaluation results of individual bridges and considering the modification of influencing factors, an earthquake performance evaluation of a group of bridges of the same type can be obtained. The two-stage seismic safety evaluation methodology proposed in this study is effective and efficient.
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Ma, Rujin, Yi Liu, Haocheng Chang i Zhenkun Hong. "Effect of Square Cap on Pile-Group Wave Force: Parametric Analysis and Case Study". Journal of Marine Science and Engineering 11, nr 9 (25.08.2023): 1677. http://dx.doi.org/10.3390/jmse11091677.
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The square cap is a typical semi-submersible component of sea-crossing bridges, which connects piers and pile-group foundations. As the cap size is large, it usually has a non-negligible influence on the wave motion around the pile-group foundation, so it is not considered in the relevant specification. However, neglecting this influence may have adverse effects on the structure. In this paper, the wave forces on capped pile groups are simulated by a numerical wave flume. Firstly, the numerical flume used in this paper is validated by an experiment in the previous literature. Then, capped pile groups with different arrangements and different water levels are modeled to study the interference effect of the square cap on the wave force, and the variation law of the interference effect coefficient Kcp of the cap is given. Next, we introduce Kcp into the theoretical formula of wave forces on pile groups and obtain a modified formula that considers the cap effect. To verify the feasibility of the modified formula in practical engineering, we use the formula to calculate the wave forces acting on capped pile groups of a sea-crossing bridge. The results of the modified theoretical formula are compared with that of the numerical water flume and recommended values in the specification. It is found that the theoretical values are relatively close to the numerical results, while the specification values tend to be conservative. The modified theoretical formula proposed in this paper and the obtained parameter distribution law can provide a reference for engineering design.
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Boonyarak, Thayanan, Kullapat Phisitkul, Charles W. W. Ng, Wanchai Teparaksa i Zaw Zaw Aye. "Observed ground and pile group responses due to tunneling in Bangkok stiff clay". Canadian Geotechnical Journal 51, nr 5 (maj 2014): 479–95. http://dx.doi.org/10.1139/cgj-2013-0082.
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A 5.15 m diameter water diversion tunnel was driven into Bangkok stiff clay using an earth pressure balance shield. The tunnel was driven within a clear distance of 2 m from the closest pile of a 3 × 4 pile group supporting an expressway. During construction, tunnel driving parameters as well as induced ground and pile group responses were recorded. To avoid cutting the piles supporting the expressway, the alignment of the tunnel was adjusted and curved. As a result of this change in tunnel alignment, the tunnel advancing rate was reduced from an average 17 m/day for a straight drive to an average of only 6 m/day for the curved alignment, and the ratio between the tunnel face pressure and overburden pressure was changed from 0.5 to 0.4, accordingly. Due to the reduction of the tunnel face pressure, up to a 280% larger inward ground movement towards the tunnel was observed. As the shield penetration rate decreased, the torque required for tunnel driving was reduced by 33%, while the ratio between shield penetration rate and soil extraction was almost constant throughout the tunnel route. A transverse influence zone due to tunnel driving was identified to extend up to a distance that was twice the tunnel diameter radially from the longitudinal tunnel axis. The maximum tilting of the expressway pier and deduced differential settlement of the pile located within the influence zone were up to 1:2600 and 2.0 mm, respectively. Tilting of all the piers was mainly caused by long-term subsurface settlement having the tilting direction towards the tunnel. This long-term subsurface settlement was up to about 80% of the total.
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Najafzadeh, M., i Gh A. Barani. "Comparison of group method of data handling based genetic programming and back propagation systems to predict scour depth around bridge piers". Scientia Iranica 18, nr 6 (grudzień 2011): 1207–13. http://dx.doi.org/10.1016/j.scient.2011.11.017.
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Halabian, Amir M., Ibrahim Naeemifar i S. Hamid Hashemolhosseini. "Numerical analysis of vertically loaded rammed aggregate piers and pier groups". Proceedings of the Institution of Civil Engineers - Ground Improvement 165, nr 3 (sierpień 2012): 167–81. http://dx.doi.org/10.1680/grim.10.00041.
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Ivanović, Željko. "DYMEMULP – Dynamic Model of Process Optimisation in Regional Logistics". Promet - Traffic&Transportation 35, nr 3 (28.06.2023): 364–79. http://dx.doi.org/10.7307/ptt.v35i3.203.
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The expansion of logistics requirements, limited space and strict requirements of generators of logistics requests (GLR) in terms of service quality complicate the supply of the region, resulting in the necessity to improve logistics models (MoL). Proximity to water, the presence of ports and piers along the coast, new eco vehicles and the development of cooperation between land and water transport are elements for improving the existing MoLs in an economically and environmentally acceptable way. Research on the development of an improved multi-echelon logistics network with variable terminals including the coordination and cooperation of a heterogeneous group of transport agencies for the realisation of goods flows represents an innovation in regional logistics (RL). This article presents an integrated MoL development process using dynamic optimisation with a focus on spatial, temporal, transport, economic and environmental components.
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Luliquis, Shamir, Samuel Vinces i Rubén Mogrovejo. "Evaluation through 2D Modelling of Scour around Piers with Collars in the CÁCeres Bridge in Piura, Peru". E3S Web of Conferences 422 (2023): 03005. http://dx.doi.org/10.1051/e3sconf/202342203005.
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This paper analyzes the results of the scour calculations around the group of piers of a bridge through two-dimensional modelling using the Iber software. The case under study is that of the Andrés Avelin o Cáceres Bridge, located in the Piura region, Peru, which has an approximate free span of 120 meters and has 10 pillars equally distributed on two decks. Currently, the referred bridge has pillars of rectangular section with narrowing towards the base, this type of geometry was considered as the first scenario for scour calculations; the pillars with the collars installed are part of the second scenario under study. Based on geotechnical, hydrological and hydraulic studies of the area, two-dimensional numerical modeling has been developed for each scenario in order to obtain the depths of scour. The following results were obtained: The installation of collars in the second scenario achieved a reduction of the scour depth by 29.51% on average, the observed reduction range was from 15.73% to 43.77%.
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Huang, Hongyu, Lili Liu, Shaoyu Su i Dandan Xie. "Self-consciousness and depression in precocious pubertal children". Journal of International Medical Research 49, nr 5 (maj 2021): 030006052110202. http://dx.doi.org/10.1177/03000605211020227.
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Objective To explore self-consciousness and depression in children with precocious puberty (PP) and analyse its effect on children of both sexes. Methods Sixty children with PP and 60 non-PP children matched for sex and age participated in the study. Children were assessed using the Birleson Depression Self-Rating Scale for Children and the Piers–Harris Children’s Self-Concept Scale. Results There were significant differences in physical appearance and attributes, anxiety, happiness and satisfaction between PP children and non-PP children. PP children had significantly higher depression than non-PP children. In the PP group, girls were significantly more prone to anxiety and unhappiness than boys. Conclusion: There were sex differences in the effect of PP on children’s self-consciousness, and girls were more prone to anxiety and unhappiness. More attention should be paid to improving the physical and mental health of children with PP.
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Tariq, Moiz, Azam Khan i Mujahid Khan. "Experimental Study of Scour Hole Depth around Bridge Pile Using Efficient Cross-Section". Applied Sciences 12, nr 10 (20.05.2022): 5205. http://dx.doi.org/10.3390/app12105205.
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Extensive numerical and analytical studies exist that focus on the scours around bridge piers with different cross-sections. However, studies addressing the scour around bridge piles are rather limited and not conclusive. Therefore, the most efficient cross-section reducing the local scour around a pile group is experimentally examined herein. Accordingly, comparative scouring of three different shapes, namely, circular, rectangular and lenticular, is investigated by installing a cohesion-less bedding material around scaled bridge piles immersed in clear water. It is also shown that the available pier scour predictive models grossly underestimate the depth of pile scour holes. For example, the pier predictive models underestimate the pile scours hole by more than 50% in the case of square and circular cross-sections. It also transpires from the experimental investigation that the scour hole depth around the square shape pile is significant, around the circular pile is moderate and around the lenticular pile is minimal.
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HARITOS, NICHOLAS. "ASSESSING THE INFLUENCE OF MODIFICATIONS ON IN-SERVICE PERFORMANCE OF STRUCTURAL SYSTEMS USING VIBRATION MEASUREMENTS". International Journal of Structural Stability and Dynamics 09, nr 04 (grudzień 2009): 729–44. http://dx.doi.org/10.1142/s0219455409003260.
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This paper outlines application of dynamic testing to three separate structures where evaluations of their in-service condition and performance were required. In two of these cases, both bridges, model updating procedures enabled identification of key structural properties for performing an integrity assessment. In the case of the first bridge, dynamic testing was able to demonstrate that the first attempt at introducing bandbeams to strengthen the bridge over its piers was virtually ineffective in stiffening the bridge. However, after these bandbeams were replaced, similar dynamic testing verified that the new work was now in fact so effective in stiffening this same bridge. Dynamic testing of the second bridge, a historical wrought iron swing bridge, was able to verify the integrity of the central pile group about which this bridge swings to allow riverboats to pass through. For the third case, involving a specialist laboratory floor system, a variety of excitation options were exercised to establish the acceptability of the floor to stringent criteria on vibration response levels.
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Lupart, Judy L., i Michael C. Pyryt. "“Hidden Gifted” Students: Underachiever Prevalence and Profile". Journal for the Education of the Gifted 20, nr 1 (1.10.1996): 36–53. http://dx.doi.org/10.1177/016235329602000103.
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The purpose of the present study was to provide a reasonably accurate estimate of the prevalence of one type of “hidden gifted” population (gifted underachievers) and to identify some of the key academic and personal characteristics that define this group. Study participants were selected from 19 elementary, junior, and senior high schools in a large Western Canadian urban school district. A formula was used to identify grades 4, 7, and 10 students whose measured intellectual potential was 120 or higher and who demonstrated a significant achievement-potential discrepancy. Out of a total of 80 prospective students, a final sample of 58 students was administered the Woodcock-Johnson Psychoeducational Battery-Revised (WJPB-R), the Piers-Harris Self-Concept Scale (PHSCS), and Thinking About My School (TAMS). Results of a MANOVA and discriminant analysis indicate that there was a significant interaction effect between gender and school level and a significant grade-level effect. Major findings were: (a) achievement scores on the WJPB-R were higher than their course grades; (b) there was a significant decline in attitudes toward school for this group of students at the junior high level, particularly for females; and (c) overall achievement declined as students progress from grade 4 to grades 7 and 10.
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Naz, Shaista, i Nasir Sulman. "A Comparative Study Of The Efficacy Of Intervention Program On Girl Children With Mental Retardation". Pakistan Journal of Gender Studies 6, nr 1 (8.12.2012): 205–17. http://dx.doi.org/10.46568/pjgs.v6i1.410.
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This study was an attempt to compare self-concept and adjustment state of mentally retarded girls who were attending the special school (with intervention program), who are not attending the special school (without intervention program) and normal healthy girls attending regular school. The investigator hypothesized that the mentally retarded girls with an intervention program would differ socially and emotionally from the mentally retarded girls without an intervention program. For the nature of the design of the study, participants for this study were divided into three groups. With the help of purposive sampling (non-probability method), the participant girls were selected in such a manner that ten girls in each group were matched in age and severity with girls in each of the three groups. For the purpose of data collection, Piers Harris Children’s Self Concept Scale and The AML Rating Scale were used by the investigators. The findings of the study thus did confirm on the whole the assumption that mentally retarded girls with an intervention program would differ emotionally and socially from mentally retarded girls without intervention program.
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Wilson, Darrell M., Elizabeth McCauley, David R. Brown i Robert Dudley. "Oxandrolone Therapy in Constitutionally Delayed Growth and Puberty". Pediatrics 96, nr 6 (1.12.1995): 1095–100. http://dx.doi.org/10.1542/peds.96.6.1095.
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Background. Male adolescents with constitutional delay of growth and puberty may have significant psychosocial difficulties related to their sexual immaturity and short stature. The purpose of this study was to test the hypothesis that 1 year of oxandrolone therapy would increase growth velocity and thereby improve psychosocial functioning in boys with constitutional delay of growth and pubertal development. Methods. Forty boys (ages 11 to 14.7 years) with delayed pubertal development and short stature were recruited from the pediatric endocrine clinics of 14 medical centers. The boys were randomized using a block design stratified for age to receive either oxandrolone (0.1 mg/kg daily for 1 year) or an identical-appearing placebo tablet, using a double-masked design. Results. Growth velocity in the oxandrolone-treated boys was significantly greater than in the control boys (9.5 vs 6.8 cm/y). Likewise, the mean height SD score increased 0.41 in the oxandrolone group, whereas it decreased 0.03 in the control group. Those in the oxandrolone group gained 2.4 kg more than those in the placebo group. Mean predicted adult heights did not change in either group. The mean rates of pubertal progression were equivalent in both groups. Self-image (Piers-Harris Self Concept Scale) and social competence (Child Behavior Profile) were normal at baseline in both groups and did not change significantly over the course of the study in either group. No complications of oxandrolone therapy were identified. Conclusions. This randomized, placebo-controlled trial demonstrates that low-dose oxandrolone can increase both height and weight velocity in boys with delayed puberty safely. Under the conditions of this study, however, the increased growth velocity in the oxandrolone-treated boys was not associated with a greater improvement in psychosocial status compared with the control boys.