577 resultados para Gyro compass


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A tethered remote instrument package (TRIP) has been developed for biological surveys over Queensland's continental shelf and slope. The present system, evolved from an earlier sled configuration, is suspended above the sea bed and towed at low speeds. Survey information is collected through video and film cameras while instrument and environmental variables are handled by a minicomputer. The operator was able to "fly" the instrument package above the substrate by using an altitude echosounder, forward-looking sonar and real-time television viewing. Unwanted movements of the viewing system were stabilized through a gyro-controlled camera-head panning system. the hydrodynamic drag of the umbilical presented a major control problem which could be overcome only by a reduction in towing speed. Despite the constraints of towing a device such as this through the coral reef environment, the package performed well during a recent biological survey where it was worked at 50% of its 350 m design depth.

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Balance and stability are very important for everybody and especially for sports-person who undergo extreme physical activities. Balance and stability exercises not only have a great impact on the performance of the sportsperson but also play a pivotal role in their rehabilitation. Therefore, it is very essential to have knowledge about a sportsperson’s balance and also to quantify the same. In this work, we propose a system consisting of a wobble board, with a gyro enhanced orientation sensor and a motion display for visual feedback to help the sportsperson improve their stability. The display unit gives in real time the orientation of the wobble board, which can help the sportsperson to apply necessary corrective forces to maintain neutral position. The system is compact and portable. We also quantify balance and stability using power spectral density. The sportsperson is made stand on the wobble board and the angular orientation of the wobble board is recorded for each 0.1 second interval. The signal is analized using discrete Fourier transforms. The power of this signal is related to the stability of the subject. This procedure is used to measure the balance and stability of an elite cricket team. Representative results are shown below: Table 1 represents power comparison of two subjects and Table 2 represents power comparison of left leg and right leg of one subject. This procedure can also be used in clinical practice to monitor improvement in stability dysfunction of sportsperson with injuries or other related problems undergoing rehabilitation.

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Among various MEMS sensors, a rate gyroscope is one of the most complex sensors from the design point of view. The gyro normally consists of a proof mass suspended by an elaborate assembly of beams that allow the system to vibrate in two transverse modes. The structure is normally analysed and designed using commercial FEM packages such as ANSYS or MEMS specific commercial tools such as Coventor or Intellisuite. In either case, the complexity in analysis rises manyfolds when one considers the etch hole topography and the associated fluid flow calculation for damping. In most cases, the FEM analysis becomes prohibitive and one resorts to equivalent electrical circuit simulations using tools like SABER in Coventor. Here, we present a simplified lumped parameter model of the tuning fork gyro and show how easily it can be implemented using a generic tool like SIMULINK. The results obtained are compared with those obtained from more elaborate and intense simulations in Coventor. The comparison shows that lumped parameter SIMULINK model gives equally good results with fractional effort in modelling and computation. Next, the performance of a symmetric and decoupled vibratory gyroscope structure is also evaluated using this approach and a few modifications are made in this design to enhance the sensitivity of the device.

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We discuss the possibility of using electroproduction of J/psi as a probe of gluon Sivers function by measuring single spin asymmetry (SSA) in experiments with transversely polarized protons and electron beams. We estimate SSA for JLab, HERMES, COMPASS, and eRHIC energies using the color evaporation model of charmonium production and find asymmetry up to 25% for certain choices of model parameters which have been used earlier for estimating SSA in the SIDIS and Drell-Yan processes.

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We extend our analysis of transverse single spin asymmetry in electroproduction of J/psi to include the effect of the scale evolution of the transverse momentum dependent (TMD) parton distribution functions and gluon Sivers function. We estimate single spin asymmetry for JLab, HERMES, COMPASS, and eRHIC energies using the color evaporation model of charmonium production, using an analytically obtained approximate solution of TMD evolution equations discussed in the literature. We find that there is a reduction in the asymmetry compared with our predictions for the earlier case considered by us, wherein the Q(2) dependence came only from DGLAP evolution of the unpolarized gluon densities and a different parametrization of the TMD Sivers function was used.

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We extend our analysis of transverse single spin asymmetry in electroproduction of J/ψ to include the effect of the scale evolution of the transverse momentum dependent (TMD) parton distribution functions and gluon Sivers function. We estimate single spin asymmetry for JLab, HERMES, COMPASS, and eRHIC energies using the color evaporation model of charmonium production, using an analytically obtained approximate solution of TMD evolution equations discussed in the literature. We find that there is a reduction in the asymmetry compared with our predictions for the earlier case considered by us, wherein the Q2 dependence came only from DGLAP evolution of the unpolarized gluon densities and a different parametrization of the TMD Sivers function was used.

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We present estimates of single spin asymmetry in the electroproduction of J/psi taking into account the transverse momentum-dependent (TMD) evolution of the gluon Sivers function. We estimate single spin asymmetry for JLab, HERMES, COMPASS and eRHIC energies using the color evaporation model of J/psi. We have calculated the asymmetry using recent parameters extracted by Echevarria et al. using the Collins-Soper-Sterman approach to TMD evolution. These recent TMD evolution fits are based on the evolution kernel in which the perturbative part is resummed up to next-to-leading logarithmic accuracy. We have also estimated the asymmetry by using parameters which had been obtained by a fit by Anselmino et al., using both an exact numerical and an approximate analytical solution of the TMD evolution equations. We find that the variation among the different estimates obtained using TMD evolution is much smaller than between these on one hand and the estimates obtained using DGLAP evolution on the other. Even though the use of TMD evolution causes an overall reduction in asymmetries compared to the ones obtained without it, they remain sizable. Overall, upon use of TMD evolution, predictions for asymmetries stabilize.

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We present estimates of single spin asymmetry (SSA) in the electroproduction of taking into account the transverse momentum dependent (TMD) evolution of the gluon Sivers function and using Color Evaporation Model of charmonium production. We estimate SSA for JLab, HERMES, COMPASS and eRHIC energies using recent parameters for the quark Sivers functions which are fitted using an evolution kernel in which the perturbative part is resummed up to next-to-leading logarithms accuracy. We find that these SSAs are much smaller as compared to our first estimates obtained using DGLAP evolution but are comparable to our estimates obtained using TMD evolution where we had used approximate analytical solution of the TMD evolution equation for the purpose.

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The present study deals with the diffusion and phase transition behaviour of paraffin reinforced with carbon nano-additives namely graphene oxide (GO) and surface functionalized single walled carbon nanotubes (SWCNT). Bulk disordered systems of paraffin hydrocarbons impregnated with carbon nano-additives have been generated in realistic equilibrium conformations for potential application as latent heat storage systems. Ab initio molecular dynamics(MD) in conjugation with COMPASS forcefield has been implemented using periodic boundary conditions. The proposed scheme allows determination of optimum nano-additive loading for improving thermo-physical properties through analysis of mass, thermal and transport properties; and assists in determination of composite behaviour and related performance from microscopic point of view. It was observed that nanocomposites containing 7.8% surface functionalised SWCNT and 55% GO loading corresponds to best latent heat storage system. The propounded methodology could serve as a by-pass route for economically taxing and iterative experimental procedures required to attain the optimum composition for best performance. The results also hint at the large unexplored potential of ab-initio classical MD techniques for predicting performance of new nanocomposites for potential phase change material applications. (C) 2015 Author(s).

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采用COMPASS力场,通过分子动力学模拟,研究了Ni纳米薄膜的弹性模量的尺寸效应,以及生物分子吸附在Ni表面对其力学性能的影响.计算结果表明,随着厚度的增大,吸附强度也在增强;Ni纳米薄膜的弹性模量随着膜厚的减小而减小.氨基酸在Ni表面的吸附能够提高其弹性模量1~2 GPa,并且表明分子的取向是重要的影响因素.

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Relato a respeito do encontro com representantes dos Escritórios Setoriais de Gestão, cujo objetivo foi apresentar os conceitos de governança de processos e sua consequente implementação na ferramenta IBM Compass.

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内容包括:复合材料及其结构的强度、振动、冲击、疲劳、损伤、粘弹性等力学问题及机敏材料等的力学分析与设计。
目录

第一章 复合材料齿轮粘弹性力学问题的研究&张恒 王震鸣

第一节 引言

第二节 齿轮复合材料的粘弹性

第三节 复合材料齿轮的温度场分析

第四节 复合材料齿轮的粘弹性应力分析

参考文献

第二章 陶瓷基复合材料性能的细观力学研究&杜善义 李文芳

第一节 引言

第二节 陶瓷基复合材料增韧的研究进展

第三节 研究含随机分布微裂纹非均匀体有效性能的一个新模型

第四节 随机分布微裂纹对相变陶瓷力学性能的影响

第五节 随机分布微裂纹对晶须增韧CMC材料性能的影响

第六节 随机分布微裂纹对延性相增韧CMC材料力学性能的影响

参考文献

第三章 动态松弛法及其在复合材料叠层板壳非线性分析中的应用&黄小清 范赋群

第一节 引言

第二节 动态松弛法的基本原理

第三节 求解叠层板及叠层扁壳的经典非线性弯曲问题

第四节 求解双模量复合材料叠层板的非线性弯曲问题

第五节 求解复合材料叠层平板与圆柱微曲板的非线性稳定问题

第六节 对叠层板的线性和非线性初始破坏分析

第七节 结束语

参考文献

第四章 单向复合材料损伤本构模型的细观分析&夏源明 袁建明 杨报昌

第一节 引言

第二节 单向复合材料的一维损伤本构模型

第三节 单向复合材料的Monte Carlo数值模拟

第四节 单向复合材料冲击拉伸过程的Monte Carlo数值模拟

第五节 结束语

参考文献

第五章 短纤维复合材料的弹性与弹塑性行为的理论研究&陈浩然 杨庆生

第一节 引言

第二节 短纤维复合材料的特点

第三节 短纤维复合材料的弹性性能

第四节 短纤维复合材料的弹塑性性能

第五节 结束语

参考文献

第六章 复合材料中的应力波&张继栋

第一节 引言

第二节 层状无限介质中的波

第三节 均匀各向异性板中的波

第四节 各向异性层合板中的波与弹性力学方法

第五节 各向异性层板中的波与近似方法

第六节 复合材料中应力波的细观力学分析

第七节 应力波的实验研究

参考文献

第七章 半解析数值法在复合材料及其结构力学问题中的应用&洪志泉 方赤峰

第一节 引言

第二节 半解析数值法的概述

第三节 半解析数值法的应用

第四节 结束语

参考文献

第八章 复合材料界面和界面力学的几个问题&伍章健 余寿文

第一节 引言

第二节 界面研究的几个基本问题

第三节 复合材料界面的细观力学研究方法

第四节 界面相与复合材料桥联协同作用的机理

第五节 界面断裂力学

第六节 复合材料界面力学的实验

第七节 结论和展望

参考文献

第九章 超高模聚乙烯纤维增强复合材料的力学性能和微观结构&冼杏娟

第一节 引言

第二节 纵向的比拉伸强度和比刚度高

第三节 优越的能量吸收性能

第四节 界面粘结对UHMPE纤维复合材料力学性能的影响

第五节 UHMPE纤维与其他高性能纤维混杂时的混杂效应

第六节 UHMPE纤维编织复合材料的力学性能

第七节 UHMPE纤维增强复合材料的动态力学性能

第八节 加工方法对UHMPE纤维复合材料试件力学性能的影响

第九节 UHMPE纤维及其复合材料的其他性能

第十节 结束语

参考文献

第十章 机敏材料和机敏结构的研究进展&孙国钧 茅人杰

第一节 引言

第二节 机敏材料在主动振动控制技术中的应用前景

第三节 光纤在机敏结构中的应用

第四节 电流变体在机敏结构中的应用

第五节 形状记忆合金增强复合材料

第六节 压电材料在机敏结构中的应用

第七节 结束语

参考文献

第十一章 复合材料离散加筋曲板在面内载荷作用下用于屈曲分析的有限条法&童贤鑫 B・盖尔

第一节 引言

第二节 典型的复合材料曲板条元素的分析

第三节 结构屈曲判别式的建立

第四节 解法,算例和计算结果

第五节 小结

参考文献

附录

第十二章 在湿热环境下碳纤维/树脂复合材料结构强度的研究…………

俞树奎 和润忠 郑锡涛

第一节 引言

第二节 飞机复合材料结构的湿热环境设计准则

第三节 复合材料的吸湿规律和预浸润技术

第四节 湿热环境对复合材料力学性能的影响

第五节 在湿热环境下复合材料机械连接件的强度与寿命

第六节 复合材料结构的湿热环境试验系统

第七节 在湿热/温载谱作用下结构强度和耐久性的试验验证

第八节 结束语

参考文献

第十三章 纤维增强复合材料中的桥连裂纹&罗海安

第一节 引言

第二节 桥连裂纹的理论模型

第三节 桥连裂纹的稳定性

第四节 桥连裂纹的临界载荷

参考文献

第十四章 复合材料层板的强迫振动问题&沈大荣 李华

第一节 引言

第二节 几类典型铺设层板线性强迫振动方程的推导

第三节 几类典型铺设层板线性强迫振动问题的数值计算

第四节 几类典型铺设层板的非线性强迫振动分析

第五节 几类典型铺设层板非线性强迫振动问题的数值计算

第六节 讨论和结论

参考文献

第十五章 复合材料机翼在气动弹性和强度约束下的设计剪裁研究&丁惠梁

第一节 引言

第二节 COMPASS系统的结构配置

第三节 结构分析与灵敏度分析

第四节 优化剪裁技术

第五节 实例应用

第六节 结束语

参考文献

第十六章 复合材料梁的强度、冲击和疲劳性能的研究&薛元德 陈心爽 刘壮健

第一节 引言

第二节 损伤和破坏机制

第三节 复合材料梁的强度

第四节 冲击性能

第五节 疲劳

参考文献

第十七章 金属-陶瓷梯度材料的优化设计&王继辉 张清杰 吴代华

第一节 引言

第二节 梯度材料的微观结构特征

第三节 梯度材料的微观力学和性能预测

第四节 热应力分析和设计模型

第五节 热应力分析结果与讨论

第六节 结论

参考文献

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Management of coastal development in Hawaii is based on the location of the certified shoreline, which is representative of the upper limit of marine inundation within the last several years. Though the certified shoreline location is significantly more variable than long-term erosion indicators, its migration will still follow the coastline's general trend. The long-term migration of Hawaii’s coasts will be significantly controlled by rising sea level. However, land use decisions adjacent to the shoreline and the shape and nature of the nearshore environment are also important controls to coastal migration. Though each of the islands has experienced local sea-level rise over the course of the last century, there are still locations across the islands of Kauai, Oahu, and Maui, which show long- term accretion or anomalously high erosion rates relative to their regions. As a result, engineering rules of thumb such as the Brunn rule do not always predict coastal migration and beach profile equilibrium in Hawaii. With coastlines facing all points of the compass rose, anthropogenic alteration of the coasts, complex coastal environments such as coral reefs, and the limited capacity to predict coastal change, Hawaii will require a more robust suite of proactive coastal management policies to weather future changes to its coastline. Continuing to use the current certified shoreline, adopting more stringent coastal setback rules similar to Kauai County, adding realistic sea-level rise components for all types of coastal planning, and developing regional beach management plans are some of the recommended adaptation strategies for Hawaii. (PDF contains 4 pages)

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With the aid of the German Research Association in the central programme 'Sand movements in the German coastal region', an investigation into the current conditions in the shallow water areas of the coasts of the south-eastern North Sea between Sylt and the Weser estuary was carried out by the author. Foundations of the work are 19 continuous current recordings in five profiles normal to the coast from years 1971 to 1973. Off the coasts of the south-eastern North Sea varying tidal currents impinge; they are currents whose directions may vary periodically through all points of the compass. They are caused by the circulating tides in the North Sea (Amphidromien). The turning flow movement experiences a deformation in the very shallow coastal waters, and as it happens the flow turning movement in the case of high tide continues right up onto the outer flats, while here and in the fore-lying shallow water areas around the time of low water (on account of the small depths of waters), there prevails a more variable current. A result of this hydrodynamical procedure is the development of counter currents. This partial translation of the original paper provides the summary of this study of of the mudflat areas between the Elbe and Weser.

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O litoral centro-sul do estado de Santa Catarina representa a mais importante área de concentração reprodutiva das baleias-franca-austral, Eubalaena australis, no Brasil. O objetivo deste estudo é caracterizar o padrão comportamental dos pares fêmea-filhote que migram para essas áreas ao longo de 10 temporadas reprodutivas (2003 a 2012). Observações realizadas em pontos fixos foram conduzidas de Julho a Novembro, entre 2003 e 2012, de seis a sete vezes por semana, entre as 6:00h e 17:00h. Os dados foram coletados com auxilio de binóculos Pentax 12x55 mm, bússola, relógio digital, e registrados em fichas de campo padronizadas. Os estados comportamentais (natação, descanso e ativo) foram registrados em intervalos de cinco minutos e a frequência de eventos registrada em cada intervalo de cinco minutos. Natação foi o estado comportamental que prevaleceu tanto para fêmeas e filhotes, seguido de descanso e ativo para as fêmeas e seguido de ativo e descanso para os filhotes. A natação e o descanso são importantes para as fêmeas pois exigem menos energia, já que precisam usá-la para atividades das quais a sobrevivência da espécie depende, como parir, amamentar e cuidar dos filhotes. Para os filhotes, o comportamento ativo é mais importante para o seu desenvolvimento motor e preparação para o processo migratório. Os eventos mais expressados por ambos fêmea e filhote foram exposições indefinidas, estas sendo duas vezes maior para os filhotes. Os filhotes apresentaram comportamentos aéreos em taxas maiores do que as fêmeas, o que denota a importância de tais comportamentos no auxílio ao desenvolvimento da coordenação e na aptidão motora e no fortalecimento da musculatura, melhorando a resistência para a migração. A taxa de ocorrência de eventos aéreos para as fêmeas foi geralmente mais baixa, provavelmente na tentativa de desencorajar os comportamentos ativos realizados pelos filhotes. Esses resultados reforçam a importância da área de estudo como área reprodutiva para a espécie. O número de baleias-franca está crescendo na área, bem como o potencial conflito com atividades humanas. Entender os padrões comportamentais dos pares fêmea-filhote de baleias-franca-austral no litoral de Santa Catarina podem servir como valiosas ferramentas para a elaboração de planos de manejo, contribuindo para a conservação da espécie no litoral brasileiro