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Sample records for high-capacity inertia welding

  1. Inertia Friction Welding Dissimilar Nickel-Based Superalloys Alloy 720Li to IN718

    Science.gov (United States)

    Huang, Z. W.; Li, H. Y.; Preuss, M.; Karadge, M.; Bowen, P.; Bray, S.; Baxter, G.

    2007-07-01

    This article describes a comprehensive microstructural characterization of an inertia friction welded joint between nickel-based superalloys 720Li and IN718. The investigation has been carried out on both as-welded and postweld heat-treated conditions. The detailed metallographic analysis has enabled the relation of hardness profiles across inertia-welded alloy 720Li to IN718 and morphological changes of the precipitates present. The work demonstrates that inertia friction welding (IFW) 720Li to IN718 results in a weld free of micropores and microcracks and no significant chemical migration across the weld line. However, substantial differences in terms of grain structure and precipitation phase distribution variations are observed on each side of the dissimilar weld. The high γ‧ volume fraction alloy 720Li exhibits a wider heat-affected zone than the mainly γ‧‧ strengthened IN718. Alloy 720Li displays only a small hardness trough near the weld line in the as-welded condition due to the depletion of γ‧, while γ″-strengthened IN718 shows a soft precipitation-free weld region. Postweld heat treatment (PWHT) of the dissimilar weld at 760 °C, a typical annealing temperature for alloy 720Li, results in an overmatch of the heat-affected zone in both sides of the weld. The comparison of the as-welded and postweld heat-treated condition also reveals that IN718 is in an overaged condition after the stress relief treatment.

  2. A Review on Inertia and Linear Friction Welding of Ni-Based Superalloys

    Science.gov (United States)

    Chamanfar, Ahmad; Jahazi, Mohammad; Cormier, Jonathan

    2015-04-01

    Inertia and linear friction welding are being increasingly used for near-net-shape manufacturing of high-value materials in aerospace and power generation gas turbines because of providing a better quality joint and offering many advantages over conventional fusion welding and mechanical joining techniques. In this paper, the published works up-to-date on inertia and linear friction welding of Ni-based superalloys are reviewed with the objective to make clarifications on discrepancies and uncertainties reported in literature regarding issues related to these two friction welding processes as well as microstructure, texture, and mechanical properties of the Ni-based superalloy weldments. Initially, the chemical composition and microstructure of Ni-based superalloys that contribute to the quality of the joint are reviewed briefly. Then, problems related to fusion welding of these alloys are addressed with due consideration of inertia and linear friction welding as alternative techniques. The fundamentals of inertia and linear friction welding processes are analyzed next with emphasis on the bonding mechanisms and evolution of temperature and strain rate across the weld interface. Microstructural features, texture development, residual stresses, and mechanical properties of similar and dissimilar polycrystalline and single crystal Ni-based superalloy weldments are discussed next. Then, application of inertia and linear friction welding for joining Ni-based superalloys and related advantages over fusion welding, mechanical joining, and machining are explained briefly. Finally, present scientific and technological challenges facing inertia and linear friction welding of Ni-based superalloys including those related to modeling of these processes are addressed.

  3. Inertia Friction Welding of Dissimilar Superalloys Mar-M247 and LSHR

    Science.gov (United States)

    Senkov, Oleg N.; Mahaffey, David W.; Semiatin, S. Lee; Woodward, Christopher

    2014-11-01

    The solid state inertia friction welding (IFW) process was used for the first time to join two dissimilar Ni-based superalloys, LSHR, a powder metallurgy alloy, and Mar-M247, a directionally solidified alloy. Extensive studies of the microstructure, phase composition, re-distribution of the alloying elements between the welded alloys, microhardness, and welding defects were conducted at different distances from the weld interface, and the results were correlated with the loading and friction conditions during IFW. Possible reasons leading to the formation of the welding defects were discussed and directions for the further improvement of the quality of the IFW of these two dissimilar alloys were outlined.

  4. Effect of Process Variables on the Inertia Friction Welding of Superalloys LSHR and Mar-M247

    Science.gov (United States)

    Mahaffey, D. W.; Senkov, O. N.; Shivpuri, R.; Semiatin, S. L.

    2016-08-01

    The effect of inertia friction welding process parameters on microstructure evolution, weld plane quality, and the tensile behavior of welds between dissimilar nickel-base superalloys was established. For this purpose, the fine-grain, powder metallurgy alloy LSHR was joined to coarse-grain cast Mar-M247 using a fixed level of initial kinetic energy, but different combinations of the flywheel moment of inertia and initial rotation speed. It was found that welds made with the largest moment of inertia resulted in a sound bond with the best microstructure and room-temperature tensile strength equal to or greater than that of the parent materials. A relationship between the moment of inertia and weld process efficiency was established. The post-weld tensile behavior was interpreted in the context of observed microstructure gradients and weld-line defects.

  5. Efficiency of the Inertia Friction Welding Process and Its Dependence on Process Parameters

    Science.gov (United States)

    Senkov, O. N.; Mahaffey, D. W.; Tung, D. J.; Zhang, W.; Semiatin, S. L.

    2017-07-01

    It has been widely assumed, but never proven, that the efficiency of the inertia friction welding (IFW) process is independent of process parameters and is relatively high, i.e., 70 to 95 pct. In the present work, the effect of IFW parameters on process efficiency was established. For this purpose, a series of IFW trials was conducted for the solid-state joining of two dissimilar nickel-base superalloys (LSHR and Mar-M247) using various combinations of initial kinetic energy ( i.e., the total weld energy, E o), initial flywheel angular velocity ( ω o), flywheel moment of inertia ( I), and axial compression force ( P). The kinetics of the conversion of the welding energy to heating of the faying sample surfaces ( i.e., the sample energy) vs parasitic losses to the welding machine itself were determined by measuring the friction torque on the sample surfaces ( M S) and in the machine bearings ( M M). It was found that the rotating parts of the welding machine can consume a significant fraction of the total energy. Specifically, the parasitic losses ranged from 28 to 80 pct of the total weld energy. The losses increased (and the corresponding IFW process efficiency decreased) as P increased (at constant I and E o), I decreased (at constant P and E o), and E o (or ω o) increased (at constant P and I). The results of this work thus provide guidelines for selecting process parameters which minimize energy losses and increase process efficiency during IFW.

  6. Residual Stresses in Inertia-Friction-Welded Dissimilar High-Strength Steels

    Science.gov (United States)

    Moat, R. J.; Hughes, D. J.; Steuwer, A.; Iqbal, N.; Preuss, M.; Bray, S. E.; Rawson, M.

    2009-09-01

    The welding of dissimilar alloys is seen increasingly as a way forward to improve efficiencies in modern aeroengines, because it allows one to tailor varying material property demands across a component. Dissimilar inertia friction welding (IFW) of two high-strength steels, Aermet 100 and S/CMV, has been identified as a possible joint for rotating gas turbine components and the resulting welds are investigated in this article. In order to understand the impact of the welding process and predict the life expectancy of such structures, a detailed understanding of the residual stress fields present in the welded component is needed. By combining energy-dispersive synchrotron X-ray diffraction (EDSXRD) and neutron diffraction, it has been possible to map the variations in lattice spacing of the ferritic phase on both sides of two tubular Aermet 100-S/CMV inertia friction welds (as-welded and postweld heat-treated condition) with a wall thickness of 37 mm. Laboratory-based XRD measurements were required to take into account the variation in the strain-free d-spacing across the weld region. It was found that, in the heat-affected zone (HAZ) slightly away from the weld line, residual stress fields showed tensile stresses increasing most dramatically in the hoop direction toward the weld line. Closer to the weld line, in the plastically affected zone, a sharp drop in the residual stresses was observed on both sides, although more dramatically in the S/CMV. In addition to residual stress mapping, synchrotron XRD measurements were carried out to map microstructural changes in thin slices cut from the welds. By studying the diffraction peak asymmetry of the 200- α diffraction peak, it was possible to demonstrate that a martensitic phase transformation in the S/CMV is responsible for the significant stress reduction close to the weld line. The postweld heat treatment (PWHT) chosen to avoid any overaging of the Aermet 100 and to temper the S/CMV martensite resulted in little

  7. Finite Element Modeling of the Inertia Friction Welding of Dissimilar High-Strength Steels

    Science.gov (United States)

    Bennett, C. J.; Attallah, M. M.; Preuss, M.; Shipway, P. H.; Hyde, T. H.; Bray, S.

    2013-11-01

    Finite element (FE) process modeling of inertia friction welding between dissimilar high-strength steels, AerMet® 100 and SCMV, has been carried out using the DEFORM™-2D (v10.0) software. This model was validated against experimental data collected for a test weld performed between the materials; this included process data such as upset and rotational velocities as well as thermal data collected during the process using embedded thermocouples. The as-welded hoop residual stress from the FE model was also compared with experimental measurements taken on the welded component using synchrotron X-ray and neutron diffraction techniques. The modeling work considered the solid-state phase transformations which occur in the steels, and the trends in the residual stress data were well replicated by the model.

  8. Microstructural and Residual Stress Development due to Inertia Friction Welding in Ti-6246

    Science.gov (United States)

    Attallah, Moataz M.; Preuss, Michael; Boonchareon, Chatri; Steuwer, Axel; Daniels, John E.; Hughes, Darren J.; Dungey, Christopher; Baxter, Gavin J.

    2012-09-01

    A thorough investigation has been performed to assess the microstructural properties, mechanical properties (hardness and elastic modulus), and residual stress development in Ti-6Al-2Sn-4Zr-6Mo (Ti-6246) inertia friction welds in the as-welded and postweld heat-treated conditions. It was evident that the thermomechanical deformation in the weld region occurred above the β transus, forming dynamically recrystallized β grains and precipitating acicular α within the β grains, which resulted in a localized hardness increase. In the heat-affected zone, a ghost microstructure of the base metal formed because of the absence of sufficient time for diffusion, resulting in Mo segregation in the prior primary α plates. Energy-dispersive synchrotron X-ray diffraction and neutron diffraction were used to assess the residual stress development in the three principal directions. The variation in the unstrained lattice parameters across the weld regions was established by imposing a stress balance on the axial stress component in the radial direction. It was found that the maximum stresses occurred in the hoop direction, with significantly lower stresses present in the radial and axial directions. The maximum tensile hoop stresses were located at ~4 mm from the weld centerline and not at the dynamically recrystallized β-rich weld zone. This was associated with the α → β phase transformation and the subsequent acicular α precipitation within the region surrounding the weld centerline.

  9. Inertia

    Science.gov (United States)

    Murdin, P.

    2000-11-01

    The resistance of a massive body to any change in its velocity. Any body will continue in a state of rest or of uniform straight-line motion unless acted upon by a force. Thus a spacecraft, when its rocket motors are switched off, follows a ballistic trajectory because of its inertia. In Newton's second law of motion, the relationship between acceleration, a, of a body and the applied force, F, i...

  10. Site-Dependent Tension Properties of Inertia Friction-Welded Joints Made From Dissimilar Ni-based Superalloys

    Science.gov (United States)

    Senkov, O. N.; Mahaffey, D. W.; Semiatin, S. L.; Woodward, C.

    2015-03-01

    Microstructure, tensile properties, and fracture behavior of the inertia friction weld joints of dissimilar superalloys, cast Mar-M247 and wrought LSHR, were studied to assess the weld quality. Tensile tests were conducted at 23 and 704 °C on the samples containing different areas of the weld interface of the same welded material. The stress-strain curves were registered at different axial distances from the weld interface. In all tested samples, plastic deformation was localized on Mar-M247 side, outside the heat-affected zone (HAZ), and the resistance to plastic deformation of Mar-M247 increased with a decrease in the distance from the weld interface inside HAZ. Only elastic deformation occurred on the LSHR side. Fracture occurred on the Mar-M247 side, outside HAZ, or at the weld interface. In the latter case, welding defects in the form of clusters of nanometer-sized oxide and carbide particles were observed at the fracture surfaces. These results revealed that the IFW process is capable of producing the weld joints between Mar-M247 and LSHR with the fracture strength higher than that of Mar-M247. However, optimization of the IFW processing parameters is required to minimize clustering of oxide/carbide particles at the weld interface in this alloy pair.

  11. A Comparison of Residual Stress Development in Inertia Friction Welded Fine Grain and Coarse Grain Nickel-Base Superalloy

    Science.gov (United States)

    Iqbal, N.; Rolph, J.; Moat, R.; Hughes, D.; Hofmann, M.; Kelleher, J.; Baxter, G.; Withers, P. J.; Preuss, M.

    2011-12-01

    The effect of the base material microstructure on the development of residual stresses across the weld line in inertia friction welds (IFWs) of high-strength nickel-base superalloy RR1000 was studied using neutron diffraction. A comparison was carried out between tubular IFW specimens generated from RR1000 heat treated below (fine grain (FG) structure) and above (coarse grain (CG) structure) the γ'-solvus. Residual stresses were mapped in the as-welded (AW) condition and, after a postweld heat treatment (PWHT), optimized for maximum alloy strength. The highest tensile stresses were generally found in the hoop direction at the weld line near the inner diameter of the tubular-shaped specimens. A comparison between the residual stresses generated in FG and CG RR1000 suggests that the starting microstructure has little influence on the maximum residual stresses generated in the weld even though different levels of energy must be input to achieve a successful weld in each case. The residual stresses in the postweld heat treated samples were about 35 pct less than for the AW condition. Despite the fact that the high-temperature properties of the two parent microstructures are different, no significant differences in terms of stress relief were found between the FG and CG RR1000 IFWs. Since the actual weld microstructures of FG and CG RR1000 inertia welds are very similar, the results suggest that it is the weld microstructure and its associated high-temperature properties rather than the parent material that affects the overall weld stress distribution and its subsequent stress relief.

  12. Process Parameters for Banding 155-mm M483A1 Projectiles in High-Capacity Inertia Welding Machine.

    Science.gov (United States)

    1982-09-01

    injecting alcohol into them with a hypodermic needle. CHAMBERLAIN MANUFACTURING CORPORATION This was repeated several times to remove any oil and moisture...Chicago, Illinois: Formula 15440. A liquid solution of resins in aliphatic alcohols ; nonconductive and noncorrosive. Formula 7350. A liquid solution...and Leightont S. Sissom. Theory and Problema of teat Transfer (4ew York: 4crw-ttill, 1977). P. 217.Au issa Excess Temperature %T *T, - I*_. ’F Fig. 5

  13. THE COUPLED FEM ANALYSIS OF THE TRANSIENT TEMPERATURE FIELD DURING INERTIA FRICTION WELDING OF GH4169 ALLOY

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The inertia friction welding process is a non-linear process because of the interaction between the temperature field and the material properties as well as the friction force. A thermo-mechanical coupled finite element model is established to simulate the temperature field of this process. The transient temperature distribution during the inertia friction welding process of two similar workpieces of GH4169 alloy is calculated. The region of the circular cross-section of the workpiece is divided into a number of four-nodded isoparametric elements. In this model, the temperature dependent thermal properties, time dependent heat inputs, contact condition of welding interface,and deformation of the flash were considered. At the same time, the convection and radiation heat losses at the surface of the workpieces were also considered. A temperature data acquisition system was developed. The temperature at some position near the welding interface was measured using this system. The calculated temperature agrees well with the experimental data. The deformation of the flash and the factor affecting the temperature distribution at the welding interface are also discussed.

  14. Effect of Preheating on the Inertia Friction Welding of the Dissimilar Superalloys Mar-M247 and LSHR

    Science.gov (United States)

    Senkov, O. N.; Mahaffey, D. W.; Semiatin, S. L.

    2016-12-01

    Differences in the elevated temperature mechanical properties of cast Mar-M247 and forged LSHR make it difficult to produce sound joints of these alloys by inertia friction welding (IFW). While extensive plastic upset occurs on the LSHR side, only a small upset is typically developed on the Mar-M247 side. The limited plastic flow of Mar-M247 thus restricts the extent of "self-cleaning" and mechanical mixing of the mating surfaces, so that defects remain at the bond line after welding. In the present work, the effect of local preheating of Mar-M247 immediately prior to IFW on the welding behavior of Mar-M247/LSHR couples was determined. An increase in the preheat temperature enhanced the plastic flow of Mar-M247 during IFW, which resulted in extensive mechanical mixing with LSHR at the weld interface, the formation of extensive flash on both the Mar-M247 and LSHR sides, and a sound bond. Performed in parallel with the experimental work, finite-element-method (FEM) simulations showed that higher temperatures are achieved within the preheated sample during IFW relative to its non-preheated counterpart, and plastic flow is thus facilitated within it. Microstructure and post-weld mechanical properties of the welded samples were also established.

  15. Numerical Simulation of the Inertia Friction Welding Process of Dissimilar Materials

    Science.gov (United States)

    El-Hadek, Medhat A.

    2014-12-01

    Three-dimensional axisymmetric finite element analyses have been performed to analyze the coupled thermo-mechanical oscillatory transient problem of friction welding of two dissimilar hollow cylinders. The analysis included the effect of conduction and convection heat transfer implementing three independent variables specifically the welding time, the rotational velocity, and the thrust pressure. Experimental evaluation of the non-linear copper and Aluminum 6061 stress-strain responses, the thermal conductivities, and the specific heat coefficients were conducted using an environmental-controlled compartment for at least four different temperatures. These results were incorporated in the finite element model calculating a real joint transient temperature distribution and a full field view of the residual stresses in weldment. Variables of angular rotational velocity of (200, 400, and 600 rpm), thrust pressure of (10E5, 10E6, and 10E7 Pa), and total welding time of (1, 2, and 4 seconds) were used in the model simulation. The optimum welding conditions were selected using Taguchi method. Finally, the deformation shape predicted by the finite element simulations was compared to the deformations obtained by the experimental results.

  16. Friction Welding For Cladding Applications: Processing, Microstructure and Mechanical Properties of Inertia Friction Welds of Stainless Steel to Low Carbon Steel and Evaluation of Wrought and Welded Austenitic Stainless Steels for Cladding Applications in Acidchloride Service

    Science.gov (United States)

    Switzner, Nathan

    Friction welding, a solid-state joining method, is presented as a novel alternative process step for lining mild steel pipe and forged components internally with a corrosion resistant (CR) metal alloy for petrochemical applications. Currently, fusion welding is commonly used for stainless steel overlay cladding, but this method is costly, time-consuming, and can lead to disbonding in service due to a hard martensite layer that forms at the interface due to partial mixing at the interface between the stainless steel CR metal and the mild steel base. Firstly, the process parameter space was explored for inertia friction butt welding using AISI type 304L stainless steel and AISI 1018 steel to determine the microstructure and mechanical properties effects. A conceptual model for heat flux density versus radial location at the faying surface was developed with consideration for non-uniform pressure distribution due to frictional forces. An existing 1 D analytical model for longitudinal transient temperature distribution was modified for the dissimilar metals case and to account for material lost to the flash. Microstructural results from the experimental dissimilar friction welds of 304L stainless steel to 1018 steel were used to discuss model validity. Secondly, the microstructure and mechanical property implications were considered for replacing the current fusion weld cladding processes with friction welding. The nominal friction weld exhibited a smaller heat softened zone in the 1018 steel than the fusion cladding. As determined by longitudinal tensile tests across the bond line, the nominal friction weld had higher strength, but lower apparent ductility, than the fusion welds due to the geometric requirements for neck formation adjacent to a rigid interface. Martensite was identified at the dissimilar friction weld interface, but the thickness was smaller than that of the fusion welds, and the morphology was discontinuous due to formation by a mechanism of solid

  17. Study of thermometry for inertia friction welding%惯性摩擦焊测温研究

    Institute of Scientific and Technical Information of China (English)

    付春坤; 白钢; 王红宾

    2012-01-01

    Thermocouple instrument is an important thermometry instrument during the modern thermometiy practice,but because the proper hysteretic properties of thermocouple ,tbe accuracy of thermometiy can' t be improved.The article introduces a correction way based on the thermocouple thermometry principle during the practice of inertia friction welding,and the corrected result also has been cheeked by the infrared instrument It has a significance to improve the accuracy of thermometry.%热电偶测温是现代测温技术中的主要测温方法,但由于热电偶的滞后性,测温的准确度难以提高在基于惯性摩擦焊接动态测温试验基础上,提出了一种根据热电偶测温原理校正热电偶测温动态误差.通过红外议测温对校正结果进行了检验,结果较理想,对提高测温准确度具有一定的意义.

  18. GH4169惯性摩擦焊接过程动态再结晶组织演化的数值模拟%Numerical simulation of microstructure evolution for dynamic recrystallization of GH4169 during inertia friction welding

    Institute of Scientific and Technical Information of China (English)

    朱大喜; 张立文; 祝文卉; 曲伸

    2009-01-01

    利用MSC.Marc的热力耦合弹塑性有限元模拟技术,建立了GH4169环形件惯性摩擦焊接过程的二维热力耦合有限元模型.考虑到惯性摩擦焊接过程中的温度变化,采用叠加原理对Na YS建立的GH4169动态再结晶数学模型进行调整.借助MSc.Marc二次开发,将动态再结晶数学模型和有限元模型相结合,对惯性摩擦焊接过程中GH4169合金的动态再结晶组织演化进行数值模拟,得到了焊接过程中的动态再结晶分数和平均晶粒尺寸分布.对接头的宏观形貌和焊缝区的微观组织进行观察分析,发现模拟结果与实验结果吻合较好.%Using the coupled thermo-mechanical FEM technology of software MSC. Marc, a 2D thermo-mechanical coupled finite dement model for inertia friction welding process of GH4169 super-alloy ring parts was developed. Take into account of the non-isothermal condition during the inertia friction welding, the additivity rule was introduced to adapted the mathematical model for dynamic recrystallization of GH4169 established by Na Y S. By second-development of MSC. Marc, the mathematical model for dynamic recrystallization was combined with the finite model to simulate the microstructure evolution for dynamic recrystallization of GH4169 during the inertia friction welding process. The distributions of dynamic recrystallized fraction and average grain size during the welding process were obtained. The macrostructure of the friction welded joint and the microstructure of welding area was examined and analyzed, it was found that the simulation results agree well with the experimental results.

  19. 惯性释放法在大型复杂结构焊接变形预测中的应用%Application of Inertia Relief in the Prediction of Welding Deformation for Large Complex Structures

    Institute of Scientific and Technical Information of China (English)

    王阳; 罗宇; 陈震; 薛健

    2016-01-01

    Rigid-body motion boundary condition during computational welding mechanics, of which at least 6 degrees of freedom of welded structure will be fixed, is widely used to predict the welding distortion. However, because of the large scale and complexity of some structures, it is not advisable to consider the constraint for the unsupported welded structure during the computation. In this study, inertia relief method, the inertia force of the unconstrained structure is relieved to balance the exter-nal force, is proposed to investigate the welding deformation. Two methods are compared by predict-ing the welding deformation of a butt welded joint. Then, a hull block is taken as an example, simu-lations based on inherent deformation are conducted considering the inertia relief and rigid-body motion boundary conditions. By comparing the deformation of measured point, the computational re-sults by using inertia relief are the most approximate to measurement results compared to other cas-es, and it is more convenient to set the boundary condition using the proposed method which pro-vides an effective choice for the industrial application of welding structure deformation prediction.%在进行大型结构焊接变形有限元分析时,为了固定整体结构刚体位移必须施加不少于6个自由度的约束,但对于自由状态下的结构而言,如何施加这6个最少约束是非常的困难,长期以来是困扰研究人员的难题,也是焊接结构有限元分析在工业现场应用的一个瓶颈。所谓惯性释放法就是可以在不加约束的情况下模拟自由结构的变形。该文将在航海航空领域得到广泛应用的惯性释放法引入大型焊接结构变形分析,解决了自由状态下结构必须施加约束的问题。首先以典型的对接接头为例,比较了两种不同的约束方法之间的差别。然后通过一个典型的船体焊接变形预测的实例,验证了惯性释放法在大型结构中应用

  20. Polar inertia

    CERN Document Server

    Virilio, Paul

    1999-01-01

    Paul Virilio demonstrates how technology has made inertia the defining condition of modernity. An instantaneous present has replaced space and the sovereignty of territory - everything happens without the need to go anywhere.

  1. Welding.

    Science.gov (United States)

    Cowan, Earl; And Others

    The curriculum guide for welding instruction contains 16 units presented in six sections. Each unit is divided into the following areas, each of which is color coded: terminal objectives, specific objectives, suggested activities, and instructional materials; information sheet; transparency masters; assignment sheet; test; and test answers. The…

  2. Future High Capacity Backbone Networks

    DEFF Research Database (Denmark)

    Wang, Jiayuan

    This thesis - Future High Capacity Backbone Networks - deals with the energy efficiency problems associated with the development of future optical networks. In the first half of the thesis, novel approaches for using multiple/single alternative energy sources for improving energy efficiency...... the context of the integrated control plane structure. Results show improvements of energy efficiency over three types of traffic, while still keeping acceptable QoS levels for high priority traffic....

  3. Inertia and Decision Making.

    Science.gov (United States)

    Alós-Ferrer, Carlos; Hügelschäfer, Sabine; Li, Jiahui

    2016-01-01

    Decision inertia is the tendency to repeat previous choices independently of the outcome, which can give rise to perseveration in suboptimal choices. We investigate this tendency in probability-updating tasks. Study 1 shows that, whenever decision inertia conflicts with normatively optimal behavior (Bayesian updating), error rates are larger and decisions are slower. This is consistent with a dual-process view of decision inertia as an automatic process conflicting with a more rational, controlled one. We find evidence of decision inertia in both required and autonomous decisions, but the effect of inertia is more clear in the latter. Study 2 considers more complex decision situations where further conflict arises due to reinforcement processes. We find the same effects of decision inertia when reinforcement is aligned with Bayesian updating, but if the two latter processes conflict, the effects are limited to autonomous choices. Additionally, both studies show that the tendency to rely on decision inertia is positively associated with preference for consistency.

  4. High capacity optical links for datacentre connectivity

    DEFF Research Database (Denmark)

    Tafur Monroy, Idelfonso; Usuga, Mario; Vegas Olmos, Juan José

    There is a timely and growing demand for high capacity optical data transport solutions to provide connectivity inside data centres and between data centres located at different geographical locations. The requirements for reach are in the order of 2 km for intra-datacentre and up to 100 km for i...

  5. A high capacity 3D steganography algorithm.

    Science.gov (United States)

    Chao, Min-Wen; Lin, Chao-hung; Yu, Cheng-Wei; Lee, Tong-Yee

    2009-01-01

    In this paper, we present a very high-capacity and low-distortion 3D steganography scheme. Our steganography approach is based on a novel multilayered embedding scheme to hide secret messages in the vertices of 3D polygon models. Experimental results show that the cover model distortion is very small as the number of hiding layers ranges from 7 to 13 layers. To the best of our knowledge, this novel approach can provide much higher hiding capacity than other state-of-the-art approaches, while obeying the low distortion and security basic requirements for steganography on 3D models.

  6. High Capacity Radio over Fiber Transmission Links

    DEFF Research Database (Denmark)

    Caballero Jambrina, Antonio

    . This achievement has satisfied the requirements on transmission robustness and high capacity of next generation hybrid optical fibre-wireless networks. One important contribution of this thesis is the novel concept of photonic downconversion with free-running pulsed laser source for phase modulated Radio...... confirmed that this configuration provides high linear end-to-end transmission links and is capable of transparent transport of high spectral efficient modulation formats. Furthermore, this thesis introduces a novel approach for the generation and detection of high speed wireless signals in mm...... of the writing of this thesis. In conclusion, the results presented in this thesis demonstrate the feasibility of photonic technologies for the generation, distribution and detection of high speed wireless signals. Furthermore, it opens the prospects for next generation hybrid wireless-wired access networks...

  7. Building the UPPA high capacity tensiometer

    Directory of Open Access Journals (Sweden)

    Mendes Joao

    2016-01-01

    Full Text Available High capacity tensiometers (HCTs are sensors capable of directly measuring tensile pore water pressure (suction in soils. HCTs are typically composed of a casing that encapsulates a high air entry value ceramic filter, a water reservoir and a pressure sensing element. Since the creation of the first HCT by Ridley and Burland in 1993 at Imperial College London, HCTs have been almost exclusively built and used in academic research. The limited use in industrial applications can be explained by a lack of unsaturated soil mechanics knowledge among engineering practitioners but also by the technical difficulties associated to the direct measurement of tensile water pressures beyond the cavitation limit of -100kPa. In this paper, we present the recent design and manufacture of a new HCT at the Université de Pau et des Pays de l’Adour (UPPA in France. Different prototypes were tried by changing the main components of the device including the type of ceramic filter, pressure transducer and geometry of the external casing. In particular, two ceramic filters of distinct porosity, three pressure transducers with distinct materials/geometries and four casing designs were tested.

  8. Towards green high capacity optical networks

    Science.gov (United States)

    Glesk, I.; Mohd Warip, M. N.; Idris, S. K.; Osadola, T. B.; Andonovic, I.

    2012-02-01

    The demand for fast, secure, energy efficient high capacity networks is growing. It is fuelled by transmission bandwidth needs which will support among other things the rapid penetration of multimedia applications empowering smart consumer electronics and E-businesses. All the above trigger unparallel needs for networking solutions which must offer not only high-speed low-cost "on demand" mobile connectivity but should be ecologically friendly and have low carbon footprint. The first answer to address the bandwidth needs was deployment of fibre optic technologies into transport networks. After this it became quickly obvious that the inferior electronic bandwidth (if compared to optical fiber) will further keep its upper hand on maximum implementable serial data rates. A new solution was found by introducing parallelism into data transport in the form of Wavelength Division Multiplexing (WDM) which has helped dramatically to improve aggregate throughput of optical networks. However with these advancements a new bottleneck has emerged at fibre endpoints where data routers must process the incoming and outgoing traffic. Here, even with the massive and power hungry electronic parallelism routers today (still relying upon bandwidth limiting electronics) do not offer needed processing speeds networks demands. In this paper we will discuss some novel unconventional approaches to address network scalability leading to energy savings via advance optical signal processing. We will also investigate energy savings based on advanced network management through nodes hibernation proposed for Optical IP networks. The hibernation reduces the network overall power consumption by forming virtual network reconfigurations through selective nodes groupings and by links segmentations and partitionings.

  9. Jet propulsion without inertia

    CERN Document Server

    Spagnolie, Saverio E

    2010-01-01

    A body immersed in a highly viscous fluid can locomote by drawing in and expelling fluid through pores at its surface. We consider this mechanism of jet propulsion without inertia in the case of spheroidal bodies, and derive both the swimming velocity and the hydrodynamic efficiency. Elementary examples are presented, and exact axisymmetric solutions for spherical, prolate spheroidal, and oblate spheroidal body shapes are provided. In each case, entirely and partially porous (i.e. jetting) surfaces are considered, and the optimal jetting flow profiles at the surface for maximizing the hydrodynamic efficiency are determined computationally. The maximal efficiency which may be achieved by a sphere using such jet propulsion is 12.5%, a significant improvement upon traditional flagella-based means of locomotion at zero Reynolds number. Unlike other swimming mechanisms which rely on the presentation of a small cross section in the direction of motion, the efficiency of a jetting body at low Reynolds number increas...

  10. FLUXES FOR MECHANIZED ELECTRIC WELDING,

    Science.gov (United States)

    WELDING FLUXES, WELDING ), (* WELDING , WELDING FLUXES), ARC WELDING , WELDS, STABILITY, POROSITY, WELDING RODS, STEEL, CERAMIC MATERIALS, FLUXES(FUSION), TITANIUM ALLOYS, ALUMINUM ALLOYS, COPPER ALLOYS, ELECTRODEPOSITION

  11. Dynamic Inertia Measurement Method Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Critically important inertia measurements are complex and expensive to obtain due to the extensive fixturing and custom instrumentation of conventional...

  12. Welding Curriculum.

    Science.gov (United States)

    Alaska State Dept. of Education, Juneau. Div. of Adult and Vocational Education.

    This competency-based curriculum guide is a handbook for the development of welding trade programs. Based on a survey of Alaskan welding employers, it includes all competencies a student should acquire in such a welding program. The handbook stresses the importance of understanding the principles associated with the various elements of welding.…

  13. Advanced Welding Concepts

    Science.gov (United States)

    Ding, Robert J.

    2010-01-01

    Four advanced welding techniques and their use in NASA are briefly reviewed in this poster presentation. The welding techniques reviewed are: Solid State Welding, Friction Stir Welding (FSW), Thermal Stir Welding (TSW) and Ultrasonic Stir Welding.

  14. Radiation Tolerant, High Capacity Non-Volatile Memory Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The need for reliable, high capacity, radiation tolerant nonvolatile memory exists in many Human space flight applications. Most projects rely on COTS hardware for a...

  15. STUDY ON DYNAMIC J-INTEGRAL OF MECHANICAL HETEROGENEOUS WELDED JOINT

    Institute of Scientific and Technical Information of China (English)

    F.Q. Tian; D.Y. He; X.Y. Li; Y.W. Shi; D. Zhang

    2004-01-01

    Welded joint is a mechanical heterogeneous body, and mechanical heterogeneity has great effect on dynamic fracture behaviour of welded joints. In the present investigation, dynamic response curve and dynamic J-integral of practical undermatched welded joint and whole base and whole weld three-point-bend (TPB) models containing longitudinal crack are computed. Dynamic J-integral is evaluated using virtual crack extension (VCE) method and the computation is performed using MARC finite element code. Because of the effect of inertia,dynamic load response curve of computed model waves periodically. Dynamic J-integral evaluated by VCE method is path independent. The effect of inertia has little influence on dynamic J-integral curve. The value of dynamic J-integral of undermatched welded joint is lower than that of whole base metal and higher than that of whole weld metal. The results establish the foundation of safety evaluation for dynamic loaded welded structures.

  16. Neutron star moments of inertia

    Science.gov (United States)

    Ravenhall, D. G.; Pethick, C. J.

    1994-01-01

    An approximation for the moment of inertia of a neutron star in terms of only its mass and radius is presented, and insight into it is obtained by examining the behavior of the relativistic structural equations. The approximation is accurate to approximately 10% for a variety of nuclear equations of state, for all except very low mass stars. It is combined with information about the neutron-star crust to obtain a simple expression (again in terms only of mass and radius) for the fractional moment of inertia of the crust.

  17. Measuring the Moment of Inertia

    Science.gov (United States)

    Lehmberg, George L.

    1978-01-01

    Two physics experiments are described, One, involving a laboratory cart accelerated along a level surface, examines the concept of inertial mass in translation and the other, using a solid cylinder, measures the moment of inertia of a wheel. Equations and illustrations are included. (MA)

  18. Moment of Inertia by Differentiation

    Science.gov (United States)

    Rizcallah, Joseph A.

    2015-01-01

    The calculation of the moment of inertia of an extended body, as presented in standard introductory-level textbooks, involves the evaluation of a definite integral--an operation often not fully mastered by beginners, let alone the conceptual difficulties it presents, even to the advanced student, in understanding and setting up the integral in the…

  19. Welding Technician

    Science.gov (United States)

    Smith, Ken

    2009-01-01

    About 95% of all manufactured goods in this country are welded or joined in some way. These welded products range in nature from bicycle handlebars and skyscrapers to bridges and race cars. The author discusses what students need to know about careers for welding technicians--wages, responsibilities, skills needed, career advancement…

  20. High capacity anode materials for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, Herman A.; Anguchamy, Yogesh Kumar; Deng, Haixia; Han, Yongbon; Masarapu, Charan; Venkatachalam, Subramanian; Kumar, Suject

    2015-11-19

    High capacity silicon based anode active materials are described for lithium ion batteries. These materials are shown to be effective in combination with high capacity lithium rich cathode active materials. Supplemental lithium is shown to improve the cycling performance and reduce irreversible capacity loss for at least certain silicon based active materials. In particular silicon based active materials can be formed in composites with electrically conductive coatings, such as pyrolytic carbon coatings or metal coatings, and composites can also be formed with other electrically conductive carbon components, such as carbon nanofibers and carbon nanoparticles. Additional alloys with silicon are explored.

  1. Resistance welding

    DEFF Research Database (Denmark)

    Bay, Niels; Zhang, Wenqi; Rasmussen, Mogens H.

    2003-01-01

    Resistance welding comprises not only the well known spot welding process but also more complex projection welding operations, where excessive plastic deformation of the weld point may occur. This enables the production of complex geometries and material combinations, which are often not possible...... to weld by traditional spot welding operations. Such joining processes are, however, not simple to develop due to the large number of parameters involved. Development has traditionally been carried out by large experimental investigations, but the development of a numerical programme system has changed...... this enabling prediction of the welding performance in details. The paper describes the programme in short and gives examples on industrial applications. Finally investigations of causes for failure in a complex industrial joint of two dissimilar metals are carried out combining numerical modelling...

  2. Resistance welding

    DEFF Research Database (Denmark)

    Bay, Niels; Zhang, Wenqi; Rasmussen, Mogens H.

    2003-01-01

    this enabling prediction of the welding performance in details. The paper describes the programme in short and gives examples on industrial applications. Finally investigations of causes for failure in a complex industrial joint of two dissimilar metals are carried out combining numerical modelling......Resistance welding comprises not only the well known spot welding process but also more complex projection welding operations, where excessive plastic deformation of the weld point may occur. This enables the production of complex geometries and material combinations, which are often not possible...... to weld by traditional spot welding operations. Such joining processes are, however, not simple to develop due to the large number of parameters involved. Development has traditionally been carried out by large experimental investigations, but the development of a numerical programme system has changed...

  3. Micro-machined high capacity silicon load cells

    NARCIS (Netherlands)

    Zwijze, A.F.

    2000-01-01

    The aim of the research presented in this thesis is to improve the performance of high capacity conventional load cells or force sensors by using silicon as the base material. Silicon is used because it offers the possibility of realising small, light, low cost and high performance mechanical sensor

  4. Caffeine gum minimizes sleep inertia.

    Science.gov (United States)

    Newman, Rachel A; Kamimori, Gary H; Wesensten, Nancy J; Picchioni, Dante; Balkin, Thomas J

    2013-02-01

    Naps are an effective strategy for maintaining alertness and cognitive performance; however, upon abrupt wakening from naps, sleep inertia (temporary performance degradation) may ensue. In the present study, attenuation of post-nap sleep inertia was attempted by administration of caffeine gum. Using a double-blind, placebo-controlled crossover design, 15 healthy, non-smoking adults were awakened at 1 hr. and again at 6 hr. after lights out (0100 and 0600, respectively) and were immediately administered a gum pellet containing 100 mg of caffeine or placebo. A 5-min. psychomotor vigilance task was administered at 0 min., 6 min., 12 min., and 18 min. post-awakening. At 0100, response speed with caffeine was significantly better at 12 min. and 18 min. post-awakening compared to placebo; at 0600, caffeine's effects were evident at 18 min. post-awakening. Caffeinated gum is a viable means of rapidly attenuating sleep inertia, suggesting that the adenosine receptor system is involved in sleep maintenance.

  5. Hiding robot inertia using resonance.

    Science.gov (United States)

    Vallery, Heike; Duschau-Wicke, Alexander; Riener, Robert

    2010-01-01

    To enable compliant training modes with a rehabilitation robot, an important prerequisite is that any undesired human-robot interaction forces caused by robot dynamics must be avoided, either by an appropriate mechanical design or by compensating control strategies. Our recently proposed control scheme of "Generalized Elasticities" employs potential fields to compensate for robot dynamics, including inertia, beyond what can be done using closed-loop force control. In this paper, we give a simple mechanical equivalent using the example of the gait rehabilitation robot Lokomat. The robot consists of an exoskeleton that is attached to a frame around the patient's pelvis. This frame is suspended by a springloaded parallelogram structure. The mechanism allows vertical displacement while providing almost constant robot gravity compensation. However, inertia of the device when the patient's pelvis moves up and down remains a source of large interaction forces, which are reflected in increased ground reaction forces. Here, we investigate an alternative suspension: To hide not only gravity, but also robot inertia during vertical pelvis motion, we suspend the robot frame by a stiff linear spring that allows the robot to oscillate vertically at an eigenfrequency close to the natural gait frequency. This mechanism reduces human-robot interaction forces, which is demonstrated in pilot experimental results.

  6. Soldadura (Welding). Spanish Translations for Welding.

    Science.gov (United States)

    Hohhertz, Durwin

    Thirty transparency masters with Spanish subtitles for key words are provided for a welding/general mechanical repair course. The transparency masters are on such topics as oxyacetylene welding; oxyacetylene welding equipment; welding safety; different types of welds; braze welding; cutting torches; cutting with a torch; protective equipment; arc…

  7. WELDING TORCH

    Science.gov (United States)

    Correy, T.B.

    1961-10-01

    A welding torch into which water and inert gas are piped separately for cooling and for providing a suitable gaseous atmosphere is described. A welding electrode is clamped in the torch by a removable collet sleeve and a removable collet head. Replacement of the sleeve and head with larger or smaller sleeve and head permits a larger or smaller welding electrode to be substituted on the torch. (AEC)

  8. Evaluation of weld porosity in laser beam seam welds: optimizing continuous wave and square wave modulated processes.

    Energy Technology Data Exchange (ETDEWEB)

    Ellison, Chad M. (Honeywell FM& T, Kansas City, MO); Perricone, Matthew; Faraone, Kevin M. (Honeywell FM& T, Kansas City, MO); Roach, Robert Allen; Norris, Jerome T.

    2007-02-01

    Nd:YAG laser joining is a high energy density (HED) process that can produce high-speed, low-heat input welds with a high depth-to-width aspect ratio. This is optimized by formation of a ''keyhole'' in the weld pool resulting from high vapor pressures associated with laser interaction with the metallic substrate. It is generally accepted that pores form in HED welds due to the instability and frequent collapse of the keyhole. In order to maintain an open keyhole, weld pool forces must be balanced such that vapor pressure and weld pool inertia forces are in equilibrium. Travel speed and laser beam power largely control the way these forces are balanced, as well as welding mode (Continuous Wave or Square Wave) and shielding gas type. A study into the phenomenon of weld pool porosity in 304L stainless steel was conducted to better understand and predict how welding parameters impact the weld pool dynamics that lead to pore formation. This work is intended to aid in development and verification of a finite element computer model of weld pool fluid flow dynamics being developed in parallel efforts and assist in weld development activities for the W76 and future RRW programs.

  9. Recycling rice husks for high-capacity lithium battery anodes.

    Science.gov (United States)

    Jung, Dae Soo; Ryou, Myung-Hyun; Sung, Yong Joo; Park, Seung Bin; Choi, Jang Wook

    2013-07-23

    The rice husk is the outer covering of a rice kernel and protects the inner ingredients from external attack by insects and bacteria. To perform this function while ventilating air and moisture, rice plants have developed unique nanoporous silica layers in their husks through years of natural evolution. Despite the massive amount of annual production near 10(8) tons worldwide, so far rice husks have been recycled only for low-value agricultural items. In an effort to recycle rice husks for high-value applications, we convert the silica to silicon and use it for high-capacity lithium battery anodes. Taking advantage of the interconnected nanoporous structure naturally existing in rice husks, the converted silicon exhibits excellent electrochemical performance as a lithium battery anode, suggesting that rice husks can be a massive resource for use in high-capacity lithium battery negative electrodes.

  10. Moments of inertia of relativistic magnetized stars

    OpenAIRE

    Konno, K

    2001-01-01

    We consider principal moments of inertia of axisymmetric, magnetically deformed stars in the context of general relativity. The general expression for the moment of inertia with respect to the symmetric axis is obtained. The numerical estimates are derived for several polytropic stellar models. We find that the values of the principal moments of inertia are modified by a factor of 2 at most from Newtonian estimates.

  11. Toward a definition of colonic inertia

    Institute of Scientific and Technical Information of China (English)

    Gabrio Bassotti; Giuseppe de Roberto; Luca Sediari; Antonio Morelli

    2004-01-01

    Chronic constipation is a relatively frequent symptom; among its subtypes, the so called-colonic inertia represents a disease condition that is often considered for surgery. However, to date, there has been no agreement on definition of colonic inertia, and a literature review showed that this definition was given to numerous entities that differ from each other.In this paper these concepts are reviewed and a more stringent definition of colonic inertia is proposed.

  12. Virtual inertia for variable speed wind turbines

    DEFF Research Database (Denmark)

    Zeni, Lorenzo; Rudolph, Andreas Jakob; Münster-Swendsen, Janus

    2013-01-01

    Inertia provision for frequency control is among the ancillary services that different national grid codes will likely require to be provided by future wind turbines. The aim of this paper is analysing how the inertia response support from a variable speed wind turbine (VSWT) to the primary...... frequency control of a power system can be enhanced. Unlike fixed speed wind turbines, VSWTs do not inherently contribute to system inertia, as they are decoupled from the power system through electronic converters. Emphasis in this paper is on how to emulate VSWTs inertia using control of the power...

  13. The growth of children's moment of inertia.

    Science.gov (United States)

    Jensen, R K

    1986-08-01

    As children grow, their moments of inertia increase. The magnitude and timing of these changes can affect the rotations of the body. The present study evaluated inter-individual differences in the transverse centroidal moment of inertia for 12 boys between 5 and 16 yr, using intra-individual data from three successive years. Segmental masses and moments of inertia were estimated using the elliptical zone model and the model then repositioned into two configurations: a layout position from a back handspring and a tuck position from a back somersault. In each case, the mass centroid and the moment of inertia about the transverse axis were calculated. With growth indexed by age, it was shown that the rate of change increases with age. For the children 10 yr and younger, the rate of change of moment of inertia was approximately 30% of the rate for the older children. Also, at each age level, there was a wide range of moments of inertia. In order to improve the prediction of moment of inertia, height and mass were tried as predictors with a noticeable improvement in correlation and linearity. The best predictor, however, was found to be the product of mass and height squared (M X H2) with correlations of 0.99 and 0.97. It is suggested that, because of the effects of growth on the moment of inertia. M X H2 could be used in conjunction with age in order to better appreciate the potential effects of change of moment of inertia.

  14. High-capacity nanocarbon anodes for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Haitao; Sun, Xianzhong; Zhang, Xiong; Lin, He; Wang, Kai; Ma, Yanwei, E-mail: ywma@mail.iee.ac.cn

    2015-02-15

    Highlights: • The nanocarbon anodes in lithium-ion batteries deliver a high capacity of ∼1100 mA h g{sup −1}. • The nanocarbon anodes exhibit excellent cyclic stability. • A novel structure of carbon materials, hollow carbon nanoboxes, has potential application in lithium-ion batteries. - Abstract: High energy and power density of secondary cells like lithium-ion batteries become much more important in today’s society. However, lithium-ion battery anodes based on graphite material have theoretical capacity of 372 mA h g{sup −1} and low charging-discharging rate. Here, we report that nanocarbons including mesoporous graphene (MPG), carbon tubular nanostructures (CTN), and hollow carbon nanoboxes (HCB) are good candidate for lithium-ion battery anodes. The nanocarbon anodes have high capacity of ∼1100, ∼600, and ∼500 mA h g{sup −1} at 0.1 A g{sup −1} for MPG, CTN, and HCB, respectively. The capacity of 181, 141, and 139 mA h g{sup −1} at 4 A g{sup −1} for MPG, CTN, and HCB anodes is retained. Besides, nanocarbon anodes show high cycling stability during 1000 cycles, indicating formation of a passivating layer—solid electrolyte interphase, which support long-term cycling. Nanocarbons, constructed with graphene layers which fulfill lithiation/delithiation process, high ratio of graphite edge structure, and high surface area which facilitates capacitive behavior, deliver high capacity and improved rate-capability.

  15. Cycloaddition in peptides for high-capacity optical storage

    DEFF Research Database (Denmark)

    Lohse, Brian; Berg, Rolf Henrik; Hvilsted, Søren

    2006-01-01

    Photodimerization of chromophores attached to a short peptide chain is investigated for high-capacity optical digital storage with UV lasers. The length and rigidity of the peptide chain assure an optimal distance and orientation of the chromophores for effective photodimerization. Using a theory...... developed by Tomlinson, the absorption cross section for the dimerization process in a uracil-ornithine-based hexamer is determined to be 9 x 10(-20) cm(2). A large change in the transmission due to irradiation in the UV area may make it possible to realize multilevel storage in a thin film of the peptides....

  16. High capacity 30 K remote helium cooling loop

    Science.gov (United States)

    Trollier, T.; Tanchon, J.; Icart, Y.; Ravex, A.

    2014-01-01

    Absolut System has built several 50 K remote helium cooling loops used as high capacity and very low vibration cooling source into large wavelength IR detectors electro-optical characterization test benches. MgB2 based superconducting electro-technical equipment's under development require also distributed high cooling power in the 20-30 K temperature range. Absolut System has designed, manufactured and tested a high capacity 30 K remote helium cooling loop. The equipment consists of a CRYOMECH AL325 type cooler, a CP830 type compressor package used as room temperature circulator and an intermediate LN2 bath cooling used between two recuperator heat exchangers (300 K-77 K and 77 K-20 K). A cooling capacity of 30 W @ 20 K or 80 W @ 30 K has been demonstrated on the application heat exchanger, with a 4-meter remote distance ensured by a specifically designed gas circulation flexible line. The design and the performance will be reported in this paper.

  17. High-capacity hydrogen storage in Al-adsorbed graphene

    Science.gov (United States)

    Ao, Z. M.; Peeters, F. M.

    2010-05-01

    A high-capacity hydrogen storage medium—Al-adsorbed graphene—is proposed based on density-functional theory calculations. We find that a graphene layer with Al adsorbed on both sides can store hydrogen up to 13.79wt% with average adsorption energy -0.193eV/H2 . Its hydrogen storage capacity is in excess of 6wt% , surpassing U. S. Department of Energy (DOE’s) target. Based on the binding-energy criterion and molecular-dynamics calculations, we find that hydrogen storage can be recycled at near ambient conditions. This high-capacity hydrogen storage is due to the adsorbed Al atoms that act as bridges to link the electron clouds of the H2 molecules and the graphene layer. As a consequence, a two-layer arrangement of H2 molecules is formed on each side of the Al-adsorbed graphene layer. The H2 concentration in the hydrogen storage medium can be measured by the change in the conductivity of the graphene layer.

  18. INERTIA SETS OF SYMMETRIC SIGN PATTERN MATRICES

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A sign pattern matrix is a matrixwhose entries are from the set {+ ,- ,0}. The symmetric sign pattern matrices that require unique inertia have recently been characterized. The purpose of this paper is to more generally investigate the inertia sets of symmetric sign pattern matrices. In particular, nonnegative fri-diagonal sign patterns and the square sign pattern with all + entries are examined. An algorithm is given for generating nonnegative real symmetric Toeplitz matrices with zero diagonal of orders n≥3 which have exactly two negative eigenvalues. The inertia set of the square pattern with all + off-diagonal entries and zero diagonal entries is then analyzed. The types of inertias which can be in the inertia set of any sign pattern are also obtained in the paper. Specifically, certain compatibility and consecutiveness properties are established.

  19. Grooving corrosion of seam welded oil pipelines

    Directory of Open Access Journals (Sweden)

    Mohamed Hanafy El-Sayed

    2014-10-01

    Full Text Available 24” pipeline carrying oil was failed in the form of longitudinal crack at the 6 O’clock position resulting in oil spill. The failed pipe was investigated to reveal the main cause of its failure. The procedure of investigation was built on studying the intact pipe, rupture area, parent material, and intact weld. Results of chemical analysis, mechanical properties, and microstructure of the pipe material were confirmed with the specified standard. Cracks were originated from weld defected sites, initiated by grooving corrosion, propagated by inertia at the normal designed pressure condition, and stopped when stress relief is attained. It is recommended to use high quality ERW pipe, with its seam weld line positioned around the 12 O’clock during installation, to minimize and decelerate grooving corrosion. It is also important to perform regular or routine inspection, on suitable intervals, determined by past experience.

  20. ELECTRIC WELDING EQUIPMENT AND AUTOMATION OF WELDING IN CONSTRUCTION,

    Science.gov (United States)

    WELDING , *ARC WELDING , AUTOMATION, CONSTRUCTION, INDUSTRIES, POWER EQUIPMENT, GENERATORS, POWER TRANSFORMERS, RESISTANCE WELDING , SPOT WELDING , MACHINES, AUTOMATIC, STRUCTURES, WIRING DIAGRAMS, USSR.

  1. Syllabus in Trade Welding.

    Science.gov (United States)

    New York State Education Dept., Albany. Bureau of Secondary Curriculum Development.

    The syllabus outlines material for a course two academic years in length (minimum two and one-half hours daily experience) leading to entry-level occupational ability in several welding trade areas. Fourteen units covering are welding, gas welding, oxyacetylene welding, cutting, nonfusion processes, inert gas shielded-arc welding, welding cast…

  2. High Capacity and Resistance to Additive Noise Audio Steganography Algorithm

    Directory of Open Access Journals (Sweden)

    Haider Ismael Shahadi

    2011-09-01

    Full Text Available Steganography is the art of message hiding in a cover signal without attracting attention. The requirements of the good steganography algorithm are security, capacity, robustness and imperceptibility, all them are contradictory, therefore, satisfying all together is not easy especially in audio cover signal because human auditory system (HAS has high sensitivity to audio modification. In this paper, we proposed a high capacity audio steganography algorithm with good resistance to additive noise. The proposed algorithm is based on wavelet packet transform and blocks matching. It has capacity above 35% of the input audio file size with acceptable signal to noise ratio. Also, it is resistance to additive Gaussian noise to about 25 db. Furthermore, the reconstruction of actual secret messages does not require the original cover audio signal.

  3. Hydrophilic carbon clusters as therapeutic, high capacity antioxidants

    Science.gov (United States)

    Samuel, Errol L. G.; Duong, MyLinh T.; Bitner, Brittany R.; Marcano, Daniela C.; Tour, James M.; Kent, Thomas A.

    2014-01-01

    Oxidative stress reflects an excessive accumulation of reactive oxygen species (ROS) and is a hallmark of several acute and chronic human pathologies. While many antioxidants have been investigated, the majority have demonstrated poor efficacy in clinical trials. Here, we discuss limitations of current antioxidants and describe a new class of nanoparticle antioxidants, poly(ethylene glycol)-functionalized hydrophilic carbon clusters (PEG-HCCs). PEG-HCCs show high capacity to annihilate ROS such as superoxide and hydroxyl radicals, show no reactivity toward nitric oxide, and can be functionalized with targeting moieties without loss of activity. Given these properties, we propose that PEG-HCCs offer an exciting new area of study for treatment of numerous ROS-induced human pathologies. PMID:25175886

  4. Holographic memory module with ultra-high capacity and throughput

    Energy Technology Data Exchange (ETDEWEB)

    Vladimir A. Markov, Ph.D.

    2000-06-04

    High capacity, high transfer rate, random access memory systems are needed to archive and distribute the tremendous volume of digital information being generated, for example, the human genome mapping and online libraries. The development of multi-gigabit per second networks underscores the need for next-generation archival memory systems. During Phase I we conducted the theoretical analysis and accomplished experimental tests that validated the key aspects of the ultra-high density holographic data storage module with high transfer rate. We also inspected the secure nature of the encoding method and estimated the performance of full-scale system. Two basic architectures were considered, allowing for reversible compact solid-state configuration with limited capacity, and very large capacity write once read many memory system.

  5. Inertia from an asymmetric Casimir effect

    CERN Document Server

    McCulloch, M E

    2013-01-01

    The property of inertia has never been fully explained. A model for inertia (MiHsC or quantised inertia) has been suggested that assumes that 1) inertia is due to Unruh radiation and 2) this radiation is subject to a Hubble-scale Casimir effect. This model has no adjustable parameters and predicts the cosmic acceleration, and galaxy rotation without dark matter, suggesting that Unruh radiation indeed causes inertia, but the exact mechanism by which it does this has not been specified. The mechanism suggested here is that when an object accelerates, for example to the right, a dynamical (Rindler) event horizon forms to its left, reducing the Unruh radiation on that side by a Rindler-scale Casimir effect whereas the radiation on the other side is only slightly reduced by a Hubble-scale Casimir effect. This produces an imbalance in the radiation pressure on the object, and a net force that always opposes acceleration, like inertia. A formula for inertia is derived, and an experimental test is suggested.

  6. Welded Kimberlite?

    Science.gov (United States)

    van Straaten, B. I.; Kopylova, M. G.; Russell, J. K.; Scott Smith, B. H.

    2009-05-01

    Welding of pyroclastic deposits generally involves the sintering of hot glassy vesicular particles and requires the presence of a load and/or high temperatures. Welding can occur on various scales as observed in large welded pyroclastic flows, in small-volume agglutinated spatter rims, or as in coalesced clastogenic lava flows. In all these examples welding occurs mainly by reduction or elimination of porosity within the vesicular clasts and/or inter-clast pore space. The end result of welding in pyroclastic deposits is to produce dense, massive, coherent deposits. Here, we present a possible new end-member of the welding process: welding of non- vesicular pyroclasts in intra-crater kimberlite deposits. Kimberlite melt is a low-viscosity liquid carrying abundant crystals. Because of this, kimberlite eruptions generally produce non-vesicular pyroclasts. During welding, these pyroclast cannot deform by volume reduction to form typical fiamme. As a result, welding and compaction in kimberlites proceeds via the reduction of inter-clast pore space alone. The lack of porous pyroclasts limits the maximum amount of volumetric strain within pyroclastic kimberlite deposits to about 30%. This value is substantially lower than the limiting values for welding of more common felsic pyroclastic flows. The lower limit for volumetric strain in welded kimberlite deposits severely restricts the development of a fabric. In addition, pyroclastic kimberlite deposits commonly feature equant-shaped pyroclasts, and equant-shaped crystals. This, in turn, limits the visibility of the results of compaction and pore space reduction, as there are few deformable markers and elongate rigid markers that are able to record the strain during compaction. These features, together with the low viscosity of kimberlite magma and the stratigraphic position of these kimberlite deposits within the upper reaches of the volcanic conduit, call for careful interpretation of coherent-looking rocks in these

  7. A Reevaluation of the Attentional Inertia Concept

    NARCIS (Netherlands)

    W.J.M.I. Verbeke (Willem)

    1992-01-01

    textabstractAnderson's (1983) theory about children's attention behavior during television viewing hypothesizes that attention behavior is affected by positive feedback (the inertia hypothesis) and the degree to which a child understands the television program. During an experiment, neither

  8. Moment of Inertia of a Physical Pendulum.

    Science.gov (United States)

    Reidl, Charles J., Jr.

    1996-01-01

    Presents a simple and inexpensive procedure for determining the moment of inertia of a physical pendulum both experimentally and analytically. The simplicity of the apparatus enables students to easily change parameters and obtain a wide variety of measurements. (JRH)

  9. Tinker Toys Have Their Moments of Inertia.

    Science.gov (United States)

    Taylor, Kenneth Neal

    1983-01-01

    Describes use of Tinker Toys in several moment of inertia laboratory experiments at the advanced high school or introductory college levels. Includes procedures to be followed, arrangements of the Tinker Toy parts during experiments, and typical student data obtained. (JM)

  10. A Reevaluation of the Attentional Inertia Concept

    NARCIS (Netherlands)

    W.J.M.I. Verbeke (Willem)

    1992-01-01

    textabstractAnderson's (1983) theory about children's attention behavior during television viewing hypothesizes that attention behavior is affected by positive feedback (the inertia hypothesis) and the degree to which a child understands the television program. During an experiment, neither componen

  11. Sleep Inertia and On-Call Readiness

    Science.gov (United States)

    2000-03-01

    effects of polyphasic & M.J. Colligan (Eds.), New York, and ultrashort sleep schedules. In: Why Spectrum, pp. 553-580. we nap, Evolution, Chronobiology...and Naitoh, P., Kelly, T., & Babkoff, H. (1993) Functions of Polyphasic and Ultrashort Sleep inertia, best time not to wake up? Sleep , C. Stampi Editor...UNCLASSIFIED Defense Technical Information Center Compilation Part Notice ADP010467 TITLE: Sleep Inertia and On-Call Readiness DISTRIBUTION: Approved

  12. Osteopathic manipulative treatment for colonic inertia.

    Science.gov (United States)

    Cohen-Lewe, Adam

    2013-03-01

    Surgical treatment options for patients with colonic inertia are costly and do not always relieve the pain associated with the condition. The author describes a case of a 41-year-old woman with colonic inertia who received osteopathic manipulative treatment targeted at the neuromusculoskeletal and gastrointestinal systems. The patient reported temporary improvement in pain and bowel function without pharmacotherapy or surgical intervention. Osteopathic manipulative treatment should be considered in patients with visceral as well as neuromusculoskeletal symptoms.

  13. Welding Curtains

    Science.gov (United States)

    1984-01-01

    Concept of transparent welding curtains made of heavy duty vinyl originated with David F. Wilson, President of Wilson Sales Company. In 1968, Wilson's curtains reduced glare of welding arc and blocked ultraviolet radiation. When later research uncovered blue light hazards, Wilson sought improvement of his products. He contracted Dr. Charles G. Miller and James B. Stephens, both of Jet Propulsion Laboratory (JPL), and they agreed to undertake development of a curtain capable of filtering out harmful irradiance, including ultraviolet and blue light and provide protection over a broad range of welding operation. Working on their own time, the JPL pair spent 3 years developing a patented formula that includes light filtering dyes and small particles of zinc oxide. The result was the Wilson Spectra Curtain.

  14. Tracking inhomogeneity in high-capacity lithium iron phosphate batteries

    Science.gov (United States)

    Paxton, William A.; Zhong, Zhong; Tsakalakos, Thomas

    2015-02-01

    Energy-dispersive x-ray diffraction (EDXRD) is one of the few techniques that can internally probe a sealed battery under operating conditions. In this paper, we use EDXRD with ultrahigh energy synchrotron radiation to track inhomogeneity in a cycled high-capacity lithium iron phosphate cell under in-situ and operando conditions. A sequence of depth-profile x-ray diffraction spectra are collected with 40 μm resolution as the cell is discharged. Additionally, nine different locations of the cell are tracked independently throughout a second discharge process. In each case, a two-peak reference intensity ratio analysis (RIR) was used on the LiFePO4 311 and the FePO4 020 reflections to estimate the relative phase abundance of the lithiated and non-lithiated phases. The data provide a first-time look at the dynamics of electrochemical inhomogeneity in a real-world battery. We observe a strong correlation between inhomogeneity and overpotential in the galvanic response of the cell. Additionally, the data closely follow the behavior that is predicted by the resistive-reactant model originally proposed by Thomas-Alyea. Despite a non-linear response in the independently measured locations, the behavior of the ensemble is strikingly linear. This suggests that effects of inhomogeneity can be elusive and highlights the power of the EDXRD technique.

  15. Space qualification of high capacity grooved heat pipes

    Energy Technology Data Exchange (ETDEWEB)

    Dubois, M.; Mullender, B.; Druart, J. [SABCA, Societe Anomyme Belgel de Construction Aeronautique (Belgium); Supper, W.; Beddows, A. [ESTEC-The (Netherlands)

    1996-12-31

    Based on the thermal requirements of the future telecommunication satellites, the development of a High Capacity Grooved Heat Pipe (HPG), was contracted by ESA to SABCA leading to an aluminium extruded heat pipe (outer diameter of 25 mm) based on a multi re-entrant grooves design. After an intensive acceptance test campaign whose results showed a good confidence in the design and the fulfillment of the required specifications of heat transport and on tilt capability (experimental maximum heat transport capability of 1500 Watt metres for a vapour temperature of 20 deg C), similar heat pipes have been developed with various outer diameters (11 mm, 15 mm and 20 mm) and with various shapes (circular outer shapes, integrated saddles). Several of these heat pipes were tested during two parabolic flight campaigns, by varying the heat loads during the micro-gravity periods. This HGP heat pipe family is now being submitted to a space qualification program according to ESA standards (ESA PSS-49), both in straight and bent configuration. Within this qualification, the heat pipes are submitted to an extended test campaign including environmental (random/sinus vibration, constant acceleration) and thermal tests (thermal performance, thermal cycle, thermal soak, ageing). (authors) 9 refs.

  16. High Capacity data hiding using LSB Steganography and Encryption

    Directory of Open Access Journals (Sweden)

    Shamim Ahmed Laskar

    2013-01-01

    Full Text Available The network provides a method of communication to distribute information to the masses. With the growthof data communication over computer network, the security of information has become a major issue.Steganography and cryptography are two different data hiding techniques. Steganography hides messagesinside some other digital media. Cryptography, on the other hand obscures the content of the message. Wepropose a high capacity data embedding approach by the combination of Steganography andcryptography. In the process a message is first encrypted using transposition cipher method and then theencrypted message is embedded inside an image using LSB insertion method. The combination of these twomethods will enhance the security of the data embedded. This combinational methodology will satisfy therequirements such as capacity, security and robustness for secure data transmission over an open channel.A comparative analysis is made to demonstrate the effectiveness of the proposed method by computingMean square error (MSE and Peak Signal to Noise Ratio (PSNR. We analyzed the data hiding techniqueusing the image performance parameters like Entropy, Mean and Standard Deviation. The stego imagesare tested by transmitting them and the embedded data are successfully extracted by the receiver. The mainobjective in this paper is to provide resistance against visual and statistical attacks as well as highcapacity.

  17. High-Capacity, High-Voltage Composite Oxide Cathode Materials

    Science.gov (United States)

    Hagh, Nader M.

    2015-01-01

    This SBIR project integrates theoretical and experimental work to enable a new generation of high-capacity, high-voltage cathode materials that will lead to high-performance, robust energy storage systems. At low operating temperatures, commercially available electrode materials for lithium-ion (Li-ion) batteries do not meet energy and power requirements for NASA's planned exploration activities. NEI Corporation, in partnership with the University of California, San Diego, has developed layered composite cathode materials that increase power and energy densities at temperatures as low as 0 degC and considerably reduce the overall volume and weight of battery packs. In Phase I of the project, through innovations in the structure and morphology of composite electrode particles, the partners successfully demonstrated an energy density exceeding 1,000 Wh/kg at 4 V at room temperature. In Phase II, the team enhanced the kinetics of Li-ion transport and electronic conductivity at 0 degC. An important feature of the composite cathode is that it has at least two components that are structurally integrated. The layered material is electrochemically inactive; however, upon structural integration with a spinel material, the layered material can be electrochemically activated and deliver a large amount of energy with stable cycling.

  18. High-Capacity Spacesuit Evaporator Absorber Radiator (SEAR)

    Science.gov (United States)

    Izenson, Michael G.; Chen, Weibo; Phillips, Scott; Chepko, Ariane; Bue, Grant; Quinn, Gregory

    2015-01-01

    Future human space exploration missions will require advanced life support technology that can operate across a wide range of applications and environments. Thermal control systems for space suits and spacecraft will need to meet critical requirements for water conservation and multifunctional operation. This paper describes a Space Evaporator Absorber Radiator (SEAR) that has been designed to meet performance requirements for future life support systems. A SEAR system comprises a lithium chloride absorber radiator (LCAR) for heat rejection coupled with a space water membrane evaporator (SWME) for heat acquisition. SEAR systems provide heat pumping to minimize radiator size, thermal storage to accommodate variable environmental conditions, and water absorption to minimize use of expendables. We have built and tested a flight-like, high-capacity LCAR, demonstrated its performance in thermal vacuum tests, and explored the feasibility of an ISS demonstration test of a SEAR system. The new LCAR design provides the same cooling capability as prior LCAR prototypes while enabling over 30% more heat absorbing capacity. Studies show that it should be feasible to demonstrate SEAR operation in flight by coupling with an existing EMU on the space station.

  19. High-capacity quantum Fibonacci coding for key distribution

    Science.gov (United States)

    Simon, David S.; Lawrence, Nate; Trevino, Jacob; Dal Negro, Luca; Sergienko, Alexander V.

    2013-03-01

    Quantum cryptography and quantum key distribution (QKD) have been the most successful applications of quantum information processing, highlighting the unique capability of quantum mechanics, through the no-cloning theorem, to securely share encryption keys between two parties. Here, we present an approach to high-capacity, high-efficiency QKD by exploiting cross-disciplinary ideas from quantum information theory and the theory of light scattering of aperiodic photonic media. We propose a unique type of entangled-photon source, as well as a physical mechanism for efficiently sharing keys. The key-sharing protocol combines entanglement with the mathematical properties of a recursive sequence to allow a realization of the physical conditions necessary for implementation of the no-cloning principle for QKD, while the source produces entangled photons whose orbital angular momenta (OAM) are in a superposition of Fibonacci numbers. The source is used to implement a particular physical realization of the protocol by randomly encoding the Fibonacci sequence onto entangled OAM states, allowing secure generation of long keys from few photons. Unlike in polarization-based protocols, reference frame alignment is unnecessary, while the required experimental setup is simpler than other OAM-based protocols capable of achieving the same capacity and its complexity grows less rapidly with increasing range of OAM used.

  20. ARc Welding (Industrial Processing Series).

    Science.gov (United States)

    ARC WELDING , *BIBLIOGRAPHIES), (*ARC WELDS, BIBLIOGRAPHIES), ALUMINUM ALLOYS, TITANIUM ALLOYS, CHROMIUM ALLOYS, METAL PLATES, SPOT WELDING , STEEL...INERT GAS WELDING , MARAGING STEELS, MICROSTRUCTURE, HEAT RESISTANT ALLOYS, HEAT RESISTANT METALS, WELDABILITY, MECHANICAL PROPERTIES, MOLYBDENUM ALLOYS, NICKEL ALLOYS, RESISTANCE WELDING

  1. Experimental Study of the Moment of Inertia of a Cone--Angular Variation and Inertia Ellipsoid

    Science.gov (United States)

    Pintao, Carlos A. F.; de Souza Filho, Moacir P.; Usida, Wesley F.; Xavier, Jose A.

    2007-01-01

    In this paper, an experimental set-up which differs from the traditional ones is established in order to determine the moment of inertia of a right circular cone. Its angular variation and inertia ellipsoid are determined by means of an experimental study. In addition, a system that allows for the evaluation of the angular acceleration and torque…

  2. Upset Prediction in Friction Welding Using Radial Basis Function Neural Network

    Directory of Open Access Journals (Sweden)

    Wei Liu

    2013-01-01

    Full Text Available This paper addresses the upset prediction problem of friction welded joints. Based on finite element simulations of inertia friction welding (IFW, a radial basis function (RBF neural network was developed initially to predict the final upset for a number of welding parameters. The predicted joint upset by the RBF neural network was compared to validated finite element simulations, producing an error of less than 8.16% which is reasonable. Furthermore, the effects of initial rotational speed and axial pressure on the upset were investigated in relation to energy conversion with the RBF neural network. The developed RBF neural network was also applied to linear friction welding (LFW and continuous drive friction welding (CDFW. The correlation coefficients of RBF prediction for LFW and CDFW were 0.963 and 0.998, respectively, which further suggest that an RBF neural network is an effective method for upset prediction of friction welded joints.

  3. Spacetime Deformation-Induced Inertia Effects

    Directory of Open Access Journals (Sweden)

    Gagik Ter-Kazarian

    2012-01-01

    Full Text Available We construct a toy model of spacetime deformation-induced inertia effects, in which we prescribe to each and every particle individually a new fundamental constituent of hypothetical 2D, so-called master space (MS, subject to certain rules. The MS, embedded in the background 4D-spacetime, is an indispensable companion to the particle of interest, without relation to every other particle. The MS is not measurable directly, but we argue that a deformation (distortion of local internal properties of MS is the origin of inertia effects that can be observed by us. With this perspective in sight, we construct the alternative relativistic theory of inertia. We go beyond the hypothesis of locality with special emphasis on distortion of MS, which allows to improve essentially the standard metric and other relevant geometrical structures referred to a noninertial frame in Minkowski spacetime for an arbitrary velocities and characteristic acceleration lengths. Despite the totally different and independent physical sources of gravitation and inertia, this approach furnishes justification for the introduction of the weak principle of equivalence (WPE, that is, the universality of free fall. Consequently, we relate the inertia effects to the more general post-Riemannian geometry.

  4. Design of high-capacity fiber-optic transport systems

    Science.gov (United States)

    Liao, Zhi Ming

    2001-08-01

    We study the design of fiber-optic transport systems and the behavior of fiber amplifiers/lasers with the aim of achieving higher capacities with larger amplifier spacing. Solitons are natural candidates for transmitting short pulses for high-capacity fiber-optic networks because of its innate ability to use two of fiber's main defects, fiber dispersion and fiber nonlinearity to balance each other. In order for solitons to retain its dynamic nature, amplifiers must be placed periodically to restore powers to compensate for fiber loss. Variational analysis is used to study the long-term stability of a periodical- amplifier system. A new regime of operation is identified which allows the use of a much longer amplifier spacing. If optical fibers are the blood vessels of an optical communication system, then the optical amplifier based on erbium-doped fiber is the heart. Optical communication systems can avoid the use of costly electrical regenerators to maintain system performance by being able to optically amplify the weakened signals. The length of amplifier spacing is largely determined by the gain excursion experienced by the solitons. We propose, model, and demonstrate a distributed erbium-doped fiber amplifier which can drastically reduce the amount of gain excursion experienced by the solitons, therefore allowing a much longer amplifier spacing and superior stability. Dispersion management techniques have become extremely valuable tools in the design of fiber-optic communication systems. We have studied in depth the advantage of different arnplification schemes (lumped and distributed) for various dispersion compensation techniques. We measure the system performance through the Q factor to evaluate the added advantage of effective noise figure and smaller gain excursion. An erbium-doped fiber laser has been constructed and characterized in an effort to develop a test bed to study transmission systems. The presence of mode-partition noise in an erbium

  5. Connectivity and the Origin of Inertia

    CERN Document Server

    Nickisch, L J; Mollere, Jules

    2002-01-01

    Newton's Second Law defines inertial mass as the ratio of the applied force on an object to the responding acceleration of the object (viz., F=ma). Objects that exhibit finite accelerations under finite forces are described as being "massive'' and this mass has usually been considered to be an innate property of the particles composing the object. However mass itself is never directly measured. It is inertia, the reaction of the object to impressed forces, that is measured. We show that the effects of inertia are equally well explained as a consequence of the vacuum fields acting on massless particles travelling in geodesic motion. In this approach, the vacuum fields in the particle's history define the curvature of the particle's spacetime. The metric describing this curvature implies a transformation to Minkowski spacetime, which we call the Connective transformation. Application of the Connective transformation produces the usual effects of inertia when observed in Minkowski spacetime, including hyperbolic...

  6. Scan Quantum Mechanics: Quantum Inertia Stops Superposition

    CERN Document Server

    Gato-Rivera, Beatriz

    2015-01-01

    A novel interpretation of the quantum mechanical superposition is put forward. Quantum systems scan all possible available states and switch randomly and very rapidly among them. The longer they remain in a given state, the larger the probability of the system to be found in that state during a measurement. A crucial property that we postulate is quantum inertia, that increases whenever a constituent is added, or the system is perturbed with all kinds of interactions. Once the quantum inertia $I_q$ reaches a critical value $I_{cr}$ for an observable, the switching among the different eigenvalues of that observable stops and the corresponding superposition comes to an end. Consequently, increasing the mass, temperature, gravitational force, etc. of a quantum system increases its quantum inertia until the superposition of states disappears for all the observables and the system transmutes into a classical one. The process could be reversible decreasing the size, temperature, gravitational force, etc. leading to...

  7. Pulsar braking: Time dependent moment of inertia?

    Science.gov (United States)

    Urbanec, Martin

    2017-08-01

    Pulsars rotate with extremely stable rotational frequency enabling one to measure its first and second time derivatives. These observed values can be combined to the so-called braking index. However observed values of braking index differ from the theoretical value of 3 corresponding to braking by magnetic dipole radiation being the dominant theoretical model. Such a difference can be explained by contribution of other mechanism like pulsar wind or quadrupole radiation, or by time dependency of magnetic field or moment of inertia. In this presentation we focus on influence of time dependent moment of inertia on the braking index. We will also discuss possible physical models for time-dependence of moment of inertia.

  8. Filament stretching rheometer: inertia compensation revisited

    DEFF Research Database (Denmark)

    Szabo, Peter; McKinley, Gareth H.

    2003-01-01

    The necessary inertia compensation used in the force balance for the filament stretching rheometer is derived for an arbitrary frame of reference. This enables the force balance to be used to extract correctly the extensional viscosity from measurements of the tensile force at either end of the e......The necessary inertia compensation used in the force balance for the filament stretching rheometer is derived for an arbitrary frame of reference. This enables the force balance to be used to extract correctly the extensional viscosity from measurements of the tensile force at either end...

  9. Welding processes handbook

    CERN Document Server

    Weman, Klas

    2011-01-01

    Offers an introduction to the range of available welding technologies. This title includes chapters on individual techniques that cover principles, equipment, consumables and key quality issues. It includes material on such topics as the basics of electricity in welding, arc physics, and distortion, and the weldability of particular metals.$bThe first edition of Welding processes handbook established itself as a standard introduction and guide to the main welding technologies and their applications. This new edition has been substantially revised and extended to reflect the latest developments. After an initial introduction, the book first reviews gas welding before discussing the fundamentals of arc welding, including arc physics and power sources. It then discusses the range of arc welding techniques including TIG, plasma, MIG/MAG, MMA and submerged arc welding. Further chapters cover a range of other important welding technologies such as resistance and laser welding, as well as the use of welding techniqu...

  10. Friction Stir Welding

    Science.gov (United States)

    Nunes, Arthur C., Jr.

    2008-01-01

    Friction stir welding (FSW) is a solid state welding process invented in 1991 at The Welding Institute in the United Kingdom. A weld is made in the FSW process by translating a rotating pin along a weld seam so as to stir the sides of the seam together. FSW avoids deleterious effects inherent in melting and promises to be an important welding process for any industries where welds of optimal quality are demanded. This article provides an introduction to the FSW process. The chief concern is the physical effect of the tool on the weld metal: how weld seam bonding takes place, what kind of weld structure is generated, potential problems, possible defects for example, and implications for process parameters and tool design. Weld properties are determined by structure, and the structure of friction stir welds is determined by the weld metal flow field in the vicinity of the weld tool. Metal flow in the vicinity of the weld tool is explained through a simple kinematic flow model that decomposes the flow field into three basic component flows: a uniform translation, a rotating solid cylinder, and a ring vortex encircling the tool. The flow components, superposed to construct the flow model, can be related to particular aspects of weld process parameters and tool design; they provide a bridge to an understanding of a complex-at-first-glance weld structure. Torques and forces are also discussed. Some simple mathematical models of structural aspects, torques, and forces are included.

  11. Magnitude and Time Course of Sleep Inertia

    Science.gov (United States)

    2008-10-10

    1-hour nap. Work & Stress. 1995;9(4):528-39. 20. Naitoh P, Kelly T, Babkoff H. Sleep Inertia: best time not to wake up? Chronobiology ...Ostberg O. A self-assessment questionnaire to determine morningness-eveningness in human circadian rhythms. International Journal Of Chronobiology . 1976;4:97-110.

  12. Topology optimization of inertia driven dosing units

    DEFF Research Database (Denmark)

    Andreasen, Casper Schousboe

    2016-01-01

    This paper presents a methodology for optimizing inertia driven dosing units, sometimes referred to as eductors, for use in small scale flow applications. The unit is assumed to operate at low to moderate Reynolds numbers and under steady state conditions. By applying topology optimization...

  13. Nonlinear Inertia Classification Model and Application

    Directory of Open Access Journals (Sweden)

    Mei Wang

    2014-01-01

    Full Text Available Classification model of support vector machine (SVM overcomes the problem of a big number of samples. But the kernel parameter and the punishment factor have great influence on the quality of SVM model. Particle swarm optimization (PSO is an evolutionary search algorithm based on the swarm intelligence, which is suitable for parameter optimization. Accordingly, a nonlinear inertia convergence classification model (NICCM is proposed after the nonlinear inertia convergence (NICPSO is developed in this paper. The velocity of NICPSO is firstly defined as the weighted velocity of the inertia PSO, and the inertia factor is selected to be a nonlinear function. NICPSO is used to optimize the kernel parameter and a punishment factor of SVM. Then, NICCM classifier is trained by using the optical punishment factor and the optical kernel parameter that comes from the optimal particle. Finally, NICCM is applied to the classification of the normal state and fault states of online power cable. It is experimentally proved that the iteration number for the proposed NICPSO to reach the optimal position decreases from 15 to 5 compared with PSO; the training duration is decreased by 0.0052 s and the recognition precision is increased by 4.12% compared with SVM.

  14. Moment of inertia, backbending, and molecular bifurcation.

    Science.gov (United States)

    Tyng, Vivian; Kellman, Michael E

    2007-07-28

    We predict an anomaly in highly excited bending spectra of acetylene with high vibrational angular momentum. We interpret this in terms of a vibrational shape effect with moment of inertia backbending, induced by a sequence of bifurcations with a transition from "local" to "orthogonal" modes.

  15. Distortion Control during Welding

    NARCIS (Netherlands)

    Akbari Pazooki, A.M.

    2014-01-01

    The local material expansion and contraction involved in welding result in permanent deformations or instability i.e., welding distortion. Considerable efforts have been made in controlling welding distortion prior to, during or after welding. Thermal Tensioning (TT) describes a group of in-situ met

  16. Introduction to Welding.

    Science.gov (United States)

    Fortney, Clarence; Gregory, Mike

    This curriculum guide provides six units of instruction on basic welding. Addressed in the individual units of instruction are the following topics: employment opportunities for welders, welding safety and first aid, welding tools and equipment, basic metals and metallurgy, basic math and measuring, and procedures for applying for a welding job.…

  17. Laser welding in space

    Science.gov (United States)

    Kaukler, W. F.; Workman, G. L.

    1991-01-01

    Autogenous welds in 304 stainless steel were performed by Nd-YAG laser heating in a simulated space environment. Simulation consists of welding on the NASA KC-135 aircraft to produce the microgravity and by containing the specimen in a vacuum chamber. Experimental results show that the microgravity welds are stronger, harder in the fusion zone, have deeper penetration and have a rougher surface rippling of the weld pool than one-g welds. To perform laser welding in space, a solar-pumped laser concept that significantly increases the laser conversion efficiency and makes welding viable despite the limited power availability of spacecraft is proposed.

  18. Advanced Welding Applications

    Science.gov (United States)

    Ding, Robert J.

    2010-01-01

    Some of the applications of advanced welding techniques are shown in this poster presentation. Included are brief explanations of the use on the Ares I and Ares V launch vehicle and on the Space Shuttle Launch vehicle. Also included are microstructural views from four advanced welding techniques: Variable Polarity Plasma Arc (VPPA) weld (fusion), self-reacting friction stir welding (SR-FSW), conventional FSW, and Tube Socket Weld (TSW) on aluminum.

  19. A Consideration on Inertia-Ratio and Vibration Control of Two-Inertia System

    Science.gov (United States)

    Takesue, Naoyuki; Furusho, Junji; Iwakoshi, Kunio

    Most Industrial robots are driven through reduction gears such as harmonic drives and RV gears. Since the exibility of the drive system, the vibratory behavior is caused duringthe operation. When the exibility is considered, the drive system of the robot joint can be modeled as a resonant mechanical system called two-inertia system. Two-inertia systems are the vibratory systems that have poles on/near the imaginary axis. Acceleration feedback and torque feedback are known as the vibration control methods of two-inertia systems. In this paper, we consider the two-inertia system with the feedbacks of motor-acceleration, load-acceleration and torsion-torque. It is shown that each feedback works to control the inertia-ratio of two-inertia system. Then, the control performances are compared. Torsion vibration in robot joint, which occurs owingto the accuracy of components and assembly error of gears at a certain speed of rotation, becomes a problem. In order to suppress the torsion vibration, each feedback is applied to the robot arm. As a result, the torsion vibrations are suppressed e ectively.

  20. The latent effect of inertia in the modal choice

    DEFF Research Database (Denmark)

    Cherchi, Elisabetta; Meloni, Italo; Ortúzar, Juan de Dios

    2014-01-01

    The existence of habit (leading to inertia) in the choice process has been approached in the literature in a number of ways. In transport, inertia has been studied mainly using “long panel” data, or mixed revealed and stated preference data. In these studies inertia links the choice made in two o...

  1. Welded solar cell interconnection

    Science.gov (United States)

    Stofel, E. J.; Browne, E. R.; Meese, R. A.; Vendura, G. J.

    1982-01-01

    The efficiency of the welding of solar-cell interconnects is compared with the efficiency of soldering such interconnects, and the cases in which welding may be superior are examined. Emphasis is placed on ultrasonic welding; attention is given to the solar-cell welding machine, the application of the welding process to different solar-cell configurations, producibility, and long-life performance of welded interconnects. Much of the present work has been directed toward providing increased confidence in the reliability of welding using conditions approximating those that would occur with large-scale array production. It is concluded that there is as yet insufficient data to determine which of three methods (soldering, parallel gap welding, and ultrasonic welding) provides the longest-duration solar panel life.

  2. Inertia in Friedmann Universes with variable and

    Science.gov (United States)

    Sultana, J.; Kazanas, D.

    2015-09-01

    In light of the recent interest in dynamical dark energy models based on a cosmology with varying gravitational and cosmological parameters and , we present here a model of inertia in a type of Friedmann universe with ; being the dimensionless scale factor, that was recently studied by Singh et al. (Astrophys. Space Sci. 345:213, 2013). The proposed Machian model of inertia utilizes the curved space generalization of Sciama's law of inertial induction, which is based on the analogy between the retarded far fields of electrodynamics and those of gravitation, and expresses the total inertial force on an accelerating mass in terms of contributions from all matter in the observable Universe. We show that for a varying Friedmann model with , inertial induction alone can account for the total inertial force on the accelerating mass. We then compare this cosmological model with current observational constraints for the variation of.

  3. Realization of Thermal Inertia in Frequency Domain

    Directory of Open Access Journals (Sweden)

    Boe-Shong Hong

    2014-02-01

    Full Text Available To realize the lagging behavior in heat conduction observed in these two decades, this paper firstly theoretically excludes the possibility that the underlying thermal inertia is a result of the time delay in heat diffusion. Instead, we verify in experiments the electro-thermal analogy, wherein the thermal inertial is parameterized by thermal inductance that formulates hyperbolic heat-conduction. The thermal hyperbolicity exhibits a special frequency response in Bode plot, wherein the amplitude ratios is kept flat after crossing some certain frequency, as opposed to Fourier heat-conduction. We apply this specialty to design an instrument that reliably identifies thermal inductances of some materials in frequency domain. The instrument is embedded with a DSP-based frequency synthesizer capable of modulating frequencies in utmost high-resolution. Thermal inertia implies a new possibility for energy storage in analogy to inductive energy storage in electricity or mechanics.

  4. Finite Element Analysis of Inertia Dynamometer

    Directory of Open Access Journals (Sweden)

    R. A. Gujar

    2013-12-01

    Full Text Available The Dynamometer is a LOAD device. It applies a load to an engine so we can test the performance of the engine under a variety of circumstances. System operates where load (dyno torque equals that of the Engine. By varying the engine throttle and load we can test any point under the engines max torque curve. We design and modify engines for improved fuel economy and emissions We need DATA to quantify the improvements in Fuel savings and Emissions reductions. This data will be used to help us “tune in” our design. The Dynamometer is operated at 1000 rpm to generate the necessary inertia. For different kind of conditions, there is need of having variable inertia. So the dynamometer is constructed with removable flywheel.

  5. Magnetic charges, inertia, and arrow of time

    Science.gov (United States)

    Magnon, Anne M. R.

    1990-02-01

    The prerelativistic concept of inertial mass (as opposed to gravitational mass) is reconsidered in view of a possible relationship between inertia and magnetic (mass) monopoles. Assuming that such “fictitious” (topological) charges could have developed in the chaotic early cosmology, a physical principle is suggested, based on dissipation of topological charges and decoupling of interactions, which could have governed the onset of inertia and of the arrow of time, and controlled the critical balance between mass density and expansion rate in the FRW universe. In view of the recent accomplishments in the detection of Dirac monopoles, a generalization of the Eötvos experiment is proposed which could shed light on the grand unification regime. A comment is given on the issue of relating the psychological and the cosmological arrows of time.

  6. Two-fluid turbulence including electron inertia

    Energy Technology Data Exchange (ETDEWEB)

    Andrés, Nahuel, E-mail: nandres@iafe.uba.ar; Gómez, Daniel [Instituto de Astronomía y Física del Espacio, CC. 67, suc. 28, 1428 Buenos Aires (Argentina); Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón I, 1428 Buenos Aires (Argentina); Gonzalez, Carlos; Martin, Luis; Dmitruk, Pablo [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET, 1428 Buenos Aires (Argentina)

    2014-12-15

    We present a full two-fluid magnetohydrodynamic (MHD) description for a completely ionized hydrogen plasma, retaining the effects of the Hall current, electron pressure, and electron inertia. According to this description, each plasma species introduces a new spatial scale: the ion inertial length λ{sub i} and the electron inertial length λ{sub e}, which are not present in the traditional MHD description. In the present paper, we seek for possible changes in the energy power spectrum in fully developed turbulent regimes, using numerical simulations of the two-fluid equations in two-and-a-half dimensions. We have been able to reproduce different scaling laws in different spectral ranges, as it has been observed in the solar wind for the magnetic energy spectrum. At the smallest wavenumbers where plain MHD is valid, we obtain an inertial range following a Kolmogorov k{sup −5∕3} law. For intermediate wavenumbers such that λ{sub i}{sup −1}≪k≪λ{sub e}{sup −1}, the spectrum is modified to a k{sup −7∕3} power-law, as has also been obtained for Hall-MHD neglecting electron inertia terms. When electron inertia is retained, a new spectral region given by k>λ{sub e}{sup −1} arises. The power spectrum for magnetic energy in this region is given by a k{sup −11∕3} power law. Finally, when the terms of electron inertia are retained, we study the self-consistent electric field. Our results are discussed and compared with those obtained in the solar wind observations and previous simulations.

  7. Spin-Mechanical Inertia in Antiferromagnet

    OpenAIRE

    2016-01-01

    The conservation of angular momentum has served as a guiding principle in the coupled dynamics of quantum spins and mechanical rotations. However, in an antiferromagnet with vanishing magnetization, new fundamental rules are required to properly describe spin-mechanical phenomena. Here we demonstrate that the Neel order dynamics affects the mechanical motion of a rigid body by modifying its inertia tensor in the presence of strong magnetocrystalline anisotropy. This effect depends on temperat...

  8. Quantum inertia stops superposition: Scan Quantum Mechanics

    Science.gov (United States)

    Gato-Rivera, Beatriz

    2017-08-01

    Scan Quantum Mechanics is a novel interpretation of some aspects of quantum mechanics in which the superposition of states is only an approximate effective concept. Quantum systems scan all possible states in the superposition and switch randomly and very rapidly among them. A crucial property that we postulate is quantum inertia, that increases whenever a constituent is added, or the system is perturbed with all kinds of interactions. Once the quantum inertia Iq reaches a critical value Icr for an observable, the switching among its different eigenvalues stops and the corresponding superposition comes to an end, leaving behind a system with a well defined value of that observable. Consequently, increasing the mass, temperature, gravitational strength, etc. of a quantum system increases its quantum inertia until the superposition of states disappears for all the observables and the system transmutes into a classical one. Moreover, the process could be reversible. Entanglement can only occur between quantum systems because an exact synchronization between the switchings of the systems involved must be established in the first place and classical systems do not have any switchings to start with. Future experiments might determine the critical inertia Icr corresponding to different observables, which translates into a critical mass Mcr for fixed environmental conditions as well as critical temperatures, critical electric and magnetic fields, etc. In addition, this proposal implies a new radiation mechanism from astrophysical objects with strong gravitational fields, giving rise to non-thermal synchrotron emission, that could contribute to neutron star formation. Superconductivity, superfluidity, Bose-Einstein condensates, and any other physical phenomena at very low temperatures must be reanalyzed in the light of this interpretation, as well as mesoscopic systems in general.

  9. Exploring inertia in a typical state organisation

    Directory of Open Access Journals (Sweden)

    G. J. Louw

    2004-10-01

    Full Text Available Those organisations which do not change according to environmental pressures, suffer from organisational inertia. The purpose of this study is to explore the manifestation of organisational inertia in the target organisation. The target population for this study was a group of trainees, representing the geographic and demographic levels of a particular state department. In South Africa, surveys of this nature were only executed in the corporate sector. The results indicate that organisational inertia is a phenomenon that affects both corporate and governmental organisations. Opsomming Organisasies wat nie ooreenkomstig omgewingsdruk verander nie, ly aan organisasietraagheid. Die doel van die studie is om organisasietraagheid te konseptualiseer en die manifestasie daarvan in die teikenorganisasie te ondersoek. Die teikenpopulasie bestaan uit ’n groep kursusgangers wat die demografiese en geografiese samestelling van ‘n tipiese staatsdepartement verteenwoordig. In Suid -Afrika is navorsing van hierdie aard nog net in die korporatiewe sektor uitgevoer. Die resultate toon aan dat organisasietraagheid ‘n faktor is wat beide die korporatiewe omgewing en staatsorganisasies beïnvloed.

  10. Laparoscopic subtotal colectomy for colonic inertia.

    Science.gov (United States)

    Sample, Cliff; Gupta, Rohit; Bamehriz, Fahad; Anvari, Mehran

    2005-01-01

    Colonic inertia is an uncommon condition, usually occurring in women in the third decade of life. Severity of symptoms may lead some patients to a surgical consultation. This is a retrospective review of 14 patients who underwent laparoscopic subtotal colectomy for colonic inertia, performed by a single surgeon from August 1993 to November 2002. The mean age of the patients was 38.5 years (range 26-50 years); 93% of the patients were women. The common presenting symptoms included abdominal pain (93%), bloating (100%), constipation (100%), and nausea (57%). Median duration of symptoms before surgery was 4.5 years (range 1-30 years). Subtotal colectomy was completed laparoscopically in 13 patients. There was one conversion (7%) because of adhesions. Eleven patients (78.6%) had undergone previous abdominal surgery. The mean operating room time was 153 minutes (range 113-210 minutes). The median time to full bowel action was 2 days. One patient developed postoperative small bowel obstruction that required open exploration. Complete follow-up was available for 11 patients at a median follow-up of 18 months (range 2-96 months). Ninety-one percent of the patients reported excellent satisfaction with surgery, and their bowel movement frequency changed from 1.2 (+/-0.2) per week preoperatives to 17.2 (+/-2.9) per week postoperatively (P relief in patients with colonic inertia who do not respond to medical measures.

  11. Handbook of Plastic Welding

    DEFF Research Database (Denmark)

    Islam, Aminul

    The purpose of this document is to summarize the information about the laser welding of plastic. Laser welding is a matured process nevertheless laser welding of micro dimensional plastic parts is still a big challenge. This report collects the latest information about the laser welding of plasti...... as a knowledge handbook for laser welding of plastic components. This document should provide the information for all aspects of plastic laser welding and help the design engineers to take all critical issues into consideration from the very beginning of the design phase....

  12. Frequency Assignment for Joint Aerial Layer Network High-Capacity Backbone

    Science.gov (United States)

    2017-08-11

    ARL-TR-8093•AUG 2017 US Army Research Laboratory Frequency Assignment for Joint Aerial Layer Network High-Capacity Backbone by Peng Wang and Brian...2017 US Army Research Laboratory Frequency Assignment for Joint Aerial Layer Network High-Capacity Backbone by Peng Wang and Brian Henz Computational...Rev. 8/98)    Prescribed by ANSI Std. Z39.18 August 2017 Technical Report Frequency Assignment for Joint Aerial Layer Network High-Capacity Backbone

  13. Mesoporous Silicon-Based Anodes for High Capacity, High Performance Li-ion Batteries Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A new high capacity anode composite based on mesoporous silicon is proposed. By virtue of a structure that resembles a pseudo one-dimensional phase, the active...

  14. Mesoporous Silicon-Based Anodes for High Capacity, High Performance Li-ion Batteries Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A new high capacity anode composite based on mesoporous silicon is proposed. By virtue of a structure that resembles a pseudo one-dimensional phase, the active anode...

  15. Multi-core Fibers in Submarine Networks for High-Capacity Undersea Transmission Systems

    DEFF Research Database (Denmark)

    Nooruzzaman, Md; Morioka, Toshio

    2017-01-01

    Application of multi-core fibers in undersea networks for high-capacity submarine transmission systems is studied. It is demonstrated how different architectures of submerged branching unit affect network component counts in long-haul undersea transmission systems......Application of multi-core fibers in undersea networks for high-capacity submarine transmission systems is studied. It is demonstrated how different architectures of submerged branching unit affect network component counts in long-haul undersea transmission systems...

  16. Comparing Laser Welding Technologies with Friction Stir Welding for Production of Aluminum Tailor-Welded Blanks

    Energy Technology Data Exchange (ETDEWEB)

    Hovanski, Yuri; Carsley, John; Carlson, Blair; Hartfield-Wunsch, Susan; Pilli, Siva Prasad

    2014-01-15

    A comparison of welding techniques was performed to determine the most effective method for producing aluminum tailor-welded blanks for high volume automotive applications. Aluminum sheet was joined with an emphasis on post weld formability, surface quality and weld speed. Comparative results from several laser based welding techniques along with friction stir welding are presented. The results of this study demonstrate a quantitative comparison of weld methodologies in preparing tailor-welded aluminum stampings for high volume production in the automotive industry. Evaluation of nearly a dozen welding variations ultimately led to down selecting a single process based on post-weld quality and performance.

  17. Coil Welding Aid

    Science.gov (United States)

    Wiesenbach, W. T.; Clark, M. C.

    1983-01-01

    Positioner holds coil inside cylinder during tack welding. Welding aid spaces turns of coil inside cylinder and applies contact pressure while coil is tack-welded to cylinder. Device facilitates fabrication of heat exchangers and other structures by eliminating hand-positioning and clamping of individual coil turns.

  18. Variable polarity arc welding

    Science.gov (United States)

    Bayless, E. O., Jr.

    1991-01-01

    Technological advances generate within themselves dissatisfactions that lead to further advances in a process. A series of advances in welding technology which culminated in the Variable Polarity Plasma Arc (VPPA) Welding Process and an advance instituted to overcome the latest dissatisfactions with the process: automated VPPA welding are described briefly.

  19. Welding Course Curriculum.

    Science.gov (United States)

    Genits, Joseph C.

    This guide is intended for use in helping students gain a fundamental background on the major aspects of the welding trade. The course emphasis is on mastery of the manipulative skills necessary to develop successful welding techniques and on acquisition of an understanding of the specialized tools and equipment used in welding. The first part…

  20. Instructional Guidelines. Welding.

    Science.gov (United States)

    Fordyce, H. L.; Doshier, Dale

    Using the standards of the American Welding Society and the American Society of Mechanical Engineers, this welding instructional guidelines manual presents a course of study in accordance with the current practices in industry. Intended for use in welding programs now practiced within the Federal Prison System, the phases of the program are…

  1. Brownian transport in corrugated channels with inertia

    CERN Document Server

    Ghosh, P K; Marchesoni, F; Nori, F; Schmid, G; 10.1103/PhysRevE.86.021112

    2012-01-01

    The transport of suspended Brownian particles dc-driven along corrugated narrow channels is numerically investigated in the regime of finite damping. We show that inertial corrections cannot be neglected as long as the width of the channel bottlenecks is smaller than an appropriate particle diffusion length, which depends on the the channel corrugation and the drive intensity. Being such a diffusion length inversely proportional to the damping constant, transport through sufficiently narrow obstructions turns out to be always sensitive to the viscosity of the suspension fluid. The inertia corrections to the transport quantifiers, mobility and diffusivity, markedly differ for smoothly and sharply corrugated channels.

  2. Effect of welding parameters of Gas Metal Arc welding on weld bead geometry: A Review

    Directory of Open Access Journals (Sweden)

    Pushp Kumar Baghel

    2012-07-01

    Full Text Available Weld quality comprises bead geometry and its microstructure, which influence the mechanical properties of the weld. This brief review illustrates the effect of pulse parameters on weld quality. The responsefactors, namely bead penetration, weld width, reinforcement height, weld penetration shape factor and weld reinforcement form factor as affected by arc voltage, wire feed rate, welding speed, gas flow rate and nozzle-toplate distance has also been analysed

  3. Synchrophasor Measurement-Based Wind Plant Inertia Estimation: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y.; Bank, J.; Wan, Y. H.; Muljadi, E.; Corbus, D.

    2013-05-01

    The total inertia stored in all rotating masses that are connected to power systems, such as synchronous generations and induction motors, is an essential force that keeps the system stable after disturbances. To ensure bulk power system stability, there is a need to estimate the equivalent inertia available from a renewable generation plant. An equivalent inertia constant analogous to that of conventional rotating machines can be used to provide a readily understandable metric. This paper explores a method that utilizes synchrophasor measurements to estimate the equivalent inertia that a wind plant provides to the system.

  4. Optically controlled welding system

    Science.gov (United States)

    Gordon, Stephen S. (Inventor)

    1989-01-01

    An optically controlled welding system (10) wherein a welding torch (12) having through-the-torch viewing capabilities is provided with an optical beam splitter (56) to create a transmitted view and a reflective view of a welding operation. These views are converted to digital signals which are then processed and utilized by a computerized robotic welder (15) to make the welding torch responsive thereto. Other features includes an actively cooled electrode holder (26) which minimizes a blocked portion of the view by virtue of being constructed of a single spoke or arm (28) and a weld pool contour detector (14) comprising a laser beam directed onto the weld pool with the position of specular radiation reflected therefrom being characteristic of a penetrated or unpenetrated condition of the weld pool.

  5. Welding arc plasma physics

    Science.gov (United States)

    Cain, Bruce L.

    1990-01-01

    The problems of weld quality control and weld process dependability continue to be relevant issues in modern metal welding technology. These become especially important for NASA missions which may require the assembly or repair of larger orbiting platforms using automatic welding techniques. To extend present welding technologies for such applications, NASA/MSFC's Materials and Processes Lab is developing physical models of the arc welding process with the goal of providing both a basis for improved design of weld control systems, and a better understanding of how arc welding variables influence final weld properties. The physics of the plasma arc discharge is reasonably well established in terms of transport processes occurring in the arc column itself, although recourse to sophisticated numerical treatments is normally required to obtain quantitative results. Unfortunately the rigor of these numerical computations often obscures the physics of the underlying model due to its inherent complexity. In contrast, this work has focused on a relatively simple physical model of the arc discharge to describe the gross features observed in welding arcs. Emphasis was placed of deriving analytic expressions for the voltage along the arc axis as a function of known or measurable arc parameters. The model retains the essential physics for a straight polarity, diffusion dominated free burning arc in argon, with major simplifications of collisionless sheaths and simple energy balances at the electrodes.

  6. VPPA weld model evaluation

    Science.gov (United States)

    McCutcheon, Kimble D.; Gordon, Stephen S.; Thompson, Paul A.

    1992-07-01

    NASA uses the Variable Polarity Plasma Arc Welding (VPPAW) process extensively for fabrication of Space Shuttle External Tanks. This welding process has been in use at NASA since the late 1970's but the physics of the process have never been satisfactorily modeled and understood. In an attempt to advance the level of understanding of VPPAW, Dr. Arthur C. Nunes, Jr., (NASA) has developed a mathematical model of the process. The work described in this report evaluated and used two versions (level-0 and level-1) of Dr. Nunes' model, and a model derived by the University of Alabama at Huntsville (UAH) from Dr. Nunes' level-1 model. Two series of VPPAW experiments were done, using over 400 different combinations of welding parameters. Observations were made of VPPAW process behavior as a function of specific welding parameter changes. Data from these weld experiments was used to evaluate and suggest improvements to Dr. Nunes' model. Experimental data and correlations with the model were used to develop a multi-variable control algorithm for use with a future VPPAW controller. This algorithm is designed to control weld widths (both on the crown and root of the weld) based upon the weld parameters, base metal properties, and real-time observation of the crown width. The algorithm exhibited accuracy comparable to that of the weld width measurements for both aluminum and mild steel welds.

  7. High-capacity electrode materials for electrochemical energy storage: Role of nanoscale effects

    Indian Academy of Sciences (India)

    Jagjit Nanda; Surendra K Martha; Ramki Kalyanaraman

    2015-06-01

    This review summarizes the current state-of-the art electrode materials used for high-capacity lithium-ion-based batteries and their significant role towards revolutionizing the electrochemical energy storage landscape in the area of consumer electronics, transportation and grid storage application. We discuss the role of nanoscale effects on the electrochemical performance of high-capacity battery electrode materials. Decrease in the particle size of the primary electrode materials from micron to nanometre size improves the ionic and electronic diffusion rates significantly. Nanometre-thick solid electrolyte (such as lithium phosphorous oxynitride) and oxides (such as Al2O3, ZnO, TiO2 etc.) material coatings also improve the interfacial stability and rate capability of a number of battery chemistries. We elucidate these effects in terms of different high-capacity battery chemistries based on intercalation and conversion mechanism.

  8. Inertia as Emerging of a Hamiltonian Constraint System

    CERN Document Server

    Darabi, F

    1998-01-01

    The issue of inertia as opposition to acceleration of a massive point particle in Minkowski space-time is investigated in the context of a Hamiltonian constraint system. It is shown that the inertia as a locally-originating force in Minkowski space-time may emerge due to a global constraint.

  9. Coupling diffusion and maximum entropy models to estimate thermal inertia

    Science.gov (United States)

    Thermal inertia is a physical property of soil at the land surface related to water content. We have developed a method for estimating soil thermal inertia using two daily measurements of surface temperature, to capture the diurnal range, and diurnal time series of net radiation and specific humidi...

  10. Moments of Inertia of Disks and Spheres without Integration

    Science.gov (United States)

    Hong, Seok-Cheol; Hong, Seok-In

    2013-01-01

    Calculation of moments of inertia is often challenging for introductory-level physics students due to the use of integration, especially in non-Cartesian coordinates. Methods that do not employ calculus have been described for finding the rotational inertia of thin rods and other simple bodies. In this paper we use the parallel axis theorem and…

  11. The moments of inertia of Mars

    Science.gov (United States)

    Bills, Bruce G.

    1989-01-01

    The mean moment of inertia of Mars is, at present, very poorly constrained. The generally accepted value of 0.365 M(R-squared) is obtained by assuming that the observed second degree gravity field can be decomposed into a hydrostatic oblate spheroid and a nonhydrostatic prolate spheroid with an equatorial axis of symmetry. An alternative decomposition is advocated in the present analysis. If the nonhydrostatic component is a maximally triaxial ellipsoid (intermediate moment exactly midway between greatest and least), the hydrostatic component is consistent with a mean moment of 0.345 M(R-squared). The plausibility of this decomposition is supported by statistical arguments and comparison with the earth, moon and Venus.

  12. The Problem of Inertia in Friedmann Universes

    CERN Document Server

    Sultana, Joseph

    2011-01-01

    In this paper we study the origin of inertia in a curved spacetime, particularly the spatially flat, open and closed Friedmann universes. This is done using Sciama's law of inertial induction, which is based on Mach's principle, and expresses the analogy between the retarded far fields of electrodynamics and those of gravitation. After obtaining covariant expressions for electromagnetic fields due to an accelerating point charge in Friedmann models, we adopt Sciama's law to obtain the inertial force on an accelerating mass $m$ by integrating over the contributions from all the matter in the universe. The resulting inertial force has the form $F = -kma$, where $k < 1 $ depends on the choice of the cosmological parameters such as $\\Omega_{M}$, $\\Omega_{\\Lambda}$, and $\\Omega_{R}$ and is also red-shift dependent.

  13. Using NASTRAN to model missile inertia loads

    Science.gov (United States)

    Marvin, R.; Porter, C.

    1985-01-01

    An important use of NASTRAN is in the area of structural loads analysis on weapon systems carried aboard aircraft. The program is used to predict bending moments and shears in missile bodies, when subjected to aircraft induced accelerations. The missile, launcher and aircraft wing are idealized, using rod and beam type elements for solution economy. Using the inertia relief capability of NASTRAN, the model is subjected to various acceleration combinations. It is found to be difficult to model the launcher sway braces and hooks which transmit compression only or tension only type forces respectively. A simple, iterative process was developed to overcome this modeling difficulty. A proposed code modification would help model compression or tension only contact type problems.

  14. Overcoming therapeutic inertia in patients with hypertension.

    Science.gov (United States)

    Nesbitt, Shawna D

    2010-01-01

    Uncontrolled blood pressure (BP) remains a leading contributor to cardiovascular disease and mortality worldwide. Although current practice guidelines recommend treating patients with hypertension to defined BP goals, the approach is not widely implemented, and BP control in clinical practice is much worse than that attained in clinical trials. Recent and ongoing clinical trials are utilizing more aggressive approaches with combination therapy as initial treatment. This article discusses the problem of therapeutic or clinical inertia when attempting to control hypertension and highlights differences in BP control rates between clinical trials and real-world practice. Additionally, the rationale for an ongoing treat-to-goal study using a fixed-dose combination of amlodipine/olmesartan medoxomil in patients with hypertension not controlled on monotherapy is provided.

  15. Gravitational potential, inertia and Earth rotation

    CERN Document Server

    Bourda, G

    2007-01-01

    Several satellite missions, devoted to the study of the Earth gravity field, have been launched (like CHAMP, recently). This year, GRACE (Gravity Recovery and Climate Experiment) will allow us to obtain a more precise geoid. But the most important is that they will supply the temporal variations of the geopotential coefficients (called Stokes coefficients). In the poster we show how the Earth gravitational potential is linked to the Earth rotation parameters. Indeed, through the Earth inertia coefficients, we can connect the variation of LOD and Polar Motion with the temporal variations of the Stokes coefficients. We also consider the nutations, that are related to the gravitational geopotential coefficients. We discuss the possibility of using the Stokes coefficients in order to improve our knowledge of the Earth rotation.

  16. Effects of moment of inertia on simple reaction time.

    Science.gov (United States)

    Anson, J G

    1989-03-01

    Two experiments examined the effect of altering the moment of inertia within an anatomical unit on simple reaction time (SRT), premotor time (PMT), and motor time (MOT) during the initiation of a discrete rapid movement. In Experiment 1 (N = 14), moment of inertia of the forearm was increased with the addition of a weighted cuff fastened around the wrist. In Experiment 2 (N = 7), moment of inertia was altered by the addition of a weighted sleeve to the index finger prior to rapid extension of the digit. Results from both experiments were unequivocal. An increase in the moment of inertia resulted in a significant increase in SRT and MOT but had no significant effect on PMT. Within selected anatomical unites (forearm and index finger), an increase in the moment of inertia does not appear to require additional neuromotor programming time but does influence the overall duration of response initiation.

  17. Dual wire welding torch and method

    Science.gov (United States)

    Diez, Fernando Martinez; Stump, Kevin S.; Ludewig, Howard W.; Kilty, Alan L.; Robinson, Matthew M.; Egland, Keith M.

    2009-04-28

    A welding torch includes a nozzle with a first welding wire guide configured to orient a first welding wire in a first welding wire orientation, and a second welding wire guide configured to orient a second welding wire in a second welding wire orientation that is non-coplanar and divergent with respect to the first welding wire orientation. A method of welding includes moving a welding torch with respect to a workpiece joint to be welded. During moving the welding torch, a first welding wire is fed through a first welding wire guide defining a first welding wire orientation and a second welding wire is fed through a second welding wire guide defining a second welding wire orientation that is divergent and non-coplanar with respect to the first welding wire orientation.

  18. Explicit Exact Formulas for the 3-D Tetrahedron Inertia Tensor in Terms of its Vertex Coordinates

    Directory of Open Access Journals (Sweden)

    F. Tonon

    2005-01-01

    Full Text Available The inertia tensor of a tetrahedron is composed of its moments of inertia. This study presents explicit exact formulas for the moments of inertia of a 3-D tetrahedron as simple polynomials of its vertex coordinates.

  19. Challenges to Resistance Welding

    DEFF Research Database (Denmark)

    Song, Quanfeng

    This report originates from the compulsory defense during my Ph.D. study at the Technical University of Denmark. Resistance welding is an old and well-proven technology. Yet the emergence of more and more new materials, new designs, invention off new joining techniques, and more stringent...... requirement in quality have imposed challenges to the resistance welding. More some research and development have to be done to adapt the old technology to the manufacturing industry of the 21st century. In the 1st part of the report, the challenging factors to the resistance welding are reviewed. Numerical...... simulation of resistance welding has been under development for many years. Yet it is no easy to make simulation results reliable and accurate because of the complexity of resistance welding process. In the 2nd part of the report numerical modeling of resistance welding is reviewed, some critical factors...

  20. Ultrasonic Stir Welding

    Science.gov (United States)

    Nabors, Sammy

    2015-01-01

    NASA Marshall Space Flight Center (MSFC) developed Ultrasonic Stir Welding (USW) to join large pieces of very high-strength metals such as titanium and Inconel. USW, a solid-state weld process, improves current thermal stir welding processes by adding high-power ultrasonic (HPU) energy at 20 kHz frequency. The addition of ultrasonic energy significantly reduces axial, frictional, and shear forces; increases travel rates; and reduces wear on the stir rod, which results in extended stir rod life. The USW process decouples the heating, stirring, and forging elements found in the friction stir welding process allowing for independent control of each process element and, ultimately, greater process control and repeatability. Because of the independent control of USW process elements, closed-loop temperature control can be integrated into the system so that a constant weld nugget temperature can be maintained during welding.

  1. Challenges to Resistance Welding

    DEFF Research Database (Denmark)

    Song, Quanfeng

    This report originates from the compulsory defense during my Ph.D. study at the Technical University of Denmark. Resistance welding is an old and well-proven technology. Yet the emergence of more and more new materials, new designs, invention off new joining techniques, and more stringent...... requirement in quality have imposed challenges to the resistance welding. More some research and development have to be done to adapt the old technology to the manufacturing industry of the 21st century. In the 1st part of the report, the challenging factors to the resistance welding are reviewed. Numerical...... simulation of resistance welding has been under development for many years. Yet it is no easy to make simulation results reliable and accurate because of the complexity of resistance welding process. In the 2nd part of the report numerical modeling of resistance welding is reviewed, some critical factors...

  2. Manganese Content Control in Weld Metal During MAG Welding

    Science.gov (United States)

    Chinakhov, D. A.; Chinakhova, E. D.; Sapozhkov, A. S.

    2016-08-01

    The influence of the welding current and method of gas shielding in MAG welding on the content of manganese is considered in the paper. Results of study of the welded specimens of steels 45 when applying welding wire of different formulas and different types of gas shielding (traditional shielding and double-jet shielding) are given. It is found that in MAG welding the value of the welding current and the speed of the gas flow from the welding nozzle have a considerable impact on the chemical composition of the weld metal. The consumable electrode welding under double-jet gas shielding provides the directed gas-dynamics in the welding area and enables controlling the electrode metal transfer and the chemical composition of a weld.

  3. Infrared thermography for monitoring heat generation in a linear friction welding process of Ti6Al4V alloy

    Science.gov (United States)

    Maio, L.; Liberini, M.; Campanella, D.; Astarita, A.; Esposito, S.; Boccardi, S.; Meola, C.

    2017-03-01

    The increasing use of titanium alloys in a wider range of applications requires the development of new techniques and processes capable to decrease production costs and manufacturing times. In this regard welding and other joining techniques play an important role. Today, solid state friction joining processes, such as friction stir welding, friction spot welding, inertia friction welding, continuous-drive friction welding and linear friction welding (LFW), represent promising methods for part manufacturing. They allow for joining at temperature essentially below the melting point of the base materials being joined, without the addition of filler metal. However, the knowledge of temperature is essential to understand and model the phenomena involved in metal welding. A global measured value represents only a clue of the heat generation during the process; while, a deep understanding of welding thermal aspects requires temperature field measurement. This paper is focused on the use of infrared thermography applied to the linear friction welding process of Ti6Al4V alloy. The attention is concentrated on thermal field that develops on the outer wall of the two parts to be joined (i.e. heat generated in the friction zone), and on the maximum temperature that characterizes the process before and after the flash formation.

  4. Studies of welded joints

    Directory of Open Access Journals (Sweden)

    J. M. Krupa

    2010-07-01

    Full Text Available Studies of a welded joint were described. The joint was made as a result of the reconstruction of a truss and one of the possible means to make a repair. The studies were of a simulation character and were targeted at the detection of welding defects and imperfections thatshould be eliminated in a real structure. A model was designed and on this model the tests and examinations were carried out. The modelwas made under the same conditions as the conditions adopted for repair. It corresponded to the real object in shape and dimensions, and in the proposed technique of welding and welding parameters. The model was composed of five plates joined together with twelve beads.The destructive and non-destructive tests were carried out; the whole structure and the respective welds were also examined visually. Thedefects and imperfections in welds were detected by surface methods of inspection, penetration tests and magnetic particle flaw detection.The model of the welded joint was prepared by destructive methods, a technique that would never be permitted in the case of a realstructure. For the investigations it was necessary to cut out the specimens from the welded joint in direction transverse to the weld run. The specimens were subjected to metallographic examinations and hardness measurements. Additionally, the joint cross-section was examined by destructive testing methods to enable precise determination of the internal defects and imperfections. The surface methods were applied again, this time to determine the severity of welding defects. The analysis has proved that, fabricated under proper conditions and with parameters of the welding process duly observed, the welded joint has good properties and repairs of this type are possible in practice.

  5. Explosive Welding of Pipes

    Science.gov (United States)

    Drennov, Oleg; Drennov, Andrey; Burtseva, Olga

    2013-06-01

    For connection by welding it is suggested to use the explosive welding method. This method is rather new. Nevertheless, it has become commonly used among the technological developments. This method can be advantageous (saving material and physical resources) comparing to its statical analogs (electron-beam welding, argon-arc welding, plasma welding, gas welding, etc.), in particular, in hard-to-reach areas due to their geographic and climatic conditions. Explosive welding of cylindrical surfaces is performed by launching of welded layer along longitudinal axis of construction. During this procedure, it is required to provide reliable resistance against radial convergent strains. The traditional method is application of fillers of pipe cavity, which are dense cylindrical objects having special designs. However, when connecting pipes consecutively in pipelines by explosive welding, removal of the fillers becomes difficult and sometimes impossible. The suggestion is to use water as filler. The principle of non-compressibility of liquid under quasi-dynamic loading is used. In one-dimensional gasdynamic and elastic-plastic calculations we determined non-deformed mass of water (perturbations, which are moving in the axial direction with sound velocity, should not reach the layer end boundaries for 5-7 circulations of shock waves in the radial direction). Linear dimension of the water layer from the zone of pipe coupling along axis in each direction is >= 2R, where R is the internal radius of pipe.

  6. Explosive welding of pipes

    Energy Technology Data Exchange (ETDEWEB)

    Drennov, O.; Burtseva, O.; Kitin, A. [Russian Federal Nuclear Center, Sarov (Russian Federation)

    2006-08-15

    Arrangement of pipelines for the transportation of oil and gas is a complicated problem. In this paper it is suggested to use the explosive welding method to weld pipes together. This method is rather new. This method can be advantageous (saving material and physical resources) comparing to its static analogs (electron-beam welding, argon-arc welding, plasma welding, gas welding, etc.), in particular, in hard-to-reach areas due to their geographic and climatic conditions. We suggest to perform explosive welding according to the following scheme: the ends of the 2 pipes are connected, the external surfaces are kept at a similar level. A cylindrical steel layer of diameter larger than the pipe diameter is set around the pipe joint and an explosive charge is placed on its external surface. The basic problem is the elimination of strains and reduction of pipe diameter in the area of the dynamic effect. The suggestion is to use water as filler: the volume of pipes in the area adjacent to the zone of explosive welding is totally filled with water. The principle of non-compressibility of liquid under quasi-dynamic loading is used. In one-dimensional gas dynamic and elastic-plastic calculations we determined non-deformed mass of water. Model experiments with pipes having radii R = 57 mm confirmed results of the calculations and the possibility in principle to weld pipes by explosion with use of water as filler.

  7. High-Capacity Photorefractive Neural Network Implementing a Kohonen Topological Map

    Science.gov (United States)

    Frauel, Yann; Pauliat, Gilles; Villing, André; Roosen, Gérald

    2001-10-01

    We designed and built a high-capacity neural network based on volume holographic interconnections in a photorefractive crystal. We used this system to implement a Kohonen topological map. We describe and justify our optical setup and present some experimental results of self-organization in the learning database.

  8. High-powered conveyor systems: long distance, downhill, open-pit, and high capacity conveyors

    Energy Technology Data Exchange (ETDEWEB)

    Pelzer, H.K.

    1978-01-01

    Paper indicates the conditions under which belt conveyors are superior to other forms of transport, the limitations of these conveyors. Long distance, downhill, open-pit and high capacity conveyor installations are described, including a 60-mile long conveyor in the Sahara.

  9. A Novel and Simple Means to Estimate Asteroid Thermal Inertia

    Science.gov (United States)

    Drube, Line; Harris, Alan

    2016-10-01

    Calculating accurate values of thermal inertia for asteroids is a difficult process requiring a shape model, thermal-infrared observations of the object obtained over broad ranges of rotation period and aspect angle, and detailed thermophysical modeling. Consequently, reliable thermal inertia values are currently available for relatively few asteroids. On the basis of simple asteroid thermal modeling we have developed an empirical relationship enabling the thermal inertia of an asteroid to be estimated given adequate measurements of its thermal-infrared continuum and knowledge of its spin vector. In particular, our thermal-inertia estimator can be applied to hundreds of objects in the WISE cryogenic archive (limited by the availability of spin vectors). To test the accuracy of our thermal-inertia estimator we have used it to estimate thermal inertia for near-Earth asteroids, main-belt asteroids, Centaurs, and trans-Neptunian objects with known thermal inertia values derived from detailed thermophysical modeling. In nearly all cases the estimates agree within the error bars with the values derived from thermophysical modeling.

  10. Discovery of Spin-Rate-Dependent Asteroid Thermal Inertia

    Science.gov (United States)

    Harris, Alan; Drube, Line

    2016-10-01

    Knowledge of the surface thermal inertia of an asteroid can provide insight into surface structure: porous material has a lower thermal inertia than rock. Using WISE/NEOWISE data and our new asteroid thermal-inertia estimator we show that the thermal inertia of main-belt asteroids (MBAs) appears to increase with spin period. Similar behavior is found in the case of thermophysically-modeled thermal inertia values of near-Earth objects (NEOs). We interpret our results in terms of rapidly increasing material density and thermal conductivity with depth, and provide evidence that thermal inertia increases by factors of 10 (MBAs) to 20 (NEOs) within a depth of just 10 cm. On the basis of a picture of depth-dependent thermal inertia our results suggest that, in general, thermal inertia values representative of solid rock are reached some tens of centimeters to meters below the surface in the case of MBAs (the median diameter in our dataset = 24 km). In the case of the much smaller (km-sized) NEOs a thinner porous surface layer is indicated, with large pieces of solid rock possibly existing just a meter or less below the surface. These conclusions are consistent with our understanding from in-situ measurements of the surfaces of the Moon, and a few asteroids, and suggest a very general picture of rapidly changing material properties in the topmost regolith layers of asteroids. Our results have important implications for calculations of the Yarkovsky effect, including its perturbation of the orbits of potentially hazardous objects and those of asteroid family members after the break-up event. Evidence of a rapid increase of thermal inertia with depth is also an important result for studies of the ejecta-enhanced momentum transfer of impacting vehicles ("kinetic impactors") in planetary defense.

  11. Improved diffusion welding and roll welding of titanium alloys

    Science.gov (United States)

    Holko, K. H.

    1973-01-01

    Auto-vacuum cleaning technique was applied to titanium parts prior to welding. This provides oxide-free welding surfaces. Diffusion welding can be accomplished in as little as five minutes of hot pressing. Roll welding can be accomplished with only ten percent deformation.

  12. A Review: Welding Of Dissimilar Metal Alloys by Laser Beam Welding & Friction Stir Welding Techniques

    Directory of Open Access Journals (Sweden)

    Ms. Deepika Harwani

    2014-12-01

    Full Text Available Welding of dissimilar metals has attracted attention of the researchers worldwide, owing to its many advantages and challenges. There is no denial in the fact that dissimilar welded joints offer more flexibility in the design and production of the commercial and industrial components. Many welding techniques have been analyzed to join dissimilar metal combinations. The objective of this paper is to review two such techniques – Laser welding and Friction stir welding. Laser beam welding, a high power density and low energy-input process, employs a laser beam to produce welds of dissimilar materials. Friction stir welding, a solid-state joining process, is also successfully used in dissimilar welding applications like aerospace and ship building industries. This paper summarizes the trends and advances of these two welding processes in the field of dissimilar welding. Future aspects of the study are also discussed.

  13. Inertia Identification and PI Parameter Tuning of PMSM Servo Drives

    Science.gov (United States)

    Lei, Huang

    2017-05-01

    The goal of this paper is to improve the performance of permanent magnet synchronous motor(PMSM) servo system by identification of the inertia parameter and auto-tuning of PI parameters. The method relies on the speed acceleration and deceleration response produced by speed ramp signals applied to a speed-controlled servo. The proposed method relies on simple numerical calculations, thus make the proposed scheme more practical. After the knowledge of the inertia parameter, the tuning of the speed control loop can be performed. The experimental results verified that the proposed identification scheme can estimate inertia parameters accurately and effectively and the control system tuned can achieve good dynamic performance.

  14. On Mach's principle: Inertia as gravitation

    CERN Document Server

    Martín, J; Tiemblo, A; Ranada, Antonio F.

    2007-01-01

    In order to test the validity of Mach's principle, we calculate the action of the entire universe on a test mass in its rest frame, which is an acceleration ${\\bf g}^*$. We show the dependence of the inertia principle on the lapse and the shift. Using the formalism of linearized gravitation, we obtain the non-relativistic limit of ${\\bf g}^*$ in terms of two integrals. We follow then two approaches. In the first one, these integrals are calculated in the actual time section $t=t_0$ up to the distance $R_U=ct_0$. In the more exact and satisfactory second approach, they are calculated over the past light cone using the formalism of the retarded potentials. The aim is to find whether the acceleration $\\dot{\\bf v}$ in the LHS of Newton's second law can be interpreted as a reactive acceleration, in other words, as minus the acceleration of gravity ${\\bf g}^*$ in the rest frame of the accelerated particle ({\\it i. e.} to know whether or not ${\\bf g}^*=-\\dot{\\bf v}$). The results strongly support Mach's idea since t...

  15. Fine welding with lasers.

    Science.gov (United States)

    MacLellan, D

    2008-01-01

    The need for micro joining metallic alloys for surgical instruments, implants and advanced medical devices is driving a rapid increase in the implementation of laser welding technology in research, development and volume production. This article discusses the advantages of this welding method and the types of lasers used in the process.

  16. Simulation of welding

    Institute of Scientific and Technical Information of China (English)

    Chuan-Song WU; Michael RETHMEIER; Christopher SCHWENK

    2011-01-01

    @@ Welding has become the most important materials processing technology in manufacturing, and has critical effects on the quality, reliability and life of products as well as production cost, efficiency and response speed to market.As various kinds of high performance metallic materials are widely used in engineering, there are more demands in manufacturing industry for advanced welding technology.

  17. Vacuum Gas Tungsten Arc Welding

    Science.gov (United States)

    Weeks, J. L.; Todd, D. T.; Wooten, J. R.

    1997-01-01

    A two-year program investigated vacuum gas tungsten arc welding (VGTAW) as a method to modify or improve the weldability of normally difficult-to-weld materials. After a vacuum chamber and GTAW power supply were modified, several difficult-to-weld materials were studied and key parameters developed. Finally, Incoloy 903 weld overlays were produced without microfissures.

  18. Alternating-Polarity Arc Welding

    Science.gov (United States)

    Schwinghamer, R. J.

    1987-01-01

    Brief reversing polarity of welding current greatly improves quality of welds. NASA technical memorandum recounts progress in art of variable-polarity plasma-arc (VPPA) welding, with emphasis on welding of aluminum-alloy tanks. VPPA welders offer important advantages over conventional single-polarity gas/tungsten arc welders.

  19. The effect of welding fixtures on welding distortions

    OpenAIRE

    2007-01-01

    Purpose: of this paper is to examine the effect of welding fixture used to prevent the distortions duringcooling process utilizing a robot controlled gas metal arc welding method on cooling rate and distortions ofwelded structures.Design/methodology/approach: Using a specially designed welding fixture for a welded steel structure, sixdifferent types of AISI 1020 steel specimens are tested in three different welding speeds and two differentcooling conditions either at fixture or without using ...

  20. Multispot fiber laser welding

    DEFF Research Database (Denmark)

    Schutt Hansen, Klaus

    This dissertation presents work and results achieved in the field of multi beam fiber laser welding. The project has had a practical approach, in which simulations and modelling have been kept at a minimum. Different methods to produce spot patterns with high power single mode fiber lasers have...... been possible to control the welding width in incremental steps by adding more beams in a row. The laser power was used to independently control the keyhole and consequently the depth of fusion. An example of inline repair of a laser weld in butt joint configuration was examined. Zinc powder was placed...... in the weld causing expulsion of the melt pool. Trailing beams were applied to melt additional material and ensure a melt pool. The method showed good results for increasing tolerances to impurities and reduction of scrapped parts from blowouts during laser welding....

  1. Rheomorphism of welded tuffs

    Science.gov (United States)

    Wolff, J. A.; Wright, J. V.

    1981-05-01

    Peralkaline welded tuffs from the islands of Gran Canaria, Canary Islands, and Pantelleria, Italy, show abundant evidence for post-depositional flow. It is demonstrated that rheomorphism, or secondary mass flowage, can occur in welded tuffs of ignimbrite and air-fall origin. The presence of a linear fabric is taken as the diagnostic criterion for the recognition of the process. Deposition on a slope is an essential condition for the development of rheomorphism after compaction and welding. Internal structures produced during rheomorphic flow can be studied by the methods of structural geology and show similar dispositions to comparable features in sedimentary slump sheets. It is shown that secondary flowage can occur in welded tuffs emplaced on gentle slopes, provided that the apparent viscosity of the magma is sufficiently low. Compositional factors favor the development of rheomorphism in densely welded tuffs of peralkaline type.

  2. A new measuring technique of soil thermal inertia

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Thermal inertia is the function of substance density,heat capacity and heat diffusivity,and is an important parameter for researching the process of surface heat balance using remote sensing technique.In this paper,using soil heat plates,infrared thermometer,data logger and other instruments,by man-controlled changing the solar radiation status on the soil samples,the authors gave a new method to measure soil thermal inertia.Using the continuously surveying data of soil heat flux and infrared radiation temperature,thermal inertia can be calculated easily.Based on the thermal inertia calculation of three soil samples with different water content,good results were abtained by the authors,so this method is feasible.Meanwhile,this measuring technique is also a new attempt.

  3. A new measuring technique of soil thermal inertia

    Institute of Scientific and Technical Information of China (English)

    孙晓敏; 朱治林; 唐新斋; 苏红波; 张仁华

    2000-01-01

    Thermal inertia is the function of substance density, heat capacity and heat diffusivity, and is an important parameter for researching the process of surface heat balance using remote sensing technique. In this paper, using soil heat plates, infrared thermometer, data logger and other instruments, by man-controlled changing the solar radiation status on the soil samples, the authors gave a new method to measure soil thermal inertia. Using the continuously surveying data of soil heat flux and infrared radiation temperature, thermal inertia can be calculated easily. Based on the thermal inertia calculation of three soil samples with different water content, good results were abtained by the authors, so this method is feasible. Meanwhile, this measuring technique is also a new attempt.

  4. On the moment of inertia of a proto neutron star

    Institute of Scientific and Technical Information of China (English)

    ZHAO Xian-Feng; ZHANG Hua; JIA Huan-Yu

    2010-01-01

    The influences of σ*and Φ mesons,temperature and coupling constants of nucleons on the moment of inertia of the proto neutron star(PNS)are examined in the framework of relativistic mean field theory for the baryon octet {n,p,∧,∑-,∑0,∑+,Ξ-,Ξ0} system.It is found that,compared with that without consideringσ*and Φ mesons,the moment of inertia decreases.It is also found that the higher the temperature,the larger the incompressibility and symmetry energy coefficient,and the larger the moment of inertia of a PNS.The influence of temperature and coupling constants of the nucleons on the moment of inertia of a PNS is larger than that of the σ*and Φ mesons.

  5. Galaxy rotations from quantised inertia and visible matter only

    Science.gov (United States)

    McCulloch, M. E.

    2017-09-01

    It is shown here that a model for inertial mass, called quantised inertia, or MiHsC (Modified inertia by a Hubble-scale Casimir effect) predicts the rotational acceleration of the 153 good quality galaxies in the SPARC dataset (2016 AJ 152 157), with a large range of scales and mass, from just their visible baryonic matter, the speed of light and the co-moving diameter of the observable universe. No dark matter is needed. The performance of quantised inertia is comparable to that of MoND, yet it needs no adjustable parameter. As a further critical test, quantised inertia uniquely predicts a specific increase in the galaxy rotation anomaly at higher redshifts. This test is now becoming possible and new data shows that galaxy rotational accelerations do increase with redshift in the predicted manner, at least up to Z=2.2.

  6. Application of Inertia Ellipse in Code Marker Matching

    Institute of Scientific and Technical Information of China (English)

    XU Fang; JIANG Weiwei; HE Qing; HU Xiaobin

    2010-01-01

    In close-range photogrammetry, 3D information acquisition is based on image matching. The application of code marker helps to improve the level of automatic matching and the matching accuracy. This paper inyestigates the application of inertia ellipse algorithm to code marker matching. We can calculate the inertia ellipse of a target with a certain boundary. First, the method is applied to a single code marker; the angle and scaling are valid. Then, the paper introduces the multi code markers matching method by the inertia ellipse. Rotation and scaling changes of homonymy images can be calculated by inertia ellipse algorithm. These parameters can be used for code marker matching in arbitrary attitude close-range photogrammetry.

  7. DETERMINATI>N OF MOMENTS OF INERTIA: A FACILITIES STUDY,

    Science.gov (United States)

    which can be accommodated by the facility. It is concluded that the amount of manual manipulacion required for moment of inertia 4easurements can be reduced by improving che usefulness of present equipment. (Author)

  8. Estimation of Parameters Obtained by Electrochemical Impedance Spectroscopy on Systems Containing High Capacities

    Directory of Open Access Journals (Sweden)

    Mirjana Rajčić Vujasinović

    2009-09-01

    Full Text Available Electrochemical systems with high capacities demand devices for electrochemical impedance spectroscopy (EIS with ultra-low frequencies (in order of mHz, that are almost impossible to accomplish with analogue techniques, but this becomes possible by using a computer technique and accompanying digital equipment. Recently, an original software and hardware for electrochemical measurements, intended for electrochemical systems exhibiting high capacities, such as supercapacitors, has been developed. One of the included methods is EIS. In this paper, the method of calculation of circuit parameters from an EIS curve is described. The results of testing on a physical model of an electrochemical system, constructed of known elements (including a 1.6 F capacitor in a defined arrangement, proved the validity of the system and the method.

  9. High-capacity quantum key distribution using Chebyshev-map values corresponding to Lucas numbers coding

    Science.gov (United States)

    Lai, Hong; Orgun, Mehmet A.; Pieprzyk, Josef; Li, Jing; Luo, Mingxing; Xiao, Jinghua; Xiao, Fuyuan

    2016-08-01

    We propose an approach that achieves high-capacity quantum key distribution using Chebyshev-map values corresponding to Lucas numbers coding. In particular, we encode a key with the Chebyshev-map values corresponding to Lucas numbers and then use k-Chebyshev maps to achieve consecutive and flexible key expansion and apply the pre-shared classical information between Alice and Bob and fountain codes for privacy amplification to solve the security of the exchange of classical information via the classical channel. Consequently, our high-capacity protocol does not have the limitations imposed by orbital angular momentum and down-conversion bandwidths, and it meets the requirements for longer distances and lower error rates simultaneously.

  10. High-Capacity Hydrogen-Based Green-Energy Storage Solutions For The Grid Balancing

    Science.gov (United States)

    D'Errico, F.; Screnci, A.

    One of the current main challenges in green-power storage and smart grids is the lack of effective solutions for accommodating the unbalance between renewable energy sources, that offer intermittent electricity supply, and a variable electricity demand. Energy management systems have to be foreseen for the near future, while they still represent a major challenge. Integrating intermittent renewable energy sources, by safe and cost-effective energy storage systems based on solid state hydrogen is today achievable thanks to recently some technology breakthroughs. Optimized solid storage method made of magnesium-based hydrides guarantees a very rapid absorption and desorption kinetics. Coupled with electrolyzer technology, high-capacity storage of green-hydrogen is therefore practicable. Besides these aspects, magnesium has been emerging as environmentally friend energy storage method to sustain integration, monitoring and control of large quantity of GWh from high capacity renewable generation in the EU.

  11. High-capacity three-party quantum secret sharing with superdense coding

    Institute of Scientific and Technical Information of China (English)

    Gu Bin; Li Chuan-Qi; Xu Fei; Chen Yu-Lin

    2009-01-01

    This paper presents a scheme for high-capacity three-party quantum secret sharing with quantum superdense coding, following some ideas in the work by Liu et al (2002 Phys. Rev. A 65 022304) and the quantum secret sharing scheme by Deng et al (2008 Phys. Left. A 372 1957). Instead of using two sets of nonorthogonal states, the boss Alice needs only to prepare a sequence of Einstein-Podolsky-Rosen pairs in d-dimension. The two agents Bob and Charlie encode their information with dense coding unitary operations, and security is checked by inserting decoy photons. The scheme has a high capacity and intrinsic efficiency as each pair can carry 21bd bits of information, and almost all the pairs can be used for carrying useful information.

  12. Radiation and temperature effects on electronic components investigated under the CSTI high capacity power project

    Science.gov (United States)

    Schwarze, Gene E.; Niedra, Janis M.; Frasca, Albert J.; Wieserman, William R.

    1993-01-01

    The effects of nuclear radiation and high temperature environments must be fully known and understood for the electronic components and materials used in both the Power Conditioning and Control subsystem and the reactor Instrumentation and Control subsystem of future high capacity nuclear space power systems. This knowledge is required by the designer of these subsystems in order to develop highly reliable, long-life power systems for future NASA missions. A review and summary of the experimental results obtained for the electronic components and materials investigated under the power management element of the Civilian Space Technology Initiative (CSTI) high capacity power project are presented: (1) neutron, gamma ray, and temperature effects on power semiconductor switches, (2) temperature and frequency effects on soft magnetic materials; and (3) temperature effects on rare earth permanent magnets.

  13. High-capacity quantum key distribution using Chebyshev-map values corresponding to Lucas numbers coding

    Science.gov (United States)

    Lai, Hong; Orgun, Mehmet A.; Pieprzyk, Josef; Li, Jing; Luo, Mingxing; Xiao, Jinghua; Xiao, Fuyuan

    2016-11-01

    We propose an approach that achieves high-capacity quantum key distribution using Chebyshev-map values corresponding to Lucas numbers coding. In particular, we encode a key with the Chebyshev-map values corresponding to Lucas numbers and then use k-Chebyshev maps to achieve consecutive and flexible key expansion and apply the pre-shared classical information between Alice and Bob and fountain codes for privacy amplification to solve the security of the exchange of classical information via the classical channel. Consequently, our high-capacity protocol does not have the limitations imposed by orbital angular momentum and down-conversion bandwidths, and it meets the requirements for longer distances and lower error rates simultaneously.

  14. Estimation of parameters obtained by electrochemical impedance spectroscopy on systems containing high capacities.

    Science.gov (United States)

    Stević, Zoran; Vujasinović, Mirjana Rajčić; Radunović, Milan

    2009-01-01

    Electrochemical systems with high capacities demand devices for electrochemical impedance spectroscopy (EIS) with ultra-low frequencies (in order of mHz), that are almost impossible to accomplish with analogue techniques, but this becomes possible by using a computer technique and accompanying digital equipment. Recently, an original software and hardware for electrochemical measurements, intended for electrochemical systems exhibiting high capacities, such as supercapacitors, has been developed. One of the included methods is EIS. In this paper, the method of calculation of circuit parameters from an EIS curve is described. The results of testing on a physical model of an electrochemical system, constructed of known elements (including a 1.6 F capacitor) in a defined arrangement, proved the validity of the system and the method.

  15. Estimation of Parameters Obtained by Electrochemical Impedance Spectroscopy on Systems Containing High Capacities

    Science.gov (United States)

    Stević, Zoran; Vujasinović, Mirjana Rajčić; Radunović, Milan

    2009-01-01

    Electrochemical systems with high capacities demand devices for electrochemical impedance spectroscopy (EIS) with ultra-low frequencies (in order of mHz), that are almost impossible to accomplish with analogue techniques, but this becomes possible by using a computer technique and accompanying digital equipment. Recently, an original software and hardware for electrochemical measurements, intended for electrochemical systems exhibiting high capacities, such as supercapacitors, has been developed. One of the included methods is EIS. In this paper, the method of calculation of circuit parameters from an EIS curve is described. The results of testing on a physical model of an electrochemical system, constructed of known elements (including a 1.6 F capacitor) in a defined arrangement, proved the validity of the system and the method. PMID:22400000

  16. Welding method, and welding device for use therein, and method of analysis for evaluating welds

    NARCIS (Netherlands)

    Aendenroomer, A.J.; Den Ouden, G.; Xiao, Y.H.; Brabander, W.A.J.

    1995-01-01

    Described is a method of automatically welding pipes, comprising welding with a pulsation welding current and monitoring, by means of a sensor, the variations occurring in the arc voltage caused by weld pool oscillations. The occurrence of voltage variations with only frequency components below 100

  17. Thermoplastic welding apparatus and method

    Energy Technology Data Exchange (ETDEWEB)

    Matsen, Marc R.; Negley, Mark A.; Geren, William Preston; Miller, Robert James

    2017-03-07

    A thermoplastic welding apparatus includes a thermoplastic welding tool, at least one tooling surface in the thermoplastic welding tool, a magnetic induction coil in the thermoplastic welding tool and generally encircling the at least one tooling surface and at least one smart susceptor in the thermoplastic welding tool at the at least one tooling surface. The magnetic induction coil is adapted to generate a magnetic flux field oriented generally parallel to a plane of the at least one smart susceptor.

  18. Laser forming and welding processes

    CERN Document Server

    Yilbas, Bekir Sami; Shuja, Shahzada Zaman

    2013-01-01

    This book introduces model studies and experimental results associated with laser forming and welding such as laser induced bending, welding of sheet metals, and related practical applications. The book provides insight into the physical processes involved with laser forming and welding. The analytical study covers the formulation of laser induced bending while the model study demonstrates the simulation of bending and welding processes using the finite element method. Analytical and numerical solutions for laser forming and welding problems are provided.

  19. Guidelines for Friction Stir Welding

    Science.gov (United States)

    2011-03-29

    in a large void at the termination point of the weld, the effects the exit hole will have on structural integrity must be considered. The...3.6 Cavity. A void -type discontinuity within a solid-state weld. See Figure 3.4. 3.7 Complex weld joint. A continuous weld...except as affected by corner radii. 3.61 Underfill . A depression resulting when the weld face is below the adjacent parent material surface. See

  20. Determinacy, Stock Market Dynamics and Monetary Policy Inertia

    DEFF Research Database (Denmark)

    Pfajfar, Damjan; Santoro, Emiliano

    the vantage of equilibrium uniqueness. We show that this reaction function is isomorphic to a rule with an interest rate smoothing term, whose magnitude increases in the degree of aggressiveness towards asset prices growth. As shown by Bullard and Mitra (2007, Determinacy, learnability, and monetary policy...... inertia, Journal of Money, Credit and Banking 39, 1177-1212) this feature of monetary policy inertia can help at alleviating problems of indeterminacy....

  1. Pairing Field and Moments of Inertia of Superdeformed Nuclei

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The dynamic moments of inertia of the experimental superdeformed bands observed in the A=190,150 and 60~80 mass regions were systematically analyzed. By getting together the different massregions the dramatic features of the dynamic moments of inertia were found and explained based on thecalculations of the pairing fields of SD nuclei with the anisotropic harmonic oscillator quadrupole pairingHartree-Fock-Bogolyubor model. The gradually rising behavior of J2 indicates that the SD states in the

  2. Pairing Field and Moments of Inertia of Superdeformed Nuclei

    Institute of Scientific and Technical Information of China (English)

    陈永静; 陈永寿; 陈辅新

    2002-01-01

    We have systematically analysed the dynamic moments of inertia of the experimental superdeformed (SD)bands observed in the A = 190, 150 and 60-80 mass regions as functions of rotational frequency. By combining the different mass regions, the dramatic features of the dynamic moments of inertia were found and explained based on the calculations of the pairing fields of SD nuclei with the anisotropic harmonic oscillator quadrupole pairing Hartree-Fock-Bogoliubov model.

  3. Probing the origin of inertia behind spacetime deformation

    OpenAIRE

    Ter-Kazarian, Gagik

    2011-01-01

    To investigate the origin and nature of inertia, we introduce a new concept of hypothetical 2D, so-called, "master-space" (MS), subject to certain rules. The MS, embedded in the background 4D-spacetime, is an indispensable individual companion to the particle of interest, without relation to every other particle. We argue that a deformation/(distortion of local internal properties) of MS is the origin of inertia. With this perspective in sight, we construct the alternative relativistic theory...

  4. Overview of space power electronic's technology under the CSTI High Capacity Power Program

    Science.gov (United States)

    Schwarze, Gene E.

    The Civilian Space Technology Initiative (CSTI) is a NASA Program targeted at the development of specific technologies in the areas of transportation, operations and science. Each of these three areas consists of major elements and one of the operation's elements is the High Capacity Power element. The goal of this element is to develop the technology base needed to meet the long duration, high capacity power requirements for future NASA initiatives. The High Capacity Power element is broken down into several subelements that includes energy conversion in the areas of the free piston Stirling power converter and thermoelectrics, thermal management, power management, system diagnostics, and environmental compatibility and system's lifetime. A recent overview of the CSTI High capacity Power element and a description of each of the program's subelements is given by Winter (1989). The goals of the Power Management subelement are twofold. The first is to develop, test, and demonstrate high temperature, radiation-resistant power and control components and circuits that will be needed in the Power Conditioning, Control and Transmission (PCCT) subsystem of a space nuclear power system. The results obtained under this goal will also be applicable to the instrumentation and control subsystem of a space nuclear reactor. These components and circuits must perform reliably for lifetimes of 7-10 years. The second goal is to develop analytical models for use in computer simulations of candidate PCCT subsystems. Circuits which will be required for a specific PCCT subsystem will be designed and built to demonstrate their performance and, also, to validate the analytical models and simulations. The tasks under the Power Management subelement will now be described in terms of objectives, approach and present status of work.

  5. Topology Management Algorithms for Large Scale Aerial High Capacity Directional Networks

    Science.gov (United States)

    2016-11-01

    Introduction of classes of topology management algo- rithms and example implementations of each • Performance evaluation of the algorithms in 2 example relevant...Topology Management Algorithms for Large-Scale Aerial High Capacity Directional Networks Joy Wang, Thomas Shake, Patricia Deutsch, Andrea Coyle, Bow...airborne backbone network is large- scale topology management of directional links in a dynamic environment. In this paper, we present several

  6. Overview of space power electronic's technology under the CSTI High Capacity Power Program

    Science.gov (United States)

    Schwarze, Gene E.

    1994-01-01

    The Civilian Space Technology Initiative (CSTI) is a NASA Program targeted at the development of specific technologies in the areas of transportation, operations and science. Each of these three areas consists of major elements and one of the operation's elements is the High Capacity Power element. The goal of this element is to develop the technology base needed to meet the long duration, high capacity power requirements for future NASA initiatives. The High Capacity Power element is broken down into several subelements that includes energy conversion in the areas of the free piston Stirling power converter and thermoelectrics, thermal management, power management, system diagnostics, and environmental compatibility and system's lifetime. A recent overview of the CSTI High capacity Power element and a description of each of the program's subelements is given by Winter (1989). The goals of the Power Management subelement are twofold. The first is to develop, test, and demonstrate high temperature, radiation-resistant power and control components and circuits that will be needed in the Power Conditioning, Control and Transmission (PCCT) subsystem of a space nuclear power system. The results obtained under this goal will also be applicable to the instrumentation and control subsystem of a space nuclear reactor. These components and circuits must perform reliably for lifetimes of 7-10 years. The second goal is to develop analytical models for use in computer simulations of candidate PCCT subsystems. Circuits which will be required for a specific PCCT subsystem will be designed and built to demonstrate their performance and, also, to validate the analytical models and simulations. The tasks under the Power Management subelement will now be described in terms of objectives, approach and present status of work.

  7. Silicon oxide based high capacity anode materials for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Haixia; Han, Yongbong; Masarapu, Charan; Anguchamy, Yogesh Kumar; Lopez, Herman A.; Kumar, Sujeet

    2017-03-21

    Silicon oxide based materials, including composites with various electrical conductive compositions, are formulated into desirable anodes. The anodes can be effectively combined into lithium ion batteries with high capacity cathode materials. In some formulations, supplemental lithium can be used to stabilize cycling as well as to reduce effects of first cycle irreversible capacity loss. Batteries are described with surprisingly good cycling properties with good specific capacities with respect to both cathode active weights and anode active weights.

  8. Elucidation of laser welding phenomena and factors affecting weld penetration and welding defects

    Science.gov (United States)

    Katayama, Seiji; Kawahito, Yousuke; Mizutani, Masami

    The behavior and effect of a plasma plume on the weld penetration are greatly different between CO2 laser welding and YAG, disk or fiber laser welding. The effects of the power and the power density on the weld penetration are elucidated. Spattering leading to the formation of underfilled weld beads is controlled by inclining the laser beam. Porosity is formed from bubbles generated from the tip of the keyhole at low welding speed or from the middle part of the keyhole at high laser power density. Cracking easily occurs in pulsed spot welding of aluminum alloys.

  9. Robo-line storage: Low latency, high capacity storage systems over geographically distributed networks

    Science.gov (United States)

    Katz, Randy H.; Anderson, Thomas E.; Ousterhout, John K.; Patterson, David A.

    1991-01-01

    Rapid advances in high performance computing are making possible more complete and accurate computer-based modeling of complex physical phenomena, such as weather front interactions, dynamics of chemical reactions, numerical aerodynamic analysis of airframes, and ocean-land-atmosphere interactions. Many of these 'grand challenge' applications are as demanding of the underlying storage system, in terms of their capacity and bandwidth requirements, as they are on the computational power of the processor. A global view of the Earth's ocean chlorophyll and land vegetation requires over 2 terabytes of raw satellite image data. In this paper, we describe our planned research program in high capacity, high bandwidth storage systems. The project has four overall goals. First, we will examine new methods for high capacity storage systems, made possible by low cost, small form factor magnetic and optical tape systems. Second, access to the storage system will be low latency and high bandwidth. To achieve this, we must interleave data transfer at all levels of the storage system, including devices, controllers, servers, and communications links. Latency will be reduced by extensive caching throughout the storage hierarchy. Third, we will provide effective management of a storage hierarchy, extending the techniques already developed for the Log Structured File System. Finally, we will construct a protototype high capacity file server, suitable for use on the National Research and Education Network (NREN). Such research must be a Cornerstone of any coherent program in high performance computing and communications.

  10. Effects of moment of inertia on restricted motion swing speed.

    Science.gov (United States)

    Schorah, David; Choppin, Simon; James, David

    2015-06-01

    In many sports, the maximum swing speed of a racket, club, or bat is a key performance parameter. Previous research in multiple sports supports the hypothesis of an inverse association between the swing speed and moment of inertia of an implement. The aim of this study was to rigorously test and quantify this relationship using a restricted swinging motion. Eight visually identical rods with a common mass but variable moment of inertia were manufactured. Motion capture technology was used to record eight participants' maximal effort swings with the rods. Strict exclusion criteria were applied to data that did not adhere to the prescribed movement pattern. The study found that for all participants, swing speed decreased with respect to moment of inertia according to a power relationship. However, in contrast to previous studies, the rate of decrease varied from participant to participant. With further analysis it was found that participants performed more consistently at the higher end of the moment of inertia range tested. The results support the inverse association between swing speed and moment of inertia but only for higher moment of inertia implements.

  11. Effects of microscale inertia on dynamic ductile crack growth

    Science.gov (United States)

    Jacques, N.; Mercier, S.; Molinari, A.

    2012-04-01

    The aim of this paper is to investigate the role of microscale inertia in dynamic ductile crack growth. A constitutive model for porous solids that accounts for dynamic effects due to void growth is proposed. The model has been implemented in a finite element code and simulations of crack growth in a notched bar and in an edge cracked specimen have been performed. Results are compared to predictions obtained via the Gurson-Tvergaard-Needleman (GTN) model where micro-inertia effects are not accounted for. It is found that microscale inertia has a significant influence on the crack growth. In particular, it is shown that micro-inertia plays an important role during the strain localisation process by impeding void growth. Therefore, the resulting damage accumulation occurs in a more progressive manner. For this reason, simulations based on the proposed modelling exhibit much less mesh sensitivity than those based on the viscoplastic GTN model. Microscale inertia is also found to lead to lower crack speeds. Effects of micro-inertia on fracture toughness are evaluated.

  12. Motion planning for variable inertia mechanical systems

    Science.gov (United States)

    Shammas, Elie A.; Choset, Howie; Rizzi, Alfred A.

    2006-05-01

    In this paper, we generate gaits for mixed systems, that is, dynamic systems that are subject to a set of nonholonomic constraints. What is unique about mixed systems is that when we express their dynamics in body coordinates, the motion of these systems can be attributed to two decoupled terms: the geometric and dynamic phase shifts. In our prior work, we analyzed systems whose dynamic phase shift was null by definition. Purely mechanical and principally kinematic systems are two classes of mechanical systems that have this property. We generated gaits for these two classes of systems by intuitively evaluating their geometric phase shift and relating it to a volume integral under well-defined height functions. One of the contributions of this paper is to present a similar intuitive approach for computing the dynamic phase shift. We achieve this, by introducing a new scaled momentum variable that not only simplifies the momentum evolution equation but also allows us to introduce a new set of well-defined gamma functions which enable us to intuitively evaluate the dynamic phase shift. More specifically, by analyzing these novel gamma functions in a similar way to how we analyzed height functions, and by analyzing the sign-definiteness of the scaled momentum variable, we are able to ensure that the dynamic phase shift is non-zero solely along the desired fiber direction. Finally, we also introduce a novel mechanical system, the variable inertia snakeboard, which is a generalization of the original snakeboard that was previously studied in the literature. Not only does this general system help us identify regions of the base space where we can not define a certain type of gaits, but also it helps us verify the generality and applicability of our gait generation approach.

  13. Tip shift in the zero inertia powertrain

    Energy Technology Data Exchange (ETDEWEB)

    Serrarens, A.F.A.; Vroemen, B.G.; Veldpaus, F.E.; Veenhuizen, P.A.

    2002-07-01

    For any transmission type the vehicle's responsiveness during large and/or fast engine speed shifts may appear reluctant or even counteractive. This is caused by unwanted inertial torques stemming from accelerating or decelerating the rotating elements within the engine and transmission. Reminiscent of comparable behaviour seen in aircraft jet-propulsion, this phenomenon is also referred to as 'jet-start'. To overcome this behaviour, a CVT powertrain is augmented with a powersplitting planetary gear stage and compact steel flywheel. The new transmission-coded zero inertia (ZI) powertrain-seamlessly combines two contradictive features: the driveability in terms of the pedal-to-wheel response is greatly improved and a large leap towards optimal fuel economy can be made. The latter is achieved by cruising the vehicle at extremely low engine speeds owing to the large ratio-coverage of the CVT. As for the driveability, the flywheel acts as a peak shaver. During engine speed shifts it delivers power at (semi-) pedal kick down (downshift) and absorbs kinetic energy of the engine sided powertrain elements at pedal back-out (upshift). In this paper, the behaviour of the ZI system is evaluated in 'tip-shift' mode. In field experiments the tip-shift in a VW Bora test vehicle with ZI powertrain is compared with a commercially available Mini One with CVT. A test panel of 10 people drove the vehicles, executed predefined tasks and evaluated their findings. The results of these experiments are also reported in this paper. (orig.)

  14. Efficiency of the Inertia Friction Welding Process and Its Dependence on Process Parameters (Postprint)

    Science.gov (United States)

    2017-04-28

    W. Li: Adv. Mater. Sci. Eng ., 2013, vol. 2013, pp. 196382(1)–82(9). 8. F.F. Wang, W.Y. Li, J.L. Li, and A. Vairis: Int. J. Adv. Manuf. Technol., 2014...J. Mater. Eng . Perform., 2015, vol. 24, pp. 1173–84. 3342—VOLUME 48A, JULY 2017 METALLURGICAL AND MATERIALS TRANSACTIONS A 15 Distribution A. Approved for public release (PA): distribution unlimited.

  15. 四面体的惯量张量%Rotational Inertia of an Arbitrary Tetrahedron and Inertia Tensor

    Institute of Scientific and Technical Information of China (English)

    刘凤智

    2011-01-01

    The rotational inertia of the rigid plane with symmetry is calculated easily, but the rotational inertia of an arbitrarily tetrahedron without symmetry is calculated difficultly. Using the parallel axis theorem of the rotational inertia,it can be achieved by single integral's method,then gives inertia tensor.%具有对称性的平面刚体,容易求出它的转动惯量.对没有对称性的四面体计算它的转动惯量却比较困难,利用转动惯量的平行轴定理,使用单重积分即可求出了四面体的转动惯量,进而给出惯量张量.

  16. Model of Layered Weld Formation Under Narrow Gap Pulse Welding

    Science.gov (United States)

    Krampit, A. G.

    2016-04-01

    The model parameters of narrow gap pulse welding can be divided into input, internal and output ones. The breadth of gap, that is, clearance breadth between upright edges is one of key parameters securing high quality of a weld joint. The paper presents theoretical outcomes for the model of layered weld formation under narrow gap pulse welding. Based on these studies is developed model of processes, which occur in the weld pool under pulse grove welding. It comprises the scheme of liquid metal motion in the weld pool, scheme of fusion with the side edge and in the bottom part, and the scheme of welding current impulse effect on the structure of a weld joint.

  17. Welding processes handbook

    CERN Document Server

    Weman, Klas

    2003-01-01

    Deals with the main commercially significant and commonly used welding processes. This title takes the student or novice welder through the individual steps involved in each process in an easily understood way. It covers many of the requirements referred to in European Standards including EN719, EN 729, EN 729 and EN 287.$bWelding processes handbook is a concise, explanatory guide to the main commercially significant and commonly-used welding processes. It takes the novice welder or student through the individual steps involved in each process in a clear and easily understood way. It is intended to provide an up-to-date reference to the major applications of welding as they are used in industry. The contents have been arranged so that it can be used as a textbook for European welding courses in accordance with guidelines from the European Welding Federation. Welding processes and equipment necessary for each process are described so that they can be applied to all instruction levels required by the EWF and th...

  18. Application of explosive welding to heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Arthur, G.

    1983-10-01

    The subject is discussed under the headings: advantages of explosive welding; principle of explosive welding; explosive welding of tubes; metallurgy of explosive welds (micrographs; microhardness); tubular heat exchangers; plugging; sleeving; retubing; construction of new heat exchangers; thermal sleeves.

  19. Thermal stir welding apparatus

    Science.gov (United States)

    Ding, R. Jeffrey (Inventor)

    2011-01-01

    A welding method and apparatus are provided for forming a weld joint between first and second elements of a workpiece. The method includes heating the first and second elements to form an interface of material in a plasticized or melted state interface between the elements. The interface material is then allowed to cool to a plasticized state if previously in a melted state. The interface material, while in the plasticized state, is then mixed, for example, using a grinding/extruding process, to remove any dendritic-type weld microstructures introduced into the interface material during the heating process.

  20. Thermal stir welding process

    Science.gov (United States)

    Ding, R. Jeffrey (Inventor)

    2012-01-01

    A welding method is provided for forming a weld joint between first and second elements of a workpiece. The method includes heating the first and second elements to form an interface of material in a plasticized or melted state interface between the elements. The interface material is then allowed to cool to a plasticized state if previously in a melted state. The interface material, while in the plasticized state, is then mixed, for example, using a grinding/extruding process, to remove any dendritic-type weld microstructures introduced into the interface material during the heating process.

  1. Fusion Welding Research.

    Science.gov (United States)

    2014-09-26

    RD-AlSO 253 FUSION WELDING RESEARCH(U) MASSACHUSETTS INST OF TECH L/I CAMBRIDGE DEPT OF MATERIALS SCIENCE AND ENGINEERING T W EAGAR ET AL. 30 RPR 85...NUMBER 12. GOV’ ACCESSION NO. 3. RECICIE-S CATALOG NUMBER 4. T TL V nd Subtitle) S. P OFRPR PERIOD COVERED 5t h A~nnual Technical Report Fusion Welding ...research S on welding processes. Studies include metal vapors in the arc, development of a high speed infrared temperature monitor, digital signal

  2. Review of Welding Terminology

    Directory of Open Access Journals (Sweden)

    Angelika Petrėtienė

    2011-04-01

    Full Text Available The paper discusses welding terms in accordance with the Lithuanian standard LST EN 1792 „Welding. The multilingual list of welding terms and similar processes”, „The Russian–Lithuanian dictionary of the terms of mechanical engineering technology and welding“ and the examples from postgraduates‘ final works. It analyses the infringement of lexical, word-building and morphological rules. First-year students should already be familiar with the standardized terms of their speciality. More active propagation of the terms should help to avoid terminology mistakes in various scientific spheres.

  3. Study on movement inertia in the Earth multi-body system

    Institute of Scientific and Technical Information of China (English)

    CHEN; Xiaofei; BI; Siwen; GONG; Huili

    2006-01-01

    This paper summarizes the first movement and mass centre of stratum-block movement inertia in the Earth multi-body system and introduces its application. It also elaborates the moment of inertia and the products of inertia: the inertia dyadic transformation of reference system and the parallel axis theorem of stratum-block movement inertia of the Earth multi-body system. It provides an academic foundation for research on the dynamic model of Earth multi-body system.

  4. Hybrid laser-arc welding

    DEFF Research Database (Denmark)

    Hybrid laser-arc welding (HLAW) is a combination of laser welding with arc welding that overcomes many of the shortfalls of both processes. This important book gives a comprehensive account of hybrid laser-arc welding technology and applications. The first part of the book reviews...... the characteristics of the process, including the properties of joints produced by hybrid laser-arc welding and ways of assessing weld quality. Part II discusses applications of the process to such metals as magnesium alloys, aluminium and steel as well as the use of hybrid laser-arc welding in such sectors as ship...... building and the automotive industry. With its distinguished editor and international team of contributors, Hybrid laser-arc welding, will be a valuable source of reference for all those using this important welding technology. Professor Flemming Ove Olsen works in the Department of Manufacturing...

  5. Development of a welding system for 3D steel rapid prototyping process

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Metal device rapid prototyping with welding is one of the research interests at present. A controlled inertial droplet transfer MAG welding (CIDTMAGW) process was developed for the 3D steel device rapid prototyping with metal deposition. In this process, by using a special designed wire feeder, a controlled inertia is imposed on the droplet formed on the wire tip and combines with the arc force to make it detached. Thus, according to the requirements of rapid prototyping, the arc heat and the droplet detaching force can be separately controlled to attain a stable and satisfactory metal deposition process. A CIDTMAGW system and a testing manipulator for the 3D steel device rapid prototyping are presented. The required software is completed as well. The experiments proved that the geometric formation of the rapid prototyping device with welding deposition is well agreed the data of the device CAD modeling. The surface of the deposited device is comparatively smooth.

  6. Friction stir welding tool

    Science.gov (United States)

    Tolle; Charles R. , Clark; Denis E. , Barnes; Timothy A.

    2008-04-15

    A friction stir welding tool is described and which includes a shank portion; a shoulder portion which is releasably engageable with the shank portion; and a pin which is releasably engageable with the shoulder portion.

  7. Magnetic Pulse Welding Technology

    Directory of Open Access Journals (Sweden)

    Ahmad K. Jassim

    2011-12-01

    Full Text Available In this paper, the benefits of using Magnetic Pulse machine which is belong to Non-conventional machine instead of conventional machine. Magnetic Pulse Technology is used for joining dissimilar metals, and for forming and cutting metals. It is a non contact technique. Magnetic field is used to generate impact magnetic pressure for welding and forming the work piece by converted the electrical energy to mechanical energy. It is enable us to design previously not possible by welding dissimilar materials and allowing to welds light and stronger materials together. It can be used to weld metallic with non metallic materials to created mechanical lock on ceramics, polymers, rubbers and composites. It is green process; there is no heat, no radiation, no gas, no smoke and sparks, therefore the emissions are negligible.

  8. Explosive Welding with Nitroguanidine.

    Science.gov (United States)

    Sadwin, L D

    1964-03-13

    By using the explosive nitroguanidine, continuous welds can be made between similar and dissimilar metals. Since low detonation pressures are attainable, pressure transfer media are not required between the explosive and the metal surface. The need for either a space or an angle between the metals is eliminated, and very low atmospheric pressures are not required. Successful welds have been made between tantalum and 4140 steel, 3003H14 aluminum and 4140 steel, and 304 stainless steel and 3003H14 aluminum.

  9. Laser Impact Welding

    OpenAIRE

    Daehn, Glenn S.; Lippold, John; Liu, Deijan; Taber, Geoff; Wang, Huimin

    2012-01-01

    Laser impact welding is a solid-state, collision-based welding process. In this process, laser-generated optical energy is converted to kinetic energy through the ablation at the surface and confinement of the gas generated between a flyer and backing plate. The launch of the flyer can be affected by many factors, for example, backing material, ablative layer, and flyer thickness. In this paper, the effect of three backing materials: glass, polycarbonate and cellophane tape, we...

  10. Welding of solid wood

    OpenAIRE

    Ivica Župčić; Goran Mihulja; Andrija Bogner; Ivica Grbac; Ivica @up~i}, Goran Mihulja, Andrija Bogner, Ivica Grbac,; Božidar Hrovat

    2008-01-01

    This paper presents the up-to-date knowledge and results of the application of wood welding techniques at the Faculty of Forestry University of Zagreb. Wood welding technologies have been developed as a new way of bonding timber by using high temperature generatedby friction and pressure. Timber is assembled without any adhesives. During the process the surface layer of timber (lignin), which is in direct contact with its counterpart, melts due to high pressure and temperature, which is usual...

  11. High capacity image steganography method based on framelet and compressive sensing

    Science.gov (United States)

    Xiao, Moyan; He, Zhibiao

    2015-12-01

    To improve the capacity and imperceptibility of image steganography, a novel high capacity and imperceptibility image steganography method based on a combination of framelet and compressive sensing (CS) is put forward. Firstly, SVD (Singular Value Decomposition) transform to measurement values obtained by compressive sensing technique to the secret data. Then the singular values in turn embed into the low frequency coarse subbands of framelet transform to the blocks of the cover image which is divided into non-overlapping blocks. Finally, use inverse framelet transforms and combine to obtain the stego image. The experimental results show that the proposed steganography method has a good performance in hiding capacity, security and imperceptibility.

  12. Development and Testing of a High Capacity Plasma Chemical Reactor in the Ukraine

    Energy Technology Data Exchange (ETDEWEB)

    Reilly, Raymond W.

    2012-07-30

    This project, Development and Testing of a High Capacity Plasma Chemical Reactor in the Ukraine was established at the Kharkiv Institute of Physics and Technology (KIPT). The associated CRADA was established with Campbell Applied Physics (CAP) located in El Dorado Hills, California. This project extends an earlier project involving both CAP and KIPT conducted under a separate CRADA. The initial project developed the basic Plasma Chemical Reactor (PCR) for generation of ozone gas. This project built upon the technology developed in the first project, greatly enhancing the output of the PCR while also improving reliability and system control.

  13. Nuclear inertia from the time dependent pairing equations

    Science.gov (United States)

    Mirea, M.

    2016-10-01

    In a dynamical system, the momenta of inertia and the effective masses are not adiabatic quantities, but are dynamical ones that depend on the dissipated energy accumulated during motion. However, these parameters are calculated for adiabatic nuclear systems, leaving no room for dissipated energy. In this work, a formalism is elaborated in order to derive simultaneously the nuclear momenta of inertia and the effective masses by taking into account the appearance of dissipated energy for large amplitude motion of the nuclear system. The expressions that define the inertia are obtained from the variational principle. The same principle manages the time dependent pairing equations, offering estimations of the averaged dissipation energy for large amplitude motions. The model is applied to 232Th fission. The fission barrier was calculated along the least action trajectory. The dissipation energy, effective mass and moment of inertia are determined for different values of the collective velocities. The dissipation increases with the internuclear velocity in binary disintegration processes and modifies the effective mass parameters. We observed that the inertia decreases as long as the collective velocity increases to some moderate values and begins to grow for larger collective velocities. So, a dependence between the cranking mass parameters and the intrinsic excitation energy is evidenced. In order to investigate the overall effect, the half-lives are predicted for adiabatic and dynamics simulations.

  14. Nuclear constraints on the momenta of inertia of neutron stars

    CERN Document Server

    Worley, Aaron; Li, Bao-An

    2008-01-01

    Properties and structure of neutron stars are determined by the equation of state of stellar matter. Recent data on isospin-diffusion and isoscaling in heavy-ion collisions at intermediate energies as well as the size of neutron skin in $^{208}Pb$ have constrained considerably the density dependence of the nuclear symmetry energy and, in turn, the equation of state of neutron-rich nucleonic matter. These constraints could provide more reliable information about the neutron star moment of inertia. The moment of inertia of component A of the extremely relativistic double neutron star system PSR J0737-3039 will be measurable in the near future and this makes theoretical calculations of the moment of inertia very timely. We show that the moment of inertia of PSR J0737-3039A is between 1.30 and 1.63 $(\\times10^{45}g$ $cm^2)$. The moment of inertia increases with rotational frequency at a rate strongly dependent upon the equation of state. Finally, we demonstrate that the transition density at the crust-core bounda...

  15. Empirical moments of inertia of axially asymmetric nuclei

    Science.gov (United States)

    Allmond, J. M.; Wood, J. L.

    2017-04-01

    Empirical moments of inertia, J1, J2, J3, of atomic nuclei with E (41+) / E (21+) > 2.7 are extracted from experimental 2g,γ+ energies and electric quadrupole matrix elements, determined from multi-step Coulomb excitation data, and the results are compared to expectations based on rigid and irrotational inertial flow. Only by having the signs of the E2 matrix elements, i.e., and , can a unique solution to all three components of the inertia tensor of an asymmetric top be obtained. While the absolute moments of inertia fall between the rigid and irrotational values as expected, the relative moments of inertia appear to be qualitatively consistent with the β2sin2 ⁡ (γ) dependence of the Bohr Hamiltonian which originates from a SO(5) invariance. A better understanding of inertial flow is central to improving collective models, particularly hydrodynamic-based collective models. The results suggest that a better description of collective dynamics and inertial flow for atomic nuclei is needed. The inclusion of vorticity degrees of freedom may provide a path forward. This is the first report of empirical moments of inertia for all three axes and the results should challenge both collective and microscopic descriptions of inertial flow.

  16. High capacity embedding with indexed data recovery using adjunctive numerical relations in multimedia signal covers

    Science.gov (United States)

    Collins, James C.; Agaian, Sos S.

    2013-05-01

    We introduce a technique for covertly embedding data throughout an audio file using redundant number system decomposition across non-standard digital bit-lines. This bit-line implementation integrates an index recoverable embedded algorithm with an extended bit level representation that achieves a high capacity data channel within an audio multimedia file. It will be shown this new steganography method has minimal aural distortive affects while preserving both first and second order cover statistics, making it less susceptible to most steganalysis attacks. Our research approach involves reviewing the common numerical methods used in common binary-based algorithms. We then describe basic concepts and challenges when attempting to implement complex embedding algorithms that are based on redundant number systems. Finally, we introduce a novel class of numerical based multiple bit-line decomposition systems, which we define as Adjunctive Numerical Representations. The system is primarily described using basic PCM techniques in uncompressed audio files however extended applications for alternate multimedia is addressed. This new embedding system will not only provide the statistical stability required for effective steganography but will also give us an improvement in the embedding capacity in this class of multimedia carrier files. This novelty of our approach is demonstrated by an ability to embed high capacity covert data while simultaneously providing a means for rapid, indexed data recovery.

  17. Charge Modulation in Graphitic Carbon Nitride as a Switchable Approach to High-Capacity Hydrogen Storage.

    Science.gov (United States)

    Tan, Xin; Kou, Liangzhi; Tahini, Hassan A; Smith, Sean C

    2015-11-01

    Electrical charging of graphitic carbon nitride nanosheets (g-C4 N3 and g-C3 N4 ) is proposed as a strategy for high-capacity and electrocatalytically switchable hydrogen storage. Using first-principle calculations, we found that the adsorption energy of H2 molecules on graphitic carbon nitride nanosheets is dramatically enhanced by injecting extra electrons into the adsorbent. At full hydrogen coverage, the negatively charged graphitic carbon nitride achieves storage capacities up to 6-7 wt %. In contrast to other hydrogen storage approaches, the storage/release occurs spontaneously once extra electrons are introduced or removed, and these processes can be simply controlled by switching on/off the charging voltage. Therefore, this approach promises both facile reversibility and tunable kinetics without the need of specific catalysts. Importantly, g-C4 N3 has good electrical conductivity and high electron mobility, which can be a very good candidate for electron injection/release. These predictions may prove to be instrumental in searching for a new class of high-capacity hydrogen storage materials.

  18. Programmatic status of NASA's CSTI high capacity power Stirling space power converter program

    Science.gov (United States)

    Dudenhoefer, James E.

    1990-01-01

    An overview is presented of the NASA Lewis Research Center Free-Piston Stirling Space Power Converter Technology Development Program. This work is being conducted under NASA's Civil Space Technology Initiative (CSTI). The goal of the CSTI High Capacity Power element is to develop the technology base needed to meet the long duration, high capacity power requirements for future NASA space initiatives. Efforts are focused upon increasing system thermal and electric energy conversion efficiency at least fivefold over current SP-100 technology, and on achieving systems that are compatible with space nuclear reactors. The status of test activities with the Space Power Research Engine (SPRE) is discussed. Design deficiencies are gradually being corrected and the power converter is now outputting 11.5 kWe at a temperature ratio of 2 (design output is 12.5 kWe). Detail designs were completed for the 1050 K Component Test Power Converter (CTPC). The success of these and future designs is dependent upon supporting research and technology efforts including heat pipes, gas bearings, superalloy joining technologies and high efficiency alternators. An update of progress in these technologies is provided.

  19. E- and W-band high-capacity hybrid fiber-wireless link

    DEFF Research Database (Denmark)

    Vegas Olmos, Juan José; Pang, Xiaodan; Tafur Monroy, Idelfonso

    2014-01-01

    In this paper we summarize the work conducted in our group in the area of E- and W-band optical high-capacity fiber-wireless links. We present performance evaluations of E- and W-band mm-wave signal generation using photonic frequency upconversion employing both VCSELs and ECLs, along with transm......In this paper we summarize the work conducted in our group in the area of E- and W-band optical high-capacity fiber-wireless links. We present performance evaluations of E- and W-band mm-wave signal generation using photonic frequency upconversion employing both VCSELs and ECLs, along...... with transmission over different type of optical fibers and for a number of values for the wireless link distance. Hybrid wireless-optical links can be composed of mature and resilient technology available off-the-shelf, and provide functionalities that can add value to optical access networks, specifically...... in mobile backhaul/fronthaul applications, dense distributed antenna systems and fiber-over-radio scenarios....

  20. Review on anionic redox for high-capacity lithium- and sodium-ion batteries

    Science.gov (United States)

    Zhao, Chenglong; Wang, Qidi; Lu, Yaxiang; Hu, Yong-Sheng; Li, Baohua; Chen, Liquan

    2017-05-01

    Rechargeable batteries, especially lithium-ion batteries, are now widely used as power sources for portable electronics and electric vehicles, but material innovations are still needed to satisfy the increasing demand for larger energy density. Recently, lithium- and sodium-rich electrode materials, including the A2MO3-family layered compounds (A  =  Li, Na; M  =  Mn4+, Ru4+, etc), have been extensively studied as potential high-capacity electrode materials for a cumulative cationic and anionic redox activity. Negatively charged oxide ions can potentially donate electrons to compensate for the absence of oxidable transition metals as a redox center to further increase the reversible capacity. Understanding and controlling the state-of-the-art anionic redox processes is pivotal for the design of advanced energy materials, highlighted in rechargeable batteries. Hence, experimental and theoretical approaches have been developed to consecutively study the diverting processes, states, and structures involved. In this review, we attempt to present a literature overview and provide insight into the reaction mechanism with respect to the anionic redox processes, proposing some opinions as target oriented. It is hoped that, through this discussion, the search for anionic redox electrode materials with high-capacity rechargeable batteries can be advanced, and practical applications realized as soon as possible.

  1. High capacity fiber optic sensor networks using hybrid multiplexing techniques and their applications

    Science.gov (United States)

    Sun, Qizhen; Li, Xiaolei; Zhang, Manliang; Liu, Qi; Liu, Hai; Liu, Deming

    2013-12-01

    Fiber optic sensor network is the development trend of fiber senor technologies and industries. In this paper, I will discuss recent research progress on high capacity fiber sensor networks with hybrid multiplexing techniques and their applications in the fields of security monitoring, environment monitoring, Smart eHome, etc. Firstly, I will present the architecture of hybrid multiplexing sensor passive optical network (HSPON), and the key technologies for integrated access and intelligent management of massive fiber sensor units. Two typical hybrid WDM/TDM fiber sensor networks for perimeter intrusion monitor and cultural relics security are introduced. Secondly, we propose the concept of "Microstructure-Optical X Domin Refecltor (M-OXDR)" for fiber sensor network expansion. By fabricating smart micro-structures with the ability of multidimensional encoded and low insertion loss along the fiber, the fiber sensor network of simple structure and huge capacity more than one thousand could be achieved. Assisted by the WDM/TDM and WDM/FDM decoding methods respectively, we built the verification systems for long-haul and real-time temperature sensing. Finally, I will show the high capacity and flexible fiber sensor network with IPv6 protocol based hybrid fiber/wireless access. By developing the fiber optic sensor with embedded IPv6 protocol conversion module and IPv6 router, huge amounts of fiber optic sensor nodes can be uniquely addressed. Meanwhile, various sensing information could be integrated and accessed to the Next Generation Internet.

  2. Crack-resistant polyimide coating for high-capacity battery anodes

    Science.gov (United States)

    Li, Yingshun; Wang, Shuo; Lee, Pui-Kit; He, Jieqing; Yu, Denis Y. W.

    2017-10-01

    Electrode cracking is a serious problem that hinders the application of many next-generation high-capacity anode materials for lithium-ion batteries. Even though nano-sizing the material can reduce fracturing of individual particles, capacity fading is still observed due to large volume change and loss of contact in the electrode during lithium insertion and extraction. In this study, we design a crack-resistant high-modulus polyimide coating with high compressive strength which can hold multiple particles together during charge and discharge to maintain contact. The effectiveness of the coating is demonstrated on tin dioxide, a high-capacity large-volume-change material that undergoes both alloy and conversion reactions. The polyimide coating improves capacity retention of SnO2 from 80% to 100% after 80 cycles at 250 mA g-1. Stable capacity of 585 mAh g-1 can be obtained even at 500 mA g-1 after 300 cycles. Scanning electron microscopy and in-situ dilatometry confirm that electrode cracking is suppressed and thickness change is reduced with the coating. In addition, the chemically-stable polyimide film can separate the surface from direct contact with electrolyte, improving coulombic efficiency to ∼100%. We expect the novel strategy of suppressing electrode degradation with a crack-resistant coating can also be used for other alloy and conversion-based anodes.

  3. Certification of a weld produced by friction stir welding

    Science.gov (United States)

    Obaditch, Chris; Grant, Glenn J

    2013-10-01

    Methods, devices, and systems for providing certification of friction stir welds are disclosed. A sensor is used to collect information related to a friction stir weld. Data from the sensor is compared to threshold values provided by an extrinsic standard setting organizations using a certification engine. The certification engine subsequently produces a report on the certification status of the weld.

  4. Gravitation and inertia; a rearrangement of vacuum in gravity

    CERN Document Server

    Ter-Kazarian, Gagik

    2010-01-01

    We address the gravitation and inertia in the framework of 'general gauge principle', which accounts for 'gravitation gauge group' generated by hidden local internal symmetry implemented on the flat space. We connect this group to nonlinear realization of the Lie group of 'distortion' of local internal properties of six-dimensional flat space, which is assumed as a toy model underlying four-dimensional Minkowski space. The agreement between proposed gravitational theory and available observational verifications is satisfactory. We construct relativistic field theory of inertia and derive the relativistic law of inertia. This theory furnishes justification for introduction of the Principle of Equivalence. We address the rearrangement of vacuum state in gravity resulting from these ideas.

  5. Gender in Science and Engineering Faculties: Demographic Inertia Revisited.

    Directory of Open Access Journals (Sweden)

    Nicole R Thomas

    Full Text Available The under-representation of women on faculties of science and engineering is ascribed in part to demographic inertia, which is the lag between retirement of current faculty and future hires. The assumption of demographic inertia implies that, given enough time, gender parity will be achieved. We examine that assumption via a semi-Markov model to predict the future faculty, with simulations that predict the convergence demographic state. Our model shows that existing practices that produce gender gaps in recruitment, retention, and career progression preclude eventual gender parity. Further, we examine sensitivity of the convergence state to current gender gaps to show that all sources of disparity across the entire faculty career must be erased to produce parity: we cannot blame demographic inertia.

  6. Gender in Science and Engineering Faculties: Demographic Inertia Revisited.

    Science.gov (United States)

    Thomas, Nicole R; Poole, Daniel J; Herbers, Joan M

    2015-01-01

    The under-representation of women on faculties of science and engineering is ascribed in part to demographic inertia, which is the lag between retirement of current faculty and future hires. The assumption of demographic inertia implies that, given enough time, gender parity will be achieved. We examine that assumption via a semi-Markov model to predict the future faculty, with simulations that predict the convergence demographic state. Our model shows that existing practices that produce gender gaps in recruitment, retention, and career progression preclude eventual gender parity. Further, we examine sensitivity of the convergence state to current gender gaps to show that all sources of disparity across the entire faculty career must be erased to produce parity: we cannot blame demographic inertia.

  7. Factors associated with clinical inertia: an integrative review

    Science.gov (United States)

    Aujoulat, Isabelle; Jacquemin, Patricia; Rietzschel, Ernst; Scheen, André; Tréfois, Patrick; Wens, Johan; Darras, Elisabeth; Hermans, Michel P

    2014-01-01

    Failure to initiate or intensify therapy according to evidence-based guidelines is increasingly being acknowledged as a phenomenon that contributes to inadequate management of chronic conditions, and is referred to as clinical inertia. However, the number and complexity of factors associated with the clinical reasoning that underlies the decision-making processes in medicine calls for a critical examination of the consistency of the concept. Indeed, in the absence of information on and justification of treatment decisions that were made, clinical inertia may be only apparent, and actually reflect good clinical practice. This integrative review seeks to address the factors generally associated with clinical inaction, in order to better delineate the concept of true clinical inertia. PMID:24868181

  8. The calculation of robot dynamics using articulated-body inertias

    Science.gov (United States)

    Featherstone, R.

    1983-05-01

    This paper describes a new method for calculating the acceleration of a robot in response to given actuator forces. The method is applicable to open-loop kinematic chains containing revolute and prismatic joints. The algorithm is based on recursive formulas involving quantities called articulated-body inertias, which represent the inertia properties of collections of rigid bodies connected together by joints allowing constrained relative motion between the bodies. A new, matrix-based notation is introduced to represent articulated-body inertias and other spatial quantities. This notation is used to develop the algorithm, and results in a compact representation of the equations. The new algorithm has a computational requirement that varies linearly with the number of joints, and its efficiency is compared with other published algorithms.

  9. Exact Computation of Parallel Robot's Generalized Inertia Matrix

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yongjie; YANG Zhiyong; MEI Jiangping; HUANG Tian

    2005-01-01

    According to the definition of the new hypothetical states which have obvious physical significance and are termed as no-gravity static and accelerated states, a method for exact computation of the parallel robot's generalized inertia matrix is presented. Based on the matrix theory, the generalized inertia matrix of the parallel robot can be computed on the assumption that the robot is in these new hypothetical states respectively. The approach is demonstrated by the Delta robot as an example. Based on the principle of the virtual work, the inverse dynamics model of the robot is formulized after the kinematics analysis. Finally, a numerical example is given and the element distribution of the Delta robot's inertia matrix in the workspace is studied. The method has computational advantage of numerical accuracy for the Delta robot and can be parallelized easily.

  10. Self-Reacting Friction Stir Welding for Aluminum Alloy Circumferential Weld Applications

    Science.gov (United States)

    Bjorkman, Gerry; Cantrell, Mark; Carter, Robert

    2003-01-01

    Friction stir welding is an innovative weld process that continues to grow in use, in the commercial, defense, and space sectors. It produces high quality and high strength welds in aluminum alloys. The process consists of a rotating weld pin tool that plasticizes material through friction. The plasticized material is welded by applying a high weld forge force through the weld pin tool against the material during pin tool rotation. The high weld forge force is reacted against an anvil and a stout tool structure. A variation of friction stir welding currently being evaluated is self-reacting friction stir welding. Self-reacting friction stir welding incorporates two opposing shoulders on the crown and root sides of the weld joint. In self-reacting friction stir welding, the weld forge force is reacted against the crown shoulder portion of the weld pin tool by the root shoulder. This eliminates the need for a stout tooling structure to react the high weld forge force required in the typical friction stir weld process. Therefore, the self-reacting feature reduces tooling requirements and, therefore, process implementation costs. This makes the process attractive for aluminum alloy circumferential weld applications. To evaluate the application of self-reacting friction stir welding for aluminum alloy circumferential welding, a feasibility study was performed. The study consisted of performing a fourteen-foot diameter aluminum alloy circumferential demonstration weld using typical fusion weld tooling. To accomplish the demonstration weld, weld and tack weld development were performed and fourteen-foot diameter rings were fabricated. Weld development consisted of weld pin tool selection and the generation of a process map and envelope. Tack weld development evaluated gas tungsten arc welding and friction stir welding for tack welding rings together for circumferential welding. As a result of the study, a successful circumferential demonstration weld was produced leading

  11. Welding defects at friction stir welding

    Directory of Open Access Journals (Sweden)

    P. Podržaj

    2015-04-01

    Full Text Available The paper presents an overview of different types of defects at friction stir welding. In order to explain the reasons for their occurrence a short theoretical background of the process is given first. The main emphasis is on the parameters that influence the process. An energy supply based division of defects into three disjoint groups was used. The occurring defects are demonstrated on various materials.

  12. The Earth's Equilibrium Climate Sensitivity and Thermal Inertia

    CERN Document Server

    Royce, B S H

    2013-01-01

    The Earth's equilibrium climate sensitivity has received much attention because of its relevance and importance for global warming policymaking. This paper focuses on the Earth's \\emph{thermal inertia time scale} which has received relatively little attention. The difference between the observed transient climate sensitivity and the equilibrium climate sensitivity is shown to be proportional to the thermal inertia time scale, and the numerical value of the proportionality factor is determined using recent observational data. Many useful policymaking insights can be extracted from the resulting empirical quantitative relation.

  13. Sleep Inertia: Is There a Worst Time to Wake Up?

    Science.gov (United States)

    1992-07-07

    deprivation without naps we almost never have had a subject withdraw. Perhaps, long-term training in taking many short naps or polyphasic sleep to replace...AD-A256 602 HhIllllM 111lUIIHflllhE’l’• II SLEEP INERTIA: IS THERE A WORST TIME TO WAKE UP? DTIC Aa ELECTE OCT 2 81992 T. Kelly --A 11. akoff 92...BETHESDA. MARYLAND SLEEP INERTIA: IS THERE A WORST TIME TO WAKE-UP? Paul Naitoh*, Tamsin Kelly* and Harvey Babkoff** *Naval Health Research Center P.O

  14. Welding. Performance Objectives. Intermediate Course.

    Science.gov (United States)

    Vincent, Kenneth

    Several intermediate performance objectives and corresponding criterion measures are listed for each of nine terminal objectives for an intermediate welding course. The materials were developed for a 36-week (3 hours daily) course designed to prepare the student for employment in the field of welding. Electric welding and specialized (TIG & MIG)…

  15. Welding. Performance Objectives. Basic Course.

    Science.gov (United States)

    Vincent, Kenneth

    Several intermediate performance objectives and corresponding criterion measures are listed for each of eight terminal objectives for a basic welding course. The materials were developed for a 36-week (2 hours daily) course developed to teach the fundamentals of welding shop work, to become familiar with the operation of the welding shop…

  16. ON INTELLIGENTIZED TECHNOLOGIES FOR MODERN WELDING MANUFACTURING

    Institute of Scientific and Technical Information of China (English)

    Chen Shanben; Qiu Tao; Lin Tao; Wu Yixiong

    2003-01-01

    A short survey on researching and developing status of intelligent technologies in modem welding manufacturing is given. According to the developing trend of advanced manufacturing technology, a concept on intelligentized welding manufacturing engineering (IWME), is presented for systematization of researching and developing domains on welding automation, intelligentized welding,robotic and flexible welding and advanced welding manufacturing technologies. And key technologies of welding intelligent manufacturing and its developing trend in the future are investigated.

  17. Friction stir welding tool and process for welding dissimilar materials

    Science.gov (United States)

    Hovanski, Yuri; Grant, Glenn J; Jana, Saumyadeep; Mattlin, Karl F

    2013-05-07

    A friction stir welding tool and process for lap welding dissimilar materials are detailed. The invention includes a cutter scribe that penetrates and extrudes a first material of a lap weld stack to a preselected depth and further cuts a second material to provide a beneficial geometry defined by a plurality of mechanically interlocking features. The tool backfills the interlocking features generating a lap weld across the length of the interface between the dissimilar materials that enhances the shear strength of the lap weld.

  18. Weld Nugget Temperature Control in Thermal Stir Welding

    Science.gov (United States)

    Ding, R. Jeffrey (Inventor)

    2014-01-01

    A control system for a thermal stir welding system is provided. The control system includes a sensor and a controller. The sensor is coupled to the welding system's containment plate assembly and generates signals indicative of temperature of a region adjacent and parallel to the welding system's stir rod. The controller is coupled to the sensor and generates at least one control signal using the sensor signals indicative of temperature. The controller is also coupled to the welding system such that at least one of rotational speed of the stir rod, heat supplied by the welding system's induction heater, and feed speed of the welding system's weld material feeder are controlled based on the control signal(s).

  19. Weld pool image sensor for pulsed MIG welding

    Institute of Scientific and Technical Information of China (English)

    Liu Pengfei; Sun Zhenguo; Huang Cao; Chen Qiang

    2008-01-01

    Visual image sensor is developed to detect the weld pool images in pulsed MIG welding. An exposure controller, which is composed of the modules of the voltage transforming, the exposure parameters presetting, the complex programmable logic device (CPLD) based logic controlling, exposure signal processing, the arc state detecting, the mechanical iris driving and so on, is designed at first. Then, a visual image sensor consists of an ordinary CCD camera, optical system and exposure controller is established. The exposure synchronic control logic is described with very-high-speed integrated circuit hardware description language (VHDL) and programmed with CPLD, to detect weld pool images at the stage of base current in pulsed MIG welding. Finally, both bead on plate welding and V groove filled welding are carried out, clear and consistent weld pool images are acquired.

  20. A micro-structured Si-based electrodes for high capacity electrical double layer capacitors

    Science.gov (United States)

    Krikscikas, Valdas; Oguchi, Hiroyuki; Yanazawa, Hiroshi; Hara, Motoaki; Kuwano, Hiroki

    2014-11-01

    We challenged to make basis for Si electrodes of electric double layer capacitors (EDLC) used as a power source of micro-sensor nodes. Mcroelectromechanical systems (MEMS) processes were successfully introduced to fabricate micro-structured Si-based electrodes to obtain high surface area which leads to high capacity of EDLCs. Study of fundamental properties revealed that the microstructured electrodes benefit from good wettability to electrolytes, but suffer from electric resistance. We found that this problem can be solved by metal-coating of the electrode surface. Finally we build an EDLC consisting of Au-coated micro-structured Si electrodes. This EDLC showed capacity of 14.3 mF/cm2, which is about 530 times larger than that of an EDLC consisting of flat Au electrodes.

  1. Synthesization of high-capacity auto-associative memories using complex-valued neural networks

    Science.gov (United States)

    Huang, Yu-Jiao; Wang, Xiao-Yan; Long, Hai-Xia; Yang, Xu-Hua

    2016-12-01

    In this paper, a novel design procedure is proposed for synthesizing high-capacity auto-associative memories based on complex-valued neural networks with real-imaginary-type activation functions and constant delays. Stability criteria dependent on external inputs of neural networks are derived. The designed networks can retrieve the stored patterns by external inputs rather than initial conditions. The derivation can memorize the desired patterns with lower-dimensional neural networks than real-valued neural networks, and eliminate spurious equilibria of complex-valued neural networks. One numerical example is provided to show the effectiveness and superiority of the presented results. Project supported by the National Natural Science Foundation of China (Grant Nos. 61503338, 61573316, 61374152, and 11302195) and the Natural Science Foundation of Zhejiang Province, China (Grant No. LQ15F030005).

  2. Hierarchical network architectures of carbon fiber paper supported cobalt oxide nanonet for high-capacity pseudocapacitors.

    Science.gov (United States)

    Yang, Lei; Cheng, Shuang; Ding, Yong; Zhu, Xingbao; Wang, Zhong Lin; Liu, Meilin

    2012-01-11

    We present a high-capacity pseudocapacitor based on a hierarchical network architecture consisting of Co(3)O(4) nanowire network (nanonet) coated on a carbon fiber paper. With this tailored architecture, the electrode shows ideal capacitive behavior (rectangular shape of cyclic voltammograms) and large specific capacitance (1124 F/g) at high charge/discharge rate (25.34 A/g), still retaining ~94% of the capacitance at a much lower rate of 0.25 A/g. The much-improved capacity, rate capability, and cycling stability may be attributed to the unique hierarchical network structures, which improves electron/ion transport, enhances the kinetics of redox reactions, and facilitates facile stress relaxation during cycling.

  3. Mono-layer BC2 a high capacity anode material for Li-ion batteries

    Science.gov (United States)

    Hardikar, Rahul; Samanta, Atanu; Han, Sang Soo; Lee, Kwang-Ryeol; Singh, Abhishek

    2015-04-01

    Mono-layer of graphene with high surface area compared to the bulk graphite phase, shows less Li uptake. The Li activity or kinetics can be modified via defects and/or substitutional doping. Boron and Nitrogen are the best known dopants for carbonaceous anode materials. In particular, boron doped graphene shows higher capacity and better Li adsorption compared to Nitrogen doped graphene. Here, using first principles density functional theory calculations, we study the spectrum of boron carbide (BCx) mono-layer phases in order to estimate the maximum gravimetric capacity that can be achieved by substitutional doping in graphene. Our results show that uniformly boron doped BC2 phase shows a high capacity of? 1400 mAh/g, much higher than previously reported capacity of BC3. Supported by Korea Institute of Science and Technology.

  4. High-Capacity Hybrid Optical Fiber-Wireless Communications Links in Access Networks

    DEFF Research Database (Denmark)

    Pang, Xiaodan

    techniques with both coherent and incoherent optical sources are studied and demonstrated. Employments of advanced modulation formats including phase-shift keying (PSK), M-quadrature amplitude modulation (QAM) and orthogonal frequency-division multiplexing (OFDM) for high speed photonic-wireless transmission......Integration between fiber-optic and wireless communications systems in the "last mile" access networks is currently considered as a promising solution for both service providers and users, in terms of minimizing deployment cost, shortening upgrading period and increasing mobility and flexibility...... techniques. In conclusion, the results presented in the thesis show the feasibility of employing mm-wave signals, advanced modulation formats and spatial multiplexing technologies in next generation high capacity hybrid optical fiber-wireless access systems....

  5. High-capacity thick cathode with a porous aluminum current collector for lithium secondary batteries

    Science.gov (United States)

    Abe, Hidetoshi; Kubota, Masaaki; Nemoto, Miyu; Masuda, Yosuke; Tanaka, Yuichi; Munakata, Hirokazu; Kanamura, Kiyoshi

    2016-12-01

    A high-capacity thick cathode has been studied as one of ways to improve the energy density of lithium secondary batteries. In this study, the LiFePO4 cathode with a capacity per unit area of 8.4 m Ah cm-2 corresponding to four times the capacity of conventional cathodes has been developed using a three-dimensional porous aluminum current collector called "FUSPOROUS". This unique current collector enables the smooth transfer of electrons and Li+-ions through the thick cathode, resulting in a good rate capability (discharge capacity ratio of 1.0 C/0.2 C = 0.980) and a high charge-discharge cycle performance (80% of the initial capacity at 2000th cycle) even though the electrode thickness is 400 μm. To take practical advantage of the developed thick cathode, conceptual designs for a 10-Ah class cell were also carried out using graphite and lithium-metal anodes.

  6. A high capacity multiple watermarking scheme based on Fourier descriptor and Sudoku

    Science.gov (United States)

    Zhang, Li; Zheng, Huimin

    2015-12-01

    Digital watermark is a type of technology to hide some significant information which is mainly used to protect digital data. A high capacity multiple watermarking method is proposed, which adapts the Fourier descriptor to pre-process the watermarks, while a Sudoku puzzle is used as a reference matrix in embedding process and a key in extraction process. It can dramatically reduce the required capacity by applying Fourier descriptor. Meanwhile, the security of watermarks can be guaranteed due to the Sudoku puzzle. Unlike previous algorithms applying Sudoku puzzle in spatial domain, the proposed algorithm works in transformed domain by applying LWT2.In addition, the proposed algorithm can detect the temper location accurately. The experimental results demonstrated that the goals mentioned above have been achieved.

  7. OTDM Networking for Short Range High-Capacity Highly Dynamic Networks

    DEFF Research Database (Denmark)

    Medhin, Ashenafi Kiros

    This PhD thesis aims at investigating the possibility of designing energy-efficient high-capacity (up to Tbit/s) optical network scenarios, leveraging on the effect of collective switching of many bits simultaneously, as is inherent in high bit rate serial optical data signals. The focus...... is on short range highly dynamic networks, catering to data center needs. The investigation concerns optical network scenarios, and experimental implementations of high bit rate serial data packet generation and reception, scalable optical packet labeling, simple optical label extraction and stable ultra......-fast optical packet switching, with the constraint that there must be potential energy savings, which is also evaluated. A survey of the current trends in data centers is given and state-of-the-art research approaches are mentioned. Optical time-division multiplexing is proposed and demonstrated to generate...

  8. A new method for high-capacity information hiding in video robust against temporal desynchronization

    Science.gov (United States)

    Mitekin, Vitaly; Fedoseev, Victor A.

    2015-02-01

    This paper presents a new method for high-capacity information hiding in digital video and algorithms of embedding and extraction of hidden information based on this method. These algorithms do not require temporal synchronization to provide robustness against both malicious and non-malicious frame dropping (temporal desynchronization). At the same time, due to randomized distribution of hidden information bits across the video frames, the proposed method allows to increase the hiding capacity proportionally to the number of frames used for information embedding. The proposed method is also robust against "watermark estimation" attack aimed at estimation of hidden information without knowing the embedding key or non-watermarked video. Presented experimental results demonstrate declared features of this method.

  9. Lamprey parasitism of sharks and teleosts: high capacity urea excretion in an extant vertebrate relic.

    Science.gov (United States)

    Wilkie, Michael P; Turnbull, Steven; Bird, Jonathan; Wang, Yuxiang S; Claude, Jaime F; Youson, John H

    2004-08-01

    We observed 10 sea lampreys (Petromyzon marinus) parasitizing basking sharks (Cetorhinus maximus), the world's second largest fish, in the Bay of Fundy. Due to the high concentrations of urea in the blood and tissues of ureosmotic elasmobranchs, we hypothesized that sea lampreys would have mechanisms to eliminate co-ingested urea while feeding on basking sharks. Post-removal urea excretion rates (J(Urea)) in two lampreys, removed from separate sharks by divers, were initially 450 ( approximately 9000 micromol N kg-1 h-1) and 75 times ( approximately 1500 micromol N kg-1 h-1) greater than basal (non-feeding) rates ( approximately 20 micromol N kg-1 h-1). In contrast, J(Urea) increased by 15-fold after parasitic lampreys were removed from non-ureosmotic rainbow trout (Oncorhynchus mykiss). Since activities of the ornithine urea cycle (OUC) enzymes, carbamoyl phosphate synthetase III (CPSase III) and ornithine carbamoyl transferase (OCT) were relatively low in liver and below detection in intestine and muscle, it is unlikely that the excreted urea arose from de novo urea synthesis. Measurements of arginase activity suggested that hydrolysis of dietary arginine made a minor contribution to J(Urea.). Post-feeding ammonia excretion rates (J(Amm)) were 15- to 25-fold greater than basal rates in lampreys removed from both basking sharks and rainbow trout, suggesting that parasitic lampreys have a high capacity to deaminate amino acids. We conclude that the sea lamprey's ability to penetrate the dermal denticle armor of sharks, to rapidly excrete large volumes of urea and a high capacity to deaminate amino acids, represent adaptations that have contributed to the evolutionary success of these phylogenetically ancient vertebrates.

  10. High capacity implantable data recorders: system design and experience in canines and Denning black bears.

    Science.gov (United States)

    Laske, Timothy G; Harlow, Henry J; Werder, Jon C; Marshall, Mark T; Iaizzo, Paul A

    2005-11-01

    Implantable medical devices have increasingly large capacities for storing patient data as a diagnostic aid and to allow patient monitoring. Although these devices can store a significant amount of data, an increased ability for data storage was required for chronic monitoring in recent physiological studies. Novel high capacity implantable data recorders were designed for use in advanced physiological studies of canines and free-ranging black bears. These hermitically sealed titanium encased recorders were chronically implanted and programmed to record intrabody broadband electrical activity to monitor electrocardiograms and electromyograms, and single-axis acceleration to document relative activities. Changes in cardiac T-wave morphology were characterized in the canines over a 6 month period, providing new physiological data for the design of algorithms and filtering schemes that could be employed to avoid inappropriate implantable defibrillator shocks. Unique characteristics of bear hibernation physiology were successfully identified in the black bears, including: heart rate, respiratory rate, gross body movement, and shiver An unanticipated high rejection rate of these devices occurred in the bears, with five of six being externalized during the overwintering period, including two devices implanted in the peritoneal cavity. High capacity implantable data recorders were designed and utilized for the collection of long-term physiological data in both laboratory and extreme field environments. The devices described were programmable to accommodate the diverse research protocols. Additionally, we have described substantial differences in the response of two species to a common device. Variations in the foreign body response of different mammals must be identified and taken into consideration when choosing tissue-contacting materials in the application of biomedical technology to physiologic research.

  11. Facile fabrication of Si mesoporous nanowires for high-capacity and long-life lithium storage

    Science.gov (United States)

    Chen, Jizhang; Yang, Li; Rousidan, Saibihai; Fang, Shaohua; Zhang, Zhengxi; Hirano, Shin-Ichi

    2013-10-01

    Si has the second highest theoretical capacity among all the known anode materials for lithium ion batteries, whereas it is vulnerable to pulverization and crumbling upon lithiation/delithiation. Herein, Si mesoporous nanowires prepared by a scalable and cost-effective procedure are reported for the first time. Such nanowire morphology and mesoporous structure can effectively buffer the huge lithiation-induced volume expansion of Si, therefore contributing to excellent cycling stability and high-rate capability. Reversible capacities of 1826.8 and 737.4 mA h g-1 can be obtained at 500 mA g-1 and a very high current density of 10 A g-1, respectively. After 1000 cycles at 2500 mA g-1, this product still maintains a high capacity of 643.5 mA h g-1.Si has the second highest theoretical capacity among all the known anode materials for lithium ion batteries, whereas it is vulnerable to pulverization and crumbling upon lithiation/delithiation. Herein, Si mesoporous nanowires prepared by a scalable and cost-effective procedure are reported for the first time. Such nanowire morphology and mesoporous structure can effectively buffer the huge lithiation-induced volume expansion of Si, therefore contributing to excellent cycling stability and high-rate capability. Reversible capacities of 1826.8 and 737.4 mA h g-1 can be obtained at 500 mA g-1 and a very high current density of 10 A g-1, respectively. After 1000 cycles at 2500 mA g-1, this product still maintains a high capacity of 643.5 mA h g-1. Electronic supplementary information (ESI) available: SEM images; N2 adsorption/desorption isotherm; long-term cycling performance at 500 mA g-1 comparison with other literature. See DOI: 10.1039/c3nr03955b

  12. Spot Welding of Honeycomb Structures

    Science.gov (United States)

    Cohal, V.

    2017-08-01

    Honeycomb structures are used to prepare meals water jet cutting machines for textile. These honeycomb structures are made of stainless steel sheet thickness of 0.1-0.2 mm. Corrugated sheet metal strips are between two gears with special tooth profile. Hexagonal cells for obtaining these strips are welded points between them. Spot welding device is three electrodes in the upper part, which carries three welding points across the width of the strip of corrugated sheet metal. Spot welding device filled with press and advance mechanisms. The paper presents the values of the regime for spot welding.

  13. Fundamental Laser Welding Process Investigations

    DEFF Research Database (Denmark)

    Bagger, Claus; Olsen, Flemming Ove

    1998-01-01

    In a number of systematic laboratory investigations the fundamental behavior of the laser welding process was analyzed by the use of normal video (30 Hz), high speed video (100 and 400 Hz) and photo diodes. Sensors were positioned to monitor the welding process from both the top side and the rear...... side of the specimen.Special attention has been given to the dynamic nature of the laser welding process, especially during unstable welding conditions. In one series of experiments, the stability of the process has been varied by changing the gap distance in lap welding. In another series...

  14. Hybrid laser-arc welding

    DEFF Research Database (Denmark)

    the characteristics of the process, including the properties of joints produced by hybrid laser-arc welding and ways of assessing weld quality. Part II discusses applications of the process to such metals as magnesium alloys, aluminium and steel as well as the use of hybrid laser-arc welding in such sectors as ship...... building and the automotive industry. With its distinguished editor and international team of contributors, Hybrid laser-arc welding, will be a valuable source of reference for all those using this important welding technology. Professor Flemming Ove Olsen works in the Department of Manufacturing...

  15. Numerical simulation of welding

    DEFF Research Database (Denmark)

    Hansen, Jan Langkjær; Thorborg, Jesper

    Aim of project:To analyse and model the transient thermal field from arc welding (SMAW, V-shaped buttweld in 15mm plate) and to some extend the mechanical response due to the thermal field. - To implement this model in a general purpose finite element program such as ABAQUS.The simulation...... stress is also taken into account.Work carried out:With few means it is possible to define a thermal model which describes the thermal field from the welding process in reasonable agreement with reality. Identical results are found with ABAQUS and Rosenthal’s analytical solution of the governing heat...... transfer equation under same conditions. It is relative easy tointroduce boundary conditions such as convection and radiation where not surprisingly the radiation has the greatest influence especially from the high temperature regions in the weld pool and the heat affected zone.Due to the large temperature...

  16. Milestones in welding technology

    Science.gov (United States)

    Dolby, Richard E.

    2013-09-01

    Sir Alan's PhD thesis describes his research into cracking during arc welding of armour steels. Throughout his career, he had a strong interest in defects of all types, how they formed in metallic structures and how the larger ones could be detected and sized by non-destructive techniques. He was also vitally concerned with how defects impacted on the engineering integrity of welded structures, particularly the risk of fracture in nuclear plant. This study presents a view of some of the major milestones in global welding technology that took place over the 60 or more years of Sir Alan's career and highlights those where he had a personal and direct involvement.

  17. Determinacy, stock market dynamics and monetary policy inertia

    DEFF Research Database (Denmark)

    Pfajfar, Damjan; Santoro, Emiliano

    2011-01-01

    We study equilibrium determinacy in a New-Keynesian model where the Central Bank responds to asset prices growth. Unlike Taylor-type rules that react to asset prices, the proposed alternative does not harm dynamic stability and in certain cases promotes determinacy by inducing interest-rate inertia....

  18. More about the moment of inertia of Mars

    Science.gov (United States)

    Kaula, William M.; Sleep, Norman H.; Phillips, Roger J.

    1989-01-01

    Differences between Mars and other terrestrial planets are discussed. Unlike other terrestrial planets, Mars has two nonhydrostatic components of moments of inertia that are nearly equal. The most probable value of I/MR-squared is slightly less than 0.3650.

  19. The Moment of Inertia of a Tennis Racket.

    Science.gov (United States)

    Brody, Howard

    1985-01-01

    Presents information on the moment of inertia of a tennis racket about its principal axes. This information (not available from conventional sources) is useful since it influences how the racket plays and how the racket feels when it is swung. In addition, measurements of motion can be easily made by undergraduate students. (JN)

  20. Device enables measurement of moments of inertia about three axes

    Science.gov (United States)

    Conn, J.

    1965-01-01

    Device measures moments of inertia of an irregularly shaped mass about three mutually perpendicular axes by the standard pendulum and torque methods. A fixture suspends the test mass at one point and can be adjusted to allow oscillation of the mass.

  1. Correcting for limb inertia and compliance in fast ergometers

    NARCIS (Netherlands)

    Hof, AL

    1997-01-01

    In fast moving ergometers for human limbs the acceleration induces transient moments due to the inertia of the limb, in combination with a not perfectly rigid limb fixation. Methods are described by which these effects can be corrected for. The correction of the moment consists of filtering the reco

  2. Moment of Inertia of a Ping-Pong Ball

    Science.gov (United States)

    Cao, Xian-Sheng

    2012-01-01

    This note describes how to theoretically calculate and experimentally measure the moment of inertia of a Ping-Pong[R] ball. The theoretical calculation results are in good agreement with the experimental measurements that can be reproduced in an introductory physics laboratory.

  3. Obstacles to Reasoning about Inertia in Different Contexts

    Science.gov (United States)

    Yerdelen-Damar, Sevda

    2015-01-01

    The present study investigated the underlying reasons for difficulties faced by students when they applied the concept of inertia across varying contexts. The participants of the study included five high school students. Data obtained from interviews were interpreted from the perspectives of the coordination class and epistemological framing…

  4. Chimera states in coupled Kuramoto oscillators with inertia

    Energy Technology Data Exchange (ETDEWEB)

    Olmi, Simona, E-mail: simona.olmi@fi.isc.cnr.it [CNR - Consiglio Nazionale delle Ricerche - Istituto dei Sistemi Complessi, via Madonna del Piano 10, I-50019 Sesto Fiorentino (Italy); INFN Sez. Firenze, via Sansone, 1 - I-50019 Sesto Fiorentino (Italy)

    2015-12-15

    The dynamics of two symmetrically coupled populations of rotators is studied for different values of the inertia. The system is characterized by different types of solutions, which all coexist with the fully synchronized state. At small inertia, the system is no more chaotic and one observes mainly quasi-periodic chimeras, while the usual (stationary) chimera state is not anymore observable. At large inertia, one observes two different kind of chaotic solutions with broken symmetry: the intermittent chaotic chimera, characterized by a synchronized population and a population displaying a turbulent behaviour, and a second state where the two populations are both chaotic but whose dynamics adhere to two different macroscopic attractors. The intermittent chaotic chimeras are characterized by a finite life-time, whose duration increases as a power-law with the system size and the inertia value. Moreover, the chaotic population exhibits clear intermittent behavior, displaying a laminar phase where the two populations tend to synchronize, and a turbulent phase where the macroscopic motion of one population is definitely erratic. In the thermodynamic limit, these states survive for infinite time and the laminar regimes tends to disappear, thus giving rise to stationary chaotic solutions with broken symmetry contrary to what observed for chaotic chimeras on a ring geometry.

  5. The Zone of Inertia: Absorptive Capacity and Organizational Change

    Science.gov (United States)

    Godkin, Lynn

    2010-01-01

    Purpose: The purpose of this paper is to describe how interruptions in organizational learning effect institutional absorptive capacity and contribute to organizational inertia. Design/methodology/approach: An exploratory model is presented as a heuristic to describe how interruptions in organizational learning affect absorptive capacity.…

  6. Fluidic Electrodynamics: On parallels between electromagnetic and fluidic inertia

    CERN Document Server

    Martins, Alexandre A

    2012-01-01

    The purpose of the present work is to trace parallels between the known inertia forces in fluid dynamics with the inertia forces in electromagnetism that are known to induce resistance forces on masses both due to acceleration and at constant velocity. It is shown that the force exerted on a particle by an ideal fluid produces two effects: i) resistance to acceleration and, ii) an increase of mass with velocity. These resistance forces arise due to the fluid dragged by the particle, where the bare mass of the particle at rest changes when in motion ("dressed" particle). It is demonstrated that the vector potential created by a charged particle in motion acts as an ideal space flow that surrounds the particle. The interaction between the particle and the entrained space flow gives rise to the observed properties of inertia and the relativistic increase of mass. Parallels are made between the inertia property of matter, electromagnetism and the hydrodynamic drag in potential flow. Accordingly, in this framework...

  7. A method for measuring the inertia properties of rigid bodies

    Science.gov (United States)

    Gobbi, M.; Mastinu, G.; Previati, G.

    2011-01-01

    A method for the measurement of the inertia properties of rigid bodies is presented. Given a rigid body and its mass, the method allows to measure (identify) the centre of gravity location and the inertia tensor during a single test. The proposed technique is based on the analysis of the free motion of a multi-cable pendulum to which the body under consideration is connected. The motion of the pendulum and the forces acting on the system are recorded and the inertia properties are identified by means of a proper mathematical procedure based on a least square estimation. After the body is positioned on the test rig, the full identification procedure takes less than 10 min. The natural frequencies of the pendulum and the accelerations involved are quite low, making this method suitable for many practical applications. In this paper, the proposed method is described and two test rigs are presented: the first is developed for bodies up to 3500 kg and the second for bodies up to 400 kg. A validation of the measurement method is performed with satisfactory results. The test rig holds a third part quality certificate according to an ISO 9001 standard and could be scaled up to measure the inertia properties of huge bodies, such as trucks, airplanes or even ships.

  8. Inaction inertia, regret, and valuation : A closer look

    NARCIS (Netherlands)

    Zeelenberg, Marcel; Nijstad, Bernard A.; van Putten, Marijke; van Dijk, Eric

    2006-01-01

    Inaction inertia is the phenomenon that one is not likely to act on an attractive opportunity after having bypassed an even more attractive opportunity. So far, all published work has assumed a causal role for the emotion regret in this effect. In a series of 5 experiments we found no support for th

  9. The Aristotelian definition of motion and the principle of inertia

    Science.gov (United States)

    McLaughlin, Thomas J.

    2001-07-01

    This dissertation argues that Newton's First Law of Motion, also known as the principle of inertia, is compatible with the Aristotelian definition of motion accepted by St. Thomas Aquinas and with the mover causality principle, which follows from that definition. The argument distinguishes Aquinas' general principles of natural philosophy from his more specific principles of nature. Thus, one can abandon Aquinas' geocentric cosmology without rejecting his entire philosophy of nature, which includes principles such as the four causes, the mover causality principle, and the definitions of motion and time. That is, the Aristotelian conception of what motion is as such does not depend upon Aquinas' accounts of gravitational, projectile, and celestial motion. After explaining what Aquinas means by the definition of motion, "the act of a being in potency insofar as it is in potency," I argue that Aquinas' view of the mover causality principle, "whatever is moved is moved by another," has been frequently misunderstood. Aquinas did not hold that the mover causality principle requires a continuously acting mover to sustain a body's motion. I then show, using Newton's examples of the First Law of Motion, his conception of inertia, the common practice of physicists and astronomers, and other arguments, that the principle of inertia requires a version of the mover causality principle that is compatible with Aquinas' own understanding. I then argue that the principle of inertia is distinct from the philosophical framework within which it has been commonly and historically conceived. In this framework, motion is no longer thought of as a coming to be but is considered a first principle or an unchanging primary quality, a view that the principle of inertia seemingly instantiates through the notion of a "state." This philosophical framework distorts the understanding of the principle of inertia. I argue that the principle of inertia is more intelligibly understood in light of the

  10. Recent Corrosion Research Trends in Weld Joints

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hwan Tae; Kil, Sang Cheol [Korea Institute of Science and Technology Information, Seoul (Korea, Republic of); Hwang, Woon Suk [Inha University, Incheon (Korea, Republic of)

    2007-04-15

    The increasing interest in the corrosion properties of weld joints in the corrosive environment is placing stringent demands on the manufacturing techniques and performance requirements, and the manufacture employs the high quality and efficiency welding process to produce welds. Welding plays an important role in the fabrication of chemical plants, nuclear power plant, ship construction, and this has led to an increasing attention to the corrosion resistant weld joints. This paper covers recent technical trends of welding technologies for corrosion resistance properties including the COMPENDEX DB analysis of welding materials, welding process, and welding fabrications

  11. Effects of welding wire composition and welding process on the weld metal toughness of submerged arc welded pipeline steel

    Institute of Scientific and Technical Information of China (English)

    De-liang Ren; Fu-ren Xiao; Peng Tian; Xu Wang; Bo Liao

    2009-01-01

    The effects of alloying elements in welding wires and submerged arc welding process on the microstructures and low-temperature impact toughness of weld metals have been investigated.The results indicate that the optimal contents of alloying elements in welding wires can improve the low-temperature impact toughness of weld metals because the proentectoid ferrite and bainite formations can be suppressed,and the fraction of acicular ferrite increases.However,the contents of alloying elements need to vary along with the welding heat input.With the increase in welding heat input,the contents of alloying elements in welding wires need to be increased accordingly.The microstructures mainly consisting of acicular ferrite can be obtained in weld metals after four-wire submerged arc welding using the wires with a low carbon content and appropriate contents of Mn,Mo,Ti-B,Cu,Ni,and RE,resulting in the high low-temperature impact toughness of weld metals.

  12. Experimental investigation and performance analysis of inertia properties measurement for heavy truck cab

    Directory of Open Access Journals (Sweden)

    Tianjun Zhu

    2015-11-01

    Full Text Available An experimental investigation and performance analysis of inertia properties measurement for heavy truck cab is presented. This method is specifically intended for measuring the inertia properties of irregular rigid bodies, and it has the potential to be applied to the measurement of the inertia properties of vehicle bodies, such as the cab, engine, and gearbox. This article, based on CATARC moment of inertia measurement system test rig, develops an accurate measuring method to identify inertia parameters of heavy truck cab. First, corresponding tests are carried out, and the lever principle and moments of inertia parallel theorem are employed to calculate and analyse the test results, which leads to the accurate value of inertia parameters. Second, the performance analysis of the proposed method is verified through the measurement error analysis. As a result, the proposed method shows high accuracy, which provides an experimental basis for accurate inertia parameter measurement of heavy truck cab.

  13. Weld penetration and defect control

    Energy Technology Data Exchange (ETDEWEB)

    Chin, B.A.

    1992-05-15

    Highly engineered designs increasingly require the use of improved materials and sophisticated manufacturing techniques. To obtain optimal performance from these engineered products, improved weld properties and joint reliability are a necessarily. This requirement for improved weld performance and reliability has led to the development of high-performance welding systems in which pre-programmed parameters are specified before any welding takes place. These automated systems however lack the ability to compensate for perturbations which arise during the welding process. Hence the need for systems which monitor and control the in-process status of the welding process. This report discusses work carried out on weld penetration indicators and the feasibility of using these indicators for on-line penetration control.

  14. Integrated sensors for robotic laser welding

    NARCIS (Netherlands)

    Iakovou, D.; Aarts, Ronald G.K.M.; Meijer, J.; Beyer, E.; Dausinger, F; Ostendorf, A; Otto, A.

    2005-01-01

    A welding head is under development with integrated sensory systems for robotic laser welding applications. Robotic laser welding requires sensory systems that are capable to accurately guide the welding head over a seam in three-dimensional space and provide information about the welding process as

  15. Infrared-Controlled Welding of Solar Cells

    Science.gov (United States)

    Paulson, R.; Finnell, S. E.; Decker, H. J.; Hodor, J. R.

    1982-01-01

    Proposed apparatus for welding large arrays of solar cells to flexible circuit substrates would sense infrared emission from welding spot. Emission would provide feedback for control of welding heat. Welding platform containing optical fibers moves upward through slots in movable holding fixture to contact solar cells. Fibers pick up infrared radiation from weld area.

  16. Sensor integration for robotic laser welding processes

    NARCIS (Netherlands)

    Iakovou, Dimitrios; Aarts, Ronald; Meijer, Johan

    2005-01-01

    The use of robotic laser welding is increasing among industrial applications, because of its ability to weld objects in three dimensions. Robotic laser welding involves three sub-processes: seam detection and tracking, welding process control, and weld seam inspection. Usually, for each sub-process,

  17. Repair welding process of friction stir welding groove defect

    Institute of Scientific and Technical Information of China (English)

    LIU Hui-jie; ZHANG Hui-jie

    2009-01-01

    The groove defect formed in the friction stir welding dramatically deteriorates weld appearances and mechanical properties of the joints owing to its larger size and penetration. Therefore, the friction stir repair welding was utilized to remove such a groove defect, and the focus was placed on the mechanical properties and microstructural characteristics of the repair joints so as to obtain an optimum repair welding process. The experimental results indicate that the groove defect can be removed by friction stir repair welding, and the offset repair welding process is superior to the symmetrical repair welding process. In the symmetrical repair welding process, a large number of fine cavity defects and an obvious aggregation of hard-brittle phase Al2Cu occur, accordingly the mechanical properties of the repair joint are weakened, and the fracture feature of repair joint is partially brittle and partially plastic. A good-quality repair joint can be obtained by the offset repair welding process, and the repair joint is fractured near the interface between the weld nugget zone and thermal-mechanically affected zone.

  18. Deconvoluting the Friction Stir Weld Process for Optimizing Welds

    Science.gov (United States)

    Schneider, Judy; Nunes, Arthur C.

    2008-01-01

    In the friction stir welding process, the rotating surfaces of the pin and shoulder contact the weld metal and force a rotational flow within the weld metal. Heat, generated by the metal deformation as well as frictional slippage with the contact surface, softens the metal and makes it easier to deform. As in any thermo-mechanical processing of metal, the flow conditions are critical to the quality of the weld. For example, extrusion of metal from under the shoulder of an excessively hot weld may relax local pressure and result in wormhole defects. The trace of the weld joint in the wake of the weld may vary geometrically depending upon the flow streamlines around the tool with some geometry more vulnerable to loss of strength from joint contamination than others. The material flow path around the tool cannot be seen in real time during the weld. By using analytical "tools" based upon the principles of mathematics and physics, a weld model can be created to compute features that can be observed. By comparing the computed observations with actual data, the weld model can be validated or adjusted to get better agreement. Inputs to the model to predict weld structures and properties include: hot working properties ofthe metal, pin tool geometry, travel rate, rotation and plunge force. Since metals record their prior hot working history, the hot working conditions imparted during FSW can be quantified by interpreting the final microstructure. Variations in texture and grain size result from variations in the strain accommodated at a given strain rate and temperature. Microstructural data from a variety of FSWs has been correlated with prior marker studies to contribute to our understanding of the FSW process. Once this stage is reached, the weld modeling process can save significant development costs by reducing costly trial-and-error approaches to obtaining quality welds.

  19. Effect of weld microstructure on weld properties in A-TIG welding of titanium alloy

    Institute of Scientific and Technical Information of China (English)

    刘凤尧; 杨春利; 林三宝; 吴林; 苏生

    2003-01-01

    Conventional TIG welding is known as its low productivity and limited weld depth in a single pass. Activating TIG welding (A-TIG) can greatly improve the penetration when compared with the conventional TIG welding. The effects of five kinds of activating fluxes with single component (NaF, CaF2, AlF3, NaCl or CaCl2) on penetration, microstructure and weld mechanical properties during the TIG welding of titanium alloy Ti-6Al-4V were studied. Compared with the conventional TIG welding, the experimental results show that the fluxes can greatly improve the penetration at the same welding specifications. This is because of the constriction of anode spots and the change of surface tension grads. Among them the effect of flux NaF is the best in the weld tensile strength, and the effect of flux CaF2 on the weld bend intension is the best. The appearance of inferior crystal grains and the structure of trident crystal grains are the main reasons that the performance of weld with fluoride is improved. These experimental results can be used as an aid for selecting suitable activating flux for titanium alloy.

  20. The effect of directional inertias added to pelvis and ankle on gait

    NARCIS (Netherlands)

    Meuleman, J.H.; Van Asseldonk, E.H.F.; Van der Kooij, H.

    2013-01-01

    Background Gait training robots should display a minimum added inertia in order to allow normal walking. The effect of inertias in specific directions is yet unknown. We set up two experiments to assess the effect of inertia in anteroposterior (AP) direction to the ankle and AP and mediolateral (ML)

  1. Development of Temper Bead Welding Process for Weld Overlay of Dissimilar Welds

    Energy Technology Data Exchange (ETDEWEB)

    Byeon, J. G.; Park, K. S.; Kim, Y. J. [Doosan Heavy Industries and Construction Co., Ltd., Seoul (Korea, Republic of)

    2008-10-15

    In recent years, the dissimilar weld metal used to connect stainless steel piping and low alloy steel or carbon steel components have experienced cracking in nuclear reactor piping systems. The cracking has been observed in several Pressurized Water Reactors in overseas. In Several cases, the cracking was repaired using structural weld overlays, a repair technique that has been in use in the U.S. in Boiling Water Reactors for over twenty years. Although weld overlays have been used primarily as a repair for flawed piping, they can also be applied at locations that have not yet exhibited any cracking, but are considered susceptible to cracking. The purpose of this research is to develop the temper bead weld process for the weld overlay of the dissimilar weld pipe. We developed equipment for the overlay system, applied Procedure Qualification(PQ) for the temper bead welding process.

  2. Fusion Welding Research.

    Science.gov (United States)

    1983-04-30

    of deep surface depresion due to vortex formation is being studied through a mathematical model. I Welding direction (a)e S (b) Figure 27: Schematic...each weldment. Specimens were cleaned in acetone and alcohol to remove grease and * dirt. They were finally cleaned ultrasonically in a detergent

  3. Thermal Stresses in Welding

    DEFF Research Database (Denmark)

    Hansen, Jan Langkjær

    1998-01-01

    Studies of the transient temperature fields and the hereby induced deformations and stressses in a butt-welded mild steel plate modelledrespectively in 2D plane stress state (as well as plane strain state) and in full 3D have been done. The model has been implemented in the generalpurpose FE...

  4. Welding. Student Learning Guide.

    Science.gov (United States)

    Palm Beach County Board of Public Instruction, West Palm Beach, FL.

    This student learning guide contains 30 modules for completing a course in welding. It is designed especially for use in secondary schools in Palm Beach County, Florida. Each module covers one task, and consists of a purpose, performance objective, enabling objectives, learning activities keyed to resources, information sheets, student self-check…

  5. SHADOW: a new welding technique

    Science.gov (United States)

    Kramer, Thorsten; Olowinsky, Alexander M.; Durand, Friedrich

    2002-06-01

    The new welding technique 'SHADOW ' is introduced. SHADOW means the use of a single pulse to generate a quasi continuous weld of several millimeters in length. HET processing time is defined by the pulse duration of the pulsed laser. At present, a state-of-the-art laser is capable of a maximum pulse duration of 20 ms. The variation of the laser power depend on time is a vital capability of the pulsed laser to adapt the energy deposition into the workpiece. Laser beam welds of several watch components were successfully performed. Similar metals like crowns and axes made out of stainless steel have been welded using pulsed laser radiation. Applying a series of about 130 single pulses for the crown-axis combination the total energy accumulates to 19.5 J. The use of the SHADOW welding technique reduces the energy to 2.5 J. While welding dissimilar metals like stainless steel and bras, the SHADOW welding reduces drastically the contamination as well as the distortion. Laser beam welding of copper has a low process reliability due to the high reflection and the high thermal conductivity. SHADOW welds of 3.6 mm length were performed on 250 micrometers thick copper plates with very high reproducibility. As a result, a pilot plant for laser beam welding of copper plates has been set up. The work to be presented has partly been funded by the European Commission in a project under the contract BRPR-CT-0634.

  6. Welding, Bonding and Fastening, 1984

    Science.gov (United States)

    Buckley, J. D. (Editor); Stein, B. A. (Editor)

    1985-01-01

    A compilation of papers presented in a joint NASA, American Society for Metals, The George Washington University, American Welding Soceity, and Society of Manufacturing Engineers conference on Welding, Bonding, and Fastening at Langley Research Center, Hampton, VA, on October 23 to 25, 1984 is given. Papers were presented on technology developed in current research programs relevant to welding, bonding, and fastening of structural materials required in fabricating structures and mechanical systems used in the aerospace, hydrospace, and automotive industries. Topics covered in the conference included equipment, hardware and materials used when welding, brazing, and soldering, mechanical fastening, explosive welding, use of unique selected joining techniques, adhesives bonding, and nondestructive evaluation. A concept of the factory of the future was presented, followed by advanced welding techniques, automated equipment for welding, welding in a cryogenic atmosphere, blind fastening, stress corrosion resistant fasteners, fastening equipment, explosive welding of different configurations and materials, solid-state bonding, electron beam welding, new adhesives, effects of cryogenics on adhesives, and new techniques and equipment for adhesive bonding.

  7. Summary of Dissimilar Metal Joining Trials Conducted by Edison Welding Institute

    Energy Technology Data Exchange (ETDEWEB)

    MJ Lambert

    2005-11-18

    Under the direction of the NASA-Glenn Research Center, the Edison Welding Institute (EWI) in Columbus, OH performed a series of non-fusion joining experiments to determine the feasibility of joining refractory metals or refractory metal alloys to Ni-based superalloys. Results, as reported by EWI, can be found in the project report for EWI Project 48819GTH (Attachment A, at the end of this document), dated October 10, 2005. The three joining methods used in this investigation were inertia welding, magnetic pulse welding, and electro-spark deposition joining. Five materials were used in these experiments: Mo-47Re, T-111, Hastelloy X, Mar M-247 (coarse-grained, 0.5 mm to several millimeter average grain size), and Mar M-247 (fine-grained, approximately 50 {micro}m average grain size). Several iterative trials of each material combination with each joining method were performed to determine the best practice joining method. Mo-47Re was found to be joined easily to Hastelloy X via inertia welding, but inertia welding of the Mo-alloy to both Mar M-247 alloys resulted in inconsistent joint strength and large reaction layers between the two metals. T-111 was found to join well to Hastelloy X and coarse-grained Mar M-247 via inertia welding, but joining to fine-grained Mar M-247 resulted in low joint strength. Magnetic pulse welding (MPW) was only successful in joining T-111 tubing to Hastelloy X bar stock. The joint integrity and reaction layer between the metals were found to be acceptable. This single joining trial, however, caused damage to the electromagnetic concentrators used in this process. Subsequent design efforts to eliminate the problem resulted in a loss of power imparted to the accelerating work piece, and results could not be reproduced. Welding trials of Mar M-247 to T-111 resulted in catastrophic failure of the bar stock, even at lower power. Electro-spark deposition joining of Mo-47Re, in which the deposited material was Hastelloy X, did not have a

  8. Small-scale explosive welding of aluminum

    Science.gov (United States)

    Bement, L. J.

    1972-01-01

    Welding technique uses very small quantities of explosive ribbon to accomplish small-scale lap-welding of aluminum plates. Technique can perform small controlled welding with no length limitations and requires minimal protective shielding.

  9. Comparison of Welding Residual Stresses of Hybrid Laser-Arc Welding and Submerged Arc Welding in Offshore Steel Structures

    DEFF Research Database (Denmark)

    Andreassen, Michael Joachim; Yu, Zhenzhen; Liu, Stephen

    2016-01-01

    induced residual stresses. It is also investigated whether the assumption of residual stresses up to yield strength magnitude are present in welded structures as stated in the design guidelines. The fatigue strength for welded joints is based on this assumption. The two welding methods investigated...... are hybrid laser-arc welding (HLAW) and submerged arc welding (SAW). Both welding methods are applied for a full penetration butt-weld of 10 mm thick plates made of thermomechanically hot-rolled, low-carbon, fine-grain S355ML grade steel used in offshore steel structures. The welding residual stress state...

  10. Study on a high capacity two-stage free piston Stirling cryocooler working around 30 K

    Science.gov (United States)

    Wang, Xiaotao; Zhu, Jian; Chen, Shuai; Dai, Wei; Li, Ke; Pang, Xiaomin; Yu, Guoyao; Luo, Ercang

    2016-12-01

    This paper presents a two-stage high-capacity free-piston Stirling cryocooler driven by a linear compressor to meet the requirement of the high temperature superconductor (HTS) motor applications. The cryocooler system comprises a single piston linear compressor, a two-stage free piston Stirling cryocooler and a passive oscillator. A single stepped displacer configuration was adopted. A numerical model based on the thermoacoustic theory was used to optimize the system operating and structure parameters. Distributions of pressure wave, phase differences between the pressure wave and the volume flow rate and different energy flows are presented for a better understanding of the system. Some characterizing experimental results are presented. Thus far, the cryocooler has reached a lowest cold-head temperature of 27.6 K and achieved a cooling power of 78 W at 40 K with an input electric power of 3.2 kW, which indicates a relative Carnot efficiency of 14.8%. When the cold-head temperature increased to 77 K, the cooling power reached 284 W with a relative Carnot efficiency of 25.9%. The influences of different parameters such as mean pressure, input electric power and cold-head temperature are also investigated.

  11. MEO based secured, robust, high capacity and perceptual quality image watermarking in DWT-SVD domain.

    Science.gov (United States)

    Gunjal, Baisa L; Mali, Suresh N

    2015-01-01

    The aim of this paper is to present multiobjective evolutionary optimizer (MEO) based highly secured and strongly robust image watermarking technique using discrete wavelet transform (DWT) and singular value decomposition (SVD). Many researchers have failed to achieve optimization of perceptual quality and robustness with high capacity watermark embedding. Here, we achieved optimized peak signal to noise ratio (PSNR) and normalized correlation (NC) using MEO. Strong security is implemented through eight different security levels including watermark scrambling by Fibonacci-Lucas transformation (FLT). Haar wavelet is selected for DWT decomposition to compare practical performance of wavelets from different wavelet families. The technique is non-blind and tested with cover images of size 512x512 and grey scale watermark of size 256x256. The achieved perceptual quality in terms of PSNR is 79.8611dBs for Lena, 87.8446 dBs for peppers and 93.2853 dBs for lake images by varying scale factor K1 from 1 to 5. All candidate images used for testing namely Lena, peppers and lake images show exact recovery of watermark giving NC equals to 1. The robustness is tested against variety of attacks on watermarked image. The experimental demonstration proved that proposed method gives NC more than 0.96 for majority of attacks under consideration. The performance evaluation of this technique is found superior to all existing hybrid image watermarking techniques under consideration.

  12. On-demand high-capacity ride-sharing via dynamic trip-vehicle assignment.

    Science.gov (United States)

    Alonso-Mora, Javier; Samaranayake, Samitha; Wallar, Alex; Frazzoli, Emilio; Rus, Daniela

    2017-01-17

    Ride-sharing services are transforming urban mobility by providing timely and convenient transportation to anybody, anywhere, and anytime. These services present enormous potential for positive societal impacts with respect to pollution, energy consumption, congestion, etc. Current mathematical models, however, do not fully address the potential of ride-sharing. Recently, a large-scale study highlighted some of the benefits of car pooling but was limited to static routes with two riders per vehicle (optimally) or three (with heuristics). We present a more general mathematical model for real-time high-capacity ride-sharing that (i) scales to large numbers of passengers and trips and (ii) dynamically generates optimal routes with respect to online demand and vehicle locations. The algorithm starts from a greedy assignment and improves it through a constrained optimization, quickly returning solutions of good quality and converging to the optimal assignment over time. We quantify experimentally the tradeoff between fleet size, capacity, waiting time, travel delay, and operational costs for low- to medium-capacity vehicles, such as taxis and van shuttles. The algorithm is validated with ∼3 million rides extracted from the New York City taxicab public dataset. Our experimental study considers ride-sharing with rider capacity of up to 10 simultaneous passengers per vehicle. The algorithm applies to fleets of autonomous vehicles and also incorporates rebalancing of idling vehicles to areas of high demand. This framework is general and can be used for many real-time multivehicle, multitask assignment problems.

  13. Incorporating magnesium and calcium cations in porous organic frameworks for high-capacity hydrogen storage.

    Science.gov (United States)

    Wang, Lin; Sun, Yingxin; Sun, Huai

    2011-01-01

    We propose incorporating a bi-functional group consisting of magnesium or calcium cations and a 1,2,4,5-benzenetetroxide anion (C6H2O4(4-)) in porous materials to enhance the hydrogen storage capacity. The C6H2O4M2 bifunctional group is highly stable and polarized, and each group provides 18 (M = Mg) or 22 (M = Ca) binding sites for hydrogen molecules with an average binding energy of ca. 10 kJ mol(-1) per hydrogen molecule based on RIMP2/ TZVPP calculations. Two porous materials (PAF-Mg or PAF-Ca) constructed with the bi-functional groups show remarkable improvement in hydrogen uptakes at normal ambient conditions. At 233 K and 10 MPa, the predicted gravimetric uptakes are 6.8 and 6.4 wt% for PAF-Mg and PAF-Ca respectively. This work reveals that fabricating materials with large numbers of binding sites and relatively low binding energies is a promising approach to achieve high capacity for on-board storage of hydrogen.

  14. A high-capacity steganography scheme for JPEG2000 baseline system.

    Science.gov (United States)

    Zhang, Liang; Wang, Haili; Wu, Renbiao

    2009-08-01

    Hiding capacity is very important for efficient covert communications. For JPEG2000 compressed images, it is necessary to enlarge the hiding capacity because the available redundancy is very limited. In addition, the bitstream truncation makes it difficult to hide information. In this paper, a high-capacity steganography scheme is proposed for the JPEG2000 baseline system, which uses bit-plane encoding procedure twice to solve the problem due to bitstream truncation. Moreover, embedding points and their intensity are determined in a well defined quantitative manner via redundancy evaluation to increase hiding capacity. The redundancy is measured by bit, which is different from conventional methods which adjust the embedding intensity by multiplying a visual masking factor. High volumetric data is embedded into bit-planes as low as possible to keep message integrality, but at the cost of an extra bit-plane encoding procedure and slightly changed compression ratio. The proposed method can be easily integrated into the JPEG2000 image coder, and the produced stego-bitstream can be decoded normally. Simulation shows that the proposed method is feasible, effective, and secure.

  15. Fast and simple high-capacity quantum cryptography with error detection

    Science.gov (United States)

    Lai, Hong; Luo, Ming-Xing; Pieprzyk, Josef; Zhang, Jun; Pan, Lei; Li, Shudong; Orgun, Mehmet A.

    2017-04-01

    Quantum cryptography is commonly used to generate fresh secure keys with quantum signal transmission for instant use between two parties. However, research shows that the relatively low key generation rate hinders its practical use where a symmetric cryptography component consumes the shared key. That is, the security of the symmetric cryptography demands frequent rate of key updates, which leads to a higher consumption of the internal one-time-pad communication bandwidth, since it requires the length of the key to be as long as that of the secret. In order to alleviate these issues, we develop a matrix algorithm for fast and simple high-capacity quantum cryptography. Our scheme can achieve secure private communication with fresh keys generated from Fibonacci- and Lucas- valued orbital angular momentum (OAM) states for the seed to construct recursive Fibonacci and Lucas matrices. Moreover, the proposed matrix algorithm for quantum cryptography can ultimately be simplified to matrix multiplication, which is implemented and optimized in modern computers. Most importantly, considerably information capacity can be improved effectively and efficiently by the recursive property of Fibonacci and Lucas matrices, thereby avoiding the restriction of physical conditions, such as the communication bandwidth.

  16. High capacity for extracellular acid-base regulation in the air-breathing fish Pangasianodon hypophthalmus.

    Science.gov (United States)

    Damsgaard, Christian; Gam, Le Thi Hong; Tuong, Dang Diem; Thinh, Phan Vinh; Huong Thanh, Do Thi; Wang, Tobias; Bayley, Mark

    2015-05-01

    The evolution of accessory air-breathing structures is typically associated with reduction of the gills, although branchial ion transport remains pivotal for acid-base and ion regulation. Therefore, air-breathing fishes are believed to have a low capacity for extracellular pH regulation during a respiratory acidosis. In the present study, we investigated acid-base regulation during hypercapnia in the air-breathing fish Pangasianodon hypophthalmus in normoxic and hypoxic water at 28-30°C. Contrary to previous studies, we show that this air-breathing fish has a pronounced ability to regulate extracellular pH (pHe) during hypercapnia, with complete metabolic compensation of pHe within 72 h of exposure to hypoxic hypercapnia with CO2 levels above 34 mmHg. The high capacity for pHe regulation relies on a pronounced ability to increase levels of HCO3(-) in the plasma. Our study illustrates the diversity in the physiology of air-breathing fishes, such that generalizations across phylogenies may be difficult.

  17. On-demand high-capacity ride-sharing via dynamic trip-vehicle assignment

    Science.gov (United States)

    Alonso-Mora, Javier; Samaranayake, Samitha; Wallar, Alex; Frazzoli, Emilio; Rus, Daniela

    2017-01-01

    Ride-sharing services are transforming urban mobility by providing timely and convenient transportation to anybody, anywhere, and anytime. These services present enormous potential for positive societal impacts with respect to pollution, energy consumption, congestion, etc. Current mathematical models, however, do not fully address the potential of ride-sharing. Recently, a large-scale study highlighted some of the benefits of car pooling but was limited to static routes with two riders per vehicle (optimally) or three (with heuristics). We present a more general mathematical model for real-time high-capacity ride-sharing that (i) scales to large numbers of passengers and trips and (ii) dynamically generates optimal routes with respect to online demand and vehicle locations. The algorithm starts from a greedy assignment and improves it through a constrained optimization, quickly returning solutions of good quality and converging to the optimal assignment over time. We quantify experimentally the tradeoff between fleet size, capacity, waiting time, travel delay, and operational costs for low- to medium-capacity vehicles, such as taxis and van shuttles. The algorithm is validated with ∼3 million rides extracted from the New York City taxicab public dataset. Our experimental study considers ride-sharing with rider capacity of up to 10 simultaneous passengers per vehicle. The algorithm applies to fleets of autonomous vehicles and also incorporates rebalancing of idling vehicles to areas of high demand. This framework is general and can be used for many real-time multivehicle, multitask assignment problems. PMID:28049820

  18. Multiresidue analysis of pesticides in vegetables and fruits using a high capacity absorbent polymer for water.

    Science.gov (United States)

    Obana, H; Akutsu, K; Okihashi, M; Kakimoto, S; Hori, S

    1999-08-01

    A single extraction and a single clean-up procedure was developed for multi-residue analysis of pesticides in non-fatty vegetables and fruits. The method involves the use of a high capacity absorbent polymer for water as a drying agent in extraction from wet food samples and of a graphitized carbon column for clean-up. A homogeneously chopped food sample (20 g) and polymer (3 g) were mixed to absorb water from the sample and then 10 min later the mixture was vigorously extracted with ethyl acetate (100 ml). The extract (50 ml), separated by filtration, was loaded on a graphitized carbon column without concentration. Additional ethyl acetate (50 ml) was also eluted and both eluates were concentrated to 5 ml for analysis. The procedure for sample preparation was completed within 2 h. In a recovery test, 107 pesticides were spiked and average recoveries were more than 80% from asparagus, orange, potato and strawberry. Most pesticides were recovered in the range 70-120% with usually less than a 10% RSD for six experiments. The results indicated that a single extraction with ethyl acetate in the presence of polymer can be applied to the monitoring of pesticide residues in foods.

  19. Li2C2, a High-Capacity Cathode Material for Lithium Ion Batteries.

    Science.gov (United States)

    Tian, Na; Gao, Yurui; Li, Yurong; Wang, Zhaoxiang; Song, Xiaoyan; Chen, Liquan

    2016-01-11

    As a typical alkaline earth metal carbide, lithium carbide (Li2C2) has the highest theoretical specific capacity (1400 mA h g(-1)) among all the reported lithium-containing cathode materials for lithium ion batteries. Herein, the feasibility of using Li2C2 as a cathode material was studied. The results show that at least half of the lithium can be extracted from Li2C2 and the reversible specific capacity reaches 700 mA h g(-1). The C≡C bond tends to rotate to form C4 (C≡C⋅⋅⋅C≡C) chains during lithium extraction, as indicated with the first-principles molecular dynamics (FPMD) simulation. The low electronic and ionic conductivity are believed to be responsible for the potential gap between charge and discharge, as is supported with density functional theory (DFT) calculations and Arrhenius fitting results. These findings illustrate the feasibility to use the alkali and alkaline earth metal carbides as high-capacity electrode materials for secondary batteries.

  20. State Violence and Oppositional Protest in High-Capacity Authoritarian Regimes

    Directory of Open Access Journals (Sweden)

    Hank Johnston

    2012-05-01

    Full Text Available This examination of the mobilization-repression nexus in high-capacity authoritarian regimes draws on examples from China, Russia, Iran, and several Middle Eastern states to develop a framework for analyzing state violence and how political oppositions are organized. The study examines middle and low levels of state violence, the provincial and municipal organization of party and regime, and the police, private militias, and thugs as low-level enforcers, and focuses on: (1 the complexity of the state’s apparatus of repression and control and how different levels exercise different forms of violence against activists; (2 the creativity of the opposition’s actions to voice its demands and avoid repression and surveillance; and (3 the recursive relationship between the two, a dark dance between state and opposition with high stakes for both. Hierarchical analysis at national, provincial, and local levels, and lateral analysis across these levels, where elite interests frequently diverge, show that intersections and gaps on both axes can create lapses in social control and openings the opposition. These free spaces of speech and innovative action give rise to novel ways to keep oppositional sentiments in the public forum. The article offers several propositions for analyzing repression and state violence at various levels, and, similarly, the various ways that these free spaces occur.

  1. An Aqueous Redox-Flow Battery with High Capacity and Power: The TEMPTMA/MV System.

    Science.gov (United States)

    Janoschka, Tobias; Martin, Norbert; Hager, Martin D; Schubert, Ulrich S

    2016-11-07

    Redox-flow batteries (RFB) can easily store large amounts of electric energy and thereby mitigate the fluctuating output of renewable power plants. They are widely discussed as energy-storage solutions for wind and solar farms to improve the stability of the electrical grid. Most common RFB concepts are based on strongly acidic metal-salt solutions or poorly performing organics. Herein we present a battery which employs the highly soluble N,N,N-2,2,6,6-heptamethylpiperidinyl oxy-4-ammonium chloride (TEMPTMA) and the viologen derivative N,N'-dimethyl-4,4-bipyridinium dichloride (MV) in a simple and safe aqueous solution as redox-active materials. The resulting battery using these electrolyte solutions has capacities of 54 Ah L(-1) , giving a total energy density of 38 Wh L(-1) at a cell voltage of 1.4 V. With peak current densities of up to 200 mA cm(-2) the TEMPTMA/MV system is a suitable candidate for compact high-capacity and high-power applications.

  2. Dynamics of space welding impact and corresponding safety welding study.

    Science.gov (United States)

    Fragomeni, James M; Nunes, Arthur C

    2004-03-01

    This study was undertaken in order to be sure that no hazard would exist from impingement of hot molten metal particle detachments upon an astronauts space suit during any future electron beam welding exercises or experiments. The conditions under which molten metal detachments might occur in a space welding environment were analyzed. The safety issue is important during welding with regards to potential molten metal detachments from the weld pool and cold filler wire during electron beam welding in space. Theoretical models were developed to predict the possibility and size of the molten metal detachment hazards during the electron beam welding exercises at low earth orbit. Some possible ways of obtaining molten metal drop detachments would include an impulse force, or bump, to the weld sample, cut surface, or filler wire. Theoretical models were determined for these detachment concerns from principles of impact and kinetic energies, surface tension, drop geometry, surface energies, and particle dynamics. A weld pool detachment parameter for specifying the conditions for metal weld pool detachment by impact was derived and correlated to the experimental results. The experimental results were for the most part consistent with the theoretical analysis and predictions.

  3. Dynamic moments of inertia in Xe, Cs and Ba nuclei

    Energy Technology Data Exchange (ETDEWEB)

    El-Samman, H.; Barci, V.; Gizon, A.; Gizon, J.; Hildingsson, L.; Jerrestam, D.; Klamra, W.; Kossakowski, R.; Lindblad, T.; Gono, Y.; Bengtsson, T.; Leander, G.A.

    1984-01-01

    The ..gamma..-rays following the reactions induced by /sup 12/C ions on /sup 115/In, /sup 112/,/sup 117/,/sup 122/Sn and /sup 123/Sb targets have been investigated using six NaI(Tl) detectors in a two-dimensional arrangement. The collective moment of inertia I(/sup 2/) /sub band/ of /sup 118/,/sup 122/Xe, /sup 123/Cs and /sup 128/,/sup 130/Ba have been extracted from the energy-correlation spectra. The behaviour of these nuclei and the observed differences are interpreted in terms of high-spin collective properties. Data are also presented on the effective moment of inertia I(/sup 2/)/sub eff/ of /sup 118/Xe and /sup 130/Ba measured by sum-spectrometer techniques. 13 references.

  4. Effects of electron inertia in collisionless magnetic reconnection

    Energy Technology Data Exchange (ETDEWEB)

    Andrés, Nahuel, E-mail: nandres@iafe.uba.ar; Gómez, Daniel [Instituto de Astronomía y Física del Espacio, CC. 67, suc. 28, 1428, Buenos Aires (Argentina); Departamento de Física, Facultad de Ciencias Exactas y Naturales, Univrsidad de Buenos Aires, Pabellón I, 1428, Buenos Aires (Argentina); Martin, Luis; Dmitruk, Pablo [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Univrsidad de Buenos Aires, Pabellón I, 1428, Buenos Aires (Argentina)

    2014-07-15

    We present a study of collisionless magnetic reconnection within the framework of full two-fluid MHD for a completely ionized hydrogen plasma, retaining the effects of the Hall current, electron pressure and electron inertia. We performed 2.5D simulations using a pseudo-spectral code with no dissipative effects. We check that the ideal invariants of the problem are conserved down to round-off errors. Our numerical results confirm that the change in the topology of the magnetic field lines is exclusively due to the presence of electron inertia. The computed reconnection rates remain a fair fraction of the Alfvén velocity, which therefore qualifies as fast reconnection.

  5. Industrial laser welding evaluation study

    Science.gov (United States)

    Hella, R.; Locke, E.; Ream, S.

    1974-01-01

    High power laser welding was evaluated for fabricating space vehicle boosters. This evaluation was made for 1/4 in. and 1/2 in. aluminum (2219) and 1/4 in. and 1/2 in. D6AC steel. The Avco HPL 10 kW industrial laser was used to perform the evaluation. The objective has been achieved through the completion of the following technical tasks: (1) parameter study to optimize welding and material parameters; (2) preparation of welded panels for MSFC evaluation; and (3) demonstration of the repeatability of laser welding equipment. In addition, the design concept for a laser welding system capable of welding large space vehicle boosters has been developed.

  6. Test Operations Procedure 01- 2- 520 Moments of Inertia

    Science.gov (United States)

    2017-08-03

    dynamics and mobility computer models, where MOI data for a vehicle’s total, sprung, and unsprung masses are often required. Moments of inertia are...information on a vehicle’s mass distribution. The properties impact vehicle design and safety and are primary inputs to vehicle dynamics and mobility ...Iyy (pitch) measurements, it is recommended that two vehicle displacement sensors be used to dynamically measure longitudinal movement of the vehicle

  7. Strategies to reduce clinical inertia in hypertensive kidney transplant recipients

    OpenAIRE

    Panek Romauld; Kiberd James; Kiberd Bryce

    2007-01-01

    Abstract Background Many kidney transplant recipients have hypertension. Elevated systolic blood pressures are associated with lower patient and kidney allograft survival. Methods This retrospective analysis examined the prevalence of clinical inertia (failure to initiate or increase therapy) in the treatment of hypertension before and after the introduction of an automated device (BpTRU) in the kidney transplant clinic. Results Historically only 36% (49/134) of patients were prescribed a cha...

  8. Factors associated with clinical inertia: an integrative review

    Directory of Open Access Journals (Sweden)

    Aujoulat I

    2014-05-01

    Full Text Available Isabelle Aujoulat,1 Patricia Jacquemin,1 Ernst Rietzschel,2 André Scheen,3 Patrick Tréfois,4 Johan Wens,5 Elisabeth Darras,1 Michel P Hermans6 1Université Catholique de Louvain, Institute of Health and Society, Brussels, 2Ghent University, Department of Cardiovascular Diseases and Department of Public Health, Faculty of Medicine and Health Sciences, Ghent, 3University of Liège, Division of Diabetes, Nutrition and Metabolic Disorders and Clinical Pharmacology Unit, CHU Liège, Liège, 4Société Scientifique de Médecine Générale, Brussels, 5University of Antwerp, Faculty of Medicine and Health Sciences, Primary and Interdisciplinary Care Antwerp, 6Université Catholique de Louvain, Institute of Experimental and Clinical Research and Cliniques Universitaires Saint-Luc, Department of Endocrinology and Nutrition, Brussels, Belgium Abstract: Failure to initiate or intensify therapy according to evidence-based guidelines is increasingly being acknowledged as a phenomenon that contributes to inadequate management of chronic conditions, and is referred to as clinical inertia. However, the number and complexity of factors associated with the clinical reasoning that underlies the decision-making processes in medicine calls for a critical examination of the consistency of the concept. Indeed, in the absence of information on and justification of treatment decisions that were made, clinical inertia may be only apparent, and actually reflect good clinical practice. This integrative review seeks to address the factors generally associated with clinical inaction, in order to better delineate the concept of true clinical inertia. Keywords: clinical inertia, evidence-based medicine, clinical decision, integrative review, concept clarification, physician adherence to guidelines

  9. Spot Welding Parameter Optimization to Improve Weld Characteristics for Dissimilar Metals

    OpenAIRE

    Aravinthan Arumugam; MohdAmizi Nor

    2015-01-01

    Abstract Resistance spot welding is a process which is widely used in the automotive industry to join steel parts of various thicknesses and types. The current practice in the automotive industry in determining the welding schedule which will be used in the welding process is based on welding table or experiences. This however may not be the optimum welding schedule that will give the best spot weld quality. This work concentrates on the parameter optimization when spot welding steels with di...

  10. Pulsed ultrasonic stir welding system

    Science.gov (United States)

    Ding, R. Jeffrey (Inventor)

    2013-01-01

    An ultrasonic stir welding system includes a welding head assembly having a plate and a rod passing through the plate. The rod is rotatable about a longitudinal axis thereof. During a welding operation, ultrasonic pulses are applied to the rod as it rotates about its longitudinal axis. The ultrasonic pulses are applied in such a way that they propagate parallel to the longitudinal axis of the rod.

  11. Viewing Welds By Computer Tomography

    Science.gov (United States)

    Pascua, Antonio G.; Roy, Jagatjit

    1990-01-01

    Computer tomography system used to inspect welds for root penetration. Source illuminates rotating welded part with fan-shaped beam of x rays or gamma rays. Detectors in circular array on opposite side of part intercept beam and convert it into electrical signals. Computer processes signals into image of cross section of weld. Image displayed on video monitor. System offers only nondestructive way to check penetration from outside when inner surfaces inaccessible.

  12. Jointed Holder For Welding Electrodes

    Science.gov (United States)

    Gilbert, Jeffrey L.

    1991-01-01

    Adjustable-angle holder enables use of standard straight electrode with custom-fabricated bent gas cup for welding in difficult-to-reach places. Electrode replaced easily, without removing cup, with aid of tool loosening miniature collet nut on holder. Consumes fewer electrodes for given amount of welding. Angle of holder continuously adjustable to fit angle of gas cup or geometry of part welded. Holder made double-jointed to accommodate gas cup having compound angles.

  13. Moment of inertia of liquid in a tank

    Directory of Open Access Journals (Sweden)

    Lee Gyeong Joong

    2014-03-01

    Full Text Available In this study, the inertial properties of fully filled liquid in a tank were studied based on the potential theory. The analytic solution was obtained for the rectangular tank, and the numerical solutions using Green’s 2nd identity were obtained for other shapes. The inertia of liquid behaves like solid in recti-linear acceleration. But under rotational acceleration, the moment of inertia of liquid becomes small compared to that of solid. The shapes of tank investigated in this study were ellipse, rectangle, hexagon, and octagon with various aspect ratios. The numerical solu¬tions were compared with analytic solution, and an ad hoc semi-analytical approximate formula is proposed herein and this formula gives very good predictions for the moment of inertia of the liquid in a tank of several different geometrical shapes. The results of this study will be useful in analyzing of the motion of LNG/LPG tanker, liquid cargo ship, and damaged ship.

  14. Probing the origin of inertia behind spacetime deformation

    CERN Document Server

    Ter_Kazarian, Gagik

    2011-01-01

    To investigate the origin and nature of inertia, we introduce a new concept of hypothetical 2D, so-called, "master-space" (MS), subject to certain rules. The MS, embedded in the background 4D-spacetime, is an indispensable individual companion to the particle of interest, without relation to every other particle. We argue that a deformation/(distortion of local internal properties) of MS is the origin of inertia. With this perspective in sight, we construct the alternative relativistic theory of inertia (RTI), which allows to compute the relativistic inertial force acting on an arbitrary point-like observer due to its "absolute acceleration". We go beyond the hypothesis of locality with an emphasis on distortion of MS, which allows to improve essentially the standard metric and other relevant geometrical structures related to the noninertial reference frame of an arbitrary accelerated observer. We compute the inertial force exerted on the photon in a gravitating system in the semi-Riemann space. Despite the t...

  15. Testing and Validation of the Dynamic Inertia Measurement Method

    Science.gov (United States)

    Chin, Alexander W.; Herrera, Claudia Y.; Spivey, Natalie D.; Fladung, William A.; Cloutier, David

    2015-01-01

    The Dynamic Inertia Measurement (DIM) method uses a ground vibration test setup to determine the mass properties of an object using information from frequency response functions. Most conventional mass properties testing involves using spin tables or pendulum-based swing tests, which for large aerospace vehicles becomes increasingly difficult and time-consuming, and therefore expensive, to perform. The DIM method has been validated on small test articles but has not been successfully proven on large aerospace vehicles. In response, the National Aeronautics and Space Administration Armstrong Flight Research Center (Edwards, California) conducted mass properties testing on an "iron bird" test article that is comparable in mass and scale to a fighter-type aircraft. The simple two-I-beam design of the "iron bird" was selected to ensure accurate analytical mass properties. Traditional swing testing was also performed to compare the level of effort, amount of resources, and quality of data with the DIM method. The DIM test showed favorable results for the center of gravity and moments of inertia; however, the products of inertia showed disagreement with analytical predictions.

  16. Flexibility and inertia of flapping wings in forward flight

    Science.gov (United States)

    Tian, Fang-Bao; Luo, Haoxiang; Lu, Xi-Yun

    2011-11-01

    Insect wings typically deform passively in flight under the combined aerodynamic force and inertia of the wing. To study the effect of the wing flexibility on the aerodynamic performance, a two-dimensional numerical study is employed to simulate the fluid-structure interaction of an elastic plate performing forward flight. The leading edge of the plate is clamped, while the rest of the chord is free to deform, leading to passive pitching and a dynamic camber. The wing stiffness and mass ratio are varied, and their effects on the lift, thrust, and aerodynamic power are investigated. The results shows that the moderate chordwise deformation can improve both lift and thrust performance significantly. The instantaneous passive pitching angle and consequently the forces are largely affected by the mass ratio that determines whether the deformation is caused by the wing inertia or the aerodynamic force. The high mass ratio wings, whose deformation is due to the wing inertia, can produce more thrust than the low mass ratio wing at the same amount of deformation. However, the high thrust is gained at a price of more power requirement. This work is sponsored by the U.S. NSF and the NSF of China.

  17. Clinical inertia: a common barrier to changing provider prescribing behavior.

    Science.gov (United States)

    Roumie, Christianne L; Elasy, Tom A; Wallston, Kenneth A; Pratt, Susan; Greevy, Robert A; Liu, Xulei; Alvarez, Vincent; Dittus, Robert S; Speroff, Theodore

    2007-05-01

    A cross-sectional content analysis nested within a randomized, controlled trial was conducted to collect information on provider responses to computer alerts regarding guideline recommendations for patients with suboptimal hypertension care. Participants were providers who cared for 1,017 patients with uncontrolled hypertension on a single antihypertensive agent within Veterans Affairs primary care clinics. All reasons for action or inaction were sorted into a framework to explain the variation in guideline adaptation. The 184 negative provider responses to computer alerts contained explanations for not changing patient treatment; 76 responses to the alerts were positive, that is, the provider was going to make a change in antihypertensive regimen. The negative responses were categorized as: inertia of practice (66%), lack of agreement with specific guidelines (5%), patient-based factors (17%), environmental factors (10%), and lack of knowledge (2%). Most of the 135 providers classified as inertia of practice indicated, "Continue current medications and I will discuss at the next visit." The median number of days until the next visit was 45 days (interquartile range, 29 to 78 days). Clinical inertia was the primary reason for failing to engage in otherwise indicated treatment change in a subgroup of patients. A framework was provided as a taxonomy for classification of provider barriers.

  18. Reconditioning medical prostheses by welding

    Science.gov (United States)

    Rontescu, C.; Cicic, D. T.; Vasile, I. M.; Bogatu, A. M.; Amza, C. G.

    2017-08-01

    After the technological process of making, some of the medical prostheses may contain imperfections, which can lead to framing the product in the spoilage category. This paper treats the possibility of reconditioning by welding of the prosthesis made of titanium alloys. The paper presents the obtained results after the reconditioning by welding, using the GTAW process, of a intramedullary rod type prosthesis in which was found a crack after the non-destructive examination. The obtained result analysis, after the micrographic examination of the welded joint areas, highlighted that the process of reconditioning by welding can be applied successfully in such situations.

  19. Pulsed ultrasonic stir welding method

    Science.gov (United States)

    Ding, R. Jeffrey (Inventor)

    2013-01-01

    A method of performing ultrasonic stir welding uses a welding head assembly to include a plate and a rod passing through the plate. The rod is rotatable about a longitudinal axis thereof. In the method, the rod is rotated about its longitudinal axis during a welding operation. During the welding operation, a series of on-off ultrasonic pulses are applied to the rod such that they propagate parallel to the rod's longitudinal axis. At least a pulse rate associated with the on-off ultrasonic pulses is controlled.

  20. High-capacity thermo-responsive magnetic molecularly imprinted polymers for selective extraction of curcuminoids.

    Science.gov (United States)

    You, Qingping; Zhang, Yuping; Zhang, Qingwen; Guo, Junfang; Huang, Weihua; Shi, Shuyun; Chen, Xiaoqin

    2014-08-08

    Thermo-responsive magnetic molecularly imprinted polymers (TMMIPs) for selective recognition of curcuminoids with high capacity and selectivity have firstly been developed. The resulting TMMIPs were characterized by TEM, FT-IR, TGA, VSM and UV, which indicated that TMMIPs showed thermo-responsiveness [lower critical solution temperature (LCST) at 33.71°C] and rapid magnetic separation (5s). The polymerization, adsorption and release conditions were optimized in detail to obtain the highest binding capacity, selectivity and release ratio. We found that the adopted thermo-responsive monomer [N-isopropylacrylamide (NIPAm)] could be considered not only as inert polymer backbone for thermo-responsiveness but also as functional co-monomers combination with basic monomer (4-VP) for more specific binding sites when ethanol was added in binding solution. The maximum adsorption capacity with highest selectivity of curcumin was 440.3μg/g (1.93 times that on MMIPs with no thermosensitivity) at 45°C (above LCST) in 20% (v/v) ethanol solution on shrunk TMMIPs, and the maximum release proportion was about 98% at 20°C (below LCST) in methanol-acetic acid (9/1, v/v) solution on swelled TMMIPs. The adsorption process between curcumin and TMMIPs followed Langumuir adsorption isotherm and pseudo-first-order reaction kinetics. The prepared TMMIPs also showed high reproducibility (RSD<6% for batch-to-batch evaluation) and stability (only 7% decrease after five cycles). Subsequently, the TMMIPs were successfully applied for selective extraction of curcuminoids from complex natural product, Curcuma longa.

  1. Spherical polystyrene-supported chitosan thin film of fast kinetics and high capacity for copper removal

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Wei, E-mail: jiangwei@nju.edu.cn; Chen, Xubin; Pan, Bingcai; Zhang, Quanxing; Teng, Long; Chen, Yufan; Liu, Lu

    2014-07-15

    Graphical abstract: - Highlights: • Sub-micron-sized polystyrene supported chitosan thin-film was synthesized. • Absorbents exhibited fast kinetics and high capacity for Cu(II) removal from water. • Absorbents could be employed for repeated use for Cu(II) removal after regeneration. - Abstract: In order to accelerate the kinetics and improve the utilization of the surface active groups of chitosan (CS) for heavy metal ion removal, sub-micron-sized polystyrene supported chitosan thin-film was synthesized by the electrostatic assembly method. Glutaraldehyde was used as cross-linking agent. Chitosan thin-film was well coated onto the surface of the polystyrene (PS) beads characterized by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). Their adsorption toward Cu(II) ions was investigated as a function of solution pH, degree of cross-linking, equilibrium Cu(II) ions concentration and contact time. The maximum adsorptive capacity of PS–CS was 99.8 mg/g in the adsorption isotherm study. More attractively, the adsorption equilibrium was achieved in 10 min, which showed superior properties among similar adsorbents. Continuous adsorption–desorption cyclic results demonstrated that Cu(II)-loaded PS–CS can be effectively regenerated by a hydrochloric acid solution (HCl), and the regenerated composite beads could be employed for repeated use without significant capacity loss, indicating the good stability of the adsorbents. The XPS analysis confirmed that the adsorption process was due to surface complexes with atoms of chitosan. Generally, PS beads could be employed as a promising host to fabricate efficient composites that originated from chitosan or other bio-sorbents for environmental remediation.

  2. A Low Cost, High Capacity Regenerable Sorbent for Pre-combustion CO{sub 2} Capture

    Energy Technology Data Exchange (ETDEWEB)

    Alptekin, Gokhan

    2012-09-30

    The overall objective of the proposed research is to develop a low cost, high capacity CO{sub 2} sorbent and demonstrate its technical and economic viability for pre-combustion CO{sub 2} capture. The specific objectives supporting our research plan were to optimize the chemical structure and physical properties of the sorbent, scale-up its production using high throughput manufacturing equipment and bulk raw materials and then evaluate its performance, first in bench-scale experiments and then in slipstream tests using actual coal-derived synthesis gas. One of the objectives of the laboratory-scale evaluations was to demonstrate the life and durability of the sorbent for over 10,000 cycles and to assess the impact of contaminants (such as sulfur) on its performance. In the field tests, our objective was to demonstrate the operation of the sorbent using actual coal-derived synthesis gas streams generated by air-blown and oxygen-blown commercial and pilot-scale coal gasifiers (the CO{sub 2} partial pressure in these gas streams is significantly different, which directly impacts the operating conditions hence the performance of the sorbent). To support the field demonstration work, TDA collaborated with Phillips 66 and Southern Company to carry out two separate field tests using actual coal-derived synthesis gas at the Wabash River IGCC Power Plant in Terre Haute, IN and the National Carbon Capture Center (NCCC) in Wilsonville, AL. In collaboration with the University of California, Irvine (UCI), a detailed engineering and economic analysis for the new CO{sub 2} capture system was also proposed to be carried out using Aspen PlusTM simulation software, and estimate its effect on the plant efficiency.

  3. Secured Data Encoding Technique in High Capacity Color Barcodes for M-Ticket Application

    Directory of Open Access Journals (Sweden)

    B. Akila

    2013-01-01

    Full Text Available This research aim is to increase the capacity of barcode (i.e. Number of data bits embedded inside barcode will be increased by encoding data through orientation modulation in elliptical dot array. BARCODES that encode digital data on physical media are commonly utilized in commercial applications for tracing/tracking of trade items, in security applications for linking personal documents with a user, or in other applications as an auxiliary channel to encode additional information on a physical medium. which are fundamentally analog, these methods can add security and functionality and features that are associated with digital techniques at the expense of consuming space on the media. For instance, in personal IDs, driving licenses and passports, high capacity can enable the encoding of a sample speech signal, a picture, or other identifying personal information which in turn may be used to establish authenticity of the user. Care must, however, be exercised in designing color barcodes to ensure that they are robust to variations in the color printing and scanning processes, which have a greater impact when considering color rather than black/white reproduction and capture.2D bar codes are being considered for new emerging applications such as M-ticketing, where they carry selected information of a ticket that is received via a mobile phone; reliable and secure personal identification, where they store personal biometric data on the identification document; and visual communications with side information, where they can be used as an auxiliary channel conveying additional data for improving visual communications.

  4. High-Capacity Layered-Spinel Cathodes for Li-Ion Batteries.

    Science.gov (United States)

    Nayak, Prasant Kumar; Levi, Elena; Grinblat, Judith; Levi, Mikhael; Markovsky, Boris; Munichandraiah, N; Sun, Yang Kook; Aurbach, Doron

    2016-09-08

    Li and Mn-rich layered oxides with the general structure x Li2 MnO3 ⋅(1-x) LiMO2 (M=Ni, Mn, Co) are promising cathode materials for Li-ion batteries because of their high specific capacity, which may be greater than 250 mA h g(-1) . However, these materials suffer from high first-cycle irreversible capacity, gradual capacity fading, limited rate capability and discharge voltage decay upon cycling, which prevent their commercialization. The decrease in average discharge voltage is a major issue, which is ascribed to a structural layered-to-spinel transformation upon cycling of these oxide cathodes in wide potential ranges with an upper limit higher than 4.5 V and a lower limit below 3 V versus Li. By using four elements systems (Li, Mn, Ni, O) with appropriate stoichiometry, it is possible to prepare high capacity composite cathode materials that contain LiMn1.5 Ni0.5 O4 and Lix Mny Niz O2 components. The Li and Mn-rich layered-spinel cathode materials studied herein exhibit a high specific capacity (≥200 mA h g(-1) ) with good capacity retention upon cycling in a wide potential domain (2.4-4.9 V). The effect of constituent phases on their electrochemical performance, such as specific capacity, cycling stability, average discharge voltage, and rate capability, are explored here. This family of materials can provide high specific capacity, high rate capability, and promising cycle life. Using Co-free cathode materials is also an obvious advantage of these systems.

  5. Binders and Hosts for High-Capacity Lithium-ion Battery Anodes

    Science.gov (United States)

    Dufficy, Martin Kyle

    Lithium-ion batteries (LIBs) are universal electrochemical energy storage devices that have revolutionized our mobile society. Nonetheless, societal and technological advances drive consumer demand for LIBs with enhanced electrochemical performance, such as higher charge capacity and longer life, compared to conventional LIBs. One method to enhance LIB performance is to replace graphite, the industry standard anode since commercialization of LIBs in 1991, with high-charge capacity materials. Implementing high-capacity anode materials such as tin, silicon, and manganese vanadates, to LIBs presents challenges; Li-insertion is destructive to anode framework, and increasing capacity increases structural strains that pulverize anode materials and results in a short-cycle life. This thesis reports on various methods to extended the cycle life of high-capacity materials. Most of the work is conducted on nano-sized anode materials to reduce Li and electron transport pathway length (facilitating charge-transfer) and reduce strains from volume expansions (preserving anode structure). The first method involves encapsulating tin particles into a graphene-containing carbon nanofiber (CNF) matrix. The composite-CNF matrix houses tin particles to assume strains from tin-volume expansions and produces favorable surface-electrolyte chemistries for stable charge-discharge cycling. Before tin addition, graphene-containing CNFs are produced and assessed as anode materials for LIBs. Graphene addition to CNFs improves electronic and mechanical properties of CNFs. Furthermore, the 2-D nature of graphene provides Li-binding sites to enhance composite-CNF both first-cycle and high-rate capacities > 150% when compared to CNFs in the absence of graphene. With addition of Sn, we vary loadings and thermal production temperature to elucidate structure-composition relationships of tin and graphene-containing CNF electrodes that lead to increased capacity retention. Of note, electrodes containing

  6. Explosive welding underwater

    Energy Technology Data Exchange (ETDEWEB)

    Sim, T.; Allen, K.; Lowes, J.M.

    1980-06-11

    Explosive welding underwater is described. First and second underwater tubular members are assembled together so that the outer surface of the first tubular member and the inner surface of the second tubular member are spaced apart to form an annular cavity. The cavity is closed by seals accommodated in portions of the second tubular member, and is then cleaned and dried and filled with a gas at a pressure greater than the surrounding water pressure. The pressure in the cavity is reduced prior to detonating an explosive charge within the first tubular member to weld the members together. The second tubular member may include portions for receiving further seals so as to subdivide the cavity into a number of zones. The pressures in the zones then can be separately adjusted so as to be able to control the pressure difference a cross each seal. 9 claims.

  7. Numerical simulation of welding

    DEFF Research Database (Denmark)

    Hansen, Jan Langkjær; Thorborg, Jesper

    Aim of project:To analyse and model the transient thermal field from arc welding (SMAW, V-shaped buttweld in 15mm plate) and to some extend the mechanical response due to the thermal field. - To implement this model in a general purpose finite element program such as ABAQUS.The simulation...... is limited to 2D and as regards the thermal model we assume plain cross section when comparing with experiments and analytical solutions.Stresses and deformations based on the thermal model is mainly described qualitatively in relation to the mechanical model in ABAQUS. As regards the mechanical model, plain...... stress is also taken into account.Work carried out:With few means it is possible to define a thermal model which describes the thermal field from the welding process in reasonable agreement with reality. Identical results are found with ABAQUS and Rosenthal’s analytical solution of the governing heat...

  8. NEW EXPLOSIVE WELDING TECHNIQUES

    OpenAIRE

    Lotous, V.; Dragobetskii, V.

    2015-01-01

    Purpose - analysis of the variety of factors of the physical phenomena accompanying the process of the power explosive effect for development of new processes of metal treatment: explosive film coating of hardening and updating of a superficial layer of an item. Industrial approbation of cladding techniques by explosion of item surfaces of complex configuration and determination of parameters of the process of the explosive welding of high-strength pig-iron (graphite of the spherical form) wi...

  9. Experimental determination of the critical welding speed in high speed MAG welding

    Institute of Scientific and Technical Information of China (English)

    Hu Zhikun; Wu Chuansong

    2008-01-01

    In high speed MAG welding process, some weld formation defects may be encountered. To get good weld quality, the critical welding speed beyond which humping or undercutting weld bead can occur must be known for different conditions. In this research, high speed MAG welding tests were carried out to check out the effects of different factors on the critical welding speed. Through observing the weld bead profiles and the macrographs of the transverse sections of MAG welds, the occurrence tendency of humping weld was analyzed, and the values of critical welding speed were determined under different levels of welding current or voltage, and the effect of shielding gas compositions on the critical welding speed was also investigated.

  10. Gas Metal Arc Welding. Welding Module 5. Instructor's Guide.

    Science.gov (United States)

    Missouri Univ., Columbia. Instructional Materials Lab.

    This guide is intended to assist vocational educators in teaching an eight-unit module in gas metal arc welding. The module is part of a welding curriculum that has been designed to be totally integrated with Missouri's Vocational Instruction Management System. The following topics are covered in the module: safety and testing, gas metal arc…

  11. Laser Welding Test Results with Gas Atmospheres in Welding Chamber

    Energy Technology Data Exchange (ETDEWEB)

    Joung, Chang-Young; Hong, Jin-Tae; Ahn, Sung-Ho; Heo, Sung-Ho; Jang, Seo-Yun; Yang, Tae-Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    The weld beads of specimens welded under identical conditions in the helium and argon gas were cleaner, more regular, and steadier than those in a vacuum. The penetration depth of the FZ in the vacuum was much deeper than those in the helium and argon gas. To measure the irradiation properties of nuclear fuel in a test reactor, a nuclear fuel test rod instrumented with various sensors must be fabricated with assembly processes. A laser welding system to assemble the nuclear fuel test rod was designed and fabricated to develop various welding technologies of the fuel test rods to joint between a cladding tube and end-caps. It is an air-cooling optical fiber type and its emission modes are a continuous (CW) mode of which the laser generates continuous emission, and pulse (QCW) mode in which the laser internally generates sequences of pulses. We considered the system welding a sample in a chamber that can weld a specimen in a vacuum and inert gas atmosphere, and the chamber was installed on the working plate of the laser welding system. In the chamber, the laser welding process should be conducted to have no defects on the sealing area between a cladding tube and an end-cap.

  12. Shielded Metal Arc Welding. Welding Module 4. Instructor's Guide.

    Science.gov (United States)

    Missouri Univ., Columbia. Instructional Materials Lab.

    This guide is intended to assist vocational educators in teaching an eight-unit module in shielded metal arc welding. The module is part of a welding curriculum that has been designed to be totally integrated with Missouri's Vocational Instruction Management System. The following topics are covered in the module: safety; theory, power sources, and…

  13. Gas Tungsten Arc Welding. Welding Module 6. Instructor's Guide.

    Science.gov (United States)

    Missouri Univ., Columbia. Instructional Materials Lab.

    This guide is intended to assist vocational educators in teaching a three-unit module in gas tungsten arc welding. The module has been designed to be totally integrated with Missouri's Vocational Instruction Management System. The basic principles involved in gas tungsten arc welding, supplies, and applications are covered. The materials included…

  14. Effects of Fusion Tack Welds on Self-Reacting Friction Stir Welds

    Science.gov (United States)

    Nunes, A. C., Jr.; Pendleton, M. L.; Brooke, S. A.; Russell, C. K.

    2012-01-01

    In order to know whether fusion tack welds would affect the strength of self-reacting friction stir seam welds in 2195-T87 aluminum alloy, the fracture stresses of 144 tensile test coupons cut from 24 welded panels containing segments of friction stir welds were measured. Each of the panels was welded under unique processing conditions. A measure of the effect of the tack welds for each panel was devised. An analysis of the measures of the tack weld effect supported the hypothesis that fusion tack welds do not affect the strength of self-reacting friction stir welds to a 5% level of confidence.

  15. Vision-based detection of MAG weld pool

    Institute of Scientific and Technical Information of China (English)

    Gao Jinqiang; Wu Chuansong; Zhang Min; Zhao Yanhua

    2007-01-01

    Weld pool contains significant information about the welding process. The weld pool images of MAG welding are detected by LaserStrobe system. An algorithm for extracting weld pool edge is proposed according to the characteristics of MAG weld pool images. The maximum weld pool length and width are calculated. The measurement data can be used to verify the results of welding process simulation and to provide a good foundation for automatic control of MAG welding process.

  16. Modeling Stress-Strain State in Butt-Welded Joints after TIG Welding

    Directory of Open Access Journals (Sweden)

    V. Atroshenko

    2015-09-01

    Full Text Available In this paper mathematical model was developed for definition of thermal-welding cycle influence on welding deformations distribution in flat samples of austenitic steels after TIG welding and developed recommendations to reduce the welding deformation on o the machinery for welding with a copper backing.

  17. [New welding processes and health effects of welding].

    Science.gov (United States)

    La Vecchia, G Marina; Maestrelli, Piero

    2011-01-01

    This paper describes some of the recent developments in the control technology to enhance capability of Pulse Gas Metal Arc Welding. Friction Stir Welding (FSW) processing has been also considered. FSW is a new solid-state joining technique. Heat generated by friction at the rotating tool softens the material being welded. FSW can be considered a green and energy-efficient technique without deleterious fumes, gas, radiation, and noise. Application of new welding processes is limited and studies on health effects in exposed workers are lacking. Acute and chronic health effects of conventional welding have been described. Metal fume fever and cross-shift decline of lung function are the main acute respiratory effects. Skin and eyes may be affected by heat, electricity and UV radiations. Chronic effects on respiratory system include chronic bronchitis, a benign pneumoconiosis (siderosis), asthma, and a possible increase in the incidence of lung cancer. Pulmonary infections are increased in terms of severity, duration, and frequency among welders.

  18. Technology Assessment of High Capacity Data Storage Systems: Can We Avoid a Data Survivability Crisis?

    Science.gov (United States)

    Halem, M.; Shaffer, F.; Palm, N.; Salmon, E.; Raghavan, S.; Kempster, L.

    1998-01-01

    This technology assessment of long-term high capacity data storage systems identifies an emerging crisis of severe proportions related to preserving important historical data in science, healthcare, manufacturing, finance and other fields. For the last 50 years, the information revolution, which has engulfed all major institutions of modem society, centered itself on data-their collection, storage, retrieval, transmission, analysis and presentation. The transformation of long term historical data records into information concepts, according to Drucker, is the next stage in this revolution towards building the new information based scientific and business foundations. For this to occur, data survivability, reliability and evolvability of long term storage media and systems pose formidable technological challenges. Unlike the Y2K problem, where the clock is ticking and a crisis is set to go off at a specific time, large capacity data storage repositories face a crisis similar to the social security system in that the seriousness of the problem emerges after a decade or two. The essence of the storage crisis is as follows: since it could take a decade to migrate a peta-byte of data to a new media for preservation, and the life expectancy of the storage media itself is only a decade, then it may not be possible to complete the transfer before an irrecoverable data loss occurs. Over the last two decades, a number of anecdotal crises have occurred where vital scientific and business data were lost or would have been lost if not for major expenditures of resources and funds to save this data, much like what is happening today to solve the Y2K problem. A pr-ime example was the joint NASA/NSF/NOAA effort to rescue eight years worth of TOVS/AVHRR data from an obsolete system, which otherwise would have not resulted in the valuable 20-year long satellite record of global warming. Current storage systems solutions to long-term data survivability rest on scalable architectures

  19. The catalytic reactions in the Cu-Li-Mg-H high capacity hydrogen storage system.

    Science.gov (United States)

    Braga, M H; El-Azab, A

    2014-11-14

    A family of hydrides, including the high capacity MgH2 and LiH, is reported. The disadvantages these hydrides normally display (high absorption/desorption temperatures and poor kinetics) are mitigated by Cu-hydride catalysis. This paper reports on the synthesis of novel CuLi0.08Mg1.42H4 and CuLi0.08Mg1.92H5 hydrides, which are structurally and thermodynamically characterized for the first time. The CuLi0.08Mg1.42H4 hydride structure in nanotubes is able to hold molecular H2, increasing the gravimetric and volumetric capacity of this compound. The catalytic effect these compounds show on hydride formation and decomposition of CuMg2 and Cu2Mg/MgH2, Li and LiH, Mg and MgH2 is analyzed. The Gibbs energy, decomposition temperature, and gravimetric capacity of the reactions occurring within the Cu-Li-Mg-H system are presented for the first time. First principles and phonon calculations are compared with experiments, including neutron spectroscopy. It is demonstrated that the most advantageous sample contains CuLi0.08Mg1.92 and (Li) ∼ Li2Mg3; it desorbs/absorbs hydrogen according to the reaction, 2CuLi0.08Mg1.42H4 + 2Li + 4MgH2 ↔ 2CuLi0.08Mg1.92 + Li2Mg3 + 8H2 at 114 °C (5.0 wt%) - 1 atm, falling within the proton exchange membrane fuel cell applications window. Finally the reaction 2CuLi0.08Mg1.42H4 + MgH2 ↔ 2CuLi0.08Mg1.92 + 5H2 at 15 °C (4.4 wt%) - 1 atm is found to be the main reaction of the samples containing CuLi0.08Mg1.92 that were analyzed in this study.

  20. New explosive seam welding concepts

    Science.gov (United States)

    Bement, L. J.

    1973-01-01

    Recently developed techniques provide totally-confined linear explosive seam welding and produce scarf joint with linear explosive seam welding. Linear ribbon explosives are utilized in making narrow, continuous, airtight joints in variety of aluminum alloys, titanium, copper, brass, and stainless steel.

  1. Shedding Light on Laser Welding

    NARCIS (Netherlands)

    Aalderink, B.J.; Aalderink, Benno; Aarts, Ronald G.K.M.; Jonker, Jan B.; Meijer, J.

    2005-01-01

    Nd:YAG laser welding is often used in industry to obtain high quality joints. This however does not mean that monitoring or control of this process is common practice. A few commercial products are available but none of these systems can be used for monitoring the laser welding process of aluminium.

  2. Plasticity Theory of Fillet Welds

    DEFF Research Database (Denmark)

    Hansen, Thomas

    2005-01-01

    This paper deals with simple methods for calculation of fillet welds based on the theory of plasticity. In developing the solutions the lower-bound theorem is used. The welding material and parts of the base material are subdivided into triangular regions with homogeneous stress fields; thereby...

  3. 49 CFR 179.300-9 - Welding.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Welding. 179.300-9 Section 179.300-9... Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.300-9 Welding. (a) Longitudinal... fusion welded on class DOT-110A tanks. Welding procedures, welders and fabricators must be approved...

  4. METHOD AND SYSTEM FOR LASER WELDING

    DEFF Research Database (Denmark)

    2008-01-01

    The invention relates to laser welding of at least two adjacent, abutting or overlapping work pieces in a welding direction using multiple laser beams guided to a welding region, wherein at least two of the multiple laser beams are coupled into the welding region so as to form a melt and at least...

  5. Image Control In Automatic Welding Vision System

    Science.gov (United States)

    Richardson, Richard W.

    1988-01-01

    Orientation and brightness varied to suit welding conditions. Commands from vision-system computer drive servomotors on iris and Dove prism, providing proper light level and image orientation. Optical-fiber bundle carries view of weld area as viewed along axis of welding electrode. Image processing described in companion article, "Processing Welding Images for Robot Control" (MFS-26036).

  6. Friction Stir Welding of Aluminum Alloys

    Institute of Scientific and Technical Information of China (English)

    FU Zhi-hong; HE Di-qiu; WANG Hong

    2004-01-01

    Friction stir welding(FSW), a new solid-state welding technology invited in the early 1990s,enables us weld aluminum alloys and titanium alloys etc. The processing of FSW, the microstructure in FSW alloysand the factors influencing weld quality are introduced. The complex factors affecting the properties are researched.

  7. Image Control In Automatic Welding Vision System

    Science.gov (United States)

    Richardson, Richard W.

    1988-01-01

    Orientation and brightness varied to suit welding conditions. Commands from vision-system computer drive servomotors on iris and Dove prism, providing proper light level and image orientation. Optical-fiber bundle carries view of weld area as viewed along axis of welding electrode. Image processing described in companion article, "Processing Welding Images for Robot Control" (MFS-26036).

  8. Explosive welding finds uses offshore

    Energy Technology Data Exchange (ETDEWEB)

    1984-02-01

    This article discusses an explosive welding procedure for pipeline repair. Unlike fusion welding, explosive welding does not leave a brittle area behind and will stop axial or longitudinal cracking of a pipeline. The metals are joined by cold impact pressure, which actually liquifies the metal at the point of impact. In explosive welding, the force of the circular explosion drives the two metals together with such an impact that a bonded wave pattern is set up. All surface defects and oxides are pushed ahead of the collision front, resulting in a metal-to-metal seal. Two techniques are reviewed: the Exploweld method and the Norabel method. Both methods do not reduce or expand the internal diameter of the welded surface.

  9. Reduction of Biomechanical and Welding Fume Exposures in Stud Welding.

    Science.gov (United States)

    Fethke, Nathan B; Peters, Thomas M; Leonard, Stephanie; Metwali, Mahmoud; Mudunkotuwa, Imali A

    2016-04-01

    The welding of shear stud connectors to structural steel in construction requires a prolonged stooped posture that exposes ironworkers to biomechanical and welding fume hazards. In this study, biomechanical and welding fume exposures during stud welding using conventional methods were compared to exposures associated with use of a prototype system that allowed participants to weld from an upright position. The effect of base material (i.e. bare structural beam versus galvanized decking) on welding fume concentration (particle number and mass), particle size distribution, and particle composition was also explored. Thirty participants completed a series of stud welding simulations in a local apprenticeship training facility. Use of the upright system was associated with substantial reductions in trunk inclination and the activity levels of several muscle groups. Inhalable mass concentrations of welding fume (averaged over ~18 min) when using conventional methods were high (18.2 mg m(-3) for bare beam; 65.7 mg m(-3) for through deck), with estimated mass concentrations of iron (7.8 mg m(-3) for bare beam; 15.8 mg m(-3) for through deck), zinc (0.2 mg m(-3) for bare beam; 15.8 mg m(-3) for through deck), and manganese (0.9 mg m(-3) for bare beam; 1.5 mg m(-3) for through deck) often exceeding the American Conference of Governmental Industrial Hygienists Threshold Limit Values (TLVs). Number and mass concentrations were substantially reduced when using the upright system, although the total inhalable mass concentration remained above the TLV when welding through decking. The average diameters of the welding fume particles for both bare beam (31±17 nm) through deck conditions (34±34 nm) and the chemical composition of the particles indicated the presence of metallic nanoparticles. Stud welding exposes ironworkers to potentially high levels of biomechanical loading (primarily to the low back) and welding fume. The upright system used in this study improved exposure

  10. Spot Welding Parameter Optimization to Improve Weld Characteristics for Dissimilar Metals

    Directory of Open Access Journals (Sweden)

    Aravinthan Arumugam

    2015-01-01

    Full Text Available Abstract Resistance spot welding is a process which is widely used in the automotive industry to join steel parts of various thicknesses and types. The current practice in the automotive industry in determining the welding schedule which will be used in the welding process is based on welding table or experiences. This however may not be the optimum welding schedule that will give the best spot weld quality. This work concentrates on the parameter optimization when spot welding steels with dissimilar thickness and type using Grey Based Taguchi Method. The experimentation in this work used a L9 orthogonal array with three factors with each factor having three levels. The three factors used are welding current weld time and electrode force. The three weld characteristics that were optimized are weld strength weld nugget diameter and weld indentation. The analysis of variance ANOVA that was carried out showed that welding current gave the most significant contribution in the optimum welding schedule. The comparison test that was carried out to compare the current welding schedule and the optimum welding schedule showed distinct improvement in the increase of weld diameter and weld strengthas well as decrease in electrode indentation.

  11. Friction stir welding of copper alloys

    Institute of Scientific and Technical Information of China (English)

    Liu Shuhua; Liu Meng; Wang Deqing; Xu Zhenyue

    2007-01-01

    Copper plates,brass plates and copper/brass plates were friction stir welded with various parameters. Experimental results show that the microstructure of the weld is characterized by its much finer grains as contrasted with the coarse grains of parent materials and the heat-affected zones are very narrow. The microhardness of the copper weld is a little higher than that of parent plate. The microhardness of brass weld is about 25% higher than that of parent material. The tensile strength of copper joints increases with increasing welding speed in the test range. The range of parameters to obtain good welds for copper is much wider than that for brass. When different materials were welded, the position of copper plate before welding affected the quality of FSW joints. If the copper plate was put on the advancing side of weld, the good quality of weld could be got under proper parameters.

  12. Quantised inertia from relativity and the uncertainty principle

    CERN Document Server

    McCulloch, M E

    2016-01-01

    It is shown here that if we assume that what is conserved in nature is not simply mass-energy, but rather mass-energy plus the energy uncertainty of the uncertainty principle, and if we also assume that position uncertainty is reduced by the formation of relativistic horizons, then the resulting increase of energy uncertainty is close to that needed for a new model for inertial mass (MiHsC, quantised inertia) which has been shown to predict galaxy rotation without dark matter and cosmic acceleration without dark energy. The same principle can also be used to model the inverse square law of gravity, and predicts the mass of the electron.

  13. A determination of the lunar moment of inertia

    Science.gov (United States)

    Gapcynski, J. P.; Blackshear, W. T.; Tolson, R. H.; Compton, H. R.

    1975-01-01

    An estimate of the second zonal coefficient of the spherical-harmonic representation of the lunar gravitational field has been obtained from an analysis of particular orbital-element variations of the Explorer 35 and Explorer 49 spacecraft. Data from these spacecraft were used because the orbital configurations resulted in variations of the longitude of periapse and node which were, to first order, dependent only on the even zonal harmonics. The data time span for each satellite was extremely long: 2138 days for Explorer 35 and 230 days for Explorer 49. The value of the harmonic coefficient is determined and used to obtain a value of the lunar moment of inertia.

  14. Continuous breakdown of Purcell's scallop theorem with inertia

    CERN Document Server

    Lauga, Eric

    2007-01-01

    Purcell's scallop theorem defines the type of motions of a solid body - reciprocal motions - which cannot propel the body in a viscous fluid with zero Reynolds number. For example, the flapping of a wing is reciprocal and, as was recently shown, can lead to directed motion only if its frequency Reynolds number, Re_f, is above a critical value of order one. Using elementary examples, we show the existence of oscillatory reciprocal motions which are effective for all arbitrarily small values of the frequency Reynolds number and induce net velocities scaling as (Re_f)^\\alpha (alpha > 0). This demonstrates a continuous breakdown of the scallop theorem with inertia.

  15. Money Illusion and Nominal Inertia in Experimental Asset Markets

    DEFF Research Database (Denmark)

    Noussair, Charles N.; Richter, Gregers; Tyran, Jean-Robert

    We test whether large but purely nominal shocks affect real asset market prices. We subject a laboratory asset market to an exogenous shock, which either inflates or deflates the nominal fundamental value of the asset, while holding the real fundamental value constant. After an inflationary shock......, nominal prices adjust upward rapidly and we observe no real effects. However, after a deflationary shock, nominal prices display considerable inertia and real prices adjust only slowly and incompletely toward the levels that would prevail in the absence of a shock. Thus, an asymmetry is observed...... in the price response to inflationary and deflationary nominal shocks....

  16. Accounting for inertia in modal choices: some new evidence using a RP/SP dataset

    DEFF Research Database (Denmark)

    Cherchi, Elisabetta; Manca, Francesco

    2011-01-01

    effect is stable along the SP experiments. Inertia has been studied more extensively with panel datasets, but few investigations have used RP/SP datasets. In this paper we extend previous work in several ways. We test and compare several ways of measuring inertia, including measures that have been...... proposed for both short and long RP panel datasets. We also explore new measures of inertia to test for the effect of “learning” (in the sense of acquiring experience or getting more familiar with) along the SP experiment and we disentangle this effect from the pure inertia effect. A mixed logit model...... is used that allows us to account for both systematic and random taste variations in the inertia effect and for correlations among RP and SP observations. Finally we explore the relation between the utility specification (especially in the SP dataset) and the role of inertia in explaining current choices....

  17. Atmospheric effects on the mapping of Martian thermal inertia and thermally derived albedo

    Science.gov (United States)

    Hayashi, Joan N.; Jakosky, Bruce M.; Haberle, Robert M.

    1995-01-01

    We examine the effects of a dusty CO2 atmosphere on the thermal inertia and thermally derived albedo of Mars and we present a new map of thermal inertias. This new map was produced using a coupled surface atmosphere (CSA) model, dust opacities from Viking infrared thermal mapper (IRTM) data, and CO2 columns based on topography. The CSA model thermal inertias are smaller than the 2% model thermal inertias, with the difference largest at large thermal inertia. Although the difference between the thermal inertias obtained with the two models is moderate for much of the region studied, it is largest in regions of either high dust opacity or of topographic lows, including the Viking Lander 1 site and some geologically interesting regions. The CSA model thermally derived albedos do not acurately predict the IRTM measured albedos and are very similar to the thermally derived albedos obtained with models making the 2% assumption.

  18. DETECTION AND ANALYSIS OF WELD POOL SHAPE FOR CO2 SHORT CIRCUITING ARC WELDING

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A general industrial CCD(ICCD) camera is redesigned to detect the weld pool without arc at the period of short circuiting,so that the interference of arc and spatter during CO2 short circuiting arc welding is eliminated. Through the analysis of weld pool image, both size parameters (such as weld pool area A, weld pool length L1, L2 and weld pool breadth b) and contour parameters (bi which describe the curves of weld pool boundany) ,which could indicate the shape features of weld pool, had been defined to express weld pool information quantitatively. The investigation of the relationships between weld pool shape parameters and welding process parameters may be beneficial to the quality control of CO2 welding.

  19. Weld Metal Cooling Rate Indicator System.

    Science.gov (United States)

    rate of change of weld temperature at the predetermined weld temperature. A range of...provided so that the rate of change of weld temperatures at the predetermined weld temperature can be compared with this range. A device is then provided...which is responsive to the comparing information for indicating whether the rate of change of weld temperature is within, above, or below the range

  20. Corrosion Properties of Laser Welded Stainless Steel

    DEFF Research Database (Denmark)

    Weldingh, Jakob; Olsen, Flemmming Ove

    1997-01-01

    In this paper the corrosion properties of laser welded AISI 316L stainless steel are examined. A number of different welds has been performed to test the influence of the weld parameters of the resulting corrosion properties. It has been chosen to use the potential independent critical pitting...... temperature (CPT) test as corrosion test. The following welding parameters are varied: Welding speed, lsser power, focus point position and laser operation mode (CW or pulsed)....

  1. SLC2A9 is a high-capacity urate transporter in humans.

    Directory of Open Access Journals (Sweden)

    Mark J Caulfield

    2008-10-01

    0.98, 95% confidence interval [CI] 0.9 to 1.05, p > 0.33 by meta-analysis of an SLC2A9 variant in six case-control studies including 11,897 participants. In a separate meta-analysis of four population studies including 11,629 participants we found no association of SLC2A9 with systolic (effect size -0.12 mm Hg, 95% CI -0.68 to 0.43, p = 0.664 or diastolic blood pressure (effect size -0.03 mm Hg, 95% CI -0.39 to 0.31, p = 0.82. CONCLUSIONS: This study provides evidence that SLC2A9 splice variants act as high-capacity urate transporters and is one of the first functional characterisations of findings from genome-wide association scans. We did not find an association of the SLC2A9 gene with blood pressure in this study. Our findings suggest potential pathogenic mechanisms that could offer a new drug target for gout.

  2. Morphology control of ordered mesoporous carbons for high capacity lithium sulfur batteries

    Energy Technology Data Exchange (ETDEWEB)

    Schuster, Joerg David

    2011-06-07

    The focus of this thesis concerns the morphology control of ordered mesoporous carbon (OMC) materials. Ordered mesoporous carbons with diverse morphologies, that are thin films, fibers - embedded in anodic alumina membranes and free-standing - or spherical nanoparticles, have been successfully prepared by soft-templating procedures. The mechanisms of structure formation and processing were investigated with in-situ SAXS measurements and their application in high capacity lithium-sulfur batteries was successfully tested in cooperation with Guang He and Linda Nazar from the University of Waterloo in Canada. The Li-S batteries receive increasing attention due to their high theoretical energy density which is 3 to 5 times higher than from lithium-ion batteries. For this type of battery the specific pore volume is crucial for the content of the active component (sulfur) in the cathode and therefore correlates with the capacity and gravimetric energy density of the battery. At first, mesoporous thin films with 2D-hexagonal structure were obtained through organic-organic self-assembly of a preformed oligomeric resol precursor and the triblock copolymer template Pluronic P123. The formation of a condensed-wall material through thermopolymerization of the precursor oligomers resulted in mesostructured phenolic resin films. Subsequent decomposition of the surfactant and partial carbonization were achieved through thermal treatment in inert atmosphere. The films were crack-free with tunable homogenous thicknesses, and showed either 2D-hexagonal or lamellar mesostructure. An additional, yet unknown 3D-mesostructure was also found. In the second part, cubic and circular hexagonal mesoporous carbon phases in the confined environment of tubular anodic alumina membrane (AAM) pores were obtained by self-assembly of the mentioned resol precursor and the triblock copolymer templates Pluronic F127 or P123, respectively. Casting and solvent-evaporation were also followed by

  3. Semiclassical shell-structure moment of inertia within the phase-space approach

    OpenAIRE

    Gorpinchenko, D. V.; Magner, A. G.; Bartel, J; Blocki, J. P.

    2014-01-01

    The moment of inertia for nuclear collective rotations was derived within the semiclassical approach based on the cranking model and the Strutinsky shell-correction method by using the non-perturbative periodic-orbit theory in the phase space variables. This moment of inertia for adiabatic (statistical-equilibrium) rotations can be approximated by the generalized rigid-body moment of inertia accounting for the shell corrections of the particle density. A semiclassical phase-space trace formul...

  4. Moment of inertia of a trapped superfluid gas of atomic fermions

    OpenAIRE

    Farine, M.; Schuck, Peter; Viñas Gausí, Xavier

    2000-01-01

    The moment of inertia of a trapped superfluid gas of atomic Fermions (6Li) is calculated as a function of two system parameters: temperature and deformation of the trap. For moderate deformations at zero temperature the moment of inertia takes on the irrotational flow value. Only for T very close to the critical temperature rigid rotation is attained. For very strong trap deformations the moment of inertia approaches its rigid body value even in the superfluid state. It is proposed that futur...

  5. Design of PID Controller for Maglev System Based on an Improved PSO with Mixed Inertia Weight

    Directory of Open Access Journals (Sweden)

    Rongrong Song

    2014-06-01

    Full Text Available A Maglev system was modeled by the exact feedback linearization to achieve two same linear subsystems. The proportional-integral-differential controllers (PID based on particle swarm optimization (PSO algorithm with four different inertia weights were then used to regulate both linear subsystems. These different inertia weights were Fixed Inertia Weight (FIW, Linear Descend Inertia Weight (LIW, Linear Differential Descend Inertia Weight (LDW, and mixed inertia weight (FIW–LIW-LDW. On the other hand, the parameters  of the PSO-PID controllers via mixed inertia weight (FIW–LIW-LDW were optimized, the parameter values  in the electromagnet 1 and electromagnet 2 were both 0.4. Simulation results demonstrate that the control performance and robustness of PSO-PID based on mixed inertia weight (FIW–LIW-LDW was superior to that of three PSO-PID controllers based on single inertia weights. For electromagnet 1, the overshoot of PSO-PID controller with mixed inertia weight reduced 3.36% than that of PSO-PID controller with FIW, 5.81% than that of PSO-PID controller with LIW, and 6.34% than that of PSO-PID controller with LDW; for electromagnet 2, the overshoot of PSO-PID controller with mixed inertia weight reduced 1.07% than that of PSO-PID controller with FIW, 12.56% than that of PSO-PID controller with LIW, 7.97% than that of PSO-PID controller with LDW; the adjusting time of PSO-PID controller with mixed inertia weight reduced 0.395s than that of PSO-PID controller with FIW, 34.1s than that of PSO-PID controller with LIW, and 33.494s than that of PSO-PID controller with LDW

  6. Evaluating the impact of investments in information technology on structural inertia in health organizations.

    Science.gov (United States)

    Bewley, Lee W

    2010-01-01

    Structural inertia is the overall capacity of an organization to adapt within a market environment. This paper reviews the impact of healthcare investments in information management/information technology (IM/IT) on the strategic management concept of structural inertia. Research indicates that healthcare executives should consider the relative state of structural inertia for their firms and match them with potential IM/IT solutions. Additionally, organizations should favorably consider IM/IT solutions that are comparatively less complex.

  7. Versatile Friction Stir Welding/Friction Plug Welding System

    Science.gov (United States)

    Carter, Robert

    2006-01-01

    A proposed system of tooling, machinery, and control equipment would be capable of performing any of several friction stir welding (FSW) and friction plug welding (FPW) operations. These operations would include the following: Basic FSW; FSW with automated manipulation of the length of the pin tool in real time [the so-called auto-adjustable pin-tool (APT) capability]; Self-reacting FSW (SRFSW); SR-FSW with APT capability and/or real-time adjustment of the distance between the front and back shoulders; and Friction plug welding (FPW) [more specifically, friction push plug welding] or friction pull plug welding (FPPW) to close out the keyhole of, or to repair, an FSW or SR-FSW weld. Prior FSW and FPW systems have been capable of performing one or two of these operations, but none has thus far been capable of performing all of them. The proposed system would include a common tool that would have APT capability for both basic FSW and SR-FSW. Such a tool was described in Tool for Two Types of Friction Stir Welding (MFS- 31647-1), NASA Tech Briefs, Vol. 30, No. 10 (October 2006), page 70. Going beyond what was reported in the cited previous article, the common tool could be used in conjunction with a plug welding head to perform FPW or FPPW. Alternatively, the plug welding head could be integrated, along with the common tool, into a FSW head that would be capable of all of the aforementioned FSW and FPW operations. Any FSW or FPW operation could be performed under any combination of position and/or force control.

  8. Rheology of welding: Field constraints

    Science.gov (United States)

    Russell, K.; Quane, S.

    2003-04-01

    Pyroclastic deposits emplaced at high temperature and having sufficient thickness become welded via sintering, compaction and flattening of hot glassy particles. The welding process is attended by pronounced changes in the physical properties of the deposit and welding intensity can be tracked by measuring the density, porosity, fabric or strength of samples. Ultimately, the intensity of welding reflects the aggregate effects of load and residence time at temperatures above the glass transition temperature (Tg). This results in welding intensity varying with stratigraphic depth; vertical sections through welded ignimbrite deposits commonly show maximum (e.g., density) or minimum (porosity) values in physical properties in the lower half (30--40% above the base) of the unit. Here we explore the extent to which these data, serving as proxies for strain, can be used constrain the rheological properties of the pyroclastic deposit during the welding process. Our data include measurements of density, porosity, fabric and rock strength as a function of stratigraphic position for 4 sections through the Bandelier tuff, New Mexico. These profiles record changes in physical properties and, thus, map the cumulative strain associated with welding as a function of depth (load). We have used simple conductive heat transfer models to estimate cooling curves for each sample. Essentially, these curves provide the residence time within the "welding window" for each sample. The curves are dependent on sample position, thickness of ignimbrite, emplacement temperature and the glass transition temperature of the material. The unknowns in the problem are a number of physical constants in a generalized power-law relationship between strain-rate (ɛ') and stress (σ) for steady-state creep at constant load: ɛ' = A σ^n e[-Q/R T]. Specifically, we adopt an inverse-model approach whereby the observations on the natural material are used to constrain the pre-exponential constant (A), stress

  9. Study of Gasdynamic Effect Upon the Weld Geometry When Concumable Electrode Welding

    Science.gov (United States)

    Chinakhov, D. A.; Grigorieva, E. G.; Mayorova, E. I.

    2016-04-01

    The paper considers the ways of weld geometry controlling when consumable electrode welding under single-jet and double-jet gas shielding. The authors provide comparative results of experimental studies on the effects of shielding gas supply upon the weld geometry in weld joints produced from construction carbon steel 45. It has been established that gas-dynamic effect of the shielding gas has a significant impact upon shaping and weld geometry when consumable electrode welding under double-jet gas shielding.

  10. Changes in inertia and effect on turning effort across different wheelchair configurations.

    Science.gov (United States)

    Caspall, Jayme J; Seligsohn, Erin; Dao, Phuc V; Sprigle, Stephen

    2013-01-01

    When executing turning maneuvers, manual wheelchair users must overcome the rotational inertia of the wheelchair system. Differences in wheelchair rotational inertia can result in increases in torque required to maneuver, resulting in greater propulsion effort and stress on the shoulder joints. The inertias of various configurations of an ultralightweight wheelchair were measured using a rotational inertia-measuring device. Adjustments in axle position, changes in wheel and tire type, and the addition of several accessories had various effects on rotational inertias. The configuration with the highest rotational inertia (solid tires, mag wheels with rearward axle) exceeded the configuration with the lowest (pneumatic tires, spoke wheels with forward axle) by 28%. The greater inertia requires increased torque to accelerate the wheelchair during turning. At a representative maximum acceleration, the reactive torque spanned the range of 11.7 to 15.0 N-m across the wheelchair configurations. At higher accelerations, these torques exceeded that required to overcome caster scrub during turning. These results indicate that a wheelchair's rotational inertia can significantly influence the torque required during turning and that this influence will affect active users who turn at higher speeds. Categorizing wheelchairs using both mass and rotational inertia would better represent differences in effort during wheelchair maneuvers.

  11. Sytematics of dynamic moment of inertia in super-deformed bands in Mass ~150 region

    CERN Document Server

    Roy, S

    2016-01-01

    An empirical semi-classical model have been proposed to investigate the nature of dynamic moment-of-inertia , of the super-deformed (SD) bands in nuclei of mass 150 region. The model incorporates an additional frequency dependent distortion, to the dynamic moment-of-inertia term akin to a vibrational component to explain the extreme spin structure of these bands. Using this model two separate components to the dynamic moment of inertia, $\\Im^{(2)}$ have been identified for the SD band structure for the mass 150 region. Three distinct nature of the moment-of-inertia, also have been identified using the two parameter model.

  12. Changes in inertia and effect on turning effort across different wheelchair configurations

    Directory of Open Access Journals (Sweden)

    Jayme J. Caspall, MS

    2014-02-01

    Full Text Available When executing turning maneuvers, manual wheelchair users must overcome the rotational inertia of the wheelchair system. Differences in wheelchair rotational inertia can result in increases in torque required to maneuver, resulting in greater propulsion effort and stress on the shoulder joints. The inertias of various configurations of an ultralightweight wheelchair were measured using a rotational inertia-measuring device. Adjustments in axle position, changes in wheel and tire type, and the addition of several accessories had various effects on rotational inertias. The configuration with the highest rotational inertia (solid tires, mag wheels with rearward axle exceeded the configuration with the lowest (pneumatic tires, spoke wheels with forward axle by 28%. The greater inertia requires increased torque to accelerate the wheelchair during turning. At a representative maximum acceleration, the reactive torque spanned the range of 11.7 to 15.0 N-m across the wheelchair configurations. At higher accelerations, these torques exceeded that required to overcome caster scrub during turning. These results indicate that a wheelchair's rotational inertia can significantly influence the torque required during turning and that this influence will affect active users who turn at higher speeds. Categorizing wheelchairs using both mass and rotational inertia would better represent differences in effort during wheelchair maneuvers.

  13. A study of weld quality in ultrasonic spot welding of similar and dissimilar metals

    Science.gov (United States)

    Al-Sarraf, Z.; Lucas, M.

    2012-08-01

    Several difficulties are faced in joining thinner sheets of similar and dissimilar materials from fusion welding processes such as resistance welding and laser welding. Ultrasonic metal welding overcomes many of these difficulties by using high frequency vibration and applied pressure to create a solid-state weld. Ultrasonic metal welding is an effective technique in joining small components, such as in wire bonding, but is also capable of joining thicker sheet, depending on the control of welding conditions. This study presents the design, characterisation and test of a lateral-drive ultrasonic metal welding device. The ultrasonic welding horn is modelled using finite element analysis and its vibration behaviour is characterised experimentally to ensure ultrasonic energy is delivered to the weld coupon. The welding stack and fixtures are then designed and mounted on a test machine to allow a series of experiments to be conducted for various welding and ultrasonic parameters. Weld strength is subsequently analysed using tensile-shear tests. Control of the vibration amplitude profile through the weld cycle is used to enhance weld strength and quality, providing an opportunity to reduce part marking. Optical microscopic examination and scanning electron microscopy (SEM) were employed to investigate the weld quality. The results show how the weld quality is particularly sensitive to the combination of clamping force and vibration amplitude of the welding tip.

  14. A method of initial welding position guiding for arc welding robot based on visual servo control

    Institute of Scientific and Technical Information of China (English)

    郭振民; 陈善本; 邱涛; 吴林

    2003-01-01

    In order to solve the visual guiding task of initial welding position for arc welding robot, this paper presents a practice-prone image-based visual servo control strategy without calibration, and we perform validating experiments on a nine-DOF arc welding robot system. Experimental results illustrate presented method has the function to fulfill the task of welding robot initial positioning with certain anti-jamming ability. This method provides a basis for guiding welding gun to initial welding pose with real typical seam's image properties to replace flag block properties, and is a significant exploit to realize visual guiding of initial welding position and seam tracing in robot welding system.

  15. Is there an inertia due to the supersymmetry

    CERN Document Server

    Ter-Kazarian, Gagik

    2013-01-01

    We derive a standard Lorentz code (SLC) of motion by exploring rigid double transformations of, so-called, 'master space-induced' supersymmetry (MS-SUSY), subject to certain rules. The renormalizable and actually finite flat-space field theories with $N_{max}=4$ supersymmetries in four dimensions, if only such symmetries are fundamental to nature, yield the possible 'extension of Lorentz code' (ELC), at which the SLC violating new physics appears. In the framework of local MS-SUSY, we address the inertial effects. We argue that a space-time deformation of MS is the origin of inertia effects that can be observed by us. We go beyond the hypothesis of locality. This allows to improve the relevant geometrical structures referred to the noninertial frame in Minkowski space for an arbitrary velocities and characteristic acceleration lengths. This framework furnishes justification for the introduction of the 'weak' principle of equivalence, i.e., the 'universality of free fall'. The implications of the inertia effec...

  16. Thermal inertia mapping - A promising new tool for mineral exploration

    Science.gov (United States)

    Short, N. M.

    1983-01-01

    The Heat Capacity Mapping Mission (HCMM) is a NASA-sponsored program designed to acquire day visible and day and night thermal IR imagery from a satellite launched on April 26, 1978 into a near polar orbit at 620 km altitude. The data are used to produce temperature difference (12 or 36 hour interval) and apparent thermal inertia (ATI) images or numerical data sets for selected areas within much of North America, Europe, North Africa, and Australia. These data are being applied to rock type discrimination, soil moisture detection, assessment of vegetation states, thermal current monitoring in water bodies, urban heat island analysis and other multidisciplinary studies. Key geological results include (1) groups of dissimilar rock materials and some individual rock types can be separated and sometimes identified by their satellite-determined thermal inertias (dependent on their albedos, densities, and conductivities), (2) large lineaments (including some faults) are often recognized by their thermal signatures (may relate to moisture content and/or reduced bulk density), and (3) visually striking expressions of geomorphic units (types) at a regional scale are especially enhanced in the night IR imagery.

  17. Electromagnetic inertia, reactive energy and energy flow velocity

    Energy Technology Data Exchange (ETDEWEB)

    Kaiser, Gerald, E-mail: kaiser@wavelets.com [Center for Signals and Waves, Austin, TX (United States)

    2011-08-26

    In a recent paper titled 'Coherent electromagnetic wavelets and their twisting null congruences', I defined the local inertia density I(x,t), reactive energy density R(x,t) and energy flow velocity v(x,t) of an electromagnetic field. These are the field equivalents of the mass, rest energy and velocity of a relativistic particle. Thus, R=Ic{sup 2} is Lorentz-invariant and |v|{<=}c, with equality if and only if R=0. The exceptional fields with |v|=c were called coherent because their energy moves in complete harmony with the field, leaving no inertia or reactive energy behind. Generic electromagnetic fields become coherent only in the far zone. Elsewhere, their energy flows at speeds v(x,t)

  18. Laser welding of fused quartz

    Science.gov (United States)

    Piltch, Martin S.; Carpenter, Robert W.; Archer, III, McIlwaine

    2003-06-10

    Refractory materials, such as fused quartz plates and rods are welded using a heat source, such as a high power continuous wave carbon dioxide laser. The radiation is optimized through a process of varying the power, the focus, and the feed rates of the laser such that full penetration welds may be accomplished. The process of optimization varies the characteristic wavelengths of the laser until the radiation is almost completely absorbed by the refractory material, thereby leading to a very rapid heating of the material to the melting point. This optimization naturally occurs when a carbon dioxide laser is used to weld quartz. As such this method of quartz welding creates a minimum sized heat-affected zone. Furthermore, the welding apparatus and process requires a ventilation system to carry away the silicon oxides that are produced during the welding process to avoid the deposition of the silicon oxides on the surface of the quartz plates or the contamination of the welds with the silicon oxides.

  19. 10,170 flawless welds

    CERN Multimedia

    Antonella Del Rosso

    2014-01-01

    The welding of tubes containing the principal current-carrying busbars in the LHC magnets was one of the main activities of the SMACC project. After a year of preparation and another of intense activity in the tunnel, the last weld was completed on Wednesday 14 May. Over 10,170 welds have been inspected and not a single fault has been found.    The welder (above) creates the weld using an orbital welding machine (below) specifically designed for CERN. Each of the eight sectors of the LHC contains around 210 interconnects between the superconducting magnets. Consolidating these interconnections was the SMACC project’s primary objective. One of the last jobs before closing the interconnects is the welding of the M lines: each has a 104 mm diameter and a radial clearance of just 45 mm. In total: 10,170 welds carried out in a single year of activities. A true challenge, which was carried out by a team of 30 highly specialised welders, working under the supervision o...

  20. Pulse shaping effects on weld porosity in laser beam spot welds : contrast of long- & short- pulse welds.

    Energy Technology Data Exchange (ETDEWEB)

    Ellison, Chad M. (Honeywell FM& T, Kansas City, MO); Perricone, Matthew J. (R.J. Lee Group, Inc., Monroeville, PA); Faraone, Kevin M. (BWX Technologies, Inc., Lynchburg, VA); Norris, Jerome T.

    2007-10-01

    Weld porosity is being investigated for long-pulse spot welds produced by high power continuous output lasers. Short-pulse spot welds (made with a pulsed laser system) are also being studied but to a much small extent. Given that weld area of a spot weld is commensurate with weld strength, the loss of weld area due to an undefined or unexpected pore results in undefined or unexpected loss in strength. For this reason, a better understanding of spot weld porosity is sought. Long-pulse spot welds are defined and limited by the slow shutter speed of most high output power continuous lasers. Continuous lasers typically ramp up to a simmer power before reaching the high power needed to produce the desired weld. A post-pulse ramp down time is usually present as well. The result is a pulse length tenths of a second long as oppose to the typical millisecond regime of the short-pulse pulsed laser. This study will employ a Lumonics JK802 Nd:YAG laser with Super Modulation pulse shaping capability and a Lasag SLS C16 40 W pulsed Nd:YAG laser. Pulse shaping will include square wave modulation of various peak powers for long-pulse welds and square (or top hat) and constant ramp down pulses for short-pulse welds. Characterization of weld porosity will be performed for both pulse welding methods.

  1. Integration of high capacity materials into interdigitated mesostructured electrodes for high energy and high power density primary microbatteries

    Science.gov (United States)

    Pikul, James H.; Liu, Jinyun; Braun, Paul V.; King, William P.

    2016-05-01

    Microbatteries are increasingly important for powering electronic systems, however, the volumetric energy density of microbatteries lags behind that of conventional format batteries. This paper reports a primary microbattery with energy density 45.5 μWh cm-2 μm-1 and peak power 5300 μW cm-2 μm-1, enabled by the integration of large volume fractions of high capacity anode and cathode chemistry into porous micro-architectures. The interdigitated battery electrodes consist of a lithium metal anode and a mesoporous manganese oxide cathode. The key enabler of the high energy and power density is the integration of the high capacity manganese oxide conversion chemistry into a mesostructured high power interdigitated bicontinuous cathode architecture and an electrodeposited dense lithium metal anode. The resultant energy density is greater than previously reported three-dimensional microbatteries and is comparable to commercial conventional format lithium-based batteries.

  2. Residual stresses in welded plates

    Science.gov (United States)

    Bernstein, Edward L.

    1994-01-01

    The purpose of this project was to develop a simple model which could be used to study residual stress. The mechanism that results in residual stresses in the welding process starts with the deposition of molten weld metal which heats the immediately adjacent material. After solidification of weld material, normal thermal shrinkage is resisted by the adjacent, cooler material. When the thermal strain exceeds the elastic strain corresponding to the yield point stress, the stress level is limited by this value, which decreases with increasing temperature. Cooling then causes elastic unloading which is restrained by the adjoining material. Permanent plastic strain occurs, and tension is caused in the region immediately adjacent to the weld material. Compression arises in the metal farther from the weld in order to maintain overall static equilibrium. Subsequent repair welds may add to the level of residual stresses. The level of residual stress is related to the onset of fracture during welding. Thus, it is of great importance to be able to predict the level of residual stresses remaining after a weld procedure, and to determine the factors, such as weld speed, temperature, direction, and number of passes, which may affect the magnitude of remaining residual stress. It was hoped to use traditional analytical modeling techniques so that it would be easier to comprehend the effect of these variables on the resulting stress. This approach was chosen in place of finite element methods so as to facilitate the understanding of the physical processes. The accuracy of the results was checked with some existing experimental studies giving residual stress levels found from x-ray diffraction measurements.

  3. Lithographically encoded polymer microtaggant using high-capacity and error-correctable QR code for anti-counterfeiting of drugs.

    Science.gov (United States)

    Han, Sangkwon; Bae, Hyung Jong; Kim, Junhoi; Shin, Sunghwan; Choi, Sung-Eun; Lee, Sung Hoon; Kwon, Sunghoon; Park, Wook

    2012-11-20

    A QR-coded microtaggant for the anti-counterfeiting of drugs is proposed that can provide high capacity and error-correction capability. It is fabricated lithographically in a microfluidic channel with special consideration of the island patterns in the QR Code. The microtaggant is incorporated in the drug capsule ("on-dose authentication") and can be read by a simple smartphone QR Code reader application when removed from the capsule and washed free of drug.

  4. Laser welding and post weld treatment of modified 9Cr-1MoVNb steel.

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Z. (Nuclear Engineering Division)

    2012-04-03

    Laser welding and post weld laser treatment of modified 9Cr-1MoVNb steels (Grade P91) were performed in this preliminary study to investigate the feasibility of using laser welding process as a potential alternative to arc welding methods for solving the Type IV cracking problem in P91 steel welds. The mechanical and metallurgical testing of the pulsed Nd:YAG laser-welded samples shows the following conclusions: (1) both bead-on-plate and circumferential butt welds made by a pulsed Nd:YAG laser show good welds that are free of microcracks and porosity. The narrow heat affected zone has a homogeneous grain structure without conventional soft hardness zone where the Type IV cracking occurs in conventional arc welds. (2) The laser weld tests also show that the same laser welder has the potential to be used as a multi-function tool for weld surface remelting, glazing or post weld tempering to reduce the weld surface defects and to increase the cracking resistance and toughness of the welds. (3) The Vicker hardness of laser welds in the weld and heat affected zone was 420-500 HV with peak hardness in the HAZ compared to 240 HV of base metal. Post weld laser treatment was able to slightly reduce the peak hardness and smooth the hardness profile, but failed to bring the hardness down to below 300 HV due to insufficient time at temperature and too fast cooling rate after the time. Though optimal hardness of weld made by laser is to be determined for best weld strength, methods to achieve the post weld laser treatment temperature, time at the temperature and slow cooling rate need to be developed. (4) Mechanical testing of the laser weld and post weld laser treated samples need to be performed to evaluate the effects of laser post treatments such as surface remelting, glazing, re-hardening, or tempering on the strength of the welds.

  5. Novel Process Revolutionizes Welding Industry

    Science.gov (United States)

    2008-01-01

    Glenn Research Center, Delphi Corporation, and the Michigan Research Institute entered into a research project to study the use of Deformation Resistance Welding (DRW) in the construction and repair of stationary structures with multiple geometries and dissimilar materials, such as those NASA might use on the Moon or Mars. Traditional welding technologies are burdened by significant business and engineering challenges, including high costs of equipment and labor, heat-affected zones, limited automation, and inconsistent quality. DRW addresses each of those issues, while drastically reducing welding, manufacturing, and maintenance costs.

  6. Morphology control of ordered mesoporous carbons for high capacity lithium sulfur batteries

    Energy Technology Data Exchange (ETDEWEB)

    Schuster, Joerg David

    2011-06-07

    The focus of this thesis concerns the morphology control of ordered mesoporous carbon (OMC) materials. Ordered mesoporous carbons with diverse morphologies, that are thin films, fibers - embedded in anodic alumina membranes and free-standing - or spherical nanoparticles, have been successfully prepared by soft-templating procedures. The mechanisms of structure formation and processing were investigated with in-situ SAXS measurements and their application in high capacity lithium-sulfur batteries was successfully tested in cooperation with Guang He and Linda Nazar from the University of Waterloo in Canada. The Li-S batteries receive increasing attention due to their high theoretical energy density which is 3 to 5 times higher than from lithium-ion batteries. For this type of battery the specific pore volume is crucial for the content of the active component (sulfur) in the cathode and therefore correlates with the capacity and gravimetric energy density of the battery. At first, mesoporous thin films with 2D-hexagonal structure were obtained through organic-organic self-assembly of a preformed oligomeric resol precursor and the triblock copolymer template Pluronic P123. The formation of a condensed-wall material through thermopolymerization of the precursor oligomers resulted in mesostructured phenolic resin films. Subsequent decomposition of the surfactant and partial carbonization were achieved through thermal treatment in inert atmosphere. The films were crack-free with tunable homogenous thicknesses, and showed either 2D-hexagonal or lamellar mesostructure. An additional, yet unknown 3D-mesostructure was also found. In the second part, cubic and circular hexagonal mesoporous carbon phases in the confined environment of tubular anodic alumina membrane (AAM) pores were obtained by self-assembly of the mentioned resol precursor and the triblock copolymer templates Pluronic F127 or P123, respectively. Casting and solvent-evaporation were also followed by

  7. A High-Capacity Adenoviral Hybrid Vector System Utilizing the Hyperactive Sleeping Beauty Transposase SB100X for Enhanced Integration.

    Science.gov (United States)

    Boehme, Philip; Zhang, Wenli; Solanki, Manish; Ehrke-Schulz, Eric; Ehrhardt, Anja

    2016-07-19

    For efficient delivery of required genetic elements we utilized high-capacity adenoviral vectors in the past allowing high transgene capacities of up to 36 kb. Previously we explored the hyperactive Sleeping Beauty (SB) transposase (HSB5) for somatic integration from the high-capacity adenoviral vectors genome. To further improve this hybrid vector system we hypothesized that the previously described hyperactive SB transposase SB100X will result in significantly improved efficacies after transduction of target cells. Plasmid based delivery of the SB100X system revealed significantly increased integration efficiencies compared with the previously published hyperactive SB transposase HSB5. After optimizing experimental setups for high-capacity adenoviral vectors-based delivery of the SB100X system we observed up to eightfold and 100-fold increased integration efficiencies compared with the previously published hyperactive SB transposase HSB5 and the inactive transposase mSB, respectively. Furthermore, transposon copy numbers per cell were doubled with SB100X compared with HSB5 when using the identical multiplicity of infection. We believe that this improved hybrid vector system represents a valuable tool for achieving stabilized transgene expression in cycling cells and for treatment of numerous genetic disorders. Especially for in vivo approaches this improved adenoviral hybrid vector system will be advantageous because it may potentially allow reduction of the applied viral dose.

  8. Dual-Size Silicon Nanocrystal-Embedded SiO(x) Nanocomposite as a High-Capacity Lithium Storage Material.

    Science.gov (United States)

    Park, Eunjun; Yoo, Hyundong; Lee, Jaewoo; Park, Min-Sik; Kim, Young-Jun; Kim, Hansu

    2015-07-28

    SiOx-based materials attracted a great deal of attention as high-capacity Li(+) storage materials for lithium-ion batteries due to their high reversible capacity and good cycle performance. However, these materials still suffer from low initial Coulombic efficiency as well as high production cost, which are associated with the complicated synthesis process. Here, we propose a dual-size Si nanocrystal-embedded SiOx nanocomposite as a high-capacity Li(+) storage material prepared via cost-effective sol-gel reaction of triethoxysilane with commercially available Si nanoparticles. In the proposed nanocomposite, dual-size Si nanocrystals are incorporated into the amorphous SiOx matrix, providing a high capacity (1914 mAh g(-1)) with a notably improved initial efficiency (73.6%) and stable cycle performance over 100 cycles. The highly robust electrochemical and mechanical properties of the dual-size Si nanocrystal-embedded SiOx nanocomposite presented here are mainly attributed to its peculiar nanoarchitecture. This study represents one of the most promising routes for advancing SiOx-based Li(+) storage materials for practical use.

  9. Development of Welding Procedures for NPP Dissimilar Metal Weld

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jang Wook; Cho, Hong Seok; Lee, Dong Min; Park, Yu Deog; Choi, Sang Hoon [Korea Plant Service and Engineering Co., Seongnam (Korea, Republic of)

    2008-05-15

    Nuclear primary system consists of various materials according to the function. Recently, concern about the integrity on Dissimilar Metal Weld (DMW) which was made of inconel material such as alloy 600/82/182 has arisen from industry. Leak from hot leg nozzle weld at V.C Summer and axial cracks in hot leg nozzle welds at Ringhals 3 and 4 were took placed at the DMW zone, which is major degradation mechanism known as Primary Water Stress Corrosion Cracking (PWSCC). In order to ensure operational ability of nuclear power plants, it is necessary to obtain measures against unexpected risks. KPS has developed the DMW technology, Narrow Groove Welding (NGW) system and field implementation procedures for alloy 600 since March 2005.

  10. Materials participation in welded joints manufacturing

    Science.gov (United States)

    Ghenghea, L. D.

    2016-08-01

    Management of materials dilution to form a joint with higher features asked by complex metallic structures is a problem that took attention and efforts of welding processes researchers and this communication will give a little contribution presenting some scientific and experimental results of dilution processes studied by Welding Research Group from Iasi, Romania, TCM Department. Liquid state welding processes have a strong dependence related to dilution of base and filler materials, the most important are for automatic joining using welding. The paper presents a review of some scientific works already published and their contributions, results of dilution coefficient evaluation using weighing, graphics and software applied for shielded metal arc welding process. Paper results could be used for welders’ qualification, welding procedure specification and other welding processes researchers’ activities. The results of Welding Research Group from Iasi, Romania, TCM Department, show dilution coefficient values between 20-30 % of base material and 70-80 % of filler material for studied welding process.

  11. Independent effects of adding weight and inertia on balance during quiet standing

    Directory of Open Access Journals (Sweden)

    Costello Kerry

    2012-04-01

    Full Text Available Abstract Background Human balance during quiet standing is influenced by adding mass to the body with a backpack, with symmetrically-applied loads to the trunk, or with obesity. Adding mass to the body increases both the weight and inertia of the body, which theoretically could provide counteracting effects on body dynamics and balance. Understanding the independent effects of adding weight and inertia on balance may provide additional insight into human balance that could lead to novel advancements in balance training and rehabilitation. Therefore, the purpose of this study was to investigate the independent effects of adding weight and inertia on balance during quiet standing. Methods Sixteen normal-weight young adult participants stood as still as possible on a custom-built backboard apparatus under four experimental conditions: baseline, added inertia only, added weight only, and added inertia and weight. Results Adding inertia by itself had no measurable effect on center of pressure movement or backboard movement. Adding weight by itself increased center of pressure movement (indicated greater effort by the postural control system to stand as still as possible and backboard movement (indicating a poorer ability of the body to stand as still as possible. Adding inertia and weight at the same time increased center of pressure movement but did not increase backboard movement compared to the baseline condition. Conclusions Adding inertia and adding weight had different effects on balance. Adding inertia by itself had no effect on balance. Adding weight by itself had a negative effect on balance. When adding inertia and weight at the same time, the added inertia appeared to lessen (but did not eliminate the negative effect of adding weight on balance. These results improve our fundamental understanding of how added mass influences human balance.

  12. Effect of Welding Parameters on Dilution and Weld Bead Geometry in Cladding

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The effect of pulsed gas metal arc welding (GMAW) variables on the dilution and weld bead geometry in cladding X65 pipeline steel with 316L stainless steel was studied. Using a full factorial method, a series of experiments were carried out to know the effect of wire feed rate, welding speed, distance between gas nozzle and plate, and the vertical angle of welding on dilution and weld bead geometry. The findings indicate that the dilution of weld metal and its dimension i.e. width, height and depth increase with the feed rate, but the contact angle of the bead decreases first and then increases. Meantime, welding speed has an opposite effect except for dilution. There is an interaction effect between welding parameters at the contact angle. The results also show forehand welding or decreasing electrode extension decrease the angle of contact. Finally,a mathematical model is contrived to highlight the relationship between welding variables with dilution and weld bead geometry.

  13. Comparison between hybrid laser-MIG welding and MIG welding for the invar36 alloy

    Science.gov (United States)

    Zhan, Xiaohong; Li, Yubo; Ou, Wenmin; Yu, Fengyi; Chen, Jie; Wei, Yanhong

    2016-11-01

    The invar36 alloy is suitable to produce mold of composite materials structure because it has similar thermal expansion coefficient with composite materials. In the present paper, the MIG welding and laser-MIG hybrid welding methods are compared to get the more appropriate method to overcome the poor weldability of invar36 alloy. According to the analysis of the experimental and simulated results, it has been proved that the Gauss and cone combined heat source model can characterize the laser-MIG hybrid welding heat source well. The total welding time of MIG welding is 8 times that of hybrid laser-MIG welding. The welding material consumption of MIG welding is about 4 times that of hybrid laser-MIG welding. The stress and deformation simulation indicate that the peak value of deformation during MIG welding is 3 times larger than that of hybrid laser-MIG welding.

  14. Friction Stir Welding Technology: Adapting NASA's Retractable Pin Tool

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    In late 1991, The Welding Institute (TWI), a British research and technology organization, invented and patented a welding process named Friction Stir Welding (FSW). Friction Stir Welding is a highly significant advancement in aluminum welding technology that can produce stronger, lighter, and more efficient welds than any previous process.

  15. Research on image segmentation of weld seam of oil derrick welded by arc welding robot

    Institute of Scientific and Technical Information of China (English)

    Cai Guangyu; Cui Shilin; Wu Changlin

    2009-01-01

    This paper puts forward a new method of PCNN (pulse-coupled neural networks) image segmentation, in which the binary matrix of the ignition frequency matrix is employed, for the first time, to act as the final result of image segmentation. It gives the principles of PCNN parameter selection under the guidance of this process. The new method reduces the dependence of PCNN on parameters, improves the effect of image segmentation, and produces good results after being applied to image recognition of weld seam of oil derrick welded by arc welding robot.

  16. Explosive welding of undersea pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Stalker, A.W.

    1978-02-01

    The phenomenon of explosive welding has been known informally for many years. A number of investigations reported the occurerence of solid phase bonds as an incidental effect when using high explosives in association with adjacent metal surfaces and probably the earliest formal record was the observation by Carl in 1944 of a bond between two copper discs in contact with a detonator. In 1957 Philipchuk reported what is now recognized as an explosive weld between aluminium channel sections and a steel die when carrying out explosive forming trials. Since then a great deal of development work has resulted in explosive welding becoming a well established manufacturing technique, particularly in the fields of cladding and the joining of tube/tubeplates. In more recent years the process has been extended to the welding of large diameter line pipe materials.

  17. Welding Development W87 Baseline

    Energy Technology Data Exchange (ETDEWEB)

    A. Newman; G. Gibbs; G. K. Hicken

    1998-11-01

    This report covers the development activities used to qualify the Gas Tungsten Arc (FTA) girth weld and the resistance stem attachments on the W87 Base Line (W87BL). Design of experiments was used throughout the development activities.

  18. Thermomechanical Modelling of Resistance Welding

    DEFF Research Database (Denmark)

    Bay, Niels; Zhang, Wenqi

    2007-01-01

    The present paper describes a generic programme for analysis, optimization and development of resistance spot and projection welding. The programme includes an electrical model determining electric current and voltage distribution as well as heat generation, a thermal model calculating heat...

  19. Welding and Production Metallurgy Facility

    Data.gov (United States)

    Federal Laboratory Consortium — This 6000 square foot facility represents the only welding laboratory of its kind within DA. It is capable of conducting investigations associated with solid state...

  20. Weld bonding of stainless steel

    DEFF Research Database (Denmark)

    Santos, I. O.; Zhang, Wenqi; Goncalves, V.M.

    2004-01-01

    This paper presents a comprehensive theoretical and experimental investigation of the weld bonding process with the purpose of evaluating its relative performance in case of joining stainless steel parts, against alternative solutions based on structural adhesives or conventional spot...

  1. YAG laser welding with surface activating flux

    Institute of Scientific and Technical Information of China (English)

    樊丁; 张瑞华; 田中学; 中田一博; 牛尾诚夫

    2003-01-01

    YAG laser welding with surface activating flux has been investigated, and the influencing factors and mechanism are discussed. The results show that both surface activating flux and surface active element S have fantastic effects on the YAG laser weld shape, that is to obviously increase the weld penetration and D/W ratio in various welding conditions. The mechanism is thought to be the change of weld pool surface tension temperature coefficient, thus, the change of fluid flow pattern in weld pool due to the flux.

  2. Forming of aluminium alloy friction stir welds

    Science.gov (United States)

    Bruni, Carlo

    2016-10-01

    The present paper aims at investigating, through analytical models, numerical models and experiments, the effect of the warm deformation phase, realised with an in temperature upsetting, on the weld previously performed by friction stir lap welding on aluminium alloy blanks. The investigation allows to show the deformation zones after upsetting that determine the homogenisation of the weld section. The analytical model allows to relate the friction factor with the upsetting load. The presence on the weld of not elevated friction factor values determines the deformation and localisation levels very useful for the weld. Such methodology allows to improve the weld itself with the forming phase.

  3. Experimental study on activating welding for aluminum alloys

    Institute of Scientific and Technical Information of China (English)

    Huang Yong; Fan Ding

    2005-01-01

    TIG welding and EB welding for aluminum alloy 3003 were carried out to study the effects of activating flux on weld penetration of activating welding for aluminum alloys. SiO2 was used as the activating flux. It is found that, SiO2 can increase the weld penetration and decrease the weld width of FBTIG when the flux gap is small. For A-TIG welding and EB welding with focused mode, the weld penetrations and the weld widths increase simultaneously. SiO2 has little effect on the weld penetration and weld width of EB welding with defocused mode. It is believed that, change of surface tension temperature gradient is not the main mechanism of SiO2 improving weld penetration of activating welding for aluminum alloys.

  4. Laser based spot weld characterization

    Science.gov (United States)

    Jonietz, Florian; Myrach, Philipp; Rethmeier, Michael; Suwala, Hubert; Ziegler, Mathias

    2016-02-01

    Spot welding is one of the most important joining technologies, especially in the automotive industry. Hitherto, the quality of spot welded joints is tested mainly by random destructive tests. A nondestructive testing technique offers the benefit of cost reduction of the testing procedure and optimization of the fabrication process, because every joint could be examined. This would lead to a reduced number of spot welded joints, as redundancies could be avoided. In the procedure described here, the spot welded joint between two zinc-coated steel sheets (HX340LAD+Z100MB or HC340LA+ZE 50/50) is heated optically on one side. Laser radiation and flash light are used as heat sources. The melted zone, the so called "weld nugget" provides the mechanical stability of the connection, but also constitutes a thermal bridge between the sheets. Due to the better thermal contact, the spot welded joint reveals a thermal behavior different from the surrounding material, where the heat transfer between the two sheets is much lower. The difference in the transient thermal behavior is measured with time resolved thermography. Hence, the size of the thermal contact between the two sheets is determined, which is directly correlated to the size of the weld nugget, indicating the quality of the spot weld. The method performs well in transmission with laser radiation and flash light. With laser radiation, it works even in reflection geometry, thus offering the possibility of testing with just one-sided accessibility. By using heating with collimated laser radiation, not only contact-free, but also remote testing is feasible. A further convenience compared to similar thermographic approaches is the applicability on bare steel sheets without any optical coating for emissivity correction. For this purpose, a proper way of emissivity correction was established.

  5. Inertia and advance in the organic sector: food education in Denmark

    DEFF Research Database (Denmark)

    Dahl, Astrid; Kristensen, Niels Heine

    2005-01-01

    Dahl A, & Kristensen NH (2005): Inertia and advance in the organic sector: food education in Denmark. Chapter in Sociological Perspectives of Organic Agriculture. (Edt.: G. Holt and M. Reed). CABI, UK......Dahl A, & Kristensen NH (2005): Inertia and advance in the organic sector: food education in Denmark. Chapter in Sociological Perspectives of Organic Agriculture. (Edt.: G. Holt and M. Reed). CABI, UK...

  6. Measurement of Constant Acceleration of a Body: Moment of Inertia. Laboratory Manual.

    Science.gov (United States)

    Villamoran, E. P.

    This document provides a laboratory manual for an experiment whose objectives are: (1) measure the constant acceleration of a body; (2) calculate the moment of inertia for various symmetrical shape objects; and (3) use the moment of inertia to solve for the constant acceleration of the body. The paper includes a list of materials needed, theory,…

  7. An approximate method for solution to variable moment of inertia problems

    Science.gov (United States)

    Beans, E. W.

    1981-01-01

    An approximation method is presented for reducing a nonlinear differential equation (for the 'weather vaning' motion of a wind turbine) to an equivalent constant moment of inertia problem. The integrated average of the moment of inertia is determined. Cycle time was found to be the equivalent cycle time if the rotating speed is 4 times greater than the system's minimum natural frequency.

  8. Kinematic Moment of Inertia of e-e Rare Earths Nuclei

    OpenAIRE

    Kelabi, Mohamed E.

    2013-01-01

    The kinematic moment of inertia of the rare earth even-even nuclei was calculated using three parametric energy based expression. The plot of kinematic moment of inertia versus nuclear spin shows a better sensitivity to back bending than energy plot.

  9. Calculation of the inertia tensor and center of gravity of complex bodies

    Science.gov (United States)

    Howard, L. A.

    1970-01-01

    Inertia tensor is calculated for each component part of a body about its own principal axes, and then with respect to the body's reference axes /rotation/. All parts are then combined to calculate the center of gravity and inertia tensor of the body.

  10. Thermal inertia of eclipsing binary asteroids : the role of component shape

    NARCIS (Netherlands)

    Mueller, Michael; van de Weijgaert, Marlies

    2015-01-01

    Thermal inertia controls the temperature distribution on asteroid surfaces. This is of crucial importance to the Yarkovsky effect and for the planning of spacecraft operations on or near the surface. Additionally, thermal inertia is a sensitive indicator for regolith structure.A uniquely direct way

  11. Thermal inertia of eclipsing binary asteroids: the role of component shape

    NARCIS (Netherlands)

    Mueller, Michael; van de Weijgaert, Marlies

    2015-01-01

    Thermal inertia controls the temperature distribution on asteroid surfaces. This is of crucial importance to the Yarkovsky effect and for the planning of spacecraft operations on or near the surface. Additionally, thermal inertia is a sensitive indicator for regolith structure.A uniquely direct way

  12. Inertia in travel choice: The role of risk aversion and learning

    NARCIS (Netherlands)

    Chorus, C.; Dellaert, B.

    2009-01-01

    This paper contributes to literature by showing how travellers that make normatively rational choices exhibit inertia during a series of risky choices. Our analyses complement other studies that conceive inertia as the result of boundedly rational or even non-deliberate, habitual decision-making. We

  13. Kπ=1+ pairing interaction and moments of inertia of superdeformed rotational bands in atomic nuclei

    Science.gov (United States)

    Hamamoto, I.; Nazarewicz, W.

    1994-05-01

    The effect of the pairing interaction coming from the rotationally induced Kπ=1+ pair-density on the nuclear moments of inertia is studied. It is pointed out that, contrary to the situation at normal deformations, the inclusion of the Kπ=1+ pairing may appreciably modify the frequency dependence of the moments of inertia at superdeformed shapes.

  14. Giant pulsar glitches and the inertia of neutron star crusts

    Science.gov (United States)

    Delsate, T.; Chamel, N.; Gürlebeck, N.; Fantina, A. F.; Pearson, J. M.; Ducoin, C.

    2016-07-01

    Giant pulsar frequency glitches as detected in the emblematic Vela pulsar have long been thought to be the manifestation of a neutron superfluid permeating the inner crust of a neutron star. However, this superfluid has been recently found to be entrained by the crust, and as a consequence it does not carry enough angular momentum to explain giant glitches. The extent to which pulsar-timing observations can be reconciled with the standard vortex-mediated glitch theory is studied considering the current uncertainties on dense-matter properties. To this end, the crustal moment of inertia of glitching pulsars is calculated employing a series of different unified dense-matter equations of state.

  15. An improved value of the lunar moment of inertia

    Science.gov (United States)

    Blackshear, W. T.; Gapcynski, J. P.

    1977-01-01

    The lunar gravitational research reported on by Gapcynski et al., (1975) has been extended to include an additional 600 days of the time variation of ascending node for the Explorer 49 spacecraft. Analysis of these additional data resulted in an improved value of the second-degree zonal harmonic coefficient C(20) = (-2.0219 equal to 0.0091) times 10 to the minus 4. This value of C(20) used in conjunction with the parameters beta equal to libration (631.27 + or - 0.03) times 10 to the minus 6 and gamma to (227.7 + or - 0.7) times 10 to the minus 6 yields a more accurate definition of the lunar moment of inertia ratio equal to 0.391 + or - 0.002.

  16. An improved lunar moment of inertia determination - A proposed strategy

    Science.gov (United States)

    Ananda, M. P.; Ferrari, A. J.; Sjogren, W. L.

    1977-01-01

    A strategy for determining an improved lunar moment of inertia is proposed. An improved uncertainty in the lunar inhomogeneity parameter could reduce the core density error from 4.20 gr/cu cm to 0.1 gm/cu cm for the case of a lunar density model having a 300 km core radius. The current error of 0.0025 for the lunar inhomogeneity parameter is mostly due to the uncertainties in the C20 and C22 gravity harmonics. An optimum reduction strategy for obtaining an order of magnitude improvement in the gravity estimates is based on covariance analyses of Doppler data. The long-arc reduction method is shown to provide better results than the short-arc technique, and the use of an orbit with a 7000 km semimajor axis along with certain terms of up to degree and order eight is recommended.

  17. The earth's equatorial principal axes and moments of inertia

    Science.gov (United States)

    Liu, H. S.; Chao, B. F.

    1991-01-01

    The earth's equatorial principal moments of inertia are given as A and B, where A is less than B, and the corresponding principal axes are given as a and b. Explicit formulas are derived for determining the orientation of a and b axes and the difference B - A using C(22) and S(22), the two gravitational harmonic coefficients of degree 2 and order 2. For the earth, the a axis lies along the (14.93 deg W, 165.07 deg E) diameter, and the b axis lies perpendicular to it along the (75.07 deg E, 104.93 deg W) diameter. The difference B - A is 7.260 x 10 to the -6th MR2. These quantities for other planets are contrasted, and geophysical implications are discussed.

  18. Gravity field, shape, and moment of inertia of Titan.

    Science.gov (United States)

    Iess, Luciano; Rappaport, Nicole J; Jacobson, Robert A; Racioppa, Paolo; Stevenson, David J; Tortora, Paolo; Armstrong, John W; Asmar, Sami W

    2010-03-12

    Precise radio tracking of the spacecraft Cassini has provided a determination of Titan's mass and gravity harmonics to degree 3. The quadrupole field is consistent with a hydrostatically relaxed body shaped by tidal and rotational effects. The inferred moment of inertia factor is about 0.34, implying incomplete differentiation, either in the sense of imperfect separation of rock from ice or a core in which a large amount of water remains chemically bound in silicates. The equilibrium figure is a triaxial ellipsoid whose semi-axes a, b, and c differ by 410 meters (a-c) and 103 meters (b-c). The nonhydrostatic geoid height variations (up to 19 meters) are small compared to the observed topographic anomalies of hundreds of meters, suggesting a high degree of compensation appropriate to a body that has warm ice at depth.

  19. The Problem of Inertia in a Friedmann Universe

    Science.gov (United States)

    Kazanas, Demosthenes

    2012-01-01

    In this talk I will discuss the origin of inertia in a curved spacetime, particularly the spatially flat, open and closed Friedmann universes. This is done using Sciama's law of inertial induction, which is based on Mach's principle, and expresses the analogy between the retarded far fields of electrodynamics and those of gravitation. After obtaining covariant expressions for electromagnetic fields due to an accelerating point charge in Friedmann models, we adopt Sciama's law to obtain the inertial force on an accelerating mass $m$ by integrating over the contributions from all the matter in the universe. The resulting inertial force has the form $F = -kma$ where the constant $k < 1 $ depends on the choice of the cosmological parameters such as $\\Omega_{M},\\ \\Omega_{\\Lambda}, $ and $\\Omega_{R}$. The values of $k$ obtained suggest that inertial contribution from dark matter can be the source for the missing part of the inertial force.

  20. Kidney organ donation: developing family practice initiatives to reverse inertia

    Directory of Open Access Journals (Sweden)

    Morgan Myfanwy

    2010-05-01

    Full Text Available Abstract Background Kidney transplantation is associated with greater long term survival rates and improved quality of life compared with dialysis. Continuous growth in the number of patients with kidney failure has not been matched by an increase in the availability of kidneys for transplantation. This leads to long waiting lists, higher treatment costs and negative health outcomes. Discussion Misunderstandings, public uncertainty and issues of trust in the medical system, that limit willingness to be registered as a potential donor, could be addressed by community dissemination of information and new family practice initiatives that respond to individuals' personal beliefs and concerns regarding organ donation and transplantation. Summary Tackling both personal and public inertia on organ donation is important for any community oriented kidney donation campaign.

  1. Growth and dispersal with inertia: Hyperbolic reaction-transport systems

    Science.gov (United States)

    Méndez, Vicenç; Campos, Daniel; Horsthemke, Werner

    2014-10-01

    We investigate the behavior of five hyperbolic reaction-diffusion equations most commonly employed to describe systems of interacting organisms or reacting particles where dispersal displays inertia. We first discuss the macroscopic or mesoscopic foundation, or lack thereof, of these reaction-transport equations. This is followed by an analysis of the temporal evolution of spatially uniform states. In particular, we determine the uniform steady states of the reaction-transport systems and their stability properties. We then address the spatiotemporal behavior of pure death processes. We end with a unified treatment of the front speed for hyperbolic reaction-diffusion equations with Kolmogorov-Petrosvskii-Piskunov kinetics. In particular, we obtain an exact expression for the front speed of a general class of reaction correlated random walk systems. Our results establish that three out of the five hyperbolic reaction-transport equations provide physically acceptable models of biological and chemical systems.

  2. Towards an interpretation of MOND as a modification of inertia

    CERN Document Server

    Namouni, Fathi

    2015-01-01

    We explore the possibility that Milgrom's Modified Newtonian Dynamics (MOND) is a manifestation of the modification of inertia at small accelerations. Consistent with the Tully-Fisher relation, dynamics in the small acceleration domain may originate from a quartic (cubic) velocity-dependence of energy (momentum) whereas gravitational potentials remain linear with respect to mass. The natural framework for this interpretation is Finsler geometry. The simplest static isotropic Finsler metric of a gravitating mass that incorporates the Tully-Fisher relation at small acceleration is associated with a spacetime interval that is either a homogeneous quartic root of polynomials of local displacements or a simple root of a rational fraction thereof. We determine the low energy gravitational equation and find that Finsler spacetimes that produce a Tully-Fisher relation require that the gravitational potential be modified. For an isolated mass, Newton's potential $Mr^{-1}$ is replaced by $Ma_0\\log (r/r_0)$ where $a_0$ ...

  3. On the electromagnetic origin of inertia and inertial mass

    CERN Document Server

    Martins, Alexandre A

    2008-01-01

    We address the problem of inertial property of matter through analysis of the motion of an extended charged particle. Our approach is based on the continuity equation for momentum (Newton's second law) taking due account of the vector potential and its convective derivative. We obtain a development in terms of retarded potentials allowing an intuitive physical interpretation of its main terms. The inertial property of matter is then discussed in terms of a kind of induction law related to the extended charged particle's own vector potential. Moreover, it is obtained a force term that represents a drag force acting on the charged particle when in motion relatively to its own vector potential field lines. The time rate of variation of the particle's vector potential leads to the acceleration inertia reaction force, equivalent to the Schott term responsible for the source of the radiation field. We also show that the velocity dependent term of the particle's vector potential is connected with the relativistic in...

  4. Laser Welding in Electronic Packaging

    Science.gov (United States)

    2000-01-01

    The laser has proven its worth in numerous high reliability electronic packaging applications ranging from medical to missile electronics. In particular, the pulsed YAG laser is an extremely flexible and versatile too] capable of hermetically sealing microelectronics packages containing sensitive components without damaging them. This paper presents an overview of details that must be considered for successful use of laser welding when addressing electronic package sealing. These include; metallurgical considerations such as alloy and plating selection, weld joint configuration, design of optics, use of protective gases and control of thermal distortions. The primary limitations on use of laser welding electronic for packaging applications are economic ones. The laser itself is a relatively costly device when compared to competing welding equipment. Further, the cost of consumables and repairs can be significant. These facts have relegated laser welding to use only where it presents a distinct quality or reliability advantages over other techniques of electronic package sealing. Because of the unique noncontact and low heat inputs characteristics of laser welding, it is an ideal candidate for sealing electronic packages containing MEMS devices (microelectromechanical systems). This paper addresses how the unique advantages of the pulsed YAG laser can be used to simplify MEMS packaging and deliver a product of improved quality.

  5. Coalescence-induced jumping of droplet: Inertia and viscosity effects

    Science.gov (United States)

    Farokhirad, Samaneh; Morris, Jeffrey F.; Lee, Taehun

    2015-10-01

    The problem of coalescence-induced self-propelled jumping of droplet is studied using three-dimensional numerical simulation. The focus is on the effect of inertia and in particular the effect of air density on the behavior of the merged droplet during jumping. A lattice Boltzmann method is used for two identical, static micro-droplets coalescing on a homogeneous substrate with contact angle ranging from 0∘ to 180∘. The results reveal that the effect of air density is significant on detachment of the merged droplet from the substrate at the later stage of the jumping process; the larger the air density, the larger the jumping height of the droplet. Analysis of streamlines and vorticity contours is performed for density ratios ranging from 60 to 800. These show a generation of vortical structures inside and around the droplet. The intensity of these structures gets weaker after droplet departure as the air inertia is decreased. The results are also presented in terms of phase diagrams of the merged droplet jumping for different Ohnesorge numbers (Oh) and surface wettabilities for both small and large density ratios. The critical value of contact angle where the merged droplet jumps away from the substrate is independent of density ratio and has a value around 150∘. However, the critical value of Oh depends on both density ratio and wettability of the surface for contact angles greater than 150∘. In this range of contact angle, the diagrams show two distinct dynamical regimes for different density ratios, namely, inertial and viscous regimes.

  6. Emotional inertia prospectively predicts the onset of depressive disorder in adolescence.

    Science.gov (United States)

    Kuppens, Peter; Sheeber, Lisa B; Yap, Marie B H; Whittle, Sarah; Simmons, Julian G; Allen, Nicholas B

    2012-04-01

    Emotional inertia refers to the degree to which a person's current emotional state is predicted by their prior emotional state, reflecting how much it carries over from one moment to the next. Recently, in a cross-sectional study, we showed that high inertia is an important characteristic of the emotion dynamics observed in psychological maladjustment such as depression. In the present study, we examined whether emotional inertia prospectively predicts the onset of first-episode depression during adolescence. Emotional inertia was assessed in a sample of early adolescents (N = 165) based on second-to-second behavioral coding of videotaped naturalistic interactions with a parent. Greater inertia of both negative and positive emotional behaviors predicted the emergence of clinical depression 2.5 years later. The implications of these findings for the understanding of the etiology and early detection of depression are discussed. (PsycINFO Database Record (c) 2012 APA, all rights reserved).

  7. The area moment of inertia of the tibia: a risk factor for stress fractures.

    Science.gov (United States)

    Milgrom, C; Giladi, M; Simkin, A; Rand, N; Kedem, R; Kashtan, H; Stein, M; Gomori, M

    1989-01-01

    In a prospective study of stress fractures among Israeli infantry recruits, the area moment of inertia of the tibia was found to have a statistically significant correlation with the incidence of tibial, femoral and total stress fractures. Recruits with "low" area moments of inertia of the tibia were found to have higher stress fracture morbidity than those with "high" area moments of inertia. The best correlation was obtained when the area moment of inertia was calculated about the AP axis of bending at a cross-sectional level corresponding to the narrowest tibial width on lateral X-rays, a point which is at the distal quarter of the tibia. This finding indicates that bending forces about the approximate AP axis are an important causal factor for tibial and many other stress fractures. The bone's bending strength, or ability to resist bending moments, as measured by the area moment of inertia, helps determine risk to stress fracture.

  8. ANALYSIS OF METHOD FOR DETERMINING AZIMUTH OF PRINCIPAL AXIS OF INERTIA BASED ON DYNAMIC BALANCE MEASUREMENT

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jun; GUAN Yingzi; QI Naiming

    2006-01-01

    The dynamic balance quality of a rotating object is an important factor to maintain the stability and accuracy for motion. The azimuth of the principal axis of inertia is a major sign of dynamic balance. A usual method is measuring moment of inertia matrix relative to some base coordinates on a rotary inertia machine so as to calculate the azimuth of principal axis of inertia. By using the measured unbalance results on the two trimmed planes on a vertical hard bearing double-plane dynamic balancing machine, the dimension and direction of couple unbalance can be found. An azimuth angle formula for the principal axis of inertia is derived and is solved by using unbalance quantities. The experiments indicate that method based on dynamic balancing measurement is proved rational and effective and has a fine precision.

  9. An experimental method for measuring the moment of inertia of an electric power wheelchair.

    Science.gov (United States)

    Wang, Hongwu; Grindle, Garrett G; Connor, Samuel; Cooper, Rory A

    2007-01-01

    This study describe an experiment measuring the moment of inertia of an electric powered wheelchair (EPW) using a torsional pendulum method. Inertia of the wheelchair is an important factor for control, which is a key issue in wheelchair driving. The experimental test platform consisted of a bottom circular wood plate, an upper metal plate, and four ropes. Materials with known moments of inertia such as the metal disk and cylinder were used to test the accuracy of the system. The EPW used in the experiment was Invacare G3 Torque SP Storm Series. The measured result of the moment inertia of the wheelchair was 5.2280 kg.m(2) and the errors of the system are less than 10% even when the object is only 25lbs. The results are consistent when compared with other approximate methods. In addition, the experimental method could be used to measure the moment of inertia of manual wheelchairs and other irregular objects.

  10. Model-Independent Inference of Neutron Star Radii from Moment of Inertia Measurements

    CERN Document Server

    Raithel, Carolyn A; Psaltis, Dimitrios

    2016-01-01

    A precise moment of inertia measurement for PSR J0737-3039A in the double pulsar system is expected within the next five years. We present here a new method of mapping the anticipated measurement of the moment of inertia directly into the neutron star structure. We determine the maximum and minimum values possible for the moment of inertia of a neutron star of a given radius based on physical stability arguments, assuming knowledge of the equation of state only at densities below the nuclear saturation density. If the equation of state is trusted up to the nuclear saturation density, we find that a measurement of the moment of inertia will place absolute bounds on the radius of PSR J0737-3039A to within $\\pm$1 km. The resulting combination of moment of inertia, mass, and radius measurements for a single source will allow for new, stringent constraints on the dense-matter equation of state.

  11. Thermal inertia mapping of Mars from 60 deg S to 60 deg N

    Science.gov (United States)

    Palluconi, F. D.; Kieffer, H. H.

    1981-01-01

    The considered region comprises 81% of the surface of Mars. Thermal inertia I is a composite surface property, which is equal to the square root of the product of three factors, including the thermal conductivity, the density, and the specific heat. I is the sole thermal parameter which governs the temperature variation of a periodically heated homogeneous surface, and, as such, is the prime intermediary between remote temperature observations and their geologic interpretation. The values for the thermal inertia found imply particulate surface materials. The variation in Martian surface thermal conductivity is about two orders of magnitude. Three large regions of low-inertia material are defined. Low-inertia material always possesses high albedo. There is a general tendency for higher-thermal-inertia surfaces to be darker but exceptions occur which may be related to a thin mantling of light dust or bonding of light material.

  12. Totally confined explosive welding

    Science.gov (United States)

    Bement, L. J. (Inventor)

    1978-01-01

    The undesirable by-products of explosive welding are confined and the association noise is reduced by the use of a simple enclosure into which the explosive is placed and in which the explosion occurs. An infrangible enclosure is removably attached to one of the members to be bonded at the point directly opposite the bond area. An explosive is completely confined within the enclosure at a point in close proximity to the member to be bonded and a detonating means is attached to the explosive. The balance of the enclosure, not occupied by explosive, is filled with a shaped material which directs the explosive pressure toward the bond area. A detonator adaptor controls the expansion of the enclosure by the explosive force so that the enclosure at no point experiences a discontinuity in expansion which causes rupture. The use of the technique is practical in the restricted area of a space station.

  13. Welding of Prosthetic Alloys

    Directory of Open Access Journals (Sweden)

    Wojciechowska M.

    2015-04-01

    Full Text Available This paper presents the techniques of joining metal denture elements, used in prosthetic dentistry: the traditional soldering technique with a gas burner and a new technique of welding with a laser beam; the aim of the study was to make a comparative assessment of the quality of the joints in view of the possibility of applying them in prosthetic structures. Fractographic examinations were conducted along with tensile strength and impact strength tests, and the quality of the joints was assessed compared to the solid metal. The experiments have shown that the metal elements used to make dentures, joined by the technique which employs a laser beam, have better strength properties than those achieved with a gas burner.

  14. Ship construction and welding

    CERN Document Server

    Mandal, Nisith R

    2017-01-01

    This book addresses various aspects of ship construction, from ship types and construction materials, to welding technologies and accuracy control. The contents of the book are logically organized and divided into twenty-one chapters. The book covers structural arrangement with longitudinal and transverse framing systems based on the service load, and explains basic structural elements like hatch side girders, hatch end beams, stringers, etc. along with structural subassemblies like floors, bulkheads, inner bottom, decks and shells. It presents in detail double bottom construction, wing tanks & duct keels, fore & aft end structures, etc., together with necessary illustrations. The midship sections of various ship types are introduced, together with structural continuity and alignment in ship structures. With regard to construction materials, the book discusses steel, aluminum alloys and fiber reinforced composites. Various methods of steel material preparation are discussed, and plate cutting and form...

  15. NASA welding assessment program

    Science.gov (United States)

    Stofel, E. J.

    1984-01-01

    A long duration test was conducted for comparing various methods of attaching electrical interconnects to solar cells for near Earth orbit spacecraft. Representative solar array modules were thermally cycled for 36,000 cycles between -80 and +80 C. The environmental stress of more than 6 years on a near Earth spacecraft as it cycles in and out of the earth's shadow was simulated. Evaluations of the integrity of these modules were made by visual and by electrical examinations before starting the cycling and then at periodic intervals during the cycling tests. Modules included examples of parallel gap and of ultrasonic welding, as well as soldering. The materials and fabrication processes are state of the art, suitable for forming large solar arrays of spacecraft quality. The modules survived this extensive cycling without detectable degradation in their ability to generate power under sunlight illumination.

  16. A study of processes for welding pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Weston, J. (ed.)

    1991-07-01

    A review was made of exisiting and potential processes for welding pipelines: fusion welding (arc, electron beam, laser, thermit) and forge welding (friction, flash, magnetically impelled arc butt, upset butt, explosive, shielded active gas, gas pressure). Consideration of J-lay operations gave indications that were reflections of the status of the processes in terms of normal land and offshore S-lay operation: forge welding processes, although having promise require considerable development; fusion welding processes offer several possibilities (mechanized GMA welding likely to be used in 1991-2); laser welding requires development in all pipeline areas: a production machine for electron beam welding will involve high costs. Nondestructive testing techniques are also reviewed. Demand for faster quality assessment is being addressed by speeding radiographic film processing and through the development of real time radiography and automatic ultrasonic testing. Conclusions on most likely future process developments are: SMAW with cellulosic electrodes is best for tie-ins, short pip runs; SMAW continues to be important for small-diameter lines, although mechanized GMA could be used, along with mechanical joining, MIAB, radial fraction, and flash butt; mechanized GMA welding is likely to predominate for large diameter lines and probably will be used for the first J-lay line (other techniques could be used too); and welding of piping for station facilities involves both shop welding of sub-assemblies and on-site welding of pipe and sub-assemblies to each other (site welding uses both SMAW and GMAW). Figs, tabs.

  17. Effect of Welding Methods on the Structure and Mechanical Properties of Welded Joints of Screw Piles

    Science.gov (United States)

    Golikov, N. I.; Sidorov, M. M.; Stepanova, K. V.

    2016-11-01

    Mechanical properties and characteristics of the structure of welded joints of screw piles are studied. It is shown that cast tips from steel 25L do not meet the performance specifications for operation in the Northern climatic zone. Quality welded joints of screw piles can be obtained by semiautomatic welding in an environment of CO2 with Sv-08G2S welding wire.

  18. Development of technique for laser welding of biological tissues using laser welding device and nanocomposite solder.

    Science.gov (United States)

    Gerasimenko, A; Ichcitidze, L; Podgaetsky, V; Ryabkin, D; Pyankov, E; Saveliev, M; Selishchev, S

    2015-08-01

    The laser device for welding of biological tissues has been developed involving quality control and temperature stabilization of weld seam. Laser nanocomposite solder applied onto a wound to be weld has been used. Physicochemical properties of the nanocomposite solder have been elucidated. The nature of the tissue-organizing nanoscaffold has been analyzed at the site of biotissue welding.

  19. ALGORITHM AND IMPLEMENTATION OF AUTO-SEARCHING WELD LINE FOR WELDING MOBILE ROBOT

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ke; L(U) Xueqin; WU Yixiong; LOU Songnian

    2006-01-01

    An algorithm of auto-searching weld line for welding mobile robot is presented.Auto-searching weld line is that the robot can automatically recognize a weld groove according to the characteristics of the weld groove before welding, and then adjust itself posture to the desired status preparing for welding, namely, it is a process that the robot autonomously aligns itself to the center of welding seam. Firstly, the configuration of welding mobile robot with the function of auto-searching weld line is introduced, then the algorithm and implementation of auto-searching weld line are presented on the basis of kinematics model of the robot, at last trajectory planning among auto-searching weld line is investigated in detail. The experiment result shows that the developed welding mobile robot can successfully implement the task of auto-searching weld line before welding, tracking error precision can be controlled to approximate ± 1.5 mm, and satisfy the requirement of practical welding project.

  20. EMAT weld inspection and weld machine diagnostic system for continuous coil processing lines

    Science.gov (United States)

    Latham, Wayne M.; MacLauchlan, Daniel T.; Geier, Dan P.; Lang, Dennis D.

    1996-11-01

    Weld breaks of steel coil during cold rolling and continuous pickling operations are a significant source of lost productivity and product yield. Babcock and Wilcox Innerspec Technologies has developed a weld process control system which monitors the key variables of the welding process and determines the quality of the welds generated by flash butt welding equipment. This system is known as the Temate 2000 Automated Flash Butt Weld Inspection and Weld Machine Diagnostic System. The Temate 2000 system utilizes electro- magnetic acoustic transducer (EMAT) technology as the basis for performing on-line, real-time, nondestructive weld quality evaluation. This technique accurately detects voids, laps, misalignment and over/under trim conditions in the weld. Results of the EMAT weld inspection are immediately presented to the weld machine operator for disposition. Welding process variables such as voltage, current, platen movements and upset pressures are monitored and collected with the high speed data acquisition system. This data is processed and presented in real-time display to indicate useful welding process information such as platen crabbing, upset force, peak upset current, and many others. Alarming for each variable is provided and allows detailed maintenance reports and summary information to be generated. All weld quality and process parameter data are stored, traceable to each unique weld, and available for post process evaluation. Installation of the Temate 2000 system in a major flat rolled steel mill has contributed to near elimination of weld breakage and increased productivity at this facility.

  1. Determination through the distortions analysis of the best welding sequence in longitudinal welds VATS electron beam welding FE simulation

    Energy Technology Data Exchange (ETDEWEB)

    Guirao, J., E-mail: julio@natec-ingenieros.co [Numerical Technologies, S.L., Marques de San Esteban No. 52, 33206 Gijon (Spain); Rodriguez, E. [Department of Mechanical Engineering, University of Oviedo, Campus de Viesques, 33203 Gijon (Spain); Bayon, A. [Vacuum Vessel Group, Fusion for Energy, Josep Pla 2, 08019 Barcelona (Spain); Bouyer, F. [DCNS, Indret 44620 LA MONTAGNE (France); Pistono, J. [Department of Thermal Machines and Motors, University of Oviedo, Campus de Viesques, 33203 Gijon (Spain); Jones, L. [Vacuum Vessel Group, Fusion for Energy, Josep Pla 2, 08019 Barcelona (Spain)

    2010-08-15

    This paper presents a detailed finite element simulation of the longitudinal rib welds of Vessel Advanced Technology Segment (VATS) by e-beam welding. Nine different simulation sequences were carried out to explain the different mechanisms that drive the distortions process during welding and to lead to an optimum sequence which minimizes the final distortions. The simulations were used to guide the manufacture of the final sequence of the VATS. Distortion measurements taken after welding compared very well with the simulated results.

  2. TECHNOLOGICAL ISSUES IN MECHANISED FEED WIG/TIG WELDING SURFACING OF WELDING

    Directory of Open Access Journals (Sweden)

    BURCA Mircea

    2016-09-01

    manual welding tests in the light of using the process for welding surfacing being known that in such applications mechanised operations are recommended whenever possible given the latter strengths i.e. increased productivity and quality deposits. The research also aims at achieving a comparative a study between wire mechanised feed based WIG manual welding and the manual rod entry based manual welding in terms of geometry deposits, deposits aesthetics, operating technique, productivity, etc . In this regard deposits were made by means of two welding procedures, and subsequently welding surfacing was made with the optimum values of the welding parameters in this case.

  3. Effects of welding technology on welding stress based on the finite element method

    Science.gov (United States)

    Fu, Jianke; Jin, Jun

    2017-01-01

    Finite element method is used to simulate the welding process under four different conditions of welding flat butt joints. Welding seams are simulated with birth and death elements. The size and distribution of welding residual stress is obtained in the four kinds of welding conditions by Q345 manganese steel plate butt joint of the work piece. The results shown that when using two-layers welding,the longitudinal and transverse residual stress were reduced;When welding from Middle to both sides,the residual stress distribution will change,and the residual stress in the middle of the work piece was reduced.

  4. Modeling of welded bead profile for rapid prototyping by robotic MAG welding

    Institute of Scientific and Technical Information of China (English)

    CAO Yong; ZHU Sheng; WANG Tao; WANG Wanglong

    2009-01-01

    As a deposition technology, robotic metal active gas(MAG) welding has shown new promise for rapid prototyping (RP) of metallic parts. During the process of metal forming using robotic MAG welding, sectional profile of single-pass welded bead is critical to formed accuracy and quality of metal pans. In this paper, the experiments of single-pass welded bead for rapid prototyping using robotic MAG welding were carried out. The effect of some edge detectors on the cross-sectional edge of welded bead was discussed and curve fitting was applied using leat square fitting. Consequently, the mathematical model of welded bead profile was developed. The experimental results show that good shape could be obtained under suitable welding parameters. Canny operawr is suitable to edge detection of welded bead profile, and the mathematical model of welded bead profile developed is approximately parabola.

  5. Predicting effects of diffusion welding parameters on welded joint properties by artificial neural network

    Institute of Scientific and Technical Information of China (English)

    刘黎明; 祝美丽; 牛济泰; 张忠典

    2001-01-01

    The static model for metal matrix composites in diffusion welding was established by means of artificial neural network method. The model presents the relationship between weld joint properties and welding parameters such as welding temperature, welding pressure and welding time. Through simulating the diffusion welding process of SiCw/6061Al composite, the effects of welding parameters on the strength of welded joint was studied and optimal technical parameters was obtained. It is proved that this method has good fault-tolerant ability and versatility and can overcome the shortage of the general experiment. The established static model is in good agreement with the actual welding process, so it becomes a new path for studying the weldability of new material.

  6. Effect of Laser Welding Parameters on Formation of NiTi Shape Memory Alloy Welds

    Directory of Open Access Journals (Sweden)

    Wei Wang

    2014-01-01

    Full Text Available In this work experimental trials of welding of NiTi flat plates with 2.0 mm thickness were conducted using a 4.5 kW continuous wave (CW Nd:YAG laser. The influences of laser output power, welding speed, defocus amount and side-blow shielding gas flow rate on the morphology, welding depth and width, and quality of the welded seam were investigated. Meanwhile, the effects of heat input on the mechanical and functional properties of welded joints were studied. The results show that laser welding can take better formation in NiTi alloys. The matching curves with laser power and welding speed affecting different formation of welds were experimentally acquired, which can provide references for laser welding and engineering application of NiTi alloy. The heat input has obvious effects on the ultimate tensile strength (UTS and shape memory behavior of the welded joints.

  7. Effect of weld reinforcement on axial plastic buckling of welded steel cylindrical shells

    Institute of Scientific and Technical Information of China (English)

    Chu-lin YU; Zhi-ping CHEN; Ji WANG; Shun-juan YAN; Li-cai YANG

    2012-01-01

    The effect of weld reinforcement on axial plastic buckling of welded steel cylindrical shells is investigated through experimental and numerical buckling analysis using six welded steel cylindrical shell specimens.The relationship between the amplitude of weld reinforcement and the axial plastic buckling critical load is explored.The effect of the material yield strength and the number of circumferential welds on the axial plastic buckling is studied.Results show that circumferential weld reinforcement represents a severe imperfect form of axially compressed welded steel cylindrical shells and the axial plastic buckling critical load decreases with the increment of the mean amplitude of circumferential weld reinforcement.The material yield strength and the number of circumferential welds are found to have no significant effect on buckling waveforms; however,the axial plastic buckling critical load can be decreased to some extent with the increase of the number of circumferential welds.

  8. Effect of Multi-repair Welding on Fatigue Performance of Aluminum Alloy Profile Welded Joint

    Science.gov (United States)

    Diao, You-De; Shi, Chun-Yuan; Tian, Hong-Lei

    2016-05-01

    Aluminum alloy profile has been widely used in the manufacture of the rail vehicles. But it's necessary for the repair welding of the welded joints to be conducted because some defects exist in the weld such as porosity, inclusions and incomplete penetrations in the welding processes. In this paper, the influence of the multi-repair welding of 6005A aluminum alloy profile butt welded joints on the fatigue performance are investigated based on the results of fatigue tests. The parameters of curves and the fatigue strength of the welded joints are calculated, and Goodman fatigue limit diagram is also obtained. The results show that fatigue strength of aluminum alloy profile butt welded joints, in condition of 107 cycle life, meet the standard requirement for the as-welded, repair welded state one time or two times respectively.

  9. Characteristics of Welding Crack Defects and Failure Mode in Resistance Spot Welding of DP780 Steel

    Institute of Scientific and Technical Information of China (English)

    Xiao-pei WANG; Yong-qiang ZHANG; Jian-bin JU; Jian-qiang ZHANG; Jian-wei YANG

    2016-01-01

    The mechanical properties of welded joints in resistance spot welding of DP780 steel were tested,and three dif-ferent types of welding cracks in welded joints were investigated by optical microscopy,scanning electron microscopy and electron back-scattered diffraction.Finally,the failure mode of the welded joints in shear tensile test was dis-cussed.It is found the shear tensile strength of welded joints can be greatly improved by adding preheating current or tempering current.The surface crack in welded joint is intergranular fracture,while the inner crack in welded joint is transgranular fracture,and the surface crack on the edge of the electrode imprint can be improved by adding prehea-ting current or tempering current.The traditional failure mode criterion advised by American Welding Society is no longer suitable for DP780 spot welds and the critical nugget size suggested by Pouranvari is overestimated.

  10. Effects of welding parameters on the mechanical properties of inert gas welded 6063 Aluminium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ertan, Taner [MAKO Corporation (Turkey); Uguz, Agah [Uludag Univ. (Turkey). Mechnical Engineering Dept.; Ertan, Rukiye

    2012-07-01

    The influence of welding parameters, namely welding current and gas flow rate, on the mechanical properties of Gas Tungsten Arc Welding (GTAW) and Shielded Metal Arc Welding (SMAW) welded 6063 Aluminum alloy (AA 6063) has been investigated. In order to study the effect of the welding current and gas flow rate, microstructural examination, hardness measurements and room temperature tensile tests have been carried out. The experimental results show that the mechanical properties of GTAW welded joints have better mechanical properties than those of SMAW welded joints. Increasing the welding current appeared to have a beneficial effect on the mechanical properties. However, either increasing or decreasing the gas flow rate resulted in a decrease of hardness and tensile strength. It was also found that, the highest strength was obtained in GTAW welded samples at 220 A and 15 l/min gas flow rate.

  11. Experimental and simulated strength of spot welds

    DEFF Research Database (Denmark)

    Nielsen, Chris Valentin; Bennedbæk, Rune A.K.; Larsen, Morten B.

    2014-01-01

    Weld strength testing of single spots in DP600 steel is presented for the three typical testing procedures, i.e. tensile-shear, cross-tension and peel testing. Spot welds are performed at two sets of welding parameters and strength testing under these conditions is presented by load-elongation cu......Weld strength testing of single spots in DP600 steel is presented for the three typical testing procedures, i.e. tensile-shear, cross-tension and peel testing. Spot welds are performed at two sets of welding parameters and strength testing under these conditions is presented by load......-elongation curves revealing the maximum load and the elongation at break. Welding and strength testing is simulated by SORPAS® 3D, which allows the two processes to be prepared in a combined simulation, such that the simulated welding properties are naturally applied to the simulation of strength testing. Besides...

  12. Polyimide weld bonding for titanium alloy joints

    Science.gov (United States)

    Vaughan, R. W.; Kurland, R. M.

    1974-01-01

    Two weld bonding processes were developed for joining titanium alloy; one process utilizes a weld-through technique and the other a capillary-flow technique. The adhesive used for the weld-through process is similar to the P4/A5F system. A new polyimide laminating resin, BFBI/BMPM, was used in the capillary-flow process. Static property information was generated for weld-bonded joints over the temperature range of 219 K (-65 F) to 561 K (+550 F) and fatigue strength information was generated at room temperature. Significant improvement in fatigue strength was demonstrated for weld-bonded joints over spot-welded joints. A demonstration was made of the applicability of the weld-through weld-bonding process for fabricating stringer stiffened skin panels.

  13. High capacity MnOx:ZrO2 sorbent for elementary mercury capture: preparation, characterization and comparison to other sorbents

    Science.gov (United States)

    Lakatos, J.; Snape, C. E.

    2017-02-01

    Manganese oxide-zirconia type (MnOx:ZrO2) sorbents were prepared using the sol-gel technique by co precipitation ZrO(NO3)2.xH2O and Mn(NO3)2 xH2O. The heat treatment below 500°C resulted a high surface area solid structure which consists of amorphous Mn2O3 (Bixbyite) and amorphous ZrO2 phases. This material was found a high capacity oxidative sorbent for mercury removal from gas streams.

  14. piggyBac as a high-capacity transgenesis and gene-therapy vector in human cells and mice

    Directory of Open Access Journals (Sweden)

    Rongbo Li

    2013-05-01

    The stable genomic integration and expression of a large transgene is a major hurdle in gene therapy. We show that the modified piggyBac (PB transposon system can be used to introduce a 207 kb genomic DNA fragment containing the RORγ/γt locus into human cells and mice. PB-mediated transgenesis results in a single copy of a stably inherited and expressed transgene. These results indicate that PB could serve as an effective high-capacity vector for functional analysis of the mammalian genome and for gene therapy in human cells.

  15. piggyBac as a high-capacity transgenesis and gene-therapy vector in human cells and mice

    OpenAIRE

    Rongbo Li; Yuan Zhuang; Min Han; Tian Xu; Xiaohui Wu

    2013-01-01

    SUMMARY The stable genomic integration and expression of a large transgene is a major hurdle in gene therapy. We show that the modified piggyBac (PB) transposon system can be used to introduce a 207 kb genomic DNA fragment containing the RORγ/γt locus into human cells and mice. PB-mediated transgenesis results in a single copy of a stably inherited and expressed transgene. These results indicate that PB could serve as an effective high-capacity vector for functional analysis of the mammalian ...

  16. Development of a new biofertilizer with a high capacity for N2 fixation, phosphate and potassium solubilization and auxin production.

    Science.gov (United States)

    Leaungvutiviroj, Chaveevan; Ruangphisarn, Pimtida; Hansanimitkul, Pikul; Shinkawa, Hidenori; Sasaki, Ken

    2010-01-01

    Biofertilizers that possess a high capacity for N(2) fixation (Azotobacter tropicalis), and consist of phosphate solubilizing bacteria (Burkhoderia unamae), and potassium solubilizing bacteria (Bacillus subtilis) and produce auxin (KJB9/2 strain), have a high potential for growth and yield enhancement of corn and vegetables (Chinese kale). For vegetables, the addition of biofertilizer alone enhanced growth 4 times. Moreover, an enhancement of growth by 7 times was observed due to the addition of rock phosphate and K-feldspar, natural mineral fertilizers, in combination with the biofertilizer.

  17. Experimental determination of the weld penetration evolution in keyhole plasma arc welding

    Institute of Scientific and Technical Information of China (English)

    Hu Qingxian; Wu Chuansong; Zhang Yuming

    2007-01-01

    Keyhole plasma arc welding experiments are conducted to measure the weld geometry and penetration at different moments during the initial phase from igniting arc to quasi-steady state. Indirect information on keyhole formation and evolution in plasma arc welding can be extracted based on the weld macrophotograph at cross section. It has laid foundation to verify the mathematical models of keyhole plasma arc welding.

  18. Welding polarity effects on weld spatters and bead geometry of hyperbaric dry GMAW

    Science.gov (United States)

    Xue, Long; Wu, Jinming; Huang, Junfen; Huang, Jiqiang; Zou, Yong; Liu, Jian

    2016-03-01

    Welding polarity has influence on welding stability to some extent, but the specific relationship between welding polarity and weld quality has not been found, especially under the hyperbaric environment. Based on a hyperbaric dry welding experiment system, gas metal arc welding(GMAW) experiments with direct current electrode positive(DCEP) and direct current electrode negative(DCEN) operations are carried out under the ambient pressures of 0.1 MPa, 0.4 MPa, 0.7 MPa and 1.0 MPa to find the influence rule of different welding polarities on welding spatters and weld bead geometry. The effects of welding polarities on the weld bead geometry such as the reinforcement, the weld width and the penetration are discussed. The experimental results show that the welding spatters gradually grow in quantity and size for GMAW with DCEP, while GMAW with DCEN can produce fewer spatters comparatively with the increase of the ambient pressure. Compared with DCEP, the welding current and arc voltage waveforms for DCEN is more stable and the distribution of welding current probability density for DCEN is more concentrated under the hyperbaric environment. When the ambient pressure is increased from 0.1 MPa to 1.0 MPa, the effects of welding polarities on the reinforcement, the weld width and the penetration are as follows: an increase of 0.8 mm for the weld reinforcement is produced by GMAW with DCEN and 1.3 mm by GMAW with DCEP, a decrease of 7.2 mm for the weld width is produced by DCEN and 6.1 mm by DCEP; and an increase of 3.9 mm for the penetration is produced by DCEN and 1.9 mm by DCEP. The proposed research indicates that the desirable stability in the welding procedure can be achieved by GMAW with DCEN operation under the hyperbaric environment.

  19. Welding Polarity Effects on Weld Spatters and Bead Geometry of Hyperbaric Dry GMAW

    Institute of Scientific and Technical Information of China (English)

    XUE Long; WU Jinming; HUANG Junfen; HUANG Jiqiang; ZOU Yong; LIU Jian

    2016-01-01

    Welding polarity has influence on welding stability to some extent, but the specific relationship between welding polarity and weld quality has not been found, especially under the hyperbaric environment. Based on a hyperbaric dry welding experiment system, gas metal arc welding(GMAW) experiments with direct current electrode positive(DCEP) and direct current electrode negative(DCEN) operations are carried out under the ambient pressures of 0.1 MPa, 0.4 MPa, 0.7 MPa and 1.0 MPa to find the influence rule of different welding polarities on welding spatters and weld bead geometry. The effects of welding polarities on the weld bead geometry such as the reinforcement, the weld width and the penetration are discussed. The experimental results show that the welding spatters gradually grow in quantity and size for GMAW with DCEP, while GMAW with DCEN can produce fewer spatters comparatively with the increase of the ambient pressure. Compared with DCEP, the welding current and arc voltage waveforms for DCEN is more stable and the distribution of welding current probability density for DCEN is more concentrated under the hyperbaric environment. When the ambient pressure is increased from 0.1 MPa to 1.0 MPa, the effects of welding polarities on the reinforcement, the weld width and the penetration are as follows: an increase of 0.8 mm for the weld reinforcement is produced by GMAW with DCEN and 1.3 mm by GMAW with DCEP, a decrease of 7.2 mm for the weld width is produced by DCEN and 6.1 mm by DCEP; and an increase of 3.9 mm for the penetration is produced by DCEN and 1.9 mm by DCEP. The proposed research indicates that the desirable stability in the welding procedure can be achieved by GMAW with DCEN operation under the hyperbaric environment.

  20. Closed circuit television welding alignment system

    Energy Technology Data Exchange (ETDEWEB)

    Darner, G.S.

    1976-09-01

    Closed circuit television (CCTV) weld targeting systems were developed to provide accurate and repeatable positioning of the electrode of an electronic arc welder with respect to the parts being joined. A sliding mirror electrode holder was developed for use with closed circuit television equipment on existing weld fixturing. A complete motorized CCTV weld alignment system was developed to provide weld targeting for even the most critical positioning requirements.

  1. Stereoscopic Video Weld-Seam Tracker

    Science.gov (United States)

    Kennedy, Larry Z.

    1991-01-01

    Stereoscopic video camera and laser illuminator operates in conjunction with image-data-processing computer to locate weld seam and to map surface features in vicinity of seam. Intended to track seams to guide placement of welding torch in automatic welding system and to yield information on qualities of welds. More sensitive than prior optical seam trackers and suitable for use in production environment. Tracks nearly invisible gap between butted machined edges of two plates.

  2. Welding distortion of aluminium structural members

    Energy Technology Data Exchange (ETDEWEB)

    Goglio, L. [Politecnico di Torino (Italy). Dept. of Mech.; Gugliotta, A. [Politecnico di Torino (Italy). Dept. of Mech.; Pasquino, D. [Politecnico di Torino (Italy). Dept. of Mech.

    1996-12-31

    The paper deals with the angular distortion induced in aluminium tubular beams during welding to prepare T junctions. The research, based on experimental measurements, makes use of statistical methods to identify the parameters (beam section, weld length, welding direction, etc.) that influence the angular change. The results are discussed also considering a model known from the literature. It is found that the distortion is generally low and can be minimized by a proper welding process. (orig.)

  3. Laser welding of advanced high strength steels

    OpenAIRE

    Ahmed, Essam Ahmed Ali

    2011-01-01

    This research work focuses on characterization of CO2 laser beam welding (LBW) of dual phase (DP) and transformation induced plasticity (TRIP) steel sheets based on experimental, numerical simulation and statistical modeling approaches. The experimental work aimed to investigate the welding induced-microstructures, hardness, tensile properties and formability limit of laser welding butt joints of DP/DP, TRIP/TRIP and DP/TRIP steel sheets under different welding speeds. The effects of shieldin...

  4. Welding technology for rails. Rail no setsugo gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    Okumura, M.; Karimine, K. (Nippon Steel Corp., Tokyo (Japan)); Uchino, K.; Sugino, K. (Nippon Steel Corp., Kitakyushu, Fukuoka (Japan). Technical Research Inst. of Yawata Works); Ueyama, K. (JR Railway Technical Research Inst., Tokyo (Japan))

    1993-08-01

    The rail joining technology is indispensable for making long welded rails. Flush butt welding, gas welding, enclosed arc welding, and thermit welding are used properly as the welding methods. A method for improving the joint reliability by controlling the residual stress distribution of welded joint is investigated to prepare high carbon component weld metal similar to the rail. Problems with each of the welding methods and the newly developed technology to solve the problems are outlined. Composition of the coating is improved also, and a high C system welding rod is developed which has satisfactory weldability. High performance and high efficient new enclosed arc welding technology not available by now is developed which utilizes high carbon welding metal as a new EA welding work technology, and put to practical use. As a result of this study, useful guides are obtained for the establishment of satisfactory thermit welding technology. 17 refs., 16 figs., 1 tab.

  5. Laser weld process monitoring and control using chromatic filtering of thermal radiation from a weld pool

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Cheol Jung; Kim, Min Suk; Baik, Sung Hoon; Chung, Chin Man

    2000-06-01

    The application of high power Nd: YAG lasers for precision welding in industry has been growing quite fast these days in diverse areas such as the automobile, the electronics and the aerospace industries. These diverse applications also require the new developments for the precise control and the reliable process monitoring. Due to the hostile environment in laser welding, a remote monitoring is required. The present development relates in general to weld process monitoring techniques, and more particularly to improved methods and apparatus for real-time monitoring of thermal radiation of a weld pool to monitor a size variation and a focus shift of the weld pool for weld process control, utilizing the chromatic aberration of focusing lens or lenses. The monitoring technique of the size variation and the focus shift of a weld pool is developed by using the chromatic filtering of the thermal radiation from a weld pool. The monitoring of weld pool size variation can also be used to monitor the weld depth in a laser welding. Furthermore, the monitoring of the size variation of a weld pool is independent of the focus shift of a weld pool and the monitoring of the focus shift of a weld pool is independent of the size variation of a weld pool.

  6. Welding of aluminum with linear ribbon explosives.

    Science.gov (United States)

    Bement, L. J.

    1971-01-01

    A small-scale simplified, parallel plate process of welding aluminum with very small quantities of lead-sheathed linear ribbon RDX explosive is described. The results of the welding of five different alloys, obtained by using this technique, show that the weld strengths are up to 90% of the parent metal tensile strength.

  7. 49 CFR 195.224 - Welding: Weather.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Welding: Weather. 195.224 Section 195.224 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... PIPELINE Construction § 195.224 Welding: Weather. Welding must be protected from weather conditions...

  8. 49 CFR 179.400-11 - Welding.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Welding. 179.400-11 Section 179.400-11...-11 Welding. (a) Except for closure of openings and a maximum of two circumferential closing joints in... subchapter). (d) Each welding procedure, welder, and fabricator must be approved. [Amdt. 179-32, 48 FR...

  9. 49 CFR 179.220-10 - Welding.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Welding. 179.220-10 Section 179.220-10... Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.220-10 Welding. (a) All joints... of this subchapter). Welding procedures, welders, and fabricators shall be approved. (b)...

  10. 49 CFR 179.200-10 - Welding.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Welding. 179.200-10 Section 179.200-10... Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.200-10 Welding. (a) All joints... W (IBR, see § 171.7 of this subchapter). Welding procedures, welders and fabricators shall...

  11. 46 CFR 154.660 - Pipe welding.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Pipe welding. 154.660 Section 154.660 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR... § 154.660 Pipe welding. (a) Pipe welding must meet Part 57 of this chapter. (b) Longitudinal butt...

  12. 49 CFR 179.100-9 - Welding.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Welding. 179.100-9 Section 179.100-9... Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.100-9 Welding. (a) All..., appendix W (IBR, see § 171.7 of this subchapter). Welding procedures, welders and fabricators shall...

  13. Experimental analysis of cut welding in aluminium

    DEFF Research Database (Denmark)

    Dorph, Pernille; De Chiffre, Leonardo; Bay, Niels

    1993-01-01

    Cut welding is a newly developed cold pressure welding process. In the present work, an experimental investigation was carried out analyzing the mechanisms involved in cut welding of a block to a strip. Experiments were carried out in technically pure aluminium. The investigation has involved...

  14. Friction welding thermal and metallurgical characteristics

    CERN Document Server

    Yilbas, Bekir Sami

    2014-01-01

    This book provides insight into the thermal analysis of friction welding incorporating welding parameters such as external, duration, breaking load, and material properties. The morphological and metallurgical changes associated with the resulting weld sites are analysed using characterization methods such as electron scanning microscope, energy dispersive spectroscopy, X-ray Diffraction, and Nuclear reaction analysis.

  15. Resistance welding equipment manufacturing capability for exports

    Energy Technology Data Exchange (ETDEWEB)

    Sastry, V.S.; Raju, Y.S.; Somani, A.K.; Setty, D.S.; Rameswara Raw, A.; Hermantha Rao, G.V.S.; Jayaraj, R.N. [Nuclear Fuel Complex, Dept. of Atomic Energy, Hyderbad (India)

    2010-07-01

    Indian Pressurised Heavy Water Reactor (PHWR) fuel bundle is fully welded and is unique in its design. Appendage welding, end closure welding, and end plate welding is carried out using resistance welding technique. Out of many joining processes available, resistance-welding process is reliable, environment friendly and best suitable for mass production applications. Nuclear Fuel Complex (NFC), an industrial unit is established in Hyderabad, under the aegis of the Dept of Atomic Energy to manufacture fuel for Pressurised Heavy Water Reactors. From inception, NFC has given importance for self-reliance and indigenization with respect to manufacturing process and equipment. Sintering furnaces, centreless grinders, appendage-welding machines, end-closure welding equipment and end-plate welding equipments, which were initially imported, are either indigenized or designed and manufactured in house. NFC has designed, manufactured a new appendage-welding machine for manufacturing 37 element fuel bundles. Recently NFC has bagged an order from IAEA through international bidding for design, manufacture, supply, erection and commissioning of end-closure welding equipment. The paper gives in detail the salient features of these welding equipment. (author)

  16. Automatic Guidance System for Welding Torches

    Science.gov (United States)

    Smith, H.; Wall, W.; Burns, M. R., Jr.

    1984-01-01

    Digital system automatically guides welding torch to produce squarebutt, V-groove and lap-joint weldments within tracking accuracy of +0.2 millimeter. Television camera observes and traverses weld joint, carrying welding torch behind. Image of joint digitized, and resulting data used to derive control signals that enable torch to track joint.

  17. Electron Beam Welding to Join Gamma Titanium Aluminide Articles

    Science.gov (United States)

    Kelly, Thomas Joseph (Inventor)

    2008-01-01

    A method is provided for welding two gamma titanium aluminide articles together. The method includes preheating the two articles to a welding temperature of from about 1700 F to about 2100 F, thereafter electron beam welding the two articles together at the welding temperature and in a welding vacuum to form a welded structure, and thereafter annealing the welded structure at an annealing temperature of from about 1800 F to about 2200 F, to form a joined structure.

  18. Materials and welding engineering in advanced coal utilization plants

    Energy Technology Data Exchange (ETDEWEB)

    Schuhmacher, D.; Schulze-Frielinghaus, W.; Puetz, J.; Eichhorn, F.; Gaever, E. van

    1983-08-01

    The authors present the findings of studies on welding methods for high-temperature alloys used in advanced coal gasification plants. They discuss weld preparation, automatic TIG welding, MIG welding (also with pulsed arc) and plasma arc welding. The mechanical properties of welded joints before and after age hardening are investigated, and the results of fatigue and corrosion tests are presented. The welding methods are compared with a view to their suitability for high-temperature materials.

  19. When high-capacity readers slow down and low-capacity readers speed up: Working memory and locality effects

    Directory of Open Access Journals (Sweden)

    Bruno eNicenboim

    2016-03-01

    Full Text Available We examined the effects of argument-head distance in SVO and SOV languages (Spanish and German, while taking into account readers’ working memory capacity and controlling for expectation (Levy, 2008 and other factors. We predicted only locality effects, that is, a slow-down produced by increased dependency distance (Gibson, 2000; Lewis & Vasishth, 2005. Furthermore, we expected stronger locality effects for readers with low working memory capacity. Contrary to our predictions, low-capacity readers showed faster reading with increased distance, while high-capacity readers showed locality effects. We suggest that while the locality effects are compatible with memory-based explanations, the speedup of low-capacity readers can be explained by an increased probability of retrieval failure. We present a computational model based on ACT-R built under the previous assumptions, which is able to give a qualitative account for the present data and can be tested in future research. Our results suggest that in some cases, interpreting longer RTs as indexing increased processing difficulty and shorter RTs as facilitation may be too simplistic: The same increase in processing difficulty may lead to slowdowns in high-capacity readers and speedups in low-capacity ones. Ignoring individual level capacity differences when investigating locality effects may lead to misleading conclusions.

  20. Life cycle environmental impact of high-capacity lithium ion battery with silicon nanowires anode for electric vehicles.

    Science.gov (United States)

    Li, Bingbing; Gao, Xianfeng; Li, Jianyang; Yuan, Chris

    2014-01-01

    Although silicon nanowires (SiNW) have been widely studied as an ideal material for developing high-capacity lithium ion batteries (LIBs) for electric vehicles (EVs), little is known about the environmental impacts of such a new EV battery pack during its whole life cycle. This paper reports a life cycle assessment (LCA) of a high-capacity LIB pack using SiNW prepared via metal-assisted chemical etching as anode material. The LCA study is conducted based on the average U.S. driving and electricity supply conditions. Nanowastes and nanoparticle emissions from the SiNW synthesis are also characterized and reported. The LCA results show that over 50% of most characterized impacts are generated from the battery operations, while the battery anode with SiNW material contributes to around 15% of global warming potential and 10% of human toxicity potential. Overall the life cycle impacts of this new battery pack are moderately higher than those of conventional LIBs but could be actually comparable when considering the uncertainties and scale-up potential of the technology. These results are encouraging because they not only provide a solid base for sustainable development of next generation LIBs but also confirm that appropriate nanomanufacturing technologies could be used in sustainable product development.

  1. Microstructure modeling in weld metal

    Energy Technology Data Exchange (ETDEWEB)

    David, S.A.; Babu, S.S.

    1995-12-31

    Since microstructure development in the weld metal region is controlled by various physical processes, there is a need for integrated predictive models based on fundamental principles to describe and predict the effect of these physical processes. These integrated models should be based on various tools available for modeling microstructure development in a wide variety of alloy systems and welding processes. In this paper, the principles, methodology, and future directions of modeling thermochemical reactions in liquid, solidification, and solid state transformations are discussed with some examples for low-alloy steel, stainless steel, and Ni-base superalloy. Thermochemical deoxidation reactions in liquid low-alloy steel lead to oxide inclusion formation. This inclusion formation has been modeled by combining principles of ladle metallurgy and overall transformation kinetics. The model`s comparison with the experimental data and the ongoing work on coupling this inclusion model with the numerical models of heat transfer and fluid flow are discussed. Also, recent advances in theoretical and physical modeling of the solidification process are reviewed with regard to predicting the solidification modes, grain structure development, segregation effects, and nonequilibrium solidification in welds. The effects of solid state phase transformations on microstructure development and various methods of modeling these transformations are reviewed. Successful models, based on diffusion-controlled growth and plate growth theories, on microstructure development in low-alloy steel and stainless steel weld metals are outlined. This paper also addresses the importance of advanced analytical techniques to understand the solid state transformation mechanisms in welds.

  2. Contamination and solid state welds.

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Bernice E.

    2007-05-01

    Since sensitivity to contamination is one of the verities of solid state joining, there is a need for assessing contamination of the part(s) to be joined, preferably nondestructively while it can be remedied. As the surfaces that are joined in pinch welds are inaccessible and thus provide a greater challenge, most of the discussion is of the search for the origin and effect of contamination on pinch welding and ways to detect and mitigate it. An example of contamination and the investigation and remediation of such a system is presented. Suggestions are made for techniques for nondestructive evaluation of contamination of surfaces for other solid state welds as well as for pinch welds. Surfaces that have good visual access are amenable to inspection by diffuse reflection infrared Fourier transform (DRIFT) spectroscopy. Although other techniques are useful for specific classes of contaminants (such as hydrocarbons), DRIFT can be used most classes of contaminants. Surfaces such as the interior of open tubes or stems that are to be pinch welded can be inspected using infrared reflection spectroscopy. It must be demonstrated whether or not this tool can detect graphite based contamination, which has been seen in stems. For tubes with one closed end, the technique that should be investigated is emission infrared spectroscopy.

  3. Constraints on the Moment of Inertia of a Proto Neutron Star from the Hyperon Coupling Constants

    Indian Academy of Sciences (India)

    Xian-Feng Zhao; Huan-Yu Jia

    2012-09-01

    The influence of the hyperon coupling constants on the moment of inertia of a proto neutron star has been investigated within the framework of relativistic mean field theory for the baryon octet {, , , -, 0, +, Ξ-, Ξ0} system. It is found that for a proto neutron star, the mass, the moment of inertia and their own maximum values as a function of radius or / are all more sensitive to the hyperon coupling constants. For all the different hyperon coupling constants mentioned, the case of no hyperons corresponds to the largest moment of inertia.

  4. Atomistic spin dynamic method with both damping and moment of inertia effects included from first principles.

    Science.gov (United States)

    Bhattacharjee, Satadeep; Nordström, Lars; Fransson, Jonas

    2012-02-03

    We consider spin dynamics for implementation in an atomistic framework and we address the feasibility of capturing processes in the femtosecond regime by inclusion of moment of inertia. In the spirit of an s-d-like interaction between the magnetization and electron spin, we derive a generalized equation of motion for the magnetization dynamics in the semiclassical limit, which is nonlocal in both space and time. Using this result we retain a generalized Landau-Lifshitz-Gilbert equation, also including the moment of inertia, and demonstrate how the exchange interaction, damping, and moment of inertia, all can be calculated from first principles.

  5. The calculation of the mass moment of inertia of a fluid in a rotating rectangular tank

    Science.gov (United States)

    1977-01-01

    This analysis calculated the mass moment of inertia of a nonviscous fluid in a slowly rotating rectangular tank. Given the dimensions of the tank in the x, y, and z coordinates, the axis of rotation, the percentage of the tank occupied by the fluid, and angle of rotation, an algorithm was written that could calculate the mass moment of inertia of the fluid. While not included in this paper, the change in the mass moment of inertia of the fluid could then be used to calculate the force exerted by the fluid on the container wall.

  6. Surface corrections to the shell-structure of the moment of inertia

    CERN Document Server

    Gorpinchenko, D V; Bartel, J; Blocki, J P

    2015-01-01

    The moment of inertia for nuclear collective rotations is derived within a semiclassical approach based on the Inglis cranking and the Strutinsky shell-correction methods, improved by surface corrections within the non-perturbative periodic-orbit theory. For adiabatic (statistical-equilibrium) rotations it was approximated by the generalized rigid-body moment of inertia accounting for the shell corrections of the particle density. An improved phase-space trace formula allows to express the shell components of the moment of inertia more accurately in terms of the free-energy shell correction with their ratio evaluated within the extended Thomas-Fermi effective-surface approximation.

  7. Moments of Inertia: Uninhabited Aerial Vehicle (UAV) Dryden Remotely Operated Integrated Drone (DROID)

    Science.gov (United States)

    Haro, Helida C.

    2010-01-01

    The objective of this research effort is to determine the most appropriate, cost efficient, and effective method to utilize for finding moments of inertia for the Uninhabited Aerial Vehicle (UAV) Dryden Remotely Operated Integrated Drone (DROID). A moment is a measure of the body's tendency to turn about its center of gravity (CG) and inertia is the resistance of a body to changes in its momentum. Therefore, the moment of inertia (MOI) is a body's resistance to change in rotation about its CG. The inertial characteristics of an UAV have direct consequences on aerodynamics, propulsion, structures, and control. Therefore, it is imperative to determine the precise inertial characteristics of the DROID.

  8. Moments of Inertia - Uninhabited Aerial Vehicle (UAV) Dryden Remotely Operated Integrated Drone (DROID)

    Science.gov (United States)

    Haro, Helida C.

    2010-01-01

    The objective of this research effort is to determine the most appropriate, cost efficient, and effective method to utilize for finding moments of inertia for the Uninhabited Aerial Vehicle (UAV) Dryden Remotely Operated Integrated Drone (DROID). A moment is a measure of the body's tendency to turn about its center of gravity (CG) and inertia is the resistance of a body to changes in its momentum. Therefore, the moment of inertia (MOI) is a body's resistance to change in rotation about its CG. The inertial characteristics of an UAV have direct consequences on aerodynamics, propulsion, structures, and control. Therefore, it is imperative to determine the precise inertial characteristics of the DROID.

  9. Study of Mechanical Properties and Characterization of Pipe Steel welded by Hybrid (Friction Stir Weld + Root Arc Weld) Approach

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Yong Chae [ORNL; Sanderson, Samuel [MegaStir Technologies LLC; Mahoney, Murray [Consultant; Wasson, Andrew J [ExxonMobil, Upstream Research Company (URC); Fairchild, Doug P [ExxonMobil, Upstream Research Company (URC); Wang, Yanli [ORNL; Feng, Zhili [ORNL

    2015-01-01

    Friction stir welding (FSW) has recently attracted attention as an alternative construction process for gas/oil transportation applications due to advantages compared to fusion welding techniques. A significant advantage is the ability of FSW to weld the entire or nearly the entire wall thickness in a single pass, while fusion welding requires multiple passes. However, when FSW is applied to a pipe or tube geometry, an internal back support anvil is required to resist the plunging forces exerted during FSW. Unfortunately, it may not be convenient or economical to use internal backing support due to limited access for some applications. To overcome this issue, ExxonMobil recently developed a new concept, combining root arc welding and FSW. That is, a root arc weld is made prior to FSW that supports the normal loads associated with FSW. In the present work, mechanical properties of a FSW + root arc welded pipe steel are reported including microstructure and microhardness.

  10. A Stereo Vision Visualization Method in Welding

    Science.gov (United States)

    Zhao, Chuangxin; Richardson, Ian M.; Kleijn, Chris; Kenjeres, Sasa; Saldi, Zaki

    2008-09-01

    The oscillation of weld pool surface, vaporization and spatters make the measurement in welding difficult; two dimensional results can not reflect enough information in welding. However, there are few direct three dimensional methods to understand the fluid flow during welding. In this paper, we described a three dimensional reconstruction method to measure velocity in welding based on a single high speed camera. A stereo adapter was added in front of the high speed camera lens to obtain two images in the same frame from different view points at the same time; according to the machine vision theory, three dimensional parameters could be reconstructed based on these two images

  11. Explosive welding: Principles and potentials

    Energy Technology Data Exchange (ETDEWEB)

    Brasher, D.G.; Butler, D.J. [Northwest Technical Industries, Inc., Sequim, WA (United States)

    1995-03-01

    Explosive welding is a solid-state process in which controlled explosive detonations force two or more metals together at high pressures. The resultant composite system is joined with a high-quality metallurgical bond. Explosive welding (or explosive bonding) is a high-pressure process in which contaminant surface films are plastically jetted off the base metals as a result of the collision of two metals. The time duration involved in the explosive welding event is so short that the reaction zone (or heat affected zone) between the constituent metals is microscopic. During the process, the first few atomic layers of each metal become plasma because of the high velocity of the impact (200 to 500 m/s, 660 to 1,640 ft/s.) The angle of collision causes the plasma to jet in front of the collision point, effectively scrub-cleaning both surfaces, and leaving clean metal behind.

  12. High frequency welded (ERW) casing

    Energy Technology Data Exchange (ETDEWEB)

    Duisberg, J. (Hoesch Roehrenwerke A.G., Hamm (Germany, F.R.))

    1980-09-01

    Due to the up-to-date standard in welding and testing techniques, the significance of ERW-casing is growing rapidly. The basic items of ERW-pipe are explained in detail. The forming mechanism, the high frequency welding by induction and contact welding processes is explained in detail as well as destructive and non-destructive testing methods. Finishing the ends as threading, thread control (gauging), power tight connection, pressure test and final quality control are rounding up the picture of the production of ERW-casing. Last but not least the test results from the joint strength- and collapse tests which are of outstanding interest for casings, are compared with API requirements in order to demonstrate compliance with API requirements.

  13. Intraluminal tissue welding for anastomosis

    Science.gov (United States)

    Glinsky, Michael; London, Richard; Zimmerman, George; Jacques, Steven

    1998-10-27

    A method and device are provided for performing intraluminal tissue welding for anastomosis of a hollow organ. A retractable catheter assembly is delivered through the hollow organ and consists of a catheter connected to an optical fiber, an inflatable balloon, and a biocompatible patch mounted on the balloon. The disconnected ends of the hollow organ are brought together on the catheter assembly, and upon inflation of the balloon, the free ends are held together on the balloon to form a continuous channel while the patch is deployed against the inner wall of the hollow organ. The ends are joined or "welded" using laser radiation transmitted through the optical fiber to the patch. A thin layer of a light-absorbing dye on the patch can provide a target for welding. The patch may also contain a bonding agent to strengthen the bond. The laser radiation delivered has a pulse profile to minimize tissue damage.

  14. Chaotic Inertia Weight Particle Swarm Optimization for PCR Primer Design

    Directory of Open Access Journals (Sweden)

    Cheng-Huei Yang

    2013-06-01

    Full Text Available In order to provide feasible primer sets for performing a polymerase chain reaction (PCR experiment, many primer design methods have been proposed. However, the majority of these methods require a long time to obtain an optimal solution since large quantities of template DNA need to be analyzed, and the designed primer sets usually do not provide a specific PCR product size. In recent years, particle swarm optimization (PSO has been applied to solve many problems and yielded good results. In this paper, a logistic map is proposed to determine the value of inertia weight of PSO (CIWPSO to design feasible primers. Accuracies for the primer design of the Homo sapiens RNA binding motif protein 11 (RBM11, mRNA (NM_144770, and the Homo sapiens G protein-coupled receptor 78 (GPR78, mRNA (NM_080819 were calculated. Five hundred runs of PSO and the CIWPSO primer design method were performed on different PCR product lengths and the different methods of calculating the melting temperature. A comparison of the accuracy results for PSO and CIWPSO primer design showed that CIWPSO is superior to the PSO for primer design. The proposed method could effectively find optimal or near-optimal primer sets.

  15. Experimental status of thrusting by electromagnetic inertia manipulation

    Energy Technology Data Exchange (ETDEWEB)

    Brito, H.H. [Instituto Universitario, Cordoba (Argentina)

    2004-04-01

    It has been shown in previous works that given suitable charge and current distributions, the electromagnetic (EM) field can modify the inertial properties of the generating device if Minkowski's energy-momentum tensor holds for the description of field-matter interactions. The possibility then arises of obtaining mechanical impulses on the device, not undergoing any exchange of mass-energy with the surrounding medium, by EM inertia manipulation (EMIM). The aim of this paper is to present the accumulated experimental evidence about that means of achieving thrust. Three test series performed during the periods 1993-1997 and 1999-2000 on different experimental setups, are reviewed from the viewpoint of an identification of systematic spurious effects. A fourth series of tests recently conducted yields results that can hardly be explained without the EMIM mechanism. However, they are in contradiction with null results predicted by the currently admitted formulation of global EM forces. Further progress along this line of research will likely require improved test and measurement procedures, to get rid of residual spurious effects. Enhanced reliability of the reported results is also expected to arise from independent confirmation by other researchers. (author)

  16. Information transfer and behavioural inertia in starling flocks

    Science.gov (United States)

    Attanasi, Alessandro; Cavagna, Andrea; Del Castello, Lorenzo; Giardina, Irene; Grigera, Tomas S.; Jelić, Asja; Melillo, Stefania; Parisi, Leonardo; Pohl, Oliver; Shen, Edward; Viale, Massimiliano

    2014-09-01

    Collective decision-making in biological systems requires all individuals in the group to go through a behavioural change of state. During this transition fast and robust transfer of information is essential to prevent cohesion loss. The mechanism by which natural groups achieve such robustness, however, is not clear. Here we present an experimental study of starling flocks performing collective turns. We find that information about direction changes propagates across the flock with a linear dispersion law and negligible attenuation, hence minimizing group decoherence. These results contrast starkly with present models of collective motion, which predict diffusive transport of information. Building on spontaneous symmetry breaking and conservation-law arguments, we formulate a theory that correctly reproduces linear and undamped propagation. Essential to this framework is the inclusion of the birds' behavioural inertia. The theory not only explains the data, but also predicts that information transfer must be faster the stronger the group's orientational order, a prediction accurately verified by the data. Our results suggest that swift decision-making may be the adaptive drive for the strong behavioural polarization observed in many living groups.

  17. Frontal instability and the radiation of inertia gravity waves

    Science.gov (United States)

    Flór, J.-B.; Scolan, H.

    2009-04-01

    In this experimental study we consider the instability of a density front in a differentially rotating two-layer fluid. Within the rotating frame the upper layer is accelerated by the differential rotation of a lid at the surface. In contrast to former comparable experiments of this type, we consider miscible fluids in a relatively wide annular tank. Velocity and dye measurements (PIV and LIF) allow for the measurements of the velocity and density fields. In the parameter space set by rotational Froude number and dissipation (i.e. ratio of spin-down time to disk rotation time), different flow regimes are observed, ranging from axisymmetric to irregular baroclinic instable flows. The different regimes more or less adjoin those found for immiscible fluids by Williams et al. (J. Fluid Mech. 2005). In the present experiments, we find a new type of instability that is due to the resonant interaction between Kelvin and Rossby waves (first studied Sakai, J. Fluid Mech 1989) and compare our experimental results with the analytical results obtained on an annular domain by Gula, Zeitlin and Plougonven (2009). Further, observations in the unstable flow regimes suggest 'spontaneous emission' of inertia gravity waves. The origin of these waves is discussed in the light of Kelvin-Helmholtz instability Hölmböe instability, and geostrophic adjustment waves.

  18. Decoupling the Role of Inertia and Gravity on Particle Dispersion

    Science.gov (United States)

    Rogers, Chris; Squires, Kyle

    1996-01-01

    Turbulent gas flows laden with small, dense particles are encountered in a wide number of important applications in both industrial settings and aerodynamics applications. Particle interactions with the underlying turbulent flow are exceedingly complex and, consequently, difficult to accurately model. The difficulty arises primarily due to the fact that response of a particle to the local environment is dictated by turbulence properties in the reference frame moving with the particle (particle-Lagrangian). The particle-Lagrangian reference frame is in turn dependent upon the particle relaxation time (time constant) as well as gravitational drift. The combination of inertial and gravitational effects in this frame complicates our ability to accurately predict particle-laden flows since measurements in the particle-Lagrangian reference frame are difficult to obtain. Therefore, in this work we will examine separately the effects of inertia and gravitational drift on particle dispersion through a combination of physical and numerical experiments. In this study, particle-Lagrangian measurements will be obtained in physical experiments using stereo image velocimetry. Gravitational drift will be varied in the variable-g environments of the NASA DC-9 and in the zero-g environment at the drop tower at NASA-Lewis. Direct numerical simulations will be used to corroborate the measurements from the variable-g experiments. We expect that this work will generate new insight into the underlying physics of particle dispersion and will, in turn, lead to more accurate models of particle transport in turbulent flows.

  19. Relationship between sound signal and weld pool status in plasma arc welding

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The sound features of the weld pool status in plasma arc welding were systematically investigated after the sound signal was collected with a microphone. The results show that it is difficult to extract information about the weld pool status directly in time domain although the sound signal varies with the weld pool behaviors to some extent. The frequency spectra of the sound signal contain plenty of information about the weld pool behaviors. It is shown from the analysis of the sound generation mechanism that the sound signal of plasma arc welding is mainly caused by the weld pool oscillation, the power source fluctuation and so on. RS algorithm is designed to determine the weld pool status, and it is able to offer the feedback information for the closed-loop control of the penetration quality of plasma arc welding.

  20. Simulation of Weld Depth in A-TIG Welding with Unified Arc-electrode model

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Calculations have been made for weld depths occurring for TIG welding activated by a flux over the surface of the weld pool. In this case, the flux introduces an electrically insulating layer over the outer regions of the weld-pool surface. There is then an increase in the current density at the surface of the centre of the weld-pool with a consequent increase in the J×B forces, which drive a strong convective flow of the molten metal downwards, tending to make a deep weld. For a flux which produces an insulating layer for all but a central region of radius 2 mm, the calculated weld-depth is 7 mm, and an arc spot is predicted at the centre of the weld-pool surface. As yet we have not resolved the reason for significant differences that exist between our measurements of weld depth and the theoretical predictions.