A laboratory experiment was performed to investigate the three-dimensional turbulence and kinematic properties that develop due to a breaking solitary and an irregular shallow water bathymetry. A large basin equipped with a piston-type wavemaker was used to generate the wave, while the free surface elevations and fluid velocities were measured using wave gauges and three-dimensional acoustic-Doppler velocimeters (ADVs), respectively. From the free surface elevations, the evolution and runup of the wave was revealed; while from the ADVs, the velocity and turbulent energy was determined to identify specific turbulent events and coherent structures. It was found that shoaling was confined to areas with gentler sloping bathymetry near the basin side walls and the runup shoreward of the still water shoreline was not uniform. The runup was characterized by a jetting mechanism caused by the convergence of water mass near the basin centerline as the wave refracted during breaking. The jetting mechanism caused the greatest cross-shore velocities to be located near the basin centerline. The greatest turbulent events were well correlated to borefronts, resembling hydraulic jumps, where the greatest shear and fluid accelerations occurred. Because of an abrupt change in the bathymetry, a coherent structure developed which was found to have a three-dimensional flow field. It was proposed that variations in the internal flow with depth were due to the orientation of multiple vortex rings.

Perennial ryegrass (Lolium perenne L.) is commonly overseeded into hybrid bermudagrass [Cynodon dactylon (L.) Pers. X C. transvaalensis Burtt Davy] turfs during autumn in the southern United States. Overseeding can provide a green, actively-growing turf throughout the winter dormancy period. Improved persistence of perennial ryegrass cultivars has increased management inputs during the spring transition period. Lower input turf systems that provide acceptable winter overseeding quality are preferred, and research aimed at evaluating alternative overseeding species are warranted. Grooming reel attachments allowing for threedimensional clipping management (3DCM) have become increasingly used by turf managers for reducing grain and thatch, but scientific information on best management practices and canopy effects of 3DCM-grooming are lacking. A field study was conducted at the Texas A&M Turfgrass Field Laboratory in College Station, TX (30.6191 degrees N, 96.3576 degrees W), to investigate the effects of overseeding using annual (Lolium multiflorum Lam.) and perennial ryegrasses on 3DCM-groomed and non-groomed fairway turfs of 'Tifway' hybrid bermudagrass, zoysiagrass [Zoysia matrella (L.) Merr. 'Cavalier'], and seashore paspalum (Paspalum vaginatum Sw. 'Sea Isle 1'). The study was arranged as a randomized complete block split-split-plot with three replications. Species whole main plots were split into three grooming intervals, which were further split into four overseeding treatments. Data were collected assessing visual turf quality, visual turf cover, leaf area index, clipping yield, shoot density, and biomass partitioning. Results indicate annual ryegrass alone and an annual/perennial ryegrass overseeding mix provided acceptable turf quality, but did not improve turf recovery over perennial ryegrass alone in 'Tifway' or 'Sea Isle 1' turfs. In 'Cavalier' turfs, summer quality was affected by overseeding treatment as follows: control > annual > annual/perennial > perennial. The overseeding tolerance of the warm-season turfgrasses was as follows: 'Sea Isle 1' > 'Tifway' > 'Cavalier'. Differences in canopy architecture of warm-season turfgrasses were related to the overseeding tolerance of each species and used to explain plant competition during the spring transition period. Grooming by 3DCM improved late-season turf quality and reduced scalping in 'Tifway'. Overseeding establishment and canopy architecture were not affected by 3DCM.

The vascular endothelium continually senses and responds to both biochemical and mechanical stimuli to regulate vascular function in health and disease. The purpose of this dissertation was to understand the molecular mechanisms by which endothelial cells (ECs) respond to sphingosine 1-phosphate (S1P) and fluid wall shear stress (WSS) to initiate angiogenesis. To accomplish this, a novel cell culture system was developed to study the combined effects of S1P and WSS on inducing EC invasion into three-dimensional (3-D) collagen matrices. EC invasion required the presence of S1P, with the effects of S1P being enhanced by WSS to an extent comparable with S1P combined with pro-angiogenic growth factor stimulation. The extent of EC invasion depended on the magnitude of WSS in a biphasic manner, with the greatest induction occurring at 5.3 dyn/cm2 WSS. Several proteins have been implicated in EC invasion, including calpain, Akt, vimentin, p21-activated kinase (PAK), and membrane type 1-matrix metalloproteinase (MT1-MMP). Interestingly, activations of calpain and MT1-MMP and phosphorylations of Akt, PAK, and vimentin coincided with, and were required for, S1P- and WSS- induced EC invasion. Further, inhibitors of calpain, MT1-MMP, Akt and PAK all attenuated invasion induced by WSS and S1P. Calpain inhibition reduced Akt phosphorylation, vimentin cleavage, and MT1-MMP membrane translocation, suggesting that calpain regulates MT1-MMP via Akt phosphorylation and vimentin remodeling. Akt inhibition also completely blocked MT1-MMP membrane translocation and decreased phosphorylation of PAK and vimentin. In summary, these results suggest a new molecular pathway by which the combination of S1P and WSS stimulates EC invasion through calpain, Akt, PAK and vimentin to regulate activation and membrane translocation of MT1-MMP in 3-D collagen matrices.

This research is based on neo-functionalism to analysis the extent of cooperation in Taiwan and Mainland China in the sector of automobile industry, and how it will affect the government policy between Cross-Strait relations. Since Mainland China to open up its market, there are more and more Taiwanese businessmen to invest in Mainland China. The relation between Taiwan and Mainland China is more closely, especially after accession in WTO. According to the discourse of neo-functionalism interest groups¡]industrial elites¡^and political elites will affect the government attitudes in decision-making. The elite of automobile industry from both sides of Taiwan Straits press both governments to put the policy of ¡§three direct links¡¨ into practice, is the case in point.

Piezoelectric effect was discovered in the 19th century, but the applications of piezoelectric effect were realized until the 20th century. In this paper, piezoelectric actuators, which are made based on piezoelectric effect, are employed to establish a three-degree-of-freedom micro-manipulator. The mechanism of this micro-manipulator is designed as a parallel-type mechanism. The kinematics of the micro-manipulator is also analyzed. In addition, a remote control framework is implemented with a control system and this achievement can be a demonstration for future feasibility of application of this micro-manipulator to robotic systems.

The implicit function model is nowadays generally applied to a lot of fields that need 3D, such as computer game, cartoon or for specially effect film. So far, most hardware are still to support the polygon-mesh model but not implicit function model, so polygon-mesh model is still the mainstream of computer graphics. However, translation between the two representation models becomes a new research topic. This paper presents a new method to translate the triangles mesh model into the implicit functions model. The main concept is to use the binary space-partitioning tree to divide the points and patches in the triangle mesh model to create a hierarchical structure. For each leaf node in this hierarchical structure, we would generate a corresponding implicit function. These implicit functions are generated by the genetic algorithm. And the internal nodes in this hierarchical structure are blended by the blending operators. The blending operators make the surface become smooth and continual. The method we proposed reduces the data in a large amount because we only save the coefficients of the implicit surface. And the genetic algorithm can avoid the high computing complexity.

Since Bretton Woods System break down in year 1973. Many economists found that there are more similar business cycle between industrial countries. Recently, Doyle and Faust(2002) proposed the correlation of business cycle between two countries becomes weaker. Therefore in this search, we try to carry out two different aspect factor that effects the countries¡¦ business cycle correlation. The factor is so-called ¡§transmission mechanism.¡¨ Generally specking, Many empirical analysis have pointed out the temporary factors to the business cycle mainly come from the transferred factors of economic aspect. What is ¡§Transmission Mechanisms?¡¨ Economists often try to substitute it in good markets, financial markets, and the coordination of monetary policies. However, in this duration of the empirical analysis, using only these proxy variables to explain BCCs between two countries seems too limited. According to this situation, we believe if the BCCs can be explained by using proxy factors of non-economic variable, the result can be utilized by making up the defect. We attempt to find new factors in political approach and combine with the ¡§Transmission Mechanisms¡¨ that we have introduced earlier. To analyze further economic implication in our research, five conclusions have been summarized below: Firstly, increasing bilateral trade has significantly provided positive effect to BCCs among G7 countries from 1980 to 2002. Because bilateral trade intensity index is endogenous , we use exogenous variable as instrumental variable to estimate ¡§Trade¡¨. Secondly, we use Panel method to expand its matrix. Finally, we improve the empirical estimators of insignificant statistics before. So, when we talk about the relations between BCCs and good and service markets, we must consider these exogenous factors. Eventually, we will receive more detailed results. Secondly, although to trade in financial markets can increase the BCCs between two countries, the statistic report is insignificant . About this empirical result, we can obtain reasonable explanations from the researches (for instance: Imbs, 2004 or Kose et al, 2003), they point out that financial markets are bound excessively by globalization. Therefore, this will aggravatingly make each country to focus on its specialization. Finally, this situation will make the BCCs getting collapsed among these countries. This also explains that the specialization among these countries will reduce the positive effect from the BBCs to financial markets. Thirdly, in the research, the statistics effect of the trade intensity index and specialization are significant negative. It means that when good in transaction will result in more specialization. Two countries have similar industrial structure.Imbs(2004) consider the problem is the index we use to measure bilateral trade intensity. This index was effected from two countries¡¦ size . If use Clark and van Wincoop¡¦s trade intensity index to measure the effect, we can find that significant specialization by comparative advantage effect. Fourth, there are high level financial integration between two countries, because international risk sharing result in two countries have different industrial structure. Lastly, in the research, the statistics effect of the party variables and business cycle of correlations are very significant. This also indicates the political factor will play an important role for many sources of the fluctuation tread of BCCs. In other words, when we discuss the issue of BCCs if miss the contribution of political factors to the BCCs. Then, this might cause the omitted variable biased, and finally cause the whole computation become inefficient. In addition, we can have further discussion by an input of a factor: to conserve the joint benefit of all the member countries in an economic organization, these countries need to be ruled by the same ideal political party. Otherwise, the institute will never reach its essential result. Combining all the conclusions we have shown above, we can find out the BCCs among G7 countries from 1980-2002. Besides the influence of the ¡§Transmission Mechanisms,¡¨ the result will be varied by the political factors. In conclusion, we need to consider the contribution of the political party variables to the BCCs when talking about this issue, therefore; the original theoretical model can be more persuasive. According to a statistics of IMF, the BCCs among those industrial countries are falling little by little in recent years. Therefore, consolidating trade cooperation is essential for what we believe to improve the BCCs among G7. At the same time, pass through a strong integrate monetary policy can move forward all the incumbent parties from all the countries to agree among themselves, and even reach more substantial effect. From the example like this, we might find evidence from BCCs issues by discussing the integration process in European Monetary Union.

In this study, the fundamental mechanism of friction stir welding was investigated to establish the relationship among the three components of the forces acting on the work pieces, the variation of the stirring energy, and the joint characteristics of the materials. A dynamometer designed by Chiou et al., was used to measure the axial force (z-direction), the feed force (x-direction), and the clamping force (y-direction). The output energy of servo motor was monitored by power meter. Experimental results show that with increasing welding speed, the feed force increases obviously, the axial force increases slightly, and the energy almost remains constant for the fixed rotation speed of the spindle. At the rotation speed of spindle of 800 rpm, the spindle angle of 1¢X, the pre-clamping force of 2kN and the welding speed of 60 mm/min, results show that the feed force is about 1kN when the probe is plunged into the specimens but the shoulder does not be in contact with the surface of the specimen. However, when the probe is plunges into the specimens entirely and the shoulder is in contact with the surface slightly, the feed force is reduced to 0.48kN. Moreover, when the shoulder is in contact with the surface heavily, the feed force is reduced to 0.2kN. This result indicates that the contact force between the shoulder and the specimen causes the material to become soft and to backfill into the weld, and then decreases the feed force. After the specimen of the 6061-T6 aluminum has been welding, the micro hardness measurements are made. Results show that the distribution of the hardness is quite consistent along the welding as the feed force approaches to 0.2kN. Furthermore, the appearance on the surface of the weld is quite fine, and thereby it is able to get the high and uniform quality. The spacing distance of the weld surface can be theoretically analyzed. It is found that the spacing distance increases with welding speed and decreases with rotation speed of spindle. The theoretical predictions are in very good agreement with the experimental measurements.

No description available.

No description available.