1,842 research outputs found
Fractal model and Lattice Boltzmann Method for Characterization of Non-Darcy Flow in Rough Fractures.
The irregular morphology of single rock fracture significantly influences subsurface fluid flow and gives rise to a complex and unsteady flow state that typically cannot be appropriately described using simple laws. Yet the fluid flow in rough fractures of underground rock is poorly understood. Here we present a numerical method and experimental measurements to probe the effect of fracture roughness on the properties of fluid flow in fractured rock. We develop a series of fracture models with various degrees of roughness characterized by fractal dimensions that are based on the Weierstrass-Mandelbrot fractal function. The Lattice Boltzmann Method (LBM), a discrete numerical algorithm, is employed for characterizing the complex unsteady non-Darcy flow through the single rough fractures and validated by experimental observations under the same conditions. Comparison indicates that the LBM effectively characterizes the unsteady non-Darcy flow in single rough fractures. Our LBM model predicts experimental measurements of unsteady fluid flow through single rough fractures with great satisfactory, but significant deviation is obtained from the conventional cubic law, showing the superiority of LBM models of single rough fractures
KINEMATICS ANALYSIS OF THE LOWER EXTREMITY DURING THE TWO-HANDED BACKHAND GROUNDER STROKE AND DRIVE VOLLEY FOR TENNIS PLAYERS
The purpose of this study was to discuss the motion characteristics of the X-Factor and the role of stance positioning on backhand tennis swing in drive volley and ground stroke. Three elite female tennis players which are training more than 20 hours per week participated in this study. Motion Analysis System with 10 Eagle Digital inferred high speed cameras at 200Hz were used for this study. This study found that the pre-impact rotation mode did not have consistent pattern, but similar trend can be found between the strokes, with the square timing was close at the impact and more trunk rotations on ground stroke in the follow through In the pre-impact stance setting, the ground stroke will adopt a more closed stance, which may be helpful for the hip joint activity. It is suggested that future studies may increase the parameters of the hip joint to establish the reasons for this technical difference
KINEMATICS ANALYSIS OF THE UPPER EXTREMITY DURING THE TWOHANDED BACKHAND DRIVE VOLLEY FOR FEMALE TENNIS PLAYERS
The purpose of this study was to discuss the motion characteristics of the arms in the two-handed backhand drive volley. Five elite female tennis players participated in this study, their two-handed backhand drive volley strokes were analysed, and all participants are right handed. Motion Analysis System with 10 Eagle Digital inferred high speed cameras at 200Hz were used for this study. The results show a similar elbow and wrist speed strategy in x-axis between two-handed ground stroke and drive volley, our study also found that the rear arm dominates the stroke and mainly provide the topspin that is required for the skill of the drive volley. In order to create better stroke efficiency, the right elbow reached peak velocity first, followed by the right wrist before racket impact with the ball
JOINT MOBILIZATION CHANGES ACTIVATIONS IN GLUTEUS AND VASTI MUSCLES DURING FUNCTIONAL ACTIVITIES IN PEOPLE WITHOUT AND WITH PATELLOFEMORAL PAIN SYNDROME
We aimed to examine whether patellofemoral joint mobilization altered the activation in vasti and gluteus muscles in people with and without PFPS during functional activities. A total of 40 young collegiate students with and without PFPS were recruited. After the intervention of patellofemoral joint mobilization, there were significant earlier activations of vasti muscles and delayed activation of gluteus muscles such as heel rise, step up and down and drop landing in people with PFPS compared to that of healthy controls (
THE CORRELATION OF GOLF PUTTING CLUB HEAD VELOCITY AND GRIP FORCE FOR EACH PHASE
We investigate the correlation of golf putting club head velocity and grip force in different phases during the putting stroke. Five elite college players (handicap: 2~8) executed a putt as accurately as possible to reach a target distance of 12ft. The Novel System and were used to measure the grip force and club head velocity. The lowest club head velocity and grip force both occurred at address up to the top of backswing (phase I). The club head velocity and grip force started increasing during the downswing and reached its peak before impact (phase II), and decreased after impact to finish (phase III). The mean club head velocity and grip force for Phase I, II, III in order are 0.33m/s, 0.92m/s, 0.87m/s; 28.09N, 54.77N, 50.76N. Club head velocity was significantly correlated to grip force in phase II and III (r=0.937; r=0.866). The similar variation pattern of club head speed and grip force may give better control to the putter during the impact and produce more consistent putting stroke
1,3-Bis(4-methoxybenzyl)-6-methylpyrimidine-2,4(1H,3H)-dione
The title compound, C21H22N2O4, was prepared by reaction of 6-methylpyrimidine-2,4(1H,3H)-dione and 1-chloromethyl-4-methoxybenzene. In the title molecule, the central pyrimidine ring forms dihedral angles of 62.16 (4) and 69.77 (3)° with the two benzene rings. In the crystal, weak intermolecular C—H⋯O hydrogen bonds link the molecules into chains
DISTRIBUTION OF GRIP PRESSURE THROUGHOUT THE PHASES OF PUTTING IN ELITE GOLF COLLEGE PLAYERS
The purpose of this study is to investigate the distribution of grip pressure, force and the peak pressure of different phases during the putting stroke. Five elite college players with handicaps of 2-8 participated in the study. The Novel Pliance-x System and 150Hz 8- camera Motion Analysis Corporation System were used to collect grip pressure and identify each phase of the putting stroke. At each phase of the putting stroke, average grip pressure, peak pressure and grip force were investigated. Results indicated that lowest grip pressure occurred at address up to the top of backswing (2.41±1.36 Kpa). Grip pressure started to increase during the downswing and reached its peak, 0.02±0.05s, before impact (4.70±1.97 Kpa). The pressure reduced again after impact (4.36±2.06 Kpa). Results indicate that grip pressure does not remain the same throughout the stroke
Rapid automatic naming and phonological awareness deficits in preschool children with probable developmental coordination disorder
Children with developmental coordination disorder (DCD) have been reported to have a higher risk of dyslexia than children with typical development (TD). Phonological awareness (PA) and rapid automatic naming (RAN) are known to be predictive of children’s reading development. The present study examined PA and RAN in preschool children with and without probable DCD in Taiwan. In total, 704 children aged 5–6 years old from 25 preschools in Taichung City were included as participants. The probable DCD children performed more poorly than the children with TD on the PA and the RAN tests. Put in deficit terms, 22% of the children with TD, but 48% of the probable DCD children, had a single or dual PA/RAN deficit. Furthermore, it was manual dexterity that bore the unique relationship with RAN. Automatic visual perceptual-motor coordination may be the common processing component that underlies RAN and probable DCD. The early visual perceptual-motor profile of probable DCD children has not been well recognized before
Comprehensive Genome Analysis on the Novel Species Sphingomonas panacis DCY99(T) Reveals Insights into Iron Tolerance of Ginseng
Plant growth-promoting rhizobacteria play vital roles not only in plant growth, but also in reducing biotic/abiotic stress. Sphingomonas panacis DCY99(T) is isolated from soil and root of Panax ginseng with rusty root disease, characterized by raised reddish-brown root and this is seriously affects ginseng cultivation. To investigate the relationship between 159 sequenced Sphingomonas strains, pan-genome analysis was carried out, which suggested genomic diversity of the Sphingomonas genus. Comparative analysis of S. panacis DCY99(T) with Sphingomonas sp. LK11 revealed plant growth-promoting potential of S. panacis DCY99(T) through indole acetic acid production, phosphate solubilizing, and antifungal abilities. Detailed genomic analysis has shown that S. panacis DCY99(T) contain various heavy metals resistance genes in its genome and the plasmid. Functional analysis with Sphingomonas paucimobilis EPA505 predicted that S. panacis DCY99(T) possess genes for degradation of polyaromatic hydrocarbon and phenolic compounds in rusty-ginseng root. Interestingly, when primed ginseng with S. panacis DCY99(T) during high concentration of iron exposure, iron stress of ginseng was suppressed. In order to detect S. panacis DCY99(T) in soil, biomarker was designed using spt gene. This study brings new insights into the role of S. panacis DCY99(T) as a microbial inoculant to protect ginseng plants against rusty root disease
6-Benzyloxy-2-phenylpyridazin-3(2H)-one
In the title compound, C17H14N2O2, the central pyridazine ring forms dihedral angles of 47.29 (5) and 88.54 (5)° with the benzene rings, while the dihedral angle between the benzene rings is 62.68 (6)°. In the crystal, molecules are linked by two weak C—H⋯O hydrogen bonds and three weak C—H⋯π interactions
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