12,134 research outputs found
The effect of total knee arthroplasty on joint movement during functional activities and joint range of motion with particular regard to higher flexion users
Study aimed to evaluate active and functional knee excursion of patients before and after total knee arthroplasty (TKA) and to determine whether TKA restores quality of life related to functional activities of daily living. Found that although TKA offers excellent pain relief and contributes to the overall well-being of the patient, these results suggest that it also leads to a reduced range of active and functional motion in the majority of patients. This is associated with a lower-than-normal physical quality of life. The design of implants and rehabilitation programmes should be reconsidered so that better range of motion and quality of life can be achieved for patients
Preoperative predictors of knee range of motion during stair walking after total knee replacement
This paper discusses the preoperative predictors of knee range of motion during stair walking after total knee replacement. It was presented at the 17th Annual Meeting of the European Society of Movement Analysis for Adults and Children (ESMAC) in 2008
Control of macrophytes by grass carp (ctenopharyngodon idella) in a Waikato drain, New Zealand
Hornwort (Ceratophyllum demersum L.) and other aquatic macrophytes have historically been mechanically removed from the Rangiriri drain and Churchill East drain to maintain drain efficiency. As an alternative control method for the high plant biomass that accumulates at the end of summer, the effect of stocking diploid grass carp (Ctenopharyngodon idella L.) on the aquatic vegetation was evaluated in these Waikato drainage systems. At the start of the trial, both drains had a low diversity of aquatic macrophytes, and of the nine species (including the emergents), seven were exotic. Two months after grass carp were released to Churchill East drain (the treated drain) the four submerged and floating macrophyte species became scarce in the main drain. Over the same period, these species increased in biomass in Rangiriri drain (the untreated drain), where hornwort became dense and surface-reaching and remained so for the duration of the trial. However, grass carp did not control submerged vegetation in smaller side drains or the shallow, upper parts of the main drain, or the marginal sprawling species and emergent species. The cost of leasing the grass carp was similar to the cost of clearing the drains mechanically, but grass carp provided continuous weed control. However, subsequent to this trial, 62 dead grass carp were found in Churchill East drain in February 2001, and weed cover subsequently increased. This illustrates that grass carp management in New Zealand agricultural drains can be problematic due to periodic fish kills
Erosion/corrosion of turbine airfoil materials in the high-velocity effluent of a pressurized fluidized coal combustor
Four candidate turbine airfoil superalloys were exposed to the effluent of a pressurized fluidized bed with a solids loading of 2 to 4 g/scm for up to 100 hours at two gas velocities, 150 and 270 m/sec, and two temperatures, 730 deg and 795 C. Under these conditions, both erosion and corrosion occurred. The damaged specimens were examined by cross-section measurements, scanning electron and light microscopy, and X-ray analysis to evaluate the effects of temperature, velocity, particle loading, and alloy material. Results indicate that for a given solids loading the extent of erosion is primarily dependent on gas velocity. Corrosion occurred only at the higher temperature. There was little difference in the erosion/corrosion damage to the four alloys tested under these severe conditions
An exactly solvable model of a superconducting to rotational phase transition
We consider a many-fermion model which exhibits a transition from a
superconducting to a rotational phase with variation of a parameter in its
Hamiltonian. The model has analytical solutions in its two limits due to the
presence of dynamical symmetries. However, the symmetries are basically
incompatible with one another; no simple solution exists in intermediate
situations. Exact (numerical) solutions are possible and enable one to study
the behavior of competing but incompatible symmetries and the phase transitions
that result in a semirealistic situation. The results are remarkably simple and
shed light on the nature of phase transitions.Comment: 11 pages including 1 figur
Measuring risky-driving propensity in pre-drivers: The Violation Willingness Scale
There is a growing recognition that the antecedents of risky driving attitudes can be traced to the pre-driving period. Few measures of driving-specific risk taking aimed at pre-drivers (defined here as those who are not permitted to drive independently) have been validated, however, meaning our understanding of the development of risky driving attitudes is limited. This paper reports the construction of a self-report Violation Willingness Scale (VWS) for pre-drivers, examination of the existing Attitudes to Driving Violations Scale (ADVS) in pre-drivers and some preliminary data on the development of propensity to risky driving. Study One found that the VWS and ADVS had strong psychometric properties in a sample of pre-drivers aged 16â19 years of age. Study Two found the VWS and ADVS showed moderate to strong and somewhat independent relationships with a number of existing measures of risky driving behaviour in a sample of fully licensed drivers (age range 18â65 years). This evidence supports the ADVS and VWS as valid tools to measure the propensity to risky driving in pre-drivers. We also discuss preliminary evidence on the relationship between propensity to risky driving and stage of driver training and experience, which indicates that willingness to commit most violations diminishes with driving experience while attitudes and willingness to speed become riskier
The erosion/corrosion of small superalloy turbine rotors operating in the effluent of a PFB coal combustor
Superalloy turbine rotors in a single stage turbine with 6 percent partial admittance were operated in the effluent of a pressurized fluidized bed coal combustor for up to 164 hours. Total mass flow was 300 kg/hr and average particulate loadings ranged from 600 to 2800 ppm for several coal/sorbent combinations. A 5.5 atm turbine inlet gas pressure and inlet gas temperatures from 700 to 800 C yielded absolute gas velocities at the stator exit of about 500 m/s. The angular rotation speed (40,000 rpm) of the six inch diameter rotors was equivalent to a tip speed of about 300 m/s, and average gas velocities relative to the rotating surface ranged from 260 to 330 m/s at mean radius. The rotor erosion pattern reflects heavy particle separation with severe (5 to 500 cm/yr) erosion at the leading edge, pressure side center, and suction side trailing edge at the tip. The erosion distribution pattern provides a spectrum of erosion/oxidation/deposition as a function of blade position. This spectrum includes enhanced oxidation (10 to 100 x air), mixed oxides in exposed depletion zones, sulfur rich oxides in deposition zones, and rugged areas of erosive oxide removal
Classical mappings of the symplectic model and their application to the theory of large-amplitude collective motion
We study the algebra Sp(n,R) of the symplectic model, in particular for the
cases n=1,2,3, in a new way. Starting from the Poisson-bracket realization we
derive a set of partial differential equations for the generators as functions
of classical canonical variables. We obtain a solution to these equations that
represents the classical limit of a boson mapping of the algebra. The
relationship to the collective dynamics is formulated as a theorem that
associates the mapping with an exact solution of the time-dependent Hartree
approximation. This solution determines a decoupled classical symplectic
manifold, thus satisfying the criteria that define an exactly solvable model in
the theory of large amplitude collective motion. The models thus obtained also
provide a test of methods for constructing an approximately decoupled manifold
in fully realistic cases. We show that an algorithm developed in one of our
earlier works reproduces the main results of the theorem.Comment: 23 pages, LaTeX using REVTeX 3.
Analytically solvable potentials for -unstable nuclei
An analytical solution of the collective Bohr equation with a Coulomb-like
and a Kratzer-like unstable potential in quadrupole deformation space
is presented. Eigenvalues and eigenfunctions are given in closed form and
transition rates are calculated for the two cases. The corresponding
SO(2,1)SO(5) algebraic structure is discussed.Comment: 9 pages, 4 figures in one .ps fil
Hydrogen Flare Stack Diffusion Flames - Low and High Flow Instabilities, Burning Rates, Dilution Limits, Temperatures, and Wind Effects
Combustion characteristics and safety factors for hydrogen diffusion flames in flare stack operation
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