Use Of Transient Techniques Research Articles

Comparación de complicaciones asociadas con el uso de placas en 8 y tornillos canulados para la corrección de deformidades angulares

BackgroundThe epiphysiodesis and hemiepiphysiodesis for correction of angular deformities in the lower limbs has evolved over time and today the use of transient techniques is preferred like are cannulated screws and eight plates. The aim of the study was to compare the outcome of patients with angular deformities treated with cannulated screws and eight shaped plates techniques and determine if there are differences in the outcome of patients. MethodsA prospective cohort study was performed including pediatric patients treated at the Instituto de Ortopedia Infantil Roosevelt (IOIR) for angular deformities in their lower limbs from 2010 to 2012. A paired comparable cohort of patients in age, sex and diagnosis were assessed in their outcomes. For group 1 (eight shaped plate patient cohort) and group 2 (cannulated screws patient cohort) we evaluated the presence of pain, antalgic limp, edema, infection and inability to fully support lower limbs and crutches requirements. Results6-month postoperative follow-up was performed. It was found in the assessments made in the first month of monitoring the presence of pain in 10 patients for group 1 and in 2 patients for group 2 (p<0.05). We found that the antalgic limp, swelling, infection and inability to support have no statistically significant differences in the study group. DiscussionThe use of eight shaped plates is associated with the presence of increased pain in the immediate postoperative period in some patients, but this review suggests that a medium-term pain improvement is seen in this group of patients, therefor not affecting the final clinical outcome. Evidence levelIII.

Application of the network simulation method to study the electrical response of ion-exchange membrane systems to pulsed electric fields

The transient electrical response of an ion-exchange membrane system to square shaped electric perturbations not only when the electric potential is the externally controlled variable but also when an electric current is imposed through the system, has been simulated using the network simulation method. The system under study is constituted by a cation-exchange membrane in which the fixed-charge is homogeneously distributed in space and two diffusion boundary layers on both sides of the membrane, the electric double layers at the interfaces being included. The time evolution of the counterion flux exiting from the system in response to a pulsed electric potential has been analyzed in order to establish the conditions in which the use of transient techniques in ion-exchange membranes can lead to intensification of the efficiency of electrodialysis. Also, the time evolution of the system electric potential in response to a pulsed electric current is analyzed and discussed. The counterion quantity exiting from the system and the energy consumption in pulse mode are evaluated and compared to those obtained from stationary electrodialysis.

Network simulation of the electrical response of ion-exchange membranes with fixed charge varying linearly with position

The steady-state and transient electrical properties of ion-exchange membrane systems with fixed charge distributions varying linearly with position inside the membrane have been investigated using the network simulation method, including the diffuse double layer effects. A network model for the Nernst–Planck and Poisson equations has been used to describe the ionic transport processes through an inhomogeneous cation-exchange membrane and the two diffusion boundary layers on both sides of the membrane. With this model and the electric circuit simulation program PSpice, the steady-state and transient responses of the system to an externally applied electric potential difference have been simulated. The steady-state current–voltage characteristic of the whole membrane system and the equilibrium and steady-state non-equilibrium profiles of the ionic concentrations, the electric potential and the electric charge density across the system, have been analyzed. The responses of the system to a step-function potential (chronoamperometric response) and to a square shaped periodic potential, have also been obtained. The time evolution of the counterion flux exiting from the system has been analyzed in order to establish the conditions in which the use of transient techniques in inhomogeneous ion-exchange membranes can lead to intensification of the efficiency of membrane processes such as electrodialysis.

Use of isotopic transient techniques in the study of NO reduction reactions

Examples of the use of transient techniques in NO reduction reactions are presented. The specific reactions studied are NO + NH 3 reaction over crystalline vanadia catalysts and NO + CH 4 reaction over Pd/TiO 2 catalysts. The reactions were investigated by the following step function changes: 14NH 3 + O 2 → 15NH 3 + O 2, 14NO + NH 3 + O 2 → 15NO + NH 3 + O 2, 14N 16O → 15N 18O, 13CH 4 + NO → NO, 13CH 4 + NO → He, 13CH 4 → NO, CH 4 + 15NO → CH 4, and CH 4 + 15NO → NO + CH 4. The results have provided information about the differences in the surface residence time of intermediates while also making it possible to differentiate between different reaction pathways in the NO reduction reactions with ammonia and with methane.

Use of transient techniques in the study of electrocrystallisation in the reduction of Cu+ ions in fused LiCl + KCl

Use of transient techniques in the study of electrocrystallisation in the reduction of Cu+ ions in fused LiCl + KCl

Use of transient techniques in the study of electrocrystallisation in the reduction of Cu + ions in fused LiCl+KCl

Transient electrochemical methods are applied in the study of the early stages of copper deposition on inert electrodes of vitreous carbon or graphite from a solution of Cu + in fused LiCl−KCl. The rising current transient resulting from the three-dimensional electrochemical nucleation is related to the number density of surface nuclei in terms of diffusion of metal ions towards isolated growing hemispheres. In this approach the diffusion coefficient of Cu + ions deduced from other independent measurements (capillary technique with radioactive tracers) is used. The kinetics of nucleation of the metal deposit are described for potentiostatic and galvanostatic conditions. The overvoltage required for the growth of stable nuclei is examined as a function of nucleus size and of interfacial energy. It is shown that the surface properties of the electrode material may have a catalytic effect on the nucleus creation.

Electromagnetic methods in applied geophysics

Applied electromagnetic research in recent years has been influenced by the growing importance of geothermal energy, coal, and permafrost, in addition to the traditional area of minerals. The interest in near-insulators such as coal and ice encouraged development of radars and other VHF-UHF techniques. Interpreting such measurements required reliable physical properties data for those materials over a frequency range of 6–10 decades. The utility of the high frequency field data has been improved through the use of transient techniques for data acquisition, and data processing schemes similar to those used in reflection seismology. The major developments in the more usual frequency range of applied geophysics (30 Hz—3 kHz) have also dealt with transients. In certain circumstances they appear to have a fundamental sensitivity not readily obtained by discrete frequency methods. Computer modelling of 3-D problems is progressing slowly. Improved 2-D inversion programs are in use, but their capabilities are very limited. Superconductivity plays a role in several new instrument developments. SQUIDs, and SQUID gradiometers have improved considerably since the last Workshop. Robust SQUID magnetometers having noise levels of $$10^{ - 5} - 10^{ - 6} nT/\surd Hz$$ can now be obtained commercially. Gradiometer sensitivities have improved accordingly. A superconducting loop 3 metres in diameter, to be test flown early in 1979, is the prototype of a new low frequency system to map conductivity from a helicopter. It is expected to have greater depth penetration in conductive terranes than the best existing systems, because of the low frequency and anticipated low system noise. A new magnetotelluric procedure, using a remote field reference, reduced the scatter in apparent resistivities and other response functions to a few percent. Further improvements must now be made in modelling and interpreting MT results if we are to benefit from this development.

Transient testing of loudspeakers

Recent interest in the use of transient techniques to test loudspeakers springs from the inadequacy of the steady‐state pressure response to specify completely the behavior of a loudspeaker. Tone bursts have shown some promise as a useful type of electrical signal to excite loudspeakers for transient testing. It appears, however, that Heavyside's step function or Carson's unit impulse function (the delta‐function) may reveal more directly the significant characteristics of a loudspeaker. The response of loudspeakers to each of these latter functions has been examined and typical radiation spectra have been determined experimentally. The results of these analyses seem to yield a substantial amount of useful information about the performance of loudspeakers.

Transient Testing of Loudspeakers

Recent interest in the use of transient techniques to test loudspeakers springs from the inadequacy of the steady-state pressure response to specify completely the behavior of a loudspeaker. Tone bursts have shown some promise as a useful type of electrical signal to excite loudspeakers for transient testing. It appears, however, that Heavyside's step function or Carson's unit impulse function (the delta-function) may reveal more directly the significant characteristics of a loudspeaker. The response of loudspeakers to each of these latter functions has been examined and typical radiation spectra have been determined experimentally. The results of these analyses seem to yield a substantial amount of useful information about the performance of loudspeakers.