Impulse Condition Research Articles

Optimizing the control of high ID movements: rethinking the obvious

An experiment was designed to determine the degree to which instruction and visual display influence participants' performance and control characteristics when executing difficult reciprocal aiming movements. Participants were randomly assigned to one of the three acquisition conditions (Fitts, Impulse and Sine). Participants in the Fitts condition were asked to flex/extend their limb/lever in the horizontal plane at the elbow joint (wrist stabilized) in an attempt to move back and forth between two targets as quickly and accurately as possible. In the Impulse condition, participants moved between two target lines paced by a metronome, and in the Sine condition, participants were asked to track a sine wave pattern. The timing for the Impulse and Sine conditions was set to result in total times (movement time+dwell time) similar to that observed in our previous experiments using the same Fitts conditions. The respective display and current position of the limb were projected on the screen in front of the participant. Following nine acquisition trials (15s each) under their assigned condition, Test 1 was conducted under the same conditions as the participant experienced during the acquisition, and then, Test 2 was conducted for all participants under the Fitts' conditions. The results for Test 1 indicated that total time and movement time for the three groups did not differ. However, dwell time was significantly lower, a larger proportion of movement time was spent in the acceleration portion of the movement, and peak velocity was significantly lower for the participants in the Sine condition than for participants in the Fitts condition. On Test 2, where Fitts conditions were imposed, the Sine group outperformed the Fitts condition on all variables except hits and endpoint variability where the Fitts and Sine groups performed similarly.

Self-Integrating Rogowski Coil for High-Impulse Current Measurement

This paper presents the operating principle, the performance under impulse condition, and the design of a self-integrating Rogowski coil for measuring high-impulse currents. Oscillatory and overdamped unidirectional impulse currents are generated up to 10 kA and measured by different methods, namely, two commercial impulse current transformers, a resistive shunt, and the newly designed self-integrating Rogowski coil. For the resistive method, the voltage drop across the shunt affects the total voltage measured across the test object and causes distortion in the case of simultaneous measurement by an impulse current transformer having a small aperture. The Rogowski coil theory under impulse current conditions is presented. The concept of transmission lines is used, and the line parameters are optimized to achieve a self-integrating mode and avoid spurious effects of reflections and stray capacitances. The output voltage linearity of the designed self-integrating Rogowski coil is checked using different linear and nonlinear loads and coil termination resistances. It is found that at a termination resistance of 1 ?, satisfactory impulse current waveforms are measured by taking the commercial impulse current transformer as a reference signal. Results reveal that the measurement errors for the current peak and front and tail times are ±2%, ?6%, and ? 12%, respectively. Overdamped impulse currents are generated by different generator capacitances, where comparisons between the measured and calculated current waveform parameters have shown good agreement.

부탄을 액화 연료로 사용한 냉가스 추진 시스템에 대한 연구

소형 인공위성의 전형적인 추진 시스템인 냉가스 추진 시스템에 액화 연료를 직접 적용하여 성능을 분석하였다. 고려하는 액화 연료 냉가스 추진 시스템과 일반적으로 사용되는 질소 추진 시스템의 성능을 비교하였다. 질소 추진 시스템과 동일한 질량 조건, 동일한 부피 조건, 동일한 총 임펄스 조건에서 각각 액화 연료를 사용한 냉가스 시스템의 성능과 필요한 연료 탱크의 부피, 필요한 추진 시스템의 질량을 산출하였다. 액화 연료를 사용한 냉가스 추진 시스템은 일반적인 질소 추진제를 사용한 시스템보다 성능, 부피 및 질량 등에서 많은 이점을 가지며 냉가스 추진 시스템에 직접적으로 적용이 가능함을 알 수 있었다. A direct application of liquefied gas propellants to a typical small satellite cold gas propulsion system was analyzed. Performance of systems using liquefied gas propellant under consideration was compared to that of a nitrogen cold gas propulsion system. Liquefied gas propellant propulsion system's performance, required tank volume, and required propulsion system mass has been calculated at the same mass, volume, and total impulse condition of a typical nitrogen cold gas propulsion system. It was found that the liquefied gas propulsion system has advantages in performance, volume, and mass, compared to a typical nitrogen cold gas system, and can be directly applied to a cold gas propulsion system.

Mechanism of discharge development in SF6 with and without spacers under fast oscillating impulse condition

This paper describes the mechanism of leader discharge inception in SF6 gas with and without spacers exposed to fast oscillating impulse. A photomultiplier and a current probe are employed for the investigation of discharge development. The results show that the back discharge plays an important role in the initiation and the further development of the leader discharge along the spacer surface in the presence of fast oscillating impulses. In the case of SF6 gap, the steepness of impulse plays a notable role in the extension of the streamer from which the leader discharge is triggered.

A State Space Method for Modal Identification of Mechanical Systems from Time Domain Responses

A new state space method is presented for modal identification of a mechanical system from its time domain impulse or initial condition responses. A key step in this method is the identification of the characteristic polynomial coefficients of an adjoint system. Once these coefficients are determined, a canonical state space realization of the adjoint system and the system′s modal parameters are formulated straightforwardly. This method is conceptually and mathematically simple and is easy to be implemented. Detailed mathematical treatments are demonstrated and numerical examples are provided to illustrate the use and effectiveness of the method.

The World Inhospitable to Levinas

All great thinkers create powerful concepts and/or images of their own but as a rule design them together with a complete universe to accommodate them and infuse them with sense. For Emmanuel Levinas, world he constructed was the of which was self-consciously a utopia in both of its inseparable senses (i.e., of no place and good place). The of two was primal scene of morality, test-tube in which selves germinate and sprout. It was also only stage on which such selves could play themselves, i.e., as beings, instead of playing scripted roles and reciting someone else's lines. The primal scene of morality is realm of face-to-face, of tremendous encounter with Other as a Face. Morality, which in Levinas' terms referred to being for Other, has a notoriously awesome potential for love and hatred, for self-sacrifice and domination, care and cruelty. Ambivalence is its prime mover. And yet of two is capable of sustaining universe on its own. In this morality does not need codes or rules, reason or knowledge, argument or conviction. It would not understand them anyway; morality is all that (one cannot even say that impulse is ineffable or mute since ineffability and dumbness come after language). The impulse triggered by Face precedes speech. It sets its standards as it goes. It does not know guilt or innocence. It is pure in only true sense of purity, purity of naivety. As Vladimir Jankelevitch has pointed out, one cannot be pure except under condition of not having purity, that is to say of not possessing it knowingly.1 The moral of postulated by Levinas as birth-home and homeland of morality, is naive; it does not know (has not been told) that it is a let alone a one. Only when gazed upon from outside, does congeal into a couple, a pair, a they out there. It is outside gaze that objectifies and thus makes it into a unit, a thing that can be described as it is, handled, compared with others it, assessed, evaluated, and ruled on. But from point of view of me as a self there is no we, no couple, no supraindividual entity with its and rights. Inside there is just me, with my responsibility, with my care, with command that commands me and me alone, and there is Face, catalyst and midwife. My togetherness with Other won't disappearance or opting out of myself or Other. There would be nothing left to survive that disappearance. Togetherness in moral party is vulnerable, weak, fragile, and lives precariously with a shadow of death never far away and all this because neither I nor Other is replaceable. It is precisely this non-replaceability that makes our togetherness moral. Because each of us is irreplaceable, it makes no sense to think of actions in terms of interests. There is no way in which actions of either of us could be classified as egoistic or altruistic. Good can be seen only in its opposition to evil. How can one say inside a in which no one is replaceable, that what is good for one partner may be bad for another? It is inside such a moral moral of that my responsibility cannot be fathomed and fulfilled; it feels unlimited and becomes a whole life responsibility. It is under this condition that command needs no argument to gain authority, nor support of a threat of sanctions. It feels like a command, and an unconditional command at that. But all this changes with appearance of Third. Now, true society appears, and naive, unruled, and unruly impulse, simultaneously necessary and sufficient condition of moral party, does not suffice any more. The Moral Party Broken Into In society, unlike in universe of two, Levinas ' postulate of putting ethics before ontology sounds odd. …

Influence of molecular structure on the propagation of streamer discharge in dielectric liquids

Prebreakdown phenomena in dielectric liquids which have various molecular structure are observed in detail for point-to-plane electrode configuration under an impulse voltage condition. Experiments are carried out by using a high-speed schlieren photography and a current measurement system by LED simultaneously.

Cavitation erosion of austenitic stainless steel and effect of boron and nitrogen ion implantation

An austenitic stainless steel subjected to cavitation vortex undergoes impulse loading condition characterized by the localized pulses of variable amplitudes distributed randomly over the exposed area. These pulses are able to form craters or sunken areas of 10–30 μm diameter. Accumulation of these impacts promotes surface hardening, local fracture, crack propagation and subsequently erosion which is initiated inside the grains at the protruding slip bands and twin boundaries. The boron and nitrogen ion implantation of various fluences showed no significant effects on erosion occurence of this alloy contrary to what has been reported in the literature. In implanted specimens, erosion starts with brittle fracture of surface from the grain boundaries and extends inside the grains. Induced subsurface microstructures consist essentially of dislocation loops, deformation twins and martensite platelets. Concentration of straight and parallel dislocations appear at deeper layers. All these deformation features are explained as necessary to the high work hardening under high strain rate deformation and triaxial loading condition of impacts.

Electric responses of the cerebral cortex to central excitation and inhibition

An attempt was made to evaluate critically the extent to which the background electrocorticogram, neuronal impulse activity, and evoked potentials reflect the state of cortical excitation and inhibition. It was shown that during electrocorticogram desynchronization, firing neurons predominated in the surface (mainly afferent) layers, while inhibited neurons were in the majority in the lower layers of the cortex. Consequently, desynchronization does not reflect diffuse excitation of the cortex and cannot be taken as an index of central excitation. Slow electrocortical waves cannot be used as indicators of an inhibitory state, even though they may be associated with processes leading to the development of inhibition. Under the effects of different stimuli, the number of neurons participating in impulse condition, and the number of neurons temporarily inhibiting impulse activity in the projection cortical area were stable (ratio 2:1). It was found that the correlation between impulse discharges of neuronal pairs increases during both central excitation and central inhibition. Nonetheless, differences between cortical excitation and inhibition were seen in the reorganization of neuronal columns. The use of evoked potentials to determine cortical excitation or inhibition is complicated by the fact that the amplitude of evoked-potential components reflects the divergent influences of many factors. It was shown that conditional excitation diminished the evoked potential to a light stimulus in the projection cortical area, but caused it to increase in the region of the motor analyzer. The elaboration of a conditional inhibition (extinction) is accompanied by the growth of an evoked potential to a stimulus in the primary cortical area, and by its repression in the region of the motor analyzer. In this case, a large delayed negative wave appears in the evoked potential.