RECENT DEVELOPMENTS IN ELTRAN PROSPECTING

Geophysics ◽  
1939 ◽  
Vol 4 (4) ◽  
pp. 283-291 ◽  
Author(s):  
Paul W. Klipsch
Keyword(s):  
Time Constant ◽  
Wave Form ◽  
Simple Circuit ◽  
Wave Shape ◽  
Simplified Method ◽  
Recent Developments ◽  
Standard Value ◽  
Standard Wave ◽  
Straight Lines ◽  
Opposing Wave

Early difficulties encountered relative to measuring the wave form of the detected potential by means of a predistorted opposing wave have been eliminated by introducing several novelties. These comprise a new mixing circuit, novel means for synchronizing the opposing wave with the detected wave, and simplified predistorting networks. A calibration scheme is outlined to maintain the detection apparatus at a constant level of performance. A simplified method of measuring the detected wave form obviating the synthetic opposing wave, useful in certain areas, is shown. Essentially it comprises subjecting the detected wave to the further distorting action of a simple circuit, the adjustment of which produces a standard wave shape consisting of straight lines in the oscilloscope. The adjustment of this circuit necessary to bring the wave shape to this standard value constitutes the measure of the time constant of the detected wave.

Vibratory Feeding by Nonsinusoidal Vibration—Optimum Wave Form

1985 ◽  
Vol 107 (2) ◽  
pp. 188-195 ◽  
Author(s):  
S. Okabe ◽  
Y. Kamiya ◽  
K. Tsujikado ◽  
Y. Yokoyama
Keyword(s):  
Experimental Results ◽  
Wave Form ◽  
Velocity Wave ◽  
The Mean ◽  
Straight Lines ◽  
Vibratory Conveyor ◽  
Theoretical Results ◽  
Vibratory Feeding

This paper presents the conveying velocity on a vibratory conveyor whose track is vibrated by nonsinusoidal vibration. The velocity wave form of the vibrating track is approximated by six straight lines, and five distortion factors of the wave form are defined. Considering the modes of motion of the particle, the mean conveying velocity is calculated for various conditions. Referring to these results, the optimum wave form is clarified analytically. The theoretical results show that the mean conveying velocity is considerably larger than that of ordinary feeders if the proper conveying conditions are chosen. The theoretical results are confirmed by experimental results.

scholarly journals A Single Phase Sinusoidal Current Inut Converter without Sinusoidal Standard Wave Form.

1994 ◽  
Vol 114 (6) ◽  
pp. 654-661 ◽  
Author(s):  
Yasuo Notohara ◽  
Motoo Futami ◽  
Kazuo Tahara ◽  
Tsunehiro Endoo ◽  
Koojiroo Yamashita
Keyword(s):  
Single Phase ◽  
Wave Form ◽  
Sinusoidal Current ◽  
Standard Wave

Photorefractive Polymers With High Speed

1999 ◽  
Vol 561 ◽  
Author(s):  
N. Peyghambarian ◽  
K. B. Ferrio ◽  
J. A. Herlocker ◽  
E. Hendrick ◽  
B. D. Guenther ◽  
...  
Keyword(s):  
Time Constant ◽  
High Speed ◽  
Response Rates ◽  
Rapid Progress ◽  
New Materials ◽  
Photorefractive Polymers ◽  
Recent Developments ◽  
Photorefractive Polymer ◽  
Grating Formation

ABSTRACTRapid progress in photorefractive polymers includes new materials with improved response rates. We briefly review recent developments in this rapidly evolving area and report grating formation with a 2-millisecond time-constant, the fastest reported to date in any photorefractive polymer.

scholarly journals The Wave Form of Luminescence Emitted by Noctiluca

1967 ◽  
Vol 50 (9) ◽  
pp. 2211-2237 ◽  
Author(s):  
Roger Eckert
Keyword(s):  
Time Course ◽  
Short Interval ◽  
Analogue Computer ◽  
Wave Form ◽  
Conduction Time ◽  
Wave Shape ◽  
Intensity Maximum ◽  
Light Reaction ◽  
First Order

The wave shape, intensity, and time course of the flash were examined with the aid of electronic operations in order to characterize the luminescence response and examine the in vivo dynamics of the light reaction. The most prominent single component of the flash shape is its exponential decay, beginning several milliseconds after the intensity maximum, with a mean rate constant at 23°C of -0.088 msec-1. Earlier components of the flash curve are more complex, exhibiting no pure exponentials with time. As predicted from previous observations, the time course of the flash triggered by a propagated action potential, and therefore influenced by the conduction time of the triggering potential, is measurably slower than that of the synchronously triggered flash. The time course of emission from individual specimens is otherwise quite stable, undergoing only limited slowing with short-interval fatigue or specimen deterioration in spite of marked changes in the amplitude of the wave form. Relative stability of amplitude is obtained when flashes are elicited at regular intervals greater than 10 sec. On the basis of an analogue computer simulation (Appendix) the dynamics of the luminescence wave shape were found to be compatible with a short sequence of first order processes acting on an initial brief transient.

scholarly journals On the nature of atmospherics—V

1937 ◽  
Vol 162 (909) ◽  
pp. 267-291 ◽  
Keyword(s):  
Time Constant ◽  
Ad Hoc ◽  
Input Circuit ◽  
Wave Form ◽  
Field Change ◽  
Adequate Sampling ◽  
Apparent Duration ◽  
Place Of Origin ◽  
Aerial Systems ◽  
Made In

Despite the defects and limitations of the methods described in the first three papers of this series (Watt and Appleton 1923; Appleton, Watt and Herd 1926), which were recognized from the first and towards whose elimination continued experimental work was directed, it was considered desirable to make a preliminary survey of the problem of the wave form of atmospherics without a waiting the results of this developmental work. Extensive series of observations were therefore made in the Red Sea and Indian Ocean, in Egypt, and in the Anglo-Egyptian Sudan, with "control" observations in south-eat England. In all of these series one or more of the present authors participated as observers. While no detailed discussion of the results is at present proposed, the general features of the survey are presented in Tables I-VI ( sec pages 289-291), in the form which was adopted for Table II of the second paper of this series. The authors' own criticisms of this early technique fell into two main groups: those arising from the impossibility, at the time of the early observations, of obtaining photographic records on any economically attainable basis of adequate sampling, and those arising from the lack of sufficient knowledge as to the place of origin of the disturbances studied. Some of the criticisms made by other workers, however, appeared to be based on misconception of matters discussed in the earlier papers. It is not now necessary to discuss these criticisms at length; one of the most important points at issue was very fully discussed at the Copenhagen meeting of the Union Radio Scientifique Internationale, and this discussion resulted in the complete acceptance of the argument of the papers, that the time constant of the input circuit, if sufficiently high, did not modify the apparent duration of the field change when the initial and final field values were sensibly the same. Ad hoc photographic testes by the authors, on large-aerial systems of the type used in the earlier work, in which the time constant was varied over wide limits had, in the interval, confirmed the view that sensible distortion of the recorded form only occurred when the time constant fell to the abnormally low value of about four times the duration of the field change to be delineated.

scholarly journals Off-Design Considerations through the Properties of Some Pressure-Ratio Line of Radial Inflow Turbines

2008 ◽  
Vol 2008 ◽  
pp. 1-8 ◽  
Author(s):  
N. Binder ◽  
X. Carbonneau ◽  
P. Chassaing
Keyword(s):  
Pressure Ratio ◽  
Design Procedure ◽  
Optimization Methods ◽  
Variable Geometry ◽  
Design Concepts ◽  
Recent Developments ◽  
Operating Constraints ◽  
Straight Lines ◽  
Radial Turbines ◽  
Two Machines

Radial turbines are commonly used in applications involving operation through severe off-design conditions. The emergence of variable-geometry systems leads to the distinction between two off-design concepts: operational and geometric off-designs. Both of these operating constraints should be integrated in the design procedure. Recent developments in prediction and optimization methods allowed such an integration, but involving complex algorithms is coupled with semiempiric loss models. This paper provides a basis to obtain simple information from an existing or predesigned machine, for both operational and geometric off-design conditions. An alternative turbine map is defined using loading and flow coefficients. A one-dimensional analysis shows that the constant pressure-ratio lines are straight lines whose slope is remarkably correlated with the pressure-ratio value and geometrical characteristics. This theoretical approach is validated against the experimentation of two machines, the linearity is observed in both cases. The direct influence of the stator configuration on the pressure-ratio lines confirms the applicability of this work to variable-geometry stages. A dimensionless cross-section of the stator is thus defined. However, the unexpected displacement of the intercept of the pressure-ratio lines limits the application field of this method. Nevertheless, a simple performance prediction analysis is proposed for blocked mass flow operation.

Theory of true-amplitude one-way wave equations and true-amplitude common-shot migration

Geophysics ◽  
2005 ◽  
Vol 70 (4) ◽  
pp. E1-E10 ◽  
Author(s):  
Yu Zhang ◽  
Guanquan Zhang ◽  
Norman Bleistein
Keyword(s):  
Wave Equation ◽  
Wave Equations ◽  
Forward Modeling ◽  
Inversion Method ◽  
Wave Form ◽  
Wave Operators ◽  
Full Wave ◽  
Migration Imaging ◽  
Standard Wave ◽  
And Migration

One-way wave operators are powerful tools for forward modeling and migration. Here, we describe a recently developed true-amplitude implementation of modified one-way operators and present some numerical examples. By “true-amplitude” one-way forward modeling we mean that the solutions are dynamically correct as well as kinematically correct. That is, ray theory applied to these equations yields the upward- and downward-traveling eikonal equations of the full wave equation, and the amplitude satisfies the transport equation of the full wave equation. The solutions of these equations are used in the standard wave-equation migration imaging condition. The boundary data for the downgoing wave is also modified from the one used in the classic theory because the latter data is not consistent with a point source for the full wave equation. When the full wave-form solutions are replaced by their ray-theoretic approximations, the imaging formula reduces to the common-shot Kirchhoff inversion formula. In this sense, the migration is true amplitude as well. On the other hand, this new method retains all of the fidelity features of wave equation migration. Computer output using numerically generated data confirms the accuracy of this inversion method. However, there are practical limitations. The observed data must be a solution of the wave equation. Therefore, the data must be collected from a single common-shot experiment. Multiexperiment data, such as common-offset data, cannot be used with this method as presently formulated.

Electronics and Biological Signal Processing

2011 ◽  
Author(s):  
Patrick Magee ◽  
Mark Tooley
Keyword(s):  
Resonant Frequency ◽  
Time Constant ◽  
Output Voltage ◽  
Voltage Divider ◽  
Band Pass Filter ◽  
Simple Circuit ◽  
Pass Filter ◽  
Square Wave ◽  
Band Pass

This chapter continues the discussion of electricity but looks at the effect of connecting components together and briefly looks at the operational amplifier and active circuits (circuits discussed in the previous chapter have been passive ones, which involve no electronic circuits). It will then describe how the circuits can be used to process biological signals. If a resistor, an inductor and a capacitor are joined as in Figure 5.1, the magnitude of the voltage across the resistor (Vout) will vary as the input frequency, Vin, changes, because of the properties of the capacitor and inductor. The resistive action of inductor and capacitor oppose each other, and at a certain resonant frequency (r in the figure), the total AC resistance (impedance) will be at a minimum. The graph of reactance against frequency demonstrates this, and shows the minimum reactance at the resonant frequency. As the LC and R are forming a voltage divider, the voltage across R will be maximum at this frequency. At other input frequencies, the output voltage will be low. This simple circuit forms the basics of the passive band-pass filter, where the filter passes, or lets through, a certain band of frequencies (around the resonant frequency in this circuit). Frequencies lower or higher than the band-pass will be attenuated. Normally operational amplifiers (discussed in the next section) or digital filters are more effective and are used to achieve the same effect. Resonance is important for the understanding of the behaviour of transducers and this is discussed in Chapter 12. If a square wave is applied to the resistor capacitor network as shown in Figure 5.2, the capacitor charges up on the rising edge of the input with a time constant equal to the product of the resistance (Ω) and the capacitance (F), RC, and the output voltage will be Vouput = Vinput (1 − e−t /RC ). When the square wave is in the off state, or zero volts, the voltage will fall exponentially with the same time constant. It can be seen from the diagram that, with the appropriate values of R and C, the output from the network is a filtered version of the input.

Eletroterapia em úlceras venosas: uma revisão integrativa

2019 ◽  
Vol 77 (15) ◽  
Author(s):  
Isabelle Andrade Silveira ◽  
Beatriz Guitton Renaud Baptista de Oliveira ◽  
Magali Rezende de Carvalho ◽  
Nelson Carvalho Andrade ◽  
Bruno Utzeri Peixoto
Keyword(s):  
Electrical Stimulation ◽  
Medical Center ◽  
Scientific Evidence ◽  
Wave Form ◽  
Electrical Stimulation Therapy ◽  
Level Of Evidence ◽  
Venous Ulcers ◽  
Grade Of Recommendation ◽  
Standard Wave ◽  
De Medicina

Objetivos: Descrever e analisar as evidências científicas encontradas na literatura sobre o uso da eletroterapiano reparo tecidual de úlceras venosas. Método: Revisão integrativa nas bases de dados: LILACS e MEDLINE viaPUBMED, utilizando os descritores: terapia por estimulação elétrica, úlceras venosas e cicatrização. Após a seleção,foi realizada leitura analítica, destacando: ano, título, local, autor, objetivos, método e resultados. A qualidade dosestudos foi avaliada de acordo com o Centro de Medicina Baseada em Evidências Oxford quanto ao nível de evidênciae grau de recomendação. Para análise, optou-se pela categorização temática. Resultados: Existem diferentes tiposde eletroterapias, porém não existe um padrão ouro de forma de onda e frequência de estimulação que seja omais efetivo; os estudos incluídos apresentaram resultados benéficos do uso da eletroterapia, bem como eficáciana redução do quadro álgico dos indivíduos com poucas semanas de intervenção. Conclusões: A eletroterapiaapresenta bons resultados na cicatrização de úlceras venosas, porém ainda existem lacunas importantes queprecisam ser preenchidas sobre seu uso, gerando uma demanda por estudos clínicos controlados para melhorverificar sua efetividade.Palavras-chave: Terapia por estimulação elétrica; Úlceras venosas; Cicatrização. ABSTRACTObjectives: To describe and analyze the scientific evidence in the literature on the use of electrotherapy fortissue repair venous ulcers. Method: Integrative review in databases: LILACS and MEDLINE via PubMed, using thekeywords: electrical stimulation therapy, venous ulcers and healing. After selecting analytical reading was held,highlighting: year, title, location, author, objectives, methods and results. Study quality was assessed accordingto the Medical Center Evidence-based Oxford as level of evidence and grade of recommendation. For analysisopted up the thematic categorization. Results: There are different types of electrotherapies, but there is nogold standard wave form and stimulation frequency that is the most effective; the included studies showedbeneficial results of the use of electrotherapy and efficacy in the pain reduction of individuals with few weeksof intervention. Conclusions: Electrotherapy gives good results in the healing of venous ulcers, but there are stillimportant gaps that need to be filled on its use, generating a demand for controlled clinical studies to furtherverify its effectiveness.Keywords: Electrical stimulation therapy; Venous ulcers; Healing.

Study of Shape Representation Using Internal Radiated-light Projection

2002 ◽  
Vol 14 (4) ◽  
pp. 357-365
Author(s):  
Takahiro Doi ◽  
◽  
Shigeo Hirose
Keyword(s):  
Shape Representation ◽  
Contour Analysis ◽  
Shape Information ◽  
Local Shape ◽  
3D Objects ◽  
Recent Developments ◽  
Real Objects ◽  
Object Shapes ◽  
Straight Lines ◽  
3D Shapes

Recent developments in 3D sensors have raised the possibility of using them in an increasing number of engineering applications. However, since most 3D sensors, such as the laser range finder, are based on the use of light, which moves in straight lines, the measurement area is limited to the front of an object, making the back an ""invisible"" surface. To calculate such unmeasurable areas, a system that memorizes shapes often encountered in objects and superimposes them on the scene is required. To realize such a type of system, an appropriate 3D shape representation is needed. This representation should 1) be able to handle and compare partial and complete sets of data of object shapes, and 2) operate quickly enough to be applicable to real-time tasks. We developed a novel shape representation framework called ""Internal Radiated-light Projection (IRP)"" to represent and compare 3D objects. This representation projects local shape information of an object on a sphere by imaginary rays from the ""kernel"" of the object. To describe local shape information and arrange shapes properly, we propose Harmonic Contour Analysis (HCA) and the Shape Matrix. These concepts are characterized by 1) simplicity; 2) the use of local shapes and their adjacent information; and, by using the Shape Matrix, 3) the consideration of the effect of gravity and stable poses for objects. In IRP representation, we can categorize objects in known classes and calculate their positions and attitudes. This paper explains the basic concept behind IRP, which is a way of representing local 3D shapes by HCA and categorizing them using the Shape Matrix. We then present experiments in object recognition for both virtual and real objects to demonstrate its efficiency and feasibility.

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