Study on Wear of Grinding Wheels: 1—Bond Fracture in Grinding Wheels

1963 ◽  
Vol 85 (1) ◽  
pp. 39-42 ◽  
Author(s):  
Hiroyuki Yoshikawa ◽  
Toshio Sata
Keyword(s):  
Brittle Fracture ◽  
Wear Rate ◽  
Exponential Function ◽  
Grinding Force ◽  
Theoretical Interpretation ◽  
Grinding Wheels ◽  
Double Exponential ◽  
Double Exponential Function ◽  
Single Exponential Function ◽  
Single Exponential

Fracturing of bond bridges in grinding wheels is explained from the standpoint of brittle-fracture. It is shown that the wear rate of grinding wheels can be expressed as the single exponential function of the grinding speed and as the double exponential function of the grinding force. Experimental results are shown to confirm the theoretical interpretation.

Myocardial blood flow determined with krypton 85 in unanesthetized dogs

1962 ◽  
Vol 203 (1) ◽  
pp. 122-124 ◽  
Author(s):  
J. A. Herd ◽  
M. Hollenberg ◽  
G. D. Thorburn ◽  
H. H. Kopald ◽  
A. C. Barger
Keyword(s):  
Blood Flow ◽  
Coronary Artery ◽  
Myocardial Blood Flow ◽  
Exponential Function ◽  
Scintillation Detector ◽  
Left Ventricular ◽  
Blood Flows ◽  
Single Exponential Function ◽  
Single Exponential ◽  
Rapid Measurements

Serial, rapid measurements of left ventricular myocardial blood flow in trained, unanesthetized dogs have been made by injecting krypton 85 through chronically implanted coronary artery catheters and counting with an external scintillation detector. Precordial radioactivity declined as a single exponential function during the first 2 min after injection, suggesting a single rate of myocardial blood flow. Simultaneous estimations with Kr85 and blood flowmeters in acute experiments established the accuracy and reproducibility of the technique. Myocardial blood flows between 40 and 55 ml/100 g/min were observed repeatedly in three well-trained, unanesthetized dogs in the basal state.

TEMPORAL PROPERTIES OF PHOTOREFRACTIVE MATERIALS

1996 ◽  
Vol 05 (01) ◽  
pp. 9-24 ◽  
Author(s):  
D. STATMAN ◽  
G.C. GILBREATH
Keyword(s):  
Exponential Function ◽  
Modulation Depth ◽  
Rate Equations ◽  
Temporal Properties ◽  
High Modulation ◽  
Beam Coupling ◽  
Double Exponential ◽  
Photorefractive Materials ◽  
Double Exponential Function

Photorefractive two-beam coupling is examined experimentally for the case of high modulation depth. It is seen that the dynamics of signal growth and decay are best described by a double exponential function. The properties of this function with respect to interaction angle and modulation depth are studied. It is suggested that the equations governing photorefractive dynamics may be reduced to a pair of coupled bilinear rate equations which adequately describe photorefractive dynamics for high modulation depth.

The Hardness Changing Regularity of Quenched-Steel in Tempering Process and Its Double-Exponential Model

2010 ◽  
Vol 146-147 ◽  
pp. 1578-1582
Author(s):  
Cong Sheng Guo ◽  
Shu Ming Long ◽  
Hai Wa Bo ◽  
Hong Bin Tan
Keyword(s):  
Phase Transformation ◽  
Exponential Function ◽  
Optimization Design ◽  
Hardness Test ◽  
Exponential Model ◽  
Physical Metallurgy ◽  
Double Exponential ◽  
Quenched Steel ◽  
Double Exponential Function ◽  
Tempering Process

The transformation of tempering for quenched steel corresponded to complicated process of phase transformation, and mechanical properties of quenched-and-tempered steel were related to the phase transformation. In practice, hardness test was adopted to judge whether the properties of tempered-parts qualified because of its facility. Numerous researches indicated that, there existed correlativity expressed by different function forms between tempering hardness of quenched-steel and its tempering parameters. However, considering physical metallurgy of tempering process, the adoption of double-exponential function would help to describe regularity of hardness changing more exactly for quenched-steel during tempering process. Additionally, results of hardness tests for isothermal tempering and molding/simulation researches have shown that, the model of double-exponential function, which can reflect decline law of tempering hardness for quenched-steel, would provide basis for optimization design of tempering parameters, performance prediction of tempered-parts, and energy-saving heat-treatment on tempering process.

Whole-cell and single-channel recordings of GABA-gated currents in cultured chick cerebral neurons

1988 ◽  
Vol 59 (2) ◽  
pp. 495-513 ◽  
Author(s):  
D. S. Weiss ◽  
E. M. Barnes ◽  
J. J. Hablitz
Keyword(s):  
Membrane Potential ◽  
Time Constant ◽  
Exponential Function ◽  
Single Channel ◽  
Synaptic Currents ◽  
Whole Cell ◽  
Cerebral Neurons ◽  
Single Exponential Function ◽  
Single Exponential ◽  
Conductance State

1. gamma-Aminobutyric acid (GABA) (10-500 microM) was applied to cultured chick cerebral neurons by pressure ejection, and the resulting currents (IGABA) were recorded using standard whole-cell voltage-clamp techniques. Plots of the peak IGABA as a function of membrane potential were nonlinear with an outwardly rectifying appearance. 2. IGABA decayed during a prolonged application of GABA. This decay was associated with a decline in the conductance of the cell, suggesting that the decline in IGABA was principally due to receptor desensitization. 3. After 5-7 days in culture, whole-cell recordings revealed the presence of spontaneous synaptic currents. These currents were presumed to be GABA-gated inhibitory postsynaptic currents (IPSCs) because they reversed at the Cl- equilibrium potential (ECl-), were blocked by picrotoxin (25 microM), and were prolonged by pentobarbital (50 microM). 4. Synaptic currents were analyzed by fitting exponential functions to their decay. In normal recording saline, 68% of the decays analyzed could be adequately described by a single exponential function. Two exponentials were necessary to describe the decay of the other 32%. The time constant of the decay (for those adequately fitted by a single exponential) increased with depolarization, from an average value of 15 ms at -80 mV to 60 ms at +40 mV. 5. A relationship was noted between IPSC amplitude and decay time constant; IPSCs with larger peak amplitudes had a slower decay. One possible explanation considered for this finding was that transmitter persists in the synaptic cleft and rebinds to the receptors, thus prolonging the decay of the IPSC. 6. Consistent with the above hypothesis was the observation that the decays of miniature IPCSs (examined under conditions of reduced transmitter release) were faster, showed less variability, and were all adequately described by a single exponential function. Furthermore, the decay times were independent of the membrane potential, suggesting that the kinetic parameters of the GABA channel which shape the decay of these miniature IPSCs are independent of voltage. 7. Single-channel activity underlying whole-cell GABA responses could be recorded in isolated outside-out and inside-out patches of membrane. In isotonic choline chloride, single-channel amplitudes were linearly related to voltage and reversed at -1.8 +/- 11.0 mV (n = 12). Under these conditions, the channel had a main conductance state of 20.8 +/- 3.4 pS (n = 12). Transitions were observed from this main conductance state to other conductance states, e.g., two subconductance states of 6 and 12 pS and one supraconductance state of 30 pS.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals El proceso de difusión para variedades mejoradas de Phaseolus vulgaris L. en Guatemala.

2016 ◽  
Vol 5 ◽  
pp. 08
Author(s):  
Marco Baltensweiler
Keyword(s):  
Diffusion Process ◽  
Exponential Function ◽  
Good Description ◽  
Marginal Rate ◽  
Marginal Rate Of Substitution ◽  
Lack Of Information ◽  
Double Exponential ◽  
Acquisition Costs ◽  
Relationship Of ◽  
Double Exponential Function

A double exponential function provides a good description of this diffusion process. This function was derived from the data concerning the diffusion process of the two improved varieties ICT A-Ostua and ICT ASan Martin V.B. in Guatemala in the years 1990-1992. The two relevant parameters may be interpreted in the following way: Parameter a1 reflects the marginal rate of substitution between the yields obtained from both, the improved and the farmer' s bean varieties. Parameter a2 considers the relationship of the acquisition costs among the two varieties, which are based on the seed price plus the transaction's costs. This concept allows to discern the difficulties faced by the farmers, such as the lack of information of where and when to acquire the improved seed, the delivery costs and so on. Unfortunately, this function no~ only tends to over-estimate the number of farmers who buy the improved seed during the year of maximum demand but al so the time span of this maximum demando A third degree polynome would be more appropiated, but its inter-dependent parameters are more difficult to interptet, in contrast to the easy interpretation of the double exponential function.

scholarly journals A harmonic analysis of exponential decay

2020 ◽  
Author(s):  
David Lawunmi ◽  
Soodamani Ramalingam
Keyword(s):  
Harmonic Analysis ◽  
Exponential Function ◽  
Exponential Decay ◽  
Harmonic Functions ◽  
Exponential Functions ◽  
Single Exponential Function ◽  
Single Exponential

We analyse the decay of a single exponential function and develop an algorithm to determine the exponent and the constant, C, (C exp(-kt)) associated with this function . In essence this approach involves `transforming' exponential functions into harmonic functions. This manoeuvre allows techniques that are used to analyse harmonic functions to be used to characterise decaying exponential functions.

Principles and Utilization of the Electron Beam Damage of Synthetic Polymers

1990 ◽  
Vol 48 (2) ◽  
pp. 410-411
Author(s):  
D. Vesely
Keyword(s):  
Exponential Function ◽  
Structural Investigations ◽  
Rapid Decomposition ◽  
Damage Rate ◽  
Double Exponential ◽  
Loss Of Mass ◽  
Polymeric Samples ◽  
Double Exponential Function ◽  
Beam Damage ◽  
Initial Intensity

The rapid decomposition of polymeric samples is a major problem in structural investigations of these materials, as the crystallographic information and mass/thickness contrast can be quickly lost. The X-ray elemental analysis can also be affected by loss of elements and often extrapolation to zero exposure is necessary. It is thus of great interest to know how quickly this decomposition occurs for a given polymer.The beam damage rate can be measured by loss of crystallinity, loss of mass or loss of elements. The measured decay curves can be approximated by a double exponential function for which only three constants are needed. This describes the behaviour of most polymers very well, however an accurate experimental evaluation of these constants is not easy. The most important and difficult parameters to measure are the initial intensity, exposure and size of the irradiated area. It is not clear why the double exponential function is suitable, if it is a chemical law or if it fits purely by coincidence.

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