Chronology (in Logarithmic Scale) of Main Eras Mentioned, 20,000–400 B.C.

2021 ◽  
pp. xxx-xxx
Keyword(s):  
Author(s):  
D.P. Malta ◽  
M.L. Timmons

Measurement of the minority carrier diffusion length (L) can be performed by measurement of the rate of decay of excess minority carriers with the distance (x) of an electron beam excitation source from a p-n junction or Schottky barrier junction perpendicular to the surface in an SEM. In an ideal case, the decay is exponential according to the equation, I = Ioexp(−x/L), where I is the current measured at x and Io is the maximum current measured at x=0. L can be obtained from the slope of the straight line when plotted on a semi-logarithmic scale. In reality, carriers recombine not only in the bulk but at the surface as well. The result is a non-exponential decay or a sublinear semi-logarithmic plot. The effective diffusion length (Leff) measured is shorter than the actual value. Some improvement in accuracy can be obtained by increasing the beam-energy, thereby increasing the penetration depth and reducing the percentage of carriers reaching the surface. For materials known to have a high surface recombination velocity s (cm/sec) such as GaAs and its alloys, increasing the beam energy is insufficient. Furthermore, one may find an upper limit on beam energy as the diameter of the signal generation volume approaches the device dimensions.


1993 ◽  
Vol 27 (3-4) ◽  
pp. 1-13 ◽  
Author(s):  
Arie H. Havelaar ◽  
Siem H. Heisterkamp ◽  
Janneke A. Hoekstra ◽  
Kirsten A. Mooijman

The general concept of measurement errors is applied to quantitative bacteriological counts on membrane filters or agar plates. The systematic errors of these methods are related to the growth characteristics of the medium (recovery of target organisms and inhibition of non-target organisms) and to its differential characteristics (sensitivity and specificity). Factors that influence the precision of microbiological counts are the variation between replicates, within samples, between operators and between laboratories. It is also affected by the linearity of the method, the verification rate and, where applicable, the number of colonies subcultured for verification. Repeatability (r) and reproducibility (R) values can be calculated on the logarithmic scale.


Author(s):  
Hellen S. Santos ◽  
Karine L. Buarque da Silva ◽  
Ariel E. Zanini ◽  
Danilo S. Coelho ◽  
Marcelo Embiruçu ◽  
...  

Background: Brazilian bentonites have a low sodium concentration in their interlayer structure. This is a problem with most of the industrial applications that demand the characteristics of sodium bentonites. Objective: As a solution for this limitation, sodium carbonate is added to in natura clays, promoting ion exchange between other interlayer cations with sodium. Methods: A process was used based on the principle of Stokes’ Law (BR Patent 10 2013 016298). For this, we used four glass columns in series, in which a high water flow was considered to obtain purified clays. It was proposed as a simple, fast and economical method for sodium determination that was developed and applied in bentonites by flame photometry. The equipment calibration was performed with a NaCl standard solution in concentrations between 80 and 110 ppm. The bentonites in the suspension were separated by means of centrifugation, being thus analyzed by a flame photometer. Results: The samples were prepared according to the manufacturer’s specifications to contain detectable amounts of sodium by means of flame photometry. A resulting linear relationship between the average value readings versus sodium standard content solution (both in ppm) was obtained by the logarithmic scale, as expected. Conclusion: The procedure allowed to define a method that could be used in the sodification control process, thus making it possible to differentiate the sodium cation content in terms of the value of cation exchange capacity (CEC) from bentonite. X-ray analysis of in natura and the sodified clays showed nanostructural differences related to interlayer distance.


Mathematics ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 303
Author(s):  
Nikolai Krivulin

We consider a decision-making problem to evaluate absolute ratings of alternatives from the results of their pairwise comparisons according to two criteria, subject to constraints on the ratings. We formulate the problem as a bi-objective optimization problem of constrained matrix approximation in the Chebyshev sense in logarithmic scale. The problem is to approximate the pairwise comparison matrices for each criterion simultaneously by a common consistent matrix of unit rank, which determines the vector of ratings. We represent and solve the optimization problem in the framework of tropical (idempotent) algebra, which deals with the theory and applications of idempotent semirings and semifields. The solution involves the introduction of two parameters that represent the minimum values of approximation error for each matrix and thereby describe the Pareto frontier for the bi-objective problem. The optimization problem then reduces to a parametrized vector inequality. The necessary and sufficient conditions for solutions of the inequality serve to derive the Pareto frontier for the problem. All solutions of the inequality, which correspond to the Pareto frontier, are taken as a complete Pareto-optimal solution to the problem. We apply these results to the decision problem of interest and present illustrative examples.


Biosensors ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 85
Author(s):  
Wassa Waiwinya ◽  
Thitirat Putnin ◽  
Dechnarong Pimalai ◽  
Wireeya Chawjiraphan ◽  
Nuankanya Sathirapongsasuti ◽  
...  

An immobilization-free electrochemical sensor coupled with a graphene oxide (GO)-based aptasensor was developed for glycated human serum albumin (GHSA) detection. The concentration of GHSA was monitored by measuring the electrochemical response of free GO and aptamer-bound GO in the presence of glycated albumin; their currents served as the analytical signals. The electrochemical aptasensor exhibited good performance with a base-10 logarithmic scale. The calibration curve was achieved in the range of 0.01–50 µg/mL. The limit of detection (LOD) was 8.70 ng/mL. The developed method was considered a one-drop measurement process because a fabrication step and the probe-immobilization process were not required. This simple sensor offers a cost-effective, rapid, and sensitive detection method, and could be an alternative approach for determination of GHSA levels.


2021 ◽  
Vol 5 (2) ◽  
pp. 36
Author(s):  
Jun-Sheng Duan ◽  
Di-Chen Hu ◽  
Yang-Quan Chen

We considered relaxation, creep, dissipation, and hysteresis resulting from a six-parameter fractional constitutive model and its particular cases. The storage modulus, loss modulus, and loss factor, as well as their characteristics based on the thermodynamic requirements, were investigated. It was proved that for the fractional Maxwell model, the storage modulus increases monotonically, while the loss modulus has symmetrical peaks for its curve against the logarithmic scale log(ω), and for the fractional Zener model, the storage modulus monotonically increases while the loss modulus and the loss factor have symmetrical peaks for their curves against the logarithmic scale log(ω). The peak values and corresponding stationary points were analytically given. The relaxation modulus and the creep compliance for the six-parameter fractional constitutive model were given in terms of the Mittag–Leffler functions. Finally, the stress–strain hysteresis loops were simulated by making use of the derived creep compliance for the fractional Zener model. These results show that the fractional constitutive models could characterize the relaxation, creep, dissipation, and hysteresis phenomena of viscoelastic bodies, and fractional orders α and β could be used to model real-world physical properties well.


F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 1222 ◽  
Author(s):  
Gabriele Scheler

In this paper, we present data for the lognormal distributions of spike rates, synaptic weights and intrinsic excitability (gain) for neurons in various brain areas, such as auditory or visual cortex, hippocampus, cerebellum, striatum, midbrain nuclei. We find a remarkable consistency of heavy-tailed, specifically lognormal, distributions for rates, weights and gains in all brain areas examined. The difference between strongly recurrent and feed-forward connectivity (cortex vs. striatum and cerebellum), neurotransmitter (GABA (striatum) or glutamate (cortex)) or the level of activation (low in cortex, high in Purkinje cells and midbrain nuclei) turns out to be irrelevant for this feature. Logarithmic scale distribution of weights and gains appears to be a general, functional property in all cases analyzed. We then created a generic neural model to investigate adaptive learning rules that create and maintain lognormal distributions. We conclusively demonstrate that not only weights, but also intrinsic gains, need to have strong Hebbian learning in order to produce and maintain the experimentally attested distributions. This provides a solution to the long-standing question about the type of plasticity exhibited by intrinsic excitability.


1999 ◽  
Vol 5 (2) ◽  
pp. 108-115
Author(s):  
Antanas Alikonis

Disturbance of soil structure influences its density, strength and deformation properties. Among other cases soil structure could be disturbed by compacting it. It is possible to increase deformation properties of sand or gravel by compacting them. However, for clay soils deformation properties may increase if they are compacted. Differences of settlements of a building depends on the different deformation properties of the artificially placed and compacted soils beneath the foundations. Different values of stiffness modulus are used for the structural design of the buildings which are constructed on the soils with different compressibility. Coefficient of changeability of soil compression (1) was used. It may be calculated as a ratio of maximum and minimum values of deformation modulus, or according to the maximum and minimum values of coefficient of relative compressibility (3). Coefficient of the relative compressibility of soil can be calculated depending on the maximum and minimum values of tip resistence from CPT test (5). According to the coefficient of the relative compressibility we could estimate whether the soil is uniform, nonuniform or extremely non-uniform. It is important for the design of civil engineering structures. Mechanical properties of soils may be back-calculated using theoretical values of settlements and loads. Most frequently within the building layout area soils are natural and artificially compacted. For a compacted soil it is possible to draw compression curve in semi-logarithmic scale using compression curve of the same natural soil and the void ratio of the artificially placed and compacted soil. Thus we can determine compressibility of the soil with disturbed or undisturbed structure. Using parameters of soil compressibility, we can determine the coefficient of the relative compressibility, maximum and minimum values of settlement and modulus of stiffness.


Author(s):  
C. Matthew ◽  
A. Hernandez-Garay ◽  
J. Hodgson

Interpretation of tiller or shoot density data requires resolution of two independent, confounding effects, namely size/density compensation and what is here called the "leaf area effect". Size/density compensation implies that at higher herbage mass, individual tillers or shoots are larger, but the population density is correspondingly decreased. The leaf area effect represents difference in sward leaf area for two tiller populations. Such leaf area differences may be environmentally or genetically determined, but must of necessity be expressed through change in tiller size and/or tiller density as "yield components" of leaf area. The theoretical basis for distinguishing between size/density compensation and the leaf area effect is to consider tiller or shoot density and herbage yield, respectively, as X,Y co-ordinates in a size/density plot. When such a plot is drawn on a logarithmic scale, points along a line of -l/2 slope show size/ density compensation with respect to each other. Movement of points to the right or left of the size/ density compensation line is evidence of a leaf area effect. It is shown that when the size/density effects are removed from a data set in this way, rankings of experimental treatments for the leaf area effect can often be reversed compared with the ranking of uncorrected tiller density. Tiller density data corrected for size/density compen-. sation in this way appear to be a useful indicator of sward productivity. Keywords: sizeldensity compensation, sward productivity, tiller density


2019 ◽  
Author(s):  
Lise Hobeika ◽  
Marine Taffou ◽  
Thibaut Carpentier ◽  
Olivier Warusfel ◽  
Isabelle Viaud-Delmon

AbstractHighlightsLogarithmically distributed auditory distances provides an apt granularity of PPSMeasuring expectation helps to interpret behavioral impact of audiotactile integrationTactile RTs follows a logarithmic decrease due to audiotactile integrationPeripersonal space is better characterized and quantified with this refinementBackgroundHumans perceive near space and far space differently. Peripersonal space, i.e. the space directly surrounding the body, is often studied using paradigms based on auditory-tactile integration. In these paradigms, reaction time to a tactile stimulus is measured in the presence of a concurrent auditory looming stimulus.New MethodWe propose here to refine the experimental procedure considering sound propagation properties in order to improve granularity and relevance of auditory-tactile integration measures. We used a logarithmic distribution of distances for this purpose. We also want to disentangle behavioral contributions of the targeted audiotactile integration mechanisms from expectancy effects. To this aim, we added to the protocol a baseline with a fixed sound distance.ResultsExpectation contributed significantly to overall behavioral responses. Subtracting it isolated the audiotactile effect due to the stimulus proximity. This revealed that audiotactile integration effects have to be tested on a logarithmic scale of distances, and that they follow a linear variation on this scale.Comparison with Existing Method(s)The granularity of the current method is more relevant, providing higher spatial resolution in the vicinity of the body. Furthermore, most of the existing methods propose a sigmoid fitting, which rests on the intuitive framework that PPS is an in-or-out zone. Our results suggest that behavioral effects follow a logarithmic decrease, thus a response graduated in space.ConclusionsThe proposed protocol design and method of analysis contribute to refine the experimental investigation of the factors influencing and modifying multisensory integration phenomena in the space surrounding the body.


Sign in / Sign up

Export Citation Format

Share Document