A recalculation of the age of the solar system

1969 ◽  
Vol 6 (4) ◽  
pp. 719-735 ◽  
Author(s):  
G. L. Cumming
Keyword(s):  
Solar System ◽  
Large Body ◽  
Radioactive Decay ◽  
New Method ◽  
Experimental Techniques ◽  
Correlated Errors ◽  
Straight Line

A new method of fitting a straight line to experimental points with correlated errors has been used to recalculate the age of the solar system using several different radioactive decay systems. It is shown that the possibility of correlated errors should not be neglected in evaluating the errors in the slope of a straight line fitted to experimental points. It is also shown that in spite of the large body of data now available, the usually accepted value of about 4550 ± 50 m.y. is the best that can be justified by the data. Most of the uncertainty seems to be experimental in origin and could probably be substantially reduced by careful application of presently available experimental techniques.

scholarly journals A New Method for the Extraction of Diode Parameters Using a Single Exponential Model

2000 ◽  
Vol 22 (3) ◽  
pp. 157-163 ◽  
Author(s):  
S. Dib ◽  
M. De La Bardonnie ◽  
A. Khoury ◽  
F. Pelanchon ◽  
P. Mialhe
Keyword(s):  
Least Squares Method ◽  
Exponential Model ◽  
New Method ◽  
Ordinate Axis ◽  
Straight Line ◽  
Current Voltage ◽  
Method Approach ◽  
Single Exponential

A new method for extracting junction parameters of the single diode model is presented. A least squares method approach considers the deviation ∆V=f(I) between the experimental current-voltage (I-V) characteristic and a theoretical arbitrary characteristic. A specific case- the ∆V graph reducing to a straight line–is identified and the knowledge of the slope and of the intercept with the ordinate axis leads to the determination of the junction parameters. The method is applied to the characterization of the emitter-base junction of transistors and the results are discussed.

scholarly journals A New Method for the Evaluation of Well Rehabilitation from the Early Portion of a Pumping Test

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 744
Author(s):  
Daniel Kahuda ◽  
Pavel Pech
Keyword(s):  
Skin Effect ◽  
Pumping Test ◽  
Real Space ◽  
New Method ◽  
Maximum Slope ◽  
Skin Factor ◽  
Wellbore Storage ◽  
Straight Line ◽  
Early Portion ◽  
Well Rehabilitation

This study analyzes the unsteady groundwater flow to a real well (with wellbore storage and the skin effect) that fully penetrates the confined aquifer. The well is located within an infinite system, so the effect of boundaries is not considered. The Laplace-domain solution for a partial differential equation is used to describe the unsteady radial flow to a well. The real space solution is obtained by means of the numerical inversion of the Laplace transform using the Stehfest algorithm 368. When wellbore storage and the skin effect dominate pumping test data and testing is conducted for long enough, two semilogarithmic straight lines are normally obtained. The first straight line can be identified readily as the line of the maximum slope. The correlation of the dimensionless drawdown for the intersection time of this first straight line, with the log time axis as a function of the dimensionless wellbore storage and the skin factor, is shown. This paper presents a new method for evaluating the skin factor from the early portion of a pumping test. This method can be used to evaluate the skin factor when the well-known Cooper–Jacob semilogarithmic method cannot be used due to the second straight line not being achieved in the semilogarithmic graph drawdown vs. the log time. A field example is presented to evaluate the well rehabilitation in Veselí nad Lužnicí by means of the new correlation.

scholarly journals Topological patterns in two-dimensional gel electrophoresis of DNA knots

2015 ◽  
Vol 112 (40) ◽  
pp. E5471-E5477 ◽  
Author(s):  
Davide Michieletto ◽  
Davide Marenduzzo ◽  
Enzo Orlandini
Keyword(s):  
Physical Properties ◽  
Experimental Work ◽  
Gel Electrophoresis ◽  
Large Body ◽  
2D Electrophoresis ◽  
Topological Complexity ◽  
Two Dimensional ◽  
Two Dimensional Gel Electrophoresis ◽  
Theoretical Understanding ◽  
Straight Line

Gel electrophoresis is a powerful experimental method to probe the topology of DNA and other biopolymers. Although there is a large body of experimental work that allows us to accurately separate different topoisomers of a molecule, a full theoretical understanding of these experiments has not yet been achieved. Here we show that the mobility of DNA knots depends crucially and subtly on the physical properties of the gel and, in particular, on the presence of dangling ends. The topological interactions between these and DNA molecules can be described in terms of an “entanglement number” and yield a nonmonotonic mobility at moderate fields. Consequently, in 2D electrophoresis, gel bands display a characteristic arc pattern; this turns into a straight line when the density of dangling ends vanishes. We also provide a novel framework to accurately predict the shape of such arcs as a function of molecule length and topological complexity, which may be used to inform future experiments.

An Investigation on Multi-Nozzle near Field Electrospinning: Experimentation and Simulation

2016 ◽  
Vol 679 ◽  
pp. 63-66 ◽  
Author(s):  
Shen Neng Huang ◽  
Xin Du Chen ◽  
Zhi Feng Wang ◽  
Jun Zeng ◽  
Fei Yu Fang ◽  
...  
Keyword(s):  
Electric Field ◽  
Near Field ◽  
Industrial Applications ◽  
Experimental Results ◽  
New Method ◽  
Machining Efficiency ◽  
Great Tendency ◽  
Field Density ◽  
Straight Line

There are massive reports about near-field electrospinning (NFES) in the literature and the NFES has great tendency for scientific and industrial applications. It is important to improve the machining efficiency of electrospinning. Through the study of the multi-nozzle near-field electrospinning, a new method by adjusting the electrode-to-collector distance (E-C-D) is presented in this paper to make sure the jets with a straight line. The method is divided into two steps: (1) to adjust the E-C-D larger to get the jet at each nozzle, (2) to make the E-C-D smaller enough to get straight jets. Moreover, this paper simulates the electric field density which helps to provide a further understanding on the process of NFES. The experimental results contribute to making a better control on the jets in NFES.

An Improved PID Control for Wheeled Line-Tracking Robot

2013 ◽  
Vol 401-403 ◽  
pp. 1661-1665
Author(s):  
Jun Chen ◽  
Jun Qiang
Keyword(s):  
Intelligent Control ◽  
Pid Control ◽  
Tracking Algorithm ◽  
New Method ◽  
Experimental Result ◽  
Channel Bend ◽  
Straight Line ◽  
Line Tracking ◽  
Design Requirements

This paper takes the wheeled line-tracking robot as the investigative object and the realization of intelligent control as the target, bases on SCM STC12C5A60S2, make the design of line-tracking robots soft hardware, and the line-tracking algorithm emphasis, presents a new method in PID control, and combining straight-line acceleration and channel bend modification, The experimental result shows that this line-tracking robot meets the design requirements with rapid moving and stability.

Calibration of wheeled mobile robots with differential drive mechanisms: an experimental approach

Robotica ◽  
2012 ◽  
Vol 30 (6) ◽  
pp. 1029-1039 ◽  
Author(s):  
Y. Maddahi ◽  
N. Sepehri ◽  
A. Maddahi ◽  
M. Abdolmohammadi
Keyword(s):  
Mobile Robot ◽  
Mobile Robots ◽  
Experimental Approach ◽  
Systematic Errors ◽  
New Method ◽  
University Of Michigan ◽  
Wheeled Mobile Robots ◽  
Differential Drive ◽  
Error Corrections ◽  
Straight Line

SUMMARYExact knowledge of the position and proper calibration of robots that move by wheels form an important foundation in mobile robot applications. In this context, a variety of sensory systems and techniques have been developed for accurate positioning of differential drive mobile robots. This paper, first, provides a brief overview of mobile robots positioning techniques and then, presents a new benchmark method capable of calibrating mobile robots with differential drive mechanisms to correct systematic errors. The proposed method is compared with the commonly used University of Michigan Benchmark (UMBmark) odometry method. Two sets of comparisons are conducted on six prototyped robots with differential drives. The first set of tests establishes the workability and accuracy that can be achieved with the new method and compares them with the ones obtained from the UMBmark technique. The second experiment compares the performance of a mobile robot, calibrated with either the UMBmark or the new method, for an unseen path. It is demonstrated that the proposed method of calibration is simple to implement, and leads to accuracy comparable to the UMBmark method. Specifically, while the error corrections in both methods are within ±5% of each other, the proposed method requires single straight line motion for calibration, which is believed to be simpler and less timely to implement than the square path motion required by the UMBmark technique. The method should therefore be considered seriously as a new tool when calibrating differential drive mobile robots.

scholarly journals Observational constraints on the likelihood of 26Al in planet-forming environments

2020 ◽  
Vol 644 ◽  
pp. L1
Author(s):  
Megan Reiter
Keyword(s):  
Solar System ◽  
Planet Formation ◽  
Radioactive Decay ◽  
High Mass ◽  
Mass Star ◽  
Early Solar System ◽  
Star Forming ◽  
Star Forming Regions ◽  
The Galaxy ◽  
Order Of Magnitude

Recent work suggests that 26Al may determine the water budget in terrestrial exoplanets as its radioactive decay dehydrates planetesimals leading to rockier compositions. Here I consider the observed distribution of 26Al in the Galaxy and typical star-forming environments to estimate the likelihood of 26Al enrichment during planet formation. I do not assume Solar-System-specific constraints as I am interested in enrichment for exoplanets generally. Observations indicate that high-mass stars dominate the production of 26Al with nearly equal contributions from their winds and supernovae. Observed 26Al abundances are comparable to those in the early Solar System in the high-mass star-forming regions where most stars (and thereby most planets) form. These high abundances appear to be maintained for a few million years, which is much longer than the 0.7 Myr half-life. Observed bulk 26Al velocities are an order of magnitude slower than expected from winds and supernovae. These observations are at odds with typical model assumptions that 26Al is provided instantaneously by high velocity mass loss from supernovae and winds. The regular replenishment of 26Al, especially when coupled with the small age differences that are common in high-mass star-forming complexes, may significantly increase the number of star- and planet-forming systems exposed to 26Al. Exposure does not imply enrichment, but the order of magnitude slower velocity of 26Al may alter the fraction that is incorporated into planet-forming material. Together, this suggests that the conditions for rocky planet formation are not rare, nor are they ubiquitous, as small regions such as Taurus, that lack high-mass stars to produce 26Al may be less likely to form rocky planets. I conclude with suggested directions for future studies.

scholarly journals A new method for calculating individual subitizing ranges

2018 ◽  
Vol 4 (2) ◽  
pp. 429-447 ◽  
Author(s):  
Tali Leibovich-Raveh ◽  
Daniel Jacob Lewis ◽  
Saja Al-Rubaiey Kadhim ◽  
Daniel Ansari
Keyword(s):  
Working Memory ◽  
Individual Differences ◽  
Empirical Studies ◽  
Large Body ◽  
New Method ◽  
Mathematical Abilities ◽  
Matlab Code ◽  
Easy Calculation ◽  
Subitizing Range ◽  
Human Adults

A large body of research has shown that human adults are fast and accurate at enumerating arrays of ~1-4 items. This phenomenon has been called subitizing. Above this range, enumeration is slower and less accurate. The subitizing range has been related to individual differences in variables such as mathematical abilities, working memory, etc. The two most common methods for calculating subitizing range today – bilinear fit and sigmoid fit – have their strengths and weaknesses. By combining these two methods, we overcome their biggest limitations and come up with a novel way for calculating Individual Subitizing Range (ISR). This paper introduces this new method as well as empirical studies designed to test the new method. We replicated classic effects from the literature and obtain a high correlation with the sigmoid fit method. This paper includes a Matlab code for easy calculation of ISR as well as a ready-to-use experimental file for testing ISR. We hope that these tools would be of use to researchers studying individual differences in the subitizing range.

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