Some geometrical properties of fission-track-surface intersections in apatite

2020 ◽  
Vol 105 (9) ◽  
pp. 1355-1364
Author(s):  
Raymond Jonckheere ◽  
Carolin Aslanian ◽  
Bastian Wauschkuhn ◽  
Lothar Ratschbacher
Keyword(s):  
Kinetic Parameter ◽  
Fission Track ◽  
Current Model ◽  
Frequency Distributions ◽  
Geometrical Properties ◽  
Surface Etching ◽  
Track Etching ◽  
Etched Surface ◽  
Track Surface ◽  
Surface Intersections

Abstract Parallel fission-track-surface intersections identify the grains in an etched apatite mount that have been polished parallel to their prism faces and mark the orientations of their c-axes. Their lengths (Dpar) are a practical kinetic parameter that is indicative of the track annealing rate of apatite. Little is known, however, about their geometrical properties in non-prism faces. We present a model calculation of the frequency distributions of the orientations, lengths, and widths of track-surface intersections in non-prism faces. The current model does not include the effects of surface etching or measurement imprecision. However, as far as it goes, it is consistent with measurements in apatite surfaces up to 30° to the c-axis. Regardless of the model, we submit that the statistical properties of the fission-track-surface intersections have practical uses. The distribution of their orientations is characteristic of the orientation of the etched surface relative to the c-axis. The distribution of their lengths presents a possible tool for investigating track etching, in particular for evaluating the tracks added and lost through surface etching. The distribution of their widths is a potential kinetic parameter independent of surface orientation and less susceptible to the factors, such as the sampling method and surface etch rate, that produce conflicting Dpar values.

Modeling the fission track etching process in apatite: Segmentation or crystallography influence

1995 ◽  
Vol 25 (1-4) ◽  
pp. 137-140 ◽  
Author(s):  
F. Villa ◽  
M. Grivet ◽  
M. Rebetez ◽  
C. Dubois ◽  
A. Chambaudet
Keyword(s):  
Fission Track ◽  
Etching Process ◽  
Track Etching

Calibration and simulation of apatite fission track etching: Influence of diffusion and crystal symmetry

1997 ◽  
Vol 28 (1-6) ◽  
pp. 543-548 ◽  
Author(s):  
F. Villa ◽  
M. Grivet ◽  
M. Rebetez ◽  
C. Dubois ◽  
A. Chambaudet
Keyword(s):  
Fission Track ◽  
Crystal Symmetry ◽  
Apatite Fission Track ◽  
Track Etching

scholarly journals Short communication concerning experimental factors affecting fission-track counts in apatite

2021 ◽  
Author(s):  
Carolin Aslanian ◽  
Raymond Jonckheere ◽  
Bastian Wauschkuhn ◽  
Lothar Ratschbacher
Keyword(s):  
Short Communication ◽  
Fission Track ◽  
Track Length ◽  
Severe Restriction ◽  
Related Factors ◽  
Factors Affecting ◽  
Provenance Studies ◽  
Etched Surface ◽  
Track Counts ◽  
Better Than

Abstract. The tools for interpreting fission-track data are evolving apace but, even so, the outcomes cannot be better than the data. Recent studies that have again taken up the issues of etching and observation have shown that both have an effect on confined-track length measurements. We report experiments concerning the effects of grain orientation, polishing, etching and observation on fission-track counts in apatite. The results cannot be generalized to circumstances other than those of the experiments, and thus do not solve the problems of track counting. Our findings nevertheless throw light on the factors affecting the track counts, and thence the sample ages, whilst raising the question: what counts as an etched surface track? This is pertinent to manual and automatic track counts and to designing training strategies for neural networks. We cannot be confident that counting prism faces and using the ζ-calibration for age calculation are adequate for dealing with all etching- and counting-related factors across all samples. Prism faces are not unproblematic for counting and other surface orientations are not per se useless. Our results suggest that a reinvestigation of the etching properties of different apatite faces could increase the range useful for dating, and so lift a severe restriction for provenance studies.

Studies on Headform Impact Design

2001 ◽  
Author(s):  
Anindya Deb
Keyword(s):  
Current Model ◽  
Relative Effectiveness ◽  
Trial And Error ◽  
Worst Case ◽  
New Approach ◽  
Geometrical Properties ◽  
Head Injury Criterion ◽  
Kinematic Relationship ◽  
Safety Compliance ◽  
Energy Absorbing

Abstract HIC(d) (Head Injury Criterion, dummy) is defined as a kinematic relationship involving resultant translational deceleration at the CG (center of gravity) of a biofidelic headform and duration of contact. As deceleration response of a headform is in general a function of the energy-absorbing and geometrical properties of an obstructing structure (for a given impact speed), HIC(d) can be expressed, at least symbolically, as a function of those properties. The current paper uses a simplified mathematical model to capture the worst case of headform impact as considered in the FMVSS 201 regulation for upper interior head impact. The obstructing structural countermeasure in the path of a colliding headform is assumed to possess idealized elastoplastic although physically relevant behavior under loading. During the process of designing for headform impact safety compliance, which often turns out to be a trial-and-error process, it is sometimes difficult to see the correspondence between HIC(d) and the relative effectiveness of design iterations in terms of energy-absorption. Thus, relationship between HIC(d) and energy absorbed by such structural countermeasures is investigated. Based on results obtained from the current model and a new approach, an explicit relationship is derived between HIC(d) and the characteristic properties of an energy-absorbing countermeasure that can be used as a design aid.

Fission track etching and annealing of tourmaline

1977 ◽  
Vol 1 (2) ◽  
pp. 145-148 ◽  
Author(s):  
Nand Lal ◽  
Rajinder Parshad ◽  
K.K. Nagpaul
Keyword(s):  
Fission Track ◽  
Track Etching

Lidar-Derived Distribution of Cloud Vertical Location and Extent

1995 ◽  
Vol 34 (1) ◽  
pp. 107-120 ◽  
Author(s):  
A. I. Carswell ◽  
A. Fong ◽  
S. R. Pal ◽  
I. Pribluda
Keyword(s):  
Statistical Analysis ◽  
Frequency Distributions ◽  
Geometrical Properties ◽  
Cloud Properties ◽  
Vertical Location ◽  
Other Information ◽  
Relationship Of ◽  
The Relationship ◽  
Cloud Thickness ◽  
532 Nm

Abstract This paper summarizes the results of a statistical analysis of lidar-determined cloud geometrical properties measured during the 1989 and 1991 campaigns of the Experimental Cloud Lidar Pilot Study. Useful lidar descriptors are introduced to specify the bottom-, top-, and midcloud altitudes. These are used to describe the behavior of cloud vertical location and vertical extent during several months of observations using a dual wavelength (1064 and 532 nm) Nd:YAG lidar at Toronto. Frequency distributions of cloud height and cloud thickness are presented and the relationship of the lidar descriptors to cloud properties are discussed. These data are compared with other information on cloud geometry available in the literature.

scholarly journals Theoretical Analysis of the Bladeless Wind Turbine Performance

2020 ◽  
pp. 93-106
Author(s):  
A. Anthony Adeyanju ◽  
D. Boucher
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Current Model ◽  
Vortex Formation ◽  
Angular Acceleration ◽  
Power Coefficient ◽  
Geometrical Properties ◽  
Structural Support ◽  
Wind Speeds ◽  
Lock In

A bladeless wind turbine utilizes vortex formation to extract energy from the wind. Vortex formation are small swirls of air which occur as a result of the geometric shape of the device. This study designed a bladeless wind turbine which incorporates a structural support at a distance offset from the center axis of the cylindrical mast. Springs were added to the final design as means to provide the stiffness required to obtain resonance with the vortex shedding frequency and to also assist in supporting the structure. The analysis was conducted at wind speeds 1m/s, 4m/s and 7m/s, where the geometrical properties of the device remained constant. MATLAB was used to analyze the equation of motion derived for the device. The variables of interest in the studies were mainly the angular acceleration, power coefficient and the resonant frequency. The results obtained showed that for wind speeds above and below the designed wind speed of 4m/s the angular velocity remained the same. Results of this model showed that high amplitudes occur only at resonance. Results showed that with the current power generating mechanism, the average efficiency attainable is approximately 2% at steady state. This is the theoretical efficiency which could be achieved based on the current model. It was discovered that for linearly tapered cylinders, increased oscillations occurred during the ‘lock-in range’ for a range of reduced velocities. The reduced velocity of the designed wind speed is approximately Vr = 5m/s. This value lies within the theoretical range lock in range where increased oscillations are expected to occur between reduced velocities of 4.75m/s and 8m/s [1].

Fission track etching and annealing phenomenon in phlogopite and their applications

1978 ◽  
Vol 15 (12) ◽  
pp. 1924-1929 ◽  
Author(s):  
Rajinder Parshad ◽  
H. S. Saini ◽  
K. K. Nagpaul
Keyword(s):  
Fission Track ◽  
Uranium Concentration ◽  
Etching Time ◽  
Fission Tracks ◽  
Mean Values ◽  
Annealing Temperatures ◽  
Track Etching ◽  
Correction Curve ◽  
The Mean ◽  
Annealing Experiments

Systematic annealing experiments on fission tracks in phlogopite have been carried out under standard etching conditions to obtain the correction curve for the ages of phlogopite, which might have been lowered due to geological annealing of fossil fission tracks. Variation of fission track density with etching time at different annealing temperatures has been analysed in order to standardize the etching conditions. All the tracks in phlogopite are annealed by heating at 590 °C for 1 h. Extrapolation of experimental data suggests that a temperature of 215 °C would be required for 1 Ma to remove all the tracks. The corrected age of a phlogopite sample from Neyyur village, Kanya Kumari District, India, is 395 ± 20 Ma. The mean values of fission fragment range for induced 235U fission tracks, uranium concentration, activation energy, and an effective paleoisotherm for fission track clock in the Neyyur village phlogopite are 17.7 ± 2.0 μm, 3.12 × 10−9 g/g, 1.8 eV, and 150 °C, respectively.

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