scholarly journals Corrections to Kusnetz method for measurements of radon progeny concentrations in air

2021 ◽  
Vol 16 (12) ◽  
pp. T12014
Author(s):  
O. Nusair
Keyword(s):  
Sampling Period ◽  
Sampling Time ◽  
Radon Progeny ◽  
Gross Alpha ◽  
Quick Method ◽  
Counting Period ◽  
Absorption Correction ◽  
Counting Time ◽  
Instantaneous Sampling ◽  
Sample Measurement

Abstract In 1956, H.L. Kusnetz proposed a quick method for radon progeny concentration measurement in mine atmosphere using a single gross-alpha count of a membrane-filtered air. The method is still widely used today and is based on a number of impractical assumptions. An instantaneous sampling time (less than ten seconds), is one of these assumptions that ignores the build-up and decay of the progeny on the filter paper during the sampling period, which is typically in the order of a few minutes. Of special concern is the 214Bi decay during the sampling period, since 214Po's alphas are lost during the sampling time and cannot be accounted for during the counting time. In addition, the method assumes that 214Bi activity during the counting period is constant. This inaccurate assumption can result in a smaller count rate, especially when counting times are long. Hence, underestimated working levels are expected when using Kusnetz factors without correcting for the sampling and counting times. In this technical report, exact sampling and counting time corrections to the method are provided along with the updated Kusnetz factors that correspond to common equilibrium conditions to correctly estimate the Working Level in air. Additionally, time corrections to the commonly used self-absorption correction formula and the lower level of detectability (LLD) equation used for any sample measurement are given.

Effect of Environmental Temperature on Diurnal Variation of Blood Constituents in the Bovine

1958 ◽  
Vol 195 (1) ◽  
pp. 88-90 ◽  
Author(s):  
R. H. Diven ◽  
H. M. Page ◽  
E. S. Erwin ◽  
C. B. Roubicek
Keyword(s):  
Inverse Relationship ◽  
Environmental Temperature ◽  
Plasma Cholesterol ◽  
Sampling Period ◽  
Sampling Time ◽  
Total Serum Protein ◽  
Total Serum ◽  
Blood Constituents ◽  
Consistent Relationship ◽  
Blood Creatinine

Five yearling Hereford steers were maintained in the open sunlight for three sampling periods; each period separated by 7 days. Feed was withheld during the sampling periods and water was restricted throughout the second sampling period. Whereas total serum protein varied directly in a linear fashion, blood creatinine, plasma cholesterol and carotene showed an inverse relationship with environmental temperature. A consistent relationship existed between time of sampling and plasma carotene concentration. Statistical analyses failed to show a consistent relationship between sampling time or temperature and levels of uric acid and glucose.

A New Method Based on Lyapunov Exponent to Determine the Threshold of Chaotic Systems

2014 ◽  
Vol 511-512 ◽  
pp. 329-333
Author(s):  
Yang Liu ◽  
Xin Chun Zhang
Keyword(s):  
Lyapunov Exponent ◽  
Chaotic Systems ◽  
Sampling Period ◽  
Qr Decomposition ◽  
Sampling Time ◽  
Duffing Equation ◽  
Experimental Results ◽  
New Method ◽  
Critical Threshold ◽  
Periodic Signals

The Duffing equation has been widely used to detect weak periodic signals. The transition threshold is the key to detect. Unfortunately, there is no effective method to determine the critical threshold. To solve this problem, a new method based on the QR decomposition to calculate Lyapunov exponent is presented. The accuracy of the algorithm will gradually improve with the sampling time increasing or the sampling period decreasing. The experimental results show that the method can determine the interval which contains the threshold, and detect the mutation acts of chaotic systems.

scholarly journals Identification of the Appropriate Leaf Sampling Period for Nutrient Analysis in ‘Hass’ Avocado

HortScience ◽  
2015 ◽  
Vol 50 (1) ◽  
pp. 130-136 ◽  
Author(s):  
Samuel Salazar-García ◽  
Isidro J.L. González-Durán ◽  
Martha E. Ibarra-Estrada
Keyword(s):  
Sampling Period ◽  
Leaf Length ◽  
Sampling Time ◽  
Nutrient Concentrations ◽  
Mathematical Functions ◽  
Nutrient Analysis ◽  
Leaf Sampling ◽  
Optimum Period ◽  
Macro And Micronutrients ◽  
Hass Avocado

This research was carried out from 2004 to 2005 in two commercial ‘Hass’ avocado orchards cultivated under rainfed conditions in a hot subhumid climate of the state of Nayarit, Mexico. The objectives of this study were to: 1) establish the patterns in nutrient concentrations during the lifespan of winter and summer vegetative flush leaves; and 2) validate a methodology based on mathematical functions to identify the appropriate period for leaf sampling to diagnose plant nutrition in avocado considering its two major vegetative flushes. Leaf samples were taken monthly for each vegetative flush, starting when leaf length was 5 cm or greater and concluding at leaf abscission. Starting at vegetative budbreak, winter and summer leaves lived 12.5 and 7.8 months, respectively. Summer flush leaves grew faster and attained greater length than winter leaves. A mathematical model based on the concentration of macro- and micronutrients through the lifespan of avocado leaves was evaluated. This model was used to determine the period when nutrient concentrations became stable and, consequently, to identify the proper leaf sampling period. For the ‘Hass’ avocado in Nayarit, the period for sampling winter flush leaves corresponded to 6.6- to 7.9-month-old leaves (4 Sept. to 13 Oct.). For summer leaves the optimum period was shorter and occurred when leaves were 3.9 to 4.9 months old (5 Dec. to 5 Jan.). The procedure and sampling time obtained here should be tested in other regions.

Effect of plant age on the critical inorganic and total phosphorus concentrations in selected tissues of subterranean clover (cv. Trikkala)

1992 ◽  
Vol 43 (1) ◽  
pp. 215 ◽  
Author(s):  
DC Lewis
Keyword(s):  
Subterranean Clover ◽  
Sampling Period ◽  
Sampling Time ◽  
Plant Age ◽  
Diagnostic Laboratory ◽  
Inorganic P ◽  
Critical Concentrations ◽  
Whole Plant ◽  
Study Support ◽  
Total P

Subterranean clover (cv. Trikkala) was grown in field and glasshouse experiments to calibrate the critical concentrations of inorganic P in selected plant tissues, for maximizing vegetative growth. Critical concentrations of total P in the various tissues were also calibrated from the field experiment. Critical concentrations of inorganic P derived in the glasshouse, for both youngest open leaf (YOL) and next oldest leaf (YOL+1), were similar at any one sampling time, but declined markedly with plant age, i.e. critical concentrations for YOL declined from 196 mg kg-1 at the first sampling to 96 mg kg-1 1 month later. Similarly, critical inorganic P concentrations for YOL derived in the field declined with time, i.e. from 187 mg kg-1 to 124 mg kg-1 from the first to second sampling. Critical inorganic P concentrations for YOL+1 were less age dependent, though much lower at any one sampling time. As such, inorganic P is not recommended for diagnostic laboratory use. Critical concentrations of total P for YOL and YOL+1 did not decline significantly over the sampling period, while those for whole plant tops (WT) declined from 0.35 to 0.30% over the same period. In the YOL tissue, the proposed critical nutrient range for total P is 0.40-0.45% while that for WT, sampled early in the growing season, is 0.35-0.40%. Results from this study support the use of total P in diagnostic plant testing services.

METHODOLOGY FOR SIMPLE SPOT MEASUREMENT OF EQUILIBRIUM EQUIVALENT RADON CONCENTRATION

2020 ◽  
Vol 191 (4) ◽  
pp. 383-390
Author(s):  
Akihiro Sakoda ◽  
Yuu Ishimori ◽  
Norie Kanzaki ◽  
Hiroshi Tanaka
Keyword(s):  
Calibration Curve ◽  
Present Method ◽  
Alpha Particles ◽  
Radon Progeny ◽  
Gross Alpha ◽  
Inhalation Dose ◽  
The Core ◽  
Activity Concentrations ◽  
Simple Sampling ◽  
Over Time

Abstract Estimation of the effective inhalation dose of short half-life radon progeny requires the quantification of radon equilibrium equivalent activity concentrations (EEC, Ceq). The aim of the present study is to develop new methodology that focuses on spot measurements to determine EEC from single gross alpha counts and determine an optimised protocol. The core of the approach is to measure alpha particles over time when the radon progeny attached to the sampling filter are significantly disintegrated. The calibration curve of single counts to EEC is theoretically deduced and validated by a comparison test. The advantage of the present method is its minimal requirements, including the use of common instruments and simple sampling, alpha counting and analysis procedures. This approach offers an option for radon practitioners working in a variety of fields, as well as the possibility for non-experts to easily measure Ceq.

Robust vibration control of a flexible arm subjected to torque disturbance

2006 ◽  
Vol 220 (2) ◽  
pp. 149-158 ◽  
Author(s):  
S-B Choi
Keyword(s):  
Vibration Control ◽  
Sliding Mode ◽  
Sampling Period ◽  
Sampling Time ◽  
Sliding Mode Controller ◽  
Control Input ◽  
Experimental Realization ◽  
Average Value ◽  
Flexible Arm ◽  
Single Link

This paper presents a perturbation estimator in sliding mode control system and applies it to vibration control of a flexible arm subjected to torque disturbance. The proposed estimator is featured by an integrated average value of the imposed perturbation over a certain sampling period. By implementing this type of estimator, undesirable chattering phenomenon can be effectively alleviated in the estimation process. In addition, the proposed method offers a flexibility for tuning the ratio of the estimation sampling time to the control input sampling time. In order to demonstrate the effectiveness of the proposed methodology, a single-link flexible arm is constructed. After formulating the governing equation of motion, a sliding mode controller which is integrated with the proposed estimator is designed. Vibration control performances of the flexible arm subjected to sinusoidal torque disturbances are evaluated through both computer simulation and experimental realization.

scholarly journals Seed removal by ants in Brazilian savanna: optimizing fieldwork

Sociobiology ◽  
2018 ◽  
Vol 65 (2) ◽  
pp. 155 ◽  
Author(s):  
Marina Acero Angotti ◽  
Ananza Rabello ◽  
Graziele Santiago ◽  
Carla Ribas
Keyword(s):  
Sampling Period ◽  
Exposure Period ◽  
Sampling Time ◽  
Brazilian Savanna ◽  
Future Research ◽  
Seed Removal ◽  
Artificial Seeds ◽  
Night Time ◽  
Different Types ◽  
Time Periods

There has been an increase in the number of studies using seed removal by ants to evaluate ecosystem functioning; however, these studies encompassed varying time periods and used different types of seeds. Therefore, our aim was to evaluate differences in the proportion of seeds removed by ants in impacted and non-impacted sites in Brazilian savanna. Furthermore, we evaluated seed removal (1) during the morning and after a 24h period of seed exposure and (2) using natural and artificial seeds (manipulated resource to resemble natural seeds). The proportion of seeds removed was higher after the 24h exposure period (artificial seeds) regardless of site status, and more artificial seeds were removed than natural seeds. Our recommendations regarding sampling period depend on whether evaluating impacted or non-impacted sites. Although seed removal was greater after 24h in both impacted and non-impacted sites, we suggest that research evaluating the proportion of seeds removed in non-impacted sites should be performed only in the morning period to optimize the sampling time (removal of 60% during this period). When the aim is to compare non-impacted and impacted sites, we suggest evaluating after 24h of exposure, since the impacted sites experienced a higher proportion of seed removal during the afternoon and/or night time periods. Furthermore, we recommend the use of artificial seeds because they are easier to obtain and manipulate, and allow us to do comparisons between studies at different regions. We consider these findings an important first step towards standardizing future research on seed removal in Brazilian savannas by facilitating fieldwork and allowing comparisons to be made among different studies.

Gaussian ϕ(ρz) curves: Comparison with other models

1990 ◽  
Vol 48 (2) ◽  
pp. 192-193
Author(s):  
Alberto Riveros ◽  
Gustavo Castellano
Keyword(s):  
Good Description ◽  
Bulk Sample ◽  
Incident Electron Energy ◽  
Power Mean ◽  
General Shape ◽  
Ionization Cross ◽  
X Ray ◽  
Mass Absorption ◽  
Absorption Correction ◽  
Image Position

X ray characteristic intensity Ii , emerging from element i in a bulk sample irradiated with an electron beam may be obtained throughwhere the function ϕi(ρz) is the distribution of ionizations for element i with the mass depth ρz, ψ is the take-off angle and μi the mass absorption coefficient to the radiation of element i.A number of models has been proposed for ϕ(ρz), involving several features concerning the interaction of electrons with matter, e.g. ionization cross section, stopping power, mean ionization potential, electron backscattering, mass absorption coefficients (MAC’s). Several expressions have been developed for these parameters, on which the accuracy of the correction procedures depends.A great number of experimental data and Monte Carlo simulations show that the general shape of ϕ(ρz) curves remains substantially the same when changing the incident electron energy or the sample material. These variables appear in the parameters involved in the expressions for ϕ(ρz). A good description of this function will produce an adequate combined atomic number and absorption correction.

point-Analysis Using the Extrapolation Method in the Analytical Electron microscope

1990 ◽  
Vol 48 (2) ◽  
pp. 430-431
Author(s):  
Zenji Horita ◽  
Ryuzo Nishimachi ◽  
Takeshi Sano ◽  
Minoru Nemoto
Keyword(s):  
Electron Microscope ◽  
Extrapolation Method ◽  
X Ray ◽  
Absorption Correction ◽  
Point Analysis ◽  
Analytical Electron ◽  
Analytical Electron Microscope ◽  
Data Points ◽  
Identical Composition ◽  
X Ray Absorption

Absorption correction is often required in quantitative x-ray microanalysis of thin specimens using the analytical electron microscope. For such correction, it is convenient to use the extrapolation method[l] because the thickness, density and mass absorption coefficient are not necessary in the method. The characteristic x-ray intensities measured for the analysis are only requirement for the absorption correction. However, to achieve extrapolation, it is imperative to obtain data points more than two at different thicknesses in the identical composition. Thus, the method encounters difficulty in analyzing a region equivalent to beam size or the specimen with uniform thickness. The purpose of this study is to modify the method so that extrapolation becomes feasible in such limited conditions. Applicability of the new form is examined by using a standard sample and then it is applied to quantification of phases in a Ni-Al-W ternary alloy.The earlier equation for the extrapolation method was formulated based on the facts that the magnitude of x-ray absorption increases with increasing thickness and that the intensity of a characteristic x-ray exhibiting negligible absorption in the specimen is used as a measure of thickness.

A Pilot Study of Mobile Telephone Message Interventions with Suicide Attempters in China

Crisis ◽  
2010 ◽  
Vol 31 (2) ◽  
pp. 109-112 ◽  
Author(s):  
Hui Chen ◽  
Brian L. Mishara ◽  
Xiao Xian Liu
Keyword(s):  
Pilot Study ◽  
Effective Means ◽  
Text Message ◽  
Text Messages ◽  
Mobile Telephone ◽  
Future Research ◽  
Quick Method ◽  
Suicide Attempters ◽  
To Receive

Background: In China, where follow-up with hospitalized attempters is generally lacking, there is a great need for inexpensive and effective means of maintaining contact and decreasing recidivism. Aims: Our objective was to test whether mobile telephone message contacts after discharge would be feasible and acceptable to suicide attempters in China. Methods: Fifteen participants were recruited from suicide attempters seen in the Emergency Department in Wuhan, China, to participate in a pilot study to receive mobile telephone messages after discharge. All participants have access to a mobile telephone, and there is no charge for the user to receive text messages. Results: Most participants (12) considered the text message contacts an acceptable and useful form of help and would like to continue to receive them for a longer period of time. Conclusions: This suggests that, as a low-cost and quick method of intervention in areas where more intensive follow-up is not practical or available, telephone messages contacts are accessible, feasible, and acceptable to suicide attempters. We hope that this will inspire future research on regular and long-term message interventions to prevent recidivism in suicide attempters.

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