scholarly journals HEIDELBERG RADIOCARBON LAB – ESTABLISHING A NEW CARBON DIOXIDE EXTRACTION LINE FOR CARBONATE SAMPLES

Radiocarbon ◽  
2021 ◽  
pp. 1-10
Author(s):  
S Therre ◽  
L Proß ◽  
R Friedrich ◽  
M Trüssel ◽  
N Frank
Keyword(s):  
Radiocarbon Dating ◽  
Glass Tube ◽  
Extraction Process ◽  
High Accuracy ◽  
Repeated Measurements ◽  
Average Value ◽  
Carbon Dioxide Extraction ◽  
Favorable Conditions ◽  
Solid Piece ◽  
Environmental Physics

ABSTRACT To achieve high-precision and reproducible results from radiocarbon (14C) dating of carbonate samples in paleoclimate research, a new CO2 extraction line was designed, constructed, and characterized at the Heidelberg Radiocarbon Lab of the Institute of Environmental Physics, Heidelberg. The setup includes a circular glass-tube design, which is operated at vacuum pressure levels of the order of 10–5 mbar. The efficiency of the extraction process was assessed, showing significantly favorable conditions for solid piece samples (99.58 ± 4.69)% over powdered samples (88.28 ± 10.03)%. Process blank values are below 0.2 pMC apparent 14C activity. Repeated measurements of IAEA C2 standards with an average value of (41.09 ± 0.23) pMC attest high accuracy and reproducibility of the instrument. Six consecutive samples of 6 to 12 mg carbonate mass can be processed in one run of roughly 2.5 hours. Thus, the new setup contributes to time-efficient and reproducible radiocarbon dating results for paleoclimate research at the Institute of Environmental Physics. In a first application, Dead Carbon Fraction (DCF) values of a Holocene alpine stalagmite from Schratten Cave are presented, revealing extraordinarily high offsets between atmospheric and stalagmite 14C with DCF values between (49.4 ± 0.4)% and (61.6 ± 0.4)%.

scholarly journals Extracting image features for classification by two-tier genetic programming

2020 ◽  
Author(s):  
Harith Al-Sahaf ◽  
A Song ◽  
K Neshatian ◽  
Mengjie Zhang
Keyword(s):  
Genetic Programming ◽  
Image Classification ◽  
Domain Knowledge ◽  
Extraction Process ◽  
High Accuracy ◽  
Classification Performance ◽  
Image Features ◽  
Classification Methods ◽  
Feature Based ◽  
Second Tier

Image classification is a complex but important task especially in the areas of machine vision and image analysis such as remote sensing and face recognition. One of the challenges in image classification is finding an optimal set of features for a particular task because the choice of features has direct impact on the classification performance. However the goodness of a feature is highly problem dependent and often domain knowledge is required. To address these issues we introduce a Genetic Programming (GP) based image classification method, Two-Tier GP, which directly operates on raw pixels rather than features. The first tier in a classifier is for automatically defining features based on raw image input, while the second tier makes decision. Compared to conventional feature based image classification methods, Two-Tier GP achieved better accuracies on a range of different tasks. Furthermore by using the features defined by the first tier of these Two-Tier GP classifiers, conventional classification methods obtained higher accuracies than classifying on manually designed features. Analysis on evolved Two-Tier image classifiers shows that there are genuine features captured in the programs and the mechanism of achieving high accuracy can be revealed. The Two-Tier GP method has clear advantages in image classification, such as high accuracy, good interpretability and the removal of explicit feature extraction process. © 2012 IEEE.

Thread Friction Torque in Bolted Joints

2005 ◽  
Vol 127 (4) ◽  
pp. 387-393 ◽  
Author(s):  
Sayed A. Nassar ◽  
Payam H. Matin ◽  
Gary C. Barber
Keyword(s):  
Friction Coefficient ◽  
Current Practice ◽  
Weighted Average ◽  
High Accuracy ◽  
Friction Torque ◽  
Bolted Joints ◽  
Bolted Joint ◽  
Average Value ◽  
Highly Sensitive

In this paper, formulas are developed for the calculation of the effective thread friction radius in fasteners, in order to determine the thread friction torque component. Due to the lack of exact formulas in the literature, current practice uses the average value of the minor and major thread radii, as an approximation, for determining the thread friction torque component. Results provided by these formulas are compared with those given by the current practice that uses the average value of the minor and major thread radii, instead of the exact value. It is well known that the torque-tension relationship in threaded fastener applications is highly sensitive to the friction torque components: between threads, and under the turning fastener head or nut. Even moderate variations or inaccuracies in determining the friction torque components would significantly impact the fastener tension and the joint clamp load. High accuracy in the estimation of the friction torque components is critical, as it directly affects the reliability, safety, and the quality of bolted assemblies. This analysis focuses on the thread friction torque component. The new formulas for the thread friction radius are developed for a mathematical model of a bolted joint using five assumed scenarios of the contact pressure between male and female threads. Because of the fact that the variation in the sliding speed of various points on a thread surface is insignificant, a uniform thread friction coefficient is used in the analysis. However, a contact area weighted average value is used for the thread friction coefficient. Numerical results and error analysis are presented in terms of a single nondimensional variable, namely, the ratio between the major and minor thread radii.

Winter savory: Supercritical carbon dioxide extraction and mathematical modeling of extraction process

2016 ◽  
Vol 117 ◽  
pp. 89-97 ◽  
Author(s):  
Jelena Vladić ◽  
Zoran Zeković ◽  
Stela Jokić ◽  
Sandra Svilović ◽  
Strahinja Kovačević ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Extraction Process ◽  
Supercritical Carbon Dioxide Extraction ◽  
Carbon Dioxide Extraction ◽  
Supercritical Carbon

scholarly journals Efek Antidiare Ekstrak Etanol Daun Kelor (Moringa oleifera L.) Pada Mencit Putih Jantan

2020 ◽  
Vol 6 (1) ◽  
pp. 35-39
Author(s):  
Rizal Fauzi ◽  
◽  
Annisa Fatmawati ◽  
Emelda Emelda ◽  
◽  
...  
Keyword(s):  
Body Weight ◽  
Intestinal Motility ◽  
Moringa Oleifera ◽  
Ethanol Extract ◽  
Negative Control Group ◽  
Extraction Process ◽  
Negative Control ◽  
Control Group ◽  
Average Value ◽  
Normal Individuals

Diarrhea is an increase frequency and decrease consistency of fecal when compared with the bowel condition of normal individuals. The high incidence of acute and chronic diarrhea encourages researchers to keep trying to find new antidiarrheal drugs, especially from plants. The leaves of Moringa (Moringa oleifera Lam) contain tannins which are polyphenolic compounds and has benefits as anantidiarrheal.This study aims to determine the activity of the ethanol extract of moringa leaves as an antidiarrheal by looking at intestinal motility. The extraction process was carried out by maceration method using ethanol 70%..The result research is the average value of the treatment ratio is smaller than the negative control group. The average value of the ratio of the group was given by ethanol extract of moringa leaves at a dose of 9.1 mg / 20 g body weight was 0.664; ethanol extract of moringa leaves at dose of 18.2 mg / 20 g body weight was 0.434 and ethanol extract of moringa leaves at dose of 36.4 mg / 20 g body weight was 0.389. From this value, it is known that the ethanol extract of Moringa leaves has an antidiarrheal effect by inhibiting intestinal motility. The effect of the ethanol extract of Moringa leaves in inhibiting intestinal motility is best at a dose of 36.4 mg / 20 g body weight with an average value ratio of 0.389.

scholarly journals Wood quality and value production in mixed fir-spruce-beech stands: long-term research in the Western Carpathians

2016 ◽  
Vol 62 (2) ◽  
pp. 98-104 ◽  
Author(s):  
Rudolf Petráš ◽  
Julián Mecko ◽  
Michal Bošeľa ◽  
Vladimír Šebeň
Keyword(s):  
Wood Quality ◽  
Abies Alba ◽  
Repeated Measurements ◽  
Mixed Stands ◽  
Average Value ◽  
Mean Diameter ◽  
Stem Quality ◽  
The Mean ◽  
Value Production

Abstract Stem quality and damage was evaluated in mixed spruce-fir-beech stands. Moreover, an assortments structure was determined with their financial value. Results were compared with pure spruce (Picea abies [L.] Karst.), fir (Abies alba Mill.) and beech (Fagus sylvatica L.) stands. Repeated measurements on 31 long-term research plots, stand assortment models, assortment yield models and value yield models were used. Stem quality of fir and spruce was only slightly lower in mixed stands compared to pure stands but beech stem quality was considerably worse in mixed stands. Fir and spruce had slightly lower proportions of better IIIA quality logs and higher proportions of IIIB quality in mixed stands. Beech had worse assortment structure than spruce and fir, in general. Pure beech stands had higher proportions of better I–IIIA quality assortments than mixed stands by 1–7%. Fir and spruce average value production (€ m−3) culminated at about 56 and 62 cm mean diameters. Almost the same value production was found in pure stands. In these stands it culminated at the mean diameter of 58 and 60 cm. Beech produced substantially less value on the same sites. In mixed stands, its value production culminated at the mean diameter of 40 cm. In pure stands, it culminated at the mean diameter of 36 cm. Although the production was found to be similar in both mixed and pure forests, higher damage intensity and less stem quality in mixed forests suggest that the pure forests can be more profitable.

Optimization of Hydrodistillation of Rosemary Essential Oil

2020 ◽  
Vol 9 (3) ◽  
pp. 51-61
Author(s):  
Ouassila Larkeche ◽  
Ahmed Zermane ◽  
Abdeslam-Hassen Meniai ◽  
Souad Boubaira ◽  
Hayat Kouis ◽  
...  
Keyword(s):  
Essential Oil ◽  
Plant Material ◽  
Extraction Process ◽  
Extraction Time ◽  
Operating Parameters ◽  
Distillation Process ◽  
Yield Value ◽  
Water Plant ◽  
Carbon Dioxide Extraction ◽  
Oil Components

Extraction of essential oil from Algerian rosemary leaves is carried out by means of a hydro-distillation process. The important operating parameters such as extraction time, condensation flow rate and water/solid plant material ratio, have been investigated. The highest yield value was 1.92% and was obtained for a water/plant ratio, a condensate flowrate, and extraction time of 20, 4.51ml/min and 120 min, respectively. The essential oil components have been identified using the GCMS analysis which show camphor as the major ingredient, followed by camphene, α-pinene and 1,8-cineole. The results have been compared with those obtained using a supercritical carbon dioxide extraction process, which has shown to be more much better quantitatively and qualitatively.

Reply to the comment by Amano on “Linear and bent triatomic molecules are not qualitatively different!”

2021 ◽  
pp. 1-3
Author(s):  
Per Jensen
Keyword(s):  
Quantum Mechanics ◽  
Repeated Measurements ◽  
Moment Of Inertia ◽  
Molecular Axis ◽  
Linear Molecule ◽  
Triatomic Molecule ◽  
Expectation Value ◽  
Triatomic Molecules ◽  
Average Value ◽  
The Subject

In Amano’s comment on Jensen’s paper, we notice two important misconceptions: (i) Amano overlooks the fact that all features special for a linear molecule originate in the double degeneracy in the bending motion (i.e., in the fact that for a linear triatomic molecule, the description of the bending motion must necessarily also involve the rotation about the axis of least moment of inertia, the a axis, which becomes the molecular axis at equilibrium), and (ii) the expectation value generated from the wavefunction gives an “average” value of the relevant observable (coordinate); the expectation value can, in principle, be obtained experimentally as the average of very many repeated measurements of the observable. In our previous papers on this subject, in particular the paper by Jensen discussed here, we have attempted to explain our results as coherently and “pedagogically” as we can, starting with the fundamental principles of quantum mechanics, and we encourage interested readers to refer to our previous works on the subject. Thus, we maintain our assertion that the vibrationally averaged structure of a linear molecule is observed as being bent, as we have demonstrated previously from both theoretical and experimental viewpoints.

Effect of CO2 concentrations on acoustic inferences of airway area

1986 ◽  
Vol 60 (2) ◽  
pp. 398-401 ◽  
Author(s):  
A. D. D'Urzo ◽  
A. S. Rebuck ◽  
V. G. Lawson ◽  
V. Hoffstein
Keyword(s):  
Glass Tube ◽  
Co2 Concentration ◽  
Gas Mixtures ◽  
Repeated Measurements ◽  
Distance Functions ◽  
Axial Position ◽  
Gas Composition ◽  
Acoustic Reflection ◽  
Accuracy Of Measurements ◽  
Model Point

To determine the effect of gas composition on the accuracy of measurements of airway area and distance using an acoustic reflection technique, we employed glass-tube models to simulate pharyngeal (Phar-model), laryngeal (Lar-model), and tracheal (Trach-model) regions of upper and central airways. We made repeated measurements of area-distance functions using gas mixtures containing 0, 2, 4, 6, 8, and 10% CO2, 80% He, and balance O2. The actual area of the model was calculated from the roentgenographic data and compared favorably with an area measured by acoustic reflections using a gas mixture containing 0% CO2. With the different gas mixtures, calculated area was overestimated only at the highest levels of CO2, with Phar-model area increasing from (mean +/- SD) 4.66 +/- 0.03 cm2 measured with 0% CO2 to 4.93 +/- 0.05 cm2 (P less than 0.05) measured with CO2 concentration of 10%. To assess the effect of CO2 concentration on measurements of distance, we isolated two discrete points located in the Phar-model and Lar-model regions. When measurements were performed using 10% CO2 mixture, Phar-model point was shifted by 1.02 +/- 0.03 cm and Lar-model point was shifted by 2.16 +/- 0.09 cm away from the microphone compared with their axial position determined, using 0% CO2 mixture (P less than 0.05). Differences in area-distance calculations at the higher levels of CO2 did not exceed the within-run variability of the technique (10 +/- 4%). We conclude that CO2 absorbers are not required during measurements of airway area by acoustic reflections, provided CO2 concentration does not exceed 10%.

scholarly journals Radiocarbon Dating with the Utrecht Tandem Accelerator

Radiocarbon ◽  
1983 ◽  
Vol 25 (2) ◽  
pp. 739-744 ◽  
Author(s):  
K van der Borg ◽  
J A Hoogenboom ◽  
R A Jelmersma ◽  
Abraham Vermeer ◽  
Gert Hut
Keyword(s):  
Mass Spectrometry ◽  
Periodic System ◽  
Radiocarbon Dating ◽  
Isotope Ratios ◽  
High Accuracy ◽  
Important Application ◽  
Second Phase ◽  
Tandem Accelerator ◽  
Two Phases ◽  
Rapid Switching

In 1979 when accelerator mass spectrometry was started in the Netherlands, Gove (1978) and Litherland (1980) demonstrated that a tandem accelerator is eminently suited for this work. Isotope ratios below 10−15 could be determined and applications were stimulated on numerous fields of research. 14C dating in particular would become an important application because smaller samples could be employed and more complex dating problems could be attacked. However, the 5% accuracy reached at that time had to be improved towards the 0.5% obtained with the conventional method of counting decays. Purser and Hanley (1978) pointed out that this high accuracy could be reached in facilities especially dedicated to dating. Rapid switching between measurements on different isotopes turned out to be crucial (Suter et al, 1981). We decided to proceed in two phases. In the first phase, the existing EN-tandem facility would be used as before and modified for the detection of 14C ions. From measurements with 14C ions from different samples, information would be obtained about the limitations of the existing facility. In the second phase, this information would be used to develop a facility in which accurate measurements of isotope ratios can be performed for elements throughout the periodic system. Conventional 14C dating will be extended in collaboration with the Isotope Physics Laboratory in Groningen. Also, applications with other elements will be studied. The improved facility is scheduled for operation in the spring of 1983.

scholarly journals Extracting image features for classification by two-tier genetic programming

2020 ◽  
Author(s):  
Harith Al-Sahaf ◽  
A Song ◽  
K Neshatian ◽  
Mengjie Zhang
Keyword(s):  
Genetic Programming ◽  
Image Classification ◽  
Domain Knowledge ◽  
Extraction Process ◽  
High Accuracy ◽  
Classification Performance ◽  
Image Features ◽  
Classification Methods ◽  
Feature Based ◽  
Second Tier

Image classification is a complex but important task especially in the areas of machine vision and image analysis such as remote sensing and face recognition. One of the challenges in image classification is finding an optimal set of features for a particular task because the choice of features has direct impact on the classification performance. However the goodness of a feature is highly problem dependent and often domain knowledge is required. To address these issues we introduce a Genetic Programming (GP) based image classification method, Two-Tier GP, which directly operates on raw pixels rather than features. The first tier in a classifier is for automatically defining features based on raw image input, while the second tier makes decision. Compared to conventional feature based image classification methods, Two-Tier GP achieved better accuracies on a range of different tasks. Furthermore by using the features defined by the first tier of these Two-Tier GP classifiers, conventional classification methods obtained higher accuracies than classifying on manually designed features. Analysis on evolved Two-Tier image classifiers shows that there are genuine features captured in the programs and the mechanism of achieving high accuracy can be revealed. The Two-Tier GP method has clear advantages in image classification, such as high accuracy, good interpretability and the removal of explicit feature extraction process. © 2012 IEEE.

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