scholarly journals Ready for Screening: Fast Assessable Hydraulic and Anatomical Proxies for Vulnerability to Cavitation of Young Conifer Sapwood

Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1104
Author(s):  
Sabine Rosner ◽  
Sebastian Nöbauer ◽  
Klara Voggeneder
Keyword(s):  
Basic Density ◽  
Tangential Direction ◽  
Air Injection ◽  
Reliable Estimate ◽  
Conifer Species ◽  
Forest Dieback ◽  
Vulnerability To Cavitation ◽  
Plant Groups ◽  
Relative Water ◽  
Conductivity Loss

Research Highlights: novel fast and easily assessable proxies for vulnerability to cavitation of conifer sapwood are proposed that allow reliable estimation at the species level. Background and Objectives: global warming calls for fast and easily applicable methods to measure hydraulic vulnerability in conifers since they are one of the most sensitive plant groups regarding drought stress. Classical methods to determine P12, P50 and P88, i.e., the water potentials resulting in 12, 50 and 88% conductivity loss, respectively, are labour intensive, prone to errors and/or restricted to special facilities. Vulnerability proxies were established based on empirical relationships between hydraulic traits, basic density and sapwood anatomy. Materials and Methods: reference values for hydraulic traits were obtained by means of the air injection method on six conifer species. Datasets for potential P50 proxies comprised relative water loss (RWL), basic density, saturated water content as well as anatomical traits such as double wall thickness, tracheid lumen diameter and wall/lumen ratio. Results: our novel proxy P25W, defined as 25% RWL induced by air injection, was the most reliable estimate for P50 (r = 0.95) and P88 (r = 0.96). Basic wood density (r = −0.92), tangential lumen diameters in earlywood (r = 0.88), wall/lumen ratios measured in the tangential direction (r = −0.86) and the number of radial cell files/mm circumference (CF/mm, r = −0.85) were also strongly related to P50. Moreover, CF/mm was a very good predictor for P12 (r = −0.93). Conclusions: the proxy P25W is regarded a strong phenotyping tool for screening conifer species for vulnerability to cavitation assuming that the relationship between RWL and conductivity loss is robust in conifer sapwood. We also see a high potential for the fast and easily applicable proxy CF/mm as a screening tool for drought sensitivity and for application in dendroecological studies that investigate forest dieback.

A novel approach for fast prediction of hydraulic vulnerability in conifers

2020 ◽  
Author(s):  
Sabine Rosner ◽  
Klara Voggeneder ◽  
Sebastian Nöbauer
Keyword(s):  
Water Loss ◽  
Empirical Relationship ◽  
Conifer Species ◽  
Percent Loss ◽  
Novel Approach ◽  
Plant Groups ◽  
Hydraulic Vulnerability ◽  
Relative Water ◽  
Wood Traits ◽  
Fast Prediction

<p>Global warming calls for fast and easily applicable methods to measure hydraulic vulnerability in conifers since they are one of the most sensitive plant groups regarding drought stress. Classical methods to determine P<sub>50</sub>, i.e. the water potential resulting in 50% conductivity loss, are labor intensive and prone to errors. In this study, the empirical relationship between percent loss of hydraulic conductivity and relative water loss in sapwood of six conifer species was used to establish a novel proxy for P<sub>50</sub>. Our new proxy P<sub>25W</sub>, defined as 25% of relative water loss induced by air injection, is easy and fast to measure and correlates strongly with P<sub>50</sub> (r = 0.95) as well as with functional wood traits such as the tracheid wall/lumen ratio (r = -0.87). The method is regarded as a strong new phenotyping tool for screening trees for drought sensitivity.</p>

The Effect of Air Injector on the Performance of Airlift

2012 ◽  
Vol 516-517 ◽  
pp. 1022-1027 ◽  
Author(s):  
Dong Hu ◽  
Chuan Lin Tang ◽  
Feng Hua Zhang
Keyword(s):  
Flow Rate ◽  
Marked Effect ◽  
Pipe Wall ◽  
Tangential Direction ◽  
Air Injection ◽  
Air Flow Rate ◽  
Injection Angle ◽  
Injection Methods ◽  
The One ◽  
Air Lift

In order to investigate the air injection method on the performance of an airlift. For this purpose an air lift system with a riser 2000 mm long and 80 mm in diameter, was designed and tested. Seven different air injection methods were used at a constant submergence. The experimental results showed a marked effect on the airlift performance when operated with different air injection methods. The arrangement of five nozzles gives the best performance, and the one nozzle is the worst. Although the injection angle has a little effect on the airlift performance, but view the general conclusions as a whole, the best lifting efficiency can be obtained when the angle of the nozzle placed along the tangential direction of pipe wall is equal to 10º at a given air flow rate QG =37m3/h.

scholarly journals Vulnerability to cavitation inOlea europaeacurrent-year shoots: further evidence of an open-vessel artifact associated with centrifuge and air-injection techniques

2014 ◽  
Vol 152 (3) ◽  
pp. 465-474 ◽  
Author(s):  
José M. Torres-Ruiz ◽  
Hervé Cochard ◽  
Stefan Mayr ◽  
Barbara Beikircher ◽  
Antonio Diaz-Espejo ◽  
...  
Keyword(s):  
Air Injection ◽  
Vulnerability To Cavitation ◽  
Injection Techniques

Improvement to the air-injection technique to estimate xylem vulnerability to cavitation

Trees ◽  
2011 ◽  
Vol 25 (4) ◽  
pp. 705-710 ◽  
Author(s):  
Mustapha Ennajeh ◽  
Mourad Nouiri ◽  
Habib Khemira ◽  
Hervé Cochard
Keyword(s):  
Air Injection ◽  
Injection Technique ◽  
Vulnerability To Cavitation ◽  
Xylem Vulnerability

Optimization of the Efficiency of Stall Control Using Air Injection for Centrifugal Compressors—Additional Findings

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Taher Halawa
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Gas Turbines ◽  
Stable Condition ◽  
Tangential Direction ◽  
Air Injection ◽  
Centrifugal Compressors ◽  
Injection Angle ◽  
Stall Control

This study presents additional important findings to the results of the research paper; “Optimization of the efficiency of stall control using air injection for centrifugal compressors” published in the Journal of Engineering for Gas Turbines and Power in 2015 (Halawa, T., Gadala, M. S., Alqaradawi, M., and Badr, O., 2015, “Optimization of the Efficiency of Stall Control Using Air Injection for Centrifugal Compressors,” ASME J. Eng. Gas Turbines Power, 137(7), p. 072604). The aim of this study is to make a fine determination of the injection angle, which provides the best stable condition when the compressor operates close to stall condition. A relatively narrower range of injection angles with smaller intervals was selected comparing to the results of the referred published paper, which clarified that the best injection angle is 30 deg. External air was injected close to the diffuser entrance at the shroud surface. Injection was applied with mass flow rate equals 1.5% of the design compressor inlet mass flow rate with injection angles ranged from 16 deg to 34 deg measured from the tangential direction at the vaneless region. It was found that both of injection angles of 28 deg and 30 deg achieved the best results in terms of compressor stabilization but each one of them has a specific advantage comparing to the other one. Using injection angle of 28 deg provided the lowest kinetic energy losses while the best orientation of the fluid through diffuser resulted when using an injection angle of 30 deg.

scholarly journals The conifer-curve: fast prediction of hydraulic conductivity loss and vulnerability to cavitation

2019 ◽  
Vol 76 (3) ◽  
Author(s):  
Sabine Rosner ◽  
Daniel M. Johnson ◽  
Klara Voggeneder ◽  
Jean-Christophe Domec
Keyword(s):  
Hydraulic Conductivity ◽  
Vulnerability To Cavitation ◽  
Fast Prediction ◽  
Conductivity Loss

scholarly journals Prediction of hydraulic conductivity loss from relative water loss: new insights into water storage of tree stems and branches

2018 ◽  
Vol 165 (4) ◽  
pp. 843-854 ◽  
Author(s):  
Sabine Rosner ◽  
Berthold Heinze ◽  
Tadeja Savi ◽  
Guillermina Dalla‐Salda
Keyword(s):  
Hydraulic Conductivity ◽  
Water Loss ◽  
Water Storage ◽  
Relative Water ◽  
Conductivity Loss

Optimization of the Efficiency of Stall Control Using Air Injection for Centrifugal Compressors

2015 ◽  
Vol 137 (7) ◽  
Author(s):  
Taher Halawa ◽  
Mohamed S. Gadala ◽  
Mohamed Alqaradawi ◽  
Osama Badr
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
High Speed ◽  
Tangential Direction ◽  
Air Injection ◽  
Reversed Flow ◽  
Force Fluctuations ◽  
Injection Control ◽  
Stall Control

Numerical investigation of the optimization of the stall control efficiency for a high speed centrifugal compressor using air injection is presented. External air was injected close to the diffuser entrance at the shroud surface of the vaneless region. Injection was applied with mass flow rates of 0.7%, 1%, and 1.5% of the design inlet mass flow rate with six different angles of 0 deg, 10 deg, 20 deg, 30 deg, 40 deg, and 180 deg measured from the positive tangential direction at the vaneless region. Detailed comparisons were made between the case without using air injection and the different air injection cases by comparing velocity, pressure, and force fluctuations with time. Results showed that as the injection mass flow rate increases, the number of diffuser passages with reversed flow decreases for all cases of injection except for the case of reverse tangent injection. Results indicated that using angle of injection of 30 deg minimized the stall area and provided the least force fluctuations with no reversed flow compared to other injection angles. Finally, it was found that injecting air with mass flow rate of 1.5% of the inlet mass flow rate at an angle of 30 deg resulted in shifting of stall onset to a mass flow rate corresponding to 3.8 kg/s instead of 4 kg/s for a compressor without using air injection control.

Reliability of the Minimum Masking Level as Outcome Variable in Tinnitus Clinical Research

2020 ◽  
Vol 29 (3) ◽  
pp. 429-435
Author(s):  
Patricia C. Mancini ◽  
Richard S. Tyler ◽  
Hyung Jin Jun ◽  
Tang-Chuan Wang ◽  
Helena Ji ◽  
...  
Keyword(s):  
Standard Deviation ◽  
High Frequency ◽  
Pearson Correlation ◽  
Correlation Coefficients ◽  
Outcome Variable ◽  
Reliable Estimate ◽  
Moderate Correlation ◽  
Trained Subjects ◽  
The Relationship ◽  
Minimum Intensity

Purpose The minimum masking level (MML) is the minimum intensity of a stimulus required to just totally mask the tinnitus. Treatments aimed at reducing the tinnitus itself should attempt to measure the magnitude of the tinnitus. The objective of this study was to evaluate the reliability of the MML. Method Sample consisted of 59 tinnitus patients who reported stable tinnitus. We obtained MML measures on two visits, separated by about 2–3 weeks. We used two noise types: speech-shaped noise and high-frequency emphasis noise. We also investigated the relationship between the MML and tinnitus loudness estimates and the Tinnitus Handicap Questionnaire (THQ). Results There were differences across the different noise types. The within-session standard deviation averaged across subjects varied between 1.3 and 1.8 dB. Across the two sessions, the Pearson correlation coefficients, range was r = .84. There was a weak relationship between the dB SL MML and loudness, and between the MML and the THQ. A moderate correlation ( r = .44) was found between the THQ and loudness estimates. Conclusions We conclude that the dB SL MML can be a reliable estimate of tinnitus magnitude, with expected standard deviations in trained subjects of about 1.5 dB. It appears that the dB SL MML and loudness estimates are not closely related.

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