scholarly journals The δ30Si peak value discovered in middle Proterozoic chert and its implication for environmental variations in the ancient ocean

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
T. P. Ding ◽  
J. F. Gao ◽  
S. H. Tian ◽  
C. F. Fan ◽  
Y. Zhao ◽  
...  
Keyword(s):  
Environmental Variations ◽  
Peak Value ◽  
Middle Proterozoic

The heritability of mental traits in humans: A proposal for a more coherent discussion

2003 ◽  
Vol 62 (1) ◽  
pp. 5-10 ◽  
Author(s):  
Manfred Velden
Keyword(s):  
Heritability Estimate ◽  
Environmental Variations ◽  
Heritability Estimates

It is proposed to simplify the debate about the heritability of mental traits in humans by concentrating on two crucial issues: Population specificity of heritability estimates and the relation of these estimates to the malleability of the trait to which they refer. It is demonstrated that due to vast differences between the environmental variations of populations there would have to be a heritability estimate for every imaginable population, and that a heritability estimate allows no predictions whatsoever about the malleability of the trait in question. It is therefore concluded that this field of research should be abandoned.

A novel analytical calculation of magnetic field in the slotted air gap of spoke-type permanent-magnet machines using conformal mapping

2020 ◽  
pp. 1-15
Author(s):  
Jianqi Li ◽  
Yu Zhou ◽  
Jianying Li
Keyword(s):  
Magnetic Field ◽  
Conformal Mapping ◽  
Permanent Magnet ◽  
Flux Density ◽  
Analytical Method ◽  
Electromotive Force ◽  
Analytical Calculation ◽  
Air Gap ◽  
Permanent Magnet Machines ◽  
Peak Value

This paper presented a novel analytical method for calculating magnetic field in the slotted air gap of spoke-type permanent-magnet machines using conformal mapping. Firstly, flux density without slots and complex relative air-gap permeance of slotted air gap are derived from conformal transformation separately. Secondly, they are combined in order to obtain normalized flux density taking account into the slots effect. The finite element (FE) results confirmed the validity of the analytical method for predicting magnetic field and back electromotive force (BEMF) in the slotted air gap of spoke-type permanent-magnet machines. In comparison with FE result, the analytical solution yields higher peak value of cogging torque.

Experimental Research on Damages Detection of Pipeline Structure by Using PZT-Based Waves

2011 ◽  
Author(s):  
Shi Yan ◽  
Binbin He ◽  
Naizhi Zhao
Keyword(s):  
Damage Detection ◽  
Lead Zirconate Titanate ◽  
Smart Materials ◽  
Arrival Time ◽  
Mode Conversion ◽  
Guided Wave ◽  
The Other ◽  
Damage Location ◽  
The Waves ◽  
Peak Value

Pipeline structure may generate damages during its service life due to the influence of environment or accidental loading. The damages need to be detected and repaired if they are severe enough to influence the transportation work. Non-destructive detection using smart materials combined with suitable diagonal algorithms are widely used in the field of structural health monitoring (SHM). Piezoelectric ceramics (such as Lead Zirconate Titanate, PZT) is one of the smart materials to be applied in the SHM due to the piezoelectric effect. So far, the PZT-based wave method is widely used for damage detection of structures, in particular, pipeline structures. A series of piezoelectric patches are bonded on the surface of the pipeline structure to monitor the damages such as local crack or effective area reduction due to corrosion by using diagonal waves. The damage of the pipeline structure can be detected by analysis of the received diagonal waves which peak value, phase, and arriving time can be deferent from the health ones. The response of the diagonal wave is not only correlated to the damage location through estimation of the arrival time of the wave peak, but also associated with the peak value of the wave for the reduction of wave energy as the guided wave passing through the damages. Therefore, the presence of damages in the pipeline structure can be detected by investigating the parameter change of the guided waves. The change of the wave parameters represents the attenuation, deflection and mode conversion of the waves due to the damages. In addition, the guided wave has the ability of quick detecting the damage of the pipeline structure and the simplicity of generating and receiving detection waves by using PZT patches. To verify the proposed method, an experiment is designed and tested by using a steel pipe bonded the PZT patches on the surface of it. The PZT patches consist of an array to estimate the location and level of the damage which is simulated by an artificial notch on the surface of the structure. The several locations and deep heights of the notches are considered during the test. A pair of the PZT patches are used at the same time as one is used as an actuator and the other as a sensor, respectively. A tone burst of 5 cycles of wave shape is used during the experiment. A wave generator is applied to create the proposed waves, and the waves are amplified by an amplifier to actuate the PZT patch to emit the diagonal waves with appropriately enough energy. Meanwhile, the other PZT patch is used as a sensor to receive the diagonal signals which contain the information of the damages for processing. For data processing, an index of root mean square deviation (RMSD) of the received data is used to estimate the damage level by compare of the data between the damaged and the health peak valves of the received signals. The time reversal method which aimed at increasing the efficiency of the detection is also used to detect the damage location by estimating the arrival time of the reflected wave passing with a certain velocity. The proposed method experimentally validates that it is effective for application in damage detection of pipeline structure.

scholarly journals Analysis method of the cavitation vibration signals in poppet valve based on EEMD

2021 ◽  
Vol 13 (2) ◽  
pp. 168781402199811
Author(s):  
Beibei Li ◽  
Qiao Zhao ◽  
Huaiyi Li ◽  
Xiumei Liu ◽  
Jichao Ma ◽  
...  
Keyword(s):  
Ensemble Empirical Mode Decomposition ◽  
Center Frequency ◽  
Analysis Method ◽  
Vibration Signals ◽  
Poppet Valve ◽  
Mode Decomposition ◽  
Marginal Spectrum ◽  
Cavitation Intensity ◽  
Eemd Method ◽  
Peak Value

To study the vibration characteristics of the poppet valve induced by cavitation, the signal analysis method based on the ensemble empirical mode decomposition (EEMD) method was studied experimentally. The component induced by cavitation was separated from the vibration signals through the EEMD method. The results show that the IMF2 component has the largest amplitude and energy of all components. The root mean square (RMS) value, peak value of marginal spectrum, and center frequency of marginal spectrum of the IMF2 component were studied in detail. The RMS value and the peak value of the marginal spectrum decrease with a decrease of cavitation intensity. The center frequency of marginal spectrum is between 12 kHz and 20 kHz, and the center frequency first increases and then decreases with a decrease of cavitation intensity. The change rate of the center frequency also decreases with an increase of inlet pressure.

scholarly journals Box Experiment Study of Thermally Enhanced SVE for Benzene

2021 ◽  
Vol 18 (8) ◽  
pp. 4062
Author(s):  
Qixiang Zhang ◽  
Qiyan Feng ◽  
Xueqiang Zhu ◽  
Mei Zhang ◽  
Yanjun Wang ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Concentration Distribution ◽  
Average Concentration ◽  
Soil Gas ◽  
Vapor Extraction ◽  
Operation Process ◽  
Repair Efficiency ◽  
Benzene Concentration ◽  
Benzene Content ◽  
Peak Value

In order to describe the changes of soil temperature field, air flow field and remediation situation with time during the process of thermally enhanced SVE (soil vapor extraction), a remediation experiment of benzene contaminated soil with single extraction pipe was carried out in a box device. The results showed that the whole temperature of the system was raised to 80 °C in 4 h. 43% of benzene were removed in the first 2% of the extraction time. After 24 h, the repair efficiency was close to 100%. The device can efficiently remove benzene from soil. By continuously monitoring the parameters in the operation process of the system, the spatial distribution of temperature and soil gas pollutant concentration with time was plotted. It showed the benzene concentration distribution in the soil gas was more consistent with the temperature distribution before the start of ventilation, and the concentration of benzene in the soil gas dropped rapidly after ventilation, while the temperature distribution was almost unaffected. In the treatment of soil with a benzene content of 17.8 mg∙kg−1, when the soil gas benzene concentration is the highest at 180 min, the peak value is 11,200 mg∙m−3, and the average concentration is 7629.4 mg∙m−3.

scholarly journals Short Onset and Enhanced Analgesia Following Nasal Administration of Non-Controlled Drugs in Nanovesicular Systems

Pharmaceutics ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 978
Author(s):  
Elka Touitou ◽  
Hiba Natsheh ◽  
Shatha Boukeileh ◽  
Rania Awad
Keyword(s):  
Lipid Bilayers ◽  
Analgesic Effect ◽  
Drug Level ◽  
Nasal Delivery ◽  
Nasal Administration ◽  
Mice Model ◽  
Noninvasive Treatment ◽  
New Approach ◽  
Controlled Drugs ◽  
Peak Value

Nasal nanovesicular delivery systems (NVS) containing the noncontrolled analgesic drugs Ketoprofen, Butorphanol or Tramadol, incorporated in a phospholipid nanovesicular carrier, were designed and investigated. The systems were first characterized for their physicochemical properties. Due to their composition, comprising propylene glycol as a lipid bilayers fluidizer, these systems contain soft vesicles. Pharmacokinetic profiles of Tramadol in plasma and brain and of Ketoprofen in plasma were also assessed. The analgesic effect of each of the three tested drugs was evaluated in the acetic acid mice model for pain. One important result obtained in this work is that the concentration of Tramadol in rats’ plasma and brain increased rapidly after administration, reaching a peak value 10 min after administration with a Cmax of 2 to 5 folds greater than that for the oral or nasal non-vesicular treatments, respectively. In the case of Ketoprofen, the peak of the drug level in plasma was measured 10 min post nasal administration in NVS. The Cmax was three-fold higher relative to oral administration of this drug. In the experiment testing analgesia, a rapid and improved analgesia was observed for the tested drugs when delivered nasally in the nanocarrier. On the other hand, a weaker analgesic effect was observed for oral and nasal control systems. This new approach suggests that nasal delivery of non-controlled drugs in soft nanovesicles may open the way for better and noninvasive treatment of severe pain.

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