Latest Research on Wave Characteristic: Dec 2020

Wave characteristic analysis and wave energy resource evaluation in the China Sea

This study presents the characteristics of the China Sea wave energy resource and wave climate for the period August 1999 to July 2009, using a 10-yr hindcast wave data obtained from WAVEWATCH-III (WW3) numerical wave model forced with QuikSCAT/NCEP (QN) wind data. Results show that: (1) The China Sea wave field has significant seasonal differences, especially the South China Sea which is obviously affected by the monsoon. In JJA (June, July, August), the dominant wave direction is south to southwest. In DJF (December, January, February), the dominant wave direction is north to northeast. The Luzon Strait is the relative large center of significant wave height in DJF (2.4–2.8 m), SON (September, October, November) (2.0–2.4 m), and MAM (March, April, May) (1.0–1.4 m), while the southeast area of the Indo-China Peninsula is the large center in JJA (1.2–1.6 m). (2) The rough sea occurrence in the China Sea is relative low, of below 14% in each season. The relative high occurrence happened in DJF, followed by the SON, lowest in MAM. (3) The extreme wave height with return period of 20 yr in the Bohai Sea, Yellow Sea, low latitude of the South China Sea is below 8 m. The large areas mainly distribute in the middle latitude. The distribution of extreme wave height with return period of 30 yr is similar and about 2 m larger than that with return period of 20 yr. (4) We find the China Sea wave power increases gradually from MAM to DJF. The Luzon Strait is the relative large region of wave power in DJF (30–40 kW/m), SON (21–27 kW/m), and MAM (6–10 kW/m), while the southeast area of the Indo-China Peninsula is the large center in JJA (6–11 kW/m). (5) The stability of the China Sea wave power exhibits obvious regional and seasonal differences. The wave power is the most stable in DJF. The wave power in the north area of the South China and East Sea is apparently more stable than that in other sea areas, in the offshore is more stable than that in the near shore. (6) Judging from the value and stability of wave power, we find that the relative rich-energy region locates in the Luzon Strait and adjacent waters in DJF, SON, and MAM, while in the southeast area of the Indo-China Peninsula in JJA. [1]

Hygrothermal wave characteristic of nanobeam-type inhomogeneous materials with porosity under magnetic field

Flexural and longitudinal wave behaviors of nanobeams made of nanoporous-graded materials while surrounded by Winkler-Pasternak foundation, subjected to the longitudinal magnetic field and exposed to the hygrothermal environment are studied analytically. To this end, the governing equation derived by Euler–Bernoulli beam theory in conjunction with the nonlocal strain gradient theory is defined by employing Hamilton’s principle. By adopting an analytic model, the flexural and longitudinal dispersion relations between phase velocity and wave number are derived. The reliability of the present method is confirmed by comparing the obtained results with those stored in the literature. Finally, the effects of the power-law index, porosity volume fraction, nonlocal and material characteristic parameters, uniform temperature and moisture rise, elastic foundation parameters, magnetic field intensity, and wave number are also investigated in detail. It is found that the small-scale parameters are more influential in higher wave numbers where the wavelength is close to the length scale of nanostructures. However, foundation parameters, porosity volume fraction, and longitudinal magnetic field are more influential in lower wave numbers. [2]

Entropy preserving low dissipative shock capturing with wave-characteristic based sensor for high-order methods

Shock capturing procedures are required to stabilise numerical simulations of gas dynamics problems featuring non-isentropic discontinuities. In the present work, particular attention is focused on the expected non-monotonicity of the entropy profile across shock waves. A peculiar physical property which was not considered so far in the evaluation of shock capturing techniques. In the context of high-order spectral difference methods and using most recent discontinuity sensors based on the decay rate of the modes of the amplitude of characteristic waves, results show how the choice of a physical-based procedure (additional viscosity) returns a better description of shocks compared to approaches relying on the direct addition of a Laplacian term in the solved equations. Various canonical compressible flows are simulated, in one-, two-, and three-dimensional setups, to illustrate the performance and flexibility of the proposed approach. It is shown that the addition of a well-calibrated bulk viscosity is capable of smoothing out discontinuities without an excessive damping of vortical structures, preserving also specific compressible flow physics, as the non-monotonic entropy profiles through the shocks. [3]

Quantitative Eradicative Cure Profile of HIV/AIDS Using Electromagnetic (EM) Wave Destruction Technique

It is the vibration of an unknown force that causes life and existence. Therefore, for anything to exist it must possess vibration. Vibration produces wave. It is the vibration of the HIV parasite (parasitic wave) that is being superposed on the Human Vibration (host wave) and since the waves are incoherent and out of phase the resultant superposition is destructive. Destructive interference causes a gradual attenuation in the general mechanism of the body system which eventually leads to a general loss of signal if uncontrolled. If the vibration of anything is known, then its characteristics can be predicted and be destroyed by an anti-vibrating component. In this work, we numerically calculated the wave characteristics of the Human vibration and that of the HIV vibration. In this paper, we show quantitatively how regulated dose of electromagnetic (EM) wave, can be used to eradicate HIV/AIDS condition from the Human system the resident host. The spectrum of the interception of the applied oscillating EM wave with the HIV vibration in the Human system shows a constriction in the interval when the raising multiplier [8000, 9000] with a corresponding time interval [1499.8125, 1499.8333] seconds. Therefore, the actual time of exposure of the HIV/AIDS patient who is undergoing the radiation therapy is about 0.0208 seconds. The displacement of the applied oscillating EM wave tends to zero within this interval. This study also shows that the time it would take the applied EM wave to destroy the HIV vibration completely from the human system is also determined by the phase angle between the applied oscillating EM wave and the HIV parasitic wave. [4]

Carotid-radial Pulse Wave form and Velocity in Normotensive and Hypertensive Pregnant Women at University Teaching Hospital (UTH), Lusaka, Zambia

Background: Hypertensive disease in pregnancy continues to be one of the leading causes of maternal death. Pregnancy induced hypertension (PIH) is said to be accompanied by several cardiovascular pathophysiological changes including increases in arterial stiffness. Pulse wave velocity (PWV) is a method for measuring arterial stiffness. Both the pulse wave form and the velocity are said to change in PIH. However, studies documenting these characteristics of the pulse wave have mainly been in the Caucasian population.

Aims and Objectives: To establish the characteristics of the carotid-radial (cr) pulse wave in normotensive (NTN) and hypertensive (HTN) pregnant black African women at the UTH in Lusaka, Zambia.

Methodology: This cross-sectional study comprised of 26 systemically selected pregnant women between the ages 18-45 years old who met the criteria. A structured interview was used to collect socio demographic data. Anthropometric measurements were taken. After a 15 minute rest, peripheral systolic and diastolic blood pressures (BP) were measured. The PWV measurement involved applying non-invasive piezoelectric sensors on the skin over the carotid artery in the neck and the radial artery on the wrist (carotid-radial segment crPWV). Using IBM® SPSS® version 20.0 analyses were made using mann – whitney and spearman correlation tests. A 95% confidence interval (CI) and P-value of <0.05 were set. Quality recordings were obtained from the crPWV recording processes showing the wave forms and specific measurements were made.

Results: The anthropometric measurements were comparable between the 2 groups. There were significant changes in the pulse wave forms. While the normotensive participants had the type C wave form, the type A wave form was recorded from hypertensive participants. The augmentation pressure (AP) in NTN was 4±5 mmHg while it was 9±8 mmHg in HTN, indicating an increase in pressure difference from the systolic shoulder to the peak of the pulse wave (p <0.05). There was also a significant increase in the augmentation index (Aix) (1±22% vs 16±23%) (p<0.05).             The hypertensive pregnant women also had a significantly higher PWV (9±4 m/s vs 13±7 m/s) (p<0.05).

Conclusion: Distinct differences were seen in the cr pulse wave forms and velocity between normotensive and hypertensive individuals with PIH indicating an increase in arterial stiffness. These findings suggest the presence of significant peripheral vascular changes that may underly the pathophysiology of PIH. [5]

Reference

[1] Zheng, C.W., Zhou, L., Jia, B.K., Pan, J. and Li, X., 2014. Wave characteristic analysis and wave energy resource evaluation in the China Sea. Journal of renewable and sustainable energy, 6(4), p.043101.

[2] Karami, B., Shahsavari, D., Karami, M. and Li, L., 2019. Hygrothermal wave characteristic of nanobeam-type inhomogeneous materials with porosity under magnetic field. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 233(6), pp.2149-2169.

[3] Tonicello, N., Lodato, G. and Vervisch, L., 2020. Entropy preserving low dissipative shock capturing with wave-characteristic based sensor for high-order methods. Computers & Fluids, 197, p.104357.

[4] Enaibe, E. A., Akpata, E., Nwose, E. U. and Judith, U. (2017) “Quantitative Eradicative Cure Profile of HIV/AIDS Using Electromagnetic (EM) Wave Destruction Technique”, Journal of Scientific Research and Reports, 13(3), pp. 1-28. doi: 10.9734/JSRR/2017/30870.

[5] Kaluba, L., Vwalika, B., Jere, M. and M. Goma, F. (2015) “Carotid-radial Pulse Wave form and Velocity in Normotensive and Hypertensive Pregnant Women at University Teaching Hospital (UTH), Lusaka, Zambia”, Cardiology and Angiology: An International Journal, 4(3), pp. 107-114. doi: 10.9734/CA/2015/19997.

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