Introduction: Worldwide coronavirus created is a major problem for human health, food security, economy and many more. World Health Organisation (WHO) named this virus COVID-19. This virus is first detected in Wuhan, China in December 2019 and after that, it’ s spreading over the world. Lockdown is healing the environmental condition because major Indian metropolitan cities are recovered from different pollutants. This study is to identify the air quality trend before, during and after the lockdown in Siliguri city, the third-largest city of West Bengal and this city is also a commercial and transportation hub. Materials and methods: The air quality data have been derived from West Bengal Pollution Control Board (WBPCB) and proceed in MS-Office and ArcGIS 10. 4. The air pollutant and week air quality data have been used for monitoring the environmental situation. Results: In this study, results show that around 70%-90% of air quality is increased during strict lockdown but again air quality is decreased after lockdown gradually. The weekly air quality graph significantly changes during lockdown but after lockdown, the graph was increased. The highest air quality shows 347 before lockdown but during lockdown it’ s decreased 25 on 23-24 May 2020. After lockdown public transport, industrial area and small scale industries are reopened and again the air quality increased. The highest air quality shows 353 on 14 January 2021 during unlock 8. 0. Conclusion: This pandemic taught how anthropogenic activates, like urbanization, population pressure and industrial works were endangering the environment and some caution is essential for future livelihood.

In this article, an attempt has been made to estimate the amount of sound transmission loss in a flat oval channel by applying the approach of Statistical energy analysis. Correct estimation of sound transmission loss in an air conditioning channel is of great importance due to the harmful effects of noise pollution in the environment on human health. Simulation with the Statistical energy analysis method is a powerful approach to estimate sound and vibration in problems in which we deal with complex and multi-part systems; is considered. In this method, first, a system is divided into several subsystems, and then by writing a matrix equation that includes the energy exchanges between subsystems and energy loss coefficients; It is investigated from the perspective of vibration and sound estimation.On average, the model presented in this research is able to estimate the sound transmission loss in different dimensions of the air conditioning channels according to the experimental results in the accuracy range of ± 2.5 dB. Considering that it seems that the results obtained from modeling with this method are in good agreement with the experimental data; The results of this research can be used as an efficient approach to estimate noise in oval shaped channels stretched in different lengths.

The purpose of this study is to identify the effect of stock tendency to deal with fluctuations and price fluctuation thresholds in creating fluctuations. The Statistical population of the present study is the companies listed on the Tehran Stock Exchange that were present in the stock exchange during the years 2005 to 2018. In order to confirm and reject the research hypothesis, Eviews software has been used. In Tehran Stock Exchange, following severe stock price fluctuations, the stock price fluctuation mechanism is used to limit severe stock price fluctuations, and according to certain periods, the range of stock price fluctuations changes and over time the range of fluctuations increases. The basis of trial and error has been determined and in a short period of time there have been many changes in the procedures related to the application of stock price fluctuations, without really measuring the impact of these decisions in the market and investors' reaction to changes in price fluctuations. Findings showed that the number of times each share hits the price fluctuation Yield fluctuation has a significant effect.slow efficiency fluctuations have a significant effect; And in line with the concepts of hyper-reactive theory, it can be justified, that is, after the price reaches the range of fluctuation, the trend reverses and the basis of the fluctuation limit changes; It has changed the volatility of stock returns based on jump and price continuity.

Water stress considers as most important I environmental stresses. The effect of water stress in secondary metabolite fluctuation of Hypericum perforatum (hypericin) evaluated with performance of well water, mild and severs water stress treatments in Karaj research station. In this experiment a CRBD with 3 replications in 3 years was used. Well water (-0.3 bar), mild water stress (-3 bar) and sever water stress (-15bar) treatments according 17.4, 11.5 and 8.5 water weight percent relative to dry soil were performed respectively. Hypericin extracted in two stages by soxhelt (using CHCL3 and MeOH) and measured by UV spectrophotometer in 590 nm. The results showed that top yield, hypericin percentage and hypericin yield increased with well water. Mild and sever water stress caused to decreasing hypericin and yield of Hypericum perforatum. Top yield and hypericin amount in the first harvest was 2-3 folds to the second harvest. Correlation between hypericin amount and flowers per plant was significant and positive. In spite of Hypericum perforatum resistance to water stress, it produced lower tops and hypericin under water stress. Adequate and on time irrigation causes to completely growth and more flower which increases quality in H.perforatum.

Elevated intraocular pressure (IOP) is a major risk factor for the development and progression of glaucoma. Previous prospective, randomized, long‑ term studies have demonstrated the strength of IOP reduction in slowing the progression of disease. It is well known that IOP is not a fixed value but fluctuates considerably over time. Although there have been some studies on IOP fluctuation and the progression of glaucoma, whether IOP fluctuation is an independent risk factor for glaucomatous damage and disease progression remains controversial. In this article, we reviewed the definition of IOP fluctuation, and both the evidence and the speculation for and against the effect of IOP fluctuation on glaucoma progression. Although conclusions seem to vary from study to study, we considered that different studies examined different groups of patients, at different stages of disease, and at different IOP levels. Our conclusion is that these apparently disparate results are not conflicting, but rather can be viewed as complementary. In clinical care, we recommend the consideration of IOP “ modulation” rather than just IOP “ reduction” when glaucoma patients are treated. Quality‑ based IOP control may be more effective than quantity‑ based IOP reduction to prevent or retard disease progression.

The anomalous behavior of angular distribution of fission fragments reported by different authors during last years. We can explain some part of these anomalous behavior by TSM, also associated it on large value spins of targets or projectiles or the fissionability parameter (Z2/ A) of compound nucleus. For large value of anisotropy, the SSM is more useful and the parameter S02, is obtained by best fitting the analytical relation to experimental data. In this research work the SSM is employed for explaining the anisotropies of these reactions 10B(64Mev)+237Np , 10B(60Mev)+232Th" 12C(72Mev)+237Np , 12 C(79Mev)+232Th " 160(88Mev)+232Th 16 O(94Mev)+237Np. And we have show that we can explain the angular distribution of fission fragments by SSM when at least the spins of projectile or target is nonzero at moderate energies, Also the ratio of spherical moment of inertia to effective moment of transition nucleus is calculated by this model.

Geometry of the chute blocks in stilling basins plays a significant role in size and type of these structures. One of the most influencing factors in the design of the blocks is the fluctuating pressure which may cause fatigue on the blocks. Despite investigations conducted by many researchers, there is not enough information about the pressure fluctuation around chute blocks in compacted stilling basins such as Saint Anthony Falls (SAF) basins. In this paper, the results of a naval experimental work and measurement of pressure fluctuations around chute blocks of SAF stilling basins are reported. The results show that the pressure fluctuations around the chute blocks cannot be overlooked in designing such structures. The variation of pressure fluctuation with Froude number of incoming supercritical flow at various faces of the chute block is reported, which shows an increasing trend of pressure fluctuation. It is also observed that the submergence of hydraulic jump will decreasingly affect the pressure fluctuations. The trend of variations will follow different patterns at the different faces of the block.