Markov chain model probability of dry, wet of rainy wet weeks during moonson period over Andhra Pradesh

For agricultural planning, it is important to know the sequence of dry, wet periods. For this purpose a week period may be taken as the optimum length of time. The success or failure of crops particularly under rainfed conditions is closely linked with the rainfall patterns. In this study the Markov chain model method has been applied to know the probability of having a dry or a wet week and consecutive dry or wet periods of 2 or 3 weeks during monsoon period over Andhra Pradesh.

T-Shaped Control Plate Effect on Flow past a Square Cylinder at Low Reynolds Numbers

In this study, the influence of the T-shaped control plate on the fluid flow characteristics around a square cylinder for a low Reynolds numbers flow is systematically presented. The introduction of upstream attached T-shaped control plate is novel of its kind as T-shaped control plate used for the first time rather than the other passive control methods available in the literature. The Reynolds numbers (Re) are chosen to be Re = 100, 150, 200, and 250, and the T-shaped control plate of the same width with varying length is considered. A numerical investigation is performed using the single-relaxation-time lattice Boltzmann method. The numerical results reveal that there exists an optimum length of T-shaped control plate for reducing fluid forces. This optimum length was found to be 0.5 for Re = 100, 150, and 200 and 2 for Re = 250. At this optimum length, the fluctuating drag forces acting on the cylinder are reduced by 134%, 1375, 133%, and 136% for Re = 100, 150, 200, and 250, respectively. Instantaneous and time-averaged flow fields were also presented for some selected cases in order to identify the three different flow regimes around T-shaped control plate and square cylinder system.

Stock Assessment of Exploited Sardine Populations from Northeastern Bay of Bengal Water, Bangladesh Using the Length-Based Bayesian Biomass (LBB) Method

Stock assessment is necessary to understand the status of fishery stocks. However, for the data-poor fishery, it is very challenging to assess the stock status. The length-based Bayesian biomass (LBB) technique is one of the most powerful methods to assess the data-poor fisheries resources that need simple length frequency (LF) data. Addressing the present gap, this study aimed to assess the stock status of three sardines (Sardinella fimbriata, Dussumieria acuta, and D. elopsoides) in the Bay of Bengal (BoB), Bangladesh using the LBB method. The estimated relative biomass for S. fimbriata was B/B0 < BMSY/B0, indicating the overfished biomass, while the assessed B/B0 > BMSY/B0 for D. acuta and D. elopsoides indicates healthy biomass. Additionally, for S. fimbriata, the length at first landing was smaller than the optimum length at first landing (Lc < Lc_opt), indicating an overfishing status, but a safe fishing status was assessed for D. acuta and D. elopsoides (Lc > Lc_opt). Therefore, increasing the mesh size of fishing gears may help to ensure the long-term viability of sardine populations in the BoB, Bangladesh.

Analysis of Stock Price Data: Determinition of The Optimal Sliding-Window Length

Over the recent years, the study of time series visualization has attracted great interests. Numerous scholars spare their great efforts to analyze the time series using complex network technology with the intention to carry out information mining. While Visibility Graph and corresponding spin-off technologies are widely adopted. In this paper, we try to apply a couple of models derived from basic Visibility Graph to construct complex networks on one-dimension or multi-dimension stock price time series. As indicated by the results of intensive simulation, we can predict the optimum window length for certain time series for the network construction. This optimum window length is long enough to the majority of stock price SVG whose data length is 1-year. The optimum length is 70% of the length of stock price data series.

Stock Assessment of 19 Perciformes in the Beibu Gulf, China, Using a Length-Based Bayesian Biomass Method

The Beibu Gulf in China is rich in fish resources. However, only a small number of commercially developed fish stocks have been specifically assessed owing to limited data and expertise. In this study, 19 perciform fish populations in the Beibu Gulf were assessed using a length-based Bayesian biomass (LBB) estimator method, which is a new approach to evaluate a fishery’s status using length frequency (LF) data. The results showed that only 21% of the evaluated stocks were healthy and 79% were overfished. In particular, 26 and 21% of the assessed species had collapsed and were grossly overfished, respectively. Only 11 and 21% of the assessed species were slightly overfished and overfished, respectively. The ratios between the mean and optimum length (Lmean/Lopt) and between the mean length at first capture and the mean length, which maximizes catch and biomass (Lc/Lc_opt), were below one in 14 out of the 19 stocks, suggesting a truncated length structure and fishing of undersized individuals. The ratio of the 95th percentile length to asymptotic length L95th/Linf was close to one (&gt;0.9) in 10 of 19 stocks, suggesting that at least some large fish were still present. Our research confirmed that the fishery resources in the Beibu Gulf were seriously overfished and provided evidence that LBB was an efficient method to evaluate the fishery resources. Fishery managers need to take specific measures to restore fishery resources.

Population dynamics of Chrysichthys nigrodigitatus (Lacépède, 1803) in Ikere-gorge, Oyo State, Nigeria

The growth and mortality parameters of Chrysichthys nigrodigitatus were estimated to assess the sustainability of its exploitation in Ikere-gorge, Oyo State, Nigeria. A total of 1210 of Chrys­ichthys nigrodigitatus were sampled from fishermen catches between January, 2017 and Decem­ber, 2018. C. nigrodigitatus were exploited with gillnet, cast net and traps (Malian trap net and bamboo). Total lengths were measured with fish measuring board. The FAO-ICLARM Stock Assessment Tool (FiSAT II) software was used to analyze length-frequency data of the fish. The estimated growth parameters are: asymptotic length is 60.9 cm, growth coefficient is 0.96, optimum length is 38.51 cm; length at maturity is 33.44 cm while length-at-first-capture is 12.62 cm. The estimated mortality parameters are: total mortality is 3.29 per year, natural mortality is 1.43 per year and fishing mortality is 1.86. It was observed that C. nigrodigitatus of Ikere-gorge were more vulnerable to exploitation at sizes less than their length at maturity. Likewise, the ex­ploitation rate (E = 0.57 yr-1) is greater than sustainable exploitation rate (Emax = 0.46 yr-1). This shows that exploitation of C. nigrodigitatus in Ikere-gorge is not sustainable. Therefore, there is need to reduce fishing pressure on C. nigrodigitatus to ensure its sustainability in Ikere-gorge.

Effect of an axial-radial plate reactor modifications on a mega methanol plant production

Axial-radial flow plate reactors have been recently considered as efficient and practical types of reactors for methanol synthesis. Generally, an axial–radial reactor (AR) consists of two main parts namely the axial section and the radial section and the vast majority of the feed enters the radial section. Moreover, the structure of AR has a space above the axial part, which can add an adiabatic bed in the system. In this study, the performance of two novels AR configurations is investigated to improve the effectiveness of the axial–radial plate reactor. In the first configuration, the optimum length of the adiabatic bed is calculated and the adiabatic bed is located above the axial section inside the AR and is named IAAR. Therefore, in IAAR the feed of the axial section just enters the adiabatic bed and warms up. On the other configuration, the adiabatic bed with the optimum length is placed outside the reactor and is named OAAR. Therefore, in OAAR the total feed passes through the adiabatic bed, highly warms up, then cools to the optimum temperature in a heat exchanger, and finally enters AR. Two-dimensional mathematical modeling via orthogonal collocation on the finite element method is developed to compare the performance of two configurations. The results show that the maximum proportion of methanol produces in IAAR, which is approximately 3.8% higher than that produced in conventional AR due to utilizing an adiabatic bed inside the AR and superior gas distribution in the process. Momentum, mass, and heat equations are calculated and molar flow rates, mole fractions and temperatures are depicted along the radius and the length of the three configurations.

Optimization of Test Procedure for Simulation of Paper Laminate in Axial Loading Conditions Using FRANC2D and CASCA

In present investigation, an attempt was made to optimise the peak stress for paper laminate composite using FRANC2D software. It was observed that the laminate having the triangular geometry supposed to be most appropriate as it has the lowest value of peak stress contour compared to other models like parallel strip, up-down tapered and down-up tapered. The minimum peak stress was observed for the samples having triangular geometry while the maximum was observed for down-up tapered samples. Therefore, the hypothesis adopted to use in-built materials with variables reinforcement area and strip geometry and length in the FRANC2D software to optimize the sample geometry and then apply it to the paper laminate by considering its mechanical properties might be use to optimize the peak stress of paper laminate composite in tensile loading conditions. It was also observed a length of one-quarter of the length of the plane strip, might be the optimum length of the paper laminate samples. However, it feels that, the above model can be further modified considering a more significant mechanical properties as well as different sample geometries.

Wavelength division multiplexing developed with optimum length-based EDFA in the presence of dispersion-compensated fiber system

This work outlines 80-channel wavelength multiplexing that has been developed with optimum length-based erbium-doped fiber amplifier (EDFA) with dispersion-compensated fiber. This paper has presented different fiber mediums with different effective areas such as single mode fiber (SMF), highly nonlinear fiber (HNLF), highly nonlinear dispersion-flattened fiber (HNL-DFF), nonreturn to zero dispersion-shifted fiber (NRZDSF) and a two types of large effective area fiber (LEAF Step core and LEAF Ring core) with dispersion-compensated fiber and EDFA amplification. Optimum fiber length can be obtained using minimum and maximum bit error rates with channels number and bit rate variations.

Best selected optical fibers with wavelength multiplexing techniques for minimum bit error rates

In this study, six different types of optical fibers (SMF, HNLF, HNL-DFF, NZDSF, LEAF (step core) and LEAF (ring core)) can be used for different number of channels (16, 32, 64, and 80) at different bit rates to calculate the quality factor for these types of optical fibers at the optimum length for max BER × 10−9 and min BER × 10−12. By using the software Optisystem version 13, the work has been demonstrated and compared with previous study to find the best one under the same operating conditions.