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This article introduces a mesh-based magnetic equivalent circuit (MEC) modeling technique for induction machines (IMs) in healthy and broken rotor bars conditions. The MEC model is presented as a highly accurate and computationally efficient alternative to finite element (FE) models. By incorporating modifications to the air gap coupling method, including a new Lagrange interpolation function, and utilizing a harmonic MEC model, the accuracy of the solution is improved while reducing electrical and mechanical transients. Compared to experiments and 2-D FE models, this model achieves precise results for electromagnetic torque, rotational speed, and forces across various conditions. The Lagrange interpolation function forms the basis for the air gap coupling between stator and rotor flux densities. The results demonstrate the MEC model’s exceptional accuracy in predicting speed oscillations, calculating forces, and analyzing current harmonics in faulty IMs. Furthermore, the MEC model performs over 30 times faster than the 2-D FE models.

This article presents a novel data augmentation method that generates feature values for unmeasured loading levels based on limited measured and simulated loading level data. The incorporation of offline simulated data in the augmentation framework and the mapping of the error distribution over the loading levels greatly reduce the dependency on including a large number of loading levels in the curve fitting process. Furthermore, the proposed method shows high potential to minimize the deviation between measured and simulated data at the feature level. The method is applied to the induction machine (IM) to generate feature values at 25% and 50% loading levels for healthy, one, two, and three broken rotor bars (BRBs) conditions. An excellent agreement is observed between the augmented and actual feature values calculated from the measured data at 25% and 50% loading levels. The inclusion of this augmented data in the training phase aids in resolving the generalization issue and enhancing the average classification accuracy of the extreme gradient boosting (XGBoost) algorithm by 9.4% and 4.4% at 25% and 50% loading levels, respectively.

Most antimicrobial peptides (AMPs) induce pore formation and a burst of lipid bilayers and plasma membranes. This causes severe leakage of the internal contents and cell death. The AMP PGLa forms nanopores in giant unilamellar vesicles (GUVs) comprising dioleoylphosphatidylcholine (DOPC) and dioleoylphosphatidylglycerol (DOPG). We here elucidated the effect of the line tension of a prepore rim on PGLa-induced nanopore formation by investigating the interaction of PGLa with single GUVs comprising dioleoylphosphatidylethanolamine (DOPE)/DOPG (6:4) in buffer using the single GUV method. We found that PGLa forms nanopores in the GUV membrane, which evolved into a local burst and burst of GUVs. The rate of pore formation in DOPE/DOPG-GUVs was smaller than that in DOPC/DOPG-GUVs. PGLa is located only in the outer leaflet of a GUV bilayer just before a fluorescent probe AF647 leakage from the inside, indicating that this asymmetric distribution induces nanopore formation. PGLa-induced local burst and burst of GUVs were observed at 10 ms-time resolution. After nanopore formation started, dense particles and small vesicles appeared in the GUVs, followed by a decrease in the GUV diameter. The GUV was finally converted into smaller GUV or lipid membrane aggregates. We discuss the mechanisms of PGLa-induced nanopore formation and its direct evolution to a GUV burst.

ABSTRACTAmblypharyngodon molaHamilton 1822 is widely distributed in the freshwaters of Southeast Asia and is commercially important. We studied the size at sexual maturity (TL50) of A. molain addition to its fecundity indices using samples collected from the Ganges River, Bangladesh. A total of 1200 individuals of A. molawere examined comprising 373 males and 827 females. Based on the relationship between gonadosomatic index (GSI) and total length (TL), males with a GSI ≥ 2.31% and females with a GSI ≥ 4.66% could roughly be defined as mature. The TL50, the TL at which 50% of individuals become mature, was estimated by logistic equation as 5.85 cm in males and 5.97 cm in females. The total fecundity (FT) ranged from 1652 to 15,985 (6255 ± 3640). Both the studied variables (TL and body weight, BW) were highly correlated with FTand can be used to estimate the total potential fecundity, although BW performed better. Our results provide an insight into the TL50and reproductive potential of A. mola,which would be helpful to set the mesh-size restriction and to estimate potential recruitment and population growth rate for their sustainable management.

AbstractThe cyprinid pool barb Puntius sophore(Hamilton 1822) is widely distributed in freshwaters of Southern Asia. We determined some basic population biology parameters of P. sophoreincluding sex ratio, length-frequency distributions (LFDs), length-weight relationships (LWRs), condition factors, relative weight and fecundity. Samples were collected monthly during July 2010 to June 2011 from the Padma River, Bangladesh. The overall fish sex ratio significantly differed from the anticipated value of 1:1 (p< 0.001) in favour of female specimens (1: 1.31). Females were significantly larger and heavier than males (p< 0.001). The LWRs showed isometric growth in both sexes; however, with clear monthly variation. Fulton's condition factor was found to be significantly correlated with the total length (TL) and body weight (BW) and the most suitable among the studied condition factors for interpreting population well-being. Total fecundity varied from 1488 to 18708 (5682 ± 3703), while the relative fecundity from 205 to 1868 (882.7 ± 369.5). The total fecundity was found to be significantly related with TL, BW, ovary weight, gonadosomatic index and Fulton's condition factor. The determination of population biology parameters including fecundity will deepen understanding of the overall condition of P. sophorepopulations and their regenerative capacities.

Dengue fever is a viral infection caused by Aedesmosquitoes that has recently expanded fast in many of the WHO member states globally. Female mosquitoes, mostly Aedes aegyptiand, to a smaller degree, Aedes albopictus, disseminate dengue virus. Dengue fever has been more common in recent decades all across the world, and Bangladesh is no exception. As the COVID-19 outbreak wreaks havoc, the following rise in dengue illnesses has been a source of considerable concern. As the health care has been stretched thin in these dangerous times, the vulnerable population has been left at the mercy of these two viral infections. Lack of knowledge, major legislative changes, poor eradication initiatives, and a lack of financing resources have all contributed to the increase in numbers. Stakeholders and policymakers must begin taking meaningful actions and implementing well-thought-out adjustments immediately, or the situation will worsen, resulting in the loss of thousands of innocent lives.

A coupled one-component mathematical model is applied to analyze the transient natural convective hydro-thermal incidents of different nanofluids occupied with a quarter circular vicinity. A sinusoidal magnetic arena is preferred in the transverse direction to examine the magnetization phenomena. The circular arc of the geometry domain is cold and the lowest wall is heated whereas the vertical wall of the arena is kept thermally insulated. During numerical computation, herein considered Water (H2O), Kerosene (Ke), Engine Oil (EO) as base fluids and Copper (Cu), Cobalt (Co), and Iron Oxide (Fe3O4) as nanoparticles. The dimensionless transports equations are solved numerically by applying the Galerkin weighted residual based finite element method. The outcomes spectacle that heat transfer rate augmented significantly with the increasing values of the Rayleigh number (Ra), nanoparticles volume fraction (ϕ), and period of the magnetic field (λ), whereas an intensification in the Hartmann number (Ha) lessens the total heat transfer rate. For nine sorts of nanofluids, the average heat transfer rate is computed along the bottom wall, and found that the heat transfer rate of Co-Kerosene nanofluid is considerably greater than other eight sorts of nanofluids. Finally, it is observed that the Cu-Kerosene nanofluid provides the high heat transfer rate whereas Cu-EO has the low rate of heat transfer for distinct thermal boundary conditions. The numerical results could be useful in assessing heat transfer features of solar collectors, and electronic devices.

AbstractSaltmarsh and seagrass communities are coastal macrophytes. These communities perform a number of important ecological functions, one of which is to support substantial fishery resources either as a nursery ground or a refuge from predators. The Bangladesh coast houses saltmarsh and seagrass resources but there has been sparse information on the diversity of fisheries adjacent to these plant communities. Consequently, this study was carried out to obtain information on the shoot density and biomass of the dominant saltmarsh (Porteresia coarctata) and seagrass (Halophila beccarii) species together with the diversity of fisheries adjacent to saltmarsh and seagrass beds on the south eastern coast of Bangladesh. The below-ground biomass of P. coarctatawas found to be significantly higher than the above-ground biomass, presumably so as to survive under harsh environmental conditions, for example strong wave exposure. The standing crops and shoot density of the seagrass H. beccariishowed a similar pattern to that of the same seagrass species observed elsewhere. Overall, 5356 individuals of the faunal population comprising 38 species (21 families) of fish, 8 species (3 families) of shrimps and 2 species (2 families) of crabs were recorded. The similarity percentage analysis showed that Thryssa dussumieri(24.77% contribution) and Exopalaemon stylifer(9.52% contribution) were the most dominant species. Probably, these species utilize saltmarsh seagrass beds as nursery and feeding grounds more than other species.

AbstractThis baseline study was carried out to investigate the physicochemical factors such as pH, salinity, temperature, turbidity, total dissolved solids (TDS), total suspended solids and dissolved oxygen (DO), as well as nutrient (nitrate, phosphate, ammonium) concentrations and the level of heavy metals (Fe, Zn, Cu, Mn) in the surface water of the Miri estuary at four sampling times based on the four seasons of Malaysia. Results indicated marked temporal differences in each of the water characteristics measured (except ammonium), where DO level (mean: 3.6 mg/L) was found in a concern level. The principle component analysis (PCA) was applied to the hydrological and hydrochemical data set of the Miri estuary; results indicated that principle component 1 and principle component 2 explained 61.78 and 18.69%, respectively, of the total variance in the data set. Besides, results of PCA also indicated that the factors for water characteristics variations were mainly related to TDS, salinity, and Fe. The data presented here will serve as benchmark information, especially to the agencies related to the formulation of suitable policy on water quality in such areas.

Trace metals from industrial effluents discharged into Malaysian mangrove ecosystems, in Sarawak in particular, are of growing concern. Concentrations of trace metals (copper, manganese, iron, and zinc) were determined in sediment, surface water, pore water, green and red filamentous macroalgae (Chaetomorphasp. and Bostrychiasp., respectively) and the rock oyster Saccostrea cucullatafrom three estuarine mangrove habitats in Sarawak (Kuala Nyalau, Bakam, and Miri), Malaysia. Trace metal concentrations detected in sediment of these mangrove ecosystems (except for Zn concentration in K. Nyalau) were considerably higher than those specified in USEPA sediment quality guidelines. Sediment trace metal concentrations differed significantly (p < 0.05) among the stations studied. In pore water, trace metal concentrations were found to be higher than those in estuarine surface water. The order of trace metal concentrations in Chaetomorphasp., Bostrychiasp. and S. cucullatawas Fe > Mn > Zn > Cu, Fe > Zn > Mn > Cu, and Fe > Mn > Zn > Cu, respectively. Bioconcentration factors (BCFs) in macroalgae and in one oyster species were inconsistent, although BCFs were much higher in water than in sediment. In sediment, the BCF of Mn was the highest among trace metals in S. cucullata, followed by Cu and Zn. BCF of iron (Fe) was relatively low in spite of its high concentration in sediment and water. The findings of this study may prove helpful in carrying out future studies aimed at detecting a potential biomarker in coastal ecosystems of Sarawak, Malaysia.

Bangladesh, a low-middle-income country in South Asia is facing one of its worst public health emergencies due to the COVID-19 pandemic. The increase in the number of cases from the disease, since the second half of March 2021, can potentially cause the health system overload, and has, as one of the main reasons, the non-compliance with measures of social distance and the emergence of the variants of concern in the country. This increase in the contagion curve can also provide a favorable environment for the occurrence of more mutations in the structure and genome of the virus. Therefore, there is an urge to carry out genomic surveillance programs in order to identify, monitor and characterize these variants, and understand whether the vaccines currently used are effective against them.

A flexible snake robot has better navigation ability compare with the existing electrical motor-based rigid snake robot, due to its excellent bending capability during navigation inside a narrow maze. This paper discusses the modelling, simulation and experiment of a flexible snake robot. The modelling consists of the kinematic analysis and the dynamic analysis of the snake robot. A platform based on the Incompletely Restrained Positioning Mechanism (IRPM) is proposed, which uses the external force provided by a compliant flexible beam in each of the actuators. The compliant central column allows the configuration to achieve three degrees of freedom (3DOFs) with three tendons. The proposed flexible snake robot has been built using smart material, such as electroactive polymers (EAPs), which can be activated by applying power to it. Finally, the physical prototype of the snake robot has been built. An experiment has been performed in order to justify the proposed model.