The standard solid-state reaction method was employed to synthesize the polycrystalline Ca0.9Sr0.1Mn1−xMoxO3 (CSMMO with x = 0.00, 0.02, 0.04, 0.06, and 0.08) ceramics and each composition was sintered at 1300˚C for 4...The standard solid-state reaction method was employed to synthesize the polycrystalline Ca0.9Sr0.1Mn1−xMoxO3 (CSMMO with x = 0.00, 0.02, 0.04, 0.06, and 0.08) ceramics and each composition was sintered at 1300˚C for 4 hours. The crystal structure, microstructure, optical properties, electrical properties, complex initial permeability, and DC magnetization of the prepared compositions were carried out. The compound exhibited perovskite structure with the transformation of phase from orthorhombic symmetry for x = 0.00 to x = 0.04 samples into a tetragonal symmetry for the samples x = 0.06 and x = 0.08. The lattice constant was found to be enhanced with the doping of Mo concentration. The mean grain size was estimated in the micrometer, with values from 1.3045 to 3.0124 µm. Energy band gap (Eg) was determined for each composition and the magnitudes of Eg were lying between 1.85 - 4.00 eV. The Eg values firstly decreased with the doping content up to 2% and, then, increased for 4% to 6% Mo contents, where it again very slightly decreased for 8% Mo content. The lowest value of Eg was obtained for the x = 0.02 composition. The FTIR spectra revealed the existence of a metal oxide band in each of the prepared samples and supported the formation of a single-phase compound of synthesized material without any impurity, as confirmed by the XRD analysis. The electrical properties, such as resistivity and AC conductivity, were collected using the Impedance analyzer at room temperature. The resistivity and AC conductivity increased with the addition of dopant concentration. The frequency-dependent conductivity spectra showed three distinct regions. The complex initial permeability (μ′) was found to be enhanced with the addition of Mo and the highest value was noticed the 6% Mo dopant sample. On the other hand, the lowest loss factor was obtained for the samples x ≥ 0.06. The M-H hysteresis loops of various Ca0.9Sr0.1Mn1−xMoxO3 ceramics were measured both at room temperature (300 K) and low temperature (5 K). The values of saturation magnetization (Ms) and retentivity (Mr) were found to be larger at low temperatures than at room temperature (RT), although no saturation was obtained for any compositions. The highest saturation magnetization obtained at room temperature for the x = 0.06 sample was 0.8581 emu/g.展开更多
A study has been arranged to investigate the flow of non-Newtonian fluid in a vertical asymmetrical channel using peristalsis. The porous medium allows the electrically conductive fluid to flow in the channel, while a...A study has been arranged to investigate the flow of non-Newtonian fluid in a vertical asymmetrical channel using peristalsis. The porous medium allows the electrically conductive fluid to flow in the channel, while a uniform magnetic field is applied perpendicular to the flow direction. The analysis takes into account the combined influence of heat and mass transfer, including the effects of Soret and Dufour. The flow’s non-Newtonian behavior is characterized using a Casson rheological model. The fluid flow equations are examined within a wave frame of reference that has a wave velocity. The analytic solution is examined using long wavelengths and a small Reynolds number assumption. The stream function, temperature, concentration and heat transfer coefficient expressions are derived. The bvp4c function from MATLAB has been used to numerically solve the transformed equations. The flow characteristics have been analyzed using graphs to demonstrate the impacts of different parameters.展开更多
The fundamental frequency plays a significant part in understanding and perceiving the pitch of a sound. The pitch is a fundamental attribute employed in numerous speech-related works. For fundamental frequency extrac...The fundamental frequency plays a significant part in understanding and perceiving the pitch of a sound. The pitch is a fundamental attribute employed in numerous speech-related works. For fundamental frequency extraction, several algorithms have been developed which one to use relies on the signal’s characteristics and the surrounding noise. Thus, the algorithm’s noise resistance becomes more critical than ever for precise fundamental frequency estimation. Nonetheless, numerous state-of-the-art algorithms face struggles in achieving satisfying outcomes when confronted with speech recordings that are noisy with low signal-to-noise ratio (SNR) values. Also, most of the recent techniques utilize different frame lengths for pitch extraction. From this point of view, This research considers different frame lengths on male and female speech signals for fundamental frequency extraction. Also, analyze the frame length dependency on the speech signal analytically to understand which frame length is more suitable and effective for male and female speech signals specifically. For the validation of our idea, we have utilized the conventional autocorrelation function (ACF), and state-of-the-art method BaNa. This study puts out a potent idea that will work better for speech processing applications in noisy speech. From experimental results, the proposed idea represents which frame length is more appropriate for male and female speech signals in noisy environments.展开更多
The aim of the study was to investigate the factors affecting consumers’internet shopping behavior during the coronavirus disease(COVID-19)pandemic in Bangladesh.The study measured the influence of product factor,pri...The aim of the study was to investigate the factors affecting consumers’internet shopping behavior during the coronavirus disease(COVID-19)pandemic in Bangladesh.The study measured the influence of product factor,price factor,time saving factor,payment factor,security factor,administrative factor,and psychological factor on consumers’internet shopping behavior during the coronavirus disease(COVID-19)pandemic.The research collected data from May 10,2020 to June 10,2020 in personal interview by online survey method through a structured questionnaire with five-point Likert scales from 230 Bangladeshi online consumers.Non-probability sampling method was used.Data were analyzed using descriptive statistics analysis,reliability analysis,and multiple regression analysis.Results exhibited that all factors except price factor and security factor had a momentous and positive association with consumers’internet shopping behavior during the coronavirus disease(COVID-19)pandemic in Bangladesh.It has implications for e-marketing practicing firms regarding the real strategy of online shopping for Bangladeshi consumers during the coronavirus disease(COVID-19)pandemic in Bangladesh.展开更多
Palm fiber (PF) reinforced acrylonitrile butadiene styrene (ABS) composite matrix was prepared by employing Injection Moulding Machine (IMM). Palm fiber was collected from ten different trees of different age group fr...Palm fiber (PF) reinforced acrylonitrile butadiene styrene (ABS) composite matrix was prepared by employing Injection Moulding Machine (IMM). Palm fiber was collected from ten different trees of different age group from Comilla region in Bangladesh. Three sets of samples were prepared for three different wt% (5%, 10% and 20%) of fiber contents. The mechanical (tensile strength, flexural stress, micro hardness, Leeb’s rebound hardness) and physical (bulk density and water absorption) properties were measured. The observed result reveals that the tensile strength (TS) and flexural stress (FS) were decreased with increasing fiber contents in the PF-ABS composites except 10% fiber content.展开更多
An analysis of Thermophoresis effect on unsteady magneto-hydrodynamic free convection flow over an inclined porous plate with time dependent suction in presence of magnetic field with heat generation has been consider...An analysis of Thermophoresis effect on unsteady magneto-hydrodynamic free convection flow over an inclined porous plate with time dependent suction in presence of magnetic field with heat generation has been considered by employing Nachtsheim-Swigert shooting iteration technique along with sixth order Runge-Kutta integration scheme. Resulting non-dimensional velocity, temperature and concentration profiles are then presented graphically for different values of the parameters entering into the problem. Finally, the effects of the pertinent parameters on the skin-friction coefficient, the rate of heat transfer (Nusselt number) and wall deposition flux (Stanton number), which are of physical interest, are exhibited in tabular form.展开更多
The energy demand in Australia is increasing with the industrialization and rapid economic growth.This study analyzed the relationships among the economic growth,Foreign Direct Investment(FDI),trade openness,urbanizat...The energy demand in Australia is increasing with the industrialization and rapid economic growth.This study analyzed the relationships among the economic growth,Foreign Direct Investment(FDI),trade openness,urbanization,and energy usage in Australia based on the data from World Development Indicators(WDI)from 1972 to 2021.The results indicates that there is a cointegration among economic growth,FDI,trade openness,urbanization,and energy usage,which was traced through the autoregressivedistributed lag(ARDL).The Zivot-Andrews unit root test reveals that energy usage,economic growth,FDI,urbanization,and trade openness show significant structural breaks in 1993,1996,1982,2008,and 1994,respectively.The ARDL model shows that economic growth has a positive and significant effect on energy usage in the long-run(0.814)and short-run(0.809).Moreover,the results also show that FDI(0.028)and trade openness(0.043)have positive impacts on energy usage in the long-run.However,urbanization shows a negative and significant influence on energy usage in the long-run(–0.965).Then,the research demonstrates a unidirectional causation between energy usage and trade openness,with energy usage significantly causing trade openness.The current study endorses energy consumption policies and investment strategies for a paradigm shifting from a reliance on fossil fuels as the primary energy source to renewable energy sources.These findings have profound implications for sustainable energy usage.展开更多
The novel polycrystalline Bi<sub>0.85</sub>Gd<sub>0.15</sub>Cu<sub>x</sub>Fe<sub>1-x</sub>O<sub>3</sub> (x = 0, 0.025, 0.05, 0.075, 0.10) multiferroics are s...The novel polycrystalline Bi<sub>0.85</sub>Gd<sub>0.15</sub>Cu<sub>x</sub>Fe<sub>1-x</sub>O<sub>3</sub> (x = 0, 0.025, 0.05, 0.075, 0.10) multiferroics are synthesized by the usual solid-state reaction route. The synthesis of the desired phase has been verified by the X-ray Diffraction (XRD) patterns. With major structural phases, few traces of secondary phases of Bi<sub>2</sub>Fe<sub>4</sub>O<sub>9</sub> and Bi<sub>25</sub>FeO<sub>40</sub> appear for all the compositions. A discontinuous series of structural changes with varying compositions are observed for the doped samples. The bulk density (ρ<sub>B</sub>) increases with Cu content reaches the highest at x = 0.05 and then declines. The complex initial permeability and dielectric characterizations are performed by Wayne Kerr Impedance Analyzer. The x = 0.05 samples having maximum density exhibit the highest permeability (μ<sub>i</sub>’) implying a close relation between μ<sub>i</sub>’ and the density. The reduction of μ<sub>i</sub>’ at higher Cu concentration is due to the low density of the samples associated with the increased intragranular pores. The dielectric constant (ε’) is measured against frequency in the range 1 kHz - 10 MHz. It is perceived that ε’ falls with the rise in frequency up to 100 kHz. This dielectric dispersion is observed at a lower frequency as a result of interfacial polarization outlined by Maxwell-Wagner. The maximum ε’ is obtained for x = 0.025 composition. In the low-frequency range, the AC conductivity σ<sub>AC</sub> is practically independent of frequency and resembles the DC conductivity (σ<sub>DC</sub>). In the vicinity of high frequency recognized as the hopping region, σ<sub>AC</sub> rises since the conductive grains are more active at high frequencies. The co-doping with Gd and Cu in BiFeO<sub>3</sub> ceramics enhances the magnetic and dielectric properties of the ceramics and hence can be utilized for fabricating multifunctional devices.展开更多
A study on the detection of probable radionuclides and their activity concentrations in the raw material (phosphate rock), final product (fertilizer) and waste samples collected from all the phosphate fertilizer facto...A study on the detection of probable radionuclides and their activity concentrations in the raw material (phosphate rock), final product (fertilizer) and waste samples collected from all the phosphate fertilizer factories (total two factories—A Diammonium Phosphate, DAP and a Triple Super Phosphate, TSP factory) in Bangladesh were carried out. A total of seven types of samples (grossly divided into solid and liquid types);liquid waste, waste-mixed river water, normal river water, phosphate rock, phosphate fertilizer, solid waste and normal soil;were analyzed under this study. Raw material samples were collected only from the TSP fertilizer factory. Fertilizer, solid and liquid waste samples were collected from both the factories under study. Moreover, normal soil and natural surface water samples from the suitable areas adjacent to the factories were also collected for the comparison purpose. The samples were analyzed by gamma ray spectrometry technique using a Hyper-Pure Germanium (HPGe) detector of 40% relative efficiency. The analysis of the samples showed that only natural radionuclides such as 226Ra, 232Th and 40K were present in the samples and no traces of artificial radioactivity were found in any of the samples. 40K was found below the detection limit in some samples. The analysis of the samples in the case of TSP fertilizer factory showed that the average activity concentrations of 226Ra and 232Th and 40K in raw materials were 851.27 ± 7.10, 19.63 ± 6.57 and 54.06 ± 5.93 Bq/kg, respectively, in final product 211.90 ± 4.74, 42.48 ± 10.56 Bq/kg and ND (Not Detected), respectively, in solid waste 187.49 ± 4.88, 70.06 ± 11.76 and 289.27 ± 40.24 Bq/kg, respectively and in liquid waste 6.26 ± 0.63, 10.01 ± 1.39 Bq/L and ND, respectively. The measured results in the case of samples collected from DAP fertilizer factory showed that the average activity concentrations of 226Ra and 232Th and 40K in the final product were 17.31 ± 3.92, 69.74 ± 9.88 and 48.46 ± 17.22 Bq/kg, respectively, in solid waste 24.47 ± 4.15, 164.62 ± 11.08, 191.52 ± 33.74 Bq/kg, respectively and in liquid waste 3.59 ± 1.05, 37.08 ± 3.30 Bq/L and ND, respectively. Considering the stored raw materials and wastes the part of the ambient environment of the factory, radium equivalent activity, radiation hazard index and external annual effective dose to the workers and public due to these materials were also calculated and compared with world average values.展开更多
Zinc Sulfide (ZnS) thin film has attracted increasing attention due to their potential applications in the new generation of nano-electronics and opto-electronics devices. The physical and chemical properties of ZnS h...Zinc Sulfide (ZnS) thin film has attracted increasing attention due to their potential applications in the new generation of nano-electronics and opto-electronics devices. The physical and chemical properties of ZnS have outstanding quality for different applications. Moreover, ZnS doped with various elements are creating a new era for both academic research and industrial applications. So, the optical properties of modified ZnS thin film will help us to find a suitable doping element for convenient deposition which may enhance the conductance and transmitting properties of the film. This review work has been carried out to explore the four-modification elements that constitute Cu, Ni, Co & Fe as descending order of atomic number corresponding to Zn, along with some potential applications considering the recent research work with other doping elements too such as Al, C, Pt etc. For example, FE, FET, Catalytic, Solar cell, Electroluminescence, Fuel cell, different sensors (Chemical sensors, Bio-sensors, Humidity sensors, light sensors, UV light sensors) and nanogenerators use ZnS thin film.展开更多
With the aid of Injection Moulding Machine (IMM) Palm fiber reinforced Acrylonitrile Butadiene Styrene (ABS) composites (PF-ABS) were prepared. Three sets of samples were prepared for three different wt% (5%, 10% and ...With the aid of Injection Moulding Machine (IMM) Palm fiber reinforced Acrylonitrile Butadiene Styrene (ABS) composites (PF-ABS) were prepared. Three sets of samples were prepared for three different wt% (5%, 10% and 20%) of fiber contents. Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) experiments were performed to study the surface morphology, microstructure (if it crystalline or noncrystalline) and new bond formation after preparation of the composites. SEM pattern shows that after addition of palm fiber in PF-ABS composites the brittleness increased due to creation of voids in the composites except 10% fiber content in PF-ABS. From XRD pattern it is clear that the palm fiber, ABS and PF-ABS composites are amorphous in nature. Moreover FTIR spectrum shows that there is no new bond formed after addition of palm fiber in ABS polymeric matrix to create PF-ABS composites.展开更多
We introduce a new integral scheme namely improved Kudryashov method for solving any nonlinear fractional differential model.Specifically,we apply the approach to the nonlinear space-time fractional model leading the ...We introduce a new integral scheme namely improved Kudryashov method for solving any nonlinear fractional differential model.Specifically,we apply the approach to the nonlinear space-time fractional model leading the wave to spread in electrical transmission lines(s-tfETL),the time fractional complex Schrödinger(tfcS),and the space-time M-fractional Schrödinger-Hirota(s-tM-fSH)models to verify the effectiveness of the proposed approach.The implementing of the introduced new technique based on the models provides us with periodic envelope,exponentially changeable soliton envelope,rational rogue wave,periodic rogue wave,combo periodic-soliton,and combo rational-soliton solutions,which are much interesting phenomena in nonlinear sciences.Thus the results disclose that the proposed technique is very effective and straight-forward,and such solutions of the models are much more fruitful than those from the generalized Kudryashov and the modified Kudryashov methods.展开更多
Pocket Switched Networks(PSN)represent a particular remittent network for direct communication between the handheld mobile devices.Compared to traditional networks,there is no stable topology structure for PSN where t...Pocket Switched Networks(PSN)represent a particular remittent network for direct communication between the handheld mobile devices.Compared to traditional networks,there is no stable topology structure for PSN where the nodes observe the mobility model of human society.It is a kind of Delay Tolerant Networks(DTNs)that gives a description to circulate information among the network nodes by the way of taking the benefit of transferring nodes from one area to another.Considering its inception,there are several schemes for message routing in the infrastructure-less environment in which human mobility is only the best manner to exchange information.For routing messages,PSN uses different techniques such asDistributed Expectation-Based Spatio-Temporal(DEBT)Epidemic(DEBTE),DEBT Cluster(DEBTC),and DEBT Tree(DEBTT).Understanding on how the network environment is affected for these routing strategies are the main motivation of this research.In this paper,we have investigated the impact of network nodes,the message copies per transmission,and the overall carrying out of these routing protocols.ONE simulator was used to analyze those techniques on the basis of delivery,overhead,and latency.The result of this task demonstrates that for a particular simulation setting,DEBTE is the best PSN routing technique among all,against DEBTC and DEBTT.展开更多
In this work, the Micropolar fluid flow and heat and mass transfer past a horizontal nonlinear stretching sheet through porous medium is studied including the Soret-Dufour effect in the presence of suction. A uniform ...In this work, the Micropolar fluid flow and heat and mass transfer past a horizontal nonlinear stretching sheet through porous medium is studied including the Soret-Dufour effect in the presence of suction. A uniform magnetic field is applied transversely to the direction of the flow. The governing differential equations of the problem have been transformed into a system of non-dimensional differential equations which are solved numerically by Nachtsheim-Swigert iteration technique along with the sixth order Runge-Kutta integration scheme. The velocity, microrotation, temperature and concentration profiles are presented for different parameters. The present problem finds significant applications in hydromagnetic control of conducting polymeric sheets, magnetic materials processing, etc.展开更多
Objectives:Bangladesh stands as a prominent global consumer of tobacco,with alarming consequences on public health.The Global Adult Tobacco Survey reported that tobacco consumption claimed over 126000 lives in 2018,co...Objectives:Bangladesh stands as a prominent global consumer of tobacco,with alarming consequences on public health.The Global Adult Tobacco Survey reported that tobacco consumption claimed over 126000 lives in 2018,contributing to 13.5%of all deaths in the country.This study aims to explore the effectiveness of higher tax rates and tobacco use regulation as control mechanisms in mitigating tobacco consumption and health care cost burden,with a particular emphasis on its implications for public health.Methods:This study is based on the annual time series data over the period 2000-2020.The study employs the ordinary least square method to analyze the quantitative confirming the stationarity of data at level.This research uses different models to investigate individual effects and combined effects on both tobacco consumption and tobacco health care cost burden.Results:The study finds a negative relationship between tobacco tax rate and tobacco consumption.More specifically,the higher tax rate of tobacco(low(β=-0.3495),medium(β=-0.2319),high(β=-0.9033),premium(β=-0.7322),filtered(β=-0.2114),and non-filtered(β=-0.3452)categories)is significant to reduce tobacco use at 1%level of significance.The study finds similar results when it applied tobacco retail price instead of tobacco tax rate as the independent variable.Finally,the study investigates the impact on health care cost through tobacco consumption,tobacco control law,growth rate,export-import,and tobacco production.The results indicate that tobacco consumption,export-import,and tobacco production increases health care cost burden while tobacco use regulatory decreases it.By reducing tobacco consumption,higher taxes and tobacco use regulation contribute to alleviating the burden on the healthcare system,promoting healthier lifestyles,and aligning with global health objectives.Conclusions:Higher tax rate on tobacco products is necessary to increase the retail price so that tobacco users cannot consume tobacco.Specific tax and uniform tax base are needed so that tobacco users cannot switch to lower priced brands.Tobacco control laws need to revised and proper implementation should be ensured as well,to achieve the goal of tobacco free Bangladesh by 2040.Tobacco-related diseases,responsible for a significant proportion of deaths in the country,could witness a considerable decline with the successful implementation of higher tax rates and tobacco use regulation.This study provides insights that not only contribute to the economic discourse but also accentuate the broader public health benefits arising from effective tobacco taxation policies.展开更多
China‟s growing engagement in various sectors in South Asia poses challenges to India‟s regional dominant position.China has started billions of dollars investment for infrastructure development,especially in those st...China‟s growing engagement in various sectors in South Asia poses challenges to India‟s regional dominant position.China has started billions of dollars investment for infrastructure development,especially in those states who are part of its Belt and Road initiatives(BRI).Indian scholars consider Beijing‟s Indian Ocean centric investment including sea port expansion as a policy of controlling India by creating„string of pearls,‟those small countries as a vital„pearl‟in this„string‟.On the contrary,China claims that it is not anything concerning security in South Asia;rather,she looks for economic gain as well as a win-win situation for all.Except for India,all countries of this region have already welcomed their participation in the BRI.In order to illustrate the opposite perceptions of India and China,the paper aims to explore either China‟s investment in the South Asian region is for its strategic gain or more economic expansions.I argue that China‟s growing influence in South Asia should not be considered as a strategy of„encirclement‟against India.Nevertheless,the article concludes here if New Delhi and Beijing is looking forward to making a success of BRI,it certainly will bring crucial geopolitical and economic gain.展开更多
An analysis of two-dimensional steady magneto-hydrodynamic free convection flow of an electrically conducting, viscous, incompressible fluid past an inclined stretching porous plate in the presence of a uniform magnet...An analysis of two-dimensional steady magneto-hydrodynamic free convection flow of an electrically conducting, viscous, incompressible fluid past an inclined stretching porous plate in the presence of a uniform magnetic field and thermal radiation with heat generation is made. Both the Dufour and Soret effects are considered for a hydrogen-air mixture as the non-chemically reacting fluid pair. The equations governing the flow, temperature and concentration fields are reduced to a system of joined non-linear ordinary differential equations by similarity transformation. Non-linear differential equations are integrated numerically by using Nachtsheim-Swigert shooting iteration technique along with sixth order Runge-Kutta integration scheme. Finally the significance of physical parameters which are of engineering interest are examined both in graphical and tabular form.展开更多
The present study concentrates on the analysis of MHD free convection flow past an inclined stretching sheet. The viscous dissipation and radiation effects are assumed in the heat equation. Approximation solutions hav...The present study concentrates on the analysis of MHD free convection flow past an inclined stretching sheet. The viscous dissipation and radiation effects are assumed in the heat equation. Approximation solutions have been derived for velocity, temperature, concentration, Nusselt number, skin friction and Sherwood number using Nachtsheim-Swigert shooting iteration technique along with the six-order Runge-Kutta iteration scheme. Graphs are plotted to find out the characteristics of different physical parameters. The variations of physical parameters on skin friction coefficient, Nusselt number and Sherwood number are displayed via table.展开更多
Mixed convective flow of a viscous incompressible electrically conducting micropolar fluid along a semi-infinite inclined permeable flat plate with viscous dissipation has been analyzed numerically. With appropriate t...Mixed convective flow of a viscous incompressible electrically conducting micropolar fluid along a semi-infinite inclined permeable flat plate with viscous dissipation has been analyzed numerically. With appropriate transformations the boundary layer equations are transformed into a set of nonlinear ordinary differential equations. The local similarity solutions of the transformed dimensionless equations for the flow, microrotation and the heat transfer characteristics are evaluated using Nachtsheim-Swigert shooting iteration technique (guessing the missing value) together with sixth order Runge-Kutta-Butcher integration scheme. Numerical results are presented in the form of non-dimensional velocity, microrotation and temperature profiles within the boundary layer for different parameters entering into the analysis. The effects of pertinent parameters on the local skin friction coefficient (viscous drag), plate couple stress and rate of heat transfer (Nusselt number) are also displayed graphically.展开更多
This paper reflects the scopes of accelerator driven system (ADS) based nuclear energy, as a reliable source of electric energy generation, comparing to the other existing non-renewable and renewable sources. There ar...This paper reflects the scopes of accelerator driven system (ADS) based nuclear energy, as a reliable source of electric energy generation, comparing to the other existing non-renewable and renewable sources. There are different limitations in the use of every source of electric energy but in consideration of minimum environmental impact, exclusively inherently low greenhouse gas (GHG) emission, and also, high life time with maximum power production efficiency, nuclear would be the best choice. From this study it was found that several difficulties involved in the ADS based energy production, more specifically, difficulties regarding the target parameters, coding system, waste management, etc. Hence suggestions from this study points out that if it is possible to ensure more energy efficient production of enriched uranium, improved nuclear fuels and reactors that allow greater utilization, extended life times for nuclear power plants (NPPs) that reduce the need to build new facilities, improved coding system capable of minimizing the discrepancy between theoretical and experimental calculation of spallation products, improved data library with sufficiently available high energy nuclear data to perform a better coding analysis, and finally, considering the environmental safety if the disposal of the radioactive wastes could manage more effectively, nuclear energy would then play a significant role in minimizing future energy crisis worldwide as well as to save our loving green earth.展开更多
文摘The standard solid-state reaction method was employed to synthesize the polycrystalline Ca0.9Sr0.1Mn1−xMoxO3 (CSMMO with x = 0.00, 0.02, 0.04, 0.06, and 0.08) ceramics and each composition was sintered at 1300˚C for 4 hours. The crystal structure, microstructure, optical properties, electrical properties, complex initial permeability, and DC magnetization of the prepared compositions were carried out. The compound exhibited perovskite structure with the transformation of phase from orthorhombic symmetry for x = 0.00 to x = 0.04 samples into a tetragonal symmetry for the samples x = 0.06 and x = 0.08. The lattice constant was found to be enhanced with the doping of Mo concentration. The mean grain size was estimated in the micrometer, with values from 1.3045 to 3.0124 µm. Energy band gap (Eg) was determined for each composition and the magnitudes of Eg were lying between 1.85 - 4.00 eV. The Eg values firstly decreased with the doping content up to 2% and, then, increased for 4% to 6% Mo contents, where it again very slightly decreased for 8% Mo content. The lowest value of Eg was obtained for the x = 0.02 composition. The FTIR spectra revealed the existence of a metal oxide band in each of the prepared samples and supported the formation of a single-phase compound of synthesized material without any impurity, as confirmed by the XRD analysis. The electrical properties, such as resistivity and AC conductivity, were collected using the Impedance analyzer at room temperature. The resistivity and AC conductivity increased with the addition of dopant concentration. The frequency-dependent conductivity spectra showed three distinct regions. The complex initial permeability (μ′) was found to be enhanced with the addition of Mo and the highest value was noticed the 6% Mo dopant sample. On the other hand, the lowest loss factor was obtained for the samples x ≥ 0.06. The M-H hysteresis loops of various Ca0.9Sr0.1Mn1−xMoxO3 ceramics were measured both at room temperature (300 K) and low temperature (5 K). The values of saturation magnetization (Ms) and retentivity (Mr) were found to be larger at low temperatures than at room temperature (RT), although no saturation was obtained for any compositions. The highest saturation magnetization obtained at room temperature for the x = 0.06 sample was 0.8581 emu/g.
文摘A study has been arranged to investigate the flow of non-Newtonian fluid in a vertical asymmetrical channel using peristalsis. The porous medium allows the electrically conductive fluid to flow in the channel, while a uniform magnetic field is applied perpendicular to the flow direction. The analysis takes into account the combined influence of heat and mass transfer, including the effects of Soret and Dufour. The flow’s non-Newtonian behavior is characterized using a Casson rheological model. The fluid flow equations are examined within a wave frame of reference that has a wave velocity. The analytic solution is examined using long wavelengths and a small Reynolds number assumption. The stream function, temperature, concentration and heat transfer coefficient expressions are derived. The bvp4c function from MATLAB has been used to numerically solve the transformed equations. The flow characteristics have been analyzed using graphs to demonstrate the impacts of different parameters.
文摘The fundamental frequency plays a significant part in understanding and perceiving the pitch of a sound. The pitch is a fundamental attribute employed in numerous speech-related works. For fundamental frequency extraction, several algorithms have been developed which one to use relies on the signal’s characteristics and the surrounding noise. Thus, the algorithm’s noise resistance becomes more critical than ever for precise fundamental frequency estimation. Nonetheless, numerous state-of-the-art algorithms face struggles in achieving satisfying outcomes when confronted with speech recordings that are noisy with low signal-to-noise ratio (SNR) values. Also, most of the recent techniques utilize different frame lengths for pitch extraction. From this point of view, This research considers different frame lengths on male and female speech signals for fundamental frequency extraction. Also, analyze the frame length dependency on the speech signal analytically to understand which frame length is more suitable and effective for male and female speech signals specifically. For the validation of our idea, we have utilized the conventional autocorrelation function (ACF), and state-of-the-art method BaNa. This study puts out a potent idea that will work better for speech processing applications in noisy speech. From experimental results, the proposed idea represents which frame length is more appropriate for male and female speech signals in noisy environments.
文摘The aim of the study was to investigate the factors affecting consumers’internet shopping behavior during the coronavirus disease(COVID-19)pandemic in Bangladesh.The study measured the influence of product factor,price factor,time saving factor,payment factor,security factor,administrative factor,and psychological factor on consumers’internet shopping behavior during the coronavirus disease(COVID-19)pandemic.The research collected data from May 10,2020 to June 10,2020 in personal interview by online survey method through a structured questionnaire with five-point Likert scales from 230 Bangladeshi online consumers.Non-probability sampling method was used.Data were analyzed using descriptive statistics analysis,reliability analysis,and multiple regression analysis.Results exhibited that all factors except price factor and security factor had a momentous and positive association with consumers’internet shopping behavior during the coronavirus disease(COVID-19)pandemic in Bangladesh.It has implications for e-marketing practicing firms regarding the real strategy of online shopping for Bangladeshi consumers during the coronavirus disease(COVID-19)pandemic in Bangladesh.
文摘Palm fiber (PF) reinforced acrylonitrile butadiene styrene (ABS) composite matrix was prepared by employing Injection Moulding Machine (IMM). Palm fiber was collected from ten different trees of different age group from Comilla region in Bangladesh. Three sets of samples were prepared for three different wt% (5%, 10% and 20%) of fiber contents. The mechanical (tensile strength, flexural stress, micro hardness, Leeb’s rebound hardness) and physical (bulk density and water absorption) properties were measured. The observed result reveals that the tensile strength (TS) and flexural stress (FS) were decreased with increasing fiber contents in the PF-ABS composites except 10% fiber content.
文摘An analysis of Thermophoresis effect on unsteady magneto-hydrodynamic free convection flow over an inclined porous plate with time dependent suction in presence of magnetic field with heat generation has been considered by employing Nachtsheim-Swigert shooting iteration technique along with sixth order Runge-Kutta integration scheme. Resulting non-dimensional velocity, temperature and concentration profiles are then presented graphically for different values of the parameters entering into the problem. Finally, the effects of the pertinent parameters on the skin-friction coefficient, the rate of heat transfer (Nusselt number) and wall deposition flux (Stanton number), which are of physical interest, are exhibited in tabular form.
文摘The energy demand in Australia is increasing with the industrialization and rapid economic growth.This study analyzed the relationships among the economic growth,Foreign Direct Investment(FDI),trade openness,urbanization,and energy usage in Australia based on the data from World Development Indicators(WDI)from 1972 to 2021.The results indicates that there is a cointegration among economic growth,FDI,trade openness,urbanization,and energy usage,which was traced through the autoregressivedistributed lag(ARDL).The Zivot-Andrews unit root test reveals that energy usage,economic growth,FDI,urbanization,and trade openness show significant structural breaks in 1993,1996,1982,2008,and 1994,respectively.The ARDL model shows that economic growth has a positive and significant effect on energy usage in the long-run(0.814)and short-run(0.809).Moreover,the results also show that FDI(0.028)and trade openness(0.043)have positive impacts on energy usage in the long-run.However,urbanization shows a negative and significant influence on energy usage in the long-run(–0.965).Then,the research demonstrates a unidirectional causation between energy usage and trade openness,with energy usage significantly causing trade openness.The current study endorses energy consumption policies and investment strategies for a paradigm shifting from a reliance on fossil fuels as the primary energy source to renewable energy sources.These findings have profound implications for sustainable energy usage.
文摘The novel polycrystalline Bi<sub>0.85</sub>Gd<sub>0.15</sub>Cu<sub>x</sub>Fe<sub>1-x</sub>O<sub>3</sub> (x = 0, 0.025, 0.05, 0.075, 0.10) multiferroics are synthesized by the usual solid-state reaction route. The synthesis of the desired phase has been verified by the X-ray Diffraction (XRD) patterns. With major structural phases, few traces of secondary phases of Bi<sub>2</sub>Fe<sub>4</sub>O<sub>9</sub> and Bi<sub>25</sub>FeO<sub>40</sub> appear for all the compositions. A discontinuous series of structural changes with varying compositions are observed for the doped samples. The bulk density (ρ<sub>B</sub>) increases with Cu content reaches the highest at x = 0.05 and then declines. The complex initial permeability and dielectric characterizations are performed by Wayne Kerr Impedance Analyzer. The x = 0.05 samples having maximum density exhibit the highest permeability (μ<sub>i</sub>’) implying a close relation between μ<sub>i</sub>’ and the density. The reduction of μ<sub>i</sub>’ at higher Cu concentration is due to the low density of the samples associated with the increased intragranular pores. The dielectric constant (ε’) is measured against frequency in the range 1 kHz - 10 MHz. It is perceived that ε’ falls with the rise in frequency up to 100 kHz. This dielectric dispersion is observed at a lower frequency as a result of interfacial polarization outlined by Maxwell-Wagner. The maximum ε’ is obtained for x = 0.025 composition. In the low-frequency range, the AC conductivity σ<sub>AC</sub> is practically independent of frequency and resembles the DC conductivity (σ<sub>DC</sub>). In the vicinity of high frequency recognized as the hopping region, σ<sub>AC</sub> rises since the conductive grains are more active at high frequencies. The co-doping with Gd and Cu in BiFeO<sub>3</sub> ceramics enhances the magnetic and dielectric properties of the ceramics and hence can be utilized for fabricating multifunctional devices.
文摘A study on the detection of probable radionuclides and their activity concentrations in the raw material (phosphate rock), final product (fertilizer) and waste samples collected from all the phosphate fertilizer factories (total two factories—A Diammonium Phosphate, DAP and a Triple Super Phosphate, TSP factory) in Bangladesh were carried out. A total of seven types of samples (grossly divided into solid and liquid types);liquid waste, waste-mixed river water, normal river water, phosphate rock, phosphate fertilizer, solid waste and normal soil;were analyzed under this study. Raw material samples were collected only from the TSP fertilizer factory. Fertilizer, solid and liquid waste samples were collected from both the factories under study. Moreover, normal soil and natural surface water samples from the suitable areas adjacent to the factories were also collected for the comparison purpose. The samples were analyzed by gamma ray spectrometry technique using a Hyper-Pure Germanium (HPGe) detector of 40% relative efficiency. The analysis of the samples showed that only natural radionuclides such as 226Ra, 232Th and 40K were present in the samples and no traces of artificial radioactivity were found in any of the samples. 40K was found below the detection limit in some samples. The analysis of the samples in the case of TSP fertilizer factory showed that the average activity concentrations of 226Ra and 232Th and 40K in raw materials were 851.27 ± 7.10, 19.63 ± 6.57 and 54.06 ± 5.93 Bq/kg, respectively, in final product 211.90 ± 4.74, 42.48 ± 10.56 Bq/kg and ND (Not Detected), respectively, in solid waste 187.49 ± 4.88, 70.06 ± 11.76 and 289.27 ± 40.24 Bq/kg, respectively and in liquid waste 6.26 ± 0.63, 10.01 ± 1.39 Bq/L and ND, respectively. The measured results in the case of samples collected from DAP fertilizer factory showed that the average activity concentrations of 226Ra and 232Th and 40K in the final product were 17.31 ± 3.92, 69.74 ± 9.88 and 48.46 ± 17.22 Bq/kg, respectively, in solid waste 24.47 ± 4.15, 164.62 ± 11.08, 191.52 ± 33.74 Bq/kg, respectively and in liquid waste 3.59 ± 1.05, 37.08 ± 3.30 Bq/L and ND, respectively. Considering the stored raw materials and wastes the part of the ambient environment of the factory, radium equivalent activity, radiation hazard index and external annual effective dose to the workers and public due to these materials were also calculated and compared with world average values.
文摘Zinc Sulfide (ZnS) thin film has attracted increasing attention due to their potential applications in the new generation of nano-electronics and opto-electronics devices. The physical and chemical properties of ZnS have outstanding quality for different applications. Moreover, ZnS doped with various elements are creating a new era for both academic research and industrial applications. So, the optical properties of modified ZnS thin film will help us to find a suitable doping element for convenient deposition which may enhance the conductance and transmitting properties of the film. This review work has been carried out to explore the four-modification elements that constitute Cu, Ni, Co & Fe as descending order of atomic number corresponding to Zn, along with some potential applications considering the recent research work with other doping elements too such as Al, C, Pt etc. For example, FE, FET, Catalytic, Solar cell, Electroluminescence, Fuel cell, different sensors (Chemical sensors, Bio-sensors, Humidity sensors, light sensors, UV light sensors) and nanogenerators use ZnS thin film.
文摘With the aid of Injection Moulding Machine (IMM) Palm fiber reinforced Acrylonitrile Butadiene Styrene (ABS) composites (PF-ABS) were prepared. Three sets of samples were prepared for three different wt% (5%, 10% and 20%) of fiber contents. Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) experiments were performed to study the surface morphology, microstructure (if it crystalline or noncrystalline) and new bond formation after preparation of the composites. SEM pattern shows that after addition of palm fiber in PF-ABS composites the brittleness increased due to creation of voids in the composites except 10% fiber content in PF-ABS. From XRD pattern it is clear that the palm fiber, ABS and PF-ABS composites are amorphous in nature. Moreover FTIR spectrum shows that there is no new bond formed after addition of palm fiber in ABS polymeric matrix to create PF-ABS composites.
文摘We introduce a new integral scheme namely improved Kudryashov method for solving any nonlinear fractional differential model.Specifically,we apply the approach to the nonlinear space-time fractional model leading the wave to spread in electrical transmission lines(s-tfETL),the time fractional complex Schrödinger(tfcS),and the space-time M-fractional Schrödinger-Hirota(s-tM-fSH)models to verify the effectiveness of the proposed approach.The implementing of the introduced new technique based on the models provides us with periodic envelope,exponentially changeable soliton envelope,rational rogue wave,periodic rogue wave,combo periodic-soliton,and combo rational-soliton solutions,which are much interesting phenomena in nonlinear sciences.Thus the results disclose that the proposed technique is very effective and straight-forward,and such solutions of the models are much more fruitful than those from the generalized Kudryashov and the modified Kudryashov methods.
基金UPNM Grant J0117-UPNM/2016/GPJP/5/ICT/2.The authors fully acknowledged Ministry of Higher Education(MOHE)and National Defence University of Malaysia for the approved fund which makes this important research viable and effective.The authors also would like to thank University Grant Commission of Bangladesh,Comilla University for the financial support.
文摘Pocket Switched Networks(PSN)represent a particular remittent network for direct communication between the handheld mobile devices.Compared to traditional networks,there is no stable topology structure for PSN where the nodes observe the mobility model of human society.It is a kind of Delay Tolerant Networks(DTNs)that gives a description to circulate information among the network nodes by the way of taking the benefit of transferring nodes from one area to another.Considering its inception,there are several schemes for message routing in the infrastructure-less environment in which human mobility is only the best manner to exchange information.For routing messages,PSN uses different techniques such asDistributed Expectation-Based Spatio-Temporal(DEBT)Epidemic(DEBTE),DEBT Cluster(DEBTC),and DEBT Tree(DEBTT).Understanding on how the network environment is affected for these routing strategies are the main motivation of this research.In this paper,we have investigated the impact of network nodes,the message copies per transmission,and the overall carrying out of these routing protocols.ONE simulator was used to analyze those techniques on the basis of delivery,overhead,and latency.The result of this task demonstrates that for a particular simulation setting,DEBTE is the best PSN routing technique among all,against DEBTC and DEBTT.
文摘In this work, the Micropolar fluid flow and heat and mass transfer past a horizontal nonlinear stretching sheet through porous medium is studied including the Soret-Dufour effect in the presence of suction. A uniform magnetic field is applied transversely to the direction of the flow. The governing differential equations of the problem have been transformed into a system of non-dimensional differential equations which are solved numerically by Nachtsheim-Swigert iteration technique along with the sixth order Runge-Kutta integration scheme. The velocity, microrotation, temperature and concentration profiles are presented for different parameters. The present problem finds significant applications in hydromagnetic control of conducting polymeric sheets, magnetic materials processing, etc.
文摘Objectives:Bangladesh stands as a prominent global consumer of tobacco,with alarming consequences on public health.The Global Adult Tobacco Survey reported that tobacco consumption claimed over 126000 lives in 2018,contributing to 13.5%of all deaths in the country.This study aims to explore the effectiveness of higher tax rates and tobacco use regulation as control mechanisms in mitigating tobacco consumption and health care cost burden,with a particular emphasis on its implications for public health.Methods:This study is based on the annual time series data over the period 2000-2020.The study employs the ordinary least square method to analyze the quantitative confirming the stationarity of data at level.This research uses different models to investigate individual effects and combined effects on both tobacco consumption and tobacco health care cost burden.Results:The study finds a negative relationship between tobacco tax rate and tobacco consumption.More specifically,the higher tax rate of tobacco(low(β=-0.3495),medium(β=-0.2319),high(β=-0.9033),premium(β=-0.7322),filtered(β=-0.2114),and non-filtered(β=-0.3452)categories)is significant to reduce tobacco use at 1%level of significance.The study finds similar results when it applied tobacco retail price instead of tobacco tax rate as the independent variable.Finally,the study investigates the impact on health care cost through tobacco consumption,tobacco control law,growth rate,export-import,and tobacco production.The results indicate that tobacco consumption,export-import,and tobacco production increases health care cost burden while tobacco use regulatory decreases it.By reducing tobacco consumption,higher taxes and tobacco use regulation contribute to alleviating the burden on the healthcare system,promoting healthier lifestyles,and aligning with global health objectives.Conclusions:Higher tax rate on tobacco products is necessary to increase the retail price so that tobacco users cannot consume tobacco.Specific tax and uniform tax base are needed so that tobacco users cannot switch to lower priced brands.Tobacco control laws need to revised and proper implementation should be ensured as well,to achieve the goal of tobacco free Bangladesh by 2040.Tobacco-related diseases,responsible for a significant proportion of deaths in the country,could witness a considerable decline with the successful implementation of higher tax rates and tobacco use regulation.This study provides insights that not only contribute to the economic discourse but also accentuate the broader public health benefits arising from effective tobacco taxation policies.
文摘China‟s growing engagement in various sectors in South Asia poses challenges to India‟s regional dominant position.China has started billions of dollars investment for infrastructure development,especially in those states who are part of its Belt and Road initiatives(BRI).Indian scholars consider Beijing‟s Indian Ocean centric investment including sea port expansion as a policy of controlling India by creating„string of pearls,‟those small countries as a vital„pearl‟in this„string‟.On the contrary,China claims that it is not anything concerning security in South Asia;rather,she looks for economic gain as well as a win-win situation for all.Except for India,all countries of this region have already welcomed their participation in the BRI.In order to illustrate the opposite perceptions of India and China,the paper aims to explore either China‟s investment in the South Asian region is for its strategic gain or more economic expansions.I argue that China‟s growing influence in South Asia should not be considered as a strategy of„encirclement‟against India.Nevertheless,the article concludes here if New Delhi and Beijing is looking forward to making a success of BRI,it certainly will bring crucial geopolitical and economic gain.
文摘An analysis of two-dimensional steady magneto-hydrodynamic free convection flow of an electrically conducting, viscous, incompressible fluid past an inclined stretching porous plate in the presence of a uniform magnetic field and thermal radiation with heat generation is made. Both the Dufour and Soret effects are considered for a hydrogen-air mixture as the non-chemically reacting fluid pair. The equations governing the flow, temperature and concentration fields are reduced to a system of joined non-linear ordinary differential equations by similarity transformation. Non-linear differential equations are integrated numerically by using Nachtsheim-Swigert shooting iteration technique along with sixth order Runge-Kutta integration scheme. Finally the significance of physical parameters which are of engineering interest are examined both in graphical and tabular form.
文摘The present study concentrates on the analysis of MHD free convection flow past an inclined stretching sheet. The viscous dissipation and radiation effects are assumed in the heat equation. Approximation solutions have been derived for velocity, temperature, concentration, Nusselt number, skin friction and Sherwood number using Nachtsheim-Swigert shooting iteration technique along with the six-order Runge-Kutta iteration scheme. Graphs are plotted to find out the characteristics of different physical parameters. The variations of physical parameters on skin friction coefficient, Nusselt number and Sherwood number are displayed via table.
文摘Mixed convective flow of a viscous incompressible electrically conducting micropolar fluid along a semi-infinite inclined permeable flat plate with viscous dissipation has been analyzed numerically. With appropriate transformations the boundary layer equations are transformed into a set of nonlinear ordinary differential equations. The local similarity solutions of the transformed dimensionless equations for the flow, microrotation and the heat transfer characteristics are evaluated using Nachtsheim-Swigert shooting iteration technique (guessing the missing value) together with sixth order Runge-Kutta-Butcher integration scheme. Numerical results are presented in the form of non-dimensional velocity, microrotation and temperature profiles within the boundary layer for different parameters entering into the analysis. The effects of pertinent parameters on the local skin friction coefficient (viscous drag), plate couple stress and rate of heat transfer (Nusselt number) are also displayed graphically.
文摘This paper reflects the scopes of accelerator driven system (ADS) based nuclear energy, as a reliable source of electric energy generation, comparing to the other existing non-renewable and renewable sources. There are different limitations in the use of every source of electric energy but in consideration of minimum environmental impact, exclusively inherently low greenhouse gas (GHG) emission, and also, high life time with maximum power production efficiency, nuclear would be the best choice. From this study it was found that several difficulties involved in the ADS based energy production, more specifically, difficulties regarding the target parameters, coding system, waste management, etc. Hence suggestions from this study points out that if it is possible to ensure more energy efficient production of enriched uranium, improved nuclear fuels and reactors that allow greater utilization, extended life times for nuclear power plants (NPPs) that reduce the need to build new facilities, improved coding system capable of minimizing the discrepancy between theoretical and experimental calculation of spallation products, improved data library with sufficiently available high energy nuclear data to perform a better coding analysis, and finally, considering the environmental safety if the disposal of the radioactive wastes could manage more effectively, nuclear energy would then play a significant role in minimizing future energy crisis worldwide as well as to save our loving green earth.
