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Effect of awareness,quarantine and vaccination as control strategies on COVID-19 with Co-morbidity and Re-infection

Infectious Disease Modelling 2022年第4期7卷 660-689页

作者： Amit Kumar Saha Shikha Saha chandra nath podder Department of Mathematics University of DhakaDhaka1000Bangladesh Department of Mathematics Bangladesh University of Engineering and Technology(BUET)Dhaka1000Bangladesh

In this paper,a deterministic compartmental model is presented to assess the impact of vaccination and non-pharmaceutical interventions(social distance,awareness,face mask,and quarantine)on the transmission dynamics of COVID-19 with co-morbidity and reinfection.An expression for the basic reproduction number is then derived for this model.Theoretical analysis shows that the model exhibits backward bifurcation phenomenon when the basic reproduction number is less than unity.But for the case of no reinfection,the model has a globally asymptotically stable disease-free equilibrium(DFE)when the basic reproduction number is less than unity.Furthermore,it is shown that in the case of no re-infection,a unique endemic equilibrium point(EEP)of the model exists which is globally asymptotically stable whenever the reproduction number is greater than unity.From the global sensitivity and uncertainty analysis,we have identified mask coverage,mask efficacy,vaccine coverage,vaccine efficacy,and contact rate as the most influential parameters influencing the spread of COVID-19.Numerical simulation results show that the use of effective vaccines with proper implementation of non-pharmaceutical interventions could lead to the elimination of COVID-19 from the community.Numerical simulations also suggest that the control strategy that ensures a continuous and effective mass vaccination program is the most cost-effective control strategy.The study also shows that in the presence of any co-morbidity and with the occurrence of re-infection,the disease burden may increase.

关键词： COVID-19 Co-morbidity Face-mask Quarantine Vaccination Optimal control Re-infection

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Dynamics of novel COVID-19 in the presence of Co-morbidity

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Infectious Disease Modelling 2022年第2期7卷 138-160页

作者： Amit Kumar Saha chandra nath podder Ashrafi Meher Niger Department of Mathematics University of DhakaDhaka1000Bangladesh

A novel coronavirus(COVID-19)has emerged as a global serious public health issue from December 2019.People having a weak immune system are more susceptible to coronavirus infection.It is a double challenge for people of any age with certain underlying medical conditions including cardiovascular disease,diabetes,high blood pressure and cancer etc.Co-morbidity increases the probability of COVID-19 complication.In this paper a deterministic compartmental model is formulated to understand the transmission dynamics of COVID-19.Rigorous mathematical analysis of the model shows that it exhibits backward bifurcation phenomenon when the basic reproduction number is less than unity.For the case of no re-infection it is shown that having the reproduction number less than one is necessary and sufficient for the effective control of COVID-19,that is,the disease free equilibrium is globally asymptotically stable when the reproduction threshold is less than unity.Furthermore,in the absence of reinfection,a unique endemic equilibrium of the model exists which is globally asymptotically stable whenever the reproduction number is greater than unity.Numerical simulations of the model,using data relevant to COVID-19 transmission dynamics,show that the use of efficacious face masks publicly could lead to the elimination of COVID-19 up to a satisfactory level.The study also shows that in the presence of co-morbidity,the disease increases significantly.

关键词： COVID-19 Co-morbidity Face-mask

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Texture coefficient and band gap tailoring of Fe-doped SnO_(2) nanoparticles via thermal spray pyrolysis

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Rare Metals 2022年第4期41卷 1332-1341页

作者： Majibul Haque Babu Bidhan chandra Dev Jiban podder Department of Physics Bangladesh University of Engineering and TechnologyDhaka 1000Bangladesh

An investigation of Fe-doping effect on SnO_(2) thin films was performed in this study using thermal spray pyrolysis(TSP) method.The surface morphology and structural,optical and electrical properties were studied by field energy scanning electron microscope(FESEM),X-ray diffraction(XRD),ultraviolet-visible(UV-Vis) spectroscopy and four-point probe method.FES EM images demonstrate that the surface morphology of the as-deposited films varies when Fe-doping content varies.XRD studies reveal that crystallite size and preferential growth orientations of the films are dependent on Fe-doping concentrations.The grain size is found to decrease with the increase in Fe content.These studies also specify that the films have tetragonal rutile-type structure with mixed secondary phases.The texture coefficient value of(110) plane increases with the concomitant in-plane(220) decrease in higher doping concentrations.The resistivity and the optical absorbance are found to increase with Fe concentration.The direct optical band gap decreases from 3.94 to3.52 eV with increasing Fe content.

关键词： SnO_(2)thin film Thermal spray pyrolysis Texture coefficient Optical band gap

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Pressure-Induced Instability Characteristics of a Transient Flow and Energy Distribution through a Loosely Bent Square Duct

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Energy Engineering 2022年第1期119卷 429-451页

作者： Sreedham chandra Adhikari Ratan Kumar Chanda Sidhartha Bhowmick Rabindra nath Mondal Suvash chandra Saha Department of Mathematics Jagannath UniversityDhaka1100Bangladesh School of Mechanical and Mechatronic Engineering University of Technology SydneyNew South WalesAustralia

Due to widespread applications of the bent ducts in engineering fields such as in chemical,mechanical,bio-mechanical and bio-medical engineering,scientists have paid considerable attention to invent new characteristics of fluid flow in a bent duct(BD).In the ongoing study,a spectral-based numerical technique is applied to explore flow characteristics and energy distribution through a loosely bent square duct(BSD)of small curvature.Flow is accelerated due to combined action of the non-dimensional parameters;the Grashof number Gr(=1000),the curvatureδ(=0.001),and the Prandtl number Pr(=7.0)over a wide domain of the Dean number 0

关键词： Square-shaped duct curvature secondary flow energy distribution chaos

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Improvements after mod Quad and triangle tilt revision surgical procedures in obstetric brachial plexus palsy

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World Journal of Orthopedics 2016年第11期7卷 752-757页

作者： Rahul K nath chandra Somasundaram Texas Nerve and Paralysis Institute

AIM To compare outcomes of our revision surgical operations in obstetric brachial plexus palsy(OBPP) patients to results of conventional operative procedures at other institutions. METHODS We analyzed our OBPP data and identified 10 female and 10 male children aged 2.0 to 11.8 years(average age 6.5 years), who had prior conventional surgical therapies at other clinics. Of the 20 patients, 18 undergone triangle tilt, 2 had only mod Quad. Among 18 patients, 8 had only triangle tilt and 10 had also mod Quad as revision surgeries with us. We analyzed the anatomical improvements and functional modified Mallet statistically before and after a year post-revision operations.RESULTS Pre-revision surgery average modified Mallet score was 12.0 ± 1.5. This functional score was greatly improved to 18 ± 2.3(P < 0.0001) at least one-year after revision surgical procedures. Radiological scores(PHHA and glenoid version) were also improved significantly to 31.9 ± 13.6(P < 0.001),-16.3 ± 11(P < 0.0002), at least one-year after triangle tilt procedure. Their mean pretriangle tilt(yet after other surgeon's surgeries) PHHA, glenoid version and SHEAR were 14.6 ± 21.7,-31.6 ± 19.3 and 16.1 ± 14.7 respectively.CONCLUSION We demonstrate here, mod Quad and triangle tilt assuccessful revision surgical procedures in 20 OBPP patients, who had other surgical treatments at other clinics before presenting to us for further treatment.

关键词： Revision surgery Obstetric brachial plexus palsy Shoulder movements Joint incongruity Upper limb

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Extraction of locked-up coal by strengthening of rib pillars with FRP--A comparative study through numerical modelling

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International Journal of Mining Science and Technology 2017年第2期27卷 261-267页

作者： Das Arka Jyoti Mandal Prabhat Kumar Ghosh chandra nath Sinha Amalendu CSIR-Central Institute of Mining and Fuel Research Dhanbad 826001India

In some of the coalfields in India, coal seams are only developed but no extraction of pillars is possible due to the presence of surface or sub-surface structures and also non-availability of stowing materials which leads to huge amounts of coal being locked-up underground. Spontaneous heating and fire, accumulation of poisonous gases, severe stability issues leading to unsafe workings and environmental hazards are the major problems associated with the developed coal pillars. So, there is a pressing need for a technology for the mining industry to extract the huge amount of coal locked-up under different constraints. In this study, the locked-up coal is proposed to be extracted by artificially strengthening the rib pillars. The detailed comparative study is carried out to know the increase of extraction percentage of locked-up coal by strengthening the rib pillars with FRP. Extraction methodology is designed and studied through numerical modelling for its stability analysis to evaluate its suitability of application in underground.

关键词： FRP加固数值模拟提取率煤田肋柱表面结构稳定性分析充填材料

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Drag reduction by application of aerodynamic devices in a race car

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Advances in Aerodynamics 2021年第1期3卷 66-85页

作者： Devang S.nath Prashant chandra Pujari Amit Jain Vikas Rastogi Department of Mechanical Engineering Delhi Technological UniversityDelhi 110042India

In this era of fast-depleting natural resources,the hike in fuel prices is ever-growing.With stringent norms over environmental policies,the automotive manufacturers are on a voyage to produce efficient vehicles with lower emissions.High-speed cars are at a stake to provide uncompromised performance but having strict rules over emissions drives the companies to approach through a different route to keep the demands of performance intact.One of the most sought-after ways is to improve the aerodynamics of the vehicles.Drag force is one of the major setbacks when it comes to achieving high speeds when the vehicle is in motion.This research aims to examine the effects of different add on devices on the vehicle to reduce drag and make the vehicle aerodynamically streamlined.A more streamlined vehicle will be able to achieve high speeds and consequently,the fuel economy is also improved.The three-dimensional car model is developed in SOLIDWORKS v17.Computational Fluid Dynamics(CFD)is performed to understand the effects of these add on devices.CFD is carried out in the ANSYS^(TM) 17.0 Fluent module.Drag Coefficient(CD),Lift Coefficient(CL),Drag Force and Lift Force are calculated and compared in different cases.The result of the simulations was analyzed and it was observed that different devices posed several different functionalities,but maximum drag reduction was found in the case of GT with spoiler and diffuser with a maximum reduction of 16.53%.

关键词： Aerodynamics CFD Drag force Drag coefficient High speed car

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Combine Harvester: Small Machine Solves Big Rice Harvesting Problem of Bangladesh

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Agricultural Sciences 2022年第2期13卷 201-220页

作者： Bidhan chandra nath Subrata Paul Md Durrul Huda Md Anwar Hossen MGK Bhuiyan AKM Saiful Islam Bangladesh Rice Research Institute Gazipur Bangladesh

Bangladesh, a country with 87% of rural households that depend on agriculture and rice dominated diets (70%), engages the country’s food security. Therefore, there is strong advocacy for a mechanized paddy harvesting system for food security in South Asia, mainly Bangladesh. Some harvesting machinery is available;however, the precise roles of a combine harvester during this process are little. This study attempts to understand the consequences of combining harvesters for paddy harvesting and compare them with hand harvesting. For comparison of field performance of combine harvester with traditional harvesting, the experiment was conducted at Gazipur District, Bangladesh, in 2016. Results showed that the labor required for harvesting unit area 283, 15 and 9.87 man-h∙ha−1 for T1 (Sickle + Head carry + Beating + Kula), T2 (Reaper + Trolley carry + Close drum thresher + winnower), T3 (Combine harvester) system, respectively. Likewise, the harvesting costs were 1.84 (T2) and 2.5 (T1) times higher than the combine harvester (T3). Also, the postharvest loss can be saved 1.84%, to use combine harvester over manual harvesting of paddy. The above result revealed that the semi-mechanized and mechanized harvesting system is a time, labor and cost-saving system;however, the manual reaping system is concerned with more postharvest losses (3.09%). This study highlights the importance of combine harvester;however, further research is required in other places with large and mini-combine harvesters under diverse cropping areas and to test a combine harvester’s detailed potentiality.

关键词： Combine Harvester Harvesting Labor Paddy Postharvest Losses

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Mathematical Analysis of Nipah Virus Infections Using Optimal Control Theory

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Journal of Applied Mathematics and Physics 2016年第6期4卷 1099-1111页

作者： Jakia Sultana chandra N. podder Department of Computer Science and Engineering Green University of Bangladesh Dhaka Bangladesh Department of Mathematics University of Dhaka Dhaka Bangladesh

The optimal use of intervention strategies to mitigate the spread of Nipah Virus (NiV) using optimal control technique is studied in this paper. First of all we formulate a dynamic model of NiV infections with variable size population and two control strategies where creating awareness and treatment are considered as controls. We intend to find the optimal combination of these two control strategies that will minimize the cost of the two control measures and as a result the number of infectious individuals will decrease. We establish the existence for the optimal controls and Pontryagin’s maximum principle is used to characterize the optimal controls. The numerical simulation suggests that optimal control technique is much more effective to minimize the infected individuals and the corresponding cost of the two controls. It is also monitored that in the case of high contact rate, controls have to work for longer period of time to get the desired result. Numerical simulation reveals that the spread of Nipah virus can be controlled effectively if we apply control strategy at early stage.

关键词： Nipah Virus (NiV) Optimal Control Existence of the State Existence of the Objective Functional Pontryagin’s Maximum Principle Transversality Condition Optimality Condition Hamiltonian (H)

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Understanding Brown Planthopper Resistance in Rice: Genetics, Biochemical and Molecular Breeding Approaches

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Rice science 2021年第6期28卷 532-546页

作者： Lakesh MUDULI Sukanta Kumar PRADHAN Abinash MISHRA Debendra nath BASTIA Kailash chandra SAMAL Pawan Kumar AGRAWAL Manasi DASH Department of Plant Breeding and Genetics College of AgricultureOdisha University ofAgriculture and TechnologyBhubaneswar 751003OdishaIndia Department of Bioinformatics Centre for Post Graduate StudiesOdisha University of Agriculture and TechnologyBhubaneswar 751003OdishaIndia Department of Agricultural Biotechnology College of AgricultureOdisha University of Agriculture and TechnologyBhubaneswar 751003OdishaIndia

Brown planthopper(BPH,Nilaparvata lugens St自I)is the most devastating pest of rice in Asia and causes significant yield loss annually.Around 37 BPH resistance genes have been identified so far in indica,African rice varieties along with wild germplasms such as Oryza officinalis,O.minuta,O.nivara,O.punctata,O.rufipogon and O,latifolia.Genes/QTLs involved in BPH resistance,including Bph1,bph2/BPH26,Bph3,Bph6,bph7,BPH9,Bph12,Bph14,Bph15,Bph17,BPH18,bph19,Bph20,Bph21(t),Bph27,Bph27©Bph28(t),BPH29,QBph3,QBph4,QBph4.2,Bph30,Bph32,Bph33,Bph35 and Bph36,have been fine-mapped by different researchers across the globe.The majority of genes/QTLs are located on rice chromosomes 1,3,4,6,11 and 12.Rice plants respond to BPH attack by releasing various endogenous metabolites like proteinase inhibitors,callose,secondary metabolites(terpenes,alkaloids,flavonoid,etc.)and volatile compounds.Besides that,hormonal signal pathways mediating(antagonistic/synergistic)resista nee responses in rice have been well studied.Marker-assisted breedi ng and genome editi ng techniq ues can also be adopted for improving resista nee to novel BPH biotypes.

关键词： rice brown planthopper resista nee wild germplasm marker-assisted breedi ng genome editing secondary metabolite

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