Pulsatile flow of blood with shear-dependent viscosity through a flexible stenosed artery in the presence of body acceleration

Subrata Mukhopadhyay,Mani Shankar Mandal,Swati Mukhopadhyay 한국유변학회 2022 Korea-Australia rheology journal Vol.34 No.1

A mathematical model of physiological pulsatile fl ow of blood through a stenotic flexible artery in the presence of body acceleration is presented in this paper. Streaming blood is considered as a shear-thinning non-Newtonian fluid as proposed by Yeleswarapu (Evaluation of continuum models for characterizing the constitutive behaviour of blood, Ph.D. thesis, Dept. Mech. Eng., University of Pittsburgh, 1996), and a physiological pulsatile fl ow rate proposed by Pedrizzetti (J Fluid Mech 310:89–111, 1996) has been taken through the tube. Deformation of vessel wall is modelled as a function of fl ow rate. This computational study of an idealized model may bring some insights for realistic blood fl ow through a stenotic artery. The novelty of this work lies in the fact that realistic fl ow of blood through a stenosed artery has been studied as far as possible and a new idea has been provided to describe the arterial wall motion. Governing equations in cylindrical polar coordinates are solved using stream function–vorticity method. Behaviour of various fl ow quantities is investigated through a parametric study. It is noted that the degree of constriction and body acceleration have important impacts on the haemodynamic parameters such as wall shear stress, oscillatory shear index, and relative residence time. Increasing body acceleration enhances the peak value of wall shear stress, but reduces the oscillatory shear index and relative residence time. Almost 1/4th increase in length of fl ow separation is found when Froude number raises its value from 0.1 to 0.5, other parametric values remaining fixed. On the other hand, almost 50% increase in the magnitude of the peak value of wall pressure is found when the amplitude of body acceleration takes a value 0.4 ( A = 0.4) compared to the without body acceleration case ( A = 0). These results have a significant role.

A Note on Strongly Euclidean Semiring

P. Mukhopadhyay 경북대학교 자연과학대학 수학과 2003 Kyungpook mathematical journal Vol.43 No.2

Structure of ideals in an Euclidean semiring has been studied by Dale L. and Hanson D. L. [1] (1977). Mukhopadhyay in his paper [4] (1999) raised the question "Is every Euclidean semiring a principal k-ideal semiring ?" An answer to this question in the case of inversive semirings is provided in the present paper.

Defining 'Islamic' Urbanity Through A Trans-Regional Frame

Mukhopadhyay, Urvi The Asian Association of World Historians 2015 The Asian review of world histories Vol.3 No.1

The word 'urbanity' literally means 'quality or state of being urban' where the criterion of urban economic and civic culture is assumed despite the general celebration of cultural uniqueness of urban centers. The narratives celebrating the uniqueness of urban centers since the ancient past till recent times could not get rid of the broad categorization of the urban models depending on their contextual networks of trade, mobility and culture. This paper attempts to explore whether the urban cultures in South Asia even preceding a global phenomenon like colonialism were actually reflecting an idea of urbanity where the urban culture, including planning and architecture reflected a trans-national model. This paper particularly concentrates on the medieval period when a pattern of urbanity took shape in this subcontinent under the influence of Islam, which could be explained by its particular idea of urban model, cultural exchange and vibrant trade networks.

Solar tower combined cycle plant with thermal storage: energy and exergy analyses

Mukhopadhyay, Soumitra,Ghosh, Sudip Techno-Press 2016 Advances in energy research Vol.4 No.1

There has been a growing interest in the recent time for the development of solar power tower plants, which are mainly used for utility scale power generation. Combined heat and power (CHP) is an efficient and clean approach to generate electric power and useful thermal energy from a single heat source. The waste heat from the topping Brayton cycle is utilized in the bottoming HRSG cycle for driving steam turbine and also to produce process steam so that efficiency of the cycle is increased. A thermal storage system is likely to add greater reliability to such plants, providing power even during non-peak sunshine hours. This paper presents a conceptual configuration of a solar power tower combined heat and power plant with a topping air Brayton cycle. A simple downstream Rankine cycle with a heat recovery steam generator (HRSG) and a process heater have been considered for integration with the solar Brayton cycle. The conventional GT combustion chamber is replaced with a solar receiver. The combined cycle has been analyzed using energy as well as exergy methods for a range of pressure ratio across the GT block. From the thermodynamic analysis, it is found that such an integrated system would give a maximum total power (2.37 MW) at a much lower pressure ratio (5) with an overall efficiency exceeding 27%. The solar receiver and heliostats are the main components responsible for exergy destruction. However, exergetic performance of the components is found to improve at higher pressure ratio of the GT block.

Mechanistic Investigation of Bis(imino)pyridine Manganese Catalyzed Carbonyl and Carboxylate Hydrosilylation

Mukhopadhyay, Tufan K.,Rock, Christopher L.,Hong, Mannkyu,Ashley, Daniel C.,Groy, Thomas L.,Baik, Mu-Hyun,Trovitch, Ryan J. American Chemical Society 2017 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.139 No.13

<P>We recently reported a bis(imino)pyridine (or pyridine diimine, PDI) manganese precatalyst, (<SUP>Ph2PPr</SUP>PDI)Mn (<B>1</B>), that is active for the hydrosilylation of ketones and dihydrosilylation of esters. In this contribution, we reveal an expanded scope for <B>1</B>-mediated hydrosilylation and propose two different mechanisms through which catalysis is achieved. Aldehyde hydrosilylation turnover frequencies (TOFs) of up to 4900 min<SUP>-1</SUP> have been realized, the highest reported for first row metal-catalyzed carbonyl hydrosilylation. Additionally, <B>1</B> has been shown to mediate formate dihydrosilylation with leading TOFs of up to 330 min<SUP>-1</SUP>. Under stoichiometric and catalytic conditions, addition of PhSiH<SUB>3</SUB> to (<SUP>Ph2PPr</SUP>PDI)Mn was found to result in partial conversion to a new diamagnetic hydride compound. Independent preparation of (<SUP>Ph2PPr</SUP>PDI)MnH (<B>2</B>) was achieved upon adding NaEt<SUB>3</SUB>BH to (<SUP>Ph2PPr</SUP>PDI)MnCl<SUB>2</SUB> and single-crystal X-ray diffraction analysis revealed this complex to possess a capped trigonal bipyramidal solid-state geometry. When 2,2,2-trifluoroacetophenone was added to <B>1</B>, radical transfer yielded (<SUP>Ph2PPr</SUP>PDI<B>·</B>)Mn(OC<B>·</B>(Ph)(CF<SUB>3</SUB>)) (<B>3</B>), which undergoes intermolecular C-C bond formation to produce the respective Mn(II) dimer, [(μ-<I>O</I>,<I>N</I><SUB>py</SUB>-4-OC(CF<SUB>3</SUB>)(Ph)-4-H-<SUP>Ph2PPr</SUP>PDI)Mn]<SUB>2</SUB> (<B>4</B>). Upon finding <B>3</B> to be inefficient and <B>4</B> to be inactive, kinetic trials were conducted to elucidate the mechanisms of <B>1</B>- and <B>2</B>-mediated hydrosilylation. Varying the concentration of <B>1</B>, substrate, and PhSiH<SUB>3</SUB> revealed a first order dependence on each reagent. Furthermore, a kinetic isotope effect (KIE) of 2.2 ± 0.1 was observed for <B>1</B>-catalyzed hydrosilylation of diisopropyl ketone, while a KIE of 4.2 ± 0.6 was determined using <B>2</B>, suggesting <B>1</B> and <B>2</B> operate through different mechanisms. Although kinetic trials reveal <B>1</B> to be the more active precatalyst for carbonyl hydrosilylation, a concurrent <B>2</B>-mediated pathway is more efficient for carboxylate hydrosilylation. Considering these observations, <B>1</B>-catalyzed hydrosilylation is believed to proceed through a modified Ojima mechanism, while <B>2-</B>mediated hydrosilylation occurs via insertion.</P> [FIG OMISSION]</BR>

TEMPORAL AND SPATIO-TEMPORAL DYNAMICS OF A MATHEMATICAL MODEL OF HARMFUL ALGAL INTERACTION

Mukhopadhyay, B.,Bhattacharyya, R. The Korean Society for Computational and Applied M 2009 Journal of applied mathematics & informatics Vol.27 No.1

The adverse effect of harmful plankton on the marine ecosystem is a topic of deep concern. To investigate the role of such phytoplankton, a mathematical model containing distinct dynamical equations for toxic and non-toxic phytoplankton is analyzed. Stability analysis of the resulting three equation model is carried out. A continuous time variation in toxin liberation process is incorporated into the model and a stability analysis of the resulting delay model is performed. The distributed delay model is then extended to include the spatial distribution of plankton and the delay-diffusion model is analyzed with spatial and spatiotemporal kernels. Conditions for diffusion-driven instability in both the cases are derived and compared to explore the significance of these kernels. Numerical studies are performed to justify analytical findings.

Subfertility in Males: An Important Cause of Bull Disposal in Bovines

Mukhopadhyay, C.S.,Gupta, A.K.,Yadav, B.R.,Khate, K.,Raina, V.S.,Mohanty, T.K.,Dubey, P.P. Asian Australasian Association of Animal Productio 2010 Animal Bioscience Vol.23 No.4

The study had two objectives, namely, to estimate the andrological disorders leading to disposal of Karan Fries (KF), Sahiwal cattle and Murrah buffalo bulls and to study the effect of various factors (species/breeds, season of birth and period of birth) on male reproductive parameters. Records on occurrence of subfertility problems and disposal pattern of bulls maintained at the National Dairy Research Institute herd were collected for 15 years (1991 to 2005). Percentage of bulls producing freezable semen was less in the crossbred cattle (58.46%) as compared to Sahiwal (81.69%) and Murrah bulls (81.05%). Various subfertility traits like poor libido and unacceptable seminal profile were found to be the significant reasons (p<0.01) for culling of the breeding bulls. Inadequate sex drive was the main contributing factor for bull disposal in Sahiwal (22.55%) and Murrah bulls (15.12%) whereas poor semen quality and freezability were most frequently observed in KF bulls (24.29 and 7.29 percent, respectively). Least squares analyses of different male reproductive parameters showed that species/breeds had significant effect (p<0.05) on all traits except for frozen semen production periods (FSPP). Periods of birth were significantly different (p<0.05) for all traits except for semen volume. Age at first semen collection (AFSC), age at first semen freezing (AFSF) and age at disposal (AD) were highest in Murrah, while frozen semen production period (FSPP) and semen production period (SPP) were highest in KF and lowest in Sahiwal. The age at first semen donation and breeding period could be reduced by introducing the bulls to training at an early age. These results revealed a declining trend in AFSC, AFSF, FSPP, SPP and AD, thereby indicating an improvement in reproductive performance over the years. The age at first semen donation in bovines can be reduced by introducing the young male calves to training at an early age, which could increase the dosage of semen obtained from each male.

DYNAMICS OF A DELAY-DIFFUSION PREY-PREDATOR MODEL WITH DISEASE IN THE PREY

MUKHOPADHYAY, B.,BHATTACHARYYA, R. 한국전산응용수학회 2005 Journal of applied mathematics & informatics Vol.17 No.1

A mathematical model dealing with a prey-predator system with disease in the prey is considered. The functional response of the predator is governed by a Hoilling type-2 function. Mathematical analysis of the model regarding stability and persistence has been performed. The effect of delay and diffusion on the above system is studied. The role of diffusivity on stability and persistence criteria of the system has also been discussed.

Mechanical Properties of Polypropylene Filaments Drawn on Varying Post Spinning Temperature Gradients

Mukhopadhyay, S.,Deopura, B.L.,Alagirusamy, R. The Korean Fiber Society 2006 Fibers and polymers Vol.7 No.4

High Modulus and high tenacity polypropylene fibers have been prepared by drawing on a gradient heater. Results show that fiber properties are significantly affected by temperature profiles of final stage drawing on a gradient heater. The gradient drawn filaments showed superior mechanical properties when compared to filaments drawn over a constant temperature heater. Fibers with initial modulus of 16.4 GPa and tenacity of 670 MPa have been manufactured in the process. The nature of the gradient drawing had a significant effect on end properties. The superior mechanical properties are attributed to the high crystal perfection and crystallinity and low void fractions obtained at high draw ratios when drawn over a gradient heater.

A retrospective study of mandibular fractures in children

Mukhopadhyay, Santanu The Korean Association of Oral and Maxillofacial S 2018 대한구강악안면외과학회지 Vol.44 No.6

Objectives: The incidence and patterns of mandibular fractures vary by country and population age. This retrospective study evaluated the etiologies and patterns of mandibular fractures in children. Materials and Methods: The clinical records of 89 children (45 males and 44 females) aged 0 to 12 years who presented with mandibular fractures from July 2012 to June 2016 were retrospectively reviewed. The sex, patient age, site of fracture, etiology of trauma, and monthly variations of the fractures were recorded. Descriptive statistics, the z-test and chi-square test were used for statistical analysis and the P-value was set at <0.05. Results: Eighty-nine children (male-to-female ratio 1.02:1) sustained 131 mandibular fractures. Within the study sample, the 6 to 9 year age group most frequently experienced fractures (47.3%). Falls and road traffic accidents (RTA) were the two most common etiological factors that accounted for 44.9% and 24.7% of cases. The condylar fracture was the most common anatomical location (38.9%) followed by the angle (20.6%), parasymphysis (18.3%), body (15.3%), and symphysis (5.3%). A single fracture (51.7%) was more common than multiple fractures (48.3%). The month-wise distribution of mandibular fractures was fairly constant. Conclusion: The condylar region was the most common anatomic site for fractures; in addition, a fall and RTA were the major etiological factors for mandibular fractures. A single fracture was observed in 51.7% of patients while multiple fracture lines accounted for 48.3% of cases.