INTEGRABILITY OF DISTRIBUTIONS IN GCR-LIGHTLIKE SUBMANIFOLDS OF INDEFINITE KAEHLER MANIFOLDS

Kumar, Rakesh,Kumar, Sangeet,Nagaich, Rakesh Kumar Korean Mathematical Society 2012 대한수학회논문집 Vol.27 No.3

In present paper we establish conditions for the integrability of various distributions of GCR-lightlike submanifolds and obtain conditions for the distributions to define totally geodesic foliations in GCR-lightlike submanifolds.

Syringomyelia Associated with Spinal Dural Arteriovenous Fistula: Clinical and Radiological Improvement after Embolization

Singh Rakesh,Deshmukh Narayan,Lalla Rakesh,Khadilkar Satish 대한신경중재치료의학회 2020 Neurointervention Vol.15 No.3

Spinal dural arteriovenous fistulae (AVF) are rare and can result in spinal cord dysfunction. We present one such case wherein the patient presented with a venous congestive myelopathy. Magnetic resonance imaging showed a syrinx formation, spinal cord edema, and flow voids. Digital subtraction angiography confirmed the dural AVF, which was treated with embolization. The syrinx disappeared, other spinal cord changes improved, and the patient had remarkable clinical improvement. The case is presented to draw attention to the rare formation of a syrinx in a spinal dural arteriovenous fistula and its disappearance after successful embolization.

Fluorescent Properties of Daehwangjam, Golden Silk, and Juhwangjam and Their Diminishing upon HCl Vapor Exposure

Rakesh K. Jha,김성완,Sunghwan Kim 한국잠사학회 2024 International Journal of Industrial Entomology Vol.48 No.1

For over five millennia, humans have benefited from the valuable byproducts of Bombyx mori silkworms nourished on mulberry leaves and a multitude of potential applications remains available due to the diverse array of silkworm varieties. In this work, we discuss the utilization of Daehwangjam (DHJ), golden silk (GS), and Juhwangjam (JHJ), distinctive colored silks found in Korea, as chemosensors. These novel silks emit fluorescence under external stimuli and show a diminishing fluorescence intensity when exposed to HCl vapor. The considerable surface-to-volume ratio of these cocoons allows for the identification of 5 ppm, 300 ppm, and 3000 ppm HCl vapors through decreased fluorescence intensity. The results show the suitability of natural DHJ, GS, and JHJ for applications in biosensing applications.

In-situ braking torque and temperature analysis of two-wheeler drum brake in friction braking

Rakesh Kumar Singh,Chiranjit Sarkar 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.4

Generally, two-wheelers consist of a drum brake on the rear wheel. The performance of the brake deteriorates drastically due to the continuous use of brakes during driving. Thus, studying brake performance in the worst conditions, where brakes are applied back to back after a fixed time interval, becomes essential. To fulfill this, the in-situ braking torque behavior of the two-wheeler drum brake is studied experimentally, and the in-situ thermal behavior is studied experimentally and numerically in the present paper. A new test rig is designed using a motor, torque sensor, data acquisition system, and drum brake of the twowheeler. The effect of speed and braking cycles on the torque and thermal behavior of drum brake is studied. The torque required for approximately the same deceleration is dependent on the speed of drum and brake cycles. Similarly, results are found for thermal analysis, and drum surface temperature depends on the speed of the drum. Moreover, the drum surface temperature increases steadily with the increase of brake cycles.

Numerical modeling on the sensitivity of directional dependent interface heat transfer on thermal transport in a coupled fracture-matrix system

Rakesh Thekke Veettil,Govindarajan Suresh Kumar 한국지질과학협의회 2016 Geosciences Journal Vol.20 No.5

The conventional dual-porosity model has been modified by considering the heat exchange term at the fracture-matrix interface in the governing equation for thermal transport within the low permeable rock-matrix as against its conventional consideration within the high permeable fracture. A finite volume numerical model has been developed in order to analyze the influence of the source/sink term which defines the heat transfer at the fracturematrix interface. The comparison of the spatial distribution for temperature within the fracture and within the reservoir matrix for two different models, (1) conventional model in which the source/ sink heat transfer term included in the equation for thermal transport within the fracture; (2) proposed model in which the source/ sink heat transfer term included in the equation for thermal transport within the rock-matrix, have been performed. In addition, the sensitivity of the reservoir matrix thermal conductivities, both horizontal and vertical, on thermal energy extraction from the reservoir matrix has also been analyzed using the proposed model. Numerical results suggest that the estimation of temperature distribution in the fracture and rock-matrix and thus quantifying the heat extraction from the reservoir matrix is underestimated in a fracture-matrix system by using the conventional thermal transport model. It has been also observed that the temperature distribution obtained in the fracture and the rock-matrix by considering the heat transfer term in the thermal transport equation within the fracture shows significant variation from the temperature distribution obtained by considering the heat transfer term in the equation for thermal transport within the rock-matrix.

Modeling and flow analysis of piezoelectric based micropump with various shapes of microneedle

Rakesh Kumar Haldkar,Vijay Kumar Gupta,Tanuja Sheorey 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.6

Micropumps have been investigated as drug delivery and disease diagnostic devices. Many of these micropumps have been designed,considering primarily, available micro fabrication technologies rather than appropriate pump performance analysis. Piezoelectric andsilicon based micro pumps are more popular as compared to other smart materials being explored. The microneedle is an integral part ofthese micropumps providing an interface between the drug reservoir and the patient’s body for extracting the blood for investigation. Blood collected in the pump chamber passes through the biosensor and gives the required investigation report. It is aimed to minimize thepain while the microneedle is inserted in the body without having any effect on the flow characteristics. Several factors affect the painwhile inserting the needle, out of which shape and size of the microneedle are two important parameters. In this study we have investigatedthe effect of shape of the microneedle on the flow inside the micropump. A micropump design is based on the required flow at thebiosensor point. All computations were carried out with water (Newtonian fluid) as the working fluid after carrying out a comparativeanalysis with human blood (non-Newtonian fluid). For the pentagonal shaped microneedle, the velocity at the top of the microneedle wasminimum, which is beneficial in that fluid should remain in contact with the sensor for longer time.

Pull-out behaviour of recycled aggregate based self compacting concrete

Rakesh Siempu,Rathish Kumar Pancharathi 사단법인 한국계산역학회 2018 Computers and Concrete, An International Journal Vol.21 No.3

The use of recycled aggregate in concrete is gaining much attention due to the growing need for sustainability in construction. In the present study, Self Compacting Concrete (SCC) is made using both natural and recycled aggregate (crushed recycled concrete aggregate from building demolished waste) and performance of recycled aggregate based SCC for the bond behaviour of reinforcement is evaluated. The major factors that influence the bond like concrete compressive strength (Mix-A, B and C), diameter of bar (Db=10, 12 and 16 mm) and embedment length of bar (Ld=2.5Db, 5Db and full depth of specimen) are the parameters considered in the present study in addition to type of aggregates (natural and recycled aggregates). The mix proportions of Natural Aggregate SCC (NASCC) are arrived based on the specifications of IS 10262. The mix proportions also satisfy the guidelines of EFNARC. In case of Recycled Aggregate SCC (RASCC), both the natural coarse and fine aggregates are replaced 100% by volume with that of recycled aggregates. These mixes are also evaluated for fresh properties as per EFNARC. The hardened properties like compressive strength, split tensile strength and flexural strength are also determined. The pull-out test is conducted as per the specifications of IS 2770 (Part-1) for determining the bond strength of reinforcement. Bond stress versus slip curves were plotted and a typical comparison of RASCC is made with NASCC. The fracture energy i.e., area under the bond stress slip curve is determined. With the use of recycled aggregates, reduction in maximum bond stress is noticed whereas, the normalised maximum bond stress is higher in case of recycled aggregates. Based on the experimental results, regression analysis is conducted and an equation is proposed to predict the maximum bond stress of RASCC. The equation is in good agreement with the experimental results. The available models in the literature are made use to predict the maximum bond stress and compare the present results.

High Resolution Urban Air Quality Modeling by Coupling CFD and Mesoscale Models: a Review

Rakesh Kadaverugu,Asheesh Sharma,Chandrasekhar Matli,Rajesh Biniwale 한국기상학회 2019 Asia-Pacific Journal of Atmospheric Sciences Vol.55 No.4

According toWorld Health Organization, 9 out of 10 people breathe polluted air and the ambient air pollution accounts for nearly 4.2 million early deaths worldwide. There is an urgent need for scientific management of urban air systems. Mathematical modeling of air quality helps the researchers and urban authorities in devising scientific management plans for mitigation of the associated impacts.We present an organized review of the broad aspects related to urban air quality modeling such as – urban microclimate, geospatial data, chemical transport models, computational fluid dynamics (CFD) models and integration of CFD and mesoscale models. The paper also discusses about the influence of urban land scape features on air quality, accuracy of emission inventory and model validation methods. The present review provides a vantage point to the researchers in the emerging field of high resolution urban air quality modeling for devising the location specific mitigation plans for the scientific management of the clean air.

The incomplete generalized $\tau$-hypergeometric and second $\tau$-Appell functions

Rakesh Kumar Parmar,Ram Kishore Saxena 대한수학회 2016 대한수학회지 Vol.53 No.2

Motivated mainly by certain interesting recent extensions of the generalized hypergeometric function [\emph{Integral Transforms Spec. Funct.} 23 (2012), 659--683] and the second Appell function [\emph{Appl. Math. Comput.} 219 (2013), 8332--8337] by means of the incomplete Pochhammer symbols $ \left(\lambda; \kappa \right)_{\nu} $ and $ \left[\lambda; \kappa \right]_{\nu}$, we introduce here the family of the incomplete generalized $\tau$-hypergeometric functions $_{2}\gamma_{1}^{\tau}(z) $ and $ _{2}\Gamma_{1}^{\tau}(z) $. The main object of this paper is to study these extensions and investigate their several properties including, for example, their integral representations, derivative formulas, Euler-Beta transform and associated with certain fractional calculus operators. Further, we introduce and investigate the family of incomplete second $\tau$-Appell hypergeometric functions $\Gamma_{2}^{\tau_{1},\tau_{2}}$ and $\gamma_{2}^{\tau_{1},\tau_{2}}$ of two variables. Relevant connections of certain special cases of the main results presented here with some known identities are also pointed out.

COMMON FIXED POINT THEOREMS IN G-FUZZY METRIC SPACES WITH APPLICATIONS

Rakesh Tiwari,Shraddha Rajput 경남대학교 기초과학연구소 2021 Nonlinear Functional Analysis and Applications Vol.26 No.5

In this paper, we prove common fixed point theorems for six weakly compatible mappings in G-fuzzy metric spaces introduced by Sun and Yang [16] which is actually generalization of G-metric spaces. G-metric spaces coined by Mustafa and Sims [13]. The paper concerns our sustained efforts for the materialization of G-fuzzy metric spaces and their properties. We also exercise the concept of symmetric G-fuzzy metric space, φ-function and weakly compatible mappings. The results present in this paper generalize the well-known comparable results in the literature. We justify our results by suitable examples. Some applications are also given in support of our results.