ANovel Light Weight CNN Framework Integrated with Marine Predator Optimization for the Assessment of Tear Film-Lipid Layer Patterns

Tear film,the outermost layer of the eye,is a complex and dynamic structure responsible for tear production.The tear film lipid layer is a vital component of the tear film that provides a smooth optical surface for the cornea and wetting the ocular surface.Dry eye syndrome(DES)is a symptomatic disease caused by reduced tear production,poor tear quality,or excessive evaporation.Its diagnosis is a difficult task due to its multifactorial etiology.Out of several clinical tests available,the evaluation of the interference patterns of the tear film lipid layer forms a potential tool for DES diagnosis.An instrument known as Tearscope Plus allows the rapid assessment of the lipid layer.A grading scale composed of five categories is used to classify lipid layer patterns.The reported work proposes the design of an automatic system employing light weight convolutional neural networks(CNN)and nature inspired optimization techniques to assess the tear film lipid layer patterns by interpreting the images acquired with the Tearscope Plus.The designed framework achieves promising results compared with the existing state-of-the-art techniques.

Numerical Study on Application of CuO-Water Nanofluid in Automotive Diesel Engine Radiator

Application of CuO-water nanofluid with size of the nanoparticles of 20 nm and volume concentrations up 2% is numerically investigated in a radiator of Chevrolet Suburban diesel engine under turbulent flow conditions. The heat transfer relations between airflow and nanofluid coolant have been obtained to evaluate local convective and overall heat transfer coefficients and also pumping power for nanofluid flowing in the radiator with a given heat exchange capacity. In the present study, the effects of the automotive speed and Reynolds number of the nanofluid in the different volume concentrations on the radiator performance are also investigated. The results show that for CuO-water nanofluid at 2% volume concentration circulating through the flat tubes with Renf = 6000 while the automotive speed is 70 km/hr, the overall heat transfer coefficient and pumping power are approximately 10% and 23.8% more than that of base fluid for given conditions, respectively.

Computational Study on Aerodynamic and Thermal Characteristics of a Hot Jet in Parallel Flow

The study of the migration characteristics of turbulent jets has become relevant as they are used in a variety of engineering devices and are encountered in combustion, chemical processes, and processes involving cooling, mixing, and drying. In several applications, especially in the case of hot streaks in gas turbines, the knowledge of mixing phenomena becomes crucial from a design perspective. The purpose of this study is to look into the characteristics of a round hot jet in a parallel air flow. A jet of hot air injected through a nozzle into a flow of cold air has been considered. Numerical simulations were carried out with different hot jet temperatures and two different Reynold’s numbers, thus aiming at understanding the effect of initial conditions on the mixing of the jet. The temperature profiles were studied at different sections downstream of the nozzle. The results are presented in non-dimensional form.

A Chaotic Pulse Train Generator Based on Henon Map

The Henon map forms one of the most-studied two-dimensional discrete-time dynamical systems that exhibits chaotic behavior.The Henon map takes a point(Xn,Yn)in the plane and maps it to a new point(Xn+1,Yn+1).In this paper,a chaotic pulse generator based on the chaotic Henon map is proposed.It consists of a Henon map function subcircuit to realize the Henon map and another subcircuit to perform the iterative operation.The Henon map subcircuit comprises operational amplifiers,multipliers,delay elements and resistors,whereas,the iterative subcircuit is implemented with a simple design that comprises of an edge forming circuit followed by a monostable multivibrator and a voltage controlled switch without the use of any clock control.The proposed design can be used to realize the Henon map and also to generate a chaotic pulse train,with a controllable time interval and pulse position.The proposed circuit is implemented and simulated using Multisim 13.0 and MATLAB R2019b.The chaotic nature of the generated pulse train and also the time interval between the consecutive pulses is verified by the calculation of its Lyapunov exponents.

An Efficient 3D CNN Framework with Attention Mechanisms for Alzheimer’s Disease Classification

Neurodegeneration is the gradual deterioration and eventual death of brain cells,leading to progressive loss of structure and function of neurons in the brain and nervous system.Neurodegenerative disorders,such as Alzheimer’s,Huntington’s,Parkinson’s,amyotrophic lateral sclerosis,multiple system atrophy,and multiple sclerosis,are characterized by progressive deterioration of brain function,resulting in symptoms such as memory impairment,movement difficulties,and cognitive decline.Early diagnosis of these conditions is crucial to slowing down cell degeneration and reducing the severity of the diseases.Magnetic resonance imaging(MRI)is widely used by neurologists for diagnosing brain abnormalities.The majority of the research in this field focuses on processing the 2D images extracted from the 3D MRI volumetric scans for disease diagnosis.This might result in losing the volumetric information obtained from the whole brain MRI.To address this problem,a novel 3D-CNN architecture with an attention mechanism is proposed to classify whole-brain MRI images for Alzheimer’s disease(AD)detection.The 3D-CNN model uses channel and spatial attention mechanisms to extract relevant features and improve accuracy in identifying brain dysfunctions by focusing on specific regions of the brain.The pipeline takes pre-processed MRI volumetric scans as input,and the 3D-CNN model leverages both channel and spatial attention mechanisms to extract precise feature representations of the input MRI volume for accurate classification.The present study utilizes the publicly available Alzheimer’s disease Neuroimaging Initiative(ADNI)dataset,which has three image classes:Mild Cognitive Impairment(MCI),Cognitive Normal(CN),and AD affected.The proposed approach achieves an overall accuracy of 79%when classifying three classes and an average accuracy of 87%when identifying AD and the other two classes.The findings reveal that 3D-CNN models with an attention mechanism exhibit significantly higher classification performance compared to other models,highlighting the potential of deep learning algorithms to aid in the early detection and prediction of AD.

Stability Analysis of DC Microgrid Clusters Based on Step-by-step System Matrix Building Algorithm

DC microgrids(DCMGs)are made up of a network of sources and loads that are connected by a number of power electronic converters(PECs).The increase in the number of these PECs instigates major concerns in system stability.While interconnecting the microgrids to form a cluster,the system stability must be ensured.This paper proposes a novel stepby-step system matrix building(SMB)algorithm to update the system matrix of an existing DCMG cluster when a new microgrid is added to the cluster through a distribution line.The stability of the individual DCMGs and the DCMG cluster is analyzed using the eigenvalue method.Further,the particle swarm optimization(PSO)algorithm is used to retune the controller gains if the newly formed cluster is not stable.The simulation of the DCMG cluster is carried out in MATLAB/Simulink environment to test the proposed algorithm.The results are also validated using the OP4510 real-time simulator(RTS).

Special Column for the 9th Asian Joint Workshop on Thermophysics and Fluid Science 2022(AJWTF 2022)

This Special Column of Journal of Thermal Science(JTS)contains a selection of peer-reviewed papers from AJWTF 2022,held in Utsunomiya,Japan during 27 to 30November,2022.The Asian Joint Workshop and Thermophysics is a biennial international conference facilitating cooperation between scientists of Asian nations.The conference was founded by three renowned academicians Prof.Heuy Dong Kim,from South Korea,Prof.Shen YU from China and Prof.Toshiaki Setoguchi from Japan.The inaugural edition of the conference was held at Qufu,China in 2006.This was followed by Luoyang,China(2008),Matsue,Japan(2010),Busan,Korea(2012),Nagasaki,Japan(2014),Guilin,China(2016),Trivandrum,India(2018),Daegu,Korea(2020).The ninth edition of the conference,held at Utsunomiya,Japan in November,2022 was chaired by Prof.Makoto Yamamoto of the Department of Mechanical Engineering,Tokyo University of Science,Japan.The conference involved keynote lectures and talks from distinguished academicians and professionals from the industry.Progress made and future directions on research involving fluid and thermal sciences and engineering were part of the deliberations.The conference also provided an opportunity for cultural exchanges and promotion of soft power of participating nations.

Computational Study of Performance Characteristics for Truncated Conical Aerospike Nozzles

Aerospike nozzles are advanced rocket nozzles that can maintain its aerodynamic efficiency over a wide range of altitudes. It belongs to class of altitude compensating nozzles. A vehicle with an aerospike nozzle uses less fuel at low altitudes due to its altitude adaptability,where most missions have the greatest need for thrust. Aerospike nozzles are better suited to Single Stage to Orbit(SSTO) missions compared to conventional nozzles. In the current study, the flow through 20% and 40% aerospike nozzle is analyzed in detail using computational fluid dynamics technique. Steady state analysis with implicit formulation is carried out. Reynolds averaged Navier-Stokes equations are solved with the Spalart-Allmaras turbulence model. The results are compared with experimental results from previous work. The transition from open wake to closed wake happens in lower Nozzle Pressure Ratio for 20% as compared to 40% aerospike nozzle.

Mass Flow Prediction of the Coriolis Meter using C^0 Continuous Beam Elements

A three node C^0 continuous isoparametric beam element is formulated to model the curved pipe conveying fluid in three dimensional configuration.The equations of motion for the combined structure and fluid domain including added mass effect,Coriolis effect,centrifugal effect and the effect of pressure on the walls of pipe have been developed by Paidoussis.This equation is converted to finite element formulation using Galerkin technique and is validated with the results available from literature.

Computational Study on the Influence of Number of Threads on the Perfor-mance of Single Screw Pump at High Angular Velocities

Fluid flow in a screw pump which rotates at very high angular velocity is numerically analyzed. In the present study, fluid flow in screw pumps under high Reynolds number, of the order of 105, is considered. Screw pump has two major elements, a plain shroud which is a stationary element and a rotating hub with helical grooves contained within the shroud. In this paper, three variants of hubs with different number of thread starts numbering six, eight and twelve in combination with a plain shroud is studied. Each of the three possible combinations are analyzed on the basis of pressure rise developed, efficiency and shaft power. It was seen that pressure rise, efficiency and shaft power increases as the number of threads increases in the range of mass flow rates studied.

A Review on Challenges in DC Microgrid Planning and Implementation

DC microgrids are gaining more attention with the increased penetration of various DC sources such as solar photovoltaic systems, fuel cells, batteries, etc., and DC loads. Due to the rapid integration of these components into the existing power system, the importance of DC microgrids has reached a salient point. Compared with conventional AC systems, DC systems are free from synchronization issues, reactive power control, frequency control, etc., and are more reliable and efficient.However, many challenges need to be addressed for utilizing DC power to its full potential. The absence of natural current zero is a significant issue in protecting DC systems. In addition,the stability of the DC microgrid, which relies on inertia, needs to be considered during system design. Moreover, power quality and communication issues are also significant challenges in DC microgrids. This paper presents a review of various value streams of DC microgrids including architectures, protection schemes, power quality, inertia, communication, and economic operation. In addition, comparisons between different microgrid configurations, the state-of-the-art projects of DC microgrid, and future trends are also set forth for further studies.

Micro-synchrophasor based special protection scheme for distribution system automation in a smart city

Introduction:Aspects of power system protection which contributes to mal-operations and blackouts can be improved by supervision of system behavior and response based analysis rather than condition-based or event-based analysis using wide area measurements based on synchrophasor technology.The paper explores the application of micro-Phasor Measurement Unit for time synchronized real-time distribution network monitoring and agile decision support schemes for system prognosis and control.Case description:The scheme is proposed as part of a project on“Power System Voltage Stability Analysis using synchrophasors in Distribution System of Kerala Grid”at Kerala State Electricity Board Ltd.An actual grid occurrence during the severe tropical cyclone Ockhi,is considered as the base case which motivated the work.Discussion and evaluation:A voltage stability index(VSI)based special protection scheme(SPS)for radial distribution network at a proposed smart city is presented in the present study.The proposed special protection scheme on actual implementation can use data from proposed local micro-Phasor Measurement Unit.The PMU is proposed to be placed at one of the key nodes of the distribution system network in the city.Conclusion:The VSI is derived using local phasor values and is used to initiate a Special Protection Scheme for N-1 contingency at the key node,so as to ensure availability of the most essential feeder which provides supply to a hospital campus housing several health institutes of prime importance.The voltage stability index derived is tested and SPS is validated using real-time grid data.

Computational study on flow through truncated conical plug nozzle with base bleed

Conical plug nozzle and truncated conical plug nozzle are advanced rocket nozzles suitable for use as altitude compensating nozzles.In this study flow through the conical plug and truncated conical plug nozzles are numerically simulated to first validate with experimental data and then to compare the performance when a base bleed is introduced.The numerical analysis has considered two-dimensional axisymmetric models.Reynolds-averaged NavierStokes equations are solved with two equation shear stress transport k-ω turbulence model.For the validation of the plug nozzle,flow features and wall pressure along the length of the nozzle is taken for different nozzle pressure ratios.For the validation of truncated plug nozzle,flow features and base pressures at various nozzle pressure ratios are compared.The base bleed is taken as 2%of the inlet mass flow rate.The comparison of results shows that the introduction of base bleed helps to compensate for the loss of thrust due to conical plug nozzle truncation.

Laminar Forced Convection from a Rotating Horizontal Cylinder in Cross Flow

The influence of non-dimensional rotational velocity, flow Reynolds number and Prandtl number of the fluid on laminar forced convection from a rotating horizontal cylinder subject to constant heat flux boundary condition is numerically investigated. The numerical simulations have been conducted using commercial Computational Fluid Dynamics package CFX available in ANSYS Workbench 14. Results are presented for the non-dimensional rotational velocity α ranging from 0 to 4, flow Reynolds number from 25 to 40 and Prandtl number of the fluid from 0.7 to 5.4. The rotational effects results in reduction in heat transfer compared to heat transfer from stationary heated cylinder due to thickening of boundary layer as consequence of the rotation of the cylinder. Heat transfer rate increases with increase in Prandtl number of the fluid.