Indian Institute of Technology Palakkad&nbsp;(IIT Palakkad or IIT PKD) is a public autonomous&nbsp;engineering&nbsp;and&nbsp;research&nbsp;institute located in&nbsp;Palakkad,&nbsp;Kerala. It was&nbsp;one of the five new&nbsp;IITs&nbsp;proposed in the&nbsp;2014 Union budget of India. The campus was inaugurated on 3 August 2015. The institute has 94 faculty, 978 students, and 63 non-teaching staffs.

IT Palakkad currently offers four-year Bachelor of Technology (B.Tech) and two years MS programmes in 8 different engineering disciplines including&nbsp;Computer Science, Electrical, Mechanical, Civil among others.

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IIT Palakkad

The paper presents the method of optimal geometric parameters synthesis for a robotic rehabilitation system of the lower limbs as based on a passive orthosis in the form of a serial RRRR mechanism and an active parallel 3-PRRR mechanism. A mathematical model of the kinematics of the RRRR mechanism is formulated. A numerical method is worked out for determining the workspace of the RRRR mechanism. The workspace description is based on the approximation of many solutions of systems of nonlinear inequalities to provide the required rotation angle of rotation in the joints. Effective numerical methods and algorithms are developed and tested. The paves the way for determining the minimum geometric parameters of an active parallel mechanism that ensure movements of a passive orthosis within the workspace under clinical data constrains when simulating walking. In order to implement the developed methods, an effective algorithm, software package and visualization system are synthesized for exported three-dimensional workspaces in STL. © 2021, Springer Nature Switzerland AG.

World University root node

Department of Mechanical Engineering

Communications in Computer and Information Science

The Method of Optimal Geometric Parameters Synthesis of Two Mechanisms in the Rehabilitation System on Account of Relative Position

Unstable machining conditions during wire EDM process can lead to process failures, which affects the efficiency and sustainability of process. The study aims to develop a sensor-based failure prediction and process control system. The monitoring system consisting of high sampling rate differential and current probes extracts voltage and current signals during spark machining. Relevant discharge characteristics like pulse proportions, pulse frequency, and discharge energy are extracted from the pulse train data. The proposed process control algorithm works in three stages: failure prediction, failure severity assessment, and process control. Failure conditions considered are wire breakage and spark absence, which are predicted based on the extracted discharge characteristics. Severity of failure is judged based on the spark discharge energy. The proposed process control algorithm retunes the process parameters by adjusting pulse on time, pulse off time, and servo voltage, based on the type of failure and its severity. The methodology is successful in preventing the potential failure situation by restoring the machining stability. The capability of the model is demonstrated by conducting confirmation experiments. Microstructural comparison of machined surfaces and worn wire surfaces also confirms the effectiveness of the proposed strategy to ensure failure free machining with better surface integrity. © 2021 CIRP

CIRP Journal of Manufacturing Science and Technology

Failure detection and control for wire EDM process using multiple sensors

In the recent past, intervention-class autonomous underwater vehicles (AUVs) have gained the ocean/marine research community's attention due to their multidisciplinary operational capabilities. This article discusses a detailed comparative-performance study of an underwater vehicle (UV) with two different actuator configurations based on fixed-thrusters and vectored thrusters. The fixed-thruster configuration consists of eight thrusters. Four thrusters generate thrust in the horizontal plane and the remaining thrusters produce thrust in heave direction. The vectored thruster configuration has four thrusters placed at diagonal corners of a rectangular vehicle, and four independent internal servomotors rotate these thrusters. The classification terminology in this article identifies the underwater vehicle without vectoring capability as Fixed-Thruster Underwater Vehicle (FTUV) and the one with vectoring capability as Vectored-Thruster Underwater Vehicle (VTUV). Furthermore, a nonlinear controller is designed, based on a backstepping scheme for tracking a given spatial profile in a three-dimensional space. An underwater robot's control for a trajectory tracking problem is useful for any real-time multidisciplinary autonomous applications. The comparative simulation results are summarized to validate both the vehicle variants’ performance differences. © 2021 Elsevier Ltd

Ocean Engineering

Simulation-based semi-empirical comparative study of fixed and vectored thruster configurations for an underwater vehicle

The frequency of rainfall-triggered landslides is increasing across the world. Infiltration of rainwater into the slopes with low permeable soil increases the pore water pressure and reduces the stability of slopes. Also, in the recent past, Kerala experienced many rainfall-triggered landslides. One of the most efficient way to prevent rainfall-triggered landslides would be the usage of composite geosynthetics which can combine the functions of pore pressure dissipation and reinforcements. In the present study, soil is collected from a nearby site where landslide has occurred and the geotechnical characterisation of the soil was carried out. An attempt was made to investigate the performance of steep soil slopes with and without the geosynthetics when subjected to rainfall, numerically. The study highlights the importance of the use of a composite geogrid in reinforced soil slopes composed of locally available marginal soil. © 2021, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

Department of Civil Engineering

Lecture Notes in Civil Engineering

Performance of Geosynthetic Reinforced Steep Soil Slopes at the Onset of Rainfall Infiltration

The current work aims to improve the sustainability of wire electric discharge machining by predicting the wire breakages. Wire breakages are process interruptions which increase the machining time, energy wastage and material consumption. The study is a novel approach to predict process continuity by binomial classification of machining outcomes using kernel-based naive Bayes algorithm. The two classes are labelled as wire breakages and continuous machining. Training dataset consists of 31 experiments according to central composite design of response surface methodology, and wire breakage instances are recorded as response. The input dataset contains four machining parameters, namely pulse on time, pulse off time, servo voltage and wire feed rate, whereas mean gap voltage variation is derived from in-process data. The trained model was 96.7% accurate in wire breakage predictions. Further, nine confirmation tests were conducted to check model adequacy in real-world situations. The model predicted all instances of wire breakages accurately. The stages of wire wear up to wire rupture were studied by conducting microstructural analysis. © 2021, The Brazilian Society of Mechanical Sciences and Engineering.

Journal of the Brazilian Society of Mechanical Sciences and Engineering

Sustainability improvement of WEDM process by analysing and classifying wire rupture using kernel-based naive Bayes classifier

We analyse the structure of finite dimensional subspaces of the set of points of strong subdifferentiability in a dual space. In a dual L1(μ) space, such a subspace is in the discrete part of the Yoshida-Hewitt type decomposition. In this set up, any Banach space consisting of points of strong subdifferentiability is necessarily finite dimensional. Our results also lead to streamlined and new proofs of results from the study of strong proximinality for subspaces of finite co-dimension in a Banach space. © 2021 Heldermann Verlag.

Department of Mathematics

Journal of Convex Analysis

Structure of sets of strong subdifferentiability in dual L1-spaces

The current paper presents a perturbation-based stochastic eigenvalue buckling analysis of thin plates using element free Galerkin method. Spatial variation in Young's modulus is modeled as a homogeneous random field and moving least square-based shape function method is employed for discretizing the random field. Perturbation method is used to evaluate the statistics of buckling loads. Numerical examples wherein rectangular plates with different boundary conditions are solved and the statistics obtained are compared with those calculated using Monte Carlo simulation. Different parametric studies are also conducted. The results obtained from perturbation method are found to be reasonably accurate for coefficient of variation (CV) values less than 20% for random fields with normal distribution. Further it is observed that for random fields with lognormal distribution, the proposed method produces reasonably accurate results up to a CV of 30%. © 2021 World Scientific Publishing Company.

International Journal of Computational Methods

Perturbation-Based Stochastic Meshless Method for Buckling Analysis of Plates

In this study, element-free Galerkin method (EFGM), a meshless method, is proposed for wrinkling analysis of pre-stressed rectangular membranes. The mathematical model for studying wrinkling of pre-stressed membranes is derived by considering the bending stiffness, though it is negligible. Moving least-square approximation for deflection is constructed by considering three degrees of freedom per node. Essential boundary conditions are imposed using scaled transformation matrix method. Initially, compression-induced buckling of a homogeneous thin plate without pre-stress is solved to validate the method and then a pre-stressed homogeneous membrane is analyzed for both compression-induced and shear-induced wrinkling. Capabilities of the proposed method for membrane analysis are compared with that of the finite element method (FEM). Comparative study on wrinkling analysis using EFGM and different FEM element types in a commercial FEM package shows that in lower modes both methods show satisfying consistency in eigenvalues with respect to the total of number of nodes, while at higher modes EFGM shows better consistency than FEM. Further, the study is extended to wrinkling of nonhomogeneous membranes subjected to linearly-varying in-plane load. The results obtained from EFGM analysis is compared and found to be matching well with those available in the literature. © 2021 World Scientific Publishing Company.

Wrinkling Analysis of Pre-Stressed Rectangular Membranes Using Element-Free Galerkin Method

Background: Sudden alcohol prohibition in India during the COVID-19 pandemic presented an opportunity to test whether Google Trends data could indicate population responses and the public health impact of alcohol policy. We hypothesized, following prohibition: there would be a significant change in the relative search volumes (RSV) of alcohol-related queries; that temporal analysis of the trends would reflect a public response to policy changes; and that geospatial analysis of RSV would correlate with the prevalence of alcohol use. Methods: Three different search periods were used to test the hypotheses. The search inputs were based on potential public response to alcohol prohibition, as evidenced by the literature, newspaper articles and consensus. We used RSV as the unit of analysis. Mean RSV of search queries, pre-post implementation of prohibition, were compared. Smoothing of scatter plots examined the temporal association of trends with policy measures. Multiple linear regression tested the relationship of state-wise RSV and alcohol use prevalence. Results: Post-implementation of prohibition, a significant increase in the RSV was observed for searches related to alcohol withdrawal (p<0.001), how to extract alcohol from sanitizer (p = 0.002), alcohol home delivery online (p<0.001), alcohol home delivery (p<0.001) and sleeping pills (p = 0.006). The trends suggested a decrease in general interest in alcohol but increased demand and a possible connection with changes in policy measures. State-level RSV and alcohol use prevalence did not reveal a significant relationship. Conclusion: Google trend is a potential source of rapid feedback to policymakers about population responses to an abrupt change in alcohol policies.

Department of Data Science

International Journal of Drug Policy

Can google trends search inform us about the population response and public health impact of abrupt change in alcohol policy? — a case study from india during the covid-19 pandemic

Abstract: Mathematical models are among the new approaches employed to predict the properties of any material under various conditions. Mathematical models are essential for not only understanding the material properties but also estimating the cost of design, product life, and failure criteria of the product. Therefore, in the current investigation, the hot deformation (HD) behaviour and microstructure alteration of deformed AA7150-5 wt% B4C composite was studied through a mathematical model. The new AA7150-5 wt% B4C composite was fabricated through an ultrasonic-probe assisted (20 KHz, 1000 W) stir casting process. The hot compression test was performed on a hydraulic press for various deformation temperatures (623–773 K) and strain rates (0.01–1 s− 1). Based on the outcome, it is inferred that the flow stresses and microstructures of AA7150-5 wt% B4C composite was significantly altered during the hot compression test under various deformation conditions. The constitutive and dynamically recrystallized grain (DRXed) models were developed as a function of various deformation conditions of deformed AA7150-5 wt% B4C composite, which was then applied to forecast the flow stress and grain size behaviour for different deformation conditions. The flow stress and DRXed grain size were obtained through the proposed constitutive and DRXed models are correlated with experimental results, with excellent accuracy. The models developed are reliable to predict the AA7150-5 wt% B4C properties for various conditions. Graphic abstract: [Figure not available: see fulltext.]. © 2021, The Korean Institute of Metals and Materials.

Metals and Materials International

Mathematical Models to Predict Flow Stress and Dynamically Recrystallized Grain Size of Deformed AA7150-5 wt% B4C Composite Fabricated Using Ultrasonic-Probe Assisted Stir Casting Process