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

Laser powder bed fusion (LPBF) process is used for fabricating complex geometries of metallic parts ranging from macro to micro size. Fabrication of a part with various curvature angles is always a great challenge due to variation in the deposition of material at the curvature. The process parameters of contour exposure of the printing part play an important role in geometrical accuracy. Hence, In this study, the contour of various curvatures (30 ∘, 60 ∘, 90 ∘, &amp; 120 ∘) is analyzed for various laser power and scanning speed. It is found that track width at the curvature is increased from 17 % to 160 % on decreasing the angle between tracks from 120 ∘ to 30 ∘ compared to the width at the track. The variation in width at curvature and track is occurred due to an increase in supplied energy because of deceleration and acceleration of the laser source at the curvature. Further, the width at the curvature gets wider during the subsequent layer deposition and increases with linear energy density due to remelting and spreading at the curvatures. © 2023, The Author(s), under exclusive licence to Springer Nature Switzerland AG.

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Department of Mechanical Engineering

Progress in Additive Manufacturing

Study on track width of various curvature angles in laser powder bed fusion deposition

This paper presents a novel framework for a robust motion control scheme of an eight-thruster underwater vehicle. It combines a model-free approach intertwined with a model-based approach such as sliding mode control (SMC) to counter the unknown disturbances and decouple them to provide better tracking. A proportional-integral (PI) control-like structure is taken as the first sliding surface. A proportional derivative (PD) control-like structure is proposed as the second sliding surface for trajectory tracking. This motion control works for any fully actuated or over-actuated vehicle. Initially, the dynamic model and vehicle configuration are presented. Then the vehicle’s closed-loop behavior is studied in the presence of underwater currents. Later, the study considers external disturbances and compensates them with the help of a nonlinear disturbance observer. Lyapunov’s direct method and Barbalat’s lemma ensure the asymptotic convergence of tracking errors. The proposed controller performance is evaluated using a detailed comparison study with different model-free and model-based controllers from the literature. Later, the control scheme’s effectiveness is demonstrated numerically with the help of computer-based simulations. The robustness against the parameter uncertainties, underwater currents, and unknown disturbances is also presented. © 2023, The Author(s), under exclusive licence to Springer Nature B.V.

Journal of Intelligent and Robotic Systems: Theory and Applications

Robust Motion Control of Fully/Over-Actuated Underwater Vehicle Using Sliding Surfaces

Parallel kinematic machines (PKMs) whose moving platforms realises one-translational and two-axes rotation (1T2R) motion pattern, find a wide variety of applications. However, a majority of the 1T2R PKMs suffer from singularities and parasitic motions. Higher dexterity requirements further constrict its already limited workspace volume. This paper introduces a novel 1T2R parallel mechanism to address typical issues in dexterity, singularities, and parasitic motions. The mathematical modelling covers a comprehensive analytical inverse kinematics modelling. The analyses performed evaluate mobility, singularities, and dexterity of the mechanism. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.

Mechanisms and Machine Science

Conceptual Design and Kinematic Analysis of a 1T2R Parallel Manipulator

This paper presents a detailed design of a skid-steering mobile platform with four wheels, along with a Cartesian serial (PPP) manipulator. The aim of this design is to enable the platform to perform various tasks in the agricultural process. The parallel manipulator designed can handle heavy materials in the agricultural field. An experimental robotic harvesting scenario was conducted using parallel manipulator-based end-effectors to handle heavy fruits such as watermelon or muskmelon. The conceptual and component design of the different models was carried out using the Solidworks modeling package. Design specifications and parametric values were utilized during the manufacturing stage. The mobile manipulator was simulated on undulating terrain profiles using ADAMS software. The simulation was analyzed for a duration of 15 s, and graphs depicting the distance, velocity, and acceleration were evaluated over time. Proportional derivative control and proportional derivative-like conventional sliding surface control were applied to the model, and the results were analyzed to assess the error in relation to the input and desired variables. Additionally, a structural analysis was performed to ensure minimal deformation and the highest safety factor for the wheel shaft and L bracket thickness. Throughout the fabrication and prototype development, calibration tests were conducted at various X-, Y-, and Z-axis frame mounting stages. The objective was to minimize the lateral and longitudinal deviation between the parallel linear motion (LM) rails. Once the fabrication and prototype construction was completed, field testing was carried out. All mechanical movements in the lateral and longitudinal directions functioned according to the desired commands given by the Arduino Mega, controlled via a six-channel radio frequency (RF) controller. In the context of agriculture, the grippers utilizing parallel mechanisms were also subjected to testing, demonstrating their ability to handle sizable cylindrical and spherical fruits or vegetables, as well as other relevant objects. © 2023 by the authors.

Machines

Designing and Implementing a Versatile Agricultural Robot: A Vehicle Manipulator System for Efficient Multitasking in Farming Operations

Serotonin (5-hydroxytryptamine (5-HT)) is one of the important neurotransmitters which is released from the endocrine system. An abnormal level of this biomarker leads to several neurological diseases. The accurate assessment of serotonin is the utmost option to start treatment in the early stages of the disease. The current work is focused on the development of a disposable, screen-printed electrochemical sensor for the depression biomarker, serotonin in the physiological pH medium (pH 7.4) with the aid of a hexagonal, Ni(OH)2-nanoplate (NH-HNP)-embedded chitosan (Chit) and modified, screen-printed carbon electrode (SPCE). Initially, hexagonal nanoplates of Ni(OH)2 were synthesized by an eco-friendly and simple hydrothermal method. The prepared materials were well characterized by advanced analytical techniques to examine the physicochemical properties of the synthesized Ni(OH)2 hexagonal nanoplates. From the cyclic voltametric (CV) analysis, it was found that the oxidative current response of 5-HT at a NH-HNP-modified SPCE has about fivefold higher current values than over bare SPCE. The scan rate studies of NH-HNP-Chit/SPCE electrodes revealed that the oxidation mechanism of 5-HT is controlled by the diffusion behavior of the analyte. Differential pulse voltammetric tests of the NH-HNP-Chit/SPCE electrode exhibited a linear response in the dynamic concentration range of 0.1 to 30 µM, with a detection limit of about 60 nM. The sensor response is very reproducible from electrode to electrode, and the deactivation or surface-fouling of the sensor was not observed within the several experimental measurements. The sensor exhibited excellent storage stability over a period of twenty days. Finally, the fabricated, disposable SPCE sensor has shown respectable activity for the detection of depression biomarker 5-HT from synthetic urine and saliva samples. © 2023 by the authors.

Department of Chemistry

Fulltext

Micromachines

A Disposable Screen Printed Electrodes with Hexagonal Ni(OH)2 Nanoplates Embedded Chitosan Layer for the Detection of Depression Biomarker

Environmental toxic pollutants and pathogens that enter the ecosystem are major global issues. Detection of these toxic chemicals/pollutants and the diagnosis of a disease is a first step in efficiently controlling their contamination and spread, respectively. Various analytical techniques are available to detect and determine toxic chemicals/pathogens, including liquid chromatography, HPLC, mass spectroscopy, and enzyme-linked immunosorbent assays. However, these sensing strategies have some drawbacks such as tedious sample pretreatment and preparation, the requirement for skilled technicians, and dependence on large laboratory-based instruments. Alternatively, biosensors, especially paper-based sensors, could be used extensively and are a cost-effective alternative to conventional laboratory testing. They can improve accessibility to testing to identify chemicals and pollutants, especially in developing countries. Due to its low cost, abundance, easy disposal (by incineration, for example) and biocompatible nature, paper is considered a versatile material for the development of environmentally friendly electrochemical/optical (bio) sensor devices. This review presents an overview of sensing platforms constructed from paper, pointing out the main merits and demerits of paper-based sensing systems, their fabrication techniques, and the different optical/electrochemical detection techniques that they exploit. © 2023 by the authors.

Biosensors

Trends in Paper-Based Sensing Devices for Clinical and Environmental Monitoring

Metallogels formed from supramolecular interactions of low-molecular-weight gelators (LMWGs) combine the qualities of heterogeneous catalysts and offer the advantages of multifunctionality owing to the facile installation of desired task-specific moieties on the surface and along the channels of the gels. We discuss the applications of a triazole-based Ni(II) gel-derived xerogel (NiXero) having a high density of Ni(II)-nodes and appended primary amines as a recyclable heterogeneous catalyst for Knoevenagel condensation of aldehyde and malononitrile in water and the solvent-free cycloaddition of CO2 to form a series of cyclic carbonates with near-quantitative conversion of the respective epoxides, with low catalyst loading (0.59 mol %), high catalyst stability and recyclability. The structural advantages of NiXero, due to the concurrent presence of bifunctional Lewis acid-base sites on the channels, open Ni(II) nodes, Ntriazole, pendant −NH2 and its chemical stability, are conducive to the cooperative heterogeneous catalytic activity under mild conditions. This work emphasizes the effective amalgamation of metals with purpose-built ligand systems for the construction of metallogels and their utility as heterogeneous catalysts for desired organic transformations. © 2023 American Chemical Society

Inorganic Chemistry

Amine-rich Nickel(II)-Xerogel as a Highly Active Bifunctional Metallo-organo Catalyst for Aqueous Knoevenagel Condensation and Solvent-free CO2 Cycloaddition

The durability of concrete incorporating cactus extract as a bio-admixture is the focus of this study, which is the first of its kind in the literature. Cactus-infused concrete is a novel type of concrete with exceptional fluidity, strength, and durability. In this project, cactus was employed as an addition to M25(3626 psi) concrete, which was designed to Indian standards. Cactus extract (1\% to 9\% of the total weight) was used to replace the water in the mix. In order to look into the durability properties of cactus concrete, durability experiments such as drying shrinkage test, water absorption, porosity, sorptivity, accelerated carbonation, acid, and alkalinity tests were carried out on the material. ETC concrete enhances the fluidity of the mixture, making it more workable. To determine the particle distribution in concrete, scanning electron microscopy (SEM) was used to investigate the material. According to experimental research, polysaccharides and fats in concrete have increased their durability properties by 30\% when used at their optimal level. However, a high level of durability is attained, which encourages concrete voids to be effectively filled.

PERIODICA POLYTECHNICA-CIVIL ENGINEERING

Durability Evaluation of Cactus-infused M25 Grade Concrete as a Bio-admixture

Dual nickel-photoredox-enabled direct synthesis of amides through cross-coupling of cesium oxamates with aryl bromides has been developed. This methodology’s key advantages are mild reaction conditions, utilizing organic dye as a photocatalyst, employing readily available starting chemicals as coupling partners and late-stage carbamoylation of pharmaceutically relevant molecules. DFT studies suggested that the nickel catalytic cycle proceeds via a radical addition pathway prior to the oxidative insertion. © 2023 The Authors. Published by American Chemical Society.

ACS Organic and Inorganic Au

Redox-Neutral Decarboxylative Cross-Coupling of Oxamates with Aryl Bromides

Background: Adolescence and early adulthood are vulnerable periods for substance use-related disorders later in life. The use of internet-enabled interventions can be useful, especially in low-resource settings. Aims: To examine the feasibility, acceptability and preliminary effectiveness of single-session digital screening and brief intervention (d-SBI) for illicit drug misuse in college students and explore barriers and facilitators of d-SBI. Methods: Design: Mixed-methods, pilot cluster randomized trial. Setting: Four conveniently selected colleges were randomized into intervention and control groups. Participants: 219 students were screened and 37 fulfilled eligibility. Twenty-four completed follow-ups. In-depth interviews were done with ten students. Intervention and Comparator: Following a digital screening, Alcohol, Smoking and Substance Involvement Screening Test (ASSIST) based brief intervention was provided in the d-SBI group. The control group received brief education. Measurements: Acceptability was assessed by direct questions and usage statistics. ASSIST scores of groups were assessed at baseline and 3 months. Inductive coding of the interview transcript was done. Results: More than 50 % of participants found d-SBI user-friendly, appropriate and useful. Eighty percent of users, who logged in, completed screening. Per-protocol analysis showed a reduction in cannabis-ASSIST score over 3 months. The mean ASSIST score for other drugs combined did not differ significantly between groups. The difference in risk transition (moderate to low) was not significant. Qualitative analysis revealed three overarching themes- recruitment, engagement and behavior change. Conclusions: Digital SBI for drug misuse is feasible among college students. d-SBI might be effective in reducing cannabis use. © 2023 Elsevier B.V.