bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Study during Lockdown Period Based on AQI over Indian Mega cities during COVID-19
Authors: Chakraborty M , Debnath S , Ghosh S 
Published: March 2021

Abstract
The COVID-19, the most deadly challenge human being could have imagined, has become a reality now and the whole world is passing through the worst pandemic situation. From the challenges of invention of life saving vaccine or medicine to keeping economy at right track are the most talked about hurdles in front of all of us. But if we look at the other side of the coin, the blessings that came in form of disguise could be realised. The paper emphasizes on those aspects during lockdown that was imposed in India for three weeks initially that is 24th March to 14th April 2020 and later on till 3rd of May 2020. As a result of this forced restrictions, pollution level in whole India, specially in metro or mega cities where large population and pollution is a deadly combination, drastically changed. For analysing air quality, the metro-cities like Delhi, Kolkata, Chennai and Mumbai has been investigated here. The pollutant parameters PM2.5, SO2, NO2, along with CO, O3 and overall AQI (Air Quality index) has been collected and comparative study was done before and after lockdown and even for the year 2018 and 2019 too. Reduction of level of pollutants in significant amount of percentage is observed for all the metro cities where variation of reduction level from city to city is also significant. The effectiveness of lockdown over different metro cities are also very significant, pointing towards alertness of local people and population concentration. Finally, the study can be used in future as case study for controlling pollution with controlled lockdown and this can be practiced in future once or twice yearly to save our motherland.
Investigation of deep cryogenic treatment of Steels for medical tooling applications
Authors: Biswas P. , Ghosh S. , Sarkar A. , Roy N.G. 
Published: March 2021

Abstract
Hardened steels, which are resistant to corrosive chemical environments, are quite popular in the medical fields for various tooling applications exposed to low temperature. Using deep cryogenic treatments hardness and corrosion resistance of steel can be significantly improve for better compatibility of steels in biomedical applications. The present investigation examines the microstructure and evaluates hardness values of deep cryogenically heat treated AISI M2 steel. Studies on cryogenically treated tool steel show microstructural changes in the material can influence the life of the tools significantly. Through pertinent analyses of the experimental results this investigation infers that deep cryogenic treatment of AISI M2 steel increases the hardness of specimens marginally with the increase in the number of tempering cycle. The treatment further provides opportunity to exploit the possible use to hardened steels in robotic arms operative at low temperature research labs.
Influence of mobility, population and effective reproductive number (R) on the transmission of Coronavirus
Authors: Maithani Rajesh , Pandey Jitendra K , Kumar Anil 
Published: March 2021

Abstract
The present investigation reviews the potential causes of the novel Corona virus (COVID-19) spread based on various parameters studied. At the onset of COVID-19 pandemic there were number of parameters that were believed to be the dominating factor, and the demand of present scenario is to determine the potential variables that enhances the virus transmission. The social distancing is the main weapon to fight against the coronavirus, keeping this in mind the impact of mobility is analyzed. In addition to this the population density and the effect of temperature and humidity is studied on the present pandemic.
Educational Assistance Bot
Authors: Roy Arindam , Singh Dharmpal , Sahana Sudipta 
Published: March 2021

Abstract
An Internet bot performs automated tasks over the Internet. This software application is also known as a web robot or robot or simply bot, Typically, bots runs simple and structurally repetitive tasks, at a much higher rate than would be possible for a human alone. This effort is to help the users by providing all the basic student’s academic details like subjects, faculty names, books, notes and routine according to their need using bot. Users can also get other information like fees structure, library inventory list, calendar etc. Additional information like top educational sites, most trending educational videos etc will be regularly updated by the admin. This is an all-in-one application which can also be used to fetch and update information which is purely related to COVID-19.
A study on students’ responses on digital teaching methodology under covid-19 perspectives
Authors: Chowdhury Subhajit Basu , Mahapatra Shubankar 
Published: March 2021

Abstract
The whole world is facing unique Pandemic situation due to the outbreak of corona virus since last couple of months. There is a consistent situation of panic and fear everywhere. India too is facing same situation and amidst the prolonged phases of lockdown, everything seems to come to stand still. Economy is severely hit by this pandemic situation. Various Industrial sectors have either turned sick or closed down due to demand crunch and lacks of people are losing jobs, resulting unprecedented crisis in the society. In education sector too, there is paradigm shift in teaching and learning methodology. The students cannot attend traditional class room teaching due to close down of schools and colleges. In higher education too, online classes are going on and the college students have no options but to attend virtual mode of classes and face online examinations in many instances. The students’ community is altogether experiencing a new and non-familiar teaching and learning environment. This research paper was written based on the online survey of higher education students in few districts of West Bengal. The survey was undertaken to unearth the responses of the students’ community to this digital teaching methodology, which they are facing. The responses of students to this new and unfamiliar digital teaching and learning environment were shown in the findings section of this paper.
Estimation of flood-damaged cropland area using a convolutional neural network
Authors: Lazin Rehenuma , Shen Xinyi , Anagnostou Emmanouil 
Published: March 2021

Abstract
Flood damage to croplands poses a significant threat to global food security. Effective disaster management to cope with future climate change, especially extreme precipitation, requires a robust framework to estimate such damage. For this study, we develop a model based on a convolutional neural network to estimate the area (in acres) of cropland damaged by flooding at the county level. Then we demonstrate the model’s performance for the period 2008–2019 over corn and soybean fields in the midwestern United States, which suffer frequent damage from recurrent flooding. We fed the network with remote sensing images and weather fields and divide the growing season into two windows, the early season (May–June) and the late season (July–November) for better performance. The results show mean relative error within

±

25% and relative root mean square error within 35%–75% in majority of the counties for most years. Finally, we show that the model forced with meteorological variables alone can provide acceptable accuracy, which indicates it can be applied to forecasting crop damage area in the upcoming season or the studying of future climate impact on crop productivity. In principle, the model can also be applied to food security assessment at the global scale using available records.
Fatigue behaviour of thin Fe-Si steel sheets for electric motor production
Authors: Fortese G , Nicoletto G , Riva E 
Published: March 2021

Abstract
The on-going evolution toward electric/hybrid traction requires the development of high-performance electric motors. The rotor of electric motors is made from a stack of thin steel sheets and a complex configuration of magnets. Electric steels are typically Fe-Si alloys where Si addition controls grain size. Mechanical durability assessment of electric motors is based on the fatigue performance of Fe-Si steels.
This contribution reports a thorough mechanical characterisation of a Fe-Si alloy in the form of thin (i.e. 0.2 mm) sheets. Numerous tensile tests were performed to characterize the reference static properties and their respective scatter. A suitable fatigue testing procedure for thin sheets was developed and used in an extensive campaign aimed at investigating the directional fatigue behaviour of the Fe-Si steel. Comparison with literature data confirms that the fatigue response of thin sheets is affected by different factors related especially to the method of extraction.
Crack detections in fatigue loaded structures by means of low-cost Thermoelastic Stress Analysis setups
Authors: Cappello Riccardo , Catalanotti Giuseppe , Pitarresi Giuseppe 
Published: March 2021

Abstract
The work presents the results of an experimental evaluation of the thermoelastic signal on fatigue loaded single-edge-notched and tensile samples made of stainless steel. The thermographic signal is acquired by a micro-bolometer sensor Flir A655sc. The evaluation is performed varying the loading frequency and sampling frequency. The thermoelastic signal is evaluated by a Discrete Fourier Transform algorithm accounting for the influence of spectral leakage. Two different crack tip search algorithms are applied and compared: a grid method with pixel and sub-pixel accuracy and a sub-pixel pattern search method, both based on least square fitting of the Williams’ Series stress function. The two algorithms are also evaluated in terms of accuracy, automation level and computation timing. The SIF evaluated by the Micro-Bolometer is corrected by a specific camera dependent calibration procedure, and the influence of the number of points used in the least square fitting on the final value of the SIF is investigated in order to obtain the fastest and reliable setup conditions for an automatic full fatigue crack growth characterisation with a non-contact and low cost Infrared camera system.
Effects of FOD on fatigue strength of 7075-T6 hourglass specimens
Authors: Arcieri E V , Baragetti S , Lavella M 
Published: March 2021

Abstract
The term “Foreign Object Damage (FOD)” refers to the damage associated with the impact of particles on aircraft engine components that causes changes in fatigue strength as a result of induced stress concentrations, residual stresses and microstructural changes. This paper presents the Finite Element (FE) models created to study the stress field induced by the impacts of a steel sphere on a 7075-T6 hourglass specimen. The impacts occur at the minimum cross section, in the normal and oblique directions. The results reveal that in the event of an oblique impact the axial tensile stresses are greater and closer to the crater created by the impact. The superposition of the residual axial stresses to the bending stresses by fatigue test allows to identify the areas in which the maximum stresses are reached and therefore crack initiation is expected.
Fatigue behaviour assessment of C45 steel by means of energy-based methods
Authors: De Finis R , Palumbo D , Pirinu A , Saponaro A , Panella F W , Nobile R , Galietti U 
Published: March 2021

Abstract
Methods and techniques presented in literature for studying the fatigue behaviour of materials involve expensive, long lasting experimental campaigns and often a data analysis providing any information about damage localisation and occurrence. To avoid a time-consuming mechanical characterisation and to provide more information about where and when damage is occurring, the full-field experimental techniques such as infrared thermography allows the assessment of parameters that are related to the energy conversion to heat. In this work, the relationship between these thermal parameters (thermal methods) sentinels of the energy dissipated per cycle and the energy absorbed in every cycle is presented for the C45 steel undergoing stepwise loading fatigue tests.
Mechanical separation models for material recycling applications
Authors: Uggiosi D , Delogu M , Del Pero F , Berzi L 
Published: March 2021

Abstract
Mechanical recycling of common materials such as plastics requires appropriate material segregation, which is usually performed adopting processes similar to those developed for mineral engineering industry. Due to the need to increment amount and quality of selection products, such processes – still developed through trial-and-error approach – are also facing improvements in order to fit with the needs of different waste flows. The work here presented deals with methodologies for virtual and practical development of mechanical separation processes and, in particular, about the preliminary definition of densimetric tables devices; for this reason, a brief review on typical waste flow is provided. The case study considered is a mixed polymeric fragmented flow comprehending two main fraction (elastomer and rigid plastics), which have been subjected to a preliminary separation test. Due to the need to optimize the process, a model for material fluidization is proposed to investigate the relevance of process parameters (e.g. air speed value) depending on material bed characteristics. After this, an image processing tool for the rapid analysis of fragments has been prepared, its scope being to find out typical shape and size characteristics, needed as input to the model, and color identification and number, which can be used for output characterization and performance analysis. Model and image processing tool together constitute the basis for process redesign, optimization and verification.
Confidence intervals for the expected damage in random loadings: Application to measured time-history records from a Mountain-bike
Authors: Marques J M E 
Published: March 2021

Abstract
The fatigue damage of a structure is usually estimated by calculating the damage values of a limited number of measured random time-histories. The limited damage values are generally not identical due to the sampling variability. In a recent work, confidence interval expressions have been proposed to bound the expected damage value. The method revealed a good agreement with simulations, thus suggesting its use also with real measurements. The present paper investigates the above-mentioned confidence intervals for expected damage by a real engineering application, in which few measured time-history records, or even only one, are available. This goal is achieved after measuring the random loadings acting on an instrumented Mountain-bike riding in a typical north Italian off-road track. As the whole ensemble of an infinite number of time-histories is not available and the expected damage is thus not known a priori, a sort of calibrator sample damage value, which is computed using a large number of measured time-history records, is used to estimate the expected damage. The obtained results confirm the accuracy of the proposed approach also with real measurements.
CubeSat Spatial Expedition: An Overview From Design To Experimental Verification
Authors: Morettini G , Zucca G , Braccesi C , Cianetti F , Dionigi M 
Published: March 2021

Abstract
Over the past two decades, government space organizations have provided university-level inexpensive access to space that has prompted the design of miniaturized versions satellites for research scope: the ”CubeSats”. If on one hand, the standard specifications of this pico-satellite are widely defined to provide easy access to space for educational and research institutions, on the other hand, the design phases of the mechanical and electronic structures are however a very complex and delicate moment of fundamental importance for the success of the launch. The purpose of this document is to provide an exhaustive and critical picture, derived from a broad and in-depth literary analysis of all the critical phases to be faced in order to structurally verify a CubeSat 1U. Starting from the design phase, passing through the simulation and construction of the nano-satellite up to the effective execution of the experimental tests. The aim is to define a linear and efficient path underlining the possible errors and critical moments of the structural verification of a CubeSat.
An Experimental-Numerical Study on Curling Process for Metallic Caps Production
Authors: Bruno M , Bertocco A , Perrella M , Esposito L 
Published: March 2021

Abstract
In the field of food industry, adoption of metallic caps for the storage of agri-food products is widespread. This type of caps is obtained through a sequence of forming processes executed on a tinplate. First, the plane metal sheet is deep drawn to obtain a cup whose edge is slightly shaped inward, then a curling process forms the edge into a hollow ring. This paper is focused on the curling, which allows to assess the final cap shape immediately before the application of the cups on the jars. Since the process is generally made on packaging lines with high production rates, the design of a proper curling machine needs to consider the effect of fatigue as well as maximum load values. Because of the different cap dimensions and shapes contemporary worked on the line, the loads definition is not easy. The scope of this work is the development of a model for the prediction of curling loads for different cap shapes and sizes. The analytical solutions, available in literature, together with numerical simulations of the process were compared to experimental compression tests made on two different caps type. Considerations on caps geometry and size influence on curling force represent a contribution to the fitness for service evaluation as well as a starting point for the design of new curling machines.
Integration of nylon electrospun nanofibers into structural epoxy adhesive joints
Authors: Minosi S , Cocchi D , Pirondi A , Zucchelli A , Campanini F 
Published: March 2021

Abstract
The fracture toughness is a key parameter in the development of bonded joints for several structural applications. Adhesives are commonly toughened with fillers or modifying the resin chemical composition. Many studies also suggest that resin toughening could be achieved through electrospun polymer nanomat. In previous works, the Authors proved that nylon nanomats can be used as an adhesive carrier and reinforcing web for the adhesive layer. This allowed developing a laboratory route to produce high-quality prepregs of electrospun nylon carrier using medium viscosity, two-component, unfilled epoxy adhesive. By applying the same methodology, in the present work, electrospun nylon prepregs were produced using a high strength and high toughness 2k structural epoxy adhesive to toughen the joint. The wet nano-reinforced strips were placed between S235 steel sandblasted adherents and oven-cured to obtain Double Cantilever Beam (DCB) joints. DCB tests have been performed to compare the mode-I fracture toughness with and without the nanofibrous mat. Unlike previous works with medium-low toughness epoxies, this time the fracture toughness is reduced after the integration of an electrospun nano-reinforcement. From the Scanning Electron Microscope (SEM) images it seems that the nanomat hinders the ductile failure mechanism which instead develops in the neat resin.
Design of non-conventional biaxial tensile-shear tests for the structural characterization and ductile damage assessment of ductile engineering materials
Authors: Nalli F , Imbimbo B , Cortese L 
Published: March 2021

Abstract
The paper focuses on the development and optimization of a non-conventional specimen geometry for mechanical testing of ductile materials under shear-tension loading conditions. This is of major importance, being well known from literature works, that material final failure is strongly dependent on the stress state and that the information about the material ultimate resistance is crucial in virtually any kind of machine design related safety assessment. More in detail, in this study an effective way to load the samples with a combination of shear and tension is devised, selecting and optimizing a proper specimen geometry and designing the related gripping system. The goal is to obtain stress states in test runs different as much as possible one with the other, with specimens easy to be machined, and using just a standard universal testing machine. This would make the biaxial tests available to a broad group of end users, even industrial.
The state of the art of specimens for biaxial tests available in literature was used as starting point to design a novel simplified geometry and the dedicated gripping system. Numerical simulations of the prospective biaxial experiments were performed, ranging from pure shear to pure tension, to optimize the new geometry, improve its effectiveness and evaluate the material stress states and strain to fracture at the critical points that can be obtained from the tests. This local information proved to be sufficient to calibrate different damage models using the single proposed test, with proper combinations of shear to tension loads.
Different infill geometry influence on mechanical properties of FDM produced PLA
Authors: Bergonzi L , Vettori M , Stefanini L , D’Alcamo L 
Published: March 2021

Abstract
Fused Deposition Modelling (FDM) is one of the most widespread additive manufacturing technologies due to its relatively low cost and simplicity. Usually, printed parts have an internal structure (infill) that is not produced with 100% material density. This strategy is adopted to save material and time thanks also to the fact that when a component is loaded, stress are concentrated on its skin rather than in the internal section. Furthermore, infill structure can have different densities and topology. Slicer software have various configurations that can be exploited to produce internal structures: according to All3DP [1], some are intended for functional parts while others are more indicated to prototypes only. Aim of this work, is to compare the effect of different infill topologies produced using Ultimaker CURA [2] slicing software on material mechanical properties. Preliminary experimental activity has been carried out in order to determine the most suitable printing temperature. MaCh3D, an innovative miniaturized universal testing machine [3] was used to perform uniaxial tensile tests. Results underline the difference between different kind of infill in term of mechanical properties, given the same infill density across all specimens. Additionally, in order to evaluate infill percentage effect on mechanical properties, some of the most performing infill from the characterisation activity have been selected and specimens produced with 20%, 50%, 80% infill percentage. In the end, both infill topology as well as density impacts on mechanical properties.
Development and calibration of a structural simulation method of CF-SMC composite parts processed by compression molding
Authors: Delvò M , Nicoletto G , Riva E 
Published: March 2021

Abstract
The need for the reduction in CO2 production in automotive field increasingly leads manufacturers to consider fiber-reinforced composite materials that are however costly to processes. Discontinuous fiber composite materials, like CF - SMC, are a competitive candidate because they are transformed by the high productivity compression molding technology. On the negative side, their structural complexity introduces high variability in the mechanical performance that needs to be considered at the design stage. This contribution describes the development of a structural modeling strategy for parts made of CF-SMC processed by compression molding. It is based the statistical material model proposed by Feraboli implemented here in a FEA-based structural analysis procedure. After validation and calibration of a specific CF-SMC material, the proposed procedure is applied to the simulation of the structural response of a compression molded part of complex geometry subjected to know loading conditions.