bluuebunny/crossref_metadata_2025 huggingface dataset:
On the performance of Super Abrasive Machining (SAM) on small diameter cBN wheel wear
Authors: Bravo H , Ortega N , Polvorosa R , Zamakona I
Published: October 2021

Electroplated cBN wheels have increased their importance in industry, mainly in camshaft, crankshaft and gearbox grinding in the automotive sector and in grinding of aeronautical turbine parts made from nickel superalloys. Possible new applications include Integrated Blade Rotors (IBRs), whose importance is increasing in new aeroengine configurations. Electroplated cBN wheels form retention without trueing or dressing and low wear make them suitable for this usage. However, few information is available about wear and resulting surface finish characteristics in the small diameter wheels needed for this application. In this study, data about wheel topography and wear and surface finishing of resulting surfaces is shown. Also, some hypothesis about the reasons for the higher-than-expected resulting surface finish are exposed.
Resin Bonded Diamond grinding wheels conditioning using SiC rotary dresser
Authors: Muñoz A , Godino L , Sánchez J A , Pombo I , Tolosa I
Published: October 2021

Superabrasive grinding of advanced materials parts with complex geometry is a critical issue for aerospace or energy industry. Likewise, conditioning of superabrasive is a key process in order to obtain the most effective grinding. While from industrial point of view the conditioning parameters and dressers are designed from the experience, from scientific point of view the last works are focused on achieving guidelines for optimising conditioning process. In this sense, the present work is focussed on the conditioning process of diamond resin bonded grinding wheels. To this end, SiC rotary dressers of different hardness and applying down-cut and up-cut are tested in order to achieve the best conditions. On the one hand, the wheel surface is deeply analyse. A software is developed in order to analyse the grain pull out, the new abrasive grains and the size evolution and grain concentration during conditioning. On the other hand, the wheel geometry is also measured due to the importance of geometry loss during the conditioning process on profile grinding wheels. The results shown that down-cut conditions are more aggressive obtaining a better wheel surface recovery and the wheel geometry of the incidence edge is lost, requiring a subsequent truing process to obtain the wheel profile. Finally, it is noteworthy that the methodology developed for the analysis of the diamond resin bonded grinding wheels is suitable for all types of grinding wheels even rotary dressers.
Experimental application of a laboratory equipment for micro-electroforming using models manufactured with additive technology
Authors: Sánchez C J , Martínez M D , Hernández P M , Marrero M D , Salguero J
Published: October 2021

One of the manufacturing processes applications on a microscopic scale, consists in modifying parts or components´ surfaces to improve their properties. Unconventional machining processes are needed to generate complex geometries, high details reproduction, and excellent finished surfaces at that scale. Micro sinker electrical discharge manufacturing (μ-SEDM) process could be one good option. The electrode manufacturing is one of the main drawbacks. It supposes a big resources waste before starting to manufacture. In this way, working on a microscopic scale becomes a challenge to obtain different shapes and textures on functional surfaces. In this work, combined use of micro-electroforming and digital light processing (DLP) additive manufacturing is presented. These two additive techniques are completely different and unrelated in their applications, materials, and technological fundamentals. However, their combination is a low-cost option to obtain good results in the manufacture of μ-SEDM electrodes. Therefore, it was necessary to develop a micro-electroforming equipment to meet the challenge. Furthermore, device had to have the ability to adapt the process parameters to the needs of the parts. As a result of this experimental application, we got high-quality parts, which could have an industrial application.
Manufacture of an abrasive jet machining (AJM) equipment adapted for the treatment of rotary flexion fatigue specimens
Authors: Herrera M , Bermudo C , Trujillo F J , Martín S , Sevilla L
Published: October 2021

The influence of micro-geometric irregularities on fatigue strength and, in particular, surface topography is widely accepted. The different machining processes generate surface roughness on machined parts that may significantly modify their fatigue behaviour and compromise their use in components where structural stability is required. Therefore, the study of these materials behaviour under cyclic loading stresses becomes highly relevant. The aim of this work is to design and manufacture an abrasive jet machining machine, in order to improve the surface roughness in the dry turning of aluminium alloys for a study of the influence on fatigue life after modification of its surface topography, using similar parameters to any equivalent industrial equipment. For this purpose, several components from obsolete machines belonging to the Manufacturing Engineering Department of the University of Malaga have been reused, to reduce the final cost. Several tests have been carried out with the aim of testing the manufactured equipment. The experimental data have shown results in line with those offered by others in industrial use for similar abrasives and processing material. The equipment has been built in accordance with the ISO 12100:2010 Safety of machinery - General principles for design - Risk assessment and risk reduction.
Recent advances in the extrusion methods for ceramics
Authors: Buj I , Vidal D , Tejo A , Fenollosa F , Mesbahi J El , Mesbahi A El
Published: October 2021

In recent years, extrusion 3D printing processes have undergone an important development. They allow obtaining complex shapes in an easy way and relatively low cost. Different plastic materials can be 3D printed with the fused filament fabrication (FFF) technology. Bioinert ceramics such as alumina or zirconia have excellent physical and mechanical properties (high melting point, high strength…) that make them appropriate in different fields: medicine, electronics, etc. However, 3D printing of ceramics is by far less developed than 3D printing of plastics or metals. A possible application for 3D printing of ceramics is the manufacture of prostheses, which usually have complex shapes with porous structures. Ceramic prostheses have several advantages over the use of other materials: they generate low debris, they are hard and they are inert and corrosion-resistant. In the present work the recent advances about extrusion 3D printing of ceramic materials are presented, with a special focus on the manufacture of prostheses.
Study for the selection of 3D printing parameters for the design of TPU products
Authors: Rodríguez L , Naya G , Bienvenido R
Published: October 2021

The design and development of elastic products for additive manufacturing has the particularity that the manufacturing parameters can affect the aesthetic and functional properties due to the flexible nature of the material. Therefore, the selection of each of them should not be analysed separately. For this reason, in this work, different printing parameters were explored sequentially, observing their influence on the final finish obtained with the aim of adjusting the appropriate values to provide valid prototypes and products. Layer height, wall thickness, followability, extrusion temperature, shrinkage and printing speeds were studied. As a result, the parameters that offer the best results, with respect to the quality of finish, in 3D printing of TPU for application to the design of elastic products were determined.
Study of the influence of laser energy density on the surface roughness of Scalmalloy® samples manufactured by DMLS technology
Authors: Márquez C , López J D , Cabrera L , González L , Botana J
Published: October 2021

Direct Metal Laser Sintering (DMLS) is an additive metal manufacturing technology that allows complex parts to be built without the design constraints of conventional technologies. In addition, the possibility of reusing powder reduces raw material consumption and the amount of waste generated. However, one of the disadvantages of this technology is that, in most cases, it requires post-processing tasks that increase manufacturing costs and delivery times. Some of these additional tasks are aimed at reducing the surface roughness of the parts obtained, using technologies such as grinding, mechanical polishing, shot blasting or electropolishing. This work proposes to improve the surface quality of parts manufactured by DMLS by controlling the processing parameters. In this way, the costs associated with these post-processing tasks could be reduced. Specifically, it is proposed to study the effect of the laser energy density applied to the surface of the parts during the manufacturing process on their surface quality. To carry out this study, powders of the Al-Mg-Sc alloy known as Scalmalloy®, developed to manufacture parts by means of DMLS with application in the aeronautical sector, have been used. In this sector, surface quality is one of the factors limiting the implementation of DMLS technology for the manufacture of parts considered critical.
Evaluation of porosity in 3D printed trabecular bone structures for prostheses
Authors: Buj I , Bagheri A , Ferrer M , Domínguez A
Published: October 2021

Hip prostheses require an external porous area in order to fix them by means of osseointegration. Different structures can be printed in order to favour bone fixation, such as octet-truss or trabecular, among others. In the present paper, bone-like structures are printed in cubic shapes, by means of fused filament fabrication (FFF). Three design parameters of the structures were varied: the number of joining points per unit volume, the area scale and the offset that is given to the different struts of the structure. Both the theoretical and the measured porosity of the samples is evaluated, from the drawing of the structures and by means of weight measurements respectively. As expected, the structures having fewer union points per unit volume are more porous than the structures having more points. When low number of points generating struts of the structure were employed, measured porosity is lower than the theoretical one, while when high number of points is considered, the opposite situation is found. The present work will help to obtain porous structures to be used in prostheses, by means of extrusion 3D printing processes.
Barriers to Lean and Pull System implementation: a case study
Authors: Araújo A , Alves A C , Romero F
Published: October 2021

Lean Production has been documented in the last decades as a management methodology that brings many benefits. Nevertheless, many companies faced difficulties in implementing it and in having success. This happens due to the existence of some barriers to its implementation. This fact also occurs in the multinational company studied in this paper. Applying a case study methodology, research on the potential barriers for Lean and pull system implementation in a company that adopted Lean around two decades ago was made. To collect data for the case study, 17 interviews at different hierarchical levels in the organization were performed. The results of interviews analysis show that Lean and pull requires an integrated implementation of several dimensions.
Assessment of the flexibility of implementing lean tools
Authors: Pessoa B , Ferreira L P , Silva F J G , Sá J C , Ávila P , Ares J E
Published: October 2021

Lean production has already proved to constitute an effective management philosophy when eliminating time loss in production processes. However, achieving economic results is currently insufficient. In the context of this study, research was conducted on the Web of Science platform in order to identify which lean tools are of most widespread use in the process industry, as well as their associated benefits. The publications obtained from this research were subjected to a quantitative analysis, which revealed that 80% of the documents comprise articles from journals, while only 20% appeared in conference proceedings. Of these publications and articles, 44% were cases studies, 35% consisted of research and 21% corresponds to questionnaires. With regard to distribution by country, it was found that approximately 50% of the documents published were limited to only three countries– India, Malaysia and the United States of America. Regarding the sector of activity, this distribution allowed to observe that the metalworking sector is the most targeted, followed by the textile and automotive areas, with a total of 24, 10 and 10 publications, respectively. This analysis allowed one to establish that the most frequently implemented tool mentioned in the articles is VSM (Value Stream Mapping), with a percentage of 65%. This is followed by 5S, which is also of widespread use, representing 48%, when compared to the total number of publications collected in the Web of Science.
Metabolism in eco-holonic manufacturing systems based on the living systems theory
Authors: Ávila M J , Martín A , Aguayo F
Published: October 2021

The industrial metabolism has been conceived on the basis of analogies about the set of biochemical reactions (anabolism and catabolism) that occur in a living being and their flows of matter, energy and substances in natural ecosystems. This conception determines forms of appropriation and consumption of substances, materials and energy, from the natural environment (natursphere) and the technical environment (technosphere) for their transformation and subsequent elimination, under the articulation of criteria of cyclicity, toxicity and efficiency. The last aim of Industrial Ecology (IE), is materialized when the variety of industrial ecosystems is eco-compatible with the variety of natural ecosystems. The naturalisation of manufacturing systems is an effort to conceive them with variety similar to natural systems in order to achieve their eco-compatibility. In addition to bionic models from natural ecosystems in the field of industrial metabolism, several attempts have been made to design technical systems using bionic models from the Living Systems Theory (LST). The formulation of manufacturing systems based on living systems can be considered as a set of dynamic systems from Bertalanffy’s perspective. In this paper is postulated an Eco-Holonic Reference Architecture for its projection in the design of manufacturing systems metabolism with an adaptive, self-regulating and required variety structure and with a potential toolbox in the core knowledge of the holon throughout its life cycle.
Life cycle assessment of accessories of personal protective equipment PPE of easy manufacture: Ear-saver and anti-contact key
Authors: Ayabaca C , Vila C , Zambrano I , Reina S , Cesen M , Carrión M
Published: October 2021

The exponential growth of additive manufacturing techniques and their applications to accessory manufacturing for personal protective equipment (PPE) is becoming a reality. In the forthcoming years it will be able to supply local demands with more efficient and easier to use devices for medical protection. In this article we propose a method of customizing the design and manufacture of PPE accessories such as the Ear-Saver and Anti Contact Key. The proposal considers not only innovative aspects of the product design and rapid manufacturing issues, but also defines a framework considering the product lifecycle and outlines important indicators from economic, social and sustainable perspectives. A set of experimental case studies that are included to enrich the proposed framework and its metrics allows better assessment of the different activities and the environmental impact of the product.
Defectology Characterization of FDM Drilled Parts
Authors: Batista M , Piñero D , Ramírez M , Mayuet P F , Bienvenido R , Vazquez J M
Published: October 2021

Since its emergence, the industry has made great efforts to implement additive manufacturing processes in its production systems. However, to achieve this use, the precision of the parts must also be guaranteed. But it is not yet possible to achieve the characteristics required in certain industrial sectors like the aeronautical where highly rigorous requirements are related to the assembled parts. In this way, alternatives arise, such as the use of machining to obtain the precision required. This concept has been applied for some time to metal parts obtained through additive manufacturing, but not so much to polymer parts. For this reason, given that it is expected that polymeric parts will be used in aeronautical structures, these will have to be machined to obtain the required geometric characteristics. Therefore, in this article, a parametric study of the quality of the holes made in parts obtained by Fused Deposition Modelling (FDM) will be carried out.
Influence of high precision telescopic instrument characterization on multilateration points accuracy
Authors: Aguado S , Brosed F J , Acero R , Aguilar J J , Santolaria J , Pueo M
Published: October 2021

Currently accuracy of manufacturing machines is a must. Verification is the main way to obtain it; highlighting the volumetric verification as the best technique to improve machine tool position accuracy along all its workspace in the shortest time possible. In this way, different measurements based on multilateration techniques like laser tracker and laser tracer are used. This paper studies how characteristics of a new high precision telescopic system consisting in three lines, with measuring principle based on simultaneous laser affect multilateration accuracy to obtain 3D coordinates. The paper analyses instrument characterising both the design, the components and their operation. Moreover, tests carried out study how instruments behavior affect to the accuracy of data capture using analytical and optimization techniques, proving an error estimation depending on the technique used.
Analysis of the effect of porosity on the mechanical behaviour of L-PBF Inconel 718 using XRCT
Authors: Pascual A , Ortega N , Plaza S , Holgado I
Published: October 2021

The scope of this work is to assess the influence of porosity on the mechanical behaviour of L-PBF Inconel 718. To this end, some test specimens were manufactured by L-PBF, according to ASTM E8/E8M. Afterwards, these specimens were scanned by means of XRCT in order to analyse the porosity of each one. The XRCT geometry generated by the previous step were used for FEM analysis. Finally, the results obtained by the analysis were correlated with the experimental results, highlighting the promising future of the proposed methodology.
Tribological characterization of Fused Deposition Modelling parts
Authors: Batista M , Blanco D , Del Sol I , Piñero D , Vazquez J M
Published: October 2021

The customisation or redesign of parts for Additive Manufacturing (AM) to meet the design requirements is an increasing trend. In this context, numerous studies related to the improvement of the mechanical properties of Additive Manufacturing parts used for static applications are emerging. However, the use of these parts in dynamic applications or in relative movement situations has not been deeply developed. Some studies have been focused on the fatigue properties of AM parts while few authors have analysed the sliding behaviour of these parts. This paper presents a characterisation of the wear behaviour of Fused Deposition Modelling (FDM) parts using Pin-on-Disc techniques with the aim of studying their possible implementation in dynamic applications.
Development of a Nakazima formability test methodology for high temperature applications on titanium alloys sheet metal
Authors: Ayllón J , Miguel V , Martínez A , Coello J
Published: October 2021

Forming Limit Curves (FLCs) in applications of hard-to-form materials results essential to optimise the complex forming processes involved. The need of applying high temperature in most of these applications increases the importance of FLCs for cost-effective procedure designs. Nevertheless, either a lack of knowledge is detected relative to this field in literature, or the experimental methods proposed to obtain FLCs result complex to be executed. In the present work, an easy-to-use methodology based on the traditional Nakazima test is proposed and the research has been applied to different titanium alloys. For that, a heated Nakazima device was developed and some new geometry for test samples was proposed. The results agree with those obtained by other authors in similar conditions, what validates the approach developed herein.
Control strategies comparison for a multi-stage assembly system using simulation
Authors: Benavent S , Rosado P , Romero F , Abellán J V
Published: October 2021

The goal of Zero Defect Manufacturing (ZDM) is to reduce part scrap by compensating manufacturing deviations and avoiding their propagation on multi-stage production systems. In particular, the joint use of in-process measuring and flexible locating systems enables the application of different control strategies to proactively improve the geometrical quality of the product and to achieve the productivity targets. In this work, focused on the production quality paradigm, two compensation strategies based on the adjustment of part locators are simulated to compare how different control loops can reduce the out-of-control parts in multi-stage assembly systems. For this purpose, a simulation tool developed on OpenModelica is used taking into account the logistic flow and the quality characteristics flow based on the Stream of Variation model.
Digital twin for the integration of the automatic transport and manufacturing processes
Authors: Martínez* A , Díez J , Verde P , Ferrero R , Álvarez R , Perez H , Vizán A
Published: October 2021

Simulation techniques for time calculation in industrial transport are not currently deterministic. This supposes a time uncertainty in production planning with economic implications. The digitization promoted by Industry 4.0 allows the automation of transport in manufacturing processes. In this way, the Automated Guided Vehicles (AGVs) performance can be simulated to obtain more accurate results. The definition of a virtual simulation environment through digital twins is an incipient area of research in this field. Digital twins achieve this purpose without intervening in the physical world thus minimising costs. In order to facilitate the use of digital twins, in this paper, we implement a web-based simulation service to improve the user experience. The user will be able to pose hypotheses and visualise the execution in real-time. The techniques implemented for the simulations are based on Robot Operating System (ROS) within the Gazebo environment, IIoT communications require the Node-network programming environment which is in charge of the hyperconnectivity and the creation of the user interface.
Productivity tool for automated guided vehicles: OEE indicator perspective
Authors: Ng Corrales L C , Lambán M P , Royo J A , Hernández M E
Published: October 2021

Productivity is a measurement of the efficiency of the resources, constant changes in the environment promote that companies regularly measure their activities. This study aims to define a new metric based conceptually on the traditional OEE. The new indicator measures the efficiency of logistic equipment in this case a system of automated handling: automated guided vehicles (AGVs). The indicator was developed by parameterizing the variables and defining the losses found in the process. It was applied in a factory of car parts and spare parts, two AVGs were analyzed in two different routes. The new indicator was effectively adapted to measure the performance of a logistics equipment. The OEEagv results obtained are those expected by the company, although some authors value the indicator with a higher percentage. Also, the result has shown that a new route could be added for more efficient use of the two AGVs.
Design of a conceptual model for manufacturing companies within the 4th industrial revolution applying the Viable System model
Authors: Gallego S , García M
Published: October 2021

The initiative created under the name “Industry 4.0” in 2011 [3] can help to strengthen the competitiveness of those manufacturing companies [4] able to adapt themselves to this fourth wave of technological advancement driven by various technological advances [5]. Most manufacturing companies have developed departments and initiated projects around the concept Industry 4.0. However, many of them lack the purpose, the organizational acceptance, and the alignment of those activities with the organization´s strategy. Therefore, the aim of this research is to design a conceptual model for improving organizational capabilities thanks to industry 4.0. For this development, the Viable System Model (VSM) was selected as methodological approach. The conceptual model determines the relations between technical areas, technologies, and organizational strategy. The model for Industry 4.0 can help manufacturing companies serving as a guidance for future organizational structure, projects, and activities selection as well as to determine areas with higher potentials according to the status of its technologies and their related current and future capabilities.
Study of additive manufacturing techniques to obtain tactile graphics
Authors: Serrano J , Bruscas G M , Abellán J V , Lázaro R
Published: October 2021

Tactile graphics (TG) are intended to facilitate communication for people with total or partial visual impairment. For this purpose, TG include elements in relief that can be perceived through the sense of touch. TG can be fixed or portable. Fixed TG are expensive, as they are typically produced in very short runs, mostly single part production. Portable TG can be made by thermoforming polymer sheets, but a mould is still required, even though production runs are short (some tens). For this reason, the use of Rapid Manufacturing (RM) and Rapid Tooling (RT) strategies to manufacture TG can be of great interest. In this work, a literature review to study the application of Additive Manufacturing (AM) to obtain TG, both as RM and RT, is carried out. The review reveals the suitability of AM techniques to manufacture TG. In addition, some AM techniques are analysed to be used for a new type of TG, which is based on the deposition of glaze on ceramic tiles.
An overview of the Additive Manufacturing capabilities in the development of rehabilitation products with customized elastic properties
Authors: De La Rosa S , Mayuet P F , Rodríguez L
Published: October 2021

The advantages of AM (Additive Manufacturing) to manufacture complex geometries and custom flexible structures (shape, density, geometry etc.) provides the possibility to use the elastic properties of different materials to design elastic products with “customized” properties in order to obtain damping profiles that could be adapted to a specific energy absorbing application. One of the most widely used materials in the sense of the above is TPU (Thermoplastic Polyurethane). Several compression studies of porous TPU structures proven its effectiveness for shock absorption and have shown that the amount of energy absorbed is influenced by the density of the structure and the type of geometry used, among other parameters. This highlights the possibility of customizing the elastic behaviour of structures and could be implemented in rehabilitation programs which usually use elastic products with highly specific levels of resistance, harder or softer, to try not to strain injured muscles under dynamic loading conditions. However, a high percentage of the current research results is related to the development of support rehabilitation products under static loading conditions such as prostheses and orthotics. This paper aims to overview the current state of additive manufacturing capabilities in the development of rehabilitation products with customized elastic properties.
Occupational health and safety start at school of engineering
Authors: Ramirez M , Pastor A , Diaz E , Piñero D , Batista M
Published: October 2021

The occupational risk prevention has been the subject of study for many years, but it could be said that in Spain, it is from the promulgation of laws in this regard when it becomes more important in view of the need to reduce the accident rate in all professions. Focusing on the engineering profession, the need arises to know if in their training stages, this matter is contemplated by developing a preventive culture in the person that helps to become familiar with and minimize risks. That is why this study aims to find out how this subject is dealt with in Spanish universities. To this end, it proposes the study through the Spanish universities best positioned in international rankings such as the Academic Ranking of World Universities (ARWU) and Quacquarelli Symonds, known as QS World University Ranking. The results of the study show that Spanish universities are not very well disposed towards this subject, thus depriving future engineers of the acquisition of competencies related to risk prevention.
Impact of the current production, supply and consumption standards on the sustainable development goals
Authors: Prado H J , Domingo R
Published: October 2021

Since the industry keeps on evolving, the humankind does not stop squeezing the natural resources and the production standards are set in opposition to the sustainability ideals; the condition of the planet to properly host living beings and the wellbeing of the ecosystems are jeopardized. Lack of concrete data showing the damage caused to the ecosystems prevents leaders, scientists, enterprises and the society overall from making the right decisions to break the vicious circle in which the humanity appears to be captive. Moreover, the role of the industry becomes crucial in order to respond properly and promptly to the climate emergency. This paper compiles the most reliable and current statistics that are key to evaluate and understand the degradation of the planet as well as the initiatives and targets which must be considered in order to tackle the environmental challenges. Furthermore, it aims at changing the industry towards a more sustainable production and use of resources, driven by the Sustainable Development Goals and in particular, by the decarbonization of the industrial activities.
Sustainable and advanced manufacturing processes of light structural materials of the transport sector
Authors: Blanco D , Rubio E M , Marín M M , Camacho A M
Published: October 2021

30% of emissions in the European Union (EU) originate from transport, and there are commitments by all sectors involved, road transport, civil aviation and maritime for a progressive reduction. The mass of the vehicles has a significant influence on their consumption and emissions, so there is a need to replace traditional heavy materials with light structural materials or combinations of them, and to optimise their manufacturing processes. This work reviews the scientific literature published during the period 2015-19. Aiming to select the most relevant articles minimizing the bias, a search strategy is defined, applied in the Web of Science database, and the selection limited to publications in Open Access, English, Q1-Q2 journals or prestigious conference proceedings, from 01/01/2015 to 01/01/2020. The final objective of the work is to provide a global perspective of the latest trends in studies on light structural materials with application in the aeronautical and/or automotive fields, of studies oriented towards sustainability, and with a special interest in those that apply advanced manufacturing and/or machining processes.
Flipped Classroom and gamification in Automated Manufacturing lab classes
Authors: Meana V , Rico J C , Valiño G , Peña F
Published: October 2021

There is an increase in Higher Education initiatives focused on educational innovation and the Flipped Classroom paradigm are emerging as an increasingly expanded option. This paper deals with the implementation of the Flipped Classroom methodology in the laboratory practice sessions of the subject Automated Manufacturing of the Mechanical Engineering Degree. This methodology has been combined with questionnaires through Kahoot, a simple and versatile freeware platform. To carry out this study, additional audio-visual material was developed to illustrate the content of the practices so students could prepare them in advance. Once recorded and edited, the videos were made available through the Virtual Campus. Doing questionnaires at the beginning, and repeated at the end of the sessions, has been an element of reinforcement of learning while stimulating active participation during the classes. It was also a motivating element to work on skills such as proactivity, work organization, teamwork and time management. The students knew beforehand that the result of the questionnaires would influence the grade corresponding to the continuous evaluation. The result of this research concludes that the Flipped Classroom paradigm combined with gamification allows the students to reach good learning outcomes getting them engaged.
Metrics for assessing the economic impacts of power sector climate and clean electricity policies
Authors: Bistline John
Published: October 2021

Modeling tools are increasingly used to inform and evaluate proposed power sector climate and clean electricity policies such as renewable portfolio and clean electricity standards, carbon pricing, emissions caps, and tax incentives. However, claims about economic and environmental impacts often lack transparency and may be based on incomplete metrics that can obscure differences in policy design. This paper examines model-based metrics used to assess the economic efficiency impacts of prospective electric sector policies. The appropriateness of alternative metrics varies by context, model, audience, and application, depending on the prioritization of comprehensiveness, measurability, transparency, and credible precision. This paper provides guidance for the modeling community on calculating and communicating cost metrics and for consumers of model outputs on interpreting these economic indicators. Using an illustrative example of clean electricity standards in the US power sector, model outputs highlight strengths and limitations of different cost metrics. Transformations of power systems with lower-carbon resources and zero-marginal-cost generation may entail shifts in when and where system costs are incurred, and given how these changes may not be appropriately reflected in metrics that were commonly reported in the past such as wholesale energy prices, showing a decomposition of system costs across standard reporting categories could be a more robust reporting practice. Ultimately, providing better metrics is only one element in a portfolio of transparency-related practices, and although it is insufficient by itself, such reporting can help to move dialogues in more productive directions and encourage better modeling practices.
Case report: successful emergent transcatheter pulmonary valve replacement within failing pulmonary artery conduit in the setting of cardiogenic shock with extracorporeal membrane oxygenation support
Authors: Sabbak Nabil , Ghobrial Joanna
Published: October 2021

Background

To the best of our knowledge, this is the first reported case of transcatheter pulmonary valve replacement (TPVR) with extracorporeal membrane oxygenation (ECMO) support with successful decannulation as a bridge to recovery in a young adult with complex congenital heart disease.

Case summary

We describe a 24-year-old male patient with a history of D-transposition of the great arteries with ventricular septal defect status post-Rastelli repair at age three lost to follow-up and presenting with severe biventricular failure, left ventricular thrombus, and critical pulmonary conduit stenosis, deemed non-surgical and non-transplant candidate, who underwent conduit stenting and TPVR in the setting of cardiogenic shock. Upon intubation for general anaesthesia, the patient suffered from ventricular tachycardia arrest requiring cardiopulmonary resuscitation and veno-arterial ECMO. Once stabilized, conduit stenting and TPVR was performed with significant haemodynamic improvement and immediate ECMO decannulation with subsequent biventricular function improvement.

Discussion

In critically ill patients with complex congenital heart disease that are neither surgical nor transplant candidates, ECMO support can be used as a means of support during a transcatheter intervention to improve haemodynamics and a bridge to recovery, allowing time for future potential candidacy for surgery or transplantation as indicated. Patients with congenital heart disease need regular follow-up in specialty clinics to prevent the development of such critical illness.
Auction versus direct sale: the effect of buyers and sellers on prices
Authors: Sogn-Grundvåg Geir , Zhang Dengjun
Published: October 2021

This study examines the question of selling agricultural commodities by auction or directly. Hedonic price analysis using transaction data from the sale of frozen cod in Norway shows that buyer–seller matches explain 32.4 and 13.6 per cent of the price variation in direct sales and auctions, respectively, indicating that direct sales are more informationally efficient than auctions. Meanwhile, auctions gain a price premium of 2.6 per cent over direct sales, holding other variables constant. However, a substantial increase in the use of direct sales indicates that their information efficiency is more important to sellers than the small price premium provided by auctions.
The misuse of distributional assumptions in functional class scoring gene-set and pathway analysis
Authors: Ho Chi-Hsuan , Huang Yu-Jyun , Lai Ying-Ju , Mukherjee Rajarshi , Hsiao Chuhsing Kate
Published: October 2021

Gene-set analysis (GSA) is a standard procedure for exploring potential biological functions of a group of genes. The development of its methodology has been an active research topic in recent decades. Many GSA methods, when newly proposed, rely on simulation studies to evaluate their performance with an implicit assumption that the multivariate expression values are normally distributed. This assumption is commonly adopted in GSAs, particularly those in the group of functional class scoring (FCS) methods. The validity of the normality assumption, however, has been disputed in several studies, yet no systematic analysis has been carried out to assess the effect of this distributional assumption. Our goal in this study is not to propose a new GSA method but to first examine if the multi-dimensional gene expression data in gene sets follow a multivariate normal (MVN) distribution. Six statistical methods in three categories of MVN tests were considered and applied to a total of 24 RNA data sets. These RNA values were collected from cancer patients as well as normal subjects, and the values were derived from microarray experiments, RNA sequencing, and single-cell RNA sequencing. Our first finding suggests that the MVN assumption is not always satisfied. This assumption does not hold true in many applications tested here. In the second part of this research, we evaluated the influence of non-normality on the statistical power of current FCS methods, both parametric and nonparametric ones. Specifically, the scenario of mixture distributions representing more than one population for the RNA values was considered. This second investigation demonstrates that the non-normality distribution of the RNA values causes a loss in the statistical power of these GSA tests, especially when subtypes exist. Among the FCS GSA tools examined here and among the scenarios studied in this research, the N-statistics outperform the others. Based on the results from these two investigations, we conclude that the assumption of MVN should be used with caution when evaluating new GSA tools, since this assumption cannot be guaranteed and violation may lead to spurious results, loss of power, and incorrect comparison between methods. If a newly proposed GSA tool is to be evaluated, we recommend the incorporation of a wide range of multivariate non-normal distributions or sampling from large databases if available.
Identification of a novel Candida metapsilosis isolate reveals multiple hybridization events
Authors: O’Brien Caoimhe E , Zhai Bing , Ola Mihaela , Bergin Sean A , Ó Cinnéide Eoin , O’Connor Ísla , Rolling Thierry , Miranda Edwin , Babady N Esther , Hohl Tobias M , Butler Geraldine
Published: October 2021

Candida metapsilosis is a member of the Candida parapsilosis species complex, a group of opportunistic human pathogens. Of all the members of this complex, C. metapsilosis is the least virulent, and accounts for a small proportion of invasive Candida infections. Previous studies established that all C. metapsilosis isolates are hybrids, originating from a single hybridization event between two lineages, parent A and parent B. Here, we use MinION and Illumina sequencing to characterize a C. metapsilosis isolate that originated from a separate hybridization. One of the parents of the new isolate is very closely related to parent A. However, the other parent (parent C) is not the same as parent B. Unlike C. metapsilosis AB isolates, the C. metapsilosis AC isolate has not undergone introgression at the mating type-like locus. In addition, the A and C haplotypes are not fully collinear. The C. metapsilosis AC isolate has undergone loss of heterozygosity with a preference for haplotype A, indicating that this isolate is in the early stages of genome stabilization.
Determination of Illegally Used Chemical Dyes in the Chinese Herbal Medicine “Red Flower Oil”
Authors: He Yi , Lu Jing , He Fengyan , Zhang Yumei , Wang Feifei , Liu Jingjing , Zheng Xiaowei , Dai Zhong , Ma Shuangcheng
Published: October 2021

Background

Red flower oil is a group of herbal medicinal liniments widely used in China and Southeast Asia. The color of red flower oil is adjusted to red or brownish-red by adding natural dyes.

Objective

The objective of this study is to identify and quantify the synthetic dyes illegally used in red flower oil.

Methods

Thirty-two batches of red flower oil (from nine manufacturers) were collected from different cities in China. High-performance liquid chromatography-diode array detection-mass spectrometry (HPLC–DAD–MS) analysis was performed to identify the chemical dyes in the samples, and high-performance liquid chromatography-diode array detection (HPLC–DAD) was used to quantify the chemical dyes.

Results

Sudan I, Sudan IV, and Solvent Red 207 were detected in nine batches of preparations (from three manufacturers) with concentration ranges of 101.7–214.9 μg/mL for Sudan I, 24.0–41.0 μg/mL for Sudan IV, and 147.5–221.7 μg/mL for Solvent Red 207.

Conclusion

In present study, sudan I, sudan IV, and solvent red 207 were detected in red flower oil. The control of chemical dyes in food and drug should be further studied and not limited to sudan dyes.

Highlights

It is the first report about the detection of solvent red 207 in food and drug. The illegal use of those chemical dyes should be regarded as serious violation of good manufacturing practice (GMP) and might be dangerous for the patients.
Metagenomic Next-Generation Sequencing (mNGS): SARS-CoV-2 as an Example of the Technology’s Potential Pediatric Infectious Disease Applications
Authors: Handel Andrew S , Muller William J , Planet Paul J
Published: October 2021

Metagenomic next-generation sequencing (mNGS) has emerged as a potentially powerful tool in clinical diagnosis, hospital epidemiology, microbial evolutionary biology, and studies of host-pathogen interaction. The SARS-CoV-2 pandemic provides a framework for demonstrating the applications of this technology in each of these areas. In this Supplement, we review applications of mNGS within the discipline of pediatric infectious diseases.
QED in the exact renormalization group
Authors: Igarashi Yuji , Itoh Katsumi
Published: October 2021

The functional flow equation and the quantum master equation are consistently solved in perturbation for chiral symmetric QED with and without four-fermi interactions. Due to the presence of a momentum cutoff, unconventional features related to gauge symmetry are observed even in our perturbative results. In the absence of the four-fermi couplings, a one-loop calculation gives us the standard results of anomalous dimensions and the beta function for the gauge coupling, and therefore the Ward identity, Z1 = Z2. This is a consequence of the regularization-scheme independence in the one-loop computation. We also find a photon mass term. When included, four-fermi couplings contribute to the beta function and the Ward identity is also modified, Z1 ≠ Z2, due to a term proportional to the photon mass multiplied by the four-fermi couplings.
A practical guide to vitiligo differential diagnoses in primary care
Authors: Delgado Patricia , Crumpton Kristen
Published: October 2021

Primary care providers often encounter different types of pigmentary disorders such as vitiligo. This article arms the provider with the most common vitiligo differential diagnoses, with key findings and tips to identify specific hypopigmentary diseases. Readers will be better-prepared to provide safe and effective care and recommend referrals to appropriate specialties.
Moving Away From a “One Size Fits All” Model: Ensuring Opioid Stewardship Includes People Who Use Drugs
Authors: Poteryko Sarah , Nolan Seonaid , Mihic Tamara , Ti Lianping
Published: October 2021

The opioid-driven overdose crisis has had devastating effects across North America, resulting from a complex interplay between individual, social-structural, and environmental factors. Changing approaches to pain management, increased heroin use, and potent synthetic opioids infiltrating the drug supply are compounded by both lack of access to opioid use disorder treatment and surrounding stigma. Inappropriate opioid prescribing practices in healthcare settings have played a central role, and in recent years, there has been increasing interest in implementing hospital-based opioid stewardship programs aimed at improving safety and monitoring opioid prescribing. There is a range of approaches taken by these programs, ranging from audit and feedback to consult services; however, a significant focus of many of these programs is on medication restriction. Such measures stand to negatively impact the care of people with complex healthcare needs, including those currently on long-term opioid therapy, and those with increased opioid tolerance. In this commentary, we emphasize the importance of creating opioid stewardship programs focused on appropriate pain treatment rather than solely on medication restriction to both appropriately prescribe to and manage pain in people who use illicit drugs. This population faces many barriers to care, such as unique dose requirements and high interpatient variability that “one size fits all” stewardship cannot appropriately address. Additionally, opioid stewardship programs that use patient-centered strategies such as multi-disciplinary consult services have been shown to lead to positive health outcomes and have significant potential to address the current shortcomings in pain management for people who use illicit drugs.