bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Novel Procedure to Design a Positionable and Stable Drilling Template for Spine Surgery
Authors: Cappetti Nicola , Brancaccio Carmen , De Sio Francesca , Fontana Carlotta 
Published: April 2021

AbstractSpine surgery is based, nowadays, on the use of cutting-edge instruments that optimize the intervention processes in the operating room, with advantages that affect the patient himself. Among these, rapid prototyping is configured as a first-rate tool, thanks to its ability to detail the diagnostic treatment according to the specific pathological case under examination. An example of this technology is represented by the generation of a drilling template, to assist the surgeon in identifying the optimal direction of insertion of the pedicle screws, capable of significantly reduce intervention times, in addition to the inevitable exposure of the patient to ionizing radiation, to which he is subjected during a normal arthrodesis intervention procedure. The design of a drilling guide requires, however, a particular attention in identifying the undercuts present on the vertebral surface, those areas of the spinous process which, reported inside the cavity of the template, involve complications at the time of extraction. In parallel, it is vitally important to carry out an evaluation of its stability during its use. In this article, starting from the analysis of the interferences present during the insertion of the template, a semi-automatic correction model is proposed for the generation of a new profile of the same, which facilitates its extraction without causing injury to the vertebral regions involved from the contact with the mask.
A Framework for Curvature-Based CAD Mesh Partitioning
Authors: Qie Yifan , Qiao Lihong , Anwer Nabil 
Published: April 2021

AbstractIn ISO Geometrical Product Specifications and Verification Standards (GPS) [1], partition is one of the fundamental operations used to obtain ideal or non-ideal features of a product. The operation of partition produces independent geometrical features by decomposing the object. A curvature-based CAD mesh partitioning framework is proposed in this paper. The framework combines several key steps including curvature-based attribute calculation, local shape type refinement, region growing, slippage analysis and statistical modeling. The partitioned features are classified into seven invariance classes of surface in the context of ISO GPS. A case study shows that not only appropriate partitioning but also accurate invariance class recognition for GPS are achieved by the proposed framework.
Modeling Symmetric Minimal Surfaces by Mesh Subdivision
Authors: Rosso Stefano , Curtarello Andrea , Basana Federico , Grigolato Luca , Meneghello Roberto , Concheri Gianmaria , Savio Gianpaolo 
Published: April 2021

AbstractThanks to the great diffusion of additive manufacturing technologies, the interest in lattice structures is growing. Among them, minimal surfaces are characterized by zero mean curvature, allowing enhanced properties such as mechanical response and fluidynamic behavior. Recent works showed a method for geometric modeling triply periodic minimal surfaces (TPMS) based on subdivision surface. In this paper, the deviation between the subdivided TPMS and the implicit defined ones is investigated together with mechanical properties computed by numerical methods. As a result, a model of mechanical properties as a function of the TPMS thickness and relative density is proposed.
A Fast and Reliable Optical 3D Scanning System for Human Arm
Authors: Buonamici Francesco , Carfagni Monica , Puggelli Luca , Servi Michaela , Volpe Yary 
Published: April 2021

AbstractThe article discusses the design of an acquisition system for the 3D surface of human arms. The system is composed by a 3D optical scanner implementing stereoscopic depth sensors and by an acquisition software responsible for the processing of the raw data. The 3D data acquired by the scanner is used as starting point for the manufacturing of custom-made 3D printed casts. Specifically, the article discusses the choices made in the development of an improved version of an existing system presented in [1] and presents the results achieved by the devised system.
Design and Optimization of a Photovoltaic Canopy for an Electric Vehicle Charging Station in Urban Environments
Authors: Parras-Burgos Dolores , Melgarejo-Teruel Jesús , Mateo-Aroca Antonio , Fernández-Pacheco Daniel G. , Cañavate Francisco J. F. , Sáez-Gutiérrez Francisco L. 
Published: April 2021

AbstractNowadays, the use of renewable energies and electric vehicles has become particularly relevant in order to lower the high pollution levels surrounding our cities. The design of a photovoltaic canopy for charging electric vehicles is a highly promising combination that can be set up in urban areas. To favour installing them in different places, this communication provides details of the technico-functional aspects that have been considered to design and fit them, along with other aesthetic and user-centred aspects that help stimulate our society to use such infrastructures.
Develop Model for Controlled Depth Milling by Abrasive Water Jet of Ti6Al4V at Jet Inclination Angle
Authors: Bui Van-Hung , Gilles Patrick , Cohen Guillaume , Rubio Walter 
Published: April 2021

AbstractAbrasive water jet machining (AWJM) is an interesting solution for the production of shallow pockets in metal sheets made of titanium alloys. Indeed, it produces low cutting forces and heat generation and prevents deformation of these parts after machining. In addition, it has the advantage of only using two raw materials: sand and water. It is possible to generate pocket edges with an imposed geometry using AWJM, but it is necessary to tilt the axis of the jet. The material removal mechanism is then a function of the inclination angle. The presented study propose an improved model for modelling the pocket profile in TiAl6V parts. The experimental results shows that the model is efficient as the precision is around 5%.
Digitization of Operational Processes: Use Case of Standardization in an Assembly Learning Factory
Authors: Magnani Florian 
Published: April 2021

AbstractThe objective of this research is to set the ground for new research to measure the impact of Industry 4.0, by combining two types of analysis, that of the performance, and that of the human behaviors, using experiments with digital instruments. A preliminary test, then a first experiment focusing on standardization of operational processes are presented showing promising results to understand how operational and human performance are impacted by the Industry 4.0. This study serves as a first step to a larger research project about productivity measurement of Industry 4.0 transformation.
Essential Issues to Consider for a Manufacturing Data Query System Based on Graph
Authors: Kim Lise , Yahia Esma , Segonds Frédéric , Veron Philippe , Fau Victor 
Published: April 2021

AbstractManufacturing industry data are distributed, heterogeneous and numerous, resulting in different challenges including the fast, exhaustive and relevant querying of data. In order to provide an innovative answer to this challenge, the authors consider an information retrieval system based on a graph database. In this paper, the authors focus on determining the essential functions to consider in this context. The authors define a three-step methodology using root causes analysis and resolution. This methodology is then applied to a data set and queries representative of an industrial use case. As a result, the authors list four major issues to consider and discuss their potential resolutions.
Education in Circular Economy: Focusing on Life Cycle Thinking at the University of the Basque Country
Authors: Minguez Rikardo , Lizundia Erlantz , Iturrondobeitia Maider , Akizu-Gardoki Ortzi , Saez-de-Camara Estibaliz 
Published: April 2021

AbstractSince 2002, the University of the Basque Country (UPV/EHU) has supported several teaching experiences related to the so-called Life Cycle Thinking or Ecodesign in collaboration with local Institutions. The kick off was the Ecodesign Learning Center aiming to promote environmental education at the Faculty of Engineering in Bilbao. In this framework, the last effort has been the implementation of a Master’s Degree entitled Circular Economy: Business Application. This course has been successfully implemented in the 2019–2020 academic year and has been specifically designed to provide training in circular economy for people with backgrounds as varied as product manufacturing engineering, environmental engineering or economics. These studies are aimed to become a European reference in its goal of promoting circular economy, life cycle thinking, ecodesign and sustainable development. This paper analyzes the learning issues and characteristics of this Master's degree placing a special emphasis on its novel competencies and learning outcomes for our society. It can be concluded that the Master's degree is a pioneering teaching experience, being the forefront of Circular Economy Education in Southwestern Europe.
Simulation and Experimental Validation of Secondary Dendrite Arm Spacing for AlSi7Mg0.3 Chassis Parts in Low Pressure Die Casting
Authors: Vergnano Alberto , Bergamini Umberto , Bianchi Daniele , Veronesi Paolo , Spagnolo Roberto , Leali Francesco 
Published: April 2021

AbstractThe structural properties of cast aluminum parts are strongly affected by the solidification in the production process. The solidification dynamics determines the Secondary Dendrite Arm Spacing (SDAS), directly affecting the structural strength of the alloy. Simulation techniques enable the integrated design of chassis parts and their production equipment. However, in order to effectively predict the SDAS formation, the simulation models need to be investigated and calibrated. The present research investigates the SDAS formation models and identifies a robust relation to be used in Design by Simulation phases for AlSi7Mg0.3 parts.
Initial Proposal for a General Systems Engineering Methodology to Early Design Phase Cost/Value Estimation
Authors: Wilson John , Alix Thècle , Gruhier Elise , Maranzana Nicolas , Perry Nicolas , Magnin Gérard , Parrod Nicolas , Servonnat Rémy , Tuery Julien 
Published: April 2021

AbstractWe propose that a systems engineering methodology may be applied in an effective interactive design environment for lifecycle cost estimation and value optimization in the context of a manufacturing enterprise. In order to optimize a product design for value, engineering and manufacturing businesses need to be able to estimate accurately product lifecycle costs during the early design phases of its development, because this is when the majority of these costs are determined. Systems engineering defines realizing value as meeting stakeholder requirements and emphasizes formalizing these in order to link coherently the individual estimated costs of a design to the needs it fulfils. Furthermore, formalized requirement and design parameters are suitable for modelling and simulation, and we envision a systems model implemented within existing knowledge-based engineering tools embedded in a design environment. The results of this model may support design decisions, as well as reinforce systems engineering analyses in evaluating processes for value chain simulations.
Industry 4.0 and BIM: Do They Share the Same Objectives?
Authors: Joblot Laurent , Danjou Christophe , Pellerin Robert , Lamouri Samir 
Published: April 2021

AbstractIn recent years, many changes have been taking place within the construction sector which is much more prone to innovate than in the past. New forms of processes are emerging with the introduction of digital technologies. This article aims to shed light on recent scientific advances that link Industry 4.0 to this sector. To this end, a review of articles published over the past 10 years reporting experiences and gains from 4.0 technologies applied to construction was conducted. It turns out that recent technological developments have brought new functionalities and new perspectives to companies. Some of these were not initially claimed with the sole deployment of a BIM approach. These new opportunities have ultimately raised questions as to whether and how they could impact the speed at which a digital transformation of the sector could take place.
Global symmetry, Euclidean gravity, and the black hole information problem
Authors: Harlow Daniel , Shaghoulian Edgar 
Published: April 2021

Abstract
In this paper we argue for a close connection between the non-existence of global symmetries in quantum gravity and a unitary resolution of the black hole information problem. In particular we show how the essential ingredients of recent calculations of the Page curve of an evaporating black hole can be used to generalize a recent argument against global symmetries beyond the AdS/CFT correspondence to more realistic theories of quantum gravity. We also give several low-dimensional examples of quantum gravity theories which do not have a unitary resolution of the black hole information problem in the usual sense, and which therefore can and do have global symmetries. Motivated by this discussion, we conjecture that in a certain sense Euclidean quantum gravity is equivalent to holography.
$$ T\overline{T} $$-like flows in non-linear electrodynamic theories and S-duality
Authors: Babaei-Aghbolagh H. , Velni Komeil Babaei , Yekta Davood Mahdavian , Mohammadzadeh H. 
Published: April 2021

Abstract
We investigate the $$ T\overline{T} $$
T

T
¯

-like flows for non-linear electrodynamic theories in D(=2n)-dimensional spacetime. Our analysis is restricted to the deformation problem of the classical free action by employing the proposed $$ T\overline{T} $$
T

T
¯

operator from a simple integration technique. We show that this flow equation is compatible with $$ T\overline{T} $$
T

T
¯

deformation of a scalar field theory in D = 2 and of a non-linear Born-Infeld type theory in D = 4 dimensions. However, our computation discloses that this kind of $$ T\overline{T} $$
T

T
¯

flow in higher dimensions is essentially different from deformation that has been derived from the AdS/CFT interpretations. Indeed, the gravity that may be exist as a holographic dual theory of this kind of effective Born-Infeld action is not necessarily an AdS space. As an illustrative investigation in D = 4, we shall also show that our construction for the $$ T\overline{T} $$
T

T
¯

operator preserves the original SL(2, ℝ) symmetry of a non-supersymmetric Born-Infeld theory, as well as $$ \mathcal{N} $$
N
= 2 supersymmetric model. It is shown that the corresponding SL(2, ℝ) invariant action fixes the relationship between the $$ T\overline{T} $$
T

T
¯

operator and quadratic form of the energy-momentum tensor in D = 4.
A worldsheet perspective on heterotic T-duality orbifolds
Authors: Nibbelink Stefan Groot 
Published: April 2021

Abstract
Asymmetric heterotic orbifolds are discussed from the worldsheet perspective. Starting from Buscher’s gauging of a theory of D compact bosons the duality covariant description of Tseytlin is obtained after a non-Lorentz invariant gauge fixing. A left-over of the gauge symmetry can be used to removed the doubled constant zero modes so that D physical target space coordinate remain. This can be thought of as the worldsheet realization of the strong constraint of double field theory. The extension of this description to the heterotic theory is straightforward as all results are written in terms of the invariant and the generalized metrics. An explicit method is outline how to obtain a generalized metric which is invariant under T-duality orbifold actions. It is explicitly shown how shift orbifolds lead to redefinitions of the Narain moduli. Finally, a number of higher dimensional T-folds are constructed including a novel asymmetric ℤ6 orbifold.
Psychiatric hospital reform in low- and middle-income countries: a systematic review of literature
Authors: Raja Tasneem , Tuomainen Helena , Madan Jason , Mistry Dipesh , Jain Sanjeev , Easwaran Kamala , Singh Swaran P. 
Published: April 2021

AbstractPurposePsychiatric hospitals or mental asylums grew across the world in the colonial era. Despite concerns over quality of care and human rights violations, these hospitals continue to provide the majority of mental health care in most low- and middle-income countries (LMICs). We sought to review the evidence of reform of mental hospitals and associated patient outcomes.MethodsWe adopted an integrative review methodology by including experimental and non-experimental research. The review protocol was registered on PROSPERO (CRD42019130399). A range of databases and systematic hand searches were conducted by two independent reviewers. Research conducted between 1980 and May 2019, that focused on any aspect of reform in mental hospitals for adults (age 18 and upwards) with severe mental illness and published in English, were considered.Results16 studies were included in the review. 12 studies met inclusion criteria, and four additional reports emerged from the hand search. Studies covered—India, China, South Africa, Grenada, Georgia, Sri Lanka, Argentina and Brazil. Key findings emphasise the role of judicial intervention as a critical trigger of reform. Structural reform composed of optimisation of resources and renovations of colonial structures to cater to diverse patient needs. Process reforms include changes in medical management, admission processes and a move from closed to open wards. Staff engagement and capacity building have also been used as a modality of reform in mental hospital settings.ConclusionThere is some documentation of reform in psychiatric hospitals. However, poor methodological quality and variation in approach and outcomes measured, make it challenging to extrapolate specific findings on process or outcomes of reform. Despite being integral service providers, psychiatric hospitals still do not adopt patient centric, recovery-oriented processes. Hence, there is an urgent need to generate robust evidence on psychiatric reform and its effect on patient outcomes.
Numerical optimisation of a micro-wave rotor turbine using a quasi-two-dimensional CFD model and a hybrid algorithm
Authors: Tüchler S. , Copeland C. D. 
Published: April 2021

AbstractWave rotors are unsteady flow machines that exchange energy through pressure waves. This has the potential for enhancing efficiency over a wide spectrum of applications, ranging from gas turbine topping cycles to pressure-gain combustors. This paper introduces an aerodynamic shape optimisation of a power generating non-axial micro-wave rotor turbine and seeks to enhance the shaft power output while preserving the wave rotor’s capacity to function as a pressure-exchanging device. The optimisation considers six parameters including rotor shape profile, wall thickness, and number of channels and is done using a hybrid genetic algorithm that couples an evolutionary algorithm with a surrogate model. The underlying numerical model is based on a transient, reduced-order, quasi-two dimensional computational fluid dynamics model at a fixed operating condition. The numerical results from the quasi-two-dimensional optimisation indicate that the best candidate design increases shaft power by a factor of 1.78 and imply a trade-off relationship between torque generation and pressure exchange capabilities. Further evaluation of the optimised design using three-dimensional computational fluid dynamics simulations confirms the increase in power output at the cost of increased entropy production. It is further disclosed that increased incidence losses during the initial opening of the channel to the high-pressure inlet duct compromise the shock strength of the primary shock wave and account for the decrease in pressure ratio. Finally, the numerical trends are validated using experimental data.
Identification and quantification of dicarboxylic fatty acids in head tissue of farmed Nile tilapia (Oreochromis niloticus)
Authors: Lehnert Katja , Rashid Mamun M. , Barman Benoy Kumar , Vetter Walter 
Published: April 2021

AbstractNile tilapia (Oreochromis niloticus) was grown in Bangladesh with four different feeding treatments as part of a project that aims to produce fish in a cost-effective way for low-income consumers in developing countries. Fillet and head tissue was analysed because both tissues were destined for human consumption. Gas chromatography with mass spectrometry (GC/MS) analyses of transesterified fatty acid methyl ester extracts indicated the presence of ~ 50 fatty acids. Major fatty acids in fillet and head tissue were palmitic acid and oleic acid. Both linoleic acid and polyunsaturated fatty acids with three or more double bonds were presented in quantities > 10% of total fatty acids in fillet, but lower in head tissue. Erucic acid levels were below the newly proposed tolerable daily intake in the European Union, based on the consumption of 200 g fillet per day. Moreover, further analysis produced evidence for the presence of the dicarboxylic fatty acid azelaic acid (nonanedioic acid, Di9:0) in head tissue. To verify this uncommon finding, countercurrent chromatography was used to isolate Di9:0 and other dicarboxylic acids from a technical standard followed by its quantification. Di9:0 contributed to 0.4–1.3% of the fatty acid profile in head tissue, but was not detected in fillet. Fish fed with increasing quantities of flaxseed indicated that linoleic acid was the likely precursor of Di9:0 in the head tissue samples.