bluuebunny/crossref_metadata_2025 huggingface dataset:
A new methodology using borehole data to measure angular distances between geological interfaces
Authors: Michalak Michał P. , Marzec Paweł , Turoboś Filip , Leonowicz Paulina , Teper Lesław , Gładki Paweł , Pyrcz Michael J. , Szubert Mariusz
Published: May 2023

The study presents a new triangulation-based workflow to assess the degree of parallelism between geological surfaces. This workflow consists of producing and analyzing angular distance distributions as well as conducting spatial analysis using grid maps applicable for subsurface environments with sparse data. We tested our approach using a set of interfaces from Kraków-Silesian Homocline, a geological unit with preferred subhorizontal dip to NE. The pairs of interfaces for angular distance measurements can be divided into two groups: i) separating only Jurassic homocline-related units and ii) separating Jurassic homocline-related units from homocline-unrelated units. To observe potential differences for these two groups, we used bootstrap methods and estimated confidence intervals for summary statistics. In our case, the mean of angular distances turned out to be in general smaller for the pair separating only homocline-related Jurassic sediments. The results also show that the method can be more sensitive to the identification of small-scale structures which are developed only in some of the analyzed surfaces. We provided open-source and freely available computer code to allow reproducibility of the results.
Laser-Directed Energy Deposition of Dissimilar Maraging Steels with a Defect-Free Interface: Design for Improved Surface Hardness and Fracture Toughness
Authors: Deirmina Faraz , Amirabdollahian Sasan , Harris Luke , Bettini Eleonora , Siriki Raveendra , Pellizzari Massimo , Bosetti Paolo , Molinari Alberto
Published: May 2023

Maraging steels are a class of low-carbon ultra-high-strength martensitic steels. Due to their excellent weldability, these steels have been widely applied for laser-based additive manufacturing (AM). MAR-60HRC is a newly developed maraging grade for AM with a nominal chemical composition of 13.0Ni-15.0Co-10.0Mo-0.2Ti, Fe bal. (wt%), capable of achieving hardness levels of ~ 740 HV. Alternatively, 18Ni300 is a commercialized maraging steel with an excellent combination of strength and toughness at the peak aged hardness (i.e., ~ 590 HV). This work aims to investigate the properties and microstructure of MAR-60HRC fabricated by Laser Directed Energy Deposition (L-DED). Further, the manufacturability of bimetallic parts comprising a tough 18Ni300 core and a hard MAR-60HRC on the surface was evaluated. After proper aging, the multi-layered material showed a surface hardness of ~ 720 HV1 and apparent fracture toughness of 71 MPa m1/2, higher than that of MAR-60HRC (i.e., 60 MPa m1/2), and lower than 18Ni300 (i.e., 90 MPa m1/2). The excellent combination of surface hardness and fracture toughness was discussed, considering the crack arrest at the interface and the flawless interface between the two steels.

Graphical Abstract
Linearly combined transition model based on empirical spot growth correlations
Authors: Karsch Maximilian , Van den Eynde Jeroen , Steelant Johan
Published: May 2023

The transition from laminar to turbulent flow in a hypersonic boundary layer is modeled using an intermittency-based linear combination approach. A simplified transition model like this enables a quick assessment of aero-thermal loads and the overall flight efficiency of high-speed vehicles during the initial design phase by weighting purely laminar and turbulent flow results on the basis of an empirically calculated intermittency. The transition model presented within this work includes an empirical model to account for Mach number, Reynolds number, wall temperature and pressure gradient effects on turbulent spot growth based on available turbulent spot studies in the literature. A validation of the transition model is carried out for a number of different test cases and a methodology to extend the model to generic geometries is presented to enable a more general application.
Investigation of Hillslope Failure and Mitigation: A Case Study of Sillewani Ghat, Chhindwara, India
Authors: Dayana Mariya , Sreekantan Parvathi Geetha , Sinha Anil Kumar
Published: May 2023

Hillslope failure along the highway is one of the most hazardous natural phenomena that leads to economic loss. One such slope failure occurred during the 2019 and 2020 monsoon, along National Highway (NH-547) at Sillewani Ghat, Chhindwara, state of Madhya Pradesh, India. After the first failure (2019), the slope was reinstated by the construction of a gabion wall with a mattress. Again, in 2020, the downhill slope failed which resulted in the washing away of one outer lane of pavement while the uphill slope was stable. Detailed field and laboratory investigations were carried out to explore the possible causes of slope failure and recommendations for appropriate remedial measures. Field investigation includes reconnaissance survey, geophysical test (electrical resistivity tomography and seismic refraction tomography), and standard penetration test. Soil and rock samples were collected and different geotechnical characteristics were determined in the laboratory. Seepage coupled slope stability analysis was carried out simulating field conditions. The result of the geotechnical investigation indicates that rock formation is moderately weathered and stable while the downhill slope has four-layers of loose clayey sand, gravel soil, highly and moderately weathered basalt rock. Due to heavy rainfall in 2020, downhill overburden soil (sand and gravel) got saturated and water channel formed at the interface of soil and rock resulted in the slip failure of the slope due to a reduction in effective shear strength. Seepage analysis revealed that phreatic line was existing at shallow depth during heavy rainfall which also supported the failure. Different remedial measures were recommended to reinstate the pavement namely stabilization of slope using soil nailing with and without gabion wall and provision of proper surface/subsurface drainage systems.
Susceptibility and Management of River Bank Materials to Erosion - A Case Study of Ganga-Bhagirathi River, West Bengal, India
Authors: Ghosh Debika , Sahu Abhay Sankar
Published: May 2023

It is very much fundamental to identify the susceptibility of river bank materials to erosion for implementing management strategies. The present paper intends to find out the susceptibility of river bank materials to erosion and it also focuses on vulnerability assessment based on susceptibility of river bank materials to erosion. A vulnerability assessment model based on susceptibility of river bank material to erosion has been used in this study. To satisfy the objectives of this study, a stretch of river Ganga-Bhagirathi in Jangipur sub-division under the district of Murshidabad has been selected. The results of the study show that aggregate stability of the soil in study area is less than 10% and the percentage of aggregated clay (less than 8%) and organic matter (less than 0.5%) in the soil are also very less. The areas categorized as high susceptibility to erosion are highly vulnerable than the rest.
Effective removal of selected pharmaceuticals from sewerage treatment plant effluent using natural clay (Na-montmorillonite)
Authors: Aydin Senar , Celik Karakaya Muazzez , Karakaya Necati , Aydin Mehmet Emin
Published: May 2023

The consumption of pharmaceuticals has rapidly increased on a global scale due to the serious increase in Covid-19, influenza and respiratuar sinsityal virus, which is called “triple epidemic” in the world. The use of non-prescription analgesic and anti-inflammatory drugs (AAIDs), especially paracetamol, is higher compared to pre-pandemic. This increased the AAIDs load discharged to the aqueous media through sewerage treatment plant (STP). Therefore, simple and effective treatment options for removing AAIDs from STP effluents are needed. The aim of the study was to remove AAIDs (paracetamol, acetylsalicylic acid, codeine, diclofenac, ibuprofen, indomethacin, ketoprofen, mefenamic acid, naproxen, and phenylbutazone) from STP effluents by nearly pure natural clay Na-montmorillonite. The Na-montmorillonite taken from the Ordu region in the northern part of Turkey. Surface area of the Na-montmorillonite is 99.58 m2/g and CEC is 92.40 meq/100 g. The removal efficiencies of AAIDs using Na-montmorillonite were between 82 ± 5% (ibuprofen) and 94 ± 4% (naproxen). Paracetamol was used as a model compound in kinetic and isotherm model studies. Freundlich isotherm model and the pseudo second order kinetic model were the best-fit using the obtained experimental data. Film diffusion governed its rate mechanism. The paracetamol adsorption capacity was acquired as 244 mg/g at 120 min contact time at pH 6.5 at 25 °C. With this study, it could be shown that montmorillonite can be used effectively to eliminate paracetamol from STP effluent. Natural clay can be used as a simple, inexpensive and effective adsorbent for removing AAIDs from STP effluents.
The current status of FLASH particle therapy: a systematic review
Authors: Atkinson Jake , Bezak Eva , Le Hien , Kempson Ivan
Published: May 2023

Particle therapies are becoming increasingly available clinically due to their beneficial energy deposition profile, sparing healthy tissues. This may be further promoted with ultra-high dose rates, termed FLASH. This review comprehensively summarises current knowledge based on studies relevant to proton- and carbon-FLASH therapy. As electron-FLASH literature presents important radiobiological findings that form the basis of proton and carbon-based FLASH studies, a summary of key electron-FLASH papers is also included. Preclinical data suggest three key mechanisms by which proton and carbon-FLASH are able to reduce normal tissue toxicities compared to conventional dose rates, with equipotent, or enhanced, tumour kill efficacy. However, a degree of caution is needed in clinically translating these findings as: most studies use transmission and do not conform the Bragg peak to tumour volume; mechanistic understanding is still in its infancy; stringent verification of dosimetry is rarely provided; biological assays are prone to limitations which need greater acknowledgement.
Validation of an FE model updating procedure for damage assessment using a modular laboratory experiment with a reversible damage mechanism
Authors: Wolniak Marlene , Hofmeister Benedikt , Jonscher Clemens , Fankhänel Matthias , Loose Ansgar , Hübler Clemens , Rolfes Raimund
Published: May 2023

In this work, the systematic validation of a deterministic finite element (FE) model updating procedure for damage assessment is presented using a self-developed modular laboratory experiment. A fundamental, systematic validation of damage assessment methods is rarely conducted and in many experimental investigations, only one type of defect is introduced at only one position. Often, the damage inserted is irreversible and inspections are only performed visually. Thus, the damage introduced and, with it, the results of the damage assessment method considered are often not entirely analyzed in terms of quantity and quality. To address this shortcoming, a modular steel cantilever beam is designed with nine reversible damage positions and the option to insert different damage scenarios in a controlled manner. The measurement data are made available in open-access form which enables a systematic experimental validation of damage assessment methods. To demonstrate such a systematic validation using the modular laboratory experiment, a deterministic FE model updating procedure previously introduced by the authors is applied and extended. The FE model updating approach uses different parameterized damage distribution functions to update the stiffness properties of the structure considered. The mathematical formulation allows for an updating procedure that is independent of the FE mesh resolution and free of assumptions about the defect location while only needing few design variables. In this work, the FE model updating procedure is based only on eigenfrequency deviations. The results show a precise localization within $$\pm \, {0.05}{\textrm{m}}$$

±

0.05

m

of the nine different damage positions and a correct relative quantification of the three different damage scenarios considered. With that, first, it is shown that the deterministic FE model updating procedure presented is suitable for precise damage assessment. Second, this work demonstrates that the opportunity to introduce several reversible damage positions and distinctly defined types and severities of damage into the laboratory experiment presented generally enables the systematic experimental validation of damage assessment methods.
Experimental demonstration of 80 kWth chemical looping combustion of biogenic feedstock coupled with direct CO2 utilization by exhaust gas methanation
Authors: Fleiß Benjamin , Bartik Alexander , Priscak Juraj , Benedikt Florian , Fuchs Josef , Müller Stefan , Hofbauer Hermann
Published: May 2023

Chemical looping combustion is a highly efficient CO2 separation technology without direct contact between combustion air and fuel. A metal oxide is used as an oxygen carrier in dual fluidized beds to generate clean CO2. The use of biomass is the focus of current research because of the possibility of negative CO2 emissions and the utilization of biogenic carbon. The most commonly proposed OC are natural ores and residues, but complete combustion has not yet been achieved. In this work, the direct utilization of CLC exhaust gas for methane synthesis as an alternative route was investigated, where the gas components CO, CH4 and H2 are not disadvantageous but benefit the reactions in a methanation step. The whole process chain, the coupling of an 80 kWth pilot plant with gas cleaning and a 10 kW fluidized bed methanation unit were for this purpose established. As OC, ilmenite enhanced with limestone was used, combusting bark pellets in autothermal operation at over 1000 °C reaching high combustion efficiencies of up to 91.7%. The fuel reactor exhaust gas was mixed with hydrogen in the methanation reactor at 360 °C and converted with a methane yield of up to 97.3%. The study showed especially high carbon utilization efficiencies of 97% compared to competitor technologies. Based on the experimental results, a scale-up concept study showed the high potential of the combination of the technologies concerning the total efficiency and the adaptability to grid injection.

Graphical Abstract
Connecting fishing and tourism practices using digital tools: a case study of Marsaxlokk, Malta
Authors: Vegas Macias Jordi , Lamers Machiel , Toonen Hilde
Published: May 2023

Coastal and maritime cultural heritage (CMCH), such as fishing-related activities, seafood and historical buildings along the seafront, is important for connecting and understanding the identity of communities and places linked to the sea. At the same time, CMCH is a key resource for developing tourism in coastal destinations. In tourism development, CMCH is often used and transformed for the benefit of the visitor experience rather than the well-being of the community. Moreover, fishing and tourism practices involved in tourists’ experiences are becoming less integrated in the local community. In this paper, we explore the opportunities that digital tools provide for including fishing communities in the provision of meaningful experiences for tourists. We ask how digital tools can be used to connect fishing and tourism practices. The study is set in Marsaxlokk, a fishing village in the south-east of Malta. An action-research approach is applied to study the use of the storytelling platform izi.TRAVEL as a participatory tool that enables representatives of the fishing community to cocreate and develop heritage tourism experiences based on their CMCH resources. Informed by social practices theory we evaluate how a fishing community can be become more connected to tourism activities and development and discuss the usefulness of the social practices lens to unfold tourism and cultural heritage dynamics. We conclude that digital tools hold both opportunities to raise awareness toward inclusive and sustainable tourism and cultural heritage conservation as well as challenges related to management and digital competences.
Influence of the temperature–time regime on the mechanical properties during the DED-Arc process of near-net-shape Ti-6Al-4 V components
Authors: Gierth Maximilian , Michael Nils , Henckell Philipp , Reimann Jan , Hildebrand Jörg , Bergmann Jean Pierre
Published: May 2023

In a research project, the additive manufacturing process of components made of Ti-6Al-4 V using gas metal arc welding (GMAW), which is classified into the directed energy deposition–arc (DED-Arc) processes, was investigated. The project focused on the systematic development of economical additive build-up strategies and the analysis of the temperature–time regime during the build-up process, as well as the investigation of the resulting properties. A welding range diagram was created with recommendations for process settings for additive manufacturing with the controlled short circuit, as well as a presentation of possible defect patterns outside the range shown. For the fabrication of thick-walled structures, various build-up strategies were investigated by modifying the welding path and evaluated with regard to their suitability. Based on the results, additive structures were fabricated by varying the temperature–time regime in order to gain insights into selected geometrical, metallurgical, and mechanical properties. Different energy inputs per unit length, structure dimensions, and interpass temperatures (IPT) were used for this purpose. The research project provides comprehensive findings on the additive processing of the material Ti-6Al-4 V using metal inert gas welding, in particular with regard to the temperature–time regime and the resulting properties.
Potential Effects of Dynamic Stretching on Injury Incidence of Athletes: A Narrative Review of Risk Factors
Authors: Behm David G. , Alizadeh Shahab , Daneshjoo Abdolhamid , Konrad Andreas
Published: May 2023

The use of dynamic stretching as a replacement for static stretching in the warm-up is widespread based on the reports of static stretching-induced performance impairments. While acute and chronic static stretching has been reported to reduce musculotendinous injuries, especially with explosive and change of direction actions, the influence of dynamic stretching on injury incidence lacks a similar volume of literature for acute and chronic responses. It was the objective of this narrative review to examine the acute and training effects of dynamic stretching on injury incidence and possible moderating variables such as dynamic stretching effects on range of motion, strength, balance, proprioception, muscle morphology, and psycho-physiological responses. One study demonstrated no significant difference regarding injury incidence when comparing a dynamic stretching-only group versus a combined dynamic stretching plus static stretching group. The only other study examined functional dynamic stretching training with injured dancers and reported improved ankle joint stability. However, several studies have shown that dynamic activity with some dynamic stretching exercises within a warm-up consistently demonstrates positive effects on injury incidence. Regarding moderating variables, while there is evidence that an acute bout of dynamic stretching can enhance range of motion, the acute and training effects of dynamic stretching on strength, balance, proprioception, and musculotendinous stiffness/compliance are less clear. The acute effects of dynamic stretching on thixotropic effects and psycho-physiological responses could be beneficial for injury reduction. However, the overall conflicting studies and a lack of substantial literature compared with SS effects points to a need for more extensive studies in this area.
Multi-resonant Controller Design for a PV-Fed Multifunctional Grid-Connected Inverter in Presence of Unbalanced and Nonlinear Load
Authors: Valedsaravi Seyedamin , Aroudi Abdelali El , Barrado-Rodrigo Jose A. , Hamzeh Mohsen , Martínez-Salamero Luis
Published: May 2023

The use of Active Power Filters (APFs) in future power grids with high penetration of nonlinear loads is unavoidable. Voltage Source Inverters (VSIs) interfacing Photovoltaic (PV) generator could play the APF role in addition to power supply. In this paper, the control of a PV-fed multifunctional grid-connected three-phase VSI is addressed with nonlinear and unbalanced load. The control objective is threefold. The first one is to deliver the maximum available power from the PV source to the grid satisfying power quality standards. The second one is the Voltage Balancing Control for DC-link capacitors to guarantee correct operation of the VSI. The last one is shunt APF control to compensate for nonlinear and unbalanced load harmonics, reactive power, and unbalanced sequences. A quasi-Proportional-Resonant (PR) controller with harmonic compensators is proposed for the current control loop. The quasi-PR controller parameters are determined through optimization algorithms such as Particle Swarm Optimization (PSO), Genetic Algorithm (GA), and a combination of both PSO and GA. The aim of the objective function is to improve static and dynamic behavior. The different gains at the fundamental resonant frequency and the selected odd harmonics are obtained for the proposed quasi-PR controller. The dynamic characteristics of the optimized quasi-PR controllers show superiority against conventional ones in terms of gain margin, phase margin, overshoot, and robustness. With the proposed control scheme, the harmonics, reactive power, and unbalanced sequences are appropriately compensated. The performance of the PV-fed VSI shunt APF under irradiance change, load change, and distorted grid voltage conditions is validated through numerical simulations performed on $$\hbox {PSIM}^{\copyright }$$

PSIM
©

software. The results show that the grid currents Total Harmonic Distortion for irradiance change case study are $$4.57\%$$

4.57
%

, $$4.57\%$$

4.57
%

, and $$3.22\%$$

3.22
%

in phase a, b, and c with the proposed control method, while they are $$9.25\%$$

9.25
%

, $$5.65\%$$

5.65
%

, and $$10.12\%$$

10.12
%

with conventional instantaneous $$p-q$$

p
-
q

theory.
The Role of EU Trade Secrets Law in the Data Economy: An Empirical Analysis
Authors: Aplin Tanya , Radauer Alfred , Bader Martin A. , Searle Nicola
Published: May 2023

This article draws on a recently completed study for the European Commission on trade secrets in the data economy. It distils the main findings of that Study and advances it by reflecting on and analyzing these findings in the context of existing legal, management and economics literature, as well as their implications for EU legal policymaking when it comes to trade secrets law. In order to facilitate data sharing, the article argues for a cautious approach, with very modest legislative reforms to the EU Trade Secrets Directive, instead preferring soft law and practical steps to be taken. There is, however, greater scope to reform legal regimes that are complementary to EU trade secrets law, such as thesui generisdatabase right.
Non-contact detection of hidden damages in dispersive media using the instantaneous phase
Authors: Collazos-Burbano David A. , Ealo Joao L. , Orrego-Gonzalez Alejandro
Published: May 2023

The assessment of dispersive media may become a challenge due to the high attenuation ratios, anisotropy and geometrical particularities of the specimen under study. Besides, non-contact methods that preserve the integrity of samples are needed when some degree of purity is required, e.g., when water immersion is not allowed, and the direct contact is not feasible. In this work, we study composite plates, in which acoustic dispersion is present. We use a non-contact hybrid optoacoustic system to implement the experimental setup that makes it possible the detection of the non-exposed damages of the samples. Different relevant aspects, such as cost, maximum frequency achieved, bandwidth, sensitivity, signal-to-noise ratio and spatial resolution were considered before setting the experimental configuration. Though dispersion curves are reconstructed, we emphasize the use of the instantaneous information of signals to detect the faults. Moreover, the instantaneous phase front of the acoustic field becomes a relevant complementary tool for ultrasonic inspection and characterization of dispersive media. In particular, it highlights hidden characteristics which are not visible with other commonly-used representations, namely, the instantaneous amplitude, the time-frequency distributions or the dispersion curves widely employed in non-destructive testing. This work provides an alternative approach to study highly attenuating media where the signal-to-noise ratio is a challenge, and the available scanning path is limited, e.g., layered and poroelastic media such as biological tissues.
Gamified Environments and Serious Games for Students With Autistic Spectrum Disorder: Review of Research
Authors: López-Bouzas Nerea , del Moral-Pérez M. Esther
Published: May 2023

The aim of this study is to review the available research (N = 70) derived from the use of Gamified Environments and Serious Games with people with Autistic Spectrum Disorder (ASD), identifying: authorship, nationality, publication period, topic, and design of the investigation. After that, the advantages and limitations observed are identified. Results indicate that most of them are focused on the design and testing of prototypes, (mostly) linked to the increase of social and emotional skills. The revision highlights that the game’s mechanics and dynamics (feedback, rewards, missions, etc.) involve students from motivation. There is unanimous agreement to emphasize the positive impact of these resources to increment self-control, self-conscience, autonomy, and empathy.
New experimental methodology to evaluate lubrication properties of synovial fluid containing worn tissue particles in osteoarthritis patients
Authors: Dvir Israel , Abd-Rbo Kareem , Segal David , Kandel Leonid Arieh , Kasem Haytam
Published: May 2023

Studying the lubrication properties of osteoarthritis (OA) synovial fluid (SF) enables an understanding of the boundary lubrication joint, mobility, and friction. However, tribology has never been combined with the clinical reality of the presence of worn particles within the synovial fluid and how they affect the osteoarthritic joints. Part of the problem relates to the tribology methods studying friction by applying inadequate pin-on-disc techniques. In this study, synovial fluid with and without worn particles was studied using a customized tribometer. This method enables opening the contact at the end of each cycle and simulates better contact conditions of a natural knee joint and can thus be applied for evaluating the severity of joint OA and the treatment given to the patient.
Novel concept of nano-additive design: PTFE@silica Janus nanoparticles for water lubrication
Authors: Liu Yanfei , He Hailing , Yang Meng , Zhang Ruize , Yu Shengtao , Yang Tiantian , Wang Wenzhong , Liang Fuxin
Published: May 2023

Polytetrafluoroethylene (PTFE) has been widely used as a lubrication additive for reducing friction and wear; however, the hydrophobic nature of PTFE restricts its application in eco-friendly water-based lubrication systems. In this study, for the first time, we designed novel PTFE@silica Janus nanoparticles (JNs) to meet the requirement for additives in water-based lubricants, which have excellent dispersion stability in water attributed to the unique amphiphilic structure. By introducing the lubrication of the aqueous dispersion of the JNs with a concentration of 0.5 wt%, the coefficient of friction (COF) and wear volume were reduced by 63.8% and 94.2%, respectively, comparing to those with the lubrication of pure water. Meanwhile, the JNs suspension also exhibits better lubrication and wear-resistance performances comparing to commercial silica and PTFE suspensions. The excellent tribological behaviors of PTFE@silica JNs as nano-additives could be attributed to the synergetic effect of the two components, where the PTFE provided lubrication through the formed tribofilms on the friction pairs, and the rigid silica further enhanced the wear-resistance performance. Most importantly, the unique structure of JNs makes it possible to use PTFE as an additive in water-lubrication systems. Our study shed light on the design and application of novel JNs nanomaterials as additives to meet the requirements of future industrial applications.
Quantum algorithms: applications, criteria and metrics
Authors: Durán Claudia , Carrasco Raúl , Soto Ismael , Galeas Ignacio , Azócar José , Peña Victoria , Lara-Salazar Sebastián , Gutierrez Sebastián
Published: May 2023

In the field of data processing and IoT communication it is possible to develop more robust solutions by combining quantum algorithms with metaheuristics. Said solutions can be applied in the industry and be measured using metrics associated with complexity, efficiency, processing, and accuracy. An extensive bibliographical review is carried out to determine which is the most efficient and effective hybrid algorithm that can be applied to a real experimental case, which aims to improve communication to reduce occupational risks. Criteria, metrics, and experimental results were obtained, in which it is shown that the quantum genetic algorithm is better than the genetic algorithm. A detailed discussion on the objective function, the convergence to the global optimum, and the need to improve the obtained solutions is given. The conclusions raise new aspects that need investigation.
Liouvillian solutions for second order linear differential equations with Laurent polynomial coefficient
Authors: Acosta-Humánez Primitivo B. , Blázquez-Sanz David , Venegas-Gómez Henock
Published: May 2023

This paper is devoted to a complete parametric study of Liouvillian solutions of the general trace-free second order differential equation with a Laurent polynomial coefficient. This family of equations, for fixed orders at 0 and $$\infty$$
∞
of the Laurent polynomial, is seen as an affine algebraic variety. We prove that the set of Picard-Vessiot integrable differential equations in the family is an enumerable union of algebraic subvarieties. We compute explicitly the algebraic equations of its components. We give some applications to well known subfamilies, such as the doubly confluent and biconfluent Heun equations, and to the theory of algebraically solvable potentials of Shrödinger equations. Also, as an auxiliary tool, we improve a previously known criterium for a second order linear differential equations to admit a polynomial solution.
Governing corporations with ‘strangers’: Earning membership through investor stewardship
Authors: Nordberg Donald
Published: May 2023

Despite decades of theorising and empirical research, the problems of corporate governance seem intractable, particularly the relationships between investors and companies. The thought experiment in this paper asks us to look at the problem through a fresh lens. It draws on the quaint British legal custom of calling shareholders “members”, and then uses the political philosopher Michael Walzer’s idea of membership in states, clubs, neighbourhoods, and families to draw lessons for the corporate world. This paper suggests that seeing how Walzer conceives “strangers” in a polity, with fewer rights but a path to membership, lets us rethink shareholder rights as something to be earned, through engagement and commitment, that is, through stewardship. Rethinking what membership of a company might mean points to a pragmatic escape from short-termism without institutional reform.
Numerical and experimental investigation of a 3D-printed PCU patient-specific cranial implant
Authors: Pisaneschi Gregorio , Mele Mattia , Zucchelli Andrea , Fiorini Maurizio , Campana Giampaolo , Marcelli Emanuela , Tarsitano Achille , Lucchi Elisabetta , Cercenelli Laura
Published: May 2023

Arburg plastic freeforming (APF) technology allows for fabricating patient-specific implants (PSIs) in a hospital environment using medical-grade thermoplastic polymers. Among these materials, poly(carbonate-urethane) (PCU) is of great relevance since it is characterised by excellent biocompatibility. This study explores the opportunity to realise a patient-specific cranial plate via APF. First, a Finite Element model (FEM) of the implant under compressive loads is developed and validated using a quasi-isotropic material. Then, this model is used for Finite Element Analysis (FEA) considering Technical Datasheet (TDS) material properties and those measured on 3D-printed specimens, by Three-Point Bending (TPB) tests. Finally, a PCU PSI is fabricated through APF and tested under static loads to validate the consistency of the numerical results. Considering TDS properties, the FEA results indicate that PCU can be used for the manufacturing of this device. Nonetheless, the TPB tests show that the material suffers from a loss of mechanical properties. Using these properties, the displacements calculated via FEA exceed the admissible values for the application. A further decrease in stiffness is observed in the manufactured plate. Overall, findings suggest that PCU can be a viable material to be printed by APF technology for fabricating craniofacial PSIs, with the advantage of minor stress concentration in critical points of the implant if compared with polyetheretheretherketone (PEEK). However, further studies are necessary to effectively represent the effects of 3D printing in the FEMs used for structural validation and design optimisation.
Fungal Bioremediation of the Plasticizer Hazardous Compound di-2-Ethylhexyl Phthalate (DEHP) in Urine and Blood Bags
Authors: Ali Eman Abdullah M. , Abdel-Rahman Tahany M. A. , Ali Dalia M. I. , Gamal Al-Shaimaa Hossam
Published: May 2023

The hazardous compound di-2-ethylhexyl phthalate (DEHP) is widely used as polyvinyl chloride plasticizer. The present research studied the fungal biodegradation of DEHP contained in blood and urine bags. Soil-plate method was used for fungal isolation from heavily plastic polluted soil using Martin’s and Sabouraud’s agar media, where DEHP was the sole carbon source. Isolated fungal species were identified morphologically according to Moubasher (Soil Fungi in Qatar and Arab Countries University of Qatar, Qatar The Center for Scientific and Research, 1993) as Aspergillus nidulans, Aspergillus niger and Rhizopus nigricans. DEHP concentrations were determined in 1 g of soil, urine bags and blood bags to be 0.92, 2.5 and 2.6 g/l, respectively. Samples of both bags (as a sole carbon source) were artificially inoculated with the isolated fungi and incubated for 20 days. As the time increased, the growth increased where Rhizopus nigricans obtained the highest dry weight in urine bags after 20 days of incubation, while A. nidulans had the highest dry weight in blood bags. Also, a sharp declining of initial pH (6.8) reached 4.7 in urine bags with A. niger growth, while reached 2.5 after A. nidulans growth in blood bags. DEHP% decreased as time increased indicating a continuous DEHP utilization by the three fungal species. Aspergillus niger was the most DEHP degrading fungal species in both bags. Scanning electron microscope examination showed an uniform plastic network in both bags before fungal treatment. While, a microporous network was observed on the plastic surfaces in both bags after fungal treatment due to DEHP utilization. The most DEHP metabolizing fungal species were further identified molecularly using internal transcribed spacer primers to be Aspergillus niger and Aspergillus nidulans with accession numbers MZ832174 and MT919276, respectively.
Semantic Real-Time Mapping with UAVs
Authors: Fanta-Jende Phillipp , Steininger Daniel , Kern Alexander , Widhalm Verena , Apud Baca Javier G. , Hofstätter Markus , Simon Julia , Bruckmüller Felix , Sulzbachner Christoph
Published: May 2023

Whilst mapping with UAVs has become an established tool for geodata acquisition in many domains, certain time-critical applications, such as crisis and disaster response, demand fast geodata processing pipelines rather than photogrammetric post-processing approaches. Based on our 3D-capable real-time mapping pipeline, this contribution presents not only an array of optimisations of the original implementation but also an extension towards understanding the image content with respect to land cover and object detection using machine learning. This paper (1) describes the pipeline in its entirety, (2) compares the performance of the semantic labelling and object detection models quantitatively and (3) showcases real-world experiments with qualitative evaluations.
GRANDPA: GeneRAtive network sampling using degree and property augmentation applied to the analysis of partially confidential healthcare networks
Authors: Bobak Carly A. , Zhao Yifan , Levy Joshua J. , O’Malley A. James
Published: May 2023

Protecting medical privacy can create obstacles in the analysis and distribution of healthcare graphs and statistical inferences accompanying them. We pose a graph simulation model which generates networks using degree and property augmentation and provide a flexible R package that allows users to create graphs that preserve vertex attribute relationships and approximating the retention of topological properties observed in the original graph (e.g., community structure). We illustrate our proposed algorithm using a case study based on Zachary’s karate network and a patient-sharing graph generated from Medicare claims data in 2019. In both cases, we find that community structure is preserved, and normalized root mean square error between cumulative distributions of the degrees across the generated and the original graphs is low (0.0508 and 0.0514 respectively).
Modellierung menschlicher Greifbewegungen für die automatisierte Neurorehabilitation
Authors: Miro Michael , Hoppe Nils , Meisterjahn Peter , Heidrich Sebastian , Kuhlenkötter Bernd
Published: May 2023

Eine der weltweit häufigsten Ursachen für Therapie- und Pflegebedarfe sind neurologisch induzierte Funktionsverluste der oberen oder unteren Extremitäten, wie beispielsweise in Folge eines Schlaganfalls. Die anschließend überwiegend manualtherapeutisch stattfindende Betreuung der Patienten erfolgt allerdings häufig nicht in wünschenswerter Frequenz und Dauer, was die Rekonvaleszenz verzögern kann. Gleichzeitig stellen neurologische Erkrankungen und die resultierenden Funktionsverluste für die Betroffenen einen enormen Eingriff sowohl in das private als auch berufliche Leben dar und kommen aufgrund des demographischen Wandels immer häufiger vor. Um dem Patienten ein automatisiertes Training zur Wiederherstellung der Funktionsverluste zu ermöglichen, ist ein fundiertes Verständnis physiologisch korrekter Bewegungsmuster notwendig. Im Kontext menschlicher Greifbewegungen werden daher existierende Studien sowie der resultierende Forschungsbedarf beschrieben und ein auf die Ableitung von Bewegungskenngrößen ausgerichteter Versuchsaufbau für die oberen Extremitäten entwickelt, bei dem Greifparameter, wie der Objektdurchmesser und die Greifposition, für eine tiefergehende kinematische Betrachtung variiert werden können. Die exemplarisch von einem Therapeuten durchgeführten Greifbewegungen werden mit einem 3D-Kamerasystem ausgewertet, diskutiert und in Form eines Modells zusammengeführt, welches Transport- und Greifphase kombiniert. Das entwickelte Modell erlaubt die Parametrierung der gesamten Greifbewegung insbesondere in Bezug auf Greifort und Objektdurchmesser und wird mit nicht in der Erstellung genutzten Datenpunkten in Bezug auf die Intra-Modell-Plausibilität der generierten Bewegungen hin evaluiert. Zudem wird das Modell mit Bewegungsmustern von zwei weiteren Probanden verglichen, um die Hypothese der grundsätzlichen Eignung der modellierten Bewegungen für die Therapie auf Basis eines qualitativen Vergleichs zu untermauern, ohne Allgemeingültigkeitsanspruch zu erheben. Durch die Nutzung von realen Bewegungsdaten der zwei Phasen wird damit jedoch ein weitaus höherer Authentizitätsgrad des Greifens erreicht, als beispielsweise durch die Nutzung von Standardfahrrampen oder chronologisch unzusammenhängender Bewegungsdaten der Transport- oder Greifphase allein, wie sie in der Literatur vorherrschend sind. Das Modell bietet daher eine Grundlage für ein variantenreiches robotergestütztes Greiftraining im Rahmen der automatisierten Neurorehabilitation.

Praktische Relevanz: Der Einsatz automatisierter Rehabilitationsgeräte unterstützt Therapeuten bei der patientenzentrierten Therapie neurologischer induzierter Funktionsverluste des Bewegungsapparats und ermöglicht den Betroffenen eine schnellere Rekonvaleszenz bei gleichzeitiger Entlastung des therapeutischen Personals. Die physiologisch korrekte Bewegungsanbahnung durch den Roboter stellt in diesem Kontext einen elementaren Therapiebaustein dar.
Changes in formal structure towards self-managing organization and their effects on the intra-organizational communication network
Authors: Maurer Marcel , Bach Norbert , Oertel Simon
Published: May 2023

Changes in organizational structure affect the intra-organizational communication network. However, despite an increasing relevance of less hierarchical and less bureaucratic forms of organizing, the question of how self-managing forms of organization influence employees’ communication behavior has received only scant attention yet. In our study, we analyze the case of a medium-sized firm that experiences organizational change from rigid bureaucratic structures to a more self-managing organization model and question how employees’ centrality in the communication network is affected by this reorganization. Following an explorative research approach informed by prior research on self-managing forms of organizations and communication networks, our findings show that after the change process communication generally is less dependent on formal hierarchy. However, while employees who held a higher rank before the change process loose in centrality, their centrality at the end of the change process is still higher than that of other employees. Moreover, employees who experience a promotion become more central in the communication network while demotions do not have an effect. By discussing these findings in the context of organizational change and the persistence of organizational structures, we contribute to a more comprehensive understanding of the implementation process of self-managing organizations.
(Ex)Change of Routines: An Action-Based Microfoundation
Authors: Kesting Peter
Published: May 2023

Change necessitates companies to alter their established routines. But how flexible are routines, and how can they be changed? Research has given very different answers to this question. While some researchers see routines as rigid and opposed to change, others see them as flexible and a source of change. The problem is not only that these positions are unrelated, but that there is no foundation that conceptually encompasses and connects both elements of routines, rigidity and changeability, which is why these two facets currently present as opposites. Current research tends towards the second position, neglecting the rigidity of routines. This paper offers an action-based microfoundation of routine change expanding Feldman and Pentland’s ostensive-performative approach beyond feedback processes. The focus of the theoretical conceptualization of routines is on action-specific knowledge acquired and applied through repetition. This action-based microfoundation allows the contradictory views of previous research to be positioned in a larger context. Routines are flexible, but only incrementally; they exhibit rigidity towards radical change. Building on this theoretical conceptualization, this paper distinguishes four types of routine changes: routinization/expansion, adaptation, problem fixing, and deliberate routine exchange. This distinction can contribute significantly to the focus of research and thus make it more rigorous. It also allows the rigidities of routines to be taken into account more strongly than before, thereby significantly increasing the relevance of routine research.
Kooperation von Lehrkräften zur Umsetzung von inklusivem Unterricht – notwendige Bedingung, zu einfach gedacht oder überbewerteter Faktor?
Authors: Grosche Michael , Moser Opitz Elisabeth
Published: May 2023

Die interdisziplinäre Kooperation von sonderpädagogischen Lehrkräften und Regellehrkräften wird seit den ersten Schulversuchen zur schulischen Integration bzw. Inklusion in den 1980-iger Jahren als eine zentrale Notwendigkeit von inklusivem Unterricht oder sogar als conditio sine qua non betrachtet. Ob Kooperation aber Inklusion tatsächlich wirksam verbessert, lässt sich bisher kaum beurteilen. Auf der einen Seite fehlen präzise und eindeutige Theorien zu Wirkmechanismen der interdisziplinären Kooperation von Lehrkräften, die erklären könnten, was genau die Wirksamkeitsannahme von Kooperation begründet. Auf der anderen Seite zeigt die Durchsicht empirischer Studien zur Wirksamkeit der Kooperation, dass die Befundlage – anders als in der einschlägigen Inklusionsliteratur dargestellt – ausgesprochen dünn ist. Deshalb plädiert der vorliegende Artikel, Theorien zur Kooperation von Lehrkräften im inklusiven Unterricht zu präzisieren und gezielte empirische Wirksamkeitsstudien zu deren Überprüfung durchzuführen. Hierfür werden Ansatzpunkte skizziert.
Qualität statt Quantität? Zum Zusammenhang von Schreibförderungs- und Feedbackpraktiken mit Textqualität unter Berücksichtigung von migrationsbedingter Mehrsprachigkeit
Authors: Müller N. , Utesch T. , Busse V.
Published: May 2023

Wenngleich ein prozessorientierter Schreibunterricht mit Feedback in Überarbeitungsphasen insbesondere mehrsprachige Lernende beim Schreiben unterstützen kann, ist bislang wenig über entsprechende Unterrichtspraktiken und ihren Einfluss auf Textqualität bekannt. Daher gibt dieser Beitrag Einblicke in gängige Schreib- und Feedbackpraktiken und analysiert unter Einbezug migrationsbedingter Mehrsprachigkeit und weiterer herkunftsbezogener Merkmale, inwieweit diese Praktiken Unterschiede in der Textqualität erklären können. Die Untersuchung unserer Stichprobe von Lernenden an nichtgymnasialen Schulformen in Klasse 9 (N = 208) deutet darauf hin, dass die meisten dieser Lernenden im Deutschunterricht wöchentlich Texte schreiben, allerdings seltener Feedback zum Schreiben erhalten. In Bezug auf die Qualität des Feedbacks konnten keine Unterschiede in der Wahrnehmung zwischen unterschiedlichen Lernendengruppen gezeigt werden, wenngleich Lernende mit Migrationshintergrund sowie speziell Lernende mit anderen Familiensprachen als Deutsch die Fähigkeit ihrer Eltern im Fach Deutsch zu unterstützen als vergleichsweise gering einschätzen. Die Ergebnisse der Regressionsanalysen zeigen, dass wahrgenommene Feedbackqualität (basierend auf Kriterien lernförderlichen Feedbacks) undFeed Forward(also spezielle Hinweise zur Textentwicklung) einen signifikanten Anteil an Varianz der Textqualität vorhersagen, wobei die Ergänzung der Feedbackhäufigkeit das Modell nicht verbessert. Unsere Ergebnisse unterstreichen die Relevanz von Feedback für die Textqualität, wobei diskutiert werden kann, inwieweit die allgemeine Feedbackqualität wichtiger ist als die Feedbackquantität. Zusätzlich zeigen Simple-Slope-Analysen, dass Lernende mit Migrationshintergrund unter Kontrolle weiterer personen- und herkunftsbezogener Merkmale nicht vonFeed Forwardzur Textentwicklung profitieren. Zwar sind gerade Lernende mit Migrationshintergrund auf Feedback angewiesen, um fehlende familiäre Unterstützung auszugleichen − dasFeed Forwardmüsste aber vermutlich besser an die Bedürfnisse dieser Lernenden angepasst werden, um wirksam zu sein.