bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamic and precise temperature control unit for PEMFC single‐cell testing
Authors: Sabawa Jarek P. , Haimerl Felix , Riedmann Felix , Lochner Tim , Bandarenka Aliaksandr S. 
Published: December 2020

AbstractThe performance and durability of polymer electrolyte membrane (PEM) fuel cells is sensitive to the operating temperature. In order to optimize the operation strategy of PEM fuel cells, it is essential to perform various stress tests within wide temperature ranges. Nevertheless, not all types of stress tests can be performed on the standard single‐cells. For the low‐temperature tests, an additional cooling device is needed, which is associated with high costs and long testing times. In this work, two high power temperature control units were developed. With the small‐size (50 cm2) and automotive‐size (285 cm2) designs, the PEM fuel cell tests at temperatures well below 0°C are possible with the temperature change rates of 80 K min−1. In addition to the high dynamics, the automotive design allows to set the temperature gradients over the active surface area. This offers the possibility to simulate different alteration effects, which can occur during normal operation and increases the comparability between the fuel cell single‐cells and stacks.
Investigation of the impact of EU and governmental measures on the spread and the energy supply of electromobility in Hungary
Authors: Árpád István , T. Kiss Judit , Bellér Gábor , Kocsis Dénes 
Published: December 2020

AbstractThe fight against climate change has brought new technical solutions in the energy industry and transport. Carbon‐neutral solutions, the use of renewable energies have become preferred. Recently, the spread of electromobility in road transport has been increasing worldwide. This situation means new challenges for the energy industry and transport infrastructure. The direction of the development of the society, the energy industry, and the transport is influenced by the governments too. The article studies the governmental and international regulations, guidelines, and plans from the point of view on how these affect the development of transport in Hungary. The authors model the expected spread of electromobility in Hungary. In addition, the authors examine the expected structural transformation of electricity generation, the change expected in the energy mix. Finally, the government's plans are assessed, and it is discussed how Hungary can meet its commitments on renewable energy sources.
Hidden in plain sight: A microanalytical study of a Middle Stone Age ochre piece trapped inside a micromorphological block sample
Authors: Haaland Magnus M. , Strauss André M. , Velliky Elizabeth C. , Mentzer Susan M. , Miller Christopher E. , van Niekerk Karen L. , Henshilwood Christopher S. 
Published: December 2020

AbstractA complete Middle Stone Age ochre piece was unintentionally collected and fully preserved within a micromorphological block sample intended to characterise a 74 ± 3 ka occupation horizon at Blombos Cave, South Africa. Previously recovered ochre pieces from the same stratigraphic context (Still Bay) have displayed intricate modification patterns with significant behavioural implications. Yet, in the case of the trapped ochre, a direct visual assessment of its surfaces was impossible due to its impregnated state. In this study, we demonstrate how we successfully reconstructed three‐dimensionally and characterised the block‐sampled ochre piece using high‐resolution microcomputed tomography scanning coupled with a range of microanalytical techniques, including optical petrography, micro‐Fourier transform infra‐red spectroscopy, micro‐X‐ray fluorescence and micro‐Raman spectroscopy. Through a morphometric analysis of the score marks present on the trapped ochre's reconstructed surface, we were able to assess the types of modifications and the nature of the actions that created them. Our results show that a block sample‐based study of archaeological artefacts allows for a comprehensive assessment of their depositional and microcontextual setting, their external morphology and microtopography, as well as their internal texture and geochemical properties. We suggest that this type of context‐sensitive, multiscalar and multidisciplinary investigation may also prove beneficial in the study of conventionally recovered archaeological artefacts.
Cardiorespiratory fitness, hippocampal subfield volumes, and mnemonic discrimination task performance in aging
Authors: Kern Kathryn L. , Storer Thomas W. , Schon Karin 
Published: December 2020

AbstractAging and exercise have opposing effects on mnemonic discrimination task performance, which putatively taxes pattern separation mechanisms reliant on the dentate gyrus (DG) subfield of the hippocampus. In young adults, increasing cardiorespiratory fitness (CRF) has been shown to improve mnemonic discrimination task performance and increase left anterior DG/CA3 volume. It is unknown how these variables interact in cognitive aging, yet this knowledge is critical, given the established effects of aging on hippocampal plasticity. To investigate these relationships, 65 older adults (aged 55–85 years) completed a submaximal treadmill test to estimate CRF, a mnemonic discrimination task, and a high‐resolution MRI scan to determine hippocampal subfield volumes. Our older adult sample demonstrated the lowest task accuracy in the condition with the greatest stimuli similarity and left DG/CA3 body volume significantly predicted accuracy in this condition. Our results did not provide support for relationships between CRF and task accuracy or CRF and DG/CA3 volume as evidenced in studies of young adults. Instead, CRF predicted bilateral subiculum volume in older adult women, not men. Altogether, these findings provide further support for a role of the DG in behavioral pattern separation in humans and suggest that CRF may have differential effects on hippocampal subfield integrity in older adult men and women.ClinicalTrials.govidentifiers: (a) Neuroimaging Study of Exercise and Memory Function, NCT02057354; (b) The Entorhinal Cortex and Aerobic Exercise in Aging, NCT02775760; (c) Physical Activity and Cognition Study, NCT02773121.
Importance of dose in palliative treatment for incurable head and neck cancer with radiotherapy
Authors: García‐Anaya María J. , Ordoñez Rafael , Toledo María D. , Correa Raquel C. , Otero Ana , Román Alicia , García‐Ríos Isabel , Medina José A. , Gómez‐Millán Jaime 
Published: December 2020

AbstractPurposeTo identify predictors of palliation for head and neck cancer treated with the “Hypo Trial” hypofractionated radiation therapy regimen in a clinical setting.Design/MethodWe retrospectively assessed 106 consecutive patients with incurable cancer, treated between January 2008 and December 2018. Regimen used was 30‐36Gy in 5‐6 biweekly fractions of 6Gy.ResultsThe prescription dose was 30Gy in 57 (53.8%) patients and 36Gy in 49 (46.2%) patients. 89.6% patients completed the prescribed treatment. With a median follow‐up of 6.92 months, 79.2% of the patients experienced clinical palliation. Palliation was correlated with the radiation therapy dose (P = 0.05). Median overall and progression‐free survival (OS, PFS) were 7 and 4.63 months, respectively. Achieving palliation was associated to OS (P = 0.01).ConclusionsThis short palliative hypofractionated scheme resulted in a high rate of palliation, with excellent compliance and acceptable toxicity. Our results show that radiation dose is a predictive factor for palliation.
Practices in software testing in Cameroon challenges and perspectives
Authors: Maxime Carlos Tchinda , Ibrahim Moukouop Nguena 
Published: December 2020

AbstractMany software projects in Cameroon and elsewhere fail to produce the desired quality product due to low adoption of good software testing practices, including test automation. The fundamental questions are what are the local barriers to adopting structured approaches to specifying test cases? And what obstacles are preventing software testing from being automated? To answer these questions, this study analyzes software testing practices in Cameroon. The ultimate objective is to issue recommendations on the directions in which to direct research on software testing, in order to provide solutions promoting the adoption of good testing practices in projects, taking into account limited financial and human resources in developing countries. To do this, a survey was carried out among companies that carry out software development activities. The analysis of the results obtained reveals several interesting elements among which we can cite: (a) more than 80% of the respondents do not ensure that there has been a test other than that of the developer who does not follow a structured approach, (b) automated tests represent less than 8% of the number of tests carried out, (c) the most recurrent factors against test automation are the time required to configure or adapt the tools, the acquisition and implementation costs, costs of design, development, and maintenance of test cases.
Investigation of dengue–malaria coinfection among febrile patients consulting at Ngaoundere Regional Hospital, Cameroon
Authors: Galani Borris R. T. , Mapouokam Danielle W. , Simo Fredy B. N. , Mohamadou Hassimi , Chuisseu Pascal D. D. , Njintang Nicolas Y. , Moundipa Paul F. 
Published: December 2020

AbstractThis study aimed at evaluating the seroprevalence of dengue among malarious patients consulting at the Ngaoundere Regional Hospital. During 2 months and a half, 174 participants were recruited and their blood samples were screened forPlasmodiumspp and then forDenguevirus (DENV) infection using rapid diagnostic tests. Also, hematological asparameters were measured using a hematology autoanalyzer. Among patients tested, 134 (77.01%) were malaria‐positive, and 12/134 (8.95%) were coinfected. In this population, 8/12 (66.67%) were only anti‐DENV IgM‐positive, 3/12 (25%) were both NS1 and anti‐DENV IgM positive, and 1/12 (8.33%) were anti‐DENV IgG‐positive. Furthermore, women were more affected (58.3%) than men (41.7%). The most affected age groups were young people aged less than or equal to 15 years (33.3%) and adults aged between 30 and 45 years (33.3%). A significant association (p < .05; odds ratio [OR] = 5.16) was found between the age range (30–45) and dengue–malaria coinfection. Similarly, we noted a significant association between the coinfection, and joint pain (p < .05; OR = 6.15), fatigue (p < .01; OR = 5.74), and chills (p < .05; OR = 0). Analysis of hematologic parameters showed a significant decrease (p < .001) in platelets in coinfected patients compared with monoinfected patients. In conclusion, dengue–malaria coinfection is a reality in Ngaoundere city and associated with the appearance of clinical features which predict the disease severity.
Autonomous in situ measurements of freshwater alkalinity
Authors: Shangguan Qipei , Lai Chun‐Ze , Beatty Cory M. , Young Fischer L. , Spaulding Reggie S. , DeGrandpre Michael D. 
Published: December 2020

AbstractTotal alkalinity (AT) is an important parameter in the study of aquatic biogeochemical cycles, chemical speciation modeling, and many other important fundamental and anthropogenic (e.g., industrial) processes. We know little about its short‐term variability, however, because studies are based on traditional bottle sampling typically with coarse temporal resolution. In this work, an autonomous AT sensor, named the Submersible Autonomous Moored Instrument for Alkalinity (SAMI‐alk), was tested for freshwater applications. A comprehensive evaluation was conducted in the laboratory using freshwater standards. The results demonstrated excellent precision and accuracy (± 0.1%–0.4%) over the AT range from 800 to 3000 μmol L−1. The system had no drift over an 8 d test and also demonstrated limited sensitivity to variations in temperature and ionic strength. Three SAMI‐alks were deployed for 23 d in the Clark Fork River, Montana, with a suite of other sensors. Compared to discrete samples, in situ accuracy for the three instruments were within 10–20 μmol L−1 (0.3–0.6%), indicating good performance considering the challenges of in situ measurements in a high sediment, high biofouling riverine environment with large and rapid changes in temperature. These data reveal the complex AT dynamics that are typically missed by coarse sampling. We observed AT diel cycles as large as 60–80 μmol L−1, as well as a rapid change caused by a runoff event. Significant errors in inorganic carbon system modeling result if these short‐term variations are not considered. This study demonstrates both the feasibility of the technology and importance of high‐resolution AT measurements.
Direct 3D Printing of Poly(lactic acid) on Cotton Fibers: Characterization of Materials and Study of Adhesion Properties of the Resulting Composites
Authors: Redondo Franco Leonardo , Giaroli María Carolina , Villar Marcelo Armando , de Freitas Augusto Gonzaga Oliveira , Ciolino Andrés Eduardo , Ninago Mario Daniel 
Published: December 2020

AbstractThe aim of this work is focused on the direct 3D‐printing of poly(lactic acid) (PLA) on a cotton textile substrate, and the study of the printing parameters that modify their adhesion. PLA samples are printed by using Fused Deposition Modeling technique (FDM), and three filling printing directions (45, 90 and 180°) are analyzed. The effectiveness of polymer deposition onto fabrics is studied by peeling tests. Adhesion tests revealed that samples printed with a filling direction of 45° presented the maximum adhesion force and separation energies twice higher than samples printed at 180°. These results suggest that printing at 45° filling direction results in higher entanglements between cotton fibers and printed polymer chains, by enhancing the interaction of both materials.
Preparation and Characterization of an Immobilized Enological Pectinase on Agar‐Alginate Beads
Authors: Martín María Carolina , DellÓlio Germán Ariel Gorri , Villar Marcelo Armando , Morata Vilma Inés , López Olivia Valeria , Ninago Mario Daniel 
Published: December 2020

AbstractA commercial enological pectinase is immobilized on agar‐sodium alginate hydrogel beads via external gelation technique. Biocatalyst surface and their internal morphology are characterized by Scanning Electron Microscopy and a good enzyme distribution throughout mixt biopolymer matrix is observed. The biocatalyst is characterized by Fourier Transform Infrared Spectroscopy, confirming the presence of absorption bands associated with amino groups present in the enzyme. Mechanical performance of beads is followed by Texture Profile Analysis and it is demonstrated that agar‐alginate beads exhibited a hardness 3.8 times higher than agar beads. Enzymatic activity of the immobilized pectinase prepared under the optimal conditions reached 0.592 ± 0.041 U per grams of beads. Reusability studies indicated that the immobilized pectinase retained 61% of its initial activity after six successive cycles. The use of the developed biocatalyst decreased significantly the turbidity values after grape must is treated for 120 min at 20 °C. Due to these good properties, the immobilized pectinase synthetized in this work may find applications in the clarification process of winemaking.
Assessment of Biocompatibility and Vascular Effects of Polymeric Materials Using Chick Chorioallantoic Membrane, an Alternative Method
Authors: Dourado Lays Fernanda Nunes , da Silva Carolina Nunes , Arribada Raquel Gregorio , Júnior Armando da Silva Cunha 
Published: December 2020

AbstractDuring the development of polymeric wound coating materials, the in vivo reactions play a key role in the success of the material for tissue engineering. In this work, the chick chorioallantoic membrane (CAM) model is highlighted as an alternative test to evaluate the biocompatibility and changes through the vascular network topography of CAM after the incubation with polymeric membranes. The eggshells of fertilized chicken eggs are opened on the third day of embryo development and the CAM is exposed. Polymeric membranes are placed on the CAM surface and incubated for 96 h. After, the CAM is photographed, the vessels are quantified and histological sections are prepared. In the groups that received spunbonded and cellulose, it is possible to observe tissue growth of the CAM involving the membranes. Regarding the changes in the vascular metrics, a significant increase in the total vessel length and the number of junctions is detected for the spunbonded group. Also, there is an expressive decrease of the lacunarity for this group. Histological analysis revealed an increase of new vessels on the spunbonded, which corroborates to the results mentioned before. The results obtained point out that the CAM assay provides a new perspective on the biocompatibility tests.
Physical, Chemical, Mechanical, and Microstructural Characterization of Banana Pseudostem Fibers from Musa Sapientum
Authors: Silva Fernanda Souza , Ribeiro Carlos Eduardo Gomes , Demartini Tcharllis João da Cunha , Rodríguez Rubén Jesus Sánchez 
Published: December 2020

AbstractThe analysis and exploration of natural fibers in the field of polymer composites contribute to the development of new natural reinforcement materials. This project's purpose is to evaluate the physical (density, diameter, water absorption, and contact angle), chemical (FTIR and TGA), and mechanical properties (tensile strength and pull‐out testing), as well as the microstructural characteristics (confocal laser and electron scanning microscopy) of the pseudostem fiber of the banana type “Bluggoe” (Musa sapientum). The goal is to evaluate its possible applications in the field of polymer compounds based on the observations. The results showed that the fibers presented physical, chemical, and mechanical properties within the expected results for natural fibers. The banana pseudostem fiber presented density of 0.22g/cm³; 49.51% in mass of cellulose, 27.80% of hemicellulose, and 27.77% of lignin; the diameter measurements are 0.293 ± 0.091 mm; and the strength tests have values of 583.46 ± 302.26 MPa. The banana pseudostem‐fiber results are compared to those of other researchers of natural fibers; it is concluded that these banana fibers can be a suitable alternative source to synthetic fibers, and can then be used as reinforcement in laminated composites.
Reclaiming of Vulcanized Rubber Foam Waste from the Shoe Industry Through Solid‐state Shear Extrusion and Compounding with SBR
Authors: Tozzi Kaique Afonso , Canto Leonardo Bresciani , Scuracchio Carlos Henrique 
Published: December 2020

AbstractThe recycling of vulcanized rubber has received intensive attention from the scientific community for many years and yet the disposal of this type of waste remains a subject of major concern. In this study, vulcanized rubber foam waste from the shoe industry is thermo‐mechanically reclaimed through solid‐state shear extrusion (SSSE) with the use of an intermeshing co‐rotating twin‐screw extruder operated at three different temperatures (100 °C, 120 °C and 140 °C). The resulting microstructural, physical and thermal properties are investigated. In addition, compounds based on styrene‐butadiene rubber (SBR) filled with non‐reclaimed and reclaimed rubber foam wastes are compounded in a two‐roll mill and their vulcanization behavior is evaluated by differential scanning calorimetry (DSC) and oscillating disc rheometry (ODR). The crosslinking density and tensile properties of vulcanized hot‐pressed molded compounds are also evaluated. The compounds filled with the reclaimed rubber foam wastes have higher values for the tensile strength and elongation at break compared with the compounds containing the non‐reclaimed waste. The E‐100 modulus remained the same for the different compositions and the best overall performance is achieved for the compound filled with the rubber foam waste reclaimed at 100 °C. This is attributed to the lower crosslink density, which improves the compound homogeneity, as well as the faster revulcanization kinetics of this compound.
Electrostatic or Steric Stabilization of the Cellulose Nanostructures Using Different Modifying Agents
Authors: Camani Paulo Henrique , de Souza Alana Gabrieli , Rosa Derval dos Santos 
Published: December 2020

AbstractCellulose nanostructures (CNSs) are nanoscale biomaterials that have an excellent reinforcing ability; however, due to their high hydrophilic nature, its functionalization is necessary to improve the compatibility between CNS and polymeric matrices. In this work, the CNS‐functionalization with four different modifiers: cationic (CS), anionic (AS), and non‐ionic (NS) surfactant, and GA (grafting agent) is proposed. The modification is conducted in aqueous solution, using three different modifiers contents: 1, 3, and 5 wt%. The modified‐CNS are characterized by Fourier transform infrared spectroscopy (FTIR), X‐ray photoelectron spectroscopy (XPS), zeta potential (ζ), dynamic light scattering (DLS), and thermogravimetric analysis (TGA). CS and AS modifiers acted as electrostatic stabilizers, through charges present in its functional groups (NH3+ and SO3−, respectively); in this case, ζ and XPS results investigated the stabilization. NS and GA modifiers acted as steric stabilizers, due to their polymeric chains, which induces the repulsion between the CNS; the stabilization is confirmed mainly by DLS and XPS. Regarding thermal stability, modified‐CNS samples showed a slight decrease in thermal properties due to the presence of reactive groups in the modifiers. All the samples showed the potential to be applied as fillers in nanocomposites, with degradation temperatures above the biopolymers processing temperatures.
3D Printed Parts of Polylactic Acid Reinforced with Carbon Black and Alumina Nanofillers for Tribological Applications
Authors: Cardoso Paulo Henrique Machado , de Oliveira Marcelo Ferreira Leão , de Oliveira Marcia Gomes , da Silva Moreira Thiré Rossana Mara 
Published: December 2020

Abstract3D printing plays an important role in Industry 4.0 and has versatility to use different materials, including thermoplastic polymers. Polylactic acid (PLA), a bio‐based biodegradable polymer, is used as a potential replacement for petroleum‐based polymers in several applications, and is one of the most popular polymers used in 3D printing. Inorganic/organic nanoparticles can be incorporated in polymers to improve various properties such as thermal, mechanical, and tribological. This work investigates the effect of adding carbon black (CB) and alumina (ALM) nanofillers on the thermal, mechanical, and tribological properties of 3D printed PLA nanocomposites for tribological applications. Both nanofillers promoted progressive enhancement of thermal stability according to TGA. The improvement in the interaction between nanofillers and PLA matrix is revealed by an increase in viscosity of the nanocomposites. The nanocomposites containing 25%wt ALM and 75wt% CB presented better mechanical and wear properties, suggesting synergism between nanofillers and that CB may act as a compatibilizer between PLA and ALM. These results enable selecting the most suitable composition of nanofillers to be added to PLA to create filaments with better tribological properties.