bluuebunny/crossref_metadata_2025 huggingface dataset:
Kinematics, deformation partitioning and late Variscan magmatism in the Agly massif, Eastern Pyrenees, France
Authors: Vanardois Jonas , Trap Pierre , Goncalves Philippe , Marquer Didier , Gremmel Josselin , Siron Guillaume , Baudin Thierry
Published: July 2020

In order to constrain the finite deformation pattern of the Variscan basement of the Agly massif, a detailed structural analysis over the whole Agly massif was performed. Our investigation combined geological mapping, reappraisal of published and unpublished data completed with our own structural work. Results are provided in the form of new tectonic maps and series of regional cross-sections through the Agly massif. At variance from previous studies, we identified three deformation fabrics named D1, D2 and D3. The D1 deformation is only relictual and characterized by a broadly northwest-southeast striking and eastward dipping foliation without any clear mineral and stretching lineation direction. D1 might be attributed to thickening of the Variscan crust in a possible orogenic plateau edge position. The D2 deformation is a heterogeneous non-coaxial deformation, affecting the whole massif, that produced a shallowly dipping S2 foliation, and an anastomosed network of C2 shear zones that accommodated vertical thinning and N20 directed extension. D2 is coeval with LP-HT metamorphism and plutonism at ca. 315–295 Ma. D2 corresponds to the extensional collapse of the partially molten orogenic crust in a global dextral strike-slip at the scale of the whole Variscan belt. The D2 fabrics are folded and steepened along a D3 east-west trending corridor, called Tournefort Deformation Zone (TDZ), where the Saint-Arnac and Tournefort intrusives and surrounding rocks share the same NE-SW to E-W subvertical S3 foliation. Along the D3 corridor, the asymmetrical schistosity pattern and kinematic criteria suggest a D3 dextral kinematics. The D3 deformation is a record of E-W striking dextral shearing that facilitated and localized the ascent and emplacement of the diorite and granitic sheet-shaped plutons. D3 outlasted D2 and turned compressional-dominated in response to the closure of the Ibero-Armorican arc in a transpressional regime. The progressive switch from D2 thinning to D3 transpression is attributed to the lessening of gravitational forces at an advanced stage of extensional collapse that became overcome by ongoing compressional tectonic forces at the southern edge of the Variscan orogenic plateau.
La thérapie génique des rétinites pigmentaires héréditaires
Authors: Ducloyer Jean-Baptiste , Le Meur Guylène , Cronin Thérèse , Adjali Oumeya , Weber Michel
Published: July 2020

Les rétinites pigmentaires, ou dystrophies rétiniennes héréditaires, sont des maladies dégénératives cécitantes d’origine génétique. La thérapie génique est une approche révolutionnaire en plein essor qui ouvre la voie au traitement de maladies jusqu’ici incurables. Une thérapie génique, le Luxturna®, a obtenu une autorisation de mise sur le marché par la FDA (Food and Drug Administration) fin 2017 et l’EMA (European Medicines Agency) fin 2018. Ce traitement, à l’efficacité démontrée, destiné aux patients porteurs d’une amaurose congénitale de Leber ou d’une rétinopathie pigmentaire en lien avec une mutation bi-allélique du gène RPE65, apporte beaucoup plus de questions que de réponses. Nous présentons, dans cette revue, les avancées actuelles, puis les défis technologiques, économiques et éthiques à surmonter pour que la thérapie génique améliore nos pratiques médicales.
Nouvelle approche thérapeutique pour les rétinites pigmentaires
Authors: Goureau Olivier , Orieux Gaël
Published: July 2020

Dans les maladies dégénératives de la rétine affectant les photorécepteurs, la transplantation de cellules permettant la restauration de la vision est aujourd’hui envisagée. La dernière décennie a vu des progrès remarquables dans la génération de cellules de rétine à partir de cellules souches pluripotentes humaines avec, en particulier, le développement de systèmes de culture en trois dimensions (3D) permettant la génération d’organoïdes de rétine. Dans cette revue, nous faisons un état des lieux sur les stratégies précliniques menées dans des modèles animaux pour le remplacement des photorécepteurs par des photorécepteurs dérivés de cellules souches et présentons les obstacles importants qui restent à être surmontés.
Mieux comprendre l’incertitude en médecine pour former les médecins
Authors: Motte Baptiste , Aiguier Grégory , Van Pee Dominique , Cobbaut Jean Philippe
Published: July 2020

Contexte :  Mal gérée ou mal tolérée, l’incertitude en médecine a des conséquences néfastes pour le patient et/ou le praticien. Dans la littérature, il n’existe pas de modèle explicatif global des différentes dimensions de l’incertitude à laquelle nous sommes confrontés dans le soin, sur lequel fonder une démarche pédagogique. But : L’objet de notre travail est d’élaborer un modèle pour penser l’incertitude en tant qu’objet d’apprentissage en médecine générale. Méthode : Nous effectuons une revue de la littérature des différentes définitions de l’incertitude dans la base de données PubMed, en présentons une synthèse chronologique et sélectionnons une taxonomie qui catégorise les multiples variétés de l’incertitude médicale. Nous confrontons ensuite cette taxonomie aux résultats d’une étude sociologique réalisée par Bloy qui décrit les différentes attitudes des médecins généralistes face à l’incertitude. À l’aide de cartes conceptuelles itératives, nous construisons un modèle explicatif de la gestion de l’incertitude médicale et en explorons les concepts clés. Résultats : Il ressort de notre analyse que la nature même de la médecine en tant que pratique soignante génère des incertitudes complexes. Gérer ces incertitudes requiert une meilleure compréhension du rapport des soignants aux savoirs et à leurs mises en œuvre dans la pratique. Former à la gestion de l’incertitude devrait favoriser l’exploration et l’enrichissement des épistémologies personnelles et pratiques. Conclusion : Nous discutons l’impact des concepts clés de notre modèle sur la pédagogie médicale et argumentons la pertinence de l’approche pragmatiste dans cette perspective. Nous proposons des pistes pour sa mise en œuvre.
Hepatolienale Candidose als seltene Differenzialdiagnose disseminierter kleinherdiger Parenchymveränderungen
Authors: Kloth Christopher , Breining T. , Wowra T. , Hönig M. , Beck A. , Beer M. , Schmidt S. A.
Published: July 2020

Anamnese und klinischer Befund Wir berichten über einen 17-jährigen Patienten mit dem Sekundärmalignom einer akuten myeloischen Leukämie (AML). Dieser entwickelte während der hämatopoetischen Stammzelltransplantation ein persistierendes Fieber unklarer Genese.

Untersuchungen In der stufenweise erfolgten Fokussuche zeigten sich in der routinemäßig durchgeführten Sonografie des Abdomens disseminierte echoarme, kleinherdige Parenchymläsionen der Leber. In der ergänzenden MRT zeigten sich nach Kontrastmittelgabe disseminierte kleinherdige Aussparungen des Leberparenchyms und der Milz.

Diagnose Bildgebend ergab sich der Verdacht einer hepatolienalen Candidiasis.

Therapie und Verlauf Unter einer empirischen Therapie mit Amphotericin B erfolgte die gezielte sonografische Stanzbiopsie der Leber. Hierbei ergaben sich in der pathologischen Aufarbeitung rundlich-ovale Partikel in der PAS-Färbung im Sinne einer opportunistischen Mykose vom Typ einer Candida-Infektion.

Folgerung Der Fall zeigt, dass bei immunsupprimierten Patienten stets die Candidose als Differenzialdiagnose bei gleichzeitigen Parenchymveränderungen von Leber und/oder Milz zu berücksichtigen ist. Ferner sollte in der Screening-Situation bei der Fragestellung nach Pilzläsionen in Leber und Milz zwingend zusätzlich ein geeigneter Linearschallkopf angewandt werden. Alternativ ist bei der Verdachtsdiagnose zügig eine kontrastangehobene MRT des Abdomens als bildgebende Modalität durchzuführen.
Akzeptanz von Versorgungsangeboten zur ausschließlichen
Fernbehandlung am Beispiel des telemedizinischen Modellprojekts
„docdirekt“: ein Mixed-Methods Design
Authors: von Solodkoff Michail , Strumann Christoph , Steinhäuser Jost
Published: July 2020

Ziel der Studie Aktuelle telemedizinische Angebote, wie das in
Baden-Württemberg (BW) laufende Modellprojekt
„docdirekt“, beinhalten eine Begleitevaluation, die die
Implementierung der Anwendung optimieren soll. Anhand der Ergebnisse dieser
Evaluation lassen sich Strategien zur Anpassung des Angebots der
ausschließlichen Fernbehandlung identifizieren, um dieses langfristig in
die Regelversorgung zu integrieren.

Methodik Im ersten Teil der Studie wurden Probanden aus BW in
Einzelinterviews zu Erwartungen, fördernden Faktoren und Barrieren bei
der Nutzung von Versorgungsangeboten zur ausschließlichen Fernbehandlung
befragt. Die mit der qualitativen Inhaltsanalyse nach Mayring explorierten
Determinanten wurden dann im zweiten Teil mittels einer quantitativen Befragung
von zufällig ausgewählten Bürgern aus BW
priorisiert.

Ergebnisse 27 Probanden (MW: 51 Jahre, min: 23 Jahre, max: 86 Jahre)
nahmen an den Interviews teil. Sie empfanden v. a. die schnelle
Erreichbarkeit von medizinischem Fachpersonal als großen Vorteil. Als
förderlich wurde u. a. eine „24/7“ Hotline
benannt sowie die Möglichkeit elektronische Rezepte oder
Arbeitsunfähigkeitsbescheinigungen ausgestellt zu bekommen. Als
Barrieren wurden u. a. der Datenschutz und eine fehlende
körperliche Untersuchung wahrgenommen. Bei der Fragebogenerhebung wurde
von den Teilnehmern (n=217, Rücklauf 10,9%, MW: 53
Jahre, min: 19 Jahre, max: 88 Jahre) der „schnelle ärztliche
Kontakt“ bei einer Behandlung per Videotelefonie, gefolgt von der
„Möglichkeit einen Spezialisten (Facharzt) vermittelt“
zu bekommen und „einen ersten Therapievorschlag“ zu erhalten als
am wichtigsten bewertet. Insgesamt schlossen n=71 (34,6%) die
Nutzung eines solchen Angebots für sich aus. Die Nutzungsbereitschaft
sinkt mit zunehmendem Alter und abnehmender digitaler Affinität.

Schlussfolgerung Die Studie zeigt, dass Interesse an der Nutzung von
Versorgungsangeboten zur ausschließlichen Fernbehandlung besteht.
Personen mit Nutzungsabsicht priorisieren dabei die schnelle medizinische
Ersteinschätzung sowie die Komfort-Aspekte und betrachten u. a. die
Einbindung weiterer Dienstleistungen als förderlich. Es gilt im
nächsten Schritt die erhobenen Determinanten in das Angebot
einfließen zu lassen.
Differentiation Between Anteroposterior and Posteroanterior Chest X-Ray View Position With Convolutional Neural Networks
Authors: Hosch René , Kroll Lennard , Nensa Felix , Koitka Sven
Published: July 2020

Purpose Detection and validation of the chest X-ray view position with use of convolutional neural networks to improve meta-information for data cleaning within a hospital data infrastructure.

Material and Methods Within this paper we developed a convolutional neural network which automatically detects the anteroposterior and posteroanterior view position of a chest radiograph. We trained two different network architectures (VGG variant and ResNet-34) with data published by the RSNA (26 684 radiographs, class distribution 46 % AP, 54 % PA) and validated these on a self-compiled dataset with data from the University Hospital Essen (4507, radiographs, class distribution 55 % PA, 45 % AP) labeled by a human reader. For visualization and better understanding of the network predictions, a Grad-CAM was generated for each network decision. The network results were evaluated based on the accuracy, the area under the curve (AUC), and the F1-score against the human reader labels. Also a final performance comparison between model predictions and DICOM labels was performed.

Results The ensemble models reached accuracy and F1-scores greater than 95 %. The AUC reaches more than 0.99 for the ensemble models. The Grad-CAMs provide insight as to which anatomical structures contributed to a decision by the networks which are comparable with the ones a radiologist would use. Furthermore, the trained models were able to generalize over mislabeled examples, which was found by comparing the human reader labels to the predicted labels as well as the DICOM labels.

Conclusion The results show that certain incorrectly entered meta-information of radiological images can be effectively corrected by deep learning in order to increase data quality in clinical application as well as in research.

Key Points: 

Citation Format
Women in Leadership
Authors: Wells Katerina , Fleshman James W.
Published: July 2020

The role of a surgeon is inherently that of a leader and as women become a larger minority in surgical specialties, the next step becomes greater representation of women in positions of surgical leadership. Leadership is a relationship of granting and claiming wherein society must accept that women are deserving of leadership and women must realize their rightfulness to lead. Implicit gender bias undermines this relationship by perpetuating traditional gender norms of women as followers and not as leaders. Though female representation in academia and leadership has increased over the past few decades, this process is unacceptably slow, in part due to manifestations of implicit bias including discrimination within academia, pay inequality, and lack of societal support for childbearing and childcare. The women who have achieved leadership roles are testament to woman's rightfulness to lead and their presence serves to encourage other young professional women that success is possible despite these challenges.
Mass–elite differences in new democracies: Tunisia as a case study (2010–2016)
Authors: Farag Mahmoud
Published: July 2020

This article argues for inductive exploration of mass–elite differences in new democracies. Grounded in the “delegate model” of political representation, I do this by studying issue positions and issue salience of masses before turning to elites. The article demonstrates this approach using Tunisia, the only Arab democracy, by analysing survey data and originally coded party manifesto data. From an issue position perspective, the article uncovers mass–elite incongruence on the democratic–authoritarian and secular–Islamist political dimensions. From an issue salience lens, there is mass–elite congruence on the economic dimension. How mass–elite incongruence unfolds might affect the future of democracy in Tunisia.
Estimating the spatiotemporal potential of self-consuming photovoltaic energy to charge electric vehicles in rural and urban Nordic areas
Authors: Shepero Mahmoud , Lingfors David , Widén Joakim , Bright Jamie M. , Munkhammar Joakim
Published: July 2020

The penetration of electric vehicles (EVs) and photovoltaic (PV) systems has increased globally in the last decade. For planning purposes, the spatiotemporal variability of distributed PV power generation and EV charging needs to be quantified for urban and rural areas. This study introduces a state-of-the-art, open, and generally applicable model framework for assessing the spatiotemporal mismatch between EV load and PV generation for urban and rural areas. The model is applied to a rural and an urban area, both 16 km × 16 km and located in Sweden, and is evaluated for the extreme months of January and July. The results show that an energy deficit of, at most, 86% and an up to ten times surplus took place in January and July, respectively. A high self-consumption (SC) of 77% was observed for January and a high self-sufficiency (SS) of 69% for July. This is to say that during July, PV can fulfill 69% of the EV charging load. Moreover, there were no observed correlations between the PV-EV temporal matching scores (the SS and the SC) and the dominant type of charging, e.g., workplace charging in each grid cell (1 km × 1 km) of the areas. This can be partially attributed to the wide distribution of the rooftop orientations in both areas. This challenges the assumption of low PV-EV temporal matching in residential parts of the city. Applying the proposed methodology to other regions is incentivized.
Micromagnetic simulation of the temperature dependence of the switching energy barrier using string method assuming sidewall damages in perpendicular magnetized magnetic tunnel junctions
Authors: Naganuma Hiroshi , Sato Hideo , Ikeda Shoji , Endoh Tetsuo
Published: July 2020

The influence of magnetic damages at the sidewall of perpendicular magnetic tunnel junctions (p-MTJs), which are the core devices of spin-transfer-torque magnetoresistive random-access memory (STT-MRAM), is discussed based on the thermal stability factor, Δ, double-logarithmic plot of normalized switching energy barrier, E, and saturation magnetization, Ms, and their exponential slope, n. Δ was calculated using the string method under the simulation conditions of domain wall motion switching. n increased with the increasing thickness of the damaged layer of the sidewall. Notably, the sidewall damage can be explained by the reduction in Ms and exchange stiffness constant, As, rather than the interfacial perpendicular anisotropy. The findings of this study are important for controlling and improving the process damage in the mass production of p-MTJs in STT-MRAM.
The role of hafnium acetylacetonate buffer layer on the performance of lead halide perovskite solar cells derived from dehydrated lead acetate as Pb source
Authors: Sanni D. M. , Ntsoenzok E. , Saintaimé E. , Adeniji S. A. , Oyelade O. V. , Koech R. K. , Amune D. I. , Bello A.
Published: July 2020

In this research, we demonstrated the use of hafnium acetylacetonate (Hfaca) dissolved in ethanol as a buffer layer for perovskite solar cells from non-halide Pb (dehydrated lead acetate) source material. The inverted p-i-n planar heterojunction structure was employed in this work. A one step spin-coating method was used in depositing the perovskite solution before thermal annealing at 90 °C for 5 min to form the perovskite film. Hfaca has been previously used as a buffer layer, but the optimal concentration has not been reported. The optimum concentration of Hfaca was found to be 1.0 mg/ml, resulting in a power conversion efficiency (PCE) of 12.23% corresponding to more than 30% improvement when compared to the control device (phenyl-C61-butyric acid methyl ester/Ag) without Hfaca, which has a PCE of 8.89%. Hfaca as a buffer layer leads to superior stability, retaining about 90% of its original PCE values after 15 days of storage in a glove box, compared to the control device, which retains 70% of the initial PCE value under the same storage.
New Bidentate N-Sulfonyl-Substituted Aromatic Amines as Chelate Ligand Backbones: Pd Catalyst Generation in C–C Coupling via In Situ and Precatalyst Modes
Authors: Oloyede Hammed Olawale , Akong Akong Raymond , Woods Joseph Anthony Orighomisan , Görls Helmar , Plass Winfried , Eseola Abiodun Omokehinde
Published: July 2020

A series of six new, bidentate ligands based on N-(2-(R-sulfonamido)benzyl)R-sulfonamide have been isolated as dianionic or monoanionic chelators via condensation of 2-(aminomethyl)aniline with sulfonyl chloride reagents; R=methyl (1 and 1′), tolyl (2 and 2′), 2,4,6-trimethylphenyl (3), or 2,4,6-triisopropylphenyl (4). Complexes of ligands 2–4 reacted at room temperature with palladium(ii) acetate in the presence of various monodentate N-donor co-ligands to form complexes Pd2(2dmap), Pd2′(OAc.py), Pd3(2acn), Pd3(2py), Pd4(2acn), and Pd4(2py), which were structurally confirmed by three X-ray crystal analyses. Results of catalysis studies in water showed high turnover frequencies and yields of up to 98% within 10min and at 0.2 mol-% palladium catalyst loading. Relative to ligand-free catalysis in the presence of only Pd(OAc)2, the ligand-supported palladium species clearly possess positive catalytic advantage. Furthermore, Suzuki coupling efficiencies by 1:1 ‘Pd(OAc)2+ligand’ yielded notably better outcomes than for the 1:2 ‘Pd(OAc)2+ligand’ insitu catalyst generation, which reveals that coordinative saturation is undesirable. The size of the complementing monodentate co-ligand was observed to influence the catalytic efficiency such that bulkier co-ligands consistently yielded improved turnover frequency values, which leads to the conclusion that steric repulsion between the synthesised ligands and the bulkier co-ligands aided the generation of vacant coordination sites for the more active complexes. Moderate Heck coupling activity was recorded for the complexes and better activities appear to correlate with moderate bulkiness of ligand 3.
Calibration of underwater fisheye camera with multi-frequency heterodyne technique based on light field
Authors: Xie LiangLiang , Zhang Xu , Tu Dawei , Li Chen , Xiao Guoliang , Zhang Can , Zhuang Sufeng
Published: July 2020

In this paper, a novel approach is proposed to calibrate an underwater fisheye camera with the multi-frequency heterodyne technique based on the light field. First, an underwater fisheye camera imaging model based on the light field is established to demonstrate the multiple refractions of light in underwater propagation and the extraordinary imaging characteristics of the fisheye lens, which shows better conciseness and organization. Then, the calibration method applied in the underwater fisheye camera imaging system is proposed to determine the mapping of the light field and the pose of the underwater fisheye camera. The light field mapping of the fisheye lens is obtained with the assistance of the multi-frequency heterodyne technique. Finally, an underwater fisheye camera is developed and the experimental results are obtained to validate the correctness and feasibility of the proposed method. Our underwater imaging system proves capable of achieving higher accuracy in the context of underwater 3D measurement.
Multiphase-field modeling of temperature-driven intermetallic compound evolution in an Al–Mg system for application to solid-state joining processes
Authors: Raza Syed Hasan , Klusemann Benjamin
Published: July 2020

Solid-state joining of dissimilar materials results typically in the formation of intermetallic compounds at the weld interface, which strongly determines the resulting mechanical properties. To tailor the joint strength, understanding of the formation of the intermetallic compound and their driving mechanisms is crucial. In this study, the evolution of temperature-driven Al3Mg2 and Al12Mg17 intermetallic compounds in an Al–Mg system for application to solid-state joining processes via a multiphase-field approach is numerically investigated. To this end, the CALPHAD approach to obtain the thermodynamic parameters of the relevant phases is used in conjunction with the multiphase-field model. The simulation results are qualitatively compared with experimental results in the literature in terms of thickness and morphology of intermetallic grains, exhibiting a reasonable agreement. The influence of grain boundary diffusion and interface energy on the morphology and kinetics of the intermetallic compound grains is investigated in detail with the established multiphase-field model.
Reduction of fibrous encapsulation by polyethylene glycol-grafted liposomes containing phosphatidylserine
Authors: Kim Yongjoon , Wu Lele , Park Hee Chul , Yang Hyeong-Cheol
Published: July 2020

Biomedical implants tend to induce fibrous encapsulation which can cause malfunction of devices and local discomfort of patients. The purpose of this study was to reduce foreign body-induced fibrous capsule formation by immunomodulation of macrophages. Polyethylene-glycol-grafted liposomes containing phosphatidylserine (PEG-PSLs) were used to modulate macrophages. Mixed cellulose ester (MCE) membranes coated with a PEG-PSLs-entrapped alginate-gelatin matrix were subcutaneously implanted into rats, and the thickness of the fibrous capsule around each MCE membrane was analyzed after four weeks. PEG-PSLs significantly reduced fibrous capsule thickness, while liposomes containing phosphatidylserine (PSLs) did not affect fibrosis. In in vitro assays, PEG-PSLs suppressed TGF-β1 secretion and multinucleated giant cell (MGC) formation in IL-4-treated RAW 264.7, a murine macrophage cell line. Although PSLs inhibited MGC formation, they exerted no effect on the secretion of TGF- β1, which is known to be an important factor in tissue fibrosis. Therefore, our results suggest that PEG-PSLs reduce fibrous capsule formation by mediating the suppression of TGF-β1 secretion from macrophages.
Salient difference of sea surface temperature over the North Atlantic in the spring following three super El Niño events
Authors: Yu Jinhua , Zhang Xuyu , Li Laurent , Shi Chunhua , Ye Yangbo
Published: July 2020

Despite similar evolution of Niño3.4 index for three strong El Niño events in the tropical Pacific in 1982–1983, 1997–1998 and 2015–2016, divergent sea surface temperature anomalies (SSTAs) were observed in the North Atlantic (NA) in spring following El Niño peak. Strong teleconnection occurred for the first two events in 1982–1983 and 1997–1998, leading to a negative phase of a North Atlantic Oscillation-like circulation over the extratropical NA, and thus a positive tripolar SSTA pattern in the NA. But the teleconnection was weak for the case of 2015–2016 El Niño, the SSTA in spring 2016 in NA being mainly created and maintained by the preconditioning of the NA basin and local atmosphere-ocean interactions. The salient difference among the three events resides in their ways to operate the teleconnection linking the central-eastern equatorial Pacific and the subtropical eastern North Pacific to the extratropical NA, which would be a key to explain the different impacts of the three exceptional El Niño events. It is furthermore shown that the reduced anomalous westerlies over Central America along 30° N around the peak time of 2015–2016 El Niño play a role of inhibition for an efficient Rossby wave energy propagation from the tropics, eastward into the Gulf of Mexico and northward into midlatitudes in the western NA.
Scale-dependency of Arctic ecosystem properties revealed by UAV
Authors: Siewert Matthias B , Olofsson Johan
Published: July 2020

In the face of climate change, it is important to estimate changes in key ecosystem properties such as plant biomass and gross primary productivity (GPP). Ground truth estimates and especially experiments are performed at small spatial scales (0.01–1 m2) and scaled up using coarse scale satellite remote sensing products. This will lead to a scaling bias for non-linearly related properties in heterogeneous environments when the relationships are not developed at the same spatial scale as the remote sensing products. We show that unmanned aerial vehicles (UAVs) can reliably measure normalized difference vegetation index (NDVI) at centimeter resolution even in highly heterogeneous Arctic tundra terrain. This reveals that this scaling bias increases most at very fine resolution, but UAVs can overcome this by generating remote sensing products at the same scales as ecological changes occur. Using ground truth data generated at 0.0625 m2 and 1 m2 with Landsat 30 m scale satellite imagery the resulting underestimation is large (8.9%–17.0% for biomass and 5.0%–9.7% for GPP600) and of a magnitude comparable to the expected effects of decades of climate change. Methods to correct this upscaling bias exist but rely on sub-pixel information. Our data shows that this scale-dependency will vary strongly between areas and across seasons, making it hard to derive generalized functions compensating for it. This is particularly relevant to Arctic greening with a predominantly heterogeneous land cover, strong seasonality and much experimental research at sub-meter scale, but also applies to other heterogeneous landscapes. These results demonstrate the value of UAVs for satellite validation. UAVs can bridge between plot scale used in ecological field investigations and coarse scale in satellite monitoring relevant for Earth System Models. Since future climate changes are expected to alter landscape heterogeneity, seasonally updated UAV imagery will be an essential tool to correctly predict landscape-scale changes in ecosystem properties.
Vibratory feeders with elongated conveying surface in rehandling of mined rock in open pit mines
Authors: Levenson S Ya , Lantsevich MA
Published: July 2020

Deep-level mining in open pits involves increased volumes of overburden. It is difficult to operate heavy-duty dump trucks at bottom levels of deep open pit mines due to limited size of working areas and high angles of roads. In this case, it is expedient to use more maneuverable crawler dumps or articulated dump trucks of comparatively low capacity and to rehandle mined rocks to larger capacity dump truck at bin trestles with forced discharge constructed on accumulation horizons. This article discusses mined rock discharge from an accumulating bin of the rehandling point by a set of vibratory feeders representing the bottom of the bin. These vibratory feeders are to provide reliable operation under high static and dynamic loads.
Ensuring self-synchronization of unbalanced vibration exciters for transveyers of overburden spreaders
Authors: Levenson S Ya , Kulikova EG
Published: July 2020

Deep-level mining in open pits involves increased volumes of overburden. It is difficult to operate heavy-duty dump trucks at bottom levels of deep open pit mines due to limited size of working areas and high angles of roads. In this case, it is expedient to use more maneuverable crawler dumps or articulated dump trucks of comparatively low capacity and to rehandle mined rocks to larger capacity dump truck at bin trestles with forced discharge constructed on accumulation horizons. This article discusses mined rock discharge from an accumulating bin of the rehandling point by a set of vibratory feeders representing the bottom of the bin. These vibratory feeders are to provide reliable operation under high static and dynamic loads.
Extraction of ore reserves from undermined protective pillar under open pit bottom
Authors: Konurin AI , Shchukin SA , Neverov SA
Published: July 2020

One of the problems in ore mining is untimely preparation of ore reserves for extraction. Eventually, mining efficiency drops. Aiming to replenish quickly depleting reserves, mining of various-purpose pillars is undertaken. For this reason, studies into safe mining of pillars are relevant and essential. For instance, for a gold mine in ground conditions of pronounced geological and structural uncertainty, for the sustained short- and-medium-term production, a method was validated and proposed for extraction of ore reserves from the undermined crown pillar left under the open pit bottom. In the framework of this research, a geomechanical model of an ore deposit has been developed in the form of a conceptual flow chart of mining of a crown pillar under an open pit bottom at the preserved production infrastructure condition by surface and underground mining. 3D numerical modeling uses the finite element method. The calculations find that underground mining of the undermined protective pillar under the open pit bottom, due to considerable jointing of the steeply dipping ore body, is limited by expansion of wide possible rock damaged zones up to the ground surface.
Specific of stress behavior in enclosing rock mass around underground structures during construction of waterworks
Authors: Gakhova LN
Published: July 2020

By the numerical stress–strain analysis using the method of boundary integral equations and the model of linearly deformable quasi-isotropic model of a layered rock mass has found the nature, mechanisms and specifics of stress state distribution in enclosing rock mass around the powerhouse hall and transformer room of the Rogunskaya Hydroelectric Plant. The influence of stage-wise face tunneling of the powerhouse hall on the elastic convergence between the bottom and roof of the hall as well as on the inelastic deformation of adjacent rock mass is assessed.
Two cases of post-limit deformation of rock mass surrounding underground opening
Authors: Chanyshev AI , Abdulin IM
Published: July 2020

The authors analyze stress state of rock mass around an underground opening in two cases of post-limit plane-strain deformation: when the modulus of compression is much higher than the modulus of post-limit deformation and when the modulus of post-limit deformation is much higher than the modulus of compression. In the first case, the damage zone sizes are obtained depending ultimate elastic strains and strength of rocks. In the second case, the solution in the rock damage zone differs from the traditional elastoplastic solutions by the increase in the maximum shear strength with distance from the boundary of underground opening.
Methods to create slots–stress raisers in near-wellbore zone
Authors: Rubtsova EV
Published: July 2020

The author reviews methods and tools for cutting slots–stress raisers in drill hole walls for directional hydraulic fracturing. Based on the review, the classification is proposed for the known tools by the method of initiating slotting: mechanical cutting; indentation of hard indenters; percussion effect by a plastic substance; blasting of jet charges. By the number of the patented engineering solutions and the level of implementation, the most popular technique is mechanical cutting. The known tools only ensure creation of slots–stress raisers in soft and medium-hard rocks. It is required to continue studies and to develop new methods and tools for cutting initiating slots for the directional hydraulic fracturing in solid ore.
Thermal effect on tilt sensor readings in the inclinometer survey system
Authors: Baryshnikov DV , Kachalsky VG
Published: July 2020

The change of the tilt sensor readings under temperature variation inside the probe in the inclinometer survey system is estimated by experiment. The analysis of the lab test results yields the temperature dependence of the readings on tilt angles.
Antenna assembly for down-the-hole measuring probe for locating and sizing hydraulic fracturing cracks in rock mass
Authors: Khmelinin AP , Konurin AI , Khmelinin DP , Konurina MI
Published: July 2020

The authors discuss the problem connected with the assessment of hydraulic fracturing quality in oil-filled formations by means of location and sizing of hydrofractures. The proposed engineering solution is to design a down-the-hole measuring probe based on the ground penetrating radar method in the range of microwaves. The authors select the model and mode of an antenna assembly for the down-the-hole probe. The width of the the major maximum of the antenna assembly pattern is determined.
Mechanical effort of ceramic particle-reinforced epoxy matrix used as a sealing layer on aluminum coatings by Arco Spray
Authors: Vergara E E , Castellanos L M , Diaz L M , Lucas A R , De Avila B B
Published: July 2020

The coating against the corrosion and wear of carbon steel with pure aluminum applied by thermal projection with electric arc (arc spray) presents a porous surface. This is the reason why adding a sealing with a polymer layer, regularly epoxy is necessary. However, epoxy-based sealing solutions usually do not have high performance against abrasive wear. In this research a new product has been developed in composite material with polymer matrix (PMCs), epoxy paint reinforced with ceramic particles, in order to improve the performance of this layer against abrasive wear. Preliminary runs were made with 3 variables: Epoxy matrix (2 types: epoxy S and epoxy C); Size of reinforcing ceramic particles (two levels: 1 μm 9 μm) and percentage of ceramic reinforcement (4 levels: 0%, 20 %, 33.3% and 50 %). Adhesion and abrasive wear tests were performed to show that the composite material with epoxy matrix type C, has better performance than the composite material with epoxy matrix type S. Increasing the percentage of reinforcement particles showed that the composite material with type C epoxy matrix maintained high levels of adhesion to the aluminum layer and showed an increase in abrasive wear resistance by about 60% compared to the resin without reinforcements.
The Innovation of Interlock Bricks with A Mixture of Bagasse Ash Without Combustion
Authors: Erwanto Z , Pranowo D D , Holik A , Amin M S , Darmawan F
Published: July 2020

Nowadays, the wall building material is dominated by clay brick and the process requires combustion. Therefore, the need for the development of interlock brick to introduce wall material that is easy to install, strong, without combustion and environmentally friendly. The shape design of interlock brick is made with Modified Tanzanian Interlock Brick (MTIB). Interlock brick size is 25.1 × 12.6 × 7.8 cm. The method of brick making with the experiments of various variations of the mixture to know the product specifications of suction, absorption, salt content and compressive strength with a quality target of grade 50 kg/cm2 that qualified SNI 15-2094-2000. The result was an MTIB that meet the requirements of SNI in a mixture with a ratio of 2 Clay: 3 Sand: 3.5 Portland Cement: 1.5 Bagasse Ash. Specifications of MTIB product obtained results compressive strength of 63.78 kg/cm2, absorption of 19%, the salt content of 4.14%, volume weight of 1.549 g/cm3 and a specific gravity of 1.81 and water suction power of 57.34 g/dm2/minute. MTIB innovations made from the waste of bagasse ash and without combustion process could be utilized for efficient civil building construction, fast, economical, and environmentally friendly compared with other brick materials.
Effects of strain rate due to SMAW welding on mechanical properties of AISI 1005 low alloy steel
Authors: Husaini  , Akbary K , Hasanuddin I , Putra T E , Husin H
Published: July 2020

The welding process can affect the mechanical properties of the metal. This study was aimed at examining the effects of welding on the strain rate of AISI 1005 carbon steel. Shield metal arc welding, utilizing an E6013 electrode with a diameter of 2.5 mm, a double V-notch with an angle of 120°, and a welding position of 1G, was used to weld low carbon steel. A tensile test was performed to determine the mechanical properties of the steel at various strain rates to represent the loads that it would be subjected to. The test was performed at strain rates of 3 mm/min, 9 mm/min, 15 mm/min and 20 mm/min. The results showed that as the strain rate of steel increased to 20 mm/min, the maximum tensile strength of 447.67 MPa and highest yield strength of 362.94 MPa were obtained, while the lowest values were obtained at a strain rate of 3 mm/min. An examination of the fractured surfaces using SEM showed that at the strain rates of 3 mm/min, 15 mm/min and 20 mm/min smaller voids were formed.
Different Techniques of Solar Rooftop Combo-PV/T System Implementation: Materials and Installations
Authors: Suryati  , Safitri Nelly , Misriana  , Mellyssa Widdha
Published: July 2020

Sun radiation been utilized to produce clean and environmental-friendly solar energy. Beside has been used as heat energy, it also has been used as electricity. Solar photovoltaic and thermal (PV/T) collector is a combo system that utilize solar PV technology and solar heater technology all together in one simply module. At the time PV system is irradiated with solar energy, the cell temperature increases significantly. As the heat that extracted is passing through a heat extracting fluid in such way under the module, then this heat is transferred become hot air and water. This paper aims to reveal several materials that been used to design solar combo-PV/T collector modules and their gains and drawbacks, and the installation onto households’ rooftops. Water-based and nanofluids-based PV/T modules are two technologies that being considered in this paper. All the comparisons that have been made turned out to match the assumption that the greater the difference of temperature between ambient temperature and temperature of the cells of the module, the less efficient the electrical efficiency and electrical output of the PV module and also to overcome the problem of low thermal conductivity. The considered water-nanofluids PV/T solar collector modules then put into account for better performance to improve the raised problem of thermal conductivity.
Synthesis and Characterization of Pd-Cu-Zr/Alumina Composite Membrane Using Surfactant-Induced Electroless Plating Technique
Authors: Sari Ratna , Dewi Ratni , Hakim Lukman
Published: July 2020

The Pd-based membranes consisting of Pd, PdCu and PdCuZr on alumina were prepared by surfactant-induced electroless plating technique. Characterization of these membranes were carried out using X-ray Diffraction (XRD, Shimadzu XRD-7000) for microstructure, Differential Scanning Calorimetry (DSC) and Thermal Gravimetric Analysis (TGA) (Shidmazu DSC/TGA-60) for thermal behavior. Considering TGA result, the PdCuZr/alumina membrane has weight loss from 10 to 9.93 mg (99.3 % residue) at 50-600°C. DSC graph of the PdCuZr/alumina membrane showed that some changes in the number exothemic/endothermic peaks. It endothermic peak was at 399 °C.
A Laboratory Scale Synthesis of Ethanol from Agricultural Waste as Bio-based Solvent for Waxy-Paraffinic Crude Oil Mitigation
Authors: Afdhol M K , Hidayat F , Abdurrahman M , Husna U Z , Sari N P , Wijaya R K
Published: July 2020

Paraffin is a problem commonly faced in petroleum production. The presence of paraffin can inhibit the process of oil flow. Mitigation methods commonly used to overcome this problem is by using chemical injection, which is solvent. In this research, a laboratory experiment was conducted to make bioethanol from agricultural waste that are rice husks and corn cobs. This bioethanol functions as a solvent that is used to reduce the pour point in a waxy-paraffinic crude oil sample. Oil samples were mixed with bioethanol with different mixing ratios, including 5%, 10%, 15%, 20% 50%. The results showed that the alcohol content of the Husk and Corncob rise was 11% and 9% respectively. Then, the best result from mixing of bioethanol with oil reduced the pour point from 43.3 to 41 at mixing ratio of 50%.
Generation of Q-switched Erbium-Doped Fiber Laser Using Titanium Dioxide Film Based Saturable Absorber
Authors: Ahmed N , Kamarulzaman NH , Zulkipli NF , Jusoh Z , Rahman HA , Harun SW
Published: July 2020

This work demonstrates a generation of a passively Q-switched erbium-doped fiber laser with titanium dioxide (TiO2) film as saturable absorber. The film is fabricated using a ratio of 2:1 by embedding the rutile nanoparticles (TiO2) into a polyvinyl alcohol (PVA) host film. Short after placing the SA film on the fiber ferrule, a stable 1563.3 nm pulses appeared at a power pump range from 104.62 mW to 145.83 mW. The maximum output power was recorded at 2.05 mW, inducing a maximum pulse energy of 22.63 nJ. The repetition rate shows an increasing trendline from 81.04 kHz to 90.58 kHz while the pulse width decreases from 5.08 μs to 4.12 μs. The high signal to noise ratio (SNR) of 63 dB indicates that the TiO2 film has a good performance in generating pulsed laser at 1550 nm wavelength.
Passively Q-switched Erbium-doped Fiber Laser using Tungsten Disulfide deposited D-shaped Fiber as Saturable Absorber
Authors: Omar S , Musa B , Jusoh Z , Ali MIM , Jafry AAA , Harun SW
Published: July 2020

This paper generates a stable Q-switching output wavelength 1560 nm by utilizing tungsten disulfide (WS2) as saturable absorber on D-shaped fiber in erbium-doped fiber laser. D-shaped fiber was prepared by using polishing wheel technique with rough and fine polishing is conducted to ensure efficient light-matter interaction inside D-shaped optical fibre. Proposed Q-switched erbium-doped fiber laser generates shortest pulse duration of 3.25 μs with repetition rate of 108.90 kHz. Q-switched generated was stable under pump power of 84.02 mW to 182.92 mW. Obtaining signal-to-noise ratio of 40.58 dB, Q-switched induced contain pulse energy of 14.60 nJ with output power of 0.64 mW to 1.59 mW. Therefore, proposed D-shaped fiber-WS2as saturable absorber was stable and efficient for making a portable laser source based on Q-switched.
Thermal Transport Feasibility of (Water + Ethylene Glycol)-Based Nanofluids Containing Metallic Oxides: Mathematical Approach
Authors: Alawi Omer A , Mallah A R , Kazi S N , Zubir M N M , Oon C S
Published: July 2020

A mathematical approach was used to predict the heat transfer performance of CuO nanoparticles with three different filling ratios [DW], [DW70:30EG] and [DW50:50EG]. There was a discussion on the thermophysical properties. Thermal diffusivity, Prandtl member and pumping power were predicted to find the optimal filling ratio. The effect of nanoparticle shapes on the thermal conductivity and dynamic viscosity was examined. The base fluid of [DW50:50EG] showed significant improvement while DW was optimal for thermal conductivity. Higher thermal conductivity was achieved by DW-based spherical nanofluids, while [DW50:50EG]-based platelets nanofluid showed the best improvement in dynamic viscosity. By increasing the temperature, thermal diffusivity increased while the Prandtl number decreased. The loading of nanofluids did not require more power consumption, and the relative pumping power was less than 1.
Microsecond Pulse Generation using Bismuth Salenide as Saturable Absorber in 1.5 μm Region
Authors: Yusoff R A M , Jafry A A A , Zulkipli N F , Kasim N , Rifin S N M , Munajat Y , Harun S W
Published: July 2020

A Q-switched Erbium-doped fiber laser (EDFL) was demonstrated utilizing Bismuth Salenide (Bi
2
Se
3) as a saturable absorber. The saturable absorber (SA) is fabricated by mixing directly the Bismuth Salenide (Bi
2
Se
3) into polyvinyl alcohol (PVA) aqueous solution to form a thin film. The SA is integrated into EDFL cavity to achieve a stable Q-switched at center wavelength of 1559.8 nm. The peak power is a steady increasing pattern from 2.52 mW to 3.21 mW as the pump power is increased from 86.1 mW to 116.6 mW. The highest pulse energy obtained was 36.9 nJ at the pump power of 116.6 mW.
Effect of Addition of Chitosan-ZnO as an Antibacterial on The Thermal Stability of PLA-Based Nanocomposites for Biofilm Packaging
Authors: Rihayat T , Riskina S , Nurhanifa  , Syahyadi R
Published: July 2020

This research is about Composite Polylactic Acid with chitosan and zinc oxide reinforcement (ZnO) in the manufacture of packaging biofilms. The purpose of this study is to produce biofilms with good characteristics that can be applied to food packaging. The method used is heating by varying the concentration of chitosan (1, 3 and 6%) and the concentration of ZnO at (1,2,3 and 4%). The resulting biofilm was analyzed by tensile test, thermal gravimetric, and FTIR. The results showed that the optimum tensile strength value obtained at the addition of Chitosan 6% - ZnO 3%, amounting to 1.22 MPa. The functional groups contained with the addition of ZnO and chitosan are functional groups C-H, C = O, O-H, and N-H. Biofilm samples underwent single decomposition with biofilm degradation temperatures ranging from 220-300 °C, the highest On Set temperature was 238.24°C, while the highest End Set was 295.16 °C. ZnO reinforcement added to the resulting composite can increase the tensile strength.