bluuebunny/crossref_metadata_2025 huggingface dataset:
Correction: Local synergetic collaboration between Pd and local tetrahedral symmetric Ni oxide enables ultra-high-performance CO2 thermal methanation
Authors: Yan Che , Wang Chia-Hsin , Lin Moore , Bhalothia Dinesh , Yang Shou-Shiun , Fan Gang-Jei , Wang Jia-Lin , Chan Ting-Shan , Wang Yao-lin , Tu Xin , Dai Sheng , Wang Kuan-Wen , He Jr-Hau , Chen Tsan-Yao
Published: September 2020

Correction for ‘Local synergetic collaboration between Pd and local tetrahedral symmetric Ni oxide enables ultra-high-performance CO2 thermal methanation’ by Che Yan et al., J. Mater. Chem. A, 2020, 8, 12744–12756, DOI: 10.1039/D0TA02957B.
High triplet energy bipolar host materials with the combination of dibenzofuran and benziimidazobenzoimidazole moieties for blue thermally activated delayed fluorescence emitter
Authors: Youn Kyu Man , Lee Hyuna , Yoo Han Jong , Jung Young Hun , Park Jae Do , Jeong Hyein , Lee Jungsub , Lee Ju Young , Kwon Jang Hyuk
Published: September 2020

Two bipolar host materials were designed and synthesized for blue thermally activated delayed fluorescence (TADF) OLEDs.
Role of interfacial 2D graphene in high performance 3D graphene/germanium Schottky junction humidity sensors
Authors: Zhao Menghan , Zhu Wei , Feng Xiaoqiang , Yang Siwei , Liu Zhiduo , Tang Shiwei , Chen Da , Guo Qinglei , Wang Gang , Ding Guqiao
Published: September 2020

The 3D/2D-Gr/Ge architecture has excellent Schottky junction-based humidity sensing characteristics with fast response rate and recovery time due to its enhanced thermal/electrical conductivity without several post-transfer processing steps being required during fabrication.
Synthesis of new pyrazolone and pyrazole-based adamantyl chalcones and antimicrobial activity
Authors: Al-Saheb Rawan , Makharza Sami , Al-battah Feras , Abu-El-Halawa Rajab , Kaimari Tawfeq , Abu Abed Omar S.
Published: September 2020

Chalcones and their derivatives are becoming increasingly popular due to their various pharmacological effects. Chalcone molecules may be extracted from natural resources, entirely synthesised, or biosynthesised by modifying the natural ones. In the present study, five pyrazole-based adamantyl heterocyclic compounds were synthesised by condensation of 1-adamantyl chalcone with substituted phenylhydrazine. The products were characterised by using ¹H NMR, ¹³C NMR and FT-IR spectroscopy. The microbiological activity of these compounds was investigated against bacteria and fungi. The new compounds showed good to moderate activity against the microbial species used for screening. All developed molecules showed antibacterial activity against Gram-negative and Gram-positive. These molecules showed antifungal activities against Fusarium oxysporum fungus and in a dose-dependent manner, apart from RS-1 molecules which showed compromised antifungal activity and even at a high dose.
Robust output‐regulation for uncertain linear systems with input saturation
Authors: Gutiérrez Ariana , Ríos Héctor , Mera Manuel
Published: September 2020

The aim of this study is to design a robust output‐based control to regulate the output for a class of linear systems with input saturation and affected by parameter uncertainties and external disturbances. The proposed robust control approach is composed of a homogeneous observer and a linear control law. The design and convergence analysis of the homogeneous observer is based on the implicit Lyapunov function theorem guaranteeing the finite‐time convergence of the state estimation error to a neighbourhood of the origin. The linear control law, that uses the estimated states and takes into account the saturated input constraint, is designed based on the attractive ellipsoid method and a barrier Lyapunov function approach. The synthesis of the robust‐output based control is given in terms of linear matrix inequalities. Simulation results are presented to illustrate the feasibility of the proposed robust control approach.
Vieira Natividade Experimental Plots at Mata Nacional do Vimeiro, Portugal
Authors: Carrasquinho Isabel , Nóbrega Filomena , Gonçalves Jorge , Costeira Isabel
Published: September 2020

In 1933, Joaquim Vieira Natividade established an experimental field with oaks and related genera at Mata Nacional do Vimeiro, Portugal. This experimental area includes the only Portuguese plots with the hybrid Quercus x hispanica hybrid ‘Lucombeana’ (Quercus cerris x suber) with seeds obtained from the Cambridge Botanic Gardens.In 1962-1965, their offspring were included in this area.

Those plots integrate an ex situ forest genetic resources, representing a unique population for understanding the structure, function and evolution of the genome (genomics) and its gene expression (transcriptomics). In all progenies, with approximately 60 years, it is evident the segregation for several phenotypic characteristics, specifically in the cork formation and in the leaf shape. Based on that, two projects were developed with this plant material. The first was focused on finding out the molecular basis responsible for the variation in cork and the other on association genetic studies.

The aim of this work is to allow access and sharing of knowledge about this genetic material in accordance with the established by FAO in the State of the World’s Forest Genetic Resources report. Information about these hybridsis available at PANGAEA repository.
A Log-Ratio Vegetation Index (LRVI) for Discrimination and Classification of Remote Sensing Data
Authors: Rego Francisco C. , Cadima Irene S.P. , Strand Eva K.
Published: September 2020

Discrimination and classification are integral processes for interpreting remotely sensed data. Many spectral vegetation indices have been proposed for discriminating between vegetation, soil, and other ground cover categories. Classical remote sensing show that reflectance in the red (R) and near infrared (NIR) bands of the electromagnetic spectrum have been successful in differentiating between vegetation and other ground cover classes and they are commonly used for this purpose. Here we demonstrate how Fisher’s classical statistics can be applied to develop discriminant functions for commonly used vegetation indices simply using the R and NIR bands. We derive a new vegetation index, the Log-Ratio Vegetation Index (LRVI) and demonstrate its utility in discriminating between cork oak trees and surrounding background in woodlands in Portugal. The LRVI performed better than seven previously developed vegetation indices, likely because of its linear properties in the reflectance density spectral space. The robustness and simplicity of LRVI suggests that it deserves further exploration and should be included for comparison with other vegetation indices and functions in discrimination, classification, and modelling studies. We suggest that the demonstrated approach is widely applicable to development of indices composed of other bands than R and NIR for systems or processes that correlate better with reflectance in other regions of the electromagnetic spectrum.
A numerical model of elasticity for cardiovascular system that includes 2/3D displacements and deformations
Authors: Azzayani Ayoub
Published: September 2020

In this work, we deal an elasticity model in 2D and 3D dimension for deformation under constraint by taking into account the direction of the deformation displacement. This work is a result of an article [A. Azzayani et al., Br. J. Math. Comput. Sci. (2016)] in which we use the same mathematical model by fixing the fiber orientation. Then, if we considered the case of eignvalue and eigenvector, and which is the case of this work, we can be able to control the deformation of the heart in the image processing. This mathematical model can be used to describe the heart deformation taking into account the orientation of the fibers for estimating global and regional parameters of the left ventricular function. In first, we start by presenting the proposed mathematical model on a domain Ω ⊂ ℝn (n = 2 or 3), and we give the existence and uniqueness of solution to the mathematical model is given (in both 2D and 3D dimension). Secondly, we give numerical simulations with FreeFem software, simulations results and comments are given in the end. In the end, we will discuss about the image treatment with this model and its feasibility to help doctors in the diagnosis of heart disease.
LUCI onboard Lagrange, the next generation of EUV space weather monitoring
Authors: West Matthew J. , Kintziger Christian , Haberreiter Margit , Gyo Manfred , Berghmans David , Gissot Samuel , Büchel Valeria , Golub Leon , Shestov Sergei , Davies Jackie A.
Published: September 2020

Lagrange eUv Coronal Imager (LUCI) is a solar imager in the Extreme UltraViolet (EUV) that is being developed as part of the Lagrange mission, a mission designed to be positioned at the L5 Lagrangian point to monitor space weather from its source on the Sun, through the heliosphere, to the Earth. LUCI will use an off-axis two mirror design equipped with an EUV enhanced active pixel sensor. This type of detector has advantages that promise to be very beneficial for monitoring the source of space weather in the EUV. LUCI will also have a novel off-axis wide field-of-view, designed to observe the solar disk, the lower corona, and the extended solar atmosphere close to the Sun–Earth line. LUCI will provide solar coronal images at a 2–3 min cadence in a pass-band centred on 19.5. Observations made through this pass-band allow for the detection and monitoring of semi-static coronal structures such as coronal holes, prominences, and active regions; as well as transient phenomena such as solar flares, limb coronal mass ejections (CMEs), EUV waves, and coronal dimmings. The LUCI data will complement EUV solar observations provided by instruments located along the Sun–Earth line such as PROBA2-SWAP, SUVI-GOES and SDO-AIA, as well as provide unique observations to improve space weather forecasts. Together with a suite of other remote-sensing and in-situ instruments onboard Lagrange, LUCI will provide science quality operational observations for space weather monitoring.
Psychotherapie in der interdisziplinären multimodalen Schmerztherapie: Update
Authors: Müller Maike , Bräscher Anne-Kathrin
Published: September 2020

Psychotherapie bei chronischen Schmerzen? Was auf den ersten Blick unpassend erscheint, entpuppt sich als hilfreiche und wirksame Intervention für Störungsbilder, bei denen rein somatisch orientierte Behandlungsversuche scheitern. Eingebettet in die interdisziplinäre multimodale Schmerztherapie stellt die Schmerzpsychotherapie heutzutage einen essenziellen Bestandteil der Behandlung chronischer Schmerzen dar.
Hyperfibrinolyse nach Reanimation bei akuter Lungenarterienembolie
Authors: Weber Christian F. , Wesselly Ariane , Held Thomas , Anheuser Petra , Schönwälder Jürgen , Weischer Willem
Published: September 2020

Kommt es nach einer Reanimation – z. B. wegen akuter Lungenarterienembolie – im Rahmen eines Post-Cardiac-Arrest-Syndroms (PCAS) zu einer Hyperfibrinolyse, stellt dies eine diagnostische und therapeutische Herausforderung dar. In diesem Fallbericht wird die Pathophysiologie der Koagulopathie bei PCAS beschrieben und der Einsatz antifibrinolytischer Therapie bei Patienten mit thrombotischen Komplikationen wie Lungenarterienembolien diskutiert.
In Silico Hemostasis Modeling and Prediction
Authors: Nechipurenko Dmitry Y. , Shibeko Aleksey M. , Sveshnikova Anastasia N. , Panteleev Mikhail A.
Published: September 2020

Computational physiology, i.e., reproduction of physiological (and, by extension, pathophysiological) processes in silico, could be considered one of the major goals in computational biology. One might use computers to simulate molecular interactions, enzyme kinetics, gene expression, or whole networks of biochemical reactions, but it is (patho)physiological meaning that is usually the meaningful goal of the research even when a single enzyme is its subject. Although exponential rise in the use of computational and mathematical models in the field of hemostasis and thrombosis began in the 1980s (first for blood coagulation, then for platelet adhesion, and finally for platelet signal transduction), the majority of their successful applications are still focused on simulating the elements of the hemostatic system rather than the total (patho)physiological response in situ. Here we discuss the state of the art, the state of the progress toward the efficient “virtual thrombus formation,” and what one can already get from the existing models.
Does Rabeprazole Sodium Alleviate the Anti-diabetic Activity of
Linagliptin? Drug-Drug Interaction Analysis by In vitro and In vivo
Methods
Authors: Hossain Md. Jamal , Sultan Md. Zakir , Rashid Mohammad A. , Kuddus Md. Ruhul
Published: September 2020

Drug interaction has turned into the preeminent regarding issues for a prescriber
during polypharmacy. The foremost objective of this research was to form a
complex between linagliptin and rabeprazole sodium by in vitro
interactions. The interactions between the drugs have been examined by
monitoring some chromatographic and spectroscopic analyses viz. TLC, HPLC,
FT-IR, UV, Job’s plot, conductometric titrations, and Ardon’s
spectrophotometric strategy. Rabeprazole sodium formed a stable complex with
linagliptin, which was ensured from the insight of these analytical data. The
developed complex’s bright spot was clearly watched in the TLC plate.
The retention time (Rt) of the formed complex was 5.303 min,
where the Rt were 3.364 and 3.103 min for linagliptin and
rabeprazole sodium, respectively, in HPLC chromatograms. In FT-IR and UV spectra
of the formed complex revealed some disappearance of characteristic peaks that
affirmed the complexation. All of the variations of the spectrophotometric and
chromatographic properties from the antecedent drugs indicated the drug-drug
interaction. Another crucial fact for the experimental aim was to affirm the
assumed drug interaction by in vivo model examination. The assessment of
anti-diabetic property on alloxan-induced Swiss albino mice proved significant
in vivo interaction between the drugs. It was outlined from the
animal study that the hypoglycemic activity of linagliptin might be
significantly affected due to the complex formation of the drug with a proton
pump inhibitor (PPI). Nonetheless, it is the primary outcome of the interaction,
which recommends the bigger in vivo study or clinical monitoring on the
human model.
Bouncing back, if not beyond: Challenges for research on resilience
Authors: Hoegl Martin , Hartmann Silja
Published: September 2020

Setbacks are a fact of life for individuals and collectives—and resilience is a key concept in explaining why some entities positively adapt (i.e., bounce back) or even emerge stronger (i.e., bounce beyond), while others suffer from such events, sometimes permanently. In this short note, we briefly introduce the concept of resilience before moving to three key challenges for management research in this field. With this, we would like to encourage the international scholarly research community to view any phenomenon of their interest also from a resilience perspective, considering significant setbacks and processes of positive adaptation.
Earthquake model shakes things up to uncover relationships between seismic parameters
Authors: Bandari Anashe
Published: September 2020

Observational studies of earthquake features are notoriously difficult, though data points to some potential universal relationships.
On stable quantum currents
Authors: Asch Joachim , Bourget Olivier , Joye Alain
Published: September 2020

We study the transport properties of discrete quantum dynamical systems on the lattice, in particular, coined quantum walks and the Chalker–Coddington model. We prove the existence of a non-trivial charge transport implying that the absolutely continuous spectrum covers the whole unit circle under mild assumptions. We discuss anomalous quantum charge transport. For quantum walks, we exhibit the explicit constructions of coins that imply the existence of stable directed quantum currents along classical curves. The results are of topological nature and independent of the details of the model.
On detuned 1:1:3 Hamiltonian resonance with cases of symmetric cubic and quartic potentials
Authors: Mazrooei-Sebdani Reza , Hakimi Elham
Published: September 2020

This paper deals with a normal form of Hamiltonian 1:1:3 resonance. It is not integrable, and we write it using the basic invariants. Also, we identify the coefficients of the terms that remain in the normalization procedure. Then, by choosing different potential functions, we consider three integrable subfamilies of the Hamiltonian with a discrete symmetry. They are containing a Hamiltonian in a 3D Greene case, a generalized Hénon–Heiles Hamiltonian, and a quartic Hamiltonian. We consider the detuning parameters and analyze the bifurcations.
Origin of relaxation frequency shift in blue organic light-emitting diodes
Authors: Kim Yeeun , Na Inyeob , Seo Youkyung , Chae Heeyoung , Oh Kilhwan , Yang Joonyoung , Yoon Sooyoung , Joo Min-Kyu
Published: September 2020

Recent technological innovations in organic light-emitting diodes (OLEDs) have enabled their applicability to be expanded to not only displays but also the lighting industry. In addition, the high scalability and flexibility of OLEDs render them promising candidates for next-generation displays. However, their insufficient lifetime and low uniformity/stability are challenging issues, mainly because of inadequate understanding regarding the fundamental degradation mechanism of OLEDs owing to their complex device structure. Herein, based on impedance spectroscopy (IS), we report the origin of the relaxation frequency (fR) shift in blue OLEDs as a function of electrical stress time for up to 1000 h with a constant current stress condition of 1 mA. These experimental conditions allow us to separately study the degradation mechanisms of the emission and transport layer (TPL) interfaces. On the basis of thorough understanding of the theoretical expression of fR, we mainly attribute the variation in fR at the charge-balancing voltage to the degradation of the TPL interface; this is further rationalized by the negligible difference between fR values obtained from IS and the equivalent circuit theory. This strong correlation consequently renders fR a powerful degradation indicator for the TPL interface. Our results provide a basis for the realization of highly reliable blue OLEDs with a sufficient lifetime.
Oxidation induced restructuring of Rh–Ga SCALMS model catalyst systems
Authors: Wittkämper Haiko , Maisel Sven , Wu Mingjian , Frisch Johannes , Wilks Regan G. , Grabau Mathias , Spiecker Erdmann , Bär Marcus , Görling Andreas , Steinrück Hans-Peter , Papp Christian
Published: September 2020

Supported catalytically active liquid metal solutions have been receiving increasing attention recently. We investigated the oxidation behavior of macroscopic Rh–Ga alloy droplets and Rh–Ga model catalyst nanoparticles supported on SiO2/Si(100) with low Rh content (<2.5 at. %) by x-ray photoelectron spectroscopy in ultra-high vacuum and under near-ambient pressure conditions using different photon energies and also using transmission electron microscopy. The experiments are accompanied by computational studies on the Ga oxide/Rh–Ga interface and Rh–Ga intermetallic compounds. For both Rh–Ga alloy droplets and Rh–Ga model catalyst nanoparticles, exposure to molecular oxygen leads to the formation of an oxide shell in which Rh is enriched. Transmission electron microscopy on the Rh–Ga nanoparticles confirms the formation of an ∼4 nm thick gallium oxide film containing Rh. Based on ab initio molecular dynamics and computational studies on the Ga2O3/Ga interface, it is concluded that Rh incorporation into the Ga2O3 film occurs by substituting octahedrally coordinated Ga.
Bipolar magnetostriction in CoFe2O4: Effect of sintering, measurement temperature, and prestress
Authors: Venkata Siva K. , Sudersan S. , Arockiarajan A.
Published: September 2020

Magnetostrictive materials are potential candidates for many applications such as sensors, actuators, transducers, and other magnetoelectric applications. Cobalt ferrite (CoFe2O4) has proven to be favorable in comparison with commonly used magnetostrictive materials due to its high magnetostriction coefficient and low cost. This work deals with the synthesis of CoFe2O4 and subsequent characterization of its magnetostrictive properties. Hydrothermal route was adopted for the synthesis, and the effect of sintering and measurement temperatures on the magnetostrictive response of the synthesized samples was also established. Bipolar magnetostriction has been observed in pure CoFe2O4 for the first time, and its control by means of the sintering temperature has been elucidated. The results thus reveal that the temperature is an important parameter in determining the magnetostrictive characteristics of CoFe2O4. The switching from bipolar to unipolar magnetostriction under elevated sintering and measurement temperatures was also observed, and this was owed to the crystal anisotropy of the material. The effect of prestress on the magnetostriction was also studied, wherein it was observed that the application of a compressive prestress resulted in broadening of the magnetostriction loops. The reported bipolar magnetostrictive characteristics are quite interesting and hence can prove to be cost-effective in comparison with existing magnetostrictive materials.
Regulation of hepatic insulin signaling and glucose homeostasis by sphingosine kinase 2
Authors: Aji Gulibositan , Huang Yu , Ng Mei Li , Wang Wei , Lan Tian , Li Min , Li Yufei , Chen Qi , Li Rui , Yan Sishan , Tran Collin , Burchfield James G. , Couttas Timothy A. , Chen Jinbiao , Chung Long Hoa , Liu Da , Wadham Carol , Hogg Philip J. , Gao Xin , Vadas Mathew A. , Gamble Jennifer R. , Don Anthony S. , Xia Pu , Qi Yanfei
Published: September 2020

Significance

Hepatic insulin resistance is a chief pathogenic determinant in the development of type 2 diabetes, which is often associated with abnormal hepatic lipid regulation. Sphingolipids are a class of essential lipids in the liver, where sphingosine kinase 2 (SphK2) is a key enzyme in their catabolic pathway. However, roles of SphK2 and its related sphingolipids in hepatic insulin resistance remain elusive. Here we generate liver-specific Sphk2 knockout mice, demonstrating that SphK2 in the liver is essential for insulin sensitivity and glucose homeostasis. We also identify sphingosine as a bona fide endogenous inhibitor of hepatic insulin signaling. These findings provide physiological insights into SphK2 and sphingosine, which could be therapeutic targets for the management of insulin resistance and diabetes.
Proline-rich domain of human ALIX contains multiple TSG101-UEV interaction sites and forms phosphorylation-mediated reversible amyloids
Authors: Elias Ruben D. , Ma Wen , Ghirlando Rodolfo , Schwieters Charles D. , Reddy Vijay S. , Deshmukh Lalit
Published: September 2020

Significance

Human ALIX is involved in many essential cellular processes. The carboxy (C)-terminal proline-rich domain (PRD) of ALIX, which interacts with multiple partners, has eluded analysis owing to the presence of polyproline stretches that hinder recombinant protein production. By dividing it into two fragments, the amino (N)- and the C-terminal portions, we carry out a detailed biophysical investigation of ALIX-PRD. The disordered N-terminal fragment comprises three proline-rich motifs that compete for binding to its partner, TSG101-UEV. In contrast, the C-terminal fragment forms reversible amyloids modulated by tyrosine phosphorylation, the first known example where posttranslational modifications dictate the dissolution of amyloid fibrils. This study illustrates the mechanistic interdependence of multivalency brought out by polymerization of ALIX-PRD and its effect on ALIX function.
FIT2 is an acyl–coenzyme A diphosphatase crucial for endoplasmic reticulum homeostasis
Authors: Becuwe Michel , Bond Laura M. , Pinto Antonio F.M. , Boland Sebastian , Mejhert Niklas , Elliott Shane D. , Cicconet Marcelo , Graham Morven M. , Liu Xinran N. , Ilkayeva Olga , Saghatelian Alan , Walther Tobias C. , Farese Robert V.
Published: September 2020

The endoplasmic reticulum is a cellular hub of lipid metabolism, coordinating lipid synthesis with continuous changes in metabolic flux. Maintaining ER lipid homeostasis despite these fluctuations is crucial to cell function and viability. Here, we identify a novel mechanism that is crucial for normal ER lipid metabolism and protects the ER from dysfunction. We identify the molecular function of the evolutionarily conserved ER protein FIT2 as a fatty acyl–coenzyme A (CoA) diphosphatase that hydrolyzes fatty acyl–CoA to yield acyl 4′-phosphopantetheine. This activity of FIT2, which is predicted to be active in the ER lumen, is required in yeast and mammalian cells for maintaining ER structure, protecting against ER stress, and enabling normal lipid storage in lipid droplets. Our findings thus solve the long-standing mystery of the molecular function of FIT2 and highlight the maintenance of optimal fatty acyl–CoA levels as key to ER homeostasis.
Non-Markovian trajectories involving future in semi-classical path integral expression
Authors: Wang Fei
Published: September 2020

Semi-classical path integral expression for a quantum system coupled to a harmonic bath is derived based on the stationary phase condition. It is discovered that the system path is non-Markovian. Most strikingly, the system path not only couples to its past, but also to its future, i.e. the equation of motion for the system is an integro-differential equation that involves all times. Numerical examples are given at the end. Because of the future-non-Markovian nature of the equation, the numerical solution cannot be obtained by iterative methods. Instead, root search algorithms must be employed.
The M waves of the biceps brachii have a stationary (shoulder-like) component in the first phase: implications and recommendations for M-wave analysis
Authors: Rodriguez-Falces Javier , Botter Alberto , Vieira Taian , Place Nicolas
Published: September 2020

Objective. We recently documented that compound muscle action potentials (M waves) recorded over the ‘pennate’ vastus lateralis showed a sharp deflection (named as a shoulder) in the first phase. Here, we investigated whether such a shoulder was also present in M waves evoked in a muscle with different architecture, such as the biceps brachii, with the purpose of elucidating the electrical origin of such afeature. Approach. M waves evoked by maximal single shocks to the brachial plexus were recorded in monopolar and bipolar configurations from 72 individuals using large (10 mm diameter) electrodes and from eight individuals using small (1 mm diameter) electrodes arranged in a linear array. The changes in M-wave features at different locations along the muscle fiber direction were examined. Main results. The shoulder was recognizable in most (87%) monopolar M waves, whereas it was rarely observed (6%) in bipolar derivations. Recordings made along the fiber direction showed that the shoulder was a stationary (non-propagating) feature, with short duration (spiky), which had positive polarity at all locations along the fibers. The latency of the shoulder (9.5 ± 0.5 ms) was significantly shorter than the estimated time taken for the action potentials to reach the biceps tendon (12.8 ms). Significance. The shoulder must be generated by a dipole source, i.e. a source created at a fixed anatomical position, although the exact origin of this dipole is uncertain. Our results suggest that the shoulder may not be due to the end-of-fiber signals formed at the biceps brachii tendon. The shoulder is not related to any specific arrangement of muscle fibers, as it has been observed in both pennate and fusiform muscles. Being a stationary (non-propagating) component, the shoulder is not reliable for studying changes in sarcolemmal excitability, and thus should be excluded from the M-wave analysis.
Galatea trap: magnetohydrodynamic stability of plasma surrounding current-carrying conductors
Authors: Medvedev S Yu , Martynov A A , Kozlov A N , Savelyev V V
Published: September 2020

Ideal magnetohydrodynamic (MHD) properties depending on the plasma pressure are considered for axisymmetric equilibrium magnetoplasma configurations in the Galatea trap with three ring current-carrying conductors embedded in plasma. The study of ideal MHD modes with different toroidal wave numbers takes into account the plasma compressibility with an adiabatic index of 5/3 in the perturbed potential energy functional in the framework of the energy principle. The stability calculations are performed in the presence of a vacuum layer between the plasma and the vacuum chamber. The limiting pressure values corresponding to stable multiply connected plasma configurations without an assumption of nested magnetic surfaces are estimated.
Time and space resolved diagnostics for plasma thermal-chemical instability of fuel oxidation in nanosecond plasma discharges
Authors: Rousso Aric C , Goldberg Benjamin M , Chen Timothy Y , Wu Shuqun , Dogariu Arthur , Miles Richard B , Kolemen Egemen , Ju Yiguang
Published: September 2020

An instability in a nanosecond pulsed dielectric barrier discharge plasma occurring in methane–oxygen–argon mixtures is experimentally observed and measured by 1D time-resolved in situ electric field measurements. This instability, which seems to be created by the positive feedback between plasma kinetics and plasma-assisted low temperature fuel oxidation, is studied using electric field induced second harmonic generation and direct ICCD imaging. The rapid formation of streamers from an originally uniform discharge appears to be caused by the chemical kinetics of plasma-assisted low temperature methane oxidation, which may be resulting in a new type of plasma instability: a thermal-chemical instability. The results also revealed that the occurrence of this possible thermal-chemical instability in a reactive flow drastically changes the plasma properties by forming multiple secondary discharges and possibly leads to micron-sized non-uniform electric distributions. Single shot uncalibrated measurements of the electric field of the micron sized streamers appears to show much greater strengths than the average electric field. Furthermore, one-dimensional data analysis shows the positive feedback loop between the streamers and the low temperature plasma assisted oxidation chemistry in the plasma thermal-chemical instability. The present finding advances the understanding plasma instability growth and provides a new way to control plasma uniformity in plasma-assisted combustion and plasma fuel reforming.
Kinetic Monte Carlo simulations of plasma-chemistry
Authors: Dias Tiago C , Guerra Vasco
Published: September 2020

This work presents a kinetic Monte Carlo algorithm to solve the gas-phase chemistry in low-temperature plasmas, as a first effort to achieve a unified formulation of the electron and heavy-particle kinetics based on Monte Carlo techniques. The implemented algorithm is successfully validated in the thermodynamic limit from the comparison with the traditional deterministic description using rate-balance equations. The accuracy of the Monte Carlo description of the rare species strongly depends on the number of particles used in the simulation. To surpass this limitation, two novel variance reduction techniques that significantly reduce the statistical fluctuations on the concentrations of the minor species are proposed and evaluated. These techniques lead to significant gains in computational time, up to factors of the order of 104 times in the cases studied, while ensuring the same quality of the solution.
Interannual variations of the influences of MJO on winter rainfall in southern China
Authors: Chen Xiong , Li Chongyin , Li Lifeng , Yu Peilong , Yang Minghao
Published: September 2020

The influences of Madden-Julian Oscillation (MJO) on the winter rainfall in southern China exhibit prominent interannual variations. In general, when MJO is active over the Indian Ocean (western Pacific), winter rainfall in southern China increases (decreases) substantially; however, it also decreases (increases) significantly in some winters. The anomalous atmospheric circulation, especially the intraseasonal and low-frequency circulation anomalies, like are responsible for these variations. Both the intraseasonal and low-frequency circulation anomalies are almost opposite between wetter and drier winters MJO is active over the Indian Ocean and the western Pacific, which leads to the different moisture convergences in southern China. As a result, the influences of MJO over the same region on winter rainfall in southern China are different. When MJO is active over the Indian Ocean, the moisture convergence (divergence) in wetter (drier) winters is dominated primarily by the meridional (zonal) moisture convergence (divergence) and advection. When MJO is active over the western Pacific, in both wetter and drier winters, the anomalous moisture divergence is controlled by the meridional moisture divergence and advection. Therefore, it is not only the location and intensity of MJO activity that are important; the anomalous circulation and moisture on different timescales (in particular the intraseasonal and low-frequency timescales) should be considered in the operational weather forecast when using MJO as a predictor.
Propagation of periodic wave trains along the magnetic field in a collision-free plasma
Authors: Abbas G , Kevrekidis P G , Allen J E , Koukouloyannis V , Frantzeskakis D J , Karachalios N
Published: September 2020

In this work, a systematic study, examining the propagation of periodic and solitary waves along the magnetic field in a cold collision-free plasma, is presented. Employing the quasi-neutral approximation and the conservation of momentum flux and energy flux in the frame co-traveling with the wave, the exact analytical solution of the stationary solitary pulse is found analytically in terms of particle densities, parallel and transverse velocities, as well as transverse magnetic fields. Subsequently, this solution is generalized in the form of periodic waveforms represented by cnoidal-type waves. These considerations are fully analytical in the case where the total angular momentum flux L, due to the ion and electron motion together with the contribution due to the Maxwell stresses, vanishes. A graphical representation of all associated fields is also provided.
An Evaluation of Barriers obstructing the Applicability of Standard Bidding Documents (SBDs) in Public Procurement of Iraq
Authors: Hasan Sadeq AbdulHamza , Mohammed Sawsan Rasheed
Published: September 2020

According to Order Number 87 of 2004 which had been issued by Dissolved Coalition Provisional Authority in Iraq, the Ministry of Planning MoP in the Iraqi Government started its efforts toward enhancing and developing the federal level of Public Procurement System by issuing a stream of procedures to the contractual entities (Standard Bidding Documents SBDs, procurement Planning Forms, Performance Indicators, Guide of Archiving Process… etc.). The financial crises which hit the international economy and the noted reduction in crude oil prices and the war against ISIS on the local level reflected an obvious shortage in funding process to the implementation of the project to the very minimums. At 2018 the Iraqi government allocated more funds to compensate the shortage in initial services projects at a time when the SBDs became mandatory to apply by all the public contractual entities, as a result, the local contractors were not able to meet the standard requirements and criteria of a modern experiment in the bidding process which led to more delay by re-announcing these projects. This research is to determine if the Iraqi contractual environment can be considered as healthy and supportive for the SBDs or not? Nine evaluation criteria for the SBDs projects were listed in the questionnaire targeted 100 private sector respondents and 130 public contractual entities, the mean comparison and relative important index RII were used to rank and match respondent agreement on assessing the importance mentioned criteria evaluation. The findings indicated that all respondents had agreed on ranking the average of annual revenues and financial liquidity as the top hurdles that need to be considered by MoP to ensure the success of the SBDs system.
Dynamic Performance of Various Thermal Energy Storage Materials
Authors: Alhamdo M H , Theeb M A , Alani H S
Published: September 2020

The thermal effects of metal partitions inside Porous Thermal Energy Storage (PTES) have been investigated experimentally and theoretically. Four circular cross-sectional area matrices have been studied and comparison was made between them. These include; storage with Flat Plate partitions (FP), storage with Corrugated Plate partitions (CP), storage with Wire Mesh partitions (WM), and storage Without Partitions (WP). A numerical model has been developed to simulate dynamic thermal energy transfer within (PTES) to include the important thermal effects of the partitions within porous matrices. The developed numerical model is characterized by system of differential energy conservation equations, these equations are solved numerically by time marching implicit method. The theoretical analysis and computational scheme validity has been verified through comparisons with measured data from the experimental work conducted in this work. The investigation has been done for Reynolds number, Re, of 1270 <Re < 8050. A convenient agreement was found between theoretical and experimental results for all of the tested matrices. The metal partitions were specified to have considerable effect on the thermal response for each type of the tested materials. From the comparison of different matrices concerning their ratio between pressure drop and heat transfer, it was found that the (CP) matrix has the highest performance. In this work, an improved transient method was presented for the calculation of the average heat transfer coefficient for porous flow channels along the axial direction with the thermal effects of the metal partitions. A correlation equation been developed for the J-factor have for each matrix material at the range of Reynold’s number under investigation. The new (three) correlations predicting the J-factor are found to be in reasonable agreement with the limited published data. However, these correlations have been included the effect of the inside partitions, which have been ignored in all previous published data.
Experimental Researches on Obtaining Sintered Composite Materials with Copper Matrix
Authors: Caliman R
Published: September 2020

Conventional and natural materials, limited in quantity or for which high energy consumption is required, are increasingly being replaced by composite materials, as a very good alternative to the exploitation, energy and environmental problems caused by the production of classic. The relative shape and dimensions of the reinforcing component as well as the structure delimit the composite materials reinforced with particles, the filamentary composite materials and the stratified ones. The general properties of the composite materials are decisively influenced by the nature and properties of the constituents, by the volumetric fraction of the reinforcing component and by its orientation in the composite material, as well, as by the mechanical strength of the matrix - fiber/particle interface. The pieces sintered from metallic powders have special physical and chemical characteristics, determined both by the composition and structure of the existing phases, as well as by the size, shape and distribution of the grains. This paper aims to highlight the particularities of the process of obtaining by sintering a category of composite materials with the copper matrix as well as their characterization with regard to the physical-mechanical properties acquired as a result of sintering. Thus, for the production of parts with advanced compactness, the process of double pressing and double sintering is applied. The first pressing is performed with moderate pressures (3000 daN/cm2) and the sintering, at 800°C, with a bearing of about 30 minutes. The second pressing is performed at high pressures (5000 ÷ 6000 daN/cm2) and is followed by the final sintering, under normal regime. Regarding the sintered metal composite materials, with the role of friction, the most important mechanical property is the hardness. This is a function of the bonding forces between the particles, density and degree of resistance of the material at the test site and can be determined by the Brinell method.
Experimental Researches on the Tribological Behavior of Composite Materials Sintered with Copper Matrix
Authors: Caliman R
Published: September 2020

Particulate materials (fillers) can be used within resistance structures only embedded in a support material called a matrix. Most often, in composite constructions, completely different materials can be combined in such a way that their individual properties reach optimum action. Usually, these are pairs of materials to which one has a bearing function, while the other has the purpose of contributing to taking over the moment of inertia. In this paper, a study is carried out regarding the behavior of abrasive wear of some composite materials with the copper matrix, testing the samples obtained by sintering making for different values of the applied load as well as of the relative sliding speed. Starting from the studied literature, fractions of sintered metallic composite materials were developed and having the copper matrix, which were tested in terms of physical - mechanical and tribological properties. The prepared powders were dosed according to the recipes (Cu 60 ÷ 66.4%, Fe 10%, Sn 7.4%, graphite 3.5 ÷ 25%, SiC 3 ÷ 4%, SiO2 9.7%), and the resulting mixtures have been homogenized in order to achieve homogeneous mixtures that will ensure, finally, a good reproducibility of the physical-mechanical properties for the sintered material. For forming, a cylindrical die having a surface area of 2 cm2 was used. The working pressures varied in the range 5000 ÷ 6000 daN/cm2. The densities obtained for the compressed samples were determined by weighing using the METTLER analytical balance and measured with the micrometer, for volume calculation. The density values for “raw” are in the range 4.47 ÷ 5.01 g/cm3.
Cloud manufacturing - the connection between RAMI 4.0 and IoT
Authors: Ciortea E M
Published: September 2020

The paper presents an empirical analysis regarding the advantages offered by cloud manufacturing, the need to analyze RAMI 4.0 and not least IoT applications. The latter using high performance platforms can lead to the modernization of the automation, tracking and control systems, but they also add to the optimization systems in order to increase the performance. RAMI offers a 3D analysis of the entire manufacturing flow, a system that can be more effectively analyzed, interpreted and can be intervened to grant mandatory maintenance. Cloud manufacturing offers an overview of the entire manufacturing process with all the resources and resources used, as well as an overall analysis regarding any possible interventions needed to optimize the manufacturing system. In order to be able to draw the most relevant conclusions in real time, we simulated such a system with the help offered by Petri nets. We chose the Petri nets because they are easier to interpret, they provide real-time information, modifications can be made relatively easily so that decisions can be made in the shortest time so as not to disturb the manufacturing system. Because cloud manufacturing, the manufacturing system and the IoT platforms have been presented in previous works on the same manufacturing system, in this paper I will review them and focus more on the cloud manufacturing relationship and RAMI 4.0.
“Virtual Pole” method applied at the profiling of the rotary cutter tool for processing of ball screw
Authors: Costin G A , Teodor V G , Oancea N
Published: September 2020

“Virtual pole” method represents a variant of the normals theorem, which can be used for profiling of tools that generate by enwrapping, by the rolling method. This variant of determining the enveloping condition allows to avoid the need to write, in explicit form, the relative movements between the piece and the tool, while remaining scientifically rigorous. In the paper, an application of the „virtual pole” method is presented, for the profiling of the rotary cutter tool designed to process a ball screw type piece. The specific form of the enwrapping condition was compared with a specific form obtained by a classical theorem.
Aerodynamic development of a high-pressure ratio compressor for an advanced microturbine powerplant
Authors: Dumitrescu O , Drăgan V , Gherman B
Published: September 2020

Microturbine engines are increasing in popularity both for small poly-generation power plants and unmanned aerial vehicle; however, their overall efficiency is severely limited by their thermodynamic cycle and component efficiency. This compressor allows the real cycle of the engine to operate with lower specific fuel consumption, extending the rage of the vehicle and lowering pollutant emissions. Optimization methods were implemented in the compressor design, in order to increase the aerodynamic efficiency. A 4.5:1 pressure ratio was selected in order to keep the exhaust jet subsonic. Linear models were used to optimize the speed and gross geometry while the TEIS and later fully viscous 3D models were used successively to optimize the end walls and blade shapes. For all numerical simulations, the Menter SST turbulence model was used. In order to minimize modelling errors, the rotor-stator interface was placed as far as possible downstream of the impeller.
Maintenance of recovery boilers from VLCC shipboard
Authors: Faităr C , Nedelcu A , Buzbuchi N , Stan L , Dumitrache C
Published: September 2020

The integrated maintenance and diagnosis system is intended for the measurement, monitoring, diagnosis, prediction and analysis of the main technical and functional parameters of a mechanical plant for its safe operation. Various software versions are implemented on modern ships that can ensure constant and efficient surveillance of all systems. These integrated systems of maintenance can focus on a category of aggregates and can prevent a great part of the defects that result from the incorrect exploitation of the respective aggregate or the lack of ensuring an efficient maintenance process. Integrated automatic diagnostics systems for onboard installations are the most efficient means of operation used for a wide range of applications. Also, integrated systems for automatic fault diagnosis - ISAFD is intended for measuring, monitoring and analyzing the technical parameters of machines used in the energy, chemical, metallurgical, food, construction or naval.