bluuebunny/crossref_metadata_2025 huggingface dataset:
Three-Dimensional Combined Finite-Discrete Element Modeling of Shear Fracture Process in Direct Shearing of Rough Concrete–Rock Joints
Authors: Min Gyeongjo , Fukuda Daisuke , Oh Sewook , Kim Gyeonggyu , Ko Younghun , Liu Hongyuan , Chung Moonkyung , Cho Sangho
Published: November 2020

A three-dimensional combined finite-discrete element element method (FDEM), parallelized by a general-purpose graphic-processing-unit (GPGPU), was applied to identify the fracture process of rough concrete–rock joints under direct shearing. The development process of shear resistance under the complex interaction between the rough concrete–rock joint surfaces, i.e., asperity dilatation, sliding, and degradation, was numerically simulated in terms of various asperity roughness under constant normal confinement. It was found that joint roughness significantly affects the development of overall joint shear resistance. The main mechanism for the joint shear resistance was identified as asperity sliding in the case of smoother joint roughness and asperity degradation in the case of rougher joint asperity. Moreover, it was established that the bulk internal friction angle increased with asperity angle increments in the Mohr–Coulomb criterion, and these results follow Patton’s theoretical model. Finally, the friction coefficient in FDEM appears to be an important parameter for simulating the direct shear test because the friction coefficient affects the bulk shear strength as well as the bulk internal friction angle. In addition, the friction coefficient of the rock–concrete joints contributes to the variation of the internal friction angle at the smooth joint than the rough joint.
Climate Sensitivity and Feedback of a New Coupled Model (K-ACE) to Idealized CO2 Forcing
Authors: Sun Min-Ah , Sung Hyun Min , Kim Jisun , Boo Kyung-On , Lim Yoon-Jin , Marzin Charline , Byun Young-Hwa
Published: November 2020

Climate sensitivity and feedback processes are important for understanding Earth’s system response to increased CO2 concentration in the atmosphere. Many modelling groups that contribute to Coupled Model Intercomparison Project phase 6 (CMIP6) have reported a larger equilibrium climate sensitivity (ECS) with their models compared to CMIP5 models. This consistent result is also found in the Korea Meteorological Administration Advanced Community Earth System model (K-ACE). Idealized climate simulation is conducted as an entry card for CMIP6 to understand Earth’s system response in new coupled models and compared to CMIP5 models. The ECS in the K-ACE is 4.83 K, which is higher than the range (2.1–4.7 K) of CMIP5 models in sensitivity to CO2 change and higher bound (1.8–5.6 K) of CMIP6 models. The radiative feedback consists of clear-sky and cloud radiative feedback. Clear-sky feedback of K-ACE is similar to CMIP5 models whereas cloud feedback of K-ACE is more positive. The result is attributable for strong positive shortwave cloud radiative effect (CRE) feedback associated with reduced low-level cloud cover at mid latitude in both hemispheres. Despite the cancellations in strong negative long wave CRE feedback with the changes in high-level clouds in the tropics, shortwave CRE has a dominant effect in net CRE. Detailed understanding of cloud feedback and cloud properties needs further study.
Airborne Wear Particle Emissions Produced during the Dyno Bench Tests with a Slag Containing Semi-Metallic Brake Pads
Authors: Matějka Vlastimil , Perricone Guido , Vlček Jozef , Olofsson Ulf , Wahlström Jens
Published: November 2020

The aim of the present paper is to investigate the level of airborne wear particles released during the dyno-bench tests with the brake pads consisting of alkali-activated slag as an abrasive. Airborne wear particles are generated with a full-scale dyno-bench adapted for airborne wear particles emission studies. The tested disc brake is equipped with two semi-metallic brake pads and a grey cast iron brake disc. A reduced Los Angeles City Traffic (LACT) driving cycle, developed within the LOWBRASYS project (European Union’s Horizon 2020 research and innovation programme), is used to mimic city driving. The same friction pair is used six times with reduced LACT cycle. The weight loss and thickness of the pads and disc are registered after each test cycle ends. The amount of the airborne wear particles emissions released during each test cycle are characterized using a PM10 impactor and electric low-pressure impactor. The obtained data of wear particle emissions are correlated with the parameters of the brake stops. The maximum disc temperature was indicated as the parameter having the largest influence on the production of particle emissions together with the duration of the brake event
Automated Conditional Screening of Multiple Escherichia coli Strains in Parallel Adaptive Fed-Batch Cultivations
Authors: Hans Sebastian , Haby Benjamin , Krausch Niels , Barz Tilman , Neubauer Peter , Cruz-Bournazou Mariano Nicolas
Published: November 2020

In bioprocess development, the host and the genetic construct for a new biomanufacturing process are selected in the early developmental stages. This decision, made at the screening scale with very limited information about the performance in larger reactors, has a major influence on the efficiency of the final process. To overcome this, scale-down approaches during screenings that show the real cell factory performance at industrial-like conditions are essential. We present a fully automated robotic facility with 24 parallel mini-bioreactors that is operated by a model-based adaptive input design framework for the characterization of clone libraries under scale-down conditions. The cultivation operation strategies are computed and continuously refined based on a macro-kinetic growth model that is continuously re-fitted to the available experimental data. The added value of the approach is demonstrated with 24 parallel fed-batch cultivations in a mini-bioreactor system with eight different Escherichia coli strains in triplicate. The 24 fed-batch cultivations were run under the desired conditions, generating sufficient information to define the fastest-growing strain in an environment with oscillating glucose concentrations similar to industrial-scale bioreactors.
Apple Supplementation Improves Hemodynamic Parameter and Attenuates Atherosclerosis in High-Fat Diet-Fed Apolipoprotein E-Knockout Mice
Authors: Soleti Raffaella , Trenteseaux Charlotte , Fizanne Lionel , Coué Marine , Hilairet Gregory , Kasbi-Chadli Fatima , Mallegol Patricia , Chaigneau Julien , Boursier Jerome , Krempf Michel , Orsel Mathilde , Ouguerram Khadija , Andriantsitohaina Ramaroson
Published: November 2020

Epidemiological studies describe the association between apple consumption and improved cardiovascular and metabolic dysfunction. Our recent multiparametric screening on cellular model studies has shown that apples exhibit vascular tropism including Granny Smith (GS) variety independently of the storage condition. The present study aimed to evaluate the cardiovascular and metabolic protection of supplementation of GS variety after storage in classic cold (GSCC) and extreme ultra-low oxygen conditions (GSXO) in the apolipoprotein E-deficient 8-week-old mice fed with high fat diet for 14 weeks. Supplementation with GSCC and GXO decreases circulating triglycerides, the expression of genes involved in lipogenesis, without change in cholesterol and glucose concentrations and HOMA-IR. Only GSXO supplementation ameliorates body weight gain, insulin level, and HDL/LDL ratio. GSXO supplementation does not modify cardiac parameters; while supplementation with GSCC decreases heart rate and improves cardiac output. Interestingly, GSCC and GSXO reduce systolic and diastolic blood pressure with a differential time course of action. These effects are associated with substantial decrease of atherosclerotic lesions. These data reinforce the knowledge about the vascular tropism of apple supplementation and underscore their ability to improve both cardiovascular and metabolic alterations in a mouse model of atherosclerosis.
p62-Nrf2-p62 Mitophagy Regulatory Loop as a Target for Preventive Therapy of Neurodegenerative Diseases
Authors: Gureev Artem P. , Sadovnikova Irina S. , Starkov Natalia N. , Starkov Anatoly A. , Popov Vasily N.
Published: November 2020

Turnover of the mitochondrial pool due to coordinated processes of mitochondrial biogenesis and mitophagy is an important process in maintaining mitochondrial stability. An important role in this process is played by the Nrf2/ARE signaling pathway, which is involved in the regulation of the expression of genes responsible for oxidative stress protection, regulation of mitochondrial biogenesis, and mitophagy. The p62 protein is a multifunctional cytoplasmic protein that functions as a selective mitophagy receptor for the degradation of ubiquitinated substrates. There is evidence that p62 can positively regulate Nrf2 by binding to its negative regulator, Keap1. However, there is also strong evidence that Nrf2 up-regulates p62 expression. Thereby, a regulatory loop is formed between two important signaling pathways, which may be an important target for drugs aimed at treating neurodegeneration. Constitutive activation of p62 in parallel with Nrf2 would most likely result in the activation of mTORC1-mediated signaling pathways that are associated with the development of malignant neoplasms. The purpose of this review is to describe the p62-Nrf2-p62 regulatory loop and to evaluate its role in the regulation of mitophagy under various physiological conditions.
Quantifying the Effect of Financial Burden on Health-Related Quality of Life among Patients with Non-Hodgkin’s Lymphomas
Authors: Xu Richard Huan , Wong Eliza Lai-yi , Su Yi , Zhang Hongyu , Zhang Wei , Dong Dong
Published: November 2020

Objective: This study aimed to assess the association of health-related quality of life (HRQoL) with financial burden among patients with non-Hodgkin’s lymphoma (NHL) in China. Methods: The data used for the analyses came from a nationwide survey to investigate the health status of patients with lymphomas in China. The EQ-5D and EORTC QLQ-C30 were used to assess the patients’ HRQoL. The financial burden was calculated using both subjective and objective methods. The chi-squared test, Kruskal–Wallis one-way analysis of variance, ordinal least squared model, and Tobit regression model were used to estimate the relationship between financial burden and HRQoL. Results: Data from 1549 patients who reported living with 11 subtypes of NHL were elicited for our analysis. Approximately 60% of respondents reported suffering moderate to high financial burdens. A significant relationship between increased financial burden and reduced HRQoL scores, including the EQ-Index, physical, emotional, and social functioning, was identified. Compared with using an objective method to measure financial burden, patients with NHL indicated a poorer HRQoL when using a subjective method to measure financial burden. Conclusion: Medical professionals should select highly cost-effective treatments and ensure that patients understand the potential financial consequences of those treatments.
Trop2: Jack of All Trades, Master of None
Authors: Lenárt Sára , Lenárt Peter , Šmarda Jan , Remšík Ján , Souček Karel , Beneš Petr
Published: November 2020

Trophoblast cell surface antigen 2 (Trop2) is a widely expressed glycoprotein and an epithelial cell adhesion molecule (EpCAM) family member. Although initially identified as a transmembrane protein, other subcellular localizations and processed forms were described. Its congenital mutations cause a gelatinous drop-like corneal dystrophy, a disease characterized by loss of barrier function in corneal epithelial cells. Trop2 is considered a stem cell marker and its expression associates with regenerative capacity in various tissues. Trop2 overexpression was described in tumors of different origins; however, functional studies revealed both oncogenic and tumor suppressor roles. Nevertheless, therapeutic potential of Trop2 was recognized and clinical studies with drug–antibody conjugates have been initiated in various cancer types. One of these agents, sacituzumab govitecan, has been recently granted an accelerated approval for therapy of metastatic triple-negative breast cancer. In this article, we review the current knowledge about the yet controversial function of Trop2 in homeostasis and pathology.
Current Advances and Hurdles in Chimeric Antigen Receptor Technology
Authors: McComb Scott , Lee Seung-Hwan
Published: November 2020

Since tumor-specific T cells were first utilized to treat melanoma patients in 1986 [...]
Modulation of de Novo Lipogenesis Improves Response to Enzalutamide Treatment in Prostate Cancer
Authors: Lounis Mohamed Amine , Péant Benjamin , Leclerc-Desaulniers Kim , Ganguli Dwaipayan , Daneault Caroline , Ruiz Matthieu , Zoubeidi Amina , Mes-Masson Anne-Marie , Saad Fred
Published: November 2020

De novo lipogenesis (DNL) is now considered as a hallmark of cancer. The overexpression of key enzymes of DNL is characteristic of both primary and advanced disease and may play an important role in resistance to therapies. Here, we showed that DNL is highly enhanced in castrate resistant prostate cancer (CRPC) cells compared to hormone sensitive and enzalutamide resistant cells. This observation suggests that this pathway plays an important role in the initiation of aggressive prostate cancer and in the development of enzalutamide resistance. Importantly, here we show that both prostate cancer cells sensitive and resistant to enzalutamide are dependent on DNL to proliferate. We next combined enzalutamide with an inhibitor of Stearoyl CoA Desaturase 1 (SCD1), an important enzyme in DNL, and observed significantly reduced tumor growth caused by the important change in tumoral lipid desaturation. Our findings suggest that the equilibrium between monounsaturated fatty acids and saturated fatty acids is essential in the establishment of the more aggressive prostate cancer phenotype and that the combination therapy induces a disruption of this equilibrium leading to an important decrease of cell proliferation. These findings provide new insights into the role of DNL in the progression of prostate cancer cells. The study also provides the rationale for the use of an inhibitor of SCD1 in combination with enzalutamide to improve response, delay enzalutamide resistance and improve disease free progression.
Asymmetric Synthesis of Optically Pure Aliphatic Amines with an Engineered Robust ω-Transaminase
Authors: Dong Linhan , Meng Qinglong , Ramírez-Palacios Carlos , Wijma Hein J. , Marrink Siewert J. , Janssen Dick B.
Published: November 2020

The production of chiral amines by transaminase-catalyzed amination of ketones is an important application of biocatalysis in synthetic chemistry. It requires transaminases that show high enantioselectivity in asymmetric conversion of the ketone precursors. A robust derivative of ω-transaminase from Pseudomonasjessenii (PjTA-R6) that naturally acts on aliphatic substrates was constructed previously by our group. Here, we explore the catalytic potential of this thermostable enzyme for the synthesis of optically pure aliphatic amines and compare it to the well-studied transaminases from Vibrio fluvialis (VfTA) and Chromobacterium violaceum (CvTA). The product yields indicated improved performance of PjTA-R6 over the other transaminases, and in most cases, the optical purity of the produced amine was above 99% enantiomeric excess (e.e.). Structural analysis revealed that the substrate binding poses were influenced and restricted by the switching arginine and that this accounted for differences in substrate specificities. Rosetta docking calculations with external aldimine structures showed a correlation between docking scores and synthetic yields. The results show that PjTA-R6 is a promising biocatalyst for the asymmetric synthesis of aliphatic amines with a product spectrum that can be explained by its structural features.
Simultaneous Induction of Glycolysis and Oxidative Phosphorylation during Activation of Hepatic Stellate Cells Reveals Novel Mitochondrial Targets to Treat Liver Fibrosis
Authors: Smith-Cortinez Natalia , van Eunen Karen , Heegsma Janette , Serna-Salas Sandra Alejandra , Sydor Svenja , Bechmann Lars P. , Moshage Han , Bakker Barbara M. , Faber Klaas Nico
Published: November 2020

Upon liver injury, hepatic stellate cells (HSCs) transdifferentiate to migratory, proliferative and extracellular matrix-producing myofibroblasts (e.g., activated HSCs; aHSCs) causing liver fibrosis. HSC activation is associated with increased glycolysis and glutaminolysis. Here, we compared the contribution of glycolysis, glutaminolysis and mitochondrial oxidative phosphorylation (OXPHOS) in rat and human HSC activation. Basal levels of glycolysis (extracellular acidification rate ~3-fold higher) and particularly mitochondrial respiration (oxygen consumption rate ~5-fold higher) were significantly increased in rat aHSCs, when compared to quiescent rat HSC. This was accompanied by extensive mitochondrial fusion in rat and human aHSCs, which occurred without increasing mitochondrial DNA content and electron transport chain (ETC) components. Inhibition of glycolysis (by 2-deoxy-D-glucose) and glutaminolysis (by CB-839) did not inhibit rat aHSC proliferation, but did reduce Acta2 (encoding α-SMA) expression slightly. In contrast, inhibiting mitochondrial OXPHOS (by rotenone) significantly suppressed rat aHSC proliferation, as well as Col1a1 and Acta2 expression. Other than that observed for rat aHSCs, human aHSC proliferation and expression of fibrosis markers were significantly suppressed by inhibiting either glycolysis, glutaminolysis or mitochondrial OXPHOS (by metformin). Activation of HSCs is marked by simultaneous induction of glycolysis and mitochondrial metabolism, extending the possibilities to suppress hepatic fibrogenesis by interfering with HSC metabolism.
Plasma-Activated Polyvinyl Alcohol Foils for Cell Growth
Authors: Slepičková Kasálková Nikola , Slepička Petr , Ivanovská Barbora , Trávníčková Martina , Malinský Petr , Macková Anna , Bačáková Lucie , Švorčík Václav
Published: November 2020

Hydrogels, and not only natural polysaccharide hydrogels, are substances capable of absorbing large amounts of water and physiological fluids. In this study, we set out to optimize the process for preparing polyvinyl alcohol (PVA) hydrogels. Subsequently, we doped PVA foils with cellulose powder, with poly(ethylene glycol) (PEG) or with gold nanoparticles in PEG colloid solutions (Au). The foils were then modified in a plasma discharge to improve their biocompatibility. The properties of PVA foils were studied by various analytical methods. The use of a suitable dopant can significantly affect the surface wettability, the roughness, the morphology and the mechanical properties of the material. Plasma treatment of PVA leads to ultraviolet light-induced crosslinking and decreasing water absorption. At the same time, this treatment significantly improves the cytocompatibility of the polymer, which is manifested by enhanced growth of human adipose-derived stem cells. This positive effect on the cell behavior was most pronounced on PVA foils doped with PEG or with Au. This modification of PVA therefore seems to be most suitable for the use of this polymer as a cell carrier for tissue engineering, wound healing and other regenerative applications.
Structure and Tribological Properties of AlCrN + CrCN Coating
Authors: Lukaszkowicz Krzysztof , Sondor Jozef , Paradecka Agnieszka , Pawlyta Mirosława , Chmiela Bartosz , Pancielejko Mieczysław , Szczucka-Lasota Bożena , Węgrzyn Tomasz , Tański Tomasz
Published: November 2020

The paper presents results of the investigation of the AlCrN and AlCrN + CrCN coatings, deposited by arc evaporation method on the austenitic steel substrate. Topography studies performed with the use of AFM showed that the roughness value was 24 nm for AlCrN and 14 nm for CrCN. Chemical analysis carried out with energy dispersive X-rays spectroscopy confirmed the chemical composition of the coatings. Transmission electron microscopy (TEM) investigations showed a column structure of AlCrN and CrCN layers with a width in the range of 10–200 nm. Tribological properties analyzed using a scratch test and ball-on-disc method showed a good adhesion of the coatings to the substrate (LC2 is 40 and 46 N for AlCrN and AlCrN + CrCN, respectively) and its high wear resistance; the use of an additional CrCN layers caused a decrease in the friction coefficient by 19%. Structure modification of the AlCrN + CrCN coating system and the related improvement in its mechanical and tribological properties allowed increasing the lifetime of the coated elements. The original approach was to produce a dual-layer coating, consisting of an internal, hard AlCrN layer and an external layer of CrCN, providing good tribological properties, as well as an appropriate forming of the transition zone between the layers.
Synthesis, Structure, and Dielectric Properties of (3-Nitroanilinium) (18-Crown) (PF6)
Authors: Wang Le , Qin Liu-lei , Liu Yang , Wang Peng , Xu Hui-ting , Liu Zun-qi
Published: November 2020

(3-Nitroanilinium) (18-crown) (PF6) (1), which is an organic-inorganic hybrid containing one-dimensional chains of hydrogen-bonded supramolecular cations, was synthesized under slow evaporation conditions and subjected to differential scanning calorimetry, temperature-dependent dielectric measurements, and variable-temperature single-crystal X-ray diffraction analysis. These analyses revealed the occurrence of a reversible structural phase transition [P21/n P21/c] at 223 K and a dielectric anomaly, which, based on the results of structural analysis and potential energy calculations, was attributed to the synergistic effect between the pendulum-like motion of the nitro group in the supramolecular cation, (3-nitroanilinium)(18-crown), and the order-disorder motion of PF6− anions.
Sea Slugs—“Rare in Space and Time”—But Not Always
Authors: Schubert Julie , Smith Stephen D. A.
Published: November 2020

The term “rare in space and time” is often used to typify the spatial and temporal patterns of occurrence of heterobranch sea slugs. However, “rare” in this context has not been clearly defined. In an attempt to provide more insight into the concept of rarity in sea slug assemblages, we analysed abundance data from 209 individual surveys conducted over a 5-year period in a subtropical estuary and a 7-year period on a shallow coastal reef, on the Sunshine Coast, Qld, Australia. Using an ‘intuitive’ method (<10 individuals recorded over the study), and the ‘quartile’ method we assessed numerical rarity (number of individuals of a species seen over the study period) and temporal rarity (frequency of observation). We also assessed numerical rarity using octaves based on log2 abundance bins. The quartile method did not effectively capture either measure of rarity. The octave method, however, fitted closely to subjective classifications of abundance and defined a similar number of species as rare when compared to the intuitive method. Using the octave method, 66% of species in both the estuary and on the reef, were considered as rare. Consequently, we recommend the octave method to allocate abundance classifications. To address the poor fit for temporal classifications based on quartiles, we propose the following as a working model for wider testing: rare ≤25% of surveys; uncommon 26−50%, common 51−75%; and abundant >75%.
Evolutionary History of the Galápagos Rail Revealed by Ancient Mitogenomes and Modern Samples
Authors: Chaves Jaime A. , Martinez-Torres Pedro J. , Depino Emiliano A. , Espinoza-Ulloa Sebastian , García-Loor Jefferson , Beichman Annabel C. , Stervander Martin
Published: November 2020

The biotas of the Galápagos Islands are one of the best studied island systems and have provided a broad model for insular species’ origins and evolution. Nevertheless, some locally endemic taxa, such as the Galápagos Rail Laterallus spilonota, remain poorly characterized. Owing to its elusive behavior, cryptic plumage, and restricted distribution, the Galápagos Rail is one of the least studied endemic vertebrates of the Galapagos Islands. To date, there is no genetic data for this species, leaving its origins, relationships to other taxa, and levels of genetic diversity uncharacterized. This lack of information is critical given the adverse fate of island rail species around the world in the recent past. Here, we examine the genetics of Galápagos Rails using a combination of mitogenome de novo assembly with multilocus nuclear and mitochondrial sequencing from both modern and historical samples. We show that the Galápagos Rail is part of the “American black rail clade”, sister to the Black Rail L. jamaicensis, with a colonization of Galápagos dated to 1.2 million years ago. A separate analysis of one nuclear and two mitochondrial markers in the larger population samples demonstrates a shallow population structure across the islands, possibly due to elevated island connectivity. Additionally, birds from the island Pinta possessed the lowest levels of genetic diversity, possibly reflecting past population bottlenecks associated with overgrazing of their habitat by invasive goats. The modern and historical data presented here highlight the low genetic diversity in this endemic rail species and provide useful information to guide conservation efforts.
An Anti-Nucleocapsid Antigen Sars-Cov-2 Total Antibody Assay Finds Comparable Results in Edta-Anticoagulated Whole Blood Obtained from Capillary and Venous Blood Sampling
Authors: Risch Martin , Kovac Marc , Risch Corina , Hillmann Dorothea , Ritzler Michael , Wohlwend Nadia , Lung Thomas , Allmann Michael , Seger Christoph , Risch Lorenz
Published: November 2020

Although SARS-CoV-2 antibody assays have been found to provide valid results in EDTA-anticoagulated whole blood, so far, they have not demonstrated that antibody levels in whole blood originating from capillary blood samples are comparable to antibody levels measured in blood from a venous origin. Here, blood is drawn simultaneously by capillary and venous blood sampling. Antibody titers are determined by an assay employing electrochemiluminescence (ECLIA) and SARS-CoV-2 total immunoglobulins are detected with specificity directed against the nucleocapsid antigen. Six individuals with confirmed COVID-19 and six individuals without COVID-19 are analyzed. Antibody titers in capillary venous whole blood did not show significant differences, and when corrected for hematocrit, they did not differ from the results obtained from serum. In conclusion, capillary sampled EDTA-anticoagulated whole blood seems to be an attractive alternative matrix for the evaluation of SARS-CoV-2 antibodies when employing ECLIA for detecting total antibodies directed against nucleocapsid antibodies.
A Digital Image Confidentiality Scheme Based on Pseudo-Quantum Chaos and Lucas Sequence
Authors: Butt Khushbu Khalid , Li Guohui , Masood Fawad , Khan Sajid
Published: November 2020

Several secure image encryption systems have been researched and formed by chaotic mechanisms in current decades. This work recommends an innovative quantum color image encryption method focused on the Lucas series-based substitution box to enhance the competence of encryption. The suggested encryption technique has more excellent key space and significant confidentiality. The chaotic system, along with the substitution box, exhibits additional complicated dynamical behavior, sufficient arbitrariness, and uncertainty than all others focused on just chaotic models. Theoretical and simulation assessments show that the offered image encryption performs admirably, its traditional equivalents in terms by efficiency in terms of statistical analysis.
Beta Type Stirling Engine. Schmidt and Finite Physical Dimensions Thermodynamics Methods Faced to Experiments
Authors: Dobre Cătălina , Grosu Lavinia , Costea Monica , Constantin Mihaela
Published: November 2020

The paper presents experimental tests and theoretical studies of a Stirling engine cycle applied to a β-type machine. The finite physical dimension thermodynamics (FPDT) method and 0D modeling by the imperfectly regenerated Schmidt model are used to develop analytical models for the Stirling engine cycle. The purpose of this study is to show that two simple models that take into account only the irreversibility due to temperature difference in the heat exchangers and imperfect regeneration are able to indicate engine behavior. The share of energy loss for each is determined using these two models as well as the experimental results of a particular engine. The energies exchanged by the working gas are expressed according to the practical parameters, which are necessary for the engineer during the entire project, namely the maximum pressure, the maximum volume, the compression ratio, the temperature of the heat sources, etc. The numerical model allows for evaluation of the energy processes according to the angle of the crankshaft (kinematic–thermodynamic coupling). The theoretical results are compared with the experimental research. The effect of the engine rotation speed on the power and efficiency of the actual operating machine is highlighted. The two methods show a similar variation in performance, although heat loss due to imperfect regeneration is evaluated differently.
Diauxic Growth at the Mesoscopic Scale
Authors: Lachowicz Mirosław , Dȩbowski Mateusz
Published: November 2020

In the present paper, we study a diauxic growth that can be generated by a class of model at the mesoscopic scale. Although the diauxic growth can be related to the macroscopic scale, similarly to the logistic scale, one may ask whether models on mesoscopic or microscopic scales may lead to such a behavior. The present paper is the first step towards the developing of the mesoscopic models that lead to a diauxic growth at the macroscopic scale. We propose various nonlinear mesoscopic models conservative or not that lead directly to some diauxic growths.
Linear and Fisher Separability of Random Points in the d-Dimensional Spherical Layer and Inside the d-Dimensional Cube
Authors: Sidorov Sergey , Zolotykh Nikolai
Published: November 2020

Stochastic separation theorems play important roles in high-dimensional data analysis and machine learning. It turns out that in high dimensional space, any point of a random set of points can be separated from other points by a hyperplane with high probability, even if the number of points is exponential in terms of dimensions. This and similar facts can be used for constructing correctors for artificial intelligent systems, for determining the intrinsic dimensionality of data and for explaining various natural intelligence phenomena. In this paper, we refine the estimations for the number of points and for the probability in stochastic separation theorems, thereby strengthening some results obtained earlier. We propose the boundaries for linear and Fisher separability, when the points are drawn randomly, independently and uniformly from a d-dimensional spherical layer and from the cube. These results allow us to better outline the applicability limits of the stochastic separation theorems in applications.
Bell-Type Correlation at Quantum Phase Transitions in Spin-1 Chain
Authors: Lee Dongkeun , Son Wonmin
Published: November 2020

For the identification of non-trivial quantum phase, we exploit a Bell-type correlation that is applied to the one-dimensional spin-1 XXZ chain. It is found that our generalization of bipartite Bell correlation can take a decomposed form of transverse spin correlation together with high-order terms. The formulation of the density-matrix renormalisation group is utilized to obtain the ground state of a given Hamiltonian with non-trivial phase. Subsequently Bell-type correlation is evaluated through the analysis of the matrix product state. Diverse classes of quantum phase transitions in the spin-1 model are identified precisely through the evaluation of the first and the second moments of the generalized Bell correlations. The role of high-order terms in the criticality has been identified and their physical implications for the quantum phase have been revealed.
Efficient Markets and Contingent Claims Valuation: An Information Theoretic Approach
Authors: Lindgren Jussi
Published: November 2020

This research article shows how the pricing of derivative securities can be seen from the context of stochastic optimal control theory and information theory. The financial market is seen as an information processing system, which optimizes an information functional. An optimization problem is constructed, for which the linearized Hamilton–Jacobi–Bellman equation is the Black–Scholes pricing equation for financial derivatives. The model suggests that one can define a reasonable Hamiltonian for the financial market, which results in an optimal transport equation for the market drift. It is shown that in such a framework, which supports Black–Scholes pricing, the market drift obeys a backwards Burgers equation and that the market reaches a thermodynamical equilibrium, which minimizes the free energy and maximizes entropy.
Generative Art with Swarm Landscapes
Authors: de Andrade Diogo , Fachada Nuno , Fernandes Carlos M. , Rosa Agostinho C.
Published: November 2020

We present a generative swarm art project that creates 3D animations by running a Particle Swarm Optimization algorithm over synthetic landscapes produced by an objective function. Different kinds of functions are explored, including mathematical expressions, Perlin noise-based terrain, and several image-based procedures. A method for displaying the particle swarm exploring the search space in aesthetically pleasing ways is described. Several experiments are detailed and analyzed and a number of interesting visual artifacts are highlighted.
Video Summarization Based on Mutual Information and Entropy Sliding Window Method
Authors: Li WenLin , Qi DeYu , Zhang ChangJian , Guo Jing , Yao JiaJun
Published: November 2020

This paper proposes a video summarization algorithm called the Mutual Information and Entropy based adaptive Sliding Window (MIESW) method, which is specifically for the static summary of gesture videos. Considering that gesture videos usually have uncertain transition postures and unclear movement boundaries or inexplicable frames, we propose a three-step method where the first step involves browsing a video, the second step applies the MIESW method to select candidate key frames, and the third step removes most redundant key frames. In detail, the first step is to convert the video into a sequence of frames and adjust the size of the frames. In the second step, a key frame extraction algorithm named MIESW is executed. The inter-frame mutual information value is used as a metric to adaptively adjust the size of the sliding window to group similar content of the video. Then, based on the entropy value of the frame and the average mutual information value of the frame group, the threshold method is applied to optimize the grouping, and the key frames are extracted. In the third step, speeded up robust features (SURF) analysis is performed to eliminate redundant frames in these candidate key frames. The calculation of Precision, Recall, and Fmeasure are optimized from the perspective of practicality and feasibility. Experiments demonstrate that key frames extracted using our method provide high-quality video summaries and basically cover the main content of the gesture video.
Comparative Analysis of Energy and Exergy Performance of Hydrogen Production Methods
Authors: Martínez-Rodríguez Angel , Abánades Alberto
Published: November 2020

The study of the viability of hydrogen production as a sustainable energy source is a current challenge, to satisfy the great world energy demand. There are several techniques to produce hydrogen, either mature or under development. The election of the hydrogen production method will have a high impact on practical sustainability of the hydrogen economy. An important profile for the viability of a process is the calculation of energy and exergy efficiencies, as well as their overall integration into the circular economy. To carry out theoretical energy and exergy analyses we have estimated proposed hydrogen production using different software (DWSIM and MATLAB) and reference conditions. The analysis consolidates methane reforming or auto-thermal reforming as the viable technologies at the present state of the art, with reasonable energy and exergy efficiencies, but pending on the impact of environmental constraints as CO2 emission countermeasures. However, natural gas or electrolysis show very promising results, and should be advanced in their technological and maturity scaling. Electrolysis shows a very good exergy efficiency due to the fact that electricity itself is a high exergy source. Pyrolysis exergy loses are mostly in the form of solid carbon material, which has a very high integration potential into the hydrogen economy.
PRATD: A Phased Remote Access Trojan Detection Method with Double-Sided Features
Authors: Guo Chun , Song Zihua , Ping Yuan , Shen Guowei , Cui Yuhei , Jiang Chaohui
Published: November 2020

Remote Access Trojan (RAT) is one of the most terrible security threats that organizations face today. At present, two major RAT detection methods are host-based and network-based detection methods. To complement one another’s strengths, this article proposes a phased RATs detection method by combining double-side features (PRATD). In PRATD, both host-side and network-side features are combined to build detection models, which is conducive to distinguishing the RATs from benign programs because that the RATs not only generate traffic on the network but also leave traces on the host at run time. Besides, PRATD trains two different detection models for the two runtime states of RATs for improving the True Positive Rate (TPR). The experiments on the network and host records collected from five kinds of benign programs and 20 famous RATs show that PRATD can effectively detect RATs, it can achieve a TPR as high as 93.609% with a False Positive Rate (FPR) as low as 0.407% for the known RATs, a TPR 81.928% and FPR 0.185% for the unknown RATs, which suggests it is a competitive candidate for RAT detection.
Adaptive Doppler Compensation for Mitigating Range Dependence in Forward-Looking Airborne Radar
Authors: Khan Muhammad Bilal , Hussain Ahmed , Anjum Umar , Babar Ali Channa , Yang Xiaodong
Published: November 2020

In this paper, we present ground moving target indication (GMTI) signal processing algorithm encompassing clutter suppression, target detection and parameter estimation. One of the most significant yet least publicized is the need of the GMTI mode for a forward-looking airborne radar. The integration of GMTI mode in a forward-looking airborne radar allows reconnaissance and surveillance operations in all weather conditions. In this context, space time adaptive processing (STAP) offers a unique prospect of enabling the GMTI mode in forward looking airborne radar. STAP is a two-dimensional filter designed to suppress platform motion-induced clutter Doppler spread. Interference is characterized by a covariance matrix. In the case of a forward-looking airborne radar, the clutter Doppler is dependent on range. Clutter Doppler dependency on the range renders the training cells heterogeneous. The heterogeneity effects are particularly prominent in the near range bins. Non-homogeneous training cells have a deleterious effect on STAP performance. In this study, we propose an adaptive Doppler compensation to mitigate the degraded STAP performance in the near range bins. The adaptivity feature circumvents the need for the availability of radar parameters in real-time. The real time implementation of STAP is impeded by requirements of a large number of training samples and covariance matrix inversion. Therefore, there is a dire need to devise a framework to detect and estimate target parameters within the STAP. In this regard, we propose an efficient STAP algorithm to detect and estimate target parameters. STAP weights are applied to the input data to obtain a 3D array. The range projection of the 3D array is utilized to detect and estimate the range of the target, while the angle–Doppler projection is used to estimate spatial and temporal parameters of the target. Most of the literature on STAP is geared towards a known covariance matrix. The assumption of a known covariance matrix may degrade STAP performance because of the inherent mismatches between the actual and assumed target steering vectors. In this study, we estimate the covariance matrix based on the synthetic data generated from a model of an airborne phased array radar. The developed STAP algorithms closely mimic a real-time implementation scheme in an airborne radar platform. The results of the proposed algorithm are validated through target parameter estimation and STAP metrics on synthetic data.
Reducing the Overhead of BCH Codes: New Double Error Correction Codes
Authors: Saiz-Adalid Luis-J. , Gracia-Morán Joaquín , Gil-Tomás Daniel , Baraza-Calvo J.-Carlos , Gil-Vicente Pedro-J.
Published: November 2020

The Bose-Chaudhuri-Hocquenghem (BCH) codes are a well-known class of powerful error correction cyclic codes. BCH codes can correct multiple errors with minimal redundancy. Primitive BCH codes only exist for some word lengths, which do not frequently match those employed in digital systems. This paper focuses on double error correction (DEC) codes for word lengths that are in powers of two (8, 16, 32, and 64), which are commonly used in memories. We also focus on hardware implementations of the encoder and decoder circuits for very fast operations. This work proposes new low redundancy and reduced overhead (LRRO) DEC codes, with the same redundancy as the equivalent BCH DEC codes, but whose encoder, and decoder circuits present a lower overhead (in terms of propagation delay, silicon area usage and power consumption). We used a methodology to search parity check matrices, based on error patterns, in order to design the new codes. We implemented and synthesized them, and compared their results with those obtained for the BCH codes. Our implementation of the decoder circuits achieved reductions between 2.8% and 8.7% in the propagation delay, between 1.3% and 3.0% in the silicon area, and between 15.7% and 26.9% in the power consumption. Therefore, we propose LRRO codes as an alternative for protecting information against multiple errors.
On the Mediation Price War of 5G Providers
Authors: Toka Laszlo , Recse Akos , Cserep Mate , Szabo Robert
Published: November 2020

Virtualization guarantees that, moving toward 5G, online services will be versatile and the creation of those will be quick, satisfying the interest of end-clients to a higher degree than what is plausible today. Telcos, cloud administrators, and online application suppliers will unite for conveying those services to clients around the world. Thus, in order to help their portability, or the simple geographic range of the offered application, the business arrangements among the actors must scale over numerous domains and a guaranteed nature of joint effort among different stakeholders is important. Therefore, the vision of the 5G environment is majorly established on the federation of these partners in which they can consistently strive towards the objective of making reliable resource slices and deploying applications within for a maximal geographic reach of clients. In this environment, business perspectives will significantly impact the technical capacity of the system: the business arrangements of the providers will innately decide the accessibility and the end-client costs of certain services. In this work, we model the business relations of infrastructure providers as a variation of network formation games. We infer conditions under which the current transit-peering structure of network providers stays unblemished, and we also draw the specifics of an envisioned setup in which providers create business links among each other starting with a clean slate.
Passive Regulation of the Water Content at the Anode Chamber under Dead-Ended Conditions: Innovative Design of an Air-Breathing Proton Exchange Membrane Fuel Cell
Authors: Pérez-Guizado Pedro A. , Fernández-Sotillo Alba María , Ferreira-Aparicio Paloma
Published: November 2020

A passive regulation system for the water content has been developed and evaluated for a proton exchange membrane fuel cell. It is of particular relevance for micro-fuel cells, whose volume, weight and extra-consumption of fuel and power for subsidiary components must be kept to a minimum. This solution consists of a self-regulating humidity system implemented at the anode chamber that allows free water exchange with the environment through the surface of a gas-tight membrane. The micro-fuel cell, which is designed according to the patent WO2015025070A1, has been assembled and operated under completely passive conditions. The behavior of the anode humidity regulation system has been analyzed externally and in situ. The external part of the anode, where the humidity exchange with the environment takes place, has been isolated in a closed chamber and a hygrometer has been used to register the relative humidity in the zone near to the water exchange film. The results obtained from the operation of this innovative system are discussed in the light of the water permeation behavior of different Nafion membranes.
A Two-Step Energy Management Method Guided by Day-Ahead Quantile Solar Forecasts: Cross-Impacts on Four Services for Smart-Buildings
Authors: Calderon-Obaldia Fausto , Badosa Jordi , Migan-Dubois Anne , Bourdin Vincent
Published: November 2020

The research work hereby presented, emerges from the urge to answer the well-known question of how the uncertainty of intermittent renewable sources affects the performance of a microgrid and how could we deal with it. More specifically, we want to evaluate what could be the impact in performance of a microgrid that is intended to serve a smart-building (powered by photovoltaic panels and with battery energy storage), when the uncertainty of the photovoltaic-production forecasts is considered in the energy management process through the use of quantile forecasts. For this, several objectives (or services) are targeted based in a two-step (double-objective) energy management framework, which combines optimization-based and rule-based algorithms. The performance is evaluated based on some particular services, namely: energy cost, carbon footprint, grid peak power, and grid commitment; with the latter being a novel service proposed in the domain of microgrids. Simulations are performed whlie using data of a study-case microgrid (Drahi-Xnovation center, Ecole Polytechnique, France). The use of quantile forecasts (obtained with an analog-ensemble method) is tested as a mean to deal with (i.e., decrease) the uncertainty of the solar PV production. The proposed energy management framework is compared with basic reference strategies and the results show the superior performance of the former in almost all of the proposed services and forecasting scenarios. The fact of how optimizing for some services during the scheduling (i.e., grid commitment) can be highly detrimental for the performance of the non-targeted services, is an interesting finding of this work. The differences regarding the optimal forecasting eccentricity (i.e., the forecasting quantile) required when optimizing for the different services and seasons of the year is also considered an important conclusion of the study. This fact highlights the usefulness of the quantile forecasting approach in an energy management system, as a tool to deal with the intrinsic uncertainty of PV power production.