bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Design of a Floating Offshore Wind Turbine Large Scale Model for Control Purposes
Authors: Taruffi Federico , Di Carlo Simone , Muggiasca Sara , Fontanella Alessandro
Published: April 2021

This paper deals with the numerical design of a floating offshore wind turbine outdoor large-scale prototype based on the DTU 10MW. The objective of this work is to develop a numerical simulation environment for the design of an outdoor scaled prototype. The numerical model is realized coupling the preliminary designed Blue Growth Farm large-scale turbine model with a traditional floater, the OC3 spar buoy. The numerical model is used to evaluate the loads associated with the wind turbine when combined to a floating foundation, with the focus on the coupling between the dynamics of the control system and the one of the floating platform. In addition to this, also the consistency of loads on crucial turbine components is an interesting test bench for the evaluation of the dynamical effects and drives the final design of the physical model.
Evaluation of Deep-Water Floating Wind Turbine to Power an Isolated Water Injection System
Authors: Khan Khalid S. , dos Santos Isabelle V. M. , dos Santos Guilherme B. , Salles Maurício B. C. , Monaro Renato M.
Published: April 2021

The main objective of this paper is to evaluate the use of floating wind turbines for isolated offshore systems. The energy analysis is a vital step at the initial phase of the project to define topologies that will be able to feed subsea systems, a water injection system is considered as a example. The first location that we decided to look in detail is one of the largest oil regions discovered in the last hundred years and it is located on the Brazilian coast. It is important to highlight that the development is on the technological frontier of a new type of floating wind turbine application for deep waters. The focus of the study is to validate the perks of this application, such as, the production of clean and green energy capable enough to satisfy the load requirements of a Water Injection Systems (WIS) for Oil and Gas (O&G) production, chosen among other possibilities of subsea systems as an example. Water injection is effective to improve the oil recovery in reservoirs, but conventionally involves high energy consumption, significant emissions and expensive infrastructure. This work investigates different configurations combining a wind turbine, diesel generator and batteries to supply power to the off-grid load, with the basic premise that WIS can follow the generation available from the wind turbine, since it does not require a fixed injection rate. In the energetic point of view, the main result shows that the use of wind turbine and li-ion battery can cut emissions by half and increase the energy efficiency of the system.
Investigation of Nonlinear Difference-Frequency Wave Excitation on a Semisubmersible Offshore-Wind Platform With Bichromatic-Wave CFD Simulations
Authors: Wang Lu , Robertson Amy , Jonkman Jason , Yu Yi-Hsiang , Koop Arjen , Borràs Nadal Adrià , Li Haoran , Shi Wei , Pinguet Romain , Zhou Yang , Xiao Qing , Kumar Rupesh , Sarlak Hamid
Published: April 2021

The natural surge and pitch frequencies of semisubmersible offshore wind platforms are typically designed to be below the wave frequencies to avoid direct excitation. However, surge or pitch resonance can be excited by the nonlinear low-frequency loads generated by irregular incident waves. Second-order potential-flow models with added Morison drag have been found to underpredict this low-frequency excitation and response. As part of the OC6 project1, the authors performed computational fluid dynamics (CFD) simulations to enable a better understanding of the low-frequency loads and the limitations of lower-fidelity models. The focus of this paper is to set up a computationally cost-effective CFD simulation of a fixed semisubmersible platform to investigate nonlinear difference-frequency loads and establish the corresponding uncertainty in the results. Because of the high computing cost, CFD simulations of irregular waves can be challenging. Instead, simulations were performed with bichromatic waves having a shorter repeat period. A preliminary comparison with quadratic transfer functions from second-order potential-flow theory shows that CFD models consistently predict higher nonlinear wave loads at the difference frequency, likely because of flow separation and viscous drag not accounted for in potential-flow theory.
Mooring Fatigue Verification of the WindCrete for a 15 MW Wind Turbine
Authors: Trubat Pau , Molins Climent , Alarcon Daniel , Arramounet Valentin , Mahfouz Mohammad Youssef
Published: April 2021

LCOE reduction in FOWTs is heading to larger wind turbines in order to increase power production and capacity. NREL and DTU have recently developed a 15MW reference wind turbine, which can be used to validate the platform concepts for the next generation of wind turbines. Increasing the power of wind turbines leads to larger platforms due to the need to withstand the increase of the weight of the Nacelle Rotor Assembly, as well as the increase of the wind forces and pitching moment. Moreover, the larger the turbines and platforms the larger surge/sway and yaw unbalanced forces, which will need to be hold up by the mooring system.

The mooring system has to be designed to balance the wind and wave forces and provide the stiffness needed to the FOWT for a proper behavior. Moreover, the mooring system has to achieve enough reliability to prevent line failure that could lead to a chain reaction within a floating wind farm, and thus huge loses. Then, a complete and detailed fatigue analysis should be performed in order to guarantee the performance of the FOWT during its service life.

Within the CoReWind EU-2020 project, the Windcrete platform is upscaled to withstand the new EIA 15MW reference wind turbine. As concrete is used as a main material, the mass and inertia are larger than steel counterpart which leads to stiffer and more loaded mooring system. In this paper, the fatigue analysis of the Windcrete mooring system is assessed and compared using different methods.
Verification Study of CFD Simulation of Semi-Submersible Floating Offshore Wind Turbine Under Regular Waves
Authors: Wang Yu , Chen Hamn-Ching , Vaz Guilherme , Mewes Simon
Published: April 2021

Utilization of Computational Fluid Dynamics (CFD) codes to perform hydrodynamic analysis of Floating Offshore Wind Turbines (FOWTs) is increasing recently. However, verification studies of the simulations that quantifying numerical uncertainties and permitting a detailed validation in a next phase is often disregarded. In this work, a verification study of CFD simulations of a semi-submersible FOWT design under regular waves is performed. To accomplish this goal, Response Amplitude Operators (RAOs) are derived from the computational results of the heave, surge and pitch motions. Four grids with different grid sizes with a constant refinement ratio are generated for verification of spatial convergence. Three different time increments are paired with each grid for verification of temporal convergence. The verification study is performed by estimation of the numerical errors and uncertainties using procedures proposed by Eca and Hoekstra [1].
Rheology of complex biobased quaternary blends: Poly(lactic acid) [poly(ethylene oxide)]/poly(ether-b-amide)/poly(amide 11)
Authors: Sangroniz Leire , Gancheva Teodora , Favis Basil D. , Müller Alejandro J. , Santamaria Antxon
Published: April 2021

Linear and nonlinear viscoelastic approaches are used to study multiphase biobased blends of poly(lactic acid), poly(amide 11), poly(ether-b-amide) (PEBA), and poly(ethylene oxide) (PEO) in a wide range of compositions. The novelty of this work resides in (a) the study of hybrid quaternary blends with droplet-matrix as well as cocontinuous morphology, (b) the effect of the PEO and PEBA blend components on the rheological properties, and (c) the investigation of the nonlinear viscoelastic regime for complex hybrid blends. Correlations are established between blend morphology and rheological behavior. Among the different linear rheological approaches, i.e., elastic modulus, complex viscosity, yield stress, Cole–Cole plots, Han plots, and Mavridish–Shroff or Booij–Palmen plots, the latter is the most sensitive allowing extraction of a relaxation time from the plot. The results correlate reasonably well with the different morphologies of the blends. Both, linear and nonlinear methods lead to compatible results, distinguishing among blends with droplet-matrix, partially continuous dispersed phase and fully cocontinuous morphologies. Moreover, for the first time, the analysis of the nonlinear parameter, Q0, allows a qualitative comparison of the interfacial areas of blends with a dispersed phase-matrix morphology at different continuity levels and those with cocontinuous morphology.
Leishmania donovani Metacyclic Promastigotes Impair Phagosome Properties in Inflammatory Monocytes
Authors: Matte Christine , Arango Duque Guillermo , Descoteaux Albert
Published: April 2021

Leishmaniasis, a debilitating disease with clinical manifestations ranging from self-healing ulcers to life-threatening visceral pathologies, is caused by protozoan parasites of the
Leishmania
genus. These professional vacuolar pathogens are transmitted by infected sand flies to mammalian hosts as metacyclic promastigotes and are rapidly internalized by various phagocyte populations.
The RNA Binding Proteins YTHDC1 and FMRP Regulate the Nuclear Export of
N
6
-Methyladenosine-Modified Hepatitis B Virus Transcripts and Affect the Viral Life Cycle
Authors: Kim Geon-Woo , Imam Hasan , Siddiqui Aleem
Published: April 2021

YTHDC1 and FMRP have been recently implicated in the nuclear export of m
6
A modified mRNAs. Here, we show that FMRP and YTHDC1 proteins bind with m
6
A-modified HBV transcripts and facilitate their nuclear export.
Dynamics of the Bacillus subtilis Min System
Authors: Feddersen Helge , Würthner Laeschkir , Frey Erwin , Bramkamp Marc
Published: April 2021

The molecular mechanisms that help to place the division septum in bacteria is of fundamental importance to ensure cell proliferation and maintenance of cell shape and size. The Min protein system, found in many rod-shaped bacteria, is thought to play a major role in division site selection.
Transcriptomics Provides a Genetic Signature of Vineyard Site and Offers Insight into Vintage-Independent Inoculated Fermentation Outcomes
Authors: Reiter Taylor , Montpetit Rachel , Byer Shelby , Frias Isadora , Leon Esmeralda , Viano Robert , Mcloughlin Michael , Halligan Thomas , Hernandez Desmon , Figueroa-Balderas Rosa , Cantu Dario , Steenwerth Kerri , Runnebaum Ron , Montpetit Ben
Published: April 2021

The wine industry generates billions of dollars of revenue annually, and economic productivity is in part associated with regional distinctiveness of wine sensory attributes. Microorganisms associated with grapes and wineries are influenced by region of origin, and given that some microorganisms play a role in fermentation, it is thought that microbes may contribute to the regional distinctiveness of wine.
In Vitro
Gut Modeling as a Tool for Adaptive Evolutionary Engineering of
Lactiplantibacillus plantarum
Authors: Isenring Julia , Geirnaert Annelies , Hall Alex R. , Jans Christoph , Lacroix Christophe , Stevens Marc J. A.
Published: April 2021

Improvement of bacterial strains in regard to specific abiotic environmental factors is broadly used to enhance strain characteristics for processing and product quality. However, there is currently no multidimensional probiotic strain improvement approach for both abiotic and biotic factors of a colon microbiota.
Eruption risks from covert silicic magma bodies
Authors: Rooyakkers Shane M. , Stix John , Berlo Kim , Petrelli Maurizio , Sigmundsson Freysteinn
Published: April 2021

Unintentional encounters with silicic magma at ~2–2.5 km depth have recently occurred during drilling at three volcanoes: Kilauea (Hawaii), Menengai (Kenya), and Krafla (Iceland). Geophysical surveys had failed to warn about shallow magma before each encounter, and subsequent surveys at Krafla have been unable to resolve the size or architecture of its silicic magma body. This presents a conundrum for volcano monitoring: Do such shallow “covert” magma bodies pose an eruption risk? Here, we show that Krafla’s most recent explosive eruption, a mixed hydrothermal-magmatic event in 1724 C.E. that formed the Víti maar, involved rhyolite essentially indistinguishable in composition from magma encountered during drilling in 2009. Streaks of quenched basalt in some Víti pumices provide direct evidence for interaction between co-erupted rhyolitic and basaltic magmas, but crystals in these pumices show no evidence for late-stage heating or re-equilibration with more mafic melt, implying mixing time scales of at most several hours. Covert silicic magma thus presents an eruption risk at Krafla and may be mobilized with little warning. Difficulties in resolving magma bodies smaller than ~1 km3 with geophysical surveys mean that covert silicic magma may exist at many other volcanoes and should be considered in hazard and risk assessments.
Annually resolved sediments in the classic Clarkia lacustrine deposits (Idaho, USA) during the middle Miocene Climate Optimum
Authors: Höfig Daianne , Zhang Yi Ge , Giosan Liviu , Leng Qin , Liang Jiaqi , Wu Mengxiao , Miller Brent , Yang Hong
Published: April 2021

The world-renowned Miocene Clarkia paleolake in northern Idaho (USA) is closely associated with Columbia River Basalt Group volcanism. The flood basalt dammed a local drainage system to form the paleolake, which preserved a plant fossil Lagerstätte in its deposits. However, the precise age and temporal duration of the lake remain unsettled. We present the first unequivocal U-Pb zircon ages from interbedded volcanic ashes at the P-33 type location, constraining the deposition to 15.78 ± 0.039 Ma. Using micro–X-ray fluorescence and petrographic and spectral analyses, we establish the annual characteristics of laminations throughout the stratigraphic profile using the distribution of elemental ratios, mineral assemblages, and grain-size structures, as well as organic and fossil contents. Consequently, the ~7.5-m-thick varved deposit at the type location P-33 represents ~840 yr of deposition, coincident with the end of the main phase of Columbia River Basalt Group eruptions during the Miocene Climate Optimum. The timing and temporal resolution of the deposit offer a unique opportunity to study climate change in unprecedented detail during global warming associated with carbon-cycle perturbations.
‘Long COVID’ syndrome
Authors: Taribagil Priyal , Creer Dean , Tahir Hasan
Published: April 2021

SARS-CoV-2 has resulted in a global pandemic and an unprecedented public health crisis. Recent literature suggests the emergence of a novel syndrome known as ‘long COVID’, a term used to describe a diverse set of symptoms that persist after a minimum of 4 weeks from the onset of a diagnosed COVID-19 infection. Common symptoms include persistent breathlessness, fatigue and cough. Other symptoms reported include chest pain, palpitations, neurological and cognitive deficits, rashes, and gastrointestinal dysfunction. We present a complex case of a previously well 28-year-old woman who was diagnosed with COVID-19. After resolution of her acute symptoms, she continued to experience retrosternal discomfort, shortness of breath, poor memory and severe myalgia. Investigations yielded no significant findings. Given no alternative diagnosis, she was diagnosed with ‘long COVID’.
Active surveillance for carbapenemase-producing Klebsiella pneumoniae and correlation with infection in subjects attending an Italian tertiary-care hospital: a 7-year retrospective study
Authors: Calderaro Adriana , Buttrini Mirko , Martinelli Monica , Montecchini Sara , Covan Silvia , Ruggeri Alberto , Rodighiero Isabella , Di Maio Alan , Galullo Mariapia , Larini Sandra , Arcangeletti Maria Cristina , Chezzi Carlo , De Conto Flora
Published: April 2021

Objectives

The distribution of carbapenemase-producing Klebsiella pneumoniae (CPKP) phenotypes and genotypes in samples collected during 2011–2018 was evaluated. The association between patients with CPKP-positive rectal swab and those with CPKP infection, as well as the overall analysis of CPKP-infected patients, was performed.

Setting

The study was performed in a tertiary-care hospital located in Northern Italy.

Participants

Two groups were considered: 22 939 ‘at-risk’ patients submitted to active surveillance for CPKP detection in rectal swabs/stools and 1094 CPKP-infected patients in which CPKP was detected in samples other than rectal swabs.

Results

CPKP-positive rectal swabs were detected in 5% (1150/22 939). A CPKP infection was revealed in 3.1% (719/22 939) of patients: 582 with CPKP-positive rectal swab (50.6% of the 1150 CPKP-positive rectal swabs) and 137 with CPKP-negative rectal swab. The 49.4% (568/1150) of the patients with CPKP-positive rectal swab were carriers. The overall frequency of CPKP-positive patients (carriers and infected) was almost constant from 2012 to 2016 (excluding the 2015 peak) and then increased in 2017–2018. blaKPC was predominant followed by blaVIM. No difference was observed in the frequency of CPKP-positive rectal swab patients among the different material groups. Among the targeted carbapenemase genes, blaVIM was more significantly detected from urine than from other samples.

Conclusions

The high prevalence of carriers without evidence of infection, representing a potential reservoir of CPKP, suggests to maintain the guard about this problem, emphasising the importance of active surveillance for timely detection and separation of carriers, activation of contact precautions and antibiotic treatment guidance on suspicion of infection.
Painful legs and moving toes
Authors: de Assis Franco Igor , Vale Thiago Cardoso , Schulze Vitor Henrique , Goncalves Marcus Vinicius Magno
Published: April 2021

A 40-year-old woman reported involuntary and irregular movements of her left toes accompanied by pain. This arose following arthroscopy after a sprained left ankle. She had involuntary flexion–extension and abduction and adduction movements of the hallux and the other toes, with reduced pinprick sensation on the skin web between the left hallux and the second toe. Nerve conduction studies confirmed a deep peroneal nerve axonal injury. We diagnosed the syndrome of painful legs and moving toes, provoked by a peripheral nerve injury. Her symptoms have persisted despite pregabalin, gabapentin and amitriptyline.
Maturation reaction norm evolution under varying conditions of eco-evolutionary change
Authors: Gobin Jenilee , Fox Michael G. , Dunlop Erin S.
Published: April 2021

Probabilistic maturation reaction norms (PMRNs) are commonly used to infer evolution of maturation age and size in wild fish stocks, but how well estimates from phenotypic data actually reflect underlying genotypes is debated. We used an eco-genetic model of a commercially harvested freshwater fish to simulate populations undergoing various levels of fisheries-induced evolution and density-dependent feedback and evaluated effects on the estimation of PMRNs. We estimated PMRNs from phenotypic data sampled from simulated populations (age, length, and maturation status of individuals), as is done for wild stocks, and compared estimates with the known maturation genotypes of individuals in the simulated population. PMRN estimates were robust to changes in the strength of density-dependent growth and high levels of fisheries-induced evolution. However, our ability to detect slower rates of evolution was limited, especially when individuals matured within a narrow range of ages. Furthermore, low numbers of immature or mature individuals within a given age class limited our ability to robustly estimate midpoints for more than one or two ages, despite our large sample sizes (n = 200 randomly sampled individuals of each age per year), highlighting a challenge with this approach. Nonetheless, this study suggests that the widely applied method of estimating PMRNs from readily available phenotypic data to detect underlying evolution of maturation schedule is robust to some key factors that vary in wild populations.
Localization and eigenvalue statistics for the lattice Anderson model with discrete disorder
Authors: Imbrie John Z.
Published: April 2021

We prove localization and probabilistic bounds on the minimum level spacing for the Anderson tight-binding model on the lattice in any dimension, with single-site potential having a discrete distribution taking [Formula: see text] values, with [Formula: see text] large. These results hold for all energies under an assumption of weak hopping.
Mixed volume preserving flow by powers of homogeneous curvature functions of degree one
Authors: Guo Shunzi
Published: April 2021

This paper concerns the evolution of a closed hypersurface of dimension [Formula: see text] in the Euclidean space [Formula: see text] under a mixed volume preserving flow. The speed equals a power [Formula: see text] of homogeneous curvature functions of degree one and either convex or concave plus a mixed volume preserving term, including the case of powers of the mean curvature and of the Gauss curvature. The main result is that if the initial hypersurface satisfies a suitable pinching condition, there exists a unique, smooth solution of the flow for all times, and the evolving hypersurfaces converge exponentially to a round sphere, enclosing the same mixed volume as the initial hypersurface.
A 4–6 GHz Single-Ended to Differential-Ended Low-Noise Amplifier for IEEE 802.11ax Wireless Applications with Inherent Complementary Distortion Cancellation
Authors: Chrisben Gladson S. , Siva Prasad P. , Thenmozhi V. , Bhaskar M.
Published: April 2021

With the emergence of the internet-of-things (IoT), many devices process data through the IEEE 802.11 wireless networks. To satisfy the increased data processing, the wireless fidelity (Wi-Fi) networks must have sufficient capacity. IEEE 802.11ax is formulated to provide higher data processing capabilities for IoT applications. The IEEE 802.11ax receiver operating at 5[Formula: see text]GHz must be able to withstand interference from nearby IoT applications. Hence, the low-noise amplifier (LNA) employed in such receivers must have a high input-referred third-order intercept point (IIP3). This paper aims to present a wideband LNA operating at 5[Formula: see text]GHz with high IIP3 for modern IoT transceivers using IEEE 802.11ax protocol. The LNA is designed and implemented in UMC 65[Formula: see text]nm CMOS technology using the Cadence virtuoso design tool. The proposed LNA can provide a maximum gain of 17.64[Formula: see text]dB while consuming 8.18[Formula: see text]mW of power from a 1.2[Formula: see text]V supply. It can be noted that the minimum noise figure (NF) achieved is 3.67[Formula: see text]dB and the corresponding IIP3 is 9.44[Formula: see text]dBm at 5[Formula: see text]GHz from the pre-layout simulations.
PHOTOELECTRON SPECTROSCOPY STUDIES ON Al2O3 FILMS ON p-GaN(0001)
Authors: LEWANDKÓW R. , GRODZICKI M. , MAZUR P.
Published: April 2021

In order to determine its electronic and chemical properties, the Al2O3/p-GaN(0001) interface is studied in situ by the X-ray and ultraviolet photoelectron spectroscopies (XPS and UPS). Using physical vapor deposition (PVD) method, the Al2O3 film is deposited step by step under ultra-high vacuum (UHV) onto p-GaN(0001) surface covered with residual native Ga oxide. Prior to the first Al2O3 layer evaporation, binding energy of the Ga 3[Formula: see text] substrate line is equal to 20.5[Formula: see text]eV. The PVD method of deposition leads to an amorphous Al2O3 film formation. For the final 12.0[Formula: see text]nm thick Al2O3 film binding energy of the Al 2[Formula: see text] line is set at 76.0[Formula: see text]eV and for the O 1[Formula: see text] line at 532.9[Formula: see text]eV. The valence band offset (VBO) and the conduction band offset (CBO) of the Al2O3/p-GaN(0001) interface are determined to be equal to [Formula: see text]1.6[Formula: see text]eV and 1.8[Formula: see text]eV, respectively.
Transverse Vibration Energy Harvesting of Double Elastic Steel
Authors: Wang Yi-Ren , Hung Chien-Chun , Tseng Jung-Ting
Published: April 2021

This study uses the piezoelectric technology to collect vibration energy from the fixed-fixed nonlinear elastic beams attached with the piezo-patch between the two ends. Both single elastic steel sheet (SESS) and double elastic steel sheet (DESS) systems are investigated and correlated. To simulate the power generation of the vibration energy harvester (VEH) of both the SESS and the DESS in different engineering elements, the simple harmonic external force generated by a shaker at the location of the piezo-patch is used as the source. With this, more vibration converted electric energy is derived from the transverse deformation and flapping from the DESS than the SESS beam. The equation of a nonlinear Euler–Bernoulli beam is coupled with the electric energy equation of the piezo-patch to simulate the SESS VEH system. The flapping force from the DESS VEH system can be considered the concentrated external load applied on the SESS beam model. The method of multiple scales (MOMS) is employed to analyze this nonlinear problem. The fixed points plots and the numerical results confirm this theory presented for the two beam systems, which can be used for evaluating similar engineering systems. Experiments are also performed in this study. The Taguchi method is used to analyze the optimum locations of the shaker and piezo-patch, as well as the confidence level of the factors. The method of nonlinear analysis presented in this study demonstrates its accuracy compared with the linear case. The transverse DESS VEH model proposed is proved to be feasible and more effective than the SESS system.
Theoretical results of optimal harvesting in a hierarchical size-structured population system with delay
Authors: He Ze-Rong , Han Mengjie
Published: April 2021

We investigate an optimal control problem for a hierarchical size-structured population model, which incorporates the inoculation delay into the globally feedbacked boundary condition. After the establishment of the continuity of the states with respect to the harvesting efforts, the existence of the optimal solutions is proved by a result in convex analysis, and the maximum principle is obtained via conjugate system and tangent-normal cones.
The minimal speed of traveling wavefronts for a three-component competition system with nonlocal dispersal
Authors: He Juan , Zhang Guo-Bao
Published: April 2021

In this paper, we study the linear determinacy of the minimal speed of traveling wavefronts for a three-component competition system with nonlocal dispersal. We first transform this system into a cooperative system. Then, by constructing suitable upper solutions, we give some general conditions to ensure the linear determinacy of the minimal speed. Finally, we provide some more precise conditions that only rely on the parameters of the system such that the linear determinacy of the minimal speed is assured.
Numerical investigation on effect of various pump rotational speeds on performance of centrifugal pump based on CFD analysis technique
Authors: Al-Obaidi Ahmed Ramadhan
Published: April 2021

In this study, the flow structure and effect of different pump rotational speeds on a centrifugal pump’s performance are experimentally and numerically investigated. The internal flow field pattern within the pump has been analyzed and discussed using the CFD technique. The numerical results are compared with experimental data under a wide range of operating conditions. The comparison results between them have indicated a considerable agreement. The pressure variations are gradually increasing from inlet to outlet impeller of the pump. The results note that when the impeller rotates near the tongue region, the pressure in this region was higher than in other parts. Also, the interaction between the impeller and volute tongue region is actually according to the impeller blades’ relative position concerning the tongue region. Furthermore, the pressure and velocity variations within a centrifugal pump increase with rotational impeller speed.
Modeling and analytical calculation of road damage coefficient considering tire pressure and damping of vehicles
Authors: Ma Jianwei , Wang Wenlong
Published: April 2021

The road damage coefficient [Formula: see text] is a significant indicator to estimate the degree of the road damage caused by vehicles. The existing calculation method of [Formula: see text] is not convenient for the engineering application. To effectively evaluate the damage degree and facilitate the engineering application, this paper studied the simple and reliable analytical calculation method of [Formula: see text]. Firstly, a dynamic model of the vehicle–road system was created. The tire pressure and the tire damping were considered in the model. Moreover, the relationship between the tire vertical stiffness and the tire pressure is approximated as a linear function. Secondly, based on the dynamic model, according to the definition of [Formula: see text], a concise analytical formula of [Formula: see text] was derived and verified by numerical simulations. The relative errors of the analytical calculation results are all less than 0.1%. Thirdly, the influences of the tire pressure [Formula: see text], the damping ratio [Formula: see text] of the suspension system, and the damping ratio [Formula: see text] of the wheel system on [Formula: see text] were analyzed. Moreover, based on the analytical formula of [Formula: see text], a mathematical model of the optimal damping matching for the suspension system was established and a case study was also given. The research results show that the larger the tire pressure [Formula: see text], the larger the value of [Formula: see text] is. For each [Formula: see text], there is an optimal damping ratio [Formula: see text]. If the tire damping is ignored, it will lead to the design error for [Formula: see text]. Finally, some important conclusions were drawn. The analytical formula of [Formula: see text] and the conclusions can provide valuable references for the analysis of the road damage and the initial design of vehicle suspensions.
Digitalization of Shop Floor Management: In Blissful Ignorance of Superfluous Work
Authors: Mathiasen John Bang , de Haas Henning
Published: April 2021

With the purpose of understanding the extent of superfluous work and, thereby, suggesting managerial opportunities for reducing superfluous work, this paper focuses on decision-making processes at the shop floor level in digitalized manufacturing companies. Superfluous work is a kind of hidden waste and comprises the gap between necessary work and the work that is actually carried out, either on handling daily tasks at the shop floor, accomplishing decision-making processes, or implementing workarounds. By using an abductive approach, the research systematically combines a theoretical conceptualization of shop floor decision-making processes in smart-manufacturing with an empirical enquiry into a highly digitalized manufacturing company. The paper reveals superfluous work if the decision-making process involves collaboration across disciplines and/or organizational boundaries. Superfluous work occurs because of a lack of data and information to guide reflective thinking and knowledge sharing. In relation to highly complex decision-making, the ongoing implementation of workarounds also causes superfluous work. Prerequisites for reducing superfluous work are enhancing the accessibility of applicable data to guide reflective thinking and knowledge sharing at the shop floor level.
Characterization of heavy mineral concentrates and detrital gold particles from the Bigorne granite-hosted gold deposit in the Iberian Variscan Belt
Authors: Leal Sara , Lima Alexandre , Noronha Fernando
Published: April 2021

The Bigorne gold deposit, located in the Iberian Variscan belt, is a gold-bearing vein system, which cross-cuts Variscan granites. The hypogene mineralization corresponds to sheet-veins parallel to the late-Variscan Penacova–Régua–Verín fault. A combined study was undertaken of gold particles from hypogene mineralization and locally derived eluvial material, as well as gold from alluvial deposits in local drainages, to assess possible sources of the alluvial gold. The geochemistry and mineralogy of heavy mineral concentrates revealed a similar signature to the hosted granites and hypogene mineralization, which indicates a local source for the surficial materials, with limited contribution from surrounding rocks. Hypogene and detrital gold particles at Bigorne area are entirely primary in origin and correspond essentially to a Au–Ag alloy (<22 wt% Ag), locally with minor amounts of Cu. The compositional range of Ag and Cu is a consequence of variation in parameters formation of the deposit, such as temperature. Our study highlights the first results on gold detrital particles chemistry for granite-hosted gold deposits in the Iberian Variscan belt, and has provided a platform for further work to characterize gold from this environment, such that it may be used as a generic indicator mineral together with other resistant ore minerals.
The Evolution of the Living Environment in Suzhou in the Ming and Qing Dynasties Based on Historical Paintings
Authors: Ding Ding , Yu Xianjun , Wang Zhonglin
Published: April 2021

Some historical paintings are realistic enough to provide information for the study of ancient civil buildings and their corresponding living environment. This article uses architectural iconology, computer modeling, and quantitative analysis methods to interpret ancient images for contemporary research. This work selects
Qingming Shanghe Tu
, painted by Ying Qiu in the Ming Dynasty, and
Gusu Fanhua Tu
, created by Yang Xu in the Qing Dynasty to study the evolution of the living environment of ancient Suzhou at the natural meaning level. At the conventional meaning level, a comparison of the two images reveals that land use, landscaping, building performance, and building materials evolved due to social development. At the intrinsic meaning level, this development was found to be closely related to the expansion of urban construction, the development of compact landscaping, and the maturation of construction techniques. The architectural iconology method proposed by this work can be used to study other ancient buildings based on existing images.
Human Induction in Machine Learning
Authors: Spelda Petr , Stritecky Vit
Published: April 2021

As our epistemic ambitions grow, the common and scientific endeavours are becoming increasingly dependent on Machine Learning (ML). The field rests on a single experimental paradigm, which consists of splitting the available data into a training and testing set and using the latter to measure how well the trained ML model generalises to unseen samples. If the model reaches acceptable accuracy, then an
a posteriori
contract comes into effect between humans and the model, supposedly allowing its deployment to target environments. Yet the latter part of the contract depends on human inductive predictions or generalisations, which infer a uniformity between the trained ML model and the targets. The article asks how we justify the contract between human and machine learning. It is argued that the justification becomes a pressing issue when we use ML to reach “elsewhere” in space and time or deploy ML models in non-benign environments. The article argues that the only viable version of the contract can be based on optimality (instead of on reliability, which cannot be justified without circularity) and aligns this position with Schurz's optimality justification. It is shown that when dealing with inaccessible/unstable ground-truths (“elsewhere” and non-benign targets), the optimality justification undergoes a slight change, which should reflect critically on our epistemic ambitions. Therefore, the study of ML robustness should involve not only heuristics that lead to acceptable accuracies on testing sets. The justification of human inductive predictions or generalisations about the uniformity between ML models and targets should be included as well. Without it, the assumptions about inductive risk minimisation in ML are not addressed in full.
Social Media Identity Deception Detection
Authors: Alharbi Ahmed , Dong Hai , Yi Xun , Tari Zahir , Khalil Ibrahim
Published: April 2021

Social media have been growing rapidly and become essential elements of many people’s lives. Meanwhile, social media have also come to be a popular source for identity deception. Many social media identity deception cases have arisen over the past few years. Recent studies have been conducted to prevent and detect identity deception. This survey analyzes various identity deception attacks, which can be categorized into fake profile, identity theft, and identity cloning. This survey provides a detailed review of social media identity deception detection techniques. It also identifies primary research challenges and issues in the existing detection techniques. This article is expected to benefit both researchers and social media providers.
Performance of Carbon-Nickel Composite Coatings on Laser Surface Roughened Aluminum Foils for Supercapacitor Current Collectors
Authors: Yang Dongfang , Laforgue Alexis
Published: April 2021

Surface-engineered aluminum current collectors were developed through laser-based surface modification methods. Their performances as current collectors in supercapacitors clearly outperformed state-of-the-art carbon-coated commercial foils and were close to ideal gold foils, thanks to the enhanced interfaces provided by their engineered surfaces. Surface modifications included roughening by laser ablation in high vacuum, and coating with a carbon-nickel (C0.97Ni0.03) composite thin film deposited using pulsed laser deposition. The main improvement was obtained after coating the aluminum foil with the carbon-nickel protective layer, which was attributed to the almost pure sp2 bonding state of the carbon and a mostly metallic nickel phase. The surface roughening treatment further decreased the interface resistance by providing a higher contact surface and a better mechanical anchorage of the active materials layer. The combination of laser roughening in vacuum conditions and subsequent deposition of an electronically conductive protective coating was therefore demonstrated as an efficient approach to improve the performance of current collectors for supercapacitors.
The Energy Technology Division
Authors: Fuller Tom
Published: April 2021

Energy technology is the science and technology of energy conversion and storage. The mission of the Energy Technology Division (ETD) is to encourage and stimulate research and development on new and existing technologies that will improve efficiency, reduce energy use, lower costs, and result in a cleaner environment.
Organic Electrochemistry as a Tool for Synthesis: Umpolung Reactions, Reactive Intermediates, and the Design of New Synthetic Methods
Authors: Daniel Little R. , Moeller Kevin D.
Published: April 2021

Because electrochemistry allows for the selective introduction and removal of electrons from organic molecules, it is an ideal tool for reversing the polarity of known functional groups and triggering umpolung reactions.
The Automatic Detection of Pedestrians under the High-Density Conditions by Deep Learning Techniques
Authors: Jin Cheng-Jie , Shi Xiaomeng , Hui Ting , Li Dawei , Ma Ke
Published: April 2021

The automatic detection and tracking of pedestrians under high-density conditions is a challenging task for both computer vision fields and pedestrian flow studies. Collecting pedestrian data is a fundamental task for the modeling and practical implementations of crowd management. Although there are many methods for detecting pedestrians, they may not be easily adopted in the high-density situations. Therefore, we utilized one emerging method based on the deep learning algorithm. Based on the top-view video data of some pedestrian flow experiments recorded by an unmanned aerial vehicle (UAV), we produce our own training datasets. We train the detection model by using Yolo v3, a very popular deep learning model among many available detection models in recent years. We find the detection results are good; e.g., the precisions, recalls, and F1 scores could be larger than 0.95 even when the pedestrian density is as high as

9.0
 

ped

/

m

2

. We think this approach could be used for the other pedestrian flow experiments or field data which have similar configurations and can also be useful for automatic crowd density estimation.
Multiobjective Core Reloading Pattern Optimization of PARR-1 Using Modified Genetic Algorithm Coupled with Monte Carlo Methods
Authors: Shaukat Nadeem , Ahmad Ammar , Mohsin Bukhtiar , Khan Rustam , Khan Salah Ud-Din , Khan Shahab Ud-Din
Published: April 2021

In order to maximize both the life cycle and efficiency of a reactor core, it is essential to find the optimum loading pattern. In the case of research reactors, a loading pattern can also be optimized for flux at an irradiation site. Therefore, the development of a general-use methodology for core loading optimization would be very valuable. In this paper, general-use multiobjective core reloading pattern optimization is performed using modified genetic algorithms (MGA). The developed strategy can be applied for the constrained optimization of research and power reactor cores. For an optimal reactor core reloading design strategy, an intelligent technique GA is coupled with the Monte Carlo (MC) code SuperMC developed by the FDS team in China for nuclear reactor physics calculations. An optimal loading pattern can be depicted as a configuration that has the maximum keff and maximum thermal fluxes in the core of the given fuel inventory keeping in view the safety constraints such as limitation on power peaking factor. The optimized loading patterns for Pakistan Research Reactor-1 (PARR-1) have been recommended using the implemented strategy by considering the constraint optimization, i.e., to maximize the keff or maximum thermal neutron flux while maintaining low power peaking factor. It has been observed that the developed intelligent strategy performs these tasks with a reasonable computational cost.
Doxycycline Hyclate Modulates Antioxidant Defenses, Matrix Metalloproteinases, and COX‐2 Activity Accelerating Skin Wound Healing by Secondary Intention in Rats
Authors: Altoé Luciana S. , Alves Raul S. , Miranda Lyvia L. , Sarandy Mariáurea M. , Bastos Daniel S. S. , Gonçalves-Santos Elda , Novaes Rômulo D. , Gonçalves Reggiani V.
Published: April 2021

The main objective of this study was to investigate the action of doxycycline hyclate (Dx) in the skin wound healing process in Wistar rats. We investigated the effect of Dx on inflammatory cell recruitment and production of inflammatory mediators via in vitro and in vivo analysis. In addition, we analyzed neovascularization, extracellular matrix deposition, and antioxidant potential of Dx on cutaneous repair in Wistar rats. Male animals (n = 15) were divided into three groups with five animals each (protocol: 72/2017), and three skin wounds (12 mm diameter) were created on the back of the animals. The groups were as follows: C, received distilled water (control); Dx1, doxycycline hyclate (10 mg/kg/day); and Dx2, doxycycline hyclate (30 mg/kg/day). The applications were carried out daily for up to 21 days, and tissues from different wounds were removed every 7 days. Our in vitro analysis demonstrated that Dx led to macrophage proliferation and increased N‐acetyl‐β‐D‐glucosaminidase (NAG) production, besides decreased cyclooxygenase‐2 (COX‐2), prostaglandin E2 (PGE2), and metalloproteinases (MMP), which indicates that macrophage activation and COX‐2 inhibition are possibly regulated by independent mechanisms. In vivo, our findings presented increased cellularity, blood vessels, and the number of mast cells. However, downregulation was observed in the COX‐2 and PGE2 expression, which was limited to epidermal cells. Our results also showed that the downregulation of this pathway benefits the oxidative balance by reducing protein carbonyls, malondialdehyde, nitric oxide, and hydrogen peroxide (H2O2). In addition, there was an increase in the antioxidant enzymes (catalase and superoxide dismutase) after Dx exposure, which demonstrates its antioxidant potential. Finally, Dx increased the number of types I collagen and elastic fibers and reduced the levels of MMP, thus accelerating the closure of skin wounds. Our findings indicated that both doses of Dx can modulate the skin repair process, but the best effects were observed after exposure to the highest dose.
Application of Ground Penetrating Radar in Detecting Deeply Embedded Reinforcing Bars in Pile Foundation
Authors: Zhou Daochuan , Zhu Haitang
Published: April 2021

Ground penetrating radar (GPR) has been widely used for nondestructive testings in civil engineering. However, the GPR has not been adequately applied in detecting deeply embedded reinforcing bars, which is usually difficult to be revealed in radar image due to the wave interference and attenuation in large depth penetration. This study presents a new approach for the GPR detection of deeply embedded reinforcing bars in the reinforced concrete pile foundation. The aim of the GPR survey is to determine the existence and the depth of internal reinforcing bars in the pile foundation for solving engineering dispute. Low centre frequency antenna was used in GPR field testing to obtain the reflected raw data. Optimized procedures of digital filtering techniques were applied to process the GPR raw data. The deeply embedded reinforcing bars are revealed in the radar image after the field testing and postprocessing procedures. The depth of the reinforcing bars was estimated based on the hyperbola match method. The GPR test results were validated by the excavation of the pile foundation. The low centre frequency antenna has been found to be essential to obtain the reflected wave signals of deeply embedded reinforcing bars. The optimized processing procedures is useful to identify and display the reinforcing bars in radar image. The combination of low centre frequency antenna and the postprocessing procedures make the detection of deeply embedded reinforcing bars feasible. The proposed GPR testing method has been found to be effective to estimate the depth of deeply embedded reinforcing bars, which provides the key information for solving engineering dispute.
Some Indices over a New Algebraic Graph
Authors: Özalan Nurten Urlu
Published: April 2021

In this paper, we first introduce a new graph

Γ

N

over an extension

N

of semigroups and after that we study and characterize the spectral properties such as the diameter, girth, maximum and minimum degrees, domination number, chromatic number, clique number, degree sequence, irregularity index, and also perfectness for

Γ

N

. Moreover, we state and prove some important known Zagreb indices on this new graph.