bluuebunny/crossref_metadata_2025 huggingface dataset:
Position‐pose measurement of crane sway based on monocular vision
Authors: Xing‐yu Fu , Dan Niu , Qi Li , Jin‐bo Liu
Published: November 2019

The method of spatial positioning and pose measurement using computer vision have been widely used in satellite docking, motion control systems, navigation and guidance areas. A monocular vision measurement method of the telescope's spatial pose based on infrared target was proposed for the crane sway during industrial driving. An experimental system for monocular vision measurement of the crane spreader was established. Through the corresponding relationship between the geometric position of the infrared light spots and the imaging projection, the non‐linear optimisation iterative method was used to solve the spatial pose parameters that were converted into four spreader model parameters. The system was measured under static conditions and dynamic pendulum for accuracy and real‐time analysis. The experimental results show that the system can meet the real time and accuracy requirements of the spatial pose measurement of the crane sway.
Anti‐shake positioning algorithm of bridge crane based on phase plane analysis
Authors: Zhu Yuxuan , Niu Dan , Li Qi , Chen Youcheng , Wei Shuang , Liu Jinbo
Published: November 2019

In this study, the dynamic model of bridge crane system is established based on Lagrange equation. The transfer function of crane running system is derived. A new crane anti‐swaying scheme different from traditional mechanical anti‐shake strategy is proposed and it is based on phase plane analysis algorithm. By the adaptive speed planning method, the industrial grade bridge crane can calculate different motion trajectories online without any off‐line optimisation calculation under the given acceleration and maximum speed limit conditions. At the same time, the industrial grade bridge crane realises the purpose of anti‐sway and positioning of the crane. The field experiment results show that the swing of the crane is obviously suppressed and the positioning accuracy fully meets the industrial requirements when the load of the crane reaches the target position.
Two‐step commutation control of switched reluctance motor based on PWM
Authors: Yu Chuan , Xiao Zhiyao , Huang Yongming , Zhu Yesheng
Published: November 2019

Aiming at the noise suppression of switched reluctance machine (SRM), the two‐step commutation control method is improved. Combining this with pulse width modulation (PWM), the optimisation problem of the switching angle is studied and analysed and given a method to determine the turn‐on angle, the zero‐voltage turn‐off angle and the turn‐off angle of the negative bus voltage online. The control method is verified by MATLAB/Simulink simulation and experimental prototype platform. The results show that this method is simple and effective. It can achieve variable angle control, and can reduce the operating noise of the motor under different speed and load conditions. It has a high application value in the field of switched reluctance motor‐type electric vehicle development.
Die Macht der Worte – Placebo- und Nocebo-Effekte in der Physiotherapie
Authors: Rutten Geert
Published: November 2019

Das „Gute-Kita-Gesetz“ oder die „Respektrente“ – Politiker nutzen immer häufiger Frames, damit die Bürger ihre neuen Gesetze positiv wahrnehmen. Warum auch Physiotherapeuten diese Kommunikationsmethode nutzen sollten, bei der man durch die Formulierung beeinflusst, wie eine Botschaft ankommt, erklärt der niederländische Physiotherapeut Geert Rutten, der seit Jahren intensiv zu Placebo forscht.
Endophytic Microbiota Comparison of Dendrobium huoshanense Root and Stem in Different Growth Years
Authors: Chen Shaotong , Dai Jun , Song Xiangwen , Jiang Xueping , Zhao Qun , Sun Chuanbo , Chen Cunwu , Chen Naifu , Han Bangxing
Published: November 2019

The endophytic microbiome in medicinal plants is rich and diverse, but few studies have followed the endophytic microbiome of medicinal plants in different tissues with their growth. In this study, we examined the endophytic bacterial and fungal community structures associated with both the stem and root compartments of Dendrobium huoshanense at different growth years via high-throughput sequencing of 16S rRNA genes and nrDNA fragments of internal transcribed spacer regions. Results indicated that more diverse prokaryotic and fungal operational taxonomic units were detected in roots than in stems, and the alpha diversity of endophytic prokaryotic significantly differed among the 1-, 2-, and 3-year-old roots. The dominant bacterial phyla Proteobacteria Firmicutes, Actinobacteria, Bacteroidetes, and Acidobacteria, and fungal phyla Ascomycota, Basidiomycota, and Ascomycota were detected in the stems and roots with 3 growth years. Moreover, linear discriminant effect
size analysis revealed 138 differentially abundant taxonomic clades in the bacterial level, and 197 in the fungal level in six groups. Our results provide evidence for endophytic microbiota communities depending on the tissues and growth years of D. huoshanense. The results from this study should be useful to better understand medicinal plant-microbe interactions.
Enantioselective N-Alkylation of Nitroindoles under Phase-Transfer Catalysis
Authors: Trubitsõn Dmitri , Martõnova Jevgenija , Erkman Kristin , Metsala Andrus , Saame Jaan , Kõster Kristjan , Järving Ivar , Leito Ivo , Kanger Tõnis
Published: November 2019

An asymmetric phase-transfer-catalyzed N-alkylation of substituted indoles with various Michael acceptors was studied. Acidities of nitroindoles were determined in acetonitrile by UV-Vis spectrophotometric titration. There was essentially no correlation between acidity and reactivity in the aza-Michael reaction. The position of the nitro group on the indole ring was essential to control the stereoselectivity of the reaction. Michael adducts were obtained in high yields and moderate enantioselectivities in the reaction between 4-nitroindole and various Michael acceptors in the presence of cinchona alkaloid based phase-transfer catalysts. In addition to outlining the scope and limitations of the method, the geometries of the transition states of the reaction were calculated.
The diffusion of opposite opinions in a randomly biased environment
Authors: González-Navarrete Manuel , Lambert Rodrigo
Published: November 2019

We propose a model for diffusion of two opposite opinions. Here, the decision to be taken by each individual is a random variable, which depends on the tendency of the population as well as on its own trend characteristic. The influence of the population trend can be positive, negative, or nonexistent in a random form. We prove a phase transition in the behavior of the proportion of each opinion. Specifically, the mean square proportions are linear functions of time in the diffusive case but are given by a power law in the superdiffusive regime.
Synthetic Weyl points with various planar symmetries in phononic crystals
Authors: Chen Tinggui , Chu Yue , Jiao Junrui , Yu Dejie
Published: November 2019

We present a study on the existence of synthetic Weyl points with various planar symmetries in phononic crystals. We design a set of phononic crystals to display Weyl points at high-symmetry points with different symmetries in both square and honeycomb lattices. We demonstrate that, in a square lattice, double Weyl points are protected by C4 rotation symmetry, while in a honeycomb lattice, they are protected by C3 rotation symmetry. Additionally, we investigated the effects of symmetry on double Weyl points. The results indicate that double Weyl points would split into two single Weyl points along high-symmetry lines if we break the corresponding symmetries. The distributions of Weyl points in various symmetries are presented systematically. Finally, gapless surface states and the robust one-way acoustic transport in a square lattice are demonstrated in a double Weyl system.
Excess electron solvation in ammonia clusters
Authors: Baranyi Bence , Turi László
Published: November 2019

We performed a combination of quantum chemical calculations and molecular dynamics simulations to assess the stability of various size NH3n− ammonia cluster anions up to n = 32 monomers. In the n = 3–8 size range, cluster anions are optimized and the vertical detachment energy of the excess electron (VDE) from increasing size clusters is computed using various level methods including density functional theory, MP2, and coupled-cluster singles doubles with perturbative triples. These clusters bind the electrons in nonbranched hydrogen bonding chains in dipole bound states. The VDE increases with size from a few millielectron volt up to ∼200 meV. The electron binding energy is weaker than that in water clusters but comparable to small methanol cluster VDEs. We located the first branched hydrogen bonding cluster that binds the excess electron at n = 7. For larger (n = 8–32) clusters, we generated cold, neutral clusters by semiempirical and ab initio molecular dynamics simulations and added an extra electron to selected neutral configurations. VDE calculations on the adiabatic and the relaxed anionic structures suggest that the n = 12–32 neutral clusters weakly bind the excess electron. Electron binding energies for these clusters (∼100 meV) appear to be significantly weaker than those extrapolated from experimental data. The observed excess electron states are diffuse and localized outside the molecular frame (surface states) with minor (∼1%) penetration to the nitrogen frontier orbitals. Stable minima with excess electron states surrounded by solvent molecules (cavity states) were not found in this size regime.
On the Jacobi metric for a general Lagrangian system
Authors: Maraner Paolo
Published: November 2019

An explicit expression for the Jacobi metric for a general Lagrangian system is obtained as a series expansion in the square root of the kinetic energy of the system, and the corresponding geodesics are described in terms of an appropriate nonlinear connection and the associated curvature. In the limit of low kinetic energies, the trajectories of motion of any Lagrangian system are very well approximated by the geodesics of an energy dependent Randers metric or, equivalently, by the paths in configuration space of a representative point subject to electromagnetic- and gravitational-like force fields. For higher kinetic energy values, the trajectories of motion are instead the geodesics of a general energy dependent Finsler metric, corresponding also to the paths in configuration space of a representative point subject to a hierarchy of a potentially infinite number of covariant force fields that generalize the electromagnetic and gravitational ones. Some general implications of these findings are discussed.
Ultrafast coherent exciton dynamics in size-controlled perylene bisimide aggregates
Authors: Kang Seongsoo , Kaufmann Christina , Hong Yongseok , Kim Woojae , Nowak-Król Agnieszka , Würthner Frank , Kim Dongho
Published: November 2019

For H-aggregates of perylene bisimide (PBI), it has been reported that upon photoexcitation, an initially delocalized Frenkel exciton is localized by excimer formation. However, in recent studies, the beforehand exciton dynamics preceding the excimer formation was suggested in larger aggregates consisting of at least more than 10-PBI subunits, which was not observed in small aggregates comprising less than four-PBI subunits. This feature implies that the size of molecular aggregates plays a crucial role in the initial exciton dynamics. In this regard, we have tried to unveil the initial exciton dynamics in PBI H-aggregates by tracking down the transient reorientations of electronic transition dipoles formed by interactions between the PBI subunits in systematically size-controlled PBI H-aggregates. The ultrafast coherent exciton dynamics depending on the molecular aggregate sizes can be distinguished using polarization-dependent femtosecond-transient absorption anisotropy spectroscopic measurements with a time resolution of ∼40 fs. The ultrafast decay profiles of the anisotropy values are unaffected by vibrational relaxation and rotational diffusion processes; hence, the coherent exciton dynamics of the PBI H-aggregates prior to the excimer formation can be directly revealed as the energy migration processes along the PBI H-aggregates.
Lead isotopic ratios in the Arctic environment
Authors: Ardini Francisco , Bazzano Andrea , Grotti Marco
Published: November 2019

Environmental contextLead is a toxic trace element, widely distributed in the Arctic environment as the result of both natural and anthropogenic processes. High-precision measurements of lead’s isotopic composition are used to distinguish the possible sources and track the transport pathways of this toxic metal. These measurements can provide unique global information on the history and status of lead contamination.
AbstractPublished data of lead isotopic ratios in the Arctic environment have been gathered in a dataset file (available as supplementary material) and reviewed to summarise the main information obtained for the different environmental compartments (atmosphere, cryosphere, lithosphere, hydrosphere and biosphere). The analytical procedures applied to achieve the precise measurement of this important environmental proxy are also illustrated and discussed. Finally, a general overview of the sources of atmospheric lead across the Arctic is provided.
Enterotoxins can support CAR T cells against solid tumors
Authors: von Scheidt Bianca , Wang Minyu , Oliver Amanda J. , Chan Jack D. , Jana Metta K. , Ali Aesha I. , Clow Fiona , Fraser John D. , Quinn Kylie M. , Darcy Phillip K. , Kershaw Michael H. , Slaney Clare Y.
Published: November 2019

Significance

Regressions of some blood cancer can follow infusion of patients’ own T cells gene-modified to express a chimeric antigen receptor (CAR). These regressions are associated with extensive proliferation and engraftment of CAR T cells. However, for most common solid cancers, CAR T cells encounter antigen in a microenvironment that is immunosuppressive and lacking T cell support, and significant engraftment does not always occur. Here, we deliver enterotoxins or bispecific antibody to provide CAR T cells with support signals from antigen-presenting cells in lymphoid tissue, away from the tumor microenvironment. We demonstrate that this enables CAR T cell activation and proliferation, leading to enhanced responses against solid tumors in mice. This approach could lead to effective treatments for many common cancers.
Atmospheric modeling and source reconstruction of radioactive ruthenium from an undeclared major release in 2017
Authors: Saunier O. , Didier D. , Mathieu A. , Masson O. , Dumont Le Brazidec J.
Published: November 2019

In October 2017 unusual106Ru detections across most of Europe prompted the Institut de Radioprotection et de Sûreté Nucléaire (IRSN) to analyze the event in order to locate the origin and identify the magnitude of the release. This paper presents the inverse modeling techniques used during the event to achieve this goal. The method is based on a variational approach and consists of using air concentration measurements with the ldX long-range dispersion model included in the IRSN’s C3X operational platform. The method made it possible to quickly identify the southern Urals as the most likely geographical origin of the release. Despite uncertainties regarding the starting date of the release, calculations show that it potentially began on 23 September, while most of the release was emitted on 26 September. Among the nuclear plants identified in the southern Urals, the Mayak complex is that from which the dispersion of the106Ru plume is most consistent with observations. The reconstructed106Ru source term from Mayak is ∼250 TBq. In total, it was found that for 72% of the measurements simulated and observed air concentration agreed within a factor of 5. In addition, the simulated deposition of106Ru agrees with the observed deposition. Outside the southern Urals, the simulations indicate that areas with highest deposition values are located in southern Scandinavia and southeastern Bulgaria and are explained by rainfall events occurring while the plume was passing over.
Drastic enhancement of crystal nucleation in a molecular liquid by its liquid–liquid transition
Authors: Kurita Rei , Tanaka Hajime
Published: November 2019

Significance

Contrary to our intuition, even a single-component substance may have more than 2 liquid states. The transition between them is called “liquid–liquid transition (LLT).” Recently, we have accumulated evidence for the presence of LLT. This transition may have a strong influence on crystallization, if it exists below the melting point of the crystal. Here we show that crystal nucleation rate can indeed be enhanced by many orders of magnitude near the spinodal point of LLT. This may be used not only for the control of crystalline morphology but also for searching LLT in a metastable state, which is hidden behind crystallization. Our finding also sheds light on how crystallization and other liquid-state transitions can be coupled.
Adaptive evolution reveals a tradeoff between growth rate and oxidative stress during naphthoquinone-based aerobic respiration
Authors: Anand Amitesh , Chen Ke , Yang Laurence , Sastry Anand V. , Olson Connor A. , Poudel Saugat , Seif Yara , Hefner Ying , Phaneuf Patrick V. , Xu Sibei , Szubin Richard , Feist Adam M. , Palsson Bernhard O.
Published: November 2019

Evolution fine-tunes biological pathways to achieve a robust cellular physiology. Two and a half billion years ago, rapidly rising levels of oxygen as a byproduct of blooming cyanobacterial photosynthesis resulted in a redox upshift in microbial energetics. The appearance of higher-redox-potential respiratory quinone, ubiquinone (UQ), is believed to be an adaptive response to this environmental transition. However, the majority of bacterial species are still dependent on the ancient respiratory quinone, naphthoquinone (NQ). Gammaproteobacteria can biosynthesize both of these respiratory quinones, where UQ has been associated with aerobic lifestyle and NQ with anaerobic lifestyle. We engineered an obligate NQ-dependent γ-proteobacterium,
Escherichia coli
Δ
ubiC
, and performed adaptive laboratory evolution to understand the selection against the use of NQ in an oxic environment and also the adaptation required to support the NQ-driven aerobic electron transport chain. A comparative systems-level analysis of pre- and postevolved NQ-dependent strains revealed a clear shift from fermentative to oxidative metabolism enabled by higher periplasmic superoxide defense. This metabolic shift was driven by the concerted activity of 3 transcriptional regulators (PdhR, RpoS, and Fur). Analysis of these findings using a genome-scale model suggested that resource allocation to reactive oxygen species (ROS) mitigation results in lower growth rates. These results provide a direct elucidation of a resource allocation tradeoff between growth rate and ROS mitigation costs associated with NQ usage under oxygen-replete condition.
Fbxw7 is a driver of uterine carcinosarcoma by promoting epithelial-mesenchymal transition
Authors: Cuevas Ileana C. , Sahoo Subhransu S. , Kumar Ashwani , Zhang He , Westcott Jill , Aguilar Mitzi , Cortez Jeremy D. , Sullivan Stephanie A. , Xing Chao , Hayes D. Neil , Brekken Rolf A. , Bae-Jump Victoria L. , Castrillon Diego H.
Published: November 2019

Uterine carcinosarcoma is an aggressive variant of endometrial carcinoma characterized by unusual histologic features including discrete malignant epithelial and mesenchymal components (carcinoma and sarcoma). Recent studies have confirmed a monoclonal origin, and comprehensive genomic characterizations have identified mutations such asTp53andPten. However, the biological origins and specific combination of driver events underpinning uterine carcinosarcoma have remained mysterious. Here, we explored the role of the tumor suppressorFbxw7in endometrial cancer through defined genetic model systems. Inactivation ofFbxw7andPtenresulted in the formation of precancerous lesions (endometrioid intraepithelial neoplasia) and well-differentiated endometrioid adenocarcinomas. Surprisingly, all adenocarcinomas eventually developed into definitive uterine carcinosarcomas with carcinomatous and sarcomatous elements including heterologous differentiation, yielding a faithful genetically engineered model of this cancer type. Genomic analysis showed that most tumors spontaneously acquiredTrp53mutations, pointing to a triad of pathways (p53, PI3K, and Fbxw7) as the critical combination underpinning uterine carcinosarcoma, and to Fbxw7 as a key driver of this enigmatic endometrial cancer type. Lineage tracing provided formal genetic proof that the uterine carcinosarcoma cell of origin is an endometrial epithelial cell that subsequently undergoes a prominent epithelial–mesenchymal transition underlying the attainment of a highly invasive phenotype specifically driven by Fbxw7.
Language, immigration, and identity
Authors: Criss Marika K.
Published: November 2019

Populism has been on the rise in Europe, especially in the last decade. Finland is no exception, and a populist
party ‘The Finns Party’ has gained momentum since the 2011 parliamentary election. The purpose of this paper is to examine the
discourses of the Finns Party in their official releases on immigration and language in the 2015 parliamentary election. The
socio-politically situated examination draws from Foucauldian Discourse Analysis, especially the concepts of biopower,
biopolitics, racism, governmentality and subject position. In addition, language identity, language ideologies, and populism are
used to discuss how linguistic identity and ideology are perceived and constructed in the data, especially in terms of discourses
of inclusion and exclusion of ethnically Finnish but linguistically non-dominant groups, and immigrants.
‘Effortful’, ‘needy’ and ‘freeloader’
Authors: Tarkiainen Laura
Published: November 2019

This article provides a rhetorical discourse analysis of constructions of unemployed people’s deservingness. Data
consist of transcripts from Finnish parliament members debating the ‘Activation Model for Unemployment Security’, from December
2017. In the analysis, three discursive constructions of unemployed people’s deservingness were identified: an ‘effortful citizen
lacking control’, a ‘needy citizen deserving the welfare state’s reciprocal acts’ and an ‘undeserving freeloader in need of an
attitude adjustment’. Analysis focuses on how deservingness and undeservingness are rhetorically accomplished and treated as
factual in parliament members’ accounts. The analysis pays particular attention to the question of how speakers build factuality
through the management of categories, extreme case formulations, ‘truth talk’ and maximisation and minimisation strategies. The
results reflect the negotiated nature of deservingness as well as varying constructions of unemployed people’s responsibility in
the contemporary Nordic welfare state context.
eLex2
Authors: Szemińska Weronika , Więch Adrian
Published: November 2019

The article reports on the eLex2 project, which involves designing dictionary software adjusted to the
specific needs of legal translators. On the basis of a careful analysis of target user needs and the characteristics of the
discipline involved, we defined a set of parameters that should be met by the final product. The resulting prototype offers a
number of novel solutions, including a division into sub-dictionaries assigned to different problem complexes in translation, a
classification of headwords according to their relations of equivalence with parallel institutions in the secondary legal system,
or a special classification of equivalents. The ultimate goal is to make available an application that can be used for compiling
and publishing law dictionaries for translators working in various language pairs.
Dialogues with the Dead: Necropoetics of
Zahra’s Paradise
Authors: Shams Fatemeh
Published: November 2019

What can the poetry chosen for epitaphs on
graves tell us about the political and cultural
development of post-revolutionary Iran and the
politics of death and dying under the Islamic
Republic? This article explores contemporary
Persian epitaph poetry as a valuable medium for
understanding the socio-political dynamics of
Iranian society. By analyzing the epitaphs of the
Iran–Iraq war martyrs, who are buried in Zahra’s
Paradise public cemetery in Tehran
(Behesht-e Zahra), a
new nomenclature can be established for the
religious, political and socio-cultural ideas
underpinning death and the afterlife.
Development of anthropometric characteristics in professional Rugby League players: Is there too much emphasis on the pre‐season period?
Authors: Morehen James C. , Clarke Jon , Batsford Jake , Highton Jamie , Erskine Robert M. , Morton James P. , Close Graeme L.
Published: November 2019

Rugby League is a team sport requiring players to experience large impact collisions, thus requiring high amounts of muscle mass. Many players (academy and senior) strive to increase muscle mass during the pre‐season, however, quantification of changes during this period have not been thoroughly investigated. We therefore assessed changes in body‐composition using Dual X‐Ray Absorptiometry (DXA) in eleven academy players over three successive pre‐seasons and ninety‐three senior players from four different European Super League clubs prior to, and at the end of, a pre‐season training period. There was no meaningful change in lean mass of the academy players during any of the pre‐season periods (year 1 = 72.3 ± 7.1–73.2 ± 7.2kg; ES 0.05, year 2 = 74.4 ± 6.9–75.5 ± 6.9kg; ES 0.07, year 3 = 75.9 ± 6.7–76.8 ± 6.6kg; ES 0.06) with small changes only occurring over the three‐year study period (72.3–75.9kg; ES = 0.22). Senior players showed trivial changes in all characteristics during the pre‐season period (total mass = 95.1–95.0kg; ES −0.01, lean mass = 74.6–75.1kg; ES 0.07, fat mass = 13.6–12.9kg; ES −0.17, body fat percentage = 14.8–14.1%; ES −0.19). These data suggest that academy players need time to develop towards profiles congruent with senior players. Moreover, once players reach senior level, body‐composition changes are trivial during the pre‐season and therefore teams may need to individualise training for players striving to gain muscle mass by reducing other training loads.
The impact of the crust equation of state on the analysis of GW170817
Authors: Gamba R , Read J S , Wade L E
Published: November 2019

The detection of GW170817, the first neutron star-neutron star merger observed by Advanced LIGO and Virgo, and its following analyses represent the first contributions of gravitational wave data to understanding dense matter. Parameterizing the high density section of the equation of state of both neutron stars through spectral decomposition, and imposing a lower limit on the maximum mass value, led to an estimate of the stars’ radii of

km and

km (Abbott et al 2018 Phys. Rev. Lett. 121 161101). These values do not, however, take into account any uncertainty owed to the choice of the crust low-density equation of state, which was fixed to reproduce the SLy equation of state model (Douchin and Haensel 2001 Astron. Astrophys. 380 151). We here re-analyze GW170817 data and establish that different crust models do not strongly impact the mass or tidal deformability of a neutron star—it is impossible to distinguish between low-density models with gravitational wave analysis. However, the crust does have an effect on inferred radius. We predict the systematic error due to this effect using neutron star structure equations, and compare the prediction to results from full parameter estimation runs. For GW170817, this systematic error affects the radius estimate by 0.3 km, approximately

of the neutron stars’ radii.
A novel Cerenkov luminescence tomography approach using multilayer fully connected neural network
Authors: Zhang Zeyu , Cai Meishan , Gao Yuan , Shi Xiaojing , Zhang Xiaojun , Hu Zhenhua , Tian Jie
Published: November 2019

Cerenkov luminescence tomography (CLT) has been proved as an effective tool for various biomedical applications. Because of the severe scattering of Cerenkov luminescence, the performance of CLT remains unsatisfied. This paper proposed a novel CLT reconstruction approach based on a multilayer fully connected neural network (MFCNN). Monte Carlo simulation data was employed to train the MFCNN, and the complex relationship between the surface signals and the true sources was effectively learned by the network. Both simulation and in vivo experiments were performed to validate the performance of MFCNN CLT, and it was further compared with the typical radiative transfer equation (RTE) based method. The experimental data showed the superiority of MFCNN CLT in terms of accuracy and stability. This promising approach for CLT is expected to improve the performance of optical tomography, and to promote the exploration of machine learning in biomedical applications.
Improved localized surface plasmon resonance responses of multi-metallic Ag/Pt/Au/Pd nanostructures: systematic study on the fabrication mechanism and localized surface plasmon resonance properties by solid-state dewetting
Authors: Sui M , Kunwar S , Pandey P , Pandit S , Lee J
Published: November 2019

Multi-metallic nanoparticles (NPs) can offer dynamic and tunable localized surface plasmon resonance (LSPR) properties that are suitable for various catalysis, sensing and energy harvesting applications due to the wide range of tunability and applicability. In this work, the systematic fabrication and improved LSPR characteristics of multi-metallic alloy NP arrays are demonstrated based on the solid-state dewetting (SSD) of multi-layers of Ag/Pt/Au/Pd on sapphire (0001). The evolution of surface NPs in terms of configurational and elemental specifications yields vary strong and dynamic LSPR bands in the UV and VIS wavelengths based on the excitation of various plasmonic modes, i.e. dipolar (DR), quadrupolar (QR), multipolar (MR) and higher order (HO) bands, which is further exploited by the finite difference time domain simulations. Through the systematic control of multi-layer thickness, layer ratio and growth conditions, various nanostructures such as voided nanoclusters, network-like NPs and isolated semispherical NPs are obtained, which are unique in terms of morphology and elemental composition at each stage of dewetting process. The growth mechanism of multi-metallic alloy NP arrays is proposed based on the temperature driven thermal diffusion, alloying, Rayleigh-like instability and energy minimization mechanisms. Due to the subsequent sublimation of Ag atoms at above 650 °C, a sharp alteration in the elemental and morphological characteristics is demonstrated. In specific, the high percentage of Ag alloy NPs exhibits strong LSPR bands and gradually weakened along with the Ag sublimation. At the same time, however, the alloy or mono-metallic NPs without Ag still demonstrate much stronger LSPR bands as compared to the monometallic NPs by the SSD of pure films.
Acoustic characteristics of pulse detonation engine sound propagating in enclosed space*
Authors: Kang Yang , Li Ning , Weng Chun-Sheng , Huang Xiao-Long
Published: November 2019

Acoustic characteristics of pulse detonation engine (PDE) sound propagating in enclosed space are numerically and experimentally investigated. The finite element software LS-DYNA is utilized to numerically simulate the PDE sound propagating in enclosed space. Acoustic measurement systems are established for testing the PDE sound in enclosed space, and the time-frequency characteristics of PDE sound in enclosed space are reported in detail. The experimental results show that the sound waveform of PDE sound in enclosed space are quite different from those in open space, and the reflection and superposition of PDE sound on the walls of enclosed space results in the sound pressure oscillating obviously. It is found that the peak sound pressure level (PSPL) and overall sound pressure level (OASPL) of PDE sound in enclosed space are higher than those in open space and their difference increases with the rise of propagation distance. The results of the duration of PDE sound indicate that the A duration of PDE sound in enclosed space is higher than that in open space except at measuring points located at 2-m and 5-m while the B duration is higher at each of all measuring points. Results show that the enclosed space has a great influence on the acoustic characteristic of PDE sound. This research is helpful in performing PDE experiments in enclosed laboratories to prevent the PDE sound from affecting the safety of laboratory environment, equipment, and staffs.
Surface Majorana flat bands in j = 3/2 superconductors with singlet-quintet mixing
Authors: Yu Jiabin , Liu Chao-Xing
Published: November 2019

Recent experiments [Science Advances
4 eaao4513 (2018)] have revealed the evidence of nodal-line superconductivity in half-Heusler superconductors, e.g., YPtBi. Theories have suggested the topological nature of such nodal-line supercon-ductivity and proposed the existence of surface Majorana flat bands on the (111) surface of half-Heusler superconductors. Due to the divergent density of states of the surface Majorana flat bands, the surface order parameter and the surface impurity play essential roles in determining the surface properties. We study the effect of the surface order parameter and the surface impurity on the surface Majorana flat bands of half-Heusler superconductors based on the Luttinger model. To be specific, we consider the topological nodal-line superconducting phase induced by the singlet-quintet pairing mixing, classify all the possible translationally invariant order parameters for the surface states according to irreducible representations of C
3v
point group, and demonstrate that any energetically favorable order parameter needs to break the time-reversal symmetry. We further discuss the energy splitting in the energy spectrum of surface Majorana flat bands induced by different order parameters and non-magnetic or magnetic impurities. We propose that the splitting in the energy spectrum can serve as the fingerprint of the pairing symmetry and mean-field order parameters. Our theoretical prediction can be examined in the future scanning tunneling microscopy experiments.
Optimal sea floor placement of the oil/gas production equipment
Authors: Arsenyev-Obraztsov S S , Ermolaev A I , Kuvichko A M
Published: November 2019

In the construction designing of oil field surface facilities, exists a problem of the seabed production equipment optimal placement. As an initial approximation, we can represent this task in the form of the linear Boolean programming problem. An application of routine methods of discrete programming can theoretically give the desired solution. However, these methods do not take into account the specific nature of the problem. This problem belongs to the NP class. So we can run into significant computational difficulties. This situation is typical for construction of the ground surface or subsea located facilities for real oil/gas fields. To overcome it, we propose to replace a discrete programming model with a linear programming one, which takes into account problem-specific properties. Also, we present examples of the application of the proposed parallel optimization algorithms. Input data for them: the seabed profile, geometry, and space distribution of oil/gas reserves. Optimization problem objective function is the penalty for the irrational placement of seabed production equipment elements.
Mechanical behavior of aluminum honeycomb sandwich structures under extreme low temperature conditions
Authors: Zaoutsos S P
Published: November 2019

The current study is an effort to characterize the mechanical response of panels that are used as structural elements at low temperature applications. For the above reason, plaques of aluminum honeycomb sandwich were exposed for a certain period of time at different low temperature profiles ranging from 23°C to -70°C so that possible variation of their mechanical properties due to temperature exposure to be justified. Four different temperatures namely 23°C, 0°C, -40°C and -70°C were applied to these plaques prior mechanical testing that was performed at different loading modes. Specimens were obtained from these plaques in order to study the effect of low temperature on mechanical behavior and damage response of the specific sandwich structures. Extensive mechanical testing was carried out by means of tensile, compression and bending loading and the respective mechanical properties occurring from these tests were determined. From the results occurring from experimental data obtained from mechanical testing it is evident that there is a moderate decrease of ultimate strength and yield strength of the material as service temperature decreases in tensile, edgewise and flatwise compression as well as in three point bending loading modes. Moreover a drop in temperature results in a decrease in strain at rupture at tensile and compression loading.
Flexural dynamic behavior of submerged cylindrical structures under wave loads
Authors: Giotis T , Pavlou D , Belibassakis K A
Published: November 2019

An analytical solution for the dynamic response of submerged slender circular cylindrical structure subjected to linear wave loads is presented. A double Laplace transform with respect to temporal and spatial variables is applied both to motion equation and boundary conditions. The dynamic deflection of the beam is obtained by inversion of the Laplace transform. The latter with respect to spatial variable is obtained analytically, while the one concerning the temporal variable is numerically calculated using Durbin numerical scheme. Results in the case of a representative example for a monopile foundation subjected to Airy waves are presented and discussed, and the analytical result is compared against numerical dynamic and static solutions.
Machine learning in reservoir permeability prediction and modelling of fluid flow in porous media
Authors: Zolotukhin A B , Gayubov A T
Published: November 2019

Reliable data on the properties of the porous medium are necessary for the correct description of the process of displacing hydrocarbons from the reservoirs and forecasting reservoir performance. The true permeability of the reservoir is one of the most important parameters which determination is time-consuming, costly and require skilled labor. The paper describes the methodology for determining the permeability of a porous medium, based on machine learning. The results of laboratory experiments, available in the database (terrigenous reservoirs with permeability in the range from 12 to 1132 md), are used to train the neural network, and then to predict the reservoir permeability. Comparison of the predicted and calculated permeability values showed a fairly good match between them with the determination coefficient of 0.92. The last task considered in this paper is to obtain an analytical expression describing a fluid flow in a porous medium using machine learning. This procedure enabled to obtain a resultant equation of fluid flow in a wide range of reservoir parameters and pressure gradients, which can be used in reservoir simulators.
Strength analysis of 3D printed carbon fibre reinforced thermoplastic using experimental and numerical methods
Authors: Ghebretinsae F , Mikkelsen O , Akessa A D
Published: November 2019

A study of strength of composite materials produced by 3D printing technology is presented. The samples fabrication and tests to determine the strength both in bending and in tension of the composite materials have been carried out. The composite samples were additively manufactured using Markforged® 3D printer of type Mark-Two. The fabricated composite samples were of carbon fiber filament combined with a thermoset plastic matrix, by its producer named “Onyx”. The tests provided sample mean value for the ultimate tensile strength of 560 MPa and the tensile modulus of 25 GPa. Based on the three point bending tests the ultimate flexural strength of 271 MPa and flexural modulus of 16 GPa were estimated. The tests are reported and discussed in view of stress analysis modeling the layered composite with finite element models.
Numerical study on the ventilation performance of a livestock house built in porous panels in Cold Regions
Authors: Xu Y , Mustafa M Y , Calay R K , Sørensen B R
Published: November 2019

This paper presents a numerical prediction on the assessment of natural ventilation on a livestock house built in porous panels, aided by Computational Fluid Dynamics techniques. A typical climatic environment in Cold Regions was taken into consideration. The ventilation performances have been assessed by the distribution of indoor air velocity, turbulence intensity and local mean age of air through the cases: the house without porous panels, with wind erosion porous panels, and with snow erosion porous panels. The study has found that the porous panels improve the indoor environment in term of the reduction of air velocity and turbulence, and the wind erosion panel performs better than the snow erosion panel. However, applying porous panels may have negative effects on air exchange effectiveness. The presented numerical model is easy to be constructed, flexible to investigate different case scenarios, and quick and cheap to get solutions.
Fatigue design challenges: Recent linear and nonlinear models
Authors: Pavlou D G
Published: November 2019

Reliable fatigue design rules affect the proactive identification of safety parameters in engineering structures. Numerous fatigue crack initiation and propagation models, linear and nonlinear, have been developed for designing purposes or estimation of the remaining life of aging structures. Depending on the adopted assumptions, the accuracy varies for different loading histories, loading types, and materials. Semi empirical models are simple but yield significant inaccuracies. Models with better theoretical basis provide better accuracy, but implementation in real conditions is problematic. In the present work, a review of author’s recent fatigue crack initiation and propagation models based on physical mechanisms is presented and improvements are proposed. Verification of the models on test results is provided and discussed.
Buckling capacity of simulated patch corroded tubular columns – laboratory tests
Authors: Vo T , Hestholm K , Ersdal G , Oma N , Sivertsvik M
Published: November 2019

This paper presents the experimental test results for the buckling capacity of tubular columns exposed to simulated unsymmetrical patch corrosion damage. These tests were performed to investigate how the results of these experiments compare with the capacities obtained for the formulae provided in the 2004 revision of NORSOK N-004. Formulae for patch corroded tubular columns are needed in standards and as such it is unfortunate that these formulae are removed from the present revision of the NORSOK N-004 standard. Prior to suggesting introducing these previous formulae in standards, experimental tests to confirm good correlation between experiments and formulae are needed. The tests performed in this work are presented in this paper for 100% (intact columns), 69%, 34% and 0% remaining wall thickness in the patch.
Inspection planning for fatigue cracks in offshore structures by Monte Carlo simulations
Authors: Neeraas H , Ersdal G , Oma N , Hellevig N-Ch
Published: November 2019

Probability-informed inspection planning has traditionally a tendency to produce longer inspection intervals for older structures in contrast with the intuitive assumption that shorter inspection intervals are needed. In this paper an alternative method for probability-informed inspection planning is suggested based on a parameter updating rather than the general updating used in most cases. The proposed method produces constant inspection intervals after the theoretical first inspection. Further, the method produces reasonable inspection intervals more or less in line with what is used in practise in the offshore industry at present.
Acceptable fatigue crack occurrence rate
Authors: Vårdal O T , Moan T
Published: November 2019

In fatigue management, it is essential to know the fatigue crack growth potential. The lessons learned from use of refined fatigue analyses, fracture mechanics and probabilistic methods for platforms in-service are presented. For ageing offshore units of semi-submersible design, the inspection history of more than 20 000 NDT inspections and detection of close to 1000 fatigue cracks, are used in this study. These experience data are used to assess the fatigue failure potential. The fatigue crack growth capacities are influenced by the extent of gross errors in the design, construction and operation phase in addition to the normal uncertainties of design, construction and inspection. Corrosion in combination with not detected weakening of the capacity against fatigue crack growth is one of the main challenges. Assessments based on collected in-service observations are mandatory.
An efficient approach for ship collision design of reinforced concrete pontoon walls
Authors: Sha Y , Amdahl J , Yang K
Published: November 2019

This paper presents an efficient method for collision design of prestressed concrete pontoon walls. High fidelity finite element models of a container ship bow and a prestressed concrete pontoon wall are first established. Integrated numerical simulations are conducted to study the structural deformation of the pontoon wall during the collision. Parametric studies are also carried out to investigate the effect of the pontoon wall thickness. Based on the failure mode of the pontoon wall, a punching shear check procedure is proposed. This method yields a good accuracy while significantly reduces computational efforts. Hence, the proposed approach can be used for collision analysis in the preliminary design phase of floating pontoons.
Development of a method for evaluation of measures used for winterization of offshore facilities and units
Authors: Jacobsen S R , Viddal S , Dørum K G , Gudmestad O T , Wiencke H S
Published: November 2019

The environmental conditions in the Barents Sea include low temperatures, wind, snow and precipitation influencing safety, working environment, operations and equipment functionality. The conditions are not extreme compared to other Arctic areas, however they do necessitate protection and winterization of the facility. A study performed for the Petroleum Safety Authority (PSA) in 2016 identified known measures for winterization of facilities in the Barents Sea. The study found uncertainties related to the effect the measures have on winterization when considering environmental conditions. Further work was recommended to evaluate the effect of measures when considering performance influencing factors. A new study was initiated by PSA to develop a method to evaluate the efficiency of measures and a means to document the results. The method considers how well a measure achieves a specific safety and winterization goal, effect of the measure on energy consumption, effect of the measure on investment cost and operating cost, and vulnerability of the measure, including operational and organizational factors. In order to refine and test the method, it was applied to case studies considering a year-round production facility, a light well intervention vessel and a drilling facility used in the winter season in the Barents Sea. The paper is not intended to be a research paper but is a presentation of a method that has been developed to perform an initial evaluation of the effectiveness of winterization methods.