bluuebunny/crossref_metadata_2025 huggingface dataset:
Modelling the cyclic influence of climate change on the world economic system
Authors: Zaytsev Andrey , Konnikov Evgeniy , Asaturova Yuliya , Didenko Svetlana
Published: November 2020

Global climate change has become one of the central problems of the world economy over last decades. Its impact on the economy forces it to adapt to the new conditions. Increasing carbon dioxide (CO2) emissions, resulting in the greenhouse effect, depletion of natural resources, pollutions and health problems directly caused by achievements of the industrial revolution have been catastrophic for the environment. The object of the research in this work is the world economic system. The aim of the research is to analyze the factors affecting climate change and to produce recommendations for preventing the negative impact of human economic activity on the world economic system. As a result of the research, four basic econometric models have been built: 1) dependence of temperature change on CO2 emissions; 2) dependence of the number of disasters on temperature change; 3) dependence of the world GDP on the number of disasters; 4) dependence of CO2 emissions on GDP. According to the results of econometric research, this study obtained working conceptual model, which describes cyclic influence of the four interrelated factors, forming a closed system. Thus, the work proves that there is a cyclic relationship between climate change and the state of the world economy.
Recovery of valuable metals from mining and mineral processing waste
Authors: Panayotova Marinela , Panayotov Vladko
Published: November 2020

Ammonia-thiosulfate-copper leaching, aided by a direct current electrochemical impact, is proposed to extract gold (Au), silver (Ag) and copper (Cu) from old flotation tailings mixed with waste rock. Over 80 % of Au available in the waste material and over 75 % of Cu and Ag were extracted into the pregnant leach solution (PLS) at room temperature. Electrowinning from that PLS recovered around 92 % of Au and Cu, and about 87 % of Ag in the cathode deposit that is suitable for further metallurgical refining. The results are better, compared to leaching in the same system but without electrochemical impact and at air addition. The proposed direct current aided method is promising and more environmentally friendly compared to cyanide and even to sodium thiosulfate leaching.
An experimental approach to exploring the feasibility of unmanned aerial vehicle and thermal imaging in terrestrial and arboreal mammals research
Authors: Rahman Dede Aulia , Setiawan Yudi , Wijayanto Arif K , Rahman Ahmad Abdul Aziz Fathur , Martiyani Trisna Rizky
Published: November 2020

The visual camouflage of many species living in the dense cover of the tropical rainforest become obstacles to conducting species monitoring. Unmanned aerial vehicles (drones) combined with thermal infrared imaging (TIR) can rapidly scan large areas from above and detect wildlife that has a body temperature that contrasts with its surrounding environment. This research tested the feasibility of DJI Mavic 2 Enterprise Dual with FLIR as aerial survey platforms to detect terrestrial and arboreal mammals in the five tree density classes in the remaining natural environment on the IPB University campus. This study demonstrated that large-size terrestrial mammal thermal signatures are visible in sparse vegetation at daytime and in the area under the canopy at night monitoring. In contrast, arboreal mammals were better detected in at early morning and night. Survey timing highly influenced the results – the best quality thermal images were obtained at sunrise, late evening, and at night. The drones allow safe operation at low altitudes with low levels of disturbance to animals. Both terrestrial and arboreal mammals are well detected and easily identified when the drone is flying at an altitude < 50 m HAGL. Our preliminary results indicated that thermal surveys from drones are a promising method.
Unsustainable management of wastewater and brewing effluents: The impacts on socioeconomy and environment, Lagos and Niger Delta region, Nigeria
Authors: Henry Chukwuma Oruche , Donatus Anayo Okpara
Published: November 2020

Wastewater mismanagement poses a threat to economic growth and long term prosperity of many countries around the world specially developing ones. Waste is regarded as redundant products, with no marginal value by the owner but impact negatively to the environment and human well-being. Wastewater treatment or reuse does not only improve the promotion of environment and healthy ecosystems but sustains it for long period. Sustainable wastewater management is crucial especially in Niger Delta where water scarcity is enormous. Socio-economic importance of wastewater control especially by municipals, brewery and industries cannot be overemphasized. Though combinations of effluents, oil spills, etc. contribute over 95% of environmental pollution in Nigeria, our focus is on inefficiency of wastewater treatment plants. This study examines the exposure of poor management of wastewater, brewery effluents in Niger delta eco-zones and Lagos state. Multiple Exposure, Multiple Effects (MEME) descriptive method of analysis was used. Based on expository founding that humans, flora and fauna were exposed to the danger of wastewater pollutions in both regions. Conclusion was made based on government priority. The study will be beneficial to brewery industries, government monitoring agencies/institutions, researchers for further improvement especially in the area of mind-set change.
Satellite imagery detection of land destruction in Klapanunggal Karst Landscape induced by limestone surface mining
Authors: Arif Pambudi Ridwan , Bahtiazhar Rodhial Falah Ahmad , Naldi Ari , Falahiyyah Bahri Nurul , Viandari Kharti Irene Swastiwi , Akbar Hariadi Muhammad , Luthfi Ade
Published: November 2020

Limestone mining activities in the Klapanunggal Karst Landscape were carried out at surface level. This method induced several adverse impacts on the environment. This study aimed to detect land destruction in the Klapanunggal Karst Landscape triggered by open limestone mining on the surface in the 2014-2020 period. The supervised classification method of Maximum Likelihood Estimation (MLE) was used to detect the change in land cover from Landsat 8 imagery, and Differential Interferometric Synthetic Aperture Radar (DInSAR) was applied to detect the change in landform from Sentinel 1A imagery. As a result, between 2014 to 2020, open limestone mining in the Klapanunggal Karst Landscape was confirmed to have a significant impact on the land cover changes in Klapanunggal, from an area with full of vegetation to a mining area with 4.0 x 106m2wide, and eroded landform with a dominant land deformation rate in the range of -47.75 to -39.50 cm/year and -39.50 to -31.25 cm/year. The limestone mining activity in the period of 2014 2020 was estimated to have mined limestone with a volume of 30.7 x 106m3. Limestone surface mining has destructed Klapanunggal Karst Landscape, further research was needed to examine the adverse impacts on the hydrogeological system.
Influence of the level of development of the digital environment on the trend of gross domestic product in the countries of the European Union
Authors: Andrey Zaytsev , Evgeniy Konikov , Yulia Busheneva , Zarema Doleva
Published: November 2020

The paper characterizes the specifics of the impact of digitalization processes on such an indicator as GDP per capita: case study of the European Union countries. The literature dedicated to the matters of the relationship between digitalization and economic growth is reviewed. Based on the statistical data, a regression model is built to determine the dependencies between the GDP of European Union member countries and the economic digitalization indicators. An equation formed in the research can be used to demonstrate the dependence between GDP per capita and the accessibility of information and communications technology and its usage by organizations, households, and private persons in the territory of the European Union. According to the result obtained, the following possible options were formulated for the development of the European Union economies concerning digitalization: stimulating the introduction of information and communications technology in enterprises (including tax incentives for the firms involved in entrepreneurial digital development, as well as growing investments in the existing assets), households (increasing trust of the population in digital products; increasing human capital, which is highly demanded by the digital economy; prospects of the electronic postal trade system); focus on the export of high-tech products.
Strategic policy of companies in the area of social responsibility: Covid-19 challenges
Authors: Drobyazko Svetlana , Hilorme Tetiana , Solokha Dmytro , Bieliakova Oksana
Published: November 2020

COVID 19 is a litmus test for TNCs in the field of social responsibility. A scientific and methodological approach to determining the level and activation of corporate social responsibility (CSR) of business in the national economy in the form of a three-dimensional matrix model of positioning the level of development of CSR of business units in the coordinate system: social, environmental and economic components of CSR has been developed. The methods used in the study, the construction of the Gibbs Triangle and the method of taxonomy to determine the most influential aspects of GRI reporting (G4), allowed to propose a CSR monitoring system for key business performance indicators. The results of the analysis of this study allow distinguishing five areas of responsibility: the necessary level of responsibility - for statutory obligations, the developed level - active charitable and sponsorship, high level - responsibility to internal and external stakeholders, strategic - focus on the social investment state level, as well as synergetic - a comprehensive combination of all components of the CSR. In conclusion, the level and activation of corporate social responsibility of industrial enterprises in the form of a three-dimensional matrix model of positioning the level of development of business units in the coordinate system: social, environmental, and economic components, has been determined to develop alternative scenarios to justify management decisions.
UAV application to estimate oil palm trees health using Visible Atmospherically Resistant Index (VARI) (Case study of Cikabayan Research Farm, Bogor City)
Authors: Nur Anisa Medina , Rokhmatuloh  , Hernina Revi
Published: November 2020

This article describes the making of an oil palm tree health map using aerial photos extracted from UAV DJI Phantom 4. A DJI Phantom 4 was flown at 100 meters height at the Cikabayan Research Farm, Bogor City. Raw aerial photos from DJI Phantom 4 were processed using Agisoft Photoscan software to generate dense point clouds. These points were computed to produce a digital surface model (DSM) and orthophotos with a spatial resolution of 2.73 cm/pixel. Red, green, and blue bands of the photos were computed to provide the Visible Atmospherically Resistant Index (VARI). Also, orthophotos containing oil palm trees were digitized to create points in vector form. VARI pixel values were added to each point and classified into four classes: Needs Inspection, Declining Health, Moderately health, and Healthy. Resulted oil palm tree health map reveals that most of the oil palm trees in the study location are classified as Declining Health and Needs Inspection. Profitably, plantation workers can directly inspect oil palm trees whose health are declining, based on information derived from oil palm tree health map. The information that comes from this study will significantly save time and effort in monitoring oil palm trees’ healthiness.
Impact of Zn(II) ions on crystallization and thermal properties of Poly(lactic acid)
Authors: Wang Zan , Liu He-wen
Published: November 2020

The issues of low crystallinity and slow crystallization rate of poly(lactic acid) (PLA) have been widely addressed. In this work, we find that doping PLA with Zn(II) ions can speed up the process of crystallization of PLA. Three kinds of Zn(II) salts (ZnCl2, ZnSt and ZnOAc) were tested in comparison with some other ions such as Mg(II) and Ca(II). The increased crystallinity and crystallization rate of PLA doping with Zn(II) are reflected in FT-IR and variable temperature Raman spectroscopy. The crystallinity is further confirmed or measured with differential scanning calorimetry and X-ray diffraction. The crystallinity rate of the PLA/ZnSt-0.4 wt% material can reach 22.46% and the crystallinity rate of the PLA/ZnOAc-0.4 wt% material can reach 24.83%, as measured with differential scanning calorimetry.
Physical properties of Si2Ge and SiGe2 in hexagonal symmetry: First-principles calculations
Authors: Zhao Ying-bo , Lin Shi-xuan , Fan Qing-yang , Zhang Qi-dong
Published: November 2020

We predict two novel group 14 element alloys Si2Ge and SiGe2 in P6222 phase in this work through first-principles calculations. The structures, stability, elastic anisotropy, electronic and thermodynamic properties of these two proposed alloys are investigated systematically. The proposed P6222-Si2Ge and P6222-SiGe2 have a hexagonal symmetry structure, and the phonon dispersion spectra and elastic constants indicate that these two alloys are dynamically and mechanically stable at ambient pressure. The elastic anisotropy properties of P6222-Si2Ge and P6222-SiGe2 are examined elaborately by illustrating the surface constructions of Young’s modulus, the contour surfaces of shear modulus, and the directional dependence of Poisson’s ratio; the differences with their corresponding group 14 element allotropes P6222-Si3 and P6222-Ge3 are also discussed and compared. Moreover, the Debye temperature and sound velocities are analyzed to study the thermodynamic properties of the proposed P6222-Si2Ge and P6222-SiGe2.
The role of ultraviolet photons in circumstellar astrochemistry
Authors: Millar T. J.
Published: November 2020

Stars with masses between 1 and 8 solar masses (M⊙) lose large amounts of material in the form of gas and dust in the late stages of stellar evolution, during their Asymptotic Giant Branch (AGB) phase. Such stars supply up to 35% of the dust in the interstellar medium and thus contribute to the material out of which our solar system formed. In addition, the circumstellar envelopes of these stars are sites of complex organic chemistry with over 80 molecules detected in them. We show that internal ultraviolet photons, either emitted by the star itself or from a close-in, orbiting companion, can significantly alter the chemistry that occurs in the envelopes particularly if the envelope is clumpy in nature. At least for the cases explored here, we find that in the presence of a stellar companion, such as a white dwarf star, the high flux of UV photons destroys H2O in the inner regions of carbon-rich AGB stars to levels below those observed and produces species such as C+ deep in the envelope in contrast to the expectations of traditional descriptions of circumstellar chemistry.
Flexible planar micro-supercapacitors based on carbon nanotubes
Authors: Cheng Wen-xiang , Jiang Tong-tong , Hu Hai-bo
Published: November 2020

The boom in ultra-thin electronic devices and the growing need for humanization greatly facilitated the development of wearable flexible micro-devices. But the technology to deposit electrode material on flexible substrate is still in its infancy. Herein, the flexible symmetric micro-supercapacitors made of carbon nanotubes (CNTs) on commercial printing paper as electrode materials were fabricated by combining tetrahedral preparator auxiliary coating method and laser-cutting interdigital configuration technique on a large scale. The electrochemical performance of the obtained micro-supercapacitors can be controlled and tuned by simple choosing different models of tetrahedral preparatory to obtain CNTs film of different thicknesses. As expected, the micro-supercapacitor based on CNTs film can deliver an areal capacitance up to 4.56 mF/cm2 at current of 0.02 mA. Even if, micro-supercapacitor undergoes continuous 10000 cycles, the performance of device can still remain nearly 100%. The as-demonstrated tetrahedral preparator auxiliary coating method and laser-cutting interdigital configuration technique provide new perspective for preparing microelectronics in an economical way. The paper electrode appended by CNTs achieves steerable areal capacitance, showing broad application prospect in fabricating asymmetric micro-supercapacitor with flexible planar configurations in the future.
Electron momentum spectroscopy study on inner orbitals of methyl iodide
Authors: Zhao Min-fu , Niu Shan-shan , Tian Qi-guo , Yang Jing , Shan Xu , Chen Xiang-jun
Published: November 2020

The binding energy spectrum and electron momentum profiles of the inner orbitals of methyl iodide have been measured using an electron momentum spectrometer at the impact energy of 1200 eV plus binding energy. Two peaks in the binding energy spectrum, arising from the spin-orbit splitting, are observed and the corresponding electron momentum profiles are obtained. Relativistic density functional calculations are performed to elucidate the experimental electron momentum profiles of two spin-orbit splitting components, showing agreement with each other except for the intensity in low momentum region. The measured high intensity in the low momentum region can be further explained by the distorted wave calculation.
Experimental investigation of a pitch-oscillating wind turbine airfoil with vortex generators
Authors: Li Shuang , Zhang Lei , Xu Jin , Yang Ke , Song Juanjuan , Guo Guangxing
Published: November 2020

The inflow shear and turbulence, tilt or yaw misalignment, and tower passage lead to dynamic stall on turbine blades. The effects of vortex generators (VGs) on the aerodynamic performance of a typical wind turbine airfoil, namely, DU91-W2-250, are measured under the background that VGs are gradually and widely installed for energy improvement. The experiment is carried out in a wind tunnel at the Reynolds number of 3×105. The oscillation of the testing model is driven by a servo motor, and the aerodynamic performance is measured using an ESP-64 scanner. The flow separation is visualized with tufts. The obtained results show that the installation of the VGs could effectively control both static stall and dynamic stall of the airfoil because VGs cause a lower pressure region on the airfoil suction surface near the leading edge and a pressure plateau that appears later than in the smooth airfoil. Meanwhile, the VGs could effectively increase the adverse pressure gradient and lead to an early transition to delay the flow separation before stall and force the flow field in the turbulence state. It is also found that the VGs could reduce the pressure fluctuations caused by the turbulence of the boundary layer during dynamic stall. Furthermore, the VGs are also found to be useful in suppressing the span-wise movement of vortices. However, the VGs could not improve the aerodynamic performance in the deep stall region under none of the static and dynamic conditions.
Self-consistent theory of the Darrieus–Landau and Rayleigh–Taylor instabilities with self-generated magnetic fields
Authors: García-Rubio F. , Betti R. , Sanz J. , Aluie H.
Published: November 2020

The Rayleigh–Taylor (RT) and Darrieus–Landau (DL) instabilities are studied in an inertial confinement fusion context within the framework of small critical-to-shell density ratio DR and weak acceleration regime, i.e., large Froude number Fr. The quasi-isobaric analysis in Sanz et al. [Phys. Plasmas 13, 102702 (2006)] is completed with the inclusion of non-isobaric and self-generated magnetic-field effects. The analysis is restricted to perturbation wavelengths k−1 larger than the conduction length scale at the ablation front, yet its validity ranges from wavelengths shorter and larger than the conduction layer width (distance between the ablation front and the critical surface). The use of a sharp boundary model leads to a single analytical expression of the dispersion relation encompassing both instabilities. The two new effects come into play by modifying the perturbed mass and momentum fluxes at the ablation front. The momentum flux (perturbed pressure at the spike) is the predominant stabilizing mechanism in the RT instability (overpressure) and the driving mechanism in the DL instability (underpressure). The non-isobaric effects notably modify the scaling laws in the DL limit, leading to an underpressure scaling as ∼k−11/15 rather than ∼k−2/5 obtained in the quasi-isobaric model. The magnetic fields are generated due to misalignment between pressure and density gradients (Biermann battery effect). They affect the hydrodynamics by bending the heat flux lines. Within the framework of this paper, they enhance ablation, resulting in a stabilizing effect that peaks for perturbation wavelengths comparable to the conduction layer width. The combination of parameters DRFr2/3 defines the region of predominance of each instability in the dispersion relation. It is proven that the DL region falls outside of the parameter range in inertial confinement fusion.
Tolerogenic nanoparticles suppress central nervous system inflammation
Authors: Kenison Jessica E. , Jhaveri Aditi , Li Zhaorong , Khadse Nikita , Tjon Emily , Tezza Sara , Nowakowska Dominika , Plasencia Agustin , Stanton Vincent P. , Sherr David H. , Quintana Francisco J.
Published: November 2020

Significance

Current treatments for autoimmune diseases rely on nonspecific immunosuppression, risking important complications and limiting the long-term use of these approaches for the treatment of chronic human autoimmunity. Thus, there is an unmet need for therapeutic approaches to reestablish immune tolerance in autoimmune disorders in an antigen-specific manner. Here, we describe a nanoliposome (NLP)-based platform for the induction of antigen-specific tolerance via the modulation of signaling by the aryl hydrocarbon receptor. These NLPs suppress disease pathology and pathogenic autoimmunity in preclinical models of multiple sclerosis, providing a candidate antigen-specific therapeutic approach for the management of autoimmune disorders.
Anthropomorphic metaphors in wine discourse, with special reference to Japanese wine manga
Authors: Normand-Marconnet Nadine , Jones Jason Christopher
Published: November 2020

Wine discourse has been readily found in the forms of wine tasting notes, reviews, advertisements, poetry, and classical literature. The popularity of Japanese wine manga, however, introduces a new venue for wine discourse and vector along which academic analysis can be conducted. In this paper, we seek to expand upon prior research on wine semantics and wine discourse by applying the framework of Cultural Linguistics to the subgenre of wine manga. Based on an original, Japanese-French bilingual corpus developed from the graphic novelsSommelierandKami no Shizuku – each an epoch-making work, highly didactic in nature – our analysis focuses on the conceptual metaphorwine is a person. Results illustrate the Japanese authors’ contribution to the figurative language used in wine discourse. In other words, in Japan just as in France, wine is a person, and there is a shared cultural understanding of wine, or traits therein, being the embodiment of the human.
Äiwoo wâtu and the typology of comparatives
Authors: Næss Åshild
Published: November 2020

This paper examines a comparative construction in the Oceanic language Äiwoo and argues that it differs from those known
in the typological literature on comparatives on two counts. It is similar to a so-called ‘exceed’ comparative in involving a
morpheme meaning ‘go far’; but unlike canonical exceed comparatives, the construction is intransitive, and the standard of
comparison is expressed as an oblique. Moreover, the standard is indicated not only by this oblique phrase but also by a directional marker
on the verb, in an extension of the frequent use of directionals in Äiwoo to indicate peripheral participants. This construction thus, on
the one hand, expands the established typology of comparative constructions; and on the other, shows that the use of directional morphemes
to indicate peripheral participants, otherwise attested e.g. for recipients of give verbs, may extend to the standard in
comparative constructions, pointing to an avenue for further typological exploration.
Limited rejuvenation of aged hematopoietic stem cells in young bone marrow niche
Authors: Kuribayashi Wakako , Oshima Motohiko , Itokawa Naoki , Koide Shuhei , Nakajima-Takagi Yaeko , Yamashita Masayuki , Yamazaki Satoshi , Rahmutulla Bahityar , Miura Fumihito , Ito Takashi , Kaneda Atsushi , Iwama Atsushi
Published: November 2020

Hematopoietic stem cells (HSCs) exhibit functional alterations, such as reduced regenerative capacity and myeloid-biased differentiation, with age. The HSC niche, which is essential for the maintenance of HSCs, also undergoes marked changes with aging. However, it has been technically challenging to directly evaluate the contribution of niche aging to age-associated HSC alterations without niche-damaging myeloablation in HSC transplantation assays. We herein transplanted an excess of aged HSCs into young mice without preconditioning. Although aged HSCs successfully engrafted in the intact young bone marrow niche, they poorly regenerated downstream progenitors and exhibited persistent myeloid-biased differentiation, resulting in no significant functional rejuvenation. Transcriptome and methylome analyses revealed that the young niche largely restored the transcriptional profile of aged HSCs, but not their DNA methylation profiles. Therefore, the restoration of the young niche is insufficient for rejuvenating HSC functions, highlighting a key role for age-associated cell-intrinsic defects in HSC aging.
Vi-specific serological correlates of protection for typhoid fever
Authors: Jin Celina , Hill Jennifer , Gunn Bronwyn M. , Yu Wen-Han , Dahora Lindsay C. , Jones Elizabeth , Johnson Mari , Gibani Malick M. , Spreng Rachel L. , Alam S. Munir , Nebykova Anna , Juel Helene B. , Dennison S. Moses , Seaton Kelly E. , Fallon Jonathan K. , Tomaras Georgia D. , Alter Galit , Pollard Andrew J.
Published: November 2020

Typhoid Vi vaccines have been shown to be efficacious in children living in endemic regions; however, a widely accepted correlate of protection remains to be established. We applied a systems serology approach to identify Vi-specific serological correlates of protection using samples obtained from participants enrolled in an experimental controlled human infection study. Participants were vaccinated with Vi-tetanus toxoid conjugate (Vi-TT) or unconjugated Vi-polysaccharide (Vi-PS) vaccines and were subsequently challenged with Salmonella Typhi bacteria. Multivariate analyses identified distinct protective signatures for Vi-TT and Vi-PS vaccines in addition to shared features that predicted protection across both groups. Vi IgA quantity and avidity correlated with protection from S. Typhi infection, whereas higher fold increases in Vi IgG responses were associated with reduced disease severity. Targeted antibody-mediated functional responses, particularly neutrophil phagocytosis, were also identified as important components of the protective signature. These humoral markers could be used to evaluate and develop efficacious Vi-conjugate vaccines and assist with accelerating vaccine availability to typhoid-endemic regions.
Mechanisms of laser energy absorption and melting behavior during selective laser melting of titanium-matrix composite: role of ceramic addition
Authors: Ge Qing , Gu Dongdong , Dai Donghua , Ma Chenglong , Sun Yixuan , Shi Xinyu , Li Yanze , Zhang Hongmei , Chen Hongyu
Published: November 2020

The laser energy absorption and melting behavior of ceramic reinforced metal matrix composites during selective laser melting (SLM) additive manufacturing are vital for the subsequent metallurgical behavior. In this study, the mesoscopic simulation was proposed to investigate the influence of ceramic addition on the laser energy absorption and powder melting behaviors during SLM of TiC/Ti6Al4V composites. As the addition of TiC particles increased from 0 wt.% to 5 wt.%, the packing density of composite powder increased from 2.357 g cm−3 to 2.588 g cm−3, while the hall velocity decreased from 36.00 s to 73.14 s, indicating the powder flowability decreased with the ceramic addition. Meanwhile, the number of laser-powder interactions increased from 1.267 × 106 to 1.626 × 106, thereby enhancing the laser multiple reflection phenomenon in the powder bed. The concentrated irradiance distribution on the metal powder was dispersed into the surrounding powder. The average irradiance intensity on TiC particles was continuously improved, which increased the overall laser absorptivity from 0.655 to 0.72, yielding an elevated maximum operating temperature within the molten pool from 3501 K to 3668 K. However, with the excessive addition of ceramics (5 wt.%), balls and trapped unmelted particles deteriorated the surface morphology of the melted track. It can be attributed to the high required energy for complete melted TiC and the elevated difficulty of completely wetting unmelted particles. These results provided the physical understanding of high-quality and defect-free components of SLM processed composite materials.
Two-photon interference: the Hong–Ou–Mandel effect
Authors: Bouchard Frédéric , Sit Alicia , Zhang Yingwen , Fickler Robert , Miatto Filippo M , Yao Yuan , Sciarrino Fabio , Karimi Ebrahim
Published: November 2020

Nearly 30 years ago, two-photon interference was observed, marking the beginning of a new quantum era. Indeed, two-photon interference has no classical analogue, giving it a distinct advantage for a range of applications. The peculiarities of quantum physics may now be used to our advantage to outperform classical computations, securely communicate information, simulate highly complex physical systems and increase the sensitivity of precise measurements. This separation from classical to quantum physics has motivated physicists to study two-particle interference for both fermionic and bosonic quantum objects. So far, two-particle interference has been observed with massive particles, among others, such as electrons and atoms, in addition to plasmons, demonstrating the extent of this effect to larger and more complex quantum systems. A wide array of novel applications to this quantum effect is to be expected in the future. This review will thus cover the progress and applications of two-photon (two-particle) interference over the last three decades.
Solitary wave solutions of the 2+1 and 3+1 dimensional nonlinear Dirac equation constrained to planar and space curves
Authors: Cooper Fred , Khare Avinash , Saxena Avadh
Published: November 2020

We study the effect of curvature and torsion on the solitons of the nonlinear Dirac equation considered on planar and space curves. Since the spin connection is zero for the curves considered here, the arc variable provides a natural setting to understand the role of curvature. We obtain for various curves in two and three dimensions the transformation of the Dirac equation to the 1 + 1 dimensional flat space Dirac equation written in terms of the arc length. Depending on the curvature, the soliton profile either narrows or expands. Our results may be applicable to yet-to-be-synthesized curved quasi-one dimensional Bose condensates.
Study of an acousto-optic Q-switched double pulse output Pr:YLF all solid-state laser
Authors: Li Yang , Jin Long , Dai Weicheng , Li Shutao , Dong Yuan , Jin Guangyong
Published: November 2020

This paper proposes a blue LD pumping Pr:YLF crystal acousto-optic Q-switched double pulse laser with 639 nm red light output. The output principle of the Pr:YLF double pulse laser is demonstrated, and a four level differential rate equation model is established to describe the distribution of the double pulse sequence at a high repetition frequency. When the laser repetition frequency is 10 kHz, the double step signal generator, as the modulator of the acousto-optic Q-switching, turns on the Q-switching twice in one pumping period, and obtains the maximum output power of 144 mW, pulse energy of 7.1μJ and the output of visible light double pulse with the pulse interval of 20 μs.
Information transmission based on a Fourier transform and ascending coding temporal ghost imaging algorithm
Authors: Hualong Ye , Leihong Zhang , Jian Chen , Kaimin Wang , Dawei Zhang , Songlin Zhuang
Published: November 2020

In this paper, based on the specific analysis of a temporal ghost imaging (TGI) algorithm, image coding transmission is realized by combining the compression characteristics of a Fourier transform, the convenient control and management function of ascending coding (AC) and the precise transmission function of TGI. AC, as a kind of sorting coding, has the characteristics of fast speed, high precision and wide application range. This paper analyzes noise attack, information, bit error rate (BER) and similarity, etc. Verified by simulation experiment, this algorithm can improve the compressibility of the encoded image, improve the difficulty of decoding by an attacker, reduce the BER in the process of image coding transmission, enhance the ability of anti-interference, realize accurate image coding transmission and solve the problems of low accuracy and low security of image transmission reconstruction at present.
Brownian motion and thermophoresis effects on unsteady stagnation point flow of Eyring–Powell nanofluid: a Galerkin approach
Authors: Khan Z H , Usman M , Zubair T , Hamid M , Haq R U
Published: November 2020

This article concerns the analysis of an unsteady stagnation point flow of Eyring–Powell nanofluid over a stretching sheet. The influence of thermophoresis and Brownian motion is also considered in transport equations. The nonlinear ODE set is obtained from the governing nonlinear equations via suitable transformations. The numerical experiments are performed using the Galerkin scheme. A tabular form comparison analysis of outcomes attained via the Galerkin approach and numerical scheme (RK-4) is available to show the credibility of the Galerkin method. The numerical exploration is carried out for various governing parameters, namely, Brownian motion, steadiness, thermophoresis, stretching ratio, velocity slip, concentration slip, thermal slip, and fluid parameters, and Hartmann, Prandtl and Schmidt numbers. The velocity of fluid enhances with an increase in fluid and magnetic parameters for the case of opposing, but the behavior is reversed for assisting cases. The Brownian motion and thermophoresis parameters cause an increase in temperature for both cases (assisting and opposing). The Brownian motion parameter provides a drop-in concentration while an increase is noticed for the thermophoresis parameter. All the outcomes and the behavior of emerging parameters are illustrated graphically. The comparison analysis and graphical plots endorse the appropriateness of the Galerkin method. It is concluded that said method could be extended to other problems of a complex nature.
Terahertz emission from nonlinear interaction of laser beat wave with nanoparticles
Authors: Varshney Prateek , Gopal Krishna , Upadhyay Ajit
Published: November 2020

Terahertz radiation is investigated using nonlinear interaction of a laser beat wave with a density-modulated medium of graphite nanoparticles. A beam-decentering parameter, b, is used to modify the polarizing field’s profile to produce different-shaped laser pulse envelopes, e.g. Gaussian, top head, ring-shaped and cosh-Gaussian. The normal vectors corresponding to the basal planes of graphite nanoparticles are considered to be aligned parallel and perpendicular to the polarization of the propagating laser pulse. The electronic cloud of the graphite nanoparticles acquires a nonlinear oscillatory velocity under the influence of a nonlinear force that produces a strong nonlinear current at the beat-wave frequency

(

ω
T

=

ω
1

−

ω
2

)

. The strong nonlinear current allows the emission of radiation in the terahertz frequency regime. The terahertz radiation intensifies and attains a peak value when the laser beat-wave frequency (

ω
T

) equals the plasmon frequency

ω
p

of the nanoparticles. The terahertz radiation’s amplitude is enhanced by up to the fourth order of magnitude in the case of a cosh-Gaussian laser pulse, when the beam-decentering parameter,
b, equals 5. The present numerical results reveal that by changing the shape of a laser pulse and the properties of nanoparticles, one can control and tune the THz emission.
Self-induced transparency in a system of resonant–quasiresonant transitions
Authors: Sazonov S V , Ustinov N V
Published: November 2020

The effect of self-induced transparency is investigated for a three-level system with a V-scheme of the allowed transitions in the case where one of the transitions is resonant while another one is quasiresonant. The generalized system of the wave and material equations for the resonant transition, taking into account the presence of a quasiresonant transition, is derived. This system is integrable, and its soliton solutions are investigated. It is shown that quasiresonant transition has an influence on the profile of the optical soliton and leads to its phase modulation. The conditions under which the propagation of the soliton is followed by the full inversion of the populations of quantum levels of the resonant transition are established.
A polarization study of the supernova remnant CTB 80
Authors: Li Xiang-Hua , Sun Xiao-Hui , Reich Wolfgang , Gao Xu-Yang
Published: November 2020

We present a radio polarization study of the supernova remnant CTB 80 based on images at 1420 MHz from the Canadian Galactic Plane Survey, at 2695 MHz from the Effelsberg survey of the Galactic plane and at 4800 MHz from the Sino-German λ6 cm polarization survey of the Galactic plane. We obtained a rotation measure (RM) map using polarization angles at 2695 MHz and 4800 MHz as the polarization percentages are similar at these two frequencies. RM exhibits a transition from positive values to negative values along one of the shells hosting the pulsar PSR B1951+32 and its pulsar wind nebula. The reason for the change in sign remains unclear. We identified a partial shell structure, which is bright in polarized intensity but weak in total intensity. This structure could be part of CTB 80 or part of a new supernova remnant unrelated to CTB 80.
Axial force radiometer for primary standard laser power measurements using photon momentum
Authors: Williams Paul A , Rogers Kyle A , Hadler Joshua A , Artusio-Glimpse Alexandra B , Lehman John H
Published: November 2020

We have demonstrated operation of a new photon momentum radiometer for measuring laser power levels above 1 kW by use of radiation pressure. The ‘axial’ design allows the input and output laser beams to remain collinear and the force sensing can be carried out with any analytical balance having a vertical sensing direction and sufficient readability (sensitivity). The design also provides for a parasitic fast photodiode power measurement that is calibrated in situ by the slower radiation pressure-based power measurement. This permits a short-time-constant measurement limited primarily by the photodiode bandwidth, rather than the response time of the force balance. Uncertainty contributions yield a relative expanded uncertainty of 2.1% for (1–2) kW and 1.2% above 2 kW (for laboratory environmental conditions). We perform a direct comparison between this new power meter and the existing primary standard radiation pressure power meter. We find the two techniques agree with an average inequivalence of 0.12% for continuous wave (CW) optical powers from (1–10.8) kW. This disagreement is well-explained by the quadrature-summed uncertainties of the two techniques.
Naturalistic spatiotemporal modulation of epiretinal stimulation increases the response persistence of retinal ganglion cell
Authors: Chenais Naïg Aurelia Ludmilla , Airaghi Leccardi Marta Jole Ildelfonsa , Ghezzi Diego
Published: November 2020

Objective. Retinal stimulation in blind patients evokes the sensation of discrete points of light called phosphenes, which allows them to perform visually guided tasks, such as orientation, navigation, object recognition, object manipulation and reading. However, the clinical benefit of artificial vision in profoundly blind patients is still tenuous, as several engineering and biophysical obstacles keep it far away from natural perception. The relative preservation of the inner retinal neurons in hereditary degenerative retinal diseases, such as retinitis pigmentosa, supports artificial vision through the network-mediated stimulation of retinal ganglion cells (RGCs). However, the response of RGCs to repeated electrical stimulation rapidly declines, primarily because of the intrinsic desensitisation of their excitatory network. In patients, upon repetitive stimulation, phosphenes fade out in less than half of a second, which drastically limits the understanding of the percept. Approach. A more naturalistic stimulation strategy, based on spatiotemporal modulation of electric pulses, could overcome the desensitisation of RGCs. To investigate this hypothesis, we performed network-mediated epiretinal stimulations paired to electrophysiological recordings in retinas explanted from both male and female retinal degeneration 10 mice. Main results. The results showed that the spatial and temporal modulation of the network-mediated epiretinal stimulation prolonged the persistence of the RGC’s response from 400 ms up to 4.2 s. Significance. A time-varied, non-stationary and interrupted stimulation of the retinal network, mimicking involuntary microsaccades, might reduce the fading of the visual percept and improve the clinical efficacy of retinal implants.
Using convolutional neural networks to decode EEG-based functional brain network with different severity of acrophobia
Authors: Wang Qiaoxiu , Wang Hong , Hu Fo , Hua Chengcheng , Wang Dangxiao
Published: November 2020

Objective. The prevalence of acrophobia is high, especially with the rise of many high-rise buildings. In the recent few years, researchers have begun to analyze acrophobia from the neuroscience perspective, especially to improve the virtual reality exposure therapy (VRET). Electroencephalographic (EEG) is an informative neuroimaging technique, but it is rarely used for acrophobia. The purpose of this study is to evaluate the effectiveness of using EEGs to identify the degree of acrophobia objectively. Approach. EEG data were collected by virtual reality (VR) exposure experiments. We classified all subjects’ degrees of acrophobia into three categories, where their questionnaire scores and behavior data showed significant differences. Using synchronization likelihood, we computed the functional connectivity between each pair of channels and then obtained complex networks named functional brain networks (FBNs). Basic topological features and community structure features were extracted from the FBNs. Statistical results demonstrated that FBN features can be used to distinguish different groups of subjects. We trained machine learning (ML) algorithms with FBN features as inputs and trained convolutional neural networks (CNNs) with FBNs directly as inputs. Main results. It turns out that using FBN to identify the severity of acrophobia is feasible. For ML algorithms, the community structure features of some cerebral cortex regions outperform typical topological features of the whole brain, in terms of classification accuracy. The performances of CNN algorithms are better than ML algorithms. The CNN with ResNet performs the best (accuracy reached 98.46 ± 0.42%). Significance. These observations indicate that community structures of certain cerebral cortex regions could be used to identify the degree of acrophobia. The proposed CNN framework can provide objective feedback, which could help build closed-loop VRET portable systems.
Design of quasi-axisymmetric stellarators with varying-thickness permanent magnets based on Fourier and surface magnetic charges method
Authors: Xu G.S. , Lu Z.Y. , Chen D.H. , Chen L. , Zhang X.Y. , Wu X.Q. , Ye M.Y. , Wan B.N.
Published: November 2020

To obtain engineering-feasible designs of stellarators with permanent magnets and simplified coils, a new algorithm has been developed based on Fourier decomposition and surface magnetic charges method. The strong toroidal fields in a quasi-axisymmetric stellarator are still generated by coils. The permanent magnets are designed to compensate the normal magnetic field B

n
on the plasma surface ∂P created by the coils and plasma. The normal magnetic fields created by the permanent magnets B
pmn are calculated as the difference between the magnetic fields created by the surface magnetic charges on the inner surface ∂D and the outer surface ∂D

h
of the magnets. The Fourier coefficients of the magnet thickness function

h

θ
,
ϕ

are computed through matrix division operation based on the least square principle with dominant Fourier components selected through 2D Fourier transformation of B
pmn. The residual uncompensated B

n
is minimized through iteration to progressively optimize the thickness function. This new algorithm has been successfully applied to design the permanent magnets of an l = 2 quasi-axisymmetric stellarator with background magnetic field created by 12 identical circular planar coils for demonstrations. High accuracy has been achieved, allowing for a flux-surface-averaged residual B

n
relative to the total field

B

n

/
B

∼
1.3
×
1

0

−
5

and a maximum residual B

n
of less than 2 Gs for ∼1 T total field. This new design has some advantages in engineering implementations: all permanent magnet pieces have the same remanence B
r; only one single layer of magnets are mounted perpendicular to the winding surface; the magnets can be easily inserted into the cells of a gridded frame attached to the winding surface and fixed with springs from the back, which greatly simplifies the manufacture, assembly and maintenance of the magnets, and thus facilitates precision control and cost reduction.
Simplified selection of optimal shell in shape of translational surface
Authors: Tupikova E , Korshunova N , Bykova G
Published: November 2020

The translational shells are arised by moving generatrix line along directrix line. Four shells of similar overall size and rising height are modelled in the present job, each generatrix coincide with directrix, the symmetric square plane is considered. The surface types are: surface of translation of circle along circle, catenary along catenary, sinus along sinus and ellipse along ellipse. The behaviour under equally distributed load like self-weight of 4 types of shells is considered, equally distributed load case while supporting on four corner points is considered. The solution is obtained by means of finite element analysis. The ratio of bending and membrane stresses is of interest as the criterion of optimal operation under load. The equalent von Mises stresses for abstract material with characteristics of reinforced concrete are obtained to reveal the most dangerous zones and evaluate the overall stress distribution. The study is of interest in view of perspectives to introduction into practise of structure elements of such shape.