bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of an endothermic electrode for electroporation-based therapies: A simulation study
Authors: Zhao Yajun , Davalos Rafael V.
Published: October 2020

Cell death mediated by non-thermal mechanisms is an essential characteristic of irreversible electroporation for tumor ablation. However, needle electrodes inherently promote thermal damage immediately adjacent to the electrode/tissue interface, especially in cases when intensive pulsed electric fields are applied to get a large ablation. In this study, we propose utilization of endothermic reactions in the core of clinically used needle electrodes to absorb the heat generated during electroporation, thereby accentuating the nonthermal aspect of irreversible electroporation. In this study, numerical models were developed to determine temperature profiles resulting from a typical irreversible electroporation (IRE) protocol in clinic using either conventional solid electrodes or hollow electrodes filled with NH4NO3 to facilitate an endothermic reaction in the electrode core. The results indicate that the endothermic electrodes can reduce the temperature rise and thermal damage during IRE treatment.
Performance and security of 5 GHz repetition rate polarization-based quantum key distribution
Authors: Grünenfelder Fadri , Boaron Alberto , Rusca Davide , Martin Anthony , Zbinden Hugo
Published: October 2020

We present and characterize a source for a 5 GHz clocked polarization-based simplified BB84 protocol. Secret keys are distributed over 151.5 km of standard telecom fiber at a rate of 54.5 kbps. Potentially, an increased clock frequency of the experiment introduces correlations between succeeding pulses. We discuss the impact of these correlations and propose measurements to estimate the relevant parameters.
Consistent probe spacing in multi-probe STM experiments
Authors: Onoda Jo , Vick Doug , Salomons Mark , Wolkow Robert , Pitters Jason
Published: October 2020

Multi-probe scanning tunneling microscopy can play a role in various electrical measurements and characterization of nanoscale objects. The consistent close placement of multiple probes relies on very sharp apexes with no other interfering materials along the shank of the tip. Electrochemically etched tips can prepare very sharp apex tips; however, other asperities on the shank can cause interference and limit the close positioning of multiple tips to beyond the measured radii. Gallium focused ion beam (FIB) milling is used to remove any interfering material and allow closely spaced tips with a consistent yield. The tip apex radius is evaluated with field ion microscopy, and the probe spacing is evaluated with STM on hydrogen terminated silicon surfaces. FIB prepared tips can consistently achieve the measured probe to probe spacing distances of 25 nm–50 nm.
Magnetic flux quantum periodicity of the frequency of the on-chip detectable electromagnetic radiation from superconducting flux-flow-oscillators
Authors: Chesca Boris , John Daniel , Gaifullin Marat , Cox Jonathan , Murphy Aidan , Savel'ev Sergey , Mellor Christopher J.
Published: October 2020

Superconducting flux-flow-oscillators (FFOs) based on unidirectional flow of magnetic vortices in a single-long Josephson junction (JJ) and operating at 4.2 K are key elements of sub-terahertz integrated-receivers used in radio-astronomy and atmospheric science. Here, we report on the development of sub-terahertz FFOs based on parallel JJ-arrays made of YBa2Cu3O7−δ thin films. Sharp multiple flux-flow resonances were observed in the temperature range 77–89 K in asymmetric JJ-arrays, suggesting that they can operate as a narrow-band FFO in sub-terahertz integrated-receivers at more practical temperatures than 4.2 K. We detected electromagnetic radiation (EM) emitted by symmetric JJ-arrays in the range of 30–45 K using on-chip build superconducting detectors based on single JJs. For both asymmetric and symmetric JJ-arrays, the frequency f of the emitted radiation could be tuned continuously by an applied magnetic flux Φ with a one-flux-quantum Φ0 periodicity. Remarkably, since f can be tuned continuously, there are no gaps in the frequency range of the emitted EM. The fundamental Φ0-periodicity of f(Φ) is similar in nature to a SQUID's voltage response V(Φ) and, consequently, using high-performance magnetic flux-to-field conversion and readout techniques, a sensitive field-to-frequency magnetometer can be developed. Incorporated into non-accessible micro/nanostructures as a magnetic sensor, it would allow precise measurements of magnetic-fields from a distance, without the need to measure it locally as the radiation is detected remotely.
Hydrodynamics across a fluctuating interface
Authors: Smith Edward R. , Braga Carlos
Published: October 2020

Understanding what happens inside the rippling and dancing surface of a liquid remains one of the great challenges of fluid dynamics. Using molecular dynamics, we can pick apart the interface structure and understand surface tension. In this work, we derive an exact mechanical formulation of hydrodynamics for a liquid–vapor interface using a control volume, which moves with the surface. This mathematical framework provides the local definition of hydrodynamic fluxes at any point on the surface. These are represented not only by the flux of molecules and intermolecular interactions acting across the surface but also as a result of the instantaneous local curvature and movement of the surface itself. By explicitly including the surface dynamics in the equations of motion, we demonstrate an exact balance between kinetic and configurational pressure normal to the surface. The hydrodynamic analysis makes no assumptions regarding the probability distribution function, so it is valid for any system arbitrarily far from thermodynamic equilibrium. The presented equations provide a theoretical basis for the study of time-evolving interface phenomena, such as bubble nucleation, droplet dynamics, and liquid–vapor instabilities.
Numerical analysis of nonlinear thermal stress flow between concentric elliptical cylinders
Authors: Rafieenasab Sepehr , Roohi Ehsan , Teymourtash Alireza
Published: October 2020

The present study numerically investigates nonlinear thermal stress in a rarefied gas flow between two coaxial elliptic cylinders with a hot outer wall. Monatomic argon is considered, and isothermal boundary conditions are implemented on the walls. Three different numerical methods are used to solve this problem, i.e., first, the direct simulation Monte Carlo (DSMC) method is used and validated against the numerical solution of the Boltzmann equation available in the literature. The results of the DSMC algorithm are compared with the results of the discrete unified gas kinetic scheme and the continuum set of equations of slow non-isothermal flows, which includes nonlinear thermal stress terms compared to the Navier–Stokes equations. For the first time, the flow is examined in a wide range of Knudsen numbers in the slip regime from the Knudsen number (Kn) of Kn = 0.005 to Kn = 0.1. At a minimal Knudsen number, there is just one vortex due to the nonlinear thermal stress flow; however, as Kn increases, the velocity peak near the inner cylinder is replaced with another vortex, which is created due to the second-order thermal creep effects on the inner wall of the cylinder. We show that as Kn increases, the inner vortex increases in size, while the outer vortex shrinks. The mechanisms of the formation of both vortices are described in detail. Other flow characteristics, including walls’ velocity slip, shear stress, and vorticity, are discussed.
Marcus–Hush–Chidsey kinetics at electrode–electrolyte interfaces
Authors: Kurchin Rachel , Viswanathan Venkatasubramanian
Published: October 2020

Electrochemical kinetics at electrode–electrolyte interfaces limit the performance of devices including fuel cells and batteries. While the importance of moving beyond Butler–Volmer kinetics and incorporating the effect of electronic density of states of the electrode has been recognized, a unified framework that incorporates these aspects directly into electrochemical performance models is still lacking. In this work, we explicitly account for the density functional theory-calculated density of states numerically in calculating electrochemical reaction rates for a variety of electrode–electrolyte interfaces. We first show the utility of this for two cases related to Li metal electrodeposition and stripping on a Li surface and a Cu surface (anode-free configuration). The deviation in reaction rates is minor for cases with flat densities of states such as Li, but is significant for Cu due to nondispersive d-bands creating large variation. Finally, we consider a semiconducting case of a solid-electrolyte interphase consisting of LiF and Li2CO3 and note the importance of the Fermi level at the interface pinned by the redox reaction occurring there. We identify the asymmetry in reaction rates as a function of discharge/charge naturally within this approach.
Enhancement of L-band optical absorption in strained epitaxial Ge on Si-on-quartz wafer: Toward extended Ge photodetectors
Authors: Noguchi Kyosuke , Nishimura Michiharu , Tsusaka Yoshiyuki , Matsui Junji , Ishikawa Yasuhiko
Published: October 2020

Enhanced optical absorption in the L band (1.565–1.625 μm) of optical communication is reported for a Ge epitaxial layer grown on a Si-on-quartz (SOQ) wafer toward an extended range Ge photodetector (PD) in Si photonics. Ge epitaxial layers are grown using ultrahigh vacuum chemical vapor deposition at 600 °C on three different wafers of bonded SOQ, bonded Si-on-sapphire (SOS), and ordinary bonded Si-on-insulator (SOI). In the Ge layer, depending on thermal expansion mismatch between the Ge layer and base substrate, different amounts of in-plane biaxial lattice strain are generated. X-ray diffraction shows that an enhanced tensile strain of 0.32 ± 0.02% is generated in Ge on SOQ, which is approximately two times higher than 0.17 ± 0.02% in Ge on SOI, whereas the strain in Ge on SOS shows a slightly compressive value of −0.06 ± 0.02%. Photoreflectance spectra for these Ge layers show a change in the direct bandgap energy in accordance with the strain. In particular, the direct bandgap energy reduces from 0.775 ± 0.003 eV for Ge on SOI to 0.747 ± 0.003 eV for strain-enhanced Ge on SOQ, being comparable to 0.74 eV for the standard III–V PD material of In0.53Ga0.47As on InP. Furthermore, enhanced optical absorption in the L band is realized for Ge on SOQ, as measured using free-space pin PDs. These results indicate that the operating wavelength range of Ge PD on SOQ extends from C (1.530–1.565 μm) to the L band.
Oxygenation state of hemoglobin defines dynamics of water molecules in its vicinity
Authors: Latypova Larisa , Barshtein Gregory , Puzenko Alexander , Poluektov Yuri , Anashkina Anastasia , Petrushanko Irina , Fenk Simone , Bogdanova Anna , Feldman Yuri
Published: October 2020

This study focuses on assessing the possible impact of changes in hemoglobin (Hb) oxygenation on the state of water in its hydration shell as it contributes to red blood cell deformability. Microwave Dielectric Spectroscopy (MDS) was used to monitor the changes in interactions between water molecules and Hb, the number of water molecules in the protein hydration shell, and the dynamics of pre-protein water in response to the transition of Hb from the tense (T) to the relaxed (R) state, and vice versa. Measurements were performed for Hb solutions of different concentrations (5 g/dl–30 g/dl) in phosphate-buffered saline buffer. Cole–Cole parameters of the main water relaxation peak in terms of interactions of water molecules (dipole–dipole/ionic dipole) during the oxygenation–deoxygenation cycle were used to analyze the obtained data. The water mobility—represented by α as a function of ln τ—differed dramatically between the R (oxygenated) state and the T (deoxygenated) state of Hb at physiologically relevant concentrations (30 g/dl–35 g/dl or 4.5 mM–5.5 mM). At these concentrations, oxygenated hemoglobin was characterized by substantially lower mobility of water in the hydration shell, measured as an increase in relaxation time, compared to deoxyhemoglobin. This change indicated an increase in red blood cell cytosolic viscosity when cells were oxygenated and a decrease in viscosity upon deoxygenation. Information provided by MDS on the intraerythrocytic water state of intact red blood cells reflects its interaction with all of the cytosolic components, making these measurements powerful predictors of the changes in the rheological properties of red blood cells, regardless of the cause.
Correlation of internal flow structure with heat transfer efficiency in turbulent Rayleigh–Bénard convection
Authors: Xu Ao , Chen Xin , Wang Feng , Xi Heng-Dong
Published: October 2020

To understand how internal flow structures manifest themselves in the global heat transfer, we study the correlation between different flow modes and the instantaneous Nusselt number (Nu) in a two-dimensional square Rayleigh–Bénard convection cell. High-resolution and long-time direct numerical simulations are carried out for Rayleigh numbers between 107 and 109 and a Prandtl number of 5.3. The investigated Nusselt numbers include the volume-averaged Nuvol, the wall-averaged Nuwall, the kinetic energy dissipation based Nukinetic, and the thermal energy dissipation based Nuthermal. The Fourier mode decomposition and proper orthogonal decomposition are adopted to extract the coherent flow structure. Our results show that the single-roll mode, the horizontally stacked double-roll mode, and the quadrupolar flow mode are more efficient for heat transfer on average. In contrast, the vertically stacked double-roll mode is inefficient for heat transfer on average. The volume-averaged Nuvol and the kinetic energy dissipation based Nukinetic can better reproduce the correlation of internal flow structures with heat transfer efficiency than that of the wall-averaged Nuwall and the thermal energy dissipation based Nuthermal, even though these four Nusselt numbers give consistent time-averaged mean values. The ensemble-averaged time trace of Nu during flow reversal shows that only the volume-averaged Nuvol can reproduce the overshoot phenomenon that is observed in the previous experimental study. Our results reveal that the proper choice of Nu is critical to obtain a meaningful interpretation.
Tri-gate GaN junction HEMT
Authors: Ma Yunwei , Xiao Ming , Du Zhonghao , Yan Xiaodong , Cheng Kai , Clavel Michael , Hudait Mantu K. , Kravchenko Ivan , Wang Han , Zhang Yuhao
Published: October 2020

This work presents a tri-gate GaN junction high-electron-mobility transistor (JHEMT) concept in which the p–n junction wraps around the AlGaN/GaN fins in the gate region. This tri-gate JHEMT differs from all existing GaN FinFETs and tri-gate HEMTs, as they employ a Schottky or a metal-insulator-semiconductor (MIS) gate stack. A tri-gate GaN JHEMT is fabricated using p-type NiO with the gate metal forming an Ohmic contact to NiO. The device shows minimal hysteresis and a subthreshold slope of 63 ± 2 mV/decade with an on-off current ratio of 108. Compared to the tri-gate MISHEMTs fabricated on the same wafer, the tri-gate JHEMTs exhibit higher threshold voltage (VTH) and achieve positive VTH without the need for additional AlGaN recess. In addition, this tri-gate JHEMT with a fin width of 60 nm achieves a breakdown voltage (BV) > 1500 V (defined at the drain current of 1 μA/mm at zero gate bias) and maintains the high BV with the fin length scaled down to 200 nm. In comparison, the tri-gate MISHEMTs with narrower and longer fins show punch-through at high voltages. Moreover, when compared to planar enhancement mode HEMTs, tri-gate JHEMTs show significantly lower channel sheet resistance in the gate region. These results illustrate a stronger channel depletion and electrostatic control in the junction tri-gate compared to the MIS tri-gate and suggest great promise of the tri-gate GaN JHEMTs for both high-voltage power and low-voltage power/digital applications.
Influence of electron irradiation and rapid thermal annealing on photoluminescence from GaAsNBi alloys
Authors: Pavelescu E.-M. , Ligor O. , Occena J. , Ticoş C. , Matei A. , Gavrilă R. L. , Yamane K. , Wakahara A. , Goldman R. S.
Published: October 2020

We have examined the influence of electron irradiation and rapid thermal annealing on photoluminescence emission from GaAsNBi alloys. Electron irradiation of a 1-eV compressively strained GaNAsBi-on-GaAs epilayer, grown by molecular beam epitaxy and subsequently rapidly thermally annealed, is found to induce much stronger photoluminescence than what is observed for an identical as-grown sample upon annealing. At the same time, annealing of the irradiated sample caused a negligible spectral blueshift and reduced alloy potential energy fluctuations. These irradiation-related phenomena occurred without a change in the alloy macroscopic composition as revealed by x-ray diffraction and are mainly related to the nitrogen incorporated into non-substitutional sites in the quaternary alloy.
Mechanical design of apertures and the infolding of pollen grain
Authors: Božič Anže , Šiber Antonio
Published: October 2020

Significance

Pollen carries male plant genetic material encapsulated in a hard protective shell containing flexible, soft regions—apertures. The mechanical design of the shell regulates how the pollen grain folds into itself upon dehydration, which often occurs once it becomes exposed to the environment. We investigate folding pathways of pollen grains by studying elastic deformations of inhomogeneous thin shells. Different pathways are governed by the interplay between the elastic properties of the hard and soft regions of the pollen shell and by the aperture shape, number, and size. We delineate regions of mechanical parameters of the pollen grain which lead to complete closure of all apertures, thus reducing water loss and presenting evolutionary viable solutions to the infolding problem.
Thermal capacities: system or process properties?
Authors: Anacleto Joaquim
Published: October 2020

We discuss the definitions of thermal capacities and make clear that these quantities are system properties. This clarification is pertinent since, in an initial approach to this topic, thermal capacities are defined by resorting to heat, which is not a system property, but a process property. Obtaining a system property from a process property is usually done by restricting its definition to particular processes, which is neither educationally attractive nor necessary. Furthermore, it is shown that dissipative work is as required as heat in defining a system property, but this fact is repeatedly ignored in the literature. For illustrative purposes, the formalism is then applied to a general process carried out by an ideal gas. Beyond scientific aspects, this work has a significant educational nature, as it may help dispel some misunderstandings related to the concepts covered herein.
Design and implementation of dual pressure variation chambers for bone conduction microphone
Authors: You Bo-Cheng , Lo Sung-Cheng , Chan Chun-Kai , Li Cheng-Syun , Ho Hsien-Lung , Chiu Shih-Chia , Hsieh Guan-Hong , Fang Weileun
Published: October 2020

This study presents a bone conduction microphone (BCM) to detect the variation of air pressure resulted from the skull vibration. The presented BCM consists of a commercial MEMS microphone, the sensing circuits, the bulk metal, the deformable polymer diaphragm, and two printed circuit board (PCB) covers. In this design, two chambers and a vibrating spring-mass structure are hermetic sealed by two PCB covers. As the spring-mass structure vibrates, the pressure of one chamber will increase and that of another will decrease. Thus, the vibration could introduce a higher pressure load as well as a larger sensing signal for the BCM. In application, the device with the dimensions of 3.5 × 2.65 × 1.48 mm3 is implemented. Measurements show the device has a sensitivity of −38.8 dBV, THD < 0.48% at 1 kHz with 1 g excitation, and ±5 dB bandwidth for 100 Hz∼6.7 kHz. Frequency responses of different samples show good repeatability. Furthermore, air leakage effect and crosstalk of the skull vibration sensing module have also been investigated in this paper. The results demonstrate the feasibility of the presented BCM.
Diamond-gold nanohybrids – an enhanced cathode material for field electron emitter applications
Authors: Sankaran Kamatchi Jothiramalingam , Kurian Joji , Sundaravel Balakrishnan , Nan Lin I- , Haenen Ken
Published: October 2020

This work aims to review the enhancement of electrical conductivity and field electron emission (FEE) properties of ultrananocrystalline diamond (UNCD) films as a function of gold ion implantation content. Au has been employed in UNCD films as an implanted species as well as an interlayer between diamond film and substrate. In the initial part of the review UNCD films are briefly introduced. The focus is on their FEE properties and multiple strategies employed for enhancing these properties using ion-implantation with the goal to obtain a better cathode material. A comparison of the characteristics of the UNCD films implanted with Au and other species after studying the modification of the microstructure and emission properties of the Au-implanted UNCD films is then provided. Subsequently, the use of a thin Au coating on silicon substrates covered by UNCD or hybrid granular structured diamond films is discussed. The Si diffusion through the Au-Si eutectic interface results in a SiC layer. This facilitates the nucleation of diamond clusters, thereby suppressing the development of the carbon layer which is amorphous and electrically resistive, resulting in improved FEE characteristics. Finally, in the third and final part, the combined effects of Au-ion implantation (including multi-energy Au ion implantation) and Au-interlayer is discussed. Based on the obtained results, the catalytic activity of gold for improving the electrical conductivity and the FEE properties of diamond films is highlighted.
Evolution to an anisotropic band structure caused by Sn doping in Bi1.995Sn0.005Te3 single crystals
Authors: Salawu Yusuff Adeyemi , Sasaki Minoru , Kulbachinskii Vladimir Anatol’evich , Ohnishi Akimasa , Kim Heon-Jung
Published: October 2020

Magnetotransport studies have established the existence of exotic electronic properties in materials of technological and fundamental interest. However, measurements of the Shubnikov–de Haas oscillations, intended to reveal information about Fermi surfaces (FSs), have mostly been carried out in magnetic fields perpendicular to the applied currents. Here, using magnetic fields not only perpendicular but also parallel to the applied currents in a given contact configuration, we investigated the anisotropic magnetotransport and the anisotropic FS properties of Bi2−x
Sn
x
Te3 (0 ⩽ x ⩽ 0.0075) and Bi2Se3. While the magnetotransport properties of Bi2Te3 and Bi2Se3 were nearly isotropic, Bi1.995Sn0.005Te3 exhibited quite anisotropic features. These observations are attributed to the nonparabolicity of the associated bands, which evolved to more anisotropic band structures with Sn concentration. This sensitivity of the band anisotropy was rather unexpected because only a small number of dopants are known to increase disorder levels in the degenerate region. Our approach, using two different magnetic field directions in the measurements of the Shubnikov–de Haas oscillations, is a simple and easily adoptable method for shedding more light on the FSs of functional materials.
Experimental demonstration of the plasma electron density diagnostics using the single-shot THz detection method
Authors: Kang Keekon , Lee Sihyeon , Jang Dogeun , Kim Jinju , Suk Hyyong
Published: October 2020

We report the first experimental demonstration of a novel plasma diagnostics method using the single-shot THz detection method. In this experiment, a broadband single THz pulse is generated by focusing two-color (400 nm and 800 nm in wavelength) laser pulses in air and the THz pulse is sent through an inductively-coupled plasma with a density of 1013–1014 cm−3 which is in the modern tokamak plasma density range. Phase shift of the THz pulse is measured by the single-shot THz detection method and the instant plasma density information is obtained from the phase shift. The result is compared with that of the existing THz time domain spectroscopy method and it is found that both results are in good agreement. It implies that the proposed method in this paper can provide a new plasma diagnostics tool which can be used for dynamically changing plasmas.
A systematic map of responses to climate impacts in urban Africa
Authors: Hunter NB , North MA , Roberts DC , Slotow R
Published: October 2020

Over time African cities and their residents have responded to climate impacts in increasingly creative ways, based on local knowledge and available resources. Overviews of adaptation policy, plans and actions have largely been lacking for Africa, particularly at the local, city level. We applied a systematic map to assess what the human responses to climate impacts are in African cities, noting the climate drivers of these actions, the range of responses, where they have taken place, and who the actors are. Standardized, pre-selected search terms were used to systematically search peer-reviewed and grey literature, using Web of Science, Scopus, and Google. Publications were screened based on pre-approved inclusion criteria, and actions described in included articles were coded using categories from key conceptual framing papers on climate change adaptation. Of 2 042 peer-reviewed and 60 grey-literature publications, 252 underwent full-text screening, with 121 included for coding. We recorded 1 504 actions, taking place in 41 cities from 21 African countries, in response to various climate drivers. Anticipatory and reactive actions were taken by actors, from individuals to international agencies, and we highlighted successful adaptations, those taking advantage of climate impacts, and maladaptive actions. Combinations of climatic and non-climatic stimuli induced adaptive responses, which were frequently based on local knowledge, and provided a base upon which government action could build. Residents of informal settlements had less adaptive capacity than those in formal settlements, and government action could build their resilience. Since development is affected by climate impacts, climate change information should be integrated into development programmes.
Advancing a transformative social contract for the environmental sciences: From public engagement to justice
Authors: Blue Gwendolyn , Davidson Debra
Published: October 2020

Taking as a starting point Jane Lubchenco’s call for a renewed social contract for environmental science, this paper advances a framework for science’s place in society in which justice is central. A social contract is a desired vision of social order that distributes rights, responsibilities, and obligations among political actors. The magnitude of global ecological change, our collective inability to address ecological crises, and populist challenges to science have renewed interest in debates about existing social contracts with science. While Lubchenco’s vision of a social contract focuses on practical ways to improve the engagement of scientists with decision-makers and citizens, we argue that to achieve the objectives laid out by Lubchenco, justice—encompassing representation, distribution, and recognition—must be at the core of science-society relations. A justice-centred social contract with science requires acknowledgement on the part of scientists, administrators, decision-makers, and citizens of the biases, inequalities and inequities contained within and advanced by academic institutions. Orienting science towards justice provides a starting point for a more diverse, inclusive, and equitable culture of publicly-funded research.
Reindeer use of low Arctic tundra correlates with landscape structure
Authors: Skarin Anna , Verdonen Mariana , Kumpula Timo , Macias-Fauria Marc , Alam Moudud , Kerby Jeffrey , Forbes Bruce C
Published: October 2020

Rapid climate change in Arctic regions is linked to the expansion of woody taxa (shrubification), and an increase in biomass as tundra becomes greener. Reindeer and caribou (Rangifer tarandus) are considered able to suppress vegetative greening through grazing and trampling. Quantifying reindeer use of different land cover types can help us understand their impact on the growth and recruitment of deciduous shrubs, many of which serve as fodder (e.g. Salix spp.), in favourable habitats, such as naturally denuded landslides in permafrost areas. Understanding the spatial distribution of reindeer pressure on vegetation is important to project future patterns of greening, albedo, snow capture, active layer development, and the overall resilience of tundra rangelands under ongoing climate change. Here we quantify reindeer habitat use within the low Arctic tundra zone of Yamal, West Siberia estimated from pellet-group counts, and also how active layer thickness (ALT) relates to reindeer use. Our results confirm intensive use by reindeer of terrain with high June-July time integrated normalised difference vegetation index, steeper slopes, ridges, upper slopes and valleys, and a preference for low erect shrub tundra. These sites also seem to have a shallower ALT compared to sites less used by reindeer, although we did not find any direct relationship between ALT and reindeer use. Low use of tall Salix habitats indicated that reindeer are unlikely to suppress the growth of already tall-erect woody taxa, while they exert maximum pressure in areas where shrubs are already low in stature, e.g. ridgetops. Reindeer ability to suppress the regrowth and expansion of woody taxa in landslide areas (i.e. concavities) seems limited, as these types were less used. Our results suggest that reindeer use of the landscape and hence their effects on the landscape correlates with the landscape structure. Future research is needed to evaluate the role and efficiency of reindeer as ecosystem engineers capable of mediating the effects of climate change.
A fourth-order superintegrable system with a rational potential related to Painlevé VI
Authors: Marquette Ian , Post Sarah , Ritter Lisa
Published: October 2020

In this paper, we investigate in detail a superintegrable extension of the singular harmonic oscillator whose wave functions can be expressed in terms of exceptional Jacobi polynomials. We show that this Hamiltonian admits a fourth-order integral of motion and use the classification of such systems to show that the potential gives a rational solution associated with the sixth Painlevé equation. Additionally, we show that the integrals of the motion close to form a cubic algebra and describe briefly deformed oscillator representations of this algebra.
Smoking regular and low-nicotine cigarettes results in comparable levels of volatile organic compounds in blood and exhaled breath
Authors: Pauwels Charlotte G G M , Hintzen Kim F H , Talhout Reinskje , Cremers Hans W J M , Pennings Jeroen L A , Smolinska Agnieszka , Opperhuizen Antoon , Van Schooten Frederik J , Boots Agnes W
Published: October 2020

Smokers are exposed to more than 6000 (toxic) smoke components including volatile organic compounds (VOCs). In this study VOCs levels in headspace of blood and exhaled breath, in the mainstream smoke of three types of cigarettes of one brand varying in declared tar, nicotine and carbon monoxide (TNCO) yields are investigated. The objective was to identify whether VOC levels correlate with TNCO yields of cigarettes smoked according to ISO 3308. Our data show that smoking regular and low-TNCO cigarettes result in comparable levels of VOCs in blood and exhaled breath. Hence, declared TNCO-yields as determined with the ISO 3308 machine smoking protocol are irrelevant for predicting VOC exposure upon human smoking.

Venous blood and exhaled breath were sampled from 12 male volunteers directly before and 10 min after smoking cigarettes on 3 d (day 1 Marlboro Red (regular), day 2 Marlboro Prime (highly ventilated, low-TNCO), day 3 Marlboro Prime with blocked filter ventilation (taped)). Upon smoking, the levels of toluene, ethylbenzene, m/p-xylene, o-xylene, and 2,5-dimethylfuran in both headspace of venous blood and exhaled breath increase within the same range for all three cigarette types smoked. However, no strong correlation was found between VOC levels in exhaled breath and VOC levels in headspace of blood because of variations between the individual smoking volunteers. More research is required in order to use exhaled breath sampling as a non-invasive quantitative marker for volatile toxicants from cigarette smoke exposure of different brands.
Cerebral Approach to Track Malfunction of Assets in a Smart Power Grid Information System
Authors: Sayed B T , Dekdouk A , Ashraf Y , Chaudhry S
Published: October 2020

Failure of assets at downstream level of Smart Power Grid being barely addressed, subsequently hoarding lots of superfluous human hours, depletion of valuable time and resources, inefficient and untimely rectification of problems leading to concerns of inefficient operations and hefty loss to the power grid organization in all its aspects. There is a need to address such failures in advance, through the use of prevailing information technological inclusion, implicating efficient operations benefiting the entire sector. With Knowledge Management Systems evolving at its growing needs to address critical issues and providing feasible solutions to the digitization of information already at high demand, we propose an analytical approach merged with the concepts of big data, to track historical data of assets and resources, to identify the possibilities of failure of assets in smart power grid infrastructure. The proposed system would identify the possible failure based on the past records of an assets performance and failures, not limited to, but also based on the expected life span of the assets. The issues will be archived for further sharing while in apposite needs and its solutions would be appropriately applied throughout the power business and its subsidiary. The data would be efficiently stored and archived in the form of digitized formats such as audio, video, images, comments, documents, feedback and other visually recognizable and multimedia formats. Various technological related electronics and gadget equipment’s such as tablets, mobile phones, laptops and other hand held devices could be easily utilized to support the work force teams towards an agile operation.
Research on Regional Micro-meteorological Measurement System for the Operation Control of Distribution Network List the author names here
Authors: Gu Yang , Zhang Shuo , Dai Xin , Lu Yongcan , Wang Yang
Published: October 2020

With large number of wind power and grid-connected photovoltaic system, the ratios of renewable power greatly increase. However, random variations of the meteorological environment usually have a huge impact on the output of the renewable power, also the performance and stability of power grid. Hence, a local meteorology real-time monitoring technique is really needed. In this paper, a local micro-meteorological monitoring system is proposed, which takes temperature, wind speed, wind direction, and illumination intensity into account. The measurements would provide a reliable real-time meteorological data for power supply forecast and operation reference of distribution network. The hardware and software design are discussed. Finally, a prototype is developed.
Coordinated Control of Power and Current for Grid-connected Inverter under Unbalanced Voltage
Authors: Yue Youjun , Cheng Min
Published: October 2020

Grid-connected inverter is the grid-connected interface of new energy, but in unbalanced power grid, there will be output power oscillation, current imbalance and other problems. Based on the mathematical model of Grid-connected inverter alpha beta stationary reference system, the generalized power reference compensation expressions of adjustable current imbalance and power fluctuation are derived, which suppresses the active-power oscillation, reactive-power oscillation and balanced current respectively. It is established to achieve the coordinate control of power and current, which enhances the operation performance of the system. Finally, the simulation results verify the effectiveness of the proposed control strategy.
Assessment and analysis of programs for the management of transport infrastructure construction projects
Authors: Bovteev Sergei , Mishakova Anastasiia
Published: October 2020

The use of probabilistic non-alternative network models for planning investment construction projects has been thoroughly studied and has been widely used in construction practice for several decades. One of the common methods based on such models is the Program Evaluation and Review Technique. This method is for planning the project dates in which the durations of all or some of activities cannot be unambiguously determined due to the high degree of uncertainty in the external environment in which such projects are implemented. However, the problem of controlling the deadlines and milestones of an investment construction project based on the Program Evaluation and Review Technique has not been studied well enough. This article investigates the possibilities of applying the Program Evaluation and Review Technique to track and control the construction project schedule. A method based on monitoring the values of the probability function of the timely completion of the project is presented. The method takes into account possible deviations of the predicted completion date of the project and, if they exceed the established limits, prescribes the initiation of corrective measures. We give recommendations for improving the Program Evaluation and Review Technique that reduce its shortcomings in applying for control the construction period. The greatest effect can be obtained by combining the Program Evaluation and Review Technique with other known methods, in particular, the Critical Chain Project Management.
Documentation management system for construction control at a transport construction site
Authors: Perunov A S , Baulin A V
Published: October 2020

The article shows the role of construction control in the construction of transport construction objects. The necessity of its implementation, starting from the early stages of construction, is justified. Reviewed a detailed list of accounting documents for carrying out construction supervision on objects of transport construction. For each document, the procedure for its preparation and frequency of submission to the customer or representatives of the contractor are described. A detailed list of reporting documents on construction supervision at transport construction facilities is considered, including conclusions on the verifiability of design and working documentation for the transport construction object, conclusion on the readiness of contractors to perform construction, reconstruction, capital repairs, conclusion on the readiness of the construction laboratory of the nondestructive testing laboratory, electrical laboratory, within the framework of the construction contractor’s activities, when performing construction, reconstruction, capital repairs, conclusion on conformity assessment is made of the object and its willingness to carry out the work of the Commission, preparation of General journal and construction supervision, charting object, act, visual-measuring control, weekly and monthly reports, act of acceptance-transmission equipment (materials) on the project of the act on the identified equipment defects (materials), reference for the audit and approval of acts examination of the hidden works, draw conclusions about the dynamics of performance., preparation of a report on the actual time of rendering construction control services at the customer’s facility. The article presents an algorithm for document management based on the assessment of the work of several enterprises, which allows for high-quality construction control on construction sites.
Basic stages of creating a BIM model for transport infrastructure objects
Authors: Korolev Vadim , Shishkina Irina , Lokteva Victoria
Published: October 2020

This study discusses computer-aided design systems used by design organizations and created on the basis of modern computer systems and automation methods. Deficiencies of existing systems and complexes are identified, which necessitates further work on design automation. The next stage of automation and increase in labor productivity of design engineers is considered. The important problem is considered in detail when increasing the role of information and computing systems and processes in designing, namely, the need for automated verification of information models to search for errors and to bring them into accordance with rules and regulations.
Outdoor carports for automobile transport
Authors: Ilyin Sergei , Kondrateva Ludmila , Lazarev Vladimir
Published: October 2020

Carports for transport parking as well as for unloading and loading are highly-demanded engineering structures. Open metal carports of medium spans have been considered. The influence of some structural solutions of carports on the consumption of material has been evaluated. The calculation of the carports frames has been carried out using the LIRA software package. Recommendations for choosing options for carports frames with lower material consumption have been given.
Method of dry construction of prefabricated reinforced concrete building
Authors: Demiche Y , Vorona-Slivinskaya L , Voskresenskaya E
Published: October 2020

The existing systems of dry assembly of structures from prefabricated components still require the concreting of joints, which does not allow minimizing the number of technological processes and does not eliminate the need to wait until the concrete mixture hardens. Therefore, the period of erecting a building does not reduce significantly. The present paper describes the system of dry construction assembly from prefabricated components of reinforced concrete without application of any welding or casting-in-place while performing the above-ground works, which is feasible due to the bolt connection of all components. Since no welding or concreting is required, the duration and labor intensity of the erection process reduces. The present research is aimed at working out such a system of erecting a prefabricated building of reinforced concrete, which would allow moving away from welding and joint concreting, at the same time ensuring the structural reliability. This would reduce the duration and labor intensity of the construction process. The proposed system of prefabricated dry construction assembly of reinforced concrete structures that has a plenty of advantages by virtue of its nature can be easily implemented in low- and mid-rise residential construction and for erection of industrial, public and business buildings, buildings on railway transport intended for technical operation of Railways and maintenance of transport construction objects. Moreover, the system proposed could be a perfect choice for the erection of such temporary structures as sports facilities, hospitals, parking garages and warehouses, since it is easily disassembled.
Scientific and technical maintenance of transport infrastructure facilities
Authors: Davidyuk A
Published: October 2020

The work aimed to determine the concepts of scientific training, the relationship of this concept with the scientific and technical maintenance of design, the definition of goals, consideration of the current state of the issue, the identification of problems of this type of activity, the definition of the scope of work in the preparation and maintenance of design and the suggestion of a further development path. The methods of the study were the analysis of the current regulatory documentation and the identification of provisions that normalize scientific preparation and scientific and technical maintenance of design, the collection and analysis of publications on topics related to the topic of this article, the analysis of the experience of this type of activity by various organizations, the subsequent generalization of the analysis results and the formation conclusions. As a result of the study, the concepts of scientific preparation and scientific and technical maintenance of design were established, the relationship between these concepts was established, the composition of work for this type of activity was determined - the minimum standardized, typical and advanced. A circle of problems and questions was also identified that accompanies the implementation of scientific and technical maintenance of design, including requirements for the results of work and their executors, criteria for the need for STMP (scientific and technical maintenance of design). In conclusion, the urgency of the problem is indicated, a way to solve it and a possible positive effect are proposed. This study substantiates the need for the development of regulatory documentation containing various requirements, norms and criteria concerning activities for scientific and technical maintenance of design.
Optimization of transport and logistics processes in agriculture
Authors: Ermakova Anna , Cherezova Natalia
Published: October 2020

This article discusses the optimization of transport and logistics processes in an agricultural enterprise. The use of new engineering support will allow the company to significantly reduce its costs and energy resources. The recommendations received are quite relevant and justified, and will find appropriate application in the production and economic activities of an enterprise of a certain industry affiliation.
Improving the national logistics model on an international scale in the context of the economic crisis
Authors: Karanina Elena , Selezneva Ekaterina , Chuchkalova Svetlana
Published: October 2020

Active international processes, the growth of the scale and number of transnational corporations have created the need for introducing global logistics chains and channels into the business system, primarily in the distribution of goods, and determined the formation of an independent logistics services market. But at the same time, during the period of the economic crisis, non-standard situations, such as a pandemic, border closures, the logistics business is one of the first to bear risks and losses both domestically and abroad. International practice shows that the effective development of transport and logistics systems at the national level stimulates the accelerated development of related industries and sectors of the economy. For the Russian Federation, located at the crossroads of international transport routes, the problem of matching global trends and strengthening its position in the market of transport and logistics services as an important logistics sector is becoming increasingly urgent. Logistics is becoming one of the quality elements for the implementation of the country’s transit potential. The development of the information and logistics segment and the creation of multimodal transport and logistics centers in the transport infrastructure will increase the competitiveness of transport services. The aim of the study is to analyze and improve the national logistics model on an international scale in the conditions of the economic crisis. The objectives of the study are: 1. Consideration of logistics models in international transport. 2. To analyze the model of logistics in the Russian Federation. 3. Development and implementation of improvements to the logistics model by forming a multimodal logistics product for national companies.