bluuebunny/crossref_metadata_2025 huggingface dataset:
Stability of pinned surface nanobubbles against expansion: Insights from theory and simulation
Authors: Liu Yawei , Bernardi Stefano , Widmer-Cooper Asaph
Published: July 2020

While growth and dissolution of surface nanobubbles have been widely studied in recent years, their stability under pressure changes or a temperature increase has not received the same level of scrutiny. Here, we present theoretical predictions based on classical theory for pressure and temperature thresholds (pc and Tc) at which unstable growth occurs for the case of air nanobubbles on a solid surface in water. We show that bubbles subjected to pinning have much lower pc and higher Tc compared to both unpinned and bulk bubbles of similar size, indicating that pinned bubbles can withstand a larger tensile stress (negative pressure) and higher temperatures. The values of pc and Tc obtained from many-body dissipative particle dynamics simulations of quasi-two-dimensional (quasi-2D) surface nanobubbles are consistent with the theoretical predictions, provided that the lateral expansion during growth is taken into account. This suggests that the modified classical thermodynamic description is valid for pinned bubbles as small as several nanometers. While some discrepancies still exist between our theoretical results and previous experiments, further experimental data are needed before a comprehensive understanding of the stability of surface nanobubbles can be achieved.
Real-time monitoring the growth of strained off-stoichiometric NixFe3−xO4 ultrathin films on MgO(001)
Authors: Rodewald J. , Thien J. , Pohlmann T. , Hoppe M. , Bertram F. , Kuepper K. , Wollschläger J.
Published: July 2020

Ni x Fe 3 − x O4 thin films with varying Ni amount (0 ≤ x ≤ 1.5) were deposited on MgO(001) via reactive molecular beam epitaxy. The growth process was monitored during film deposition by means of X-ray diffraction. All prepared films exhibit a well-ordered structure with complete vertical crystallinity throughout the whole film growth and flat surfaces of the final films independent of the Ni amount. An enhancement of the vertical compression in the initial growth continuously decreases up to a film thickness of 8 nm. During further growth, all films exhibit residual and constant vertical compression with lateral adaption of the final films to the substrate lattice, as observed by high energy surface X-ray diffraction experiments. Hard X-ray photoelectron spectroscopy measurements of the final films reveal increasing Fe3+:Fe2+ ratios for higher Ni content and point to additional NiO agglomerations within the films exceeding the stoichiometric Ni amount of x = 1.
An immersed boundary-lattice Boltzmann method for thermal and thermo-solutal problems of Newtonian and non-Newtonian fluids
Authors: Kefayati Gholamreza
Published: July 2020

An immersed boundary-lattice Boltzmann method is introduced that can be employed for different thermal and thermo-solutal problems of Newtonian and non-Newtonian fluids. The general macroscopic and mesoscopic equations are presented and discussed. It is shown and proved that the macroscopic equations are satisfied by the proposed lattice Boltzmann equations. This approach removes the limitation of the conventional lattice Boltzmann method in constitutive equations and boundary conditions. To validate the accuracy of the method, it is compared against several cases of complex geometries with curved boundaries for natural convection in enclosures. To demonstrate the ability of this method for the simulation of thermo-solutal flows of non-Newtonian fluids with curved boundaries, double diffusive natural convection of Carreau fluid between a square cylinder and two circular cylinders is investigated and results are reported. Next, double diffusive mixed convection of a Bingham fluid in a cavity with a curved boundary condition is studied.
Multilevel reversible laser-induced phase transitions in GeTe thin films
Authors: Ionin V. V. , Kiselev A. V. , Eliseev N. N. , Mikhalevsky V. A. , Pankov M. A. , Lotin A. A.
Published: July 2020

This paper presents the results of a study on the structural properties and dynamics of conductivity of thin (d ∼ 100 nm) films of germanium telluride depending on the phase states reversibly switched by nanosecond pulsed laser radiation with a «top hat» beam profile. It was determined that the threshold of laser radiation energy density at which the phase transition in GeTe thin films from the amorphous to crystalline state is in the range of E = 7.5 ÷ 47.6 mJ/cm2, and the threshold for the reverse transition from the crystalline to amorphous state starts from 47.6 mJ/cm2 and is observed up to 90 mJ/cm2 with no visible damage caused by the ablation. The full time of conductivity change associated with the phase transition between the amorphous and crystalline phases is τCA = 20.2 ns, while for the reverse crystalline to amorphous transition, the conductivity full change time it makes τAC = 52 ns.
High-efficiency focused optical vortex generation with geometric gap-surface plasmon metalenses
Authors: Tang Shiwei , Ding Fei
Published: July 2020

Optical vortices (OVs) carrying orbital angular momentum have been an emerging research area due to their widespread applications ranging from optical communication to particle trapping. However, conventional OV generators suffer from bulky configurations and limited performance. Here, we design and experimentally demonstrate high-efficiency focused OV generation by using geometric gap-surface plasmon metalenses with spin-flipped focal planes, where the polarization states, positions, and corresponding topological charges of the OVs can be controlled by changing the spin of incident circularly polarized light, reproducing thereby the combined functionalities of a lens and a q-plate. The fabricated dual-polarity OV metalens features the polarization conversion ratios above 88% and efficiencies exceeding 50% for both right-handed and left-handed circularly polarized light in a wide wavelength range of 850 to 1000 nm. We further extend this approach to realize a multiple-focal OV metalens with distinct and spin-multiplexed OVs at four different longitudinal focal planes. Compared to conventional OV generators, the proposed OV metalenses are compact, ultrathin, and multiplexed, therefore opening an innovative avenue for advanced research and applications aiming at multiple functionalities and dense integration in photonics.
Visible pump–mid infrared pump–broadband probe: Development and characterization of a three-pulse setup for single-shot ultrafast spectroscopy at 50 kHz
Authors: Montanaro Angela , Giusti Francesca , Colja Matija , Brajnik Gabriele , Marciniak Alexandre M. A. , Sergo Rudi , De Angelis Dario , Glerean Filippo , Sparapassi Giorgia , Jarc Giacomo , Carrato Sergio , Cautero Giuseppe , Fausti Daniele
Published: July 2020

We report here an experimental setup to perform three-pulse pump–probe measurements over a wide wavelength and temperature range. By combining two pump pulses in the visible (650 nm–900 nm) and mid-IR (5 μm–20 μm) range, with a broadband supercontinuum white-light probe, our apparatus enables both the combined selective excitation of different material degrees of freedom and a full time-dependent reconstruction of the non-equilibrium dielectric function of the sample. We describe here the optical setup, the cryogenic sample environment, and the custom-made acquisition electronics capable of referenced single-pulse detection of broadband spectra at the maximum repetition rate of 50 kHz, achieving a sensitivity of the order of 10−4 over an integration time of 1 s. We demonstrate the performance of the setup by reporting data on a mid-IR pump, optical push, and broadband probe in a single crystal of Bi2Sr2Y0.08Ca0.92Cu2O8+δ across the superconducting and pseudogap phases.
Deriving Chinese alternative questions
Authors: Huang Rui-heng Ray
Published: July 2020

This study proposes an approach which derives Chinese alternative questions by means of feature percolation and LF movement. This approach is argued to fare better than a movement approach as proposed byC.-T. Huang (1998)and a non-movement binding approach as proposed byR.-H. Huang (2010)in that it may successfully explain why Chinese alternative questions are only sensitive to the wh-island constraint, but not to other types of island constraints. The LF movement analysis may receive empirical support from the observed fact that Chinese alternative questions exhibit focus-intervention effects, generally assumed to be induced by LF movement.
Differences in the lexical variation of reporting verbs in French, English and Czech fiction and their impact on
translation
Authors: Nádvorníková Olga
Published: July 2020

The aims of this paper are to analyse differences in the degree of lexical variation (type/token ratio and
hapax/token ratio) of reporting verbs in reporting clauses placed medially or in postposition in English, French and Czech fiction
and to evaluate their consequences in translation, especially in regard to explicitation/implicitation. We expect that, in
translations from a language with a low degree of lexical variation of reporting verbs into a language with a high degree of
lexical variation, the frequency and the degree of explicitation will be higher than in translations involving languages less
different with respect to lexical variation. The analysis, relying on data extracted from the InterCorp multilingual corpus,
proposes a classification of reporting verbs based on the type and amount of information conveyed, which allows evaluating the
degree of explicitation operated in translations. The results show that most shifts involve only the neutral reporting verb
say/dire, replaced by a stylistically more specific synonym or by a verb explicitating information obvious
from the context. This suggests that modifications of reporting verbs in translation are motivated primarily by respect for the
stylistic norm of the target language and the degree of acceptability of the repetition of the neutral reporting verb.
Can the maze task be even more amazing?
Authors: Gallant Jordan , Libben Gary
Published: July 2020

The maze task (Forster, Guererra & Elliot, 2009; Forster, 2010) is designed to measure focal lexical and sentence processing effects in a highly controlled manner. We
discuss how this task can be modified and extended to provide a unique opportunity for the investigation of lexical effects in sentence
context. We present results that demonstrate how the maze task can be used to examine both facilitation and inhibition effects. Most
importantly, it can do this while leaving the target sentence unchanged across conditions. This is an advantage that is not available with
other paradigms. We also present new versions of the maze task that allow for the isolation of specific lexical effects and that enhance the
measurement of lexical recognition through visual animation. Finally, we discuss how the maze task brings to the foreground the extent to
which complex multi-layered priming and inhibition are intrinsic to sentence reading and how the maze task can tap this complexity.
Strategies for using metaphor in psychological treatment
Authors: Törneke Niklas
Published: July 2020

In most models of psychotherapy metaphor is considered an important aspect of communication. At the same time there is a need for a rationale to tell the clinician with what purpose and how to use metaphor for the benefit of the client. The present article suggests such principles, specifically based on a behavioral approach to human language, relational frame theory (RFT). This approach has co-developed with a specific model of psychotherapy: acceptance and commitment therapy (ACT) and the conclusions in this article are very much in line with that model. Overlap between RFT and a recent linguistic theory of metaphor, the dynamic approach, is also discussed.
A novel GSK3 inhibitor that promotes self-renewal in mouse embryonic stem cells
Authors: Kobayashi Hiroki , Nishimura Haruna , Kudo Norio , Osada Hiroyuki , Yoshida Minoru
Published: July 2020

Small molecules that regulate cell stemness have the potential to make a major contribution to regenerative medicine. In the course of screening for small molecules that affect stemness in mouse embryonic stem cells (mESCs), we discovered that NPD13432, an aurone derivative, promoted self-renewal of mESCs. Normally, mESCs start to differentiate upon withdrawal of 2i/LIF. However, cells treated with the compound continued to express endogenous Nanog, a pluripotency marker protein essential for sustaining the undifferentiated state, even in the absence of 2i/LIF. Biochemical characterization revealed that NPD13432 inhibited GSK3α and GSK3β with IC50 values of 92 nM and 310 nM, respectively, suggesting that the compound promotes self-renewal in mESCs by inhibiting GSK3. The chemical structure of the compound is unique among known molecules with this activity, providing an opportunity to develop new inhibitors of GSK3, as well as chemical tools for investigating cell stemness.
Comment on ‘A note on Purcell’s basic explanation of magnetic forces’
Authors: Santos Aroaldo S , de Melo e Souza Reinaldo , Farina C
Published: July 2020

In his seminal book on electromagnetism, Purcell presented a conceptually rich discussion in which he used Lorentz contraction to relate the electromagnetic fields of a current-carrying wire when observed from different inertial frames. In a recent paper D’Abramo (2020 Eur. J. Phys. 41 025203) argued that Purcell’s approach has a very limited validity and when it is applied in examples slightly different from those considered by Purcell it can lead to violations of basic tenets of electromagnetism, such as charge invariance and the principle of relativity. In this comment we dispute this conclusion by demonstrating that Purcell’s approach for an arbitrarily shaped current loop is equivalent to performing a Lorentz transformation and is thus valid as long as we relate fields in inertial frames. In addition, we examine some of D’Abramo’s examples.
Angular emission distribution of O 1s photoelectrons of uniaxially oriented methanol
Authors: Kaiser L , Fehre K , Novikovskiy N M , Stindl J , Tsitsonis D , Gopakumar G , Unger I , Söderström J , Björneholm O , Schöffler M , Jahnke T , Dörner R , Trinter F , Demekhin Ph V
Published: July 2020

The angular distribution of O 1s photoelectrons emitted from uniaxially oriented methanol is studied experimentally and theoretically. We employed circularly polarized photons of an energy of hν = 550 eV for our investigations. We measured the three-dimensional photoelectron angular distributions of methanol, with the CH3–OH axis oriented in the polarization plane, by means of cold target recoil ion momentum spectroscopy. The experimental results are interpreted by single active electron calculations performed with the single center method. A comparative theoretical study of the respective molecular-frame angular distributions of O 1s photoelectrons of CO, performed for the same photoelectron kinetic energy and for a set of different internuclear distances, allows for disentangling the role of internuclear distance and the hydrogen atoms of methanol as compared to carbon monoxide.
Review on biophysical modelling and simulation studies for transcranial magnetic stimulation
Authors: Gomez-Tames Jose , Laakso Ilkka , Hirata Akimasa
Published: July 2020

Transcranial magnetic stimulation (TMS) is a technique for noninvasively stimulating a brain area for therapeutic, rehabilitation treatments and neuroscience research. Despite our understanding of the physical principles and experimental developments pertaining to TMS, it is difficult to identify the exact brain target as the generated electric field exhibits a non-uniform distribution owing to the complicated and subject-dependent brain anatomy and the lack of biomarkers that can quantify the effects of TMS in most cortical areas. Computational dosimetry has progressed significantly and enables TMS assessment by computation of the induced electric field (the primary physical agent known to activate the brain neurons) in a digital representation of the human head. In this review, TMS dosimetry studies are summarised, clarifying the importance of the anatomical and human biophysical parameters and computational methods. This review shows that there is a high consensus on the importance of a detailed cortical folding representation and an accurate modelling of the surrounding cerebrospinal fluid. Recent studies have also enabled the prediction of individually optimised stimulation based on magnetic resonance imaging of the patient/subject and have attempted to understand the temporal effects of TMS at the cellular level by incorporating neural modelling. These efforts, together with the fast deployment of personalised TMS computations, will permit the adoption of TMS dosimetry as a standard procedure in medical applications.
Dose rate determination for preclinical total body irradiation
Authors: Zhong Yuncheng , Lai Youfang , Saha Debabrata , Story Michael D , Jia Xun , Stojadinovic Strahinja
Published: July 2020

The accuracy of delivered radiation dose and the reproducibility of employed radiotherapy methods are key factors for preclinical radiobiology applications and research studies. In this work, ionization chamber (IC) measurements and Monte Carlo (MC) simulations were used to accurately determine the dose rate for total body irradiation (TBI), a classic radiobiologic and immunologic experimental method. Several phantom configurations, including large solid water slab, small water box and rodentomorphic mouse and rat phantoms were simulated and measured for TBI setup utilizing a preclinical irradiator XRad320. The irradiator calibration and the phantom measurements were performed using an ADCL calibrated IC N31010 following the AAPM TG-61 protocol. The MC simulations were carried out using Geant4/GATE to compute absorbed dose distributions for all phantom configurations. All simulated and measured geometries had favorable agreement. On average, the relative dose rate difference was 2.3%. However, the study indicated large dose rate deviations, if calibration conditions are assumed for a given experimental setup as commonly done for a quick determination of irradiation times utilizing lookup tables and hand calculations. In a TBI setting, the reference calibration geometry at an extended source-to-surface distance and a large reference field size is likely to overestimate true photon scatter. Consequently, the measured and hand calculated dose rates, for TBI geometries in this study, had large discrepancies: 16% for a large solid water slab, 27% for a small water box, and 31%, 36%, and 30% for mouse phantom, rat phantom, and mouse phantom in a pie cage, respectively. Small changes in TBI experimental setup could result in large dose rate variations. MC simulations and the corresponding measurements specific to a designed experimental setup are vital for accurate preclinical dosimetry and reproducibility of radiobiological findings. This study supports the well-recognized need for physics consultation for all radiobiological investigations.
Creating big time crystals with ultracold atoms
Authors: Giergiel Krzysztof , Tran Tien , Zaheer Ali , Singh Arpana , Sidorov Andrei , Sacha Krzysztof , Hannaford Peter
Published: July 2020

We investigate the size of discrete time crystals s (ratio of response period to driving period) that can be created for a Bose–Einstein condensate (BEC) bouncing resonantly on an oscillating mirror. We find that time crystals can be created with sizes in the range s ≈ 20–100 and that such big time crystals are easier to realize experimentally than a period-doubling (s=2) time crystal because they require either a larger drop height or a smaller number of bounces on the mirror. We also investigate the effects of having a realistic soft Gaussian potential mirror for the bouncing BEC, such as that produced by a repulsive light-sheet, which is found to make the experiment easier to implement than a hard-wall potential mirror. Finally, we discuss the choice of atomic system for creating time crystals based on a bouncing BEC and present an experimental protocol for realizing big time crystals. Such big time crystals provide a flexible platform for investigating a broad range of non-trivial condensed matter phenomena in the time domain.
Zero-bias anomaly and role of electronic correlations in a disordered metal film
Authors: Jeon Sangjun , Kim Sungmin , Kuk Young
Published: July 2020

Localization and electron correlation play significant roles in understanding the electronic states of low-dimensional systems. We carried out the tunneling spectroscopy measurements on a crystalline nano-sized island and a disordered two-dimensional metal film. The low temperature zero-bias anomaly was studied using

P

E

theory and statistical analysis of the spatial distribution of the local density of states in both the systems. The effective capacitance and resistance of the tunnel junction extracted from

P

E

theory gives the energy and temperature dependency of the measured ZBA. Statistical analysis reveals the electron correlation effect and the electron correlation length. By combining

P

E

theory and the statistical analysis, we found that the microscopic origin of ZBA formation in the disordered two-dimensional film is strongly related to the electron localization and the correlations.
An investigation on drought teleconnection with indian ocean dipole and el-nino southern oscillation for peninsular india using time dependent intrinsic correlation
Authors: Johny Kavya , Pai Maya L , Adarsh S
Published: July 2020

Drought is an obscure climatic state that has socioeconomic repercussions on power generation, agricultural production, forestry, tourism and construction. In this study, an Ensemble Empirical Mode Decomposition (EEMD) based Time Dependent Intrinsic Correlation (TDIC) analysis was conducted to assess the impacts of Indian Ocean Dipole(IOD) and El Niño-Southern Oscillation (ENSO) to drought events of Peninsular region in India. Standardized Precipitation Index (SPI) at three different time scales (SPI-3, SPI-6 and SPI-12) are considered for analysis. The teleconnections IOD and ENSO on the three indices are evaluated independently using TDIC method and the detection and attribution was made from the obtained correlation plots. From the detailed analysis, short term drought (SPI-3) is found to have better correlation with both IOD and ENSO. It is also interpreted that high frequency modes of SPI-3 have more association to IOD while low frequency modes show more correlation to ENSO. Thereby, IOD experiences a lagged influence on ENSO relation to rainfall. The IMF3 and IMF7 of SPI-12 also show positive association that can be added to existing data for efficient prediction of drought events. Similarly, for ENSO IMF1, IMF6 and IMF7 of SPI-6 and IMF6 and IMF7 of SPI-12 can also be used for determining the drought accurately.
Statistical downscaling and projection of future temperature change for Tabriz city, Iran.
Authors: Baghanam A H , Nourani V , Sheikhbabaei A , Seifi A J
Published: July 2020

In the 21st century, Climate change has become one of the prominent global challenges which threats the world, and the changes in climate extremes are estimated to have catastrophic consequences on human society and the natural environment. To overcome the spatial-temporal inadequacy of the GCMs, Linking large-scale General Circulation Model (GCM) data with small-scale local climatic data highly comes to the fore. In this paper, two statistical downscaling techniques encompass LARS-WG and SDSM were employed for assessing the fluctuations of temperature predictand in Tabriz city, Iran. In order to choose the well-response GCMs a Multi-GCM ensemble approach was utilized by EC-EARTH, HadCM2, MIROC5, MPI-ESM GCMs from the CMIP5. To study the impact of climate change over the region, the periods of 1961-1990 and 1991-2005 were used as the baseline and validation period, respectively. Results of evaluation criteria disclosed the superior performance of Multi-GCM ensemble for predicting temperature predictand compared to single GCM models. Furthermore, the result of climate projection for the temperature predictand by both models revealed that the city will experience an increasing trend in temperatures for the horizon of 2021-2080. The average temperature will increase by 2.9 and 3.7 (°C) under Representative Concentration Pathways (RCPs) (i.e., RCP4.5 and 8.5), respectively.
Estimation of probabilistic seismic hazard for Aizawl city in North Eastern India (NEI)
Authors: Rahman T , Ricky L , Chhangte
Published: July 2020

It is common practice to describe seismic hazard in terms of Peak Ground Acceleration (PGA) and Spectral acceleration (Sa). Response spectrum representation of ground motion is directly applicable in structural response analysis. However, in India, engineers have been using a standard response spectral shape as recommended by the code IS-1893:2016 all over the country, modified only by a zonal factor representing the PGA of unknown probability of occurrence. This approach is silent about the various seismo-tectonic sources and non-uniform level of hazard at different parts of India. Thus, the expected or desired design life of structures cannot rationally harmonize with existing earthquake hazard and economical construction practices. Whereas, the underestimation of the hazard will lead to questionable safety margins, overestimation makes the projects uneconomical and hence social goal suffers in either case. It is in this context, Probabilistic Seismic Hazard Assessment (PSHA) that addresses engineering safety issues with quantifiable risk levels has become more popular. Now-a-days, seismic hazard maps are prepared in different countries for a given annual frequency of exceedance. With this in mind, probabilistic seismic hazard for Aizawl City has been prepared.In this study, we have estimated seismic hazard for different return period in Aizawl city. The active fault within 300 km radius of the city are considered for this study. The seismic hazard values estimated in this study will be useful for the structural designers of Aizawl city and its adjacent region to design various types of Engineering Structures.
Rheological and mechanical characterization of self-compacting concrete with utilization of supplementary sustainable cementitious materials
Authors: Ealiyas Mathews Mervin , Anand N , Prince Arulraj G , Kiran Tattukolla
Published: July 2020

Self-Compacting Concrete (SCC) being a sustainable high-performance concrete capable of flowing through congested reinforcement and can fill the shuttering without any external energy. The investigation focuses on the effect of waste materials generated from industries on the fresh and mechanical properties of SCC. Experiments were carried out to develop SCC by using Fly Ash (FA) and Ground Granulated Blast Furnace Slag (GGBFS) as Supplementary Cementitious Material (SCM). Light weight Perlite Aggregates (PA) were used as a partial replacement material in M-Sand. Workability tests were conducted to check the rheological properties of developed SCC mix in accordance with the European Federation of National Associations Representing for Concrete (EFNARC) guidelines. An optimal mix was developed satisfying the criteria as per EFNARC. The developed mix design exhibited a significant reduction in cement content. Ordinary Portland Cement (OPC) was replaced with 31% of FA and GGBFS is kept constant at 31%. The specimens were cured in water under ambient temperature. Performance of the developed mix in terms of compressive strength at different ages of 7, 28, 56 and 90 days were also examined. The results showed that SCC developed with industrial wastes provide adequate workability and strength with a substantial reduction in the cement content. Hence, the developed SCC with FA and GGBFS along with PA can be used as a sustainable concrete due to its high strength for the infrastructure development.
Effect of reduced graphene oxide on the mechanical properties of concrete
Authors: Jyothimol P , Hazeena R , Issac Manoj T , Mathiazhagan A
Published: July 2020

Reduced Graphene oxide (rGO) is a 2D nanoplane fiber that contains highly reactive hydroxyl, epoxide, carboxyl, and carbonyl functional groups. These oxygen bearing functional groups increases solubility in cement matrix and serve as a nucleation agent for C-S-H crystals. rGO can serve as a reinforcing material in cement composites and can improve the mechanical properties of cement-based materials. This paper presents the mechanical properties of concrete modified with 0.03%, 0.05% and 0.07% reduced grapheme oxide by the weight of the OPC. Compressive strength of concrete was found to be increased by rGO especially the early age strength due the hydration acceleration and reinforcement of cement matrix and strong adhesion between aggregate and cement matrix by rGO. The mechanical properties, compressive strength, split tensile strength, flexural strength and modulus of elasticity are found to be maximum at 0.05% rGO replacement by the weight of the cement. The properties were found to be decreased at 0.07% of rGO content due to the formation of the agglomerated structure and poor dispersion of rGO.
Effect of binder chemistry on sulphate resistance of fly-ash blended cement concrete mixes
Authors: Nazeer M , Narasimhan M C , Rajeeva S V
Published: July 2020

The chemical durability of concretes exposed to sulphate environment largely depends on the quality and quantity of products of cement hydration. Certain hydration products are readily reactive with the sulphate ions and form expansive products such as gypsum and ettringite. On the other hand, some sulphate compounds participate in reducing the cementing property of hydration products. These reactions cause expansion and deterioration of strength of concrete. Sulphate resistance of concrete can be improved by the incorporation of Supplementary Cementitious Materials (SCMs). Reduced water-binder ratio and proper curing can make concrete more durable in sulphate environment. This paper reports the details and results of an investigation of effect of chemical composition of binder materials on the sulphate resisting property of concrete exposed to a rich MgSO4 solution. The effect of initial curing is also investigated so that it may be possible to suggest the mix compositions for typical field applications of concrete. The variables investigated in this report are the oxide composition of binder components and the initial curing conditions. A set of concrete mixes, all with a constant binder content and water-binder ratio are used in the investigation.
Pile induced filtering of seismic ground motion in homogeneous soil
Authors: Varghese Ramon , Boominathan A , Banerjee Subhadeep
Published: July 2020

The foundation input motion (FIM) that a structure experiences during an earthquake, is known to be different from the free field ground motion due to soil structure interaction (SSI) effects. Kinematic interaction in a single pile can also introduce a rotational component to the FIM. Conventionally, soil structure interaction is performed by applying the free field ground motion to the structure ignoring the effects of kinematic interaction. Deep foundation elements such as piles are known to suppress certain frequencies of ground motion which in turn induces kinematic bending moments in them. In this study, kinematic soil pile interaction is simulated using 3D numerical models using a coupled finite element-boundary element method. Single pile, group pile and piled raft models in a homogeneous soil profile are analysed for vertically propagating shear waves. Three earthquake time histories with varying frequency content are considered in this study. Transfer functions are then plotted together to analyse the effects of pile induced filtering of ground motion. The ratio of response spectrum at the foundation level and free field ground, for the pile group considered, is found to closely follow the behaviour of a fixed headed single pile. It is found that embedment of the pile cap, as in the case of a piled raft can result in further filtering of ground motion.
Are the preferences of travelers same across cities? A tale of two Indian cities
Authors: Fairooz Cheranchery Munavar , Madhukumar Raji Prathibha , Surendran Silpa , Navab Nourin , Sindhu Nath Abhijith , Padu Kiyum
Published: July 2020

The paper reports an investigation on the preferences of travelers in two Indian cities. The importance of travelers was collected from Kolkata and Kollam cities using 5-point Likert-type importance scale, and RIDIT analysis was carried out to obtain the priority rankings of travelers. A three-level analysis was carried for travelers, captive riders (travelers without car), and choice riders (travelers with car) of the two cities. The priority ranking obtained for the travelers of two cities were then compared using Spearman’s rank correlation test. It was shown that there is a substantial difference in the perception of travelers from two cities. This was instrumental in establishing the fact that preferences of travelers are not transferable across the cities. Therefore, the selection of attributes for WTP studies require a separate investigation to understand the preference of travelers of the city under consideration. On-board safety was identified as a major concern for the travelers of Kolkata and Kollam cities, which clearly shows the importance of addressing safety issues for enhancing the quality of public transport. The results obtained from the present work is city specific. However, the derived insights are expected to encourage researchers and policymakers to carry out separate investigations in various cities for identifying important attributes prior to behavioural studies.
Preparation and Characterization of (Na0.48K0.52)(Nb0.90Sb0.10)O3 Lead-free Ferroelectric Ceramics With MnO2 Sintering Aids
Authors: Li Min , Yang Xiaohong , Chen Jianbing
Published: July 2020

Lead-free (Na0.48K0.52)(Nb0.90Sb0.10)O3-xwt% MnO2(x = 0.2, 0.8) ferroelectric ceramics were prepared by solid state sintering methods with MnO2 aids. The X-ray diffraction analysis revealed that the the (020) peak shifts to higher angles at x=0.8 suggested that the lattice parameters decreased. The reason is that the Mn4+ may entering the Nb5+sites. The largest maximum strain Smax was 0.13 % under 40 kV/cm at room temperature.
Research on Pipeline Robots with Obstacle Crossing and Turning Ability
Authors: Wei Hangxin , Cheng Panghu , Wang Xiaorong , Song Xinai
Published: July 2020

The pipeline robot will encounter complex conditions of turning, obstacles and pipe diameter changes when it works. Therefore, cornering performance, obstacle crossing performance, and diameter changing ability are important indicators of the pipeline robot performance. A multi-axis differential adaptive pipeline robot is designed. The multi-axis differential mechanism is used to realize the smooth turning of the robot. The pre-tightening and reducing mechanism is used to achieve the obstacle crossing of the robot and the ability to adapt to different pipe diameters. The overall structure of the pipeline robot, the transmission mechanism, and the pre-tightening and reducing mechanism are introduced. The kinematics model of the robot is studied when it crosses obstacles. Using the maximum height of the pipeline robot passing through obstacles as an indicator, an equation of the pipeline robot obstacle crossing is established. The ADAMS software is used to simulate the kinematics of the turning process of the pipeline robot. Through the simulation experiments, the following conclusions are obtained: (1) The larger the adhesion coefficient between the pipe wall and the wheel, the stronger the obstacle crossing ability of the pipeline robot. The larger the diameter of the wheel, the stronger the ability to overcome obstacles. (2) By tracking the changes in the angular velocity of the three driving wheels, it is shown that the pipeline robot can pass through the curve smoothly and has anti-motion interference performance.
Analysis and Research on the Change of Landscape Ecological Pattern in the Surrounding Area of Guishan in Yuyao City
Authors: Gao Yuanyuan , Zhao Tiezheng , Zhao Yang
Published: July 2020

In this study, the area around Guishan in Yuyao is taken as the research object, and data processing and analysis are carried out by using Fragstats 4.2 and other software. The changes of the land use landscape pattern in the area in 2012 and 2019 are analyzed to provide basic research for the future ecological sustainable planning and development of the area. The results show that the degree of landscape heterogeneity of the overall landscape pattern in the study area is gradually increasing, and land use is developing toward diversification and homogenization. This is because in the process of urbanization, the landscape ecological pattern in the study area will inevitably be affected by many factors and changed. Therefore, through quantitative analysis of the landscape ecological pattern change process in the study area, it can reflect more scientifically changing process, which is conducive to scientific and reasonable planning for the next step, and thus better maintain the balance of natural ecology. Through quantitative analysis of the landscape ecological pattern change process in the study area, it can reflect its change process more scientifically, which is conducive to the next step to provide a basis for scientific and rational planning and better maintain the balance of natural ecology.
Research on Environmental Quality Evaluation System of Coordinated Development of the Beijing-Tianjin-Hebei Region
Authors: Hao C X , Ge C Z , Qin J L , Chen Z W , Zhou Q , Qu A Y , Peng C , Li N , Dong Z F , Hu Rui
Published: July 2020

Since the coordinated development plan of Beijing-Tianjin-Hebei region was put forward, environmental protection and pollution control have become the primary breakthrough of coordinated development. The ecological environment problem in Beijing- Tianjin-Hebei region has been the bottleneck factor restricting the integrated development. It is of great significance for environmental protection and economic development to establish a coordinated assessment mechanism for ecological environment quality in Beijing-Tianjin- Hebei region. This study analyzed the progress and effectiveness of the assessment of ecological environment quality in Beijing-Tianjin-Hebei region, analyzed the problems and challenges in the assessment of ecological environment in Beijing-Tianjin-Hebei region, and put forward some suggestions on the establishment of the mechanism of joint environmental prevention and control under the coordinated development of Beijing-Tianjin-Hebei region.
Analysis of Carbon Emission Efficiency in Belt and Road Agriculture
Authors: Ye Du , Poyi Zhu , Yan Gong , Keshan Zhao , Shiwen Chen , Ying Zhou
Published: July 2020

This paper will calculate the carbon emissions and their growth rates in 30 regions except Tibet and Hong Kong, Macao and Taiwan. It will also outline 17 regions with strategic priorities along the Belt and Road: Xinjiang, Shaanxi, Gansu, Ningxia, Qinghai, Inner Mongolia, Heilongjiang, Jilin, Liaoning, Guangxi, Yunnan, Shanghai, Fujian, Guangdong, Zhejiang, Hainan and Chongqing. It will also calculate the carbon emissions share of major agricultural carbon sources. Based on the analysis of the influencing factors of agricultural carbon emission efficiency in the belt and road initiative, the SBM model and ML model are used to evaluate and analyze the agricultural carbon emission efficiency in the belt and road initiative region from the static and dynamic perspectives respectively. The results show that: (1) the average carbon emission in the belt and road initiative region from 2014 to 2017 is 4.4396 million tons, which is lower than the national average of 5.0883 million tons; (2) animal husbandry and cultivation activities become the two major sources of carbon emission; (3) from DEA model, it can be seen that the belt and road initiative region accounts for 5 of the 8 regions with effective carbon emission in 2017, while Heilongjiang province has the largest range of arable land and total power of agricultural machinery to be adjusted among the regions with carbon emission efficiency of 0.75 to 1. (4) During 2014-2017, the average ML index in the belt and road initiative region is 1.042, which is greater than 1, of which the average tech index is 1.045 and the average effch idex is 0.998, indicating that the overall agricultural carbon emission efficiency is on the rise.
Study on Composite Control Strategy of Transient Air-Fuel Ratio for Gasoline Engine Based on Model
Authors: Song Dandan , Li Yuelin
Published: July 2020

The control accuracy of transient air-fuel ratio of gasoline engine is a difficult problem in the current engine control system. To achieve effective control of transient air-fuel ratio for gasoline engines, a composite control method is proposed, which consists of inverse model feedforward based on least squares support vector machine(LS-SVM)and feedback control with model-free adaptive control(MFAC).Feedforward control can accurately estimate the intake air volume in the cylinder. Neither feedforward or feedback control can achieve better control results. A composite control strategy based on feedforward + feedback is proposed. The feedforward model is used to perform dynamic feedforward compensation of the intake air amount in the transient air-fuel ratio, and in combination with feedback control, the air-fuel ratio is feedback-controlled by modifying the fuel injection amount, and system disturbances and errors are corrected. In this paper, two composite control strategies are designed for the air-fuel ratio of the engine under transient conditions. The results show that the inverse model based on LS-SVM can accurately approximate the air fuel ratio transient process, and this method has stronger robustness and anti-interference combined the MFAC feedback control. Therefore, the composite control strategy has good control performances and can improve the control precision of air-fuel ratio in transient conditions.
Admittance and Management of Urban Industrial Lands
Authors: He Zhimin
Published: July 2020

Because of the increasingly serious situation of environmental protection and lands supply in China, the research on control technology of industrial lands must be carried out to eliminate the enterprises of outdated technology and overcapacity, optimize industrial structure and protect land resources. Through the methods of statistical analysis and comparative analysis, the paper studies the index system of industrial lands in typical cities of Yangtze River Delta, Pearl River Delta and the Central Urban Agglomeration, analyzes the problems existing in approval and management of industrial lands, and puts forward suggestions on the construction of the index system and management process of industrial lands.
Study on the Material Properties of Cement-sand-gravel
Authors: Li Xiuwen , Zhang Shunfu , Wu Hao , Tian Dongcheng
Published: July 2020

Cement-sand-gravel dam is a new type of dam. The low-strength cement-sand-gravel material with low price is used for dam construction. This material is obtained by simply mixing water with a small amount of cement in the sand gravel of river bed or excavation waste slag and other materials easy to get near the dam site. In this paper, the effects of water binder ratio, fly ash, sand ratio, stone powder and other parameters in different mix ratio design on the properties of materials are studied. The results show that: (1) water to binder ratio has a great influence on the strength of cement-sand-gravel material; (2) fly ash can increase the later strength of cement-sand-gravel material; (3) when the sand ratio exceeds 25%, with the increase of sand ratio, the compressive strength of cement-sand-gravel material decreases sharply; (4) stone powder has a significant effect on the early strength.
Characteristics and Perception of Cultural Tourism Resources in Mt. Huangshan Scenic Spot
Authors: Zhu Shengdong , Gan Zhuoting , Yu Xiangyang
Published: July 2020

Taking Huangshan Mountain Scenic Spot as the research object, this paper explores the types, characteristics and perception of the cultural tourism resources of the double heritage scenic spot through collecting previous literature, on-site investigation and comparative analysis and other research methods. The results show that: (1) There are four types of cultural resources in Mt. Huangshan Scenic Spot, namely, cliff stone carving, historical structure, literary works and cultural spirit; (2) Compared with Tai Mountain, Emei Mountain, Wuyi Mountain and other world cultural and natural heritage sites tourists have low perception of cultural tourism resources in Huangshan Mountain Scenic Spot; (3) Factors such as typical natural attribute, single tourism product and seasonal tourists flow are the main influencing factors of low perception of cultural tourism resources in Huangshan Mountain Scenic Spot. Paying attention to resource mining, strengthening product design and expanding the scope of publicity, etc. can increase tourists’ perception of cultural tourism resources in Huangshan Mountain Scenic Spot.
Research on the Application of Automatic Monitoring Software for Seismic Observation Instruments
Authors: Wang Zhe , Teng Yuntian
Published: July 2020

Combining with the actual monitoring work of seismic geophysical observation stations, a seismic monitoring instrument automatic monitoring software was developed. The software is suitable for real-time or regular automatic network monitoring of IP instruments and equipment under different network environments. Automatic monitoring of the clock, status and observation data of geophysical observation instruments, which can automatically identify invalid data and abnormal amplitude changes in the observation data of the day, interference, earthquake and amplitude limitation, etc. Without other hardware and software, the alarm information can be sent to the duty personnel and management personnel by SMS, which can realize automatic backup and manual recovery of the original observation data of the instrument, and One-click restart and clock correction and other control operations, you can view the integrity and validity of the observed data curve and analysis data of the day without cross-platform operation, thereby achieving unified and efficient management of the instrument.
A Fast Tile-Pyramid Construction Algorithm Based on Multilevel Task Parallelism
Authors: Liu Haozheng , Wu Ye , Jing Ning , Feng Shihao
Published: July 2020

With the rapid development of satellite sensor technology and aerial photography technology, spatial and temporal resolution of the remote sensing image has been greatly improved. To speed up the visualization of remote sensing images, pyramid building technology is the best choice at present. However, the performance of existing methods is not as good as expected. Considering the load imbalance problem caused by the uneven data distribution problem, this paper proposes a fast tile-pyramid construction algorithm based on multilevel task parallelism. Our method changed the traditional parallel tile generation algorithm which is generated layer by layer and implemented a new algorithm that generated multiple layers at the same time by using the entire tile pyramid as a whole. Experimental results on real-life datasets show that our new algorithm can improve the construction speed of tile-pyramids.