bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhanced suppression of low-frequency vibration transmission in metamaterials with linear and nonlinear inerters
Authors: Liu Yuhao , Yang Jian , Yi Xiaosu , Chronopoulos Dimitrios
Published: March 2022

This study proposes the use of a linear and geometrically nonlinear inerter-based resonator in locally resonant acoustic metamaterials (LRAMs) and evaluates the performance on low-frequency wave attenuation. The LRAM is modeled as a 1D chain system composed of mass-in-mass unit cells connected by springs, and the geometrical nonlinearity is achieved by two lateral inerters linking the resonator and lumped mass symmetrically with respect to the horizontal springs. For the nonlinear inerter-based LRAM, the dispersion relation is analytically derived by a complex Fourier transform and the harmonic balance method. Compared with the linear inerter-based LRAM, the proposed nonlinear inerter-based structure has the property of a low-frequency bandgap with sufficient width for longitudinal wave propagation without being sensitive to changes in the inertance ratio. The nonlinearity can extend the original material parameter restrictions, leading to a lower-frequency bandgap. The results of dispersion properties are validated by wave transmittance and vibration power flow diagrams obtained by using the method of effective mass. It is shown that an adequate number of unit cells can achieve better wave attenuation performance.
Mesh-free simulations of injection molding processes
Authors: Veltmaat Lennart , Mehrens Felix , Endres Hans-Josef , Kuhnert Jörg , Suchde Pratik
Published: March 2022

In this paper, we introduce a mesh-free numerical framework using the finite pointset method for the modeling and simulation of injection molding processes. When compared to well-established mesh-based methods, which have been widely applied for these applications, our approach avoids the need for extensive preprocessing and enables accurate treatment of free surfaces and other associated phenomena. To accurately model the polymer injections, we consider a detailed material model, with temperature dependent viscosity and density, while also considering shear thinning behavior with a strain rate dependent viscosity. Our numerical investigations show that injection molding-specific problems such as the modeling of viscous flows and the fountain flow effect can be successfully implemented using our presented framework. For a thorough validation of our proposed model, we compare the simulated flow behavior with injection molding experiments, which are also performed in this work. The experimental setup considers the injection of a polymer melt into a spiral mold. The flow behavior is investigated experimentally at varying melt injection and wall temperature, with different threshold pressures. Our numerical simulations show a good comparison with these experimental results, both qualitatively and quantitatively. We also introduce a correction mechanism to ensure energy conservation, which has often been challenging in mesh-free approaches. This is the first time that the flow behavior in a mesh-free injection molding method has been experimentally validated and successfully applied to the simulation of an actual industrial vehicle component.
Space charge and trap energy level characteristics of SiC wide bandgap semiconductor
Authors: Chen Chi , Wang Xia , Wu Kai , Cheng Chuanhui , Wang Chuang , Fu Yuwei , Zhang Zaiqin
Published: March 2022

Charge carrier transport and accumulation in silicon carbide (SiC) wide bandgap semiconductors caused by the defect and impurity are likely to lead to serious performance degradation and failure of the semiconductor materials, and the high temperature effect makes the charge behaviors more complex. In this paper, charge carrier transport and accumulation in semi-insulating vanadium doped 4H–SiC crystal materials and the correlated temperature effect were investigated. Attempts were made to address the effect of deep trap levels on carrier transport. A combination of pulsed electro-acoustic direct space charge probing, an electrical conduction·current experiment, and x-ray diffraction measurement was employed. Space charge quantities including trap depth and trap density were extracted. The results show hetero-charge accumulation at adjacent electrode interfaces under a moderate electrical stress region (5–10 kV/mm). The charge carrier transports along the SiC bulk and is captured by the deep traps near the electrode interfaces. The deep trap energy levels originating from the vanadium dopant in SiC crystals are critical to carrier transport, providing carrier trapping sites for charges. This paper could promote the understandings of the carrier transport dynamic and trap energy level characteristic of SiC crystal materials.
State-averaged CASSCF with polarizable continuum model for studying photoreactions in solvents: Energies, analytical nuclear gradients, and non-adiabatic couplings
Authors: Song Chenchen
Published: March 2022

This paper presents state-averaged complete active space self-consistent field in polarizable continuum model (PCM) for studies of photoreactions in solvents. The wavefunctions of the solute and the PCM surface charges of the solvent are optimized simultaneously such that the state-averaged free energy is variationally minimized. The method supports both fixed weights and dynamic weights where the weights are automatically adjusted based on the energy gaps. The corresponding analytical nuclear gradients and non-adiabatic couplings are also derived. Furthermore, we show how the new method can be entirely formulated in terms of seven basic operations, which allows the implementation to benefit from existing high-performance libraries on graphical processing units. Results demonstrating the accuracy and performance of the implementation are presented and discussed. We also apply the new method to the study of minimal conical intersection search and photoreaction energy pathways in solvents. Effects from the polarity of the solvents and different formulas of dynamic weights are compared and discussed.
Frequency of narasin intake affects ruminal metabolism and growth of lambs
Authors: Oliveira Gabriela B. , Polizel Daniel M. , Bertoloni Analisa V. , Ferraz Marcos V. C. , Miszura Alexandre A. , Barroso José P. R. , Martins André S. , Pasqualino Letícia F. , Biava Janaina S. , Ferreira Evandro M. , Pires Alexandre V.
Published: March 2022

Context Ionophores improve rumen fermentation efficiency, average daily gain (ADG) and feed efficiency. However, the effects of providing ionophores to grazing animals are extremely variable, primarily due to infrequent supplement intake. Aim This study aimed to evaluate the effect of frequency of narasin intake on ruminal fermentation, nutrient digestibility and growth of lambs. Methods In Experiment I (metabolism assay), four rumen-cannulated wethers (1/2 Dorper × 1/2 Santa Inês) were assigned to a 4 × 4 Latin square design. The four treatments included a control, where animals were fed a diet without ionophore, and the following three treatments where animals were fed narasin at different intervals: 13 mg/kg of narasin every 24 h (N24), 26 mg/kg of narasin every 48 h (N48) and 39 mg/kg of narasin every 72 h (N72). All animals were fed with 95% Tifton-85 hay and 5% ground corn that was used as a vehicle for narasin. In Experiment II, 44 lambs (1/2 Dorper × 1/2 Santa Inês; 33.3 ± 0.5 kg (mean ± s.e.m.) and 180.5 ± 8 days of age) were used in a randomised complete-block design to assess performance. All treatments and management were similar to those in Experiment I. Key results Experiment I, dry-matter intake and apparent digestibility of nutrients were not affected by the treatments. The treatments N24 and N48 increased (P < 0.01) the total molar concentration of short-chain fatty acids compared with control and N72, and increased (P < 0.01) the concentration of propionate compared with control. In Experiment II, the treatments N24 and N48 increased the liveweight gain (P = 0.03) and feed efficiency (P = 0.02) compared with control and N72. Conclusion Effectiveness of narasin was reduced when offered at intervals greater than 48 h. Implication Frequency of narasin intake affects lamb production, and feeding systems are required where animals consume supplements on a regular basis.
Evaluating the performance and profitability of varied combinations of brewery by-products for fattening pigs
Authors: Beyihayo Geoffrey A. , Rukundo Eugene , Mwesigwa Robert , Lwanga Timothy , Kabugo Stephen
Published: March 2022

Context The consumption of pork is rapidly increasing in Uganda and presents an opportunity for pig farmers to maximise profits. However, the population and productivity of pigs remains low and this is attributed to the high cost of commercial feeds. Aims We aimed to evaluate the effects of various combinations of brewery by-products on the performance, carcass characteristics and profitability of fattening pigs. Methods The study involved 48 crossbred (Large White × Camborough) pigs weaned at 2 months of age and weighing 10.3 ± 1.2 kg. Group pens of four pigs, balanced for sex and weight, were assigned in a completely randomised design with three replications to four diets: BYM, 22% brewers’ spent grain + 15% yeast cake + 60% malt dust; BY, 33% brewers’ spent grain + 14% yeast cake (with 50% maize bran); YM, 27% yeast cake + 70% malt dust; and a commercial diet (control). Feed intake and efficiency, costs and carcass characteristic were determined. Key results Feeding brewery by-products increased (P < 0.05) average daily feed intake by 1.40, 1.11, 1.09 kg/day for BYM, BY and YM compared with the control diet. Pigs fed the control diet had better (P < 0.05) feed efficiency (feed conversion ratio 3.4) than those fed BYM (6.6), BY (5.7) and YM (6.1). The unit cost of diets (Ugandan shillings, USh) increased in the order BYM (USh410) < YM (USh439) < BY (USh551) < commercial diet (USh1313). The unit cost of producing meat increased in the order YM (USh2691) < BYM (USh2713) < BY (USh3150) < commercial diet (USh5331). The highest gross margins accrued from BYM (USh36 769), followed by YM (USh34 853), whereas a loss of USh41 735 was incurred when feeding the commercial diet. Dressing percentage and organ yield were comparable across diets (P > 0.05). Backfat thickness measured at four sites was similar (P > 0.05) across dietary treatments. Conclusion A blended mixture of brewery by-products containing brewers’ spent grain (22%), yeast (15%) and malt dust (60%) is an economical replacement of commercial diets for fattening pigs. Implications Brewery by-products can be used to increase profit margins without affecting the carcass characteristics of pigs.
Climate smart agricultural practices improve soil quality through organic carbon enrichment and lower greenhouse gas emissions in farms of bread bowl of India
Authors: Datta Ashim , Nayak Dali , Smith J. U. , Sharma P. C. , Jat H. S. , Yadav A. K. , Jat M. L.
Published: March 2022

Context Climate change can impact greatly on poorer and vulnerable communities, increasing the risk of natural disasters, and affecting agricultural production. Aims This study aims to explore the potential impacts of climate smart agricultural practices (CSAP) on working farms in Karnal, Haryana, India. Methods Practices studied included zero tillage, crop residue retention and crop diversification. We surveyed soil physical and chemical properties and greenhouse gas emissions on farms managed by either CSAP or conventional agriculture. Soil samples were collected at 0–20 cm depth under wheat grown in the winter season. Key results Of the 70 farmers surveyed, 22 followed CSAP while 48 farmers used conventional practices. Soil pH was lower (7.76) for CSAP farms compared to conventional practices (7.99). Soil carbon was also higher (0.19% compared to 0.13%), as were total organic carbon stock (32.03 Mg ha−1 compared to 25.26 Mg ha−1) and total carbon (0.24% compared to 0.16%). Significant interactions between farming type, pH and organic carbon, gravimetric and volumetric water content were observed. Conservation agriculture registered ∼31% higher soil quality index over conventional practice. Higher wheat grain yield (5.99 t ha−1) was observed under conservation agriculture over conventional (5.49 t ha−1). Greenhouse gas emissions were also ∼63% higher in conventional practices compared to CSAP. Conclusions CSAP can improve soil properties through enrichment in soil organic carbon at the same time as reducing emissions of greenhouse gases. Implications CSAP provide an alternative to conventional agriculture practices in north-west India, irrespective of farm type and size. CSAP not only improve soil carbon pools, but also improve the overall quality of the soil.
Induction of broadly neutralizing antibodies using a secreted form of the hepatitis C virus E1E2 heterodimer as a vaccine candidate
Authors: Wang Ruixue , Suzuki Saori , Guest Johnathan D. , Heller Brigitte , Almeda Maricar , Andrianov Alexander K. , Marin Alexander , Mariuzza Roy A. , Keck Zhen-Yong , Foung Steven K. H. , Yunus Abdul S. , Pierce Brian G. , Toth Eric A. , Ploss Alexander , Fuerst Thomas R.
Published: March 2022

Significance

Hepatitis C virus chronically infects approximately 1% of the world’s population, making an effective vaccine for hepatitis C virus a major unmet public health need. The membrane-associated E1E2 envelope glycoprotein has been used in clinical studies as a vaccine candidate. However, limited neutralization breadth and difficulty in producing large amounts of homogeneous membrane-associated E1E2 have hampered efforts to develop an E1E2-based vaccine. Our previous work described the design and biochemical validation of a native-like soluble secreted form of E1E2 (sE1E2). Here, we describe the immunogenic characterization of the sE1E2 complex. sE1E2 elicited broadly neutralizing antibodies in immunized mice, with increased neutralization breadth relative to the membrane-associated E1E2, thereby validating this platform as a promising model system for vaccine development.
Achieving complete electrooxidation of ethanol by single atomic Rh decoration of Pt nanocubes
Authors: Chang Qiaowan , Hong Youngmin , Lee Hye Jin , Lee Ji Hoon , Ologunagba Damilola , Liang Zhixiu , Kim Jeonghyeon , Kim Mi Ji , Hong Jong Wook , Song Liang , Kattel Shyam , Chen Zheng , Chen Jingguang G. , Choi Sang-Il
Published: March 2022

Significance

Direct ethanol fuel cells are attracting growing attention as portable power sources due to their advantages such as higher mass-energy density than hydrogen and less toxicity than methanol. However, it is challenging to achieve the complete electrooxidation to generate 12 electrons per ethanol, resulting in a low fuel utilization efficiency. This manuscript reports the complete ethanol electrooxidation by engineering efficient catalysts via single-atom modification. The combined electrochemical measurements, in situ characterization, and density functional theory calculations unravel synergistic effects of single Rh atoms and Pt nanocubes and identify reaction pathways leading to the selective C–C bond cleavage to oxidize ethanol to CO
2
. This study provides a unique single-atom approach to tune the activity and selectivity toward complicated electrocatalytic reactions.
Gain of gene regulatory network interconnectivity at the origin of vertebrates
Authors: Gil-Gálvez Alejandro , Jiménez-Gancedo Sandra , Pérez-Posada Alberto , Franke Martin , Acemel Rafael D. , Lin Che-Yi , Chou Cindy , Su Yi-Hsien , Yu Jr-Kai , Bertrand Stephanie , Schubert Michael , Escrivá Héctor , Tena Juan J. , Gómez-Skarmeta José Luis
Published: March 2022

Significance

In this manuscript, we address an essential question in developmental and evolutionary biology: How have changes in gene regulatory networks contributed to the invertebrate-to-vertebrate transition? To address this issue, we perturbed four signaling pathways critical for body plan formation in the cephalochordate amphioxus and in zebrafish and compared the effects of such perturbations on gene expression and gene regulation in both species. Our data reveal that many developmental genes have gained response to these signaling pathways in the vertebrate lineage. Moreover, we show that the interconnectivity between these pathways is much higher in zebrafish than in amphioxus. We conclude that this increased signaling pathway complexity likely contributed to vertebrate morphological novelties during evolution.
Re-sensitization of
mcr
carrying multidrug resistant bacteria to colistin by silver
Authors: Zhang Qi , Wang Runming , Wang Minji , Liu Chunjiao , Koohi-Moghadam Mohamad , Wang Haibo , Ho Pak-Leung , Li Hongyan , Sun Hongzhe
Published: March 2022

Significance

Superbugs carrying a mobile colistin resistance gene (
mcr
) are jeopardizing the clinical efficacy of the last-line antibiotic colistin. The development of MCR inhibitors is urgently required to cope with antibiotic-resistance emergencies. Here, we show that silver (Ag
+
) fully restores the susceptibility of
mcr-1
–carrying superbugs against colistin both in vitro and in vivo. We found an unprecedented tetra-silver center in the active-site pocket of MCR-1 through the substitution of the essential Zn
2+
ions in the intact enzyme, leading to the prevention of substrate binding (i.e. the dysfunction of MCR-1 in transferring phosphorylethanolamine to lipid A). Importantly, the ability of Ag
+
to suppress resistance evolution extends the lifespan of currently used antibiotics, providing a strategy to treat infections by
mcr
-positive bacteria.
Policy discourse in times of crisis
Authors: Álvares Maria
Published: March 2022

The current paper explores the relation between deliberation, political legitimization and decision making in educational policy in the aftermath of the intervention by the troika in Portugal in 2011. Centring on political debates about equal opportunities in education in the Portuguese parliament, it explores how arguments, such as ‘crisis’ and ‘change’, were employed to frame – and covertly promote – a concession of sovereignty to international organizations and legitimize a turn in policy-making to an austerity doctrine regarding education policies. Findings reveal the interplay between a loose and polyphonic discourse of international organizations, and the construction of a narrative of failure regarding educational policies previously adopted, recontextualized and thus enabled the change towards neoliberal policies in Portuguese education policies, bringing about a leaner concept of equal opportunities in education at the national level.
Bilateral Comparison of 1.018 V and 10 V Standards between the SMD (Belgium) and the BIPM, October to December 2021 (part of the ongoing BIPM key comparison BIPM.EM-K11)
Authors: Solve Stephane , Chayramy Regis , Stock Michael , Vlad Dana
Published: March 2022

Main text

As part of the ongoing BIPM key comparison BIPM.EM-K11, a comparison of the 1.018 V and 10 V voltage reference standards of the BIPM and the Service Métrologie - Metrologische Dienst (SMD), Brussels, Belgium, was carried out from October to December 2021. Two BIPM Zener diode-based travelling standards (Fluke 732B), BIPM_B (ZB) and BIPM_6 (Z6), were transported to SMD and back to BIPM by road. At SMD, the reference standard for DC voltage is a Josephson Voltage Standard (JVS). The output EMF (Electromotive Force) of each travelling standard was measured by direct comparison with the primary standard.

The final result of the comparison is presented as the difference between the values assigned to DC voltage standards by SMD, at the level of 1.018 V and 10 V, at SMD, USMD, and those assigned by the BIPM, at the BIPM, UBIPM, at the reference date of the 17th of November 2021.

U
SMD - U
BIPM = -0.03 μV; u
c = 0.13 μV, at 1.018 V

U
SMD - U
BIPM = 0.02 μV; u
c = 0.28 μV, at 10 V

where u
c is the combined standard uncertainty associated with the measured difference, including the uncertainty of the representation of the volt at the BIPM and at SMD, based on KJ, and the uncertainty related to the comparison.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.

The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Temperature and composition of AC arc plasma of medium voltage distribution networks in the air
Authors: Zhou Tong , Yuan Tao , Wei Siyu , He Hengxin , Yang Qing
Published: March 2022

AC electric air arcs in medium voltage (MV) distribution networks, including railway catenary, photovoltaic power generation systems, and traditional distribution networks, can cause insulation damage accidents. Although various studies have been performed on the macroscopic characteristics of the MV AC arc in the air, the research on the physical properties of the arc, such as temperature field and particle composition, is relatively lacking. This work deals with diagnosing the temperature and particle composition of the arc under laboratory conditions based on the arc generation and the moiré deflection diagnosis systems. Based on the experimental results, there are three typical stages in developing the MV AC arc: the initial, transition, and stable combustion. The temperature during the stable combustion of the arc is between 1500 and 2100 K, while the fluctuation period is half a power frequency cycle. The particle components of the arc are mainly composed of O2, N2, and O. Different from the DC arc, the AC arc exhibits a zero-crossing extinguishing phenomenon, while the gap temperature is still high after extinguishing the arc, and the insulation has not been fully restored. This research provides a method for diagnosing MV AC arcs in the air under laboratory conditions and initial values for the arc modeling.
Single-particle spectra in relativistic heavy-ion collisions within the thermal quantum field theory
Authors: Anchishkin D
Published: March 2022

A quantum generalization of the Cooper–Frye recipe is proposed. The calculation of the single-particle spectrum arising in relativistic collisions of particles and nuclei is carried out within the framework of thermal quantum field theory. The starting point of consideration is the solution of the initial-value problem of the radiation of particles from a space-like hypersurface. In the next steps, we obtain a single-particle spectrum using the ‘lesser’ Green’s function associated with the fireball environment. Based on this result, several specific conditions for particle emission are considered.
Raman study of silicon telluride nanoplates and their degradation
Authors: Hathaway Evan , Chen Jiyang , Gonzalez-Rodriguez Roberto , Lin Yuankun , Cui Jingbiao
Published: March 2022

Silicon telluride (Si2Te3) has emerged as one of the many contenders for 2D materials ideal for the fabrication of atomically thin devices. Despite the progress which has been made in the electric and optical properties of silicon telluride, much work is still needed to better understand this material. We report here on the Raman study of Si2Te3 degradation under both annealing and in situ heating with a laser. Both processes caused pristine Si2Te3 to degrade into tellurium and silicon oxide in air in the absence of a protective coating. A previously unreported Raman peak at ∼140 cm−1 was observed from the degraded samples and is found to be associated with pure tellurium. This peak was previously unresolved with the peak at 144 cm−1 for pristine Si2Te3 in the literature and has been erroneously assigned as a signature Raman peak of pure Si2Te3, which has caused incorrect interpretations of experimental data. Our study has led to a fundamental understanding of the Raman peaks in Si2Te3, and helps resolve the inconsistent issues in the literature. This study is not only important for fundamental understanding but also vital for material characterization and applications.
Cycle-consistent learning-based hybrid iterative reconstruction for whole-body PET imaging
Authors: Yang Bao , Zhou Long , Chen Ling , Lu Lijun , Liu Huafeng , Zhu Wentao
Published: March 2022

Objective. To develop a cycle-consistent learning-based hybrid iterative reconstruction (IR) method that takes only slightly longer than analytic reconstruction, while pursuing the image resolution and tumor quantification achievable by IR for whole-body PET imaging. Approach. We backproject the raw positron emission tomography (PET) data to generate a blurred activity distribution. From the backprojection to the IR label, a reconstruction mapping that approximates the deblurring filters for the point spread function and the physical effects of the PET system is unrolled to a neural network with stacked convolutional layers. By minimizing the cycle-consistent loss, we train the reconstruction and inverse mappings simultaneously. Main results. In phantom study, the proposed method results in an absolute relative error (RE) of the mean activity of 4.0% ± 0.7% in the largest hot sphere, similar to the RE of the full-count IR and significantly smaller than that obtained by CycleGAN postprocessing. Achieving a noise reduction of 48.1% ± 0.5% relative to the low-count IR, the proposed method demonstrates advantages over the low-count IR and CycleGAN in terms of resolution maintenance, contrast recovery, and noise reduction. In patient study, the proposed method obtains a noise reduction of 44.6% ± 8.0% for the lung and the liver, while maintaining the regional mean activity in both simulated lesions and real tumors. The run time of the proposed method is only half that of the conventional IR. Significance. The proposed cycle-consistent learning from the backprojection rather than the raw PET data or an IR result enables improved reconstruction accuracy, reduced memory requirements, and fast implementation speeds for clinical whole-body PET imaging.
Intra-breath changes in respiratory mechanics assessed from multi-frequency oscillometry measurements
Authors: Makan Gergely , Dandurand Ronald J , Gingl Zoltán , Hantos Zoltán
Published: March 2022

Objective. Recent studies in respiratory system impedance (Zrs) with single-frequency oscillometry have demonstrated the utility of novel intra-breath measures of Zrs in the detection of pathological alterations in respiratory mechanics. In the present work, we addressed the feasibility of extracting intra-breath information from Zrs data sets obtained with conventional oscillometry.Approach. Multi-frequency recordings obtained in a pulmonology practice were re-analysed to track the 11 Hz component of Zrs during normal breathing and compare the intra-breath measures to that obtained with a single 10 Hz signal in the same subjects. A nonlinear model was employed to simulate changes in Zrs in the breathing cycle. The values of resistance (R) and reactance (X) at end expiration and end inspiration and their corresponding differences (ΔRand ΔX) were compared.Main results. All intra-breath measures exhibited similar mean values at 10 and 11 Hz in each subject; however, the variabilities were higher at 11 Hz, especially for ΔRand ΔX. The poorer quality of the 11 Hz data was primarily caused by the overlapping of modulation side lobes of adjacent oscillation frequencies. This cross-talk was enhanced by double breathing frequency components due to flow nonlinearities.Significance. Retrospective intra-breath assessment of large or special data bases of conventional oscillometry can be performed to better characterise respiratory mechanics in different populations and disease groups. The results also have implications in the optimum design of multiple-frequency oscillometry (avoidance of densely spaced frequencies) and the use of filtering procedures that preserve the intra-breath modulation information.
Coupled multiphysics modeling of the thermal-magnetic-mechanical instability behavior in bulk superconductors during pulsed field magnetization
Authors: Jing Ze
Published: March 2022

Magnetization is of great importance for the application of bulk superconductors. Flux jumps are frequently-encountered challenges during magnetization, leading to sharp temperature rises and material failure, and eventually affecting the field trapping capability of bulk superconductors. Intrinsically, the flux jumps and mechanical failure induced by thermomagnetic instability are coupled with each other, which makes the numerical simulation of the magnetization of bulk superconductors a challenging task. In this paper, a numerical simulation framework is developed based on my previous work (Jing 2020 Supercond. Sci. Technol.
33 075009), which further couples the H-formulation and the phase-field fracture model with the heat diffusion equation to simulate the flux jump and mechanical failure behaviors of bulk superconductors during magnetization. The experimentally observed features of the flux jumps are reproduced, and the corresponding mechanical failure is evaluated. The magnetic field, temperature, stress/strain, and mechanical failure within the bulk sample are presented. It is found that the varying ramp rate of the pulsed field significantly influences the flux jump behaviors of bulk superconductors. The optimum characteristic time

t
0

of the pulsed field for the final trapped field is predicted through numerical simulations.
Atomic and mesoscopic structure of Dy-based surface alloys on noble metals
Authors: Mousavion Sina , Yu Ka Man , Maniraj Mahalingam , Lyu Lu , Knippertz Johannes , Stadtmüller Benjamin , Aeschlimann Martin
Published: March 2022

Surface alloys are a highly flexible class of low dimensional materials with the opportunity to tune and control the spin and charge carrier functionalities on the nanoscale. Here, we focus on the atomic and mesoscopic structural details of three distinct binary rare-earth-noble metals (NM) surface alloys by employing scanning tunneling microscopy and low energy electron diffraction. Using Dysprosium as the guest element on fcc(111) NM substrates, we identify the formation of non-commensurate surface alloy superstructures, which lead to homogeneous moiré patterns for DyCu2/Cu(111) and DyAu2/Au(111), while an inhomogeneous one is found for DyAg2/Ag(111). The local structure was analyzed for these samples and the observed differences are discussed in the light of the lattice mismatches of the alloy layer with respect to the underlying substrate. For the particularly intriguing case of a DyAg2 surface alloy, the surface alloy layer does not show a uniform long-range periodic structure, but consists of local hexagonal tiles separated by extended domain walls, which occur likely to relieve the in-plane strain within the DyAg2 surface alloy layer. Our findings clearly demonstrate that surface alloying is an intriguing tool to tailor the local atomic structure as well as the mesoscopic moiré structures of metallic heterostructures.
Atomic real-space perspective of light-field-driven currents in graphene
Authors: Morimoto Yuya , Shinohara Yasushi , Ishikawa Kenichi L , Hommelhoff Peter
Published: March 2022

When graphene is exposed to a strong few-cycle optical field, a directional electric current can be induced depending on the carrier-envelope phase of the field. This phenomenon has successfully been explained by the charge dynamics in reciprocal space, namely an asymmetry in the conduction band population left after the laser excitation. However, the corresponding real-space perspective has not been explored so far although it could yield knowledge about the atomic origin of the macroscopic currents. In this work, by adapting the nearest-neighbor tight-binding model including overlap integrals and the semiconductor Bloch equation, we reveal the spatial distributions of the light-field-driven currents on the atomic scale and show how they are related to the light-induced changes of charge densities. The atomic-scale currents flow dominantly through the network of the π bonds and are the strongest at the bonds parallel to the field polarization, where an increase of the charge density is observed. The real-space maps of the currents and changes in charge densities are elucidated using simple symmetries connecting real and reciprocal space. We also discuss the strong-field-driven Rabi oscillations appearing in the atomic-scale charge densities. This work highlights the importance of real-space measurements and stimulates future time-resolved atomic-scale experimental studies with high-energy electrons or x-rays, for examples.
Nonlinear Thomson scattering radiation characteristics in tightly focused linearly polarized laser pulses with different pulse widths
Authors: Chang Yifan , Cai Zishuai , Shen Yuting , Tian Youwei
Published: March 2022

In our work, the radiation characteristics of the pulse width for nonlinear Thomson scattering produced by the interaction of a linearly polarized tightly focused laser with a stationary electron are investigated. Theoretical derivation without approximation and numerical simulation results reveal that long pulses imply more complex electrodynamic processes. Radiation bifurcation and coupling phenomena caused by increasing pulse width are found. The radiation energy in the direction of maximum radiation also decreases with the increase of the pulse width. For the first time, the acceleration changes and γ value changes of electron motion caused by linearly polarized laser pulses are shown, and these changes are combined to explain the changes of radiation. At the same time, the full-spatial angular distribution of nonlinear Thomson scattering induced by linearly polarized light was plotted for the first time, and the existence and variation of the radiation angular width were found.
Traffic-related sources may dominate urban water contamination for many organic contaminants
Authors: Awonaike Boluwatife , Parajulee Abha , Lei Ying Duan , Wania Frank
Published: March 2022

Urban runoff and wastewater/sewage input are majorly responsible for the contamination of urban streams. In streams where wastewater input is not a considerable input, the importance of urban runoff as a mechanism of contaminant transport and delivery from urban surfaces to receiving waters is even more apparent. Extensive studies on two such streams in Southern Ontario, Canada yielded data on the occurrence and levels of multiple contaminant groups (polycyclic aromatic hydrocarbons and quinones, benzotriazoles (BTs), BT ultraviolet stabilizers, organophosphate esters, herbicides) and the influence of factors such as temperature, rainfall characteristics, and land use. Here, we collectively examined the data from these studies to identify any trends and further insights. Using concentration-discharge relationships, we found that the transport dynamics of many particle-bound compounds are strikingly similar to each other, and to that of suspended solids in which they were quantified, suggesting a single, predominant source. Similar urban to rural ratios across compound groups and strong correlations with road density further support the existence of a dominant source and point to traffic as this source, respectively. Although road traffic had not previously been implicated as a major source of many of the investigated compound groups, their uses suggest that traffic-related sources are very plausible. Overall, this work highlights that traffic is a major source of a surprisingly wide array of organic contaminants to urban surfaces, and subsequently to nearby streams.
Durability Aspects of Geo-Polymer Mortar Using Single Alkaline Activator Solution
Authors: Mallikarjuna Rao G. , Venu M. , Anil Y. , Noolu Venkatesh
Published: March 2022

The present study mainly focuses on durability aspects of combination of fly Ash and GGBS based geo-polymer mortar were investigated by immersing the mortar cubes in sea water and against 5% sulphuric acid attack. To carry out the experimentation a single alkaline activator solution of sodium silicate (Na2SiO3) was used to produce geo-polymer mortar specimens. In this, varied parameters are mix proportion of fly ash and GGBS and binder (fly ash + GGBS) to fine aggregate selected as 1:1 and 1:3. Similarly alkaline to binder ratio are 0.45and 0.60 respectively. Casted specimens of size 100mmx100mmx100mm and tested for 7 days and 28 days and cured under ambient temperature. In this experimentation varied mix proportions are (100 % FA-0 % GGBS, 75 % FA-25 % GGBS, 50 % FA-50% GGBS, 25 % FA-75 % GGBS, and 0% FA-100 % GGBS). The mixes with higher GGBS content shows greater mass loss and strength degradation when the cubes were immersed in sulphuric acid solution. The obtained results shows that the immersed specimens in sea water shows very less mass loss and strength loss when compared with specimens immersed in sulphuric acid solution.
Creep, chloride, carbonation and sulphate attack on concrete
Authors: Murali Krishna B. , Sai Asrith P. , Tezeswi T.P.
Published: March 2022

Deterioration of concrete structures with age and environmental factors like creep, chloride, carbonation and sulphate attack in the presence of a corrosive environment leads to a decrease in their performance in terms of load-bearing capacity and serviceability. The present work attempts to develop a model for the impairment in the strength of RC beams because of the combined effects of creep and sulphate attack. It also aims at studying the individual effects of chloride carbonation attacks with the help of established deterioration models. The equations of instantaneous elastic modulus and long term creep described in Indian standard codes (IRC 112) enable modelling the deterioration of modulus of elasticity of concrete as a function of time. The influence of sulphate attack on concrete strength against time is obtained from an empirical research study. Standard numerical models are employed to understand the effects of chloride ingress and carbonation phenomena. The consequences of the aforementioned attacks on an M30 grade concrete girder beam are presented in this paper. The results showed that the creep and sulphate attacks tend to dwindle over the course of time, while the effect of the former is more dominant than that of the latter. In addition, the initiation times for carbonation and chloride attacks were estimated, and it was observed that for a pristine RC beam chloride attack is highly imminent than carbonation.
Numerical Simulations of Composite Materials
Authors: Manish Kumar N , Sameer Sk , Divya K
Published: March 2022

Throughout the last decade, the usage of fiber reinforced polymer (FRP) reinforcements in civil infrastructure has risen exponentially, owing to its superior corrosion protection, high durability, and non-magnetization characteristics. Furthermore, as a result of the poor modulus of elasticity of the FRP composites and its non-yielding properties, significant deflection and broad fractures are seen in the FRP reinforced concrete components under consideration. The emphasis of present study is on the behavior of FRP-reinforced concrete beams. The total of nine finite element-based simulations were carried out (ABAQUS). The concrete damage plasticity modelling was considered while performing the analysis. Three different kinds of FRP bars such as CFRP, BFRP, and GFRP, were utilized as reinforcement in longitudinal and transverse direction for concrete beams. Literature was used to validate the numerical findings, and the parametric research has been carried out for varying factors, such as the diameter size, number of bars, the kind of FRP bars used, and the longitudinal arrangement of FRP bars. When CFRP bars were utilized, the load capacity increased by anywhere from 8.88% to 62.92%. Beams that have been reinforced with CFRP carry more weight than beams reinforced with GFRP and BFRP. The increase in CFRP bars tends to give some ductility to the beam via the bi-linear load-to-ductility curve. In similarly, the GFRP reinforced beams improve the ductility of the structure as a whole.
A Study on Strength Characteristics of Steel-Boron Composites as Reinforcement Bars in Reinforced concrete Beam
Authors: Haindavi M , Nipun G
Published: March 2022

Metal matrix composites are the most widely used materials in automotive, aerospace, defense industries etc. The engineering properties of metal matrix composites [MMC] are well known. By relying on MMC’S, civil engineering field has lot of benefits. MMC’S are not well-versed in civil engineering discipline, due to lack of awareness and cost complexes. This paper deals with the study of strength characteristics of steel - boron fiber composite as reinforced bars in concrete beam. For this, steel-boron reinforcement was modelled by assembling the boron fibres [reinforcement] in steel bars [matrix], using ABAQUS software further this steel boron bars were assembled in concrete beam and analysed under required support and loading conditions. From the results it is observed that the strain in conventional steel beam is mor than in MMC reinforced beam, therefore, tensile strain capacity of beam increased by increasing the boron fibres in steel reinforcement.
Reduction of turbidity by adding bio coagulant-A sustainable approach
Authors: Soumya Kiran P. , Reddy Suda V.B.
Published: March 2022

Improper management of human developmental activities such as industrialization and haphazard urban development deteriorating the quality parameters of Surface Water sources beyond the permissible limits. Turbidity in water, a major physical characteristic parameter is highly increasing due to the presence of suspended, colloidal, dissolved solids and making the water resources anaesthetic in condition. The chemical coagulants like Alum, Ferric Sulphate are widely used in turbidity treatment processes. Present study aimed sustainable approach to reduce turbidity by adding Neem (Azadirachta indica) leaf powder as bio coagulant along with Alum (Aluminum Potassium Sulphate). Laboratory investigation was done for the sample from Hussain sagar lake, Telangana, India and analysed the obtained turbidity results. Optimum dosage of neem leaf powder along with Alum has been determined by Jar Test Apparatus to increase the efficiency of treatment. The dose of bio coagulant used was 0.1 to 1gr per Litre. It has been observed that the bio coagulant is efficient in reducing turbidity upto 94.8% when it was added with reduced dosages of Alum. This paper explains sustainable method of reducing turbidity by using neem leaf powder as bio coagulant along with Alum.
An investigation on stabilization of laterite soil using coconut coir fibres
Authors: Naresh J , Kastro Kiran V , Karthik chary T , Jayaram M
Published: March 2022

Laterite soils are highly permeable and make the foundation unsuitable construction. Foundation is a significant structural element which play a key role in safety and stability of structure and it has to be strong enough to support the overlying and underlying structures. This research focuses on stabilizing the laterite soil adding coconut coirs fibres at varying percentages viz., 0.25%, 0.5%, 0.75%, and 1%, which are extracted from coconuts serving as natural fibre for stabilization of soil. The tests such as liquid limit, plastic limit, plasticity index, optimum moisture content, maximum dry density, unconfined compressive strength, and soaked & unsoaked California Bearing Ratio tests were conducted on soil specimens made with varying percentages of coconut coir. It was noted that at 0% addition of coconut coir fibre maximum liquid and plastic limits were obtained and with every increase in the coir content the plasticity index, unconfined compressive strength and California Bearing Ratio strengths were increased. On the other hand, the dry density of all the specimens showed almost equal range of density content and the moisture content was decreased with increase in the coconut coir content. Overall, it was found that stabilization of laterite soil using coconut coir as natural fibres is a cost-effective and eco-friendly approach to improve the properties of soil.
Utilization of Human hair fibre to stabilize Black Cotton Soil and Contaminated Soil
Authors: Sutradhar Rumpa , Reddy Suda V B
Published: March 2022

Land pollution is one of the primary concerns of today. So, conservation of natural resources and utilization of solid waste materials is necessary to deal with the problem of disposal of solid waste. The solid waste can be utilized in the construction and development industries depending on their suitability and attainability. Such a material is human hair fibres which considered as valueless solid waste. These fibres may create environmental problems being non-biodegradable in nature. This paper is focused on utilizing human hair fibre as a stabilizer to modify the properties of soil. It is an analysis to study the influence of Human Hair fibre on the characteristics of black cotton soil and contaminated soil. Human Hair Fibre (natural fibre) is used as a soil strengthening material which can enhance the properties of soil in the field of geotechnical engineering and ground improvement. Human hair fibre is randomly mixed with these soils in the proportion of 0%, 1%, 2%, 3% and 4% by weight of soil. The properties such as free swell index, specific gravity, index properties and strength were determined and compared with non-reinforced soil. The findings show an enhancement in the properties of soil with the inclusion of human hair fibre.
Linear Regression Analysis on the Contributory Factor of Accident Identified in Road Safety Audit Using Python
Authors: Sreeparvathy CM , Sravanti Chitturi
Published: March 2022

The rising number of road accidents in Indian Scenario is quite alarming. The analysis of cause of these accidents will help to adopt remedial measures for the same. In this paper based on the data collected using Road Safety Audit (RSA), an attempt is made to analyze and understand the root cause for accident. The linear equation and relationship is developed using Python programming which is a competent tool for analysis. In this paper, the analysis is carried out on data collected along a stretch of 12 km of length of road from Langerhouz (suburban Road) to MGIT. RSA was conducted for the same stretch that has six intersections falling along the stretch. The basic methodology used for data collections were Prompt list, volume and accident data collection. The accident data were analyzed statistically and a linear regression model was generated with various causes of the accident as the independent variable. For the purpose of analysis, the stretch was divided into four sub stretch based on the similarities in the geometric properties of the road. RSA was also performed for the six intersections falling in this stretch. The data collected on accident has reflected on a number of contributory factorsfrom which the main causative factors were identified and recommendations were made to improve safety with the best possible solutions. Regression analysis was conducted for the accident data obtained from the police station for the years 2014 – 2018. The solution of the regression equation is developed using Python programming language. The relation to dependent variable, accident was formulated linearly using the independent variable based on the factors contributing to accident.